S-8355/56/57/58 Series

Transcription

1 Rev.1.11 ULTRASMALL PACKAGE PWM CONTROL, PWM/PFM SWITCHING CONTROL STEPUP SWITCHING REGULATOR S8355/56/57/58 Series The S8355/56/57/58 Series is a CMOS stepup switching regulator which mainly consists of a reference voltage source, an oscillation circuit, an error amplifier, a phase compensation circuit, a PWM control circuit (S8355/57) and a PWM/PFM switching control circuit (S8356/58). With an external lowonresistance Nch Power MOS, this product is applicable to applications requiring high efficiency and high output current. The S8355/57 Series realizes low ripple, high efficiency, and excellent transient characteristics with the PWM control circuit whose duty ratio can vary from % to 83 % (from % to 78 % for 5 khz and 3 khz models), the bestdesigned error amplifier and phase compensation circuits. The S8356/58 Series switches its operation to the PFM control circuit whose duty ratio is 15 % with to the PWM/PFM switching control circuit under a light load and to prevent decline in the efficiency by IC operation current. Features Low voltage operation: Startup is guaranteed from.9 V(I OUT =1 ma ) Low current consumption: During operation: 5.9 µa (3.3 V, 1 khz, typ.) During shutdown:.5 µa (max.) Duty ratio: Builtin PWM/PFM switching control circuit (S8356/58) 15 to 83 % (1 khz models), 15 to 78 % (5 khz and 3 khz models) External parts: coil, diode, capacitor, and transistor Output voltage:.1 V step setting is available between 1.5 and 6.5 V (for V DD /V OUT separate types) or. and 6.5 V (for other than V DD /V OUT separate types). Accuracy of ±.4 %. Oscillation frequency: 1, 5, and 3 khz Soft start function: 6 ms (1 khz, typ.) Shutdown function Packages SOT33 (Package code : MP3A) SOT35 (Package code : MP5A) SOT893 (Package code : UP3A) 6Pin SNB(B) (Package code : BD6A) Applications Power supplies for portable equipment such as digital cameras, electronic notebooks, and PDAs Power supplies for audio equipment such as portable CD/MD players Constant voltage power supplies for cameras, video equipment, and communications equipment Power supplies for microcomputers Seiko Instruments Inc. 1

2 S8355/56/57/58 Series Rev Block Diagram (1) S8357/58 Series B, H, F Type (No shutdown function) () S8357/58 Series B, H, F Type (Shutdown function included) EXT Oscillation Circuit PWM or PWM /PFM switching control circuit Soft start builtin reference power supply IC internal power supply Phase compensation circuit VSS EXT Oscillation Circuit PWM or PWM /PFM switching control circuit Soft start builtin reference power supply IC internal power supply Phase compensation circuit VSS ON/ OFF (3) S8357/58 Series E, J, G Type (V DD/V OUT separate type) (4) S8355/56 Series K, L, M Type VDD VDD EXT Oscillation Circuit PWM or PWM /PFM switching control circuit IC internal power supply EXT Oscillation Circuit PWM or PWM /PFM switching control circuit IC internal power supply Soft start builtin reference power supply Phase compensation circuit VSS Soft start builtin reference power supply Phase compensation circuit VSS Selection Guide 1. Function List Figure 1 Block Diagram ON/ OFF Product name Control system Switching frequency (khz) Shutdown function V DD /V OUT separate type Package Application S8355KxxMC PWM 1 Yes Yes SOT35 Application which needs an variable output voltage and a shutdown function S8355LxxMC/BD PWM 5 Yes Yes Application which needs an variable output voltage, a shutdown function SOT35 / 6Pin SNB(B) and a thin coil S8355MxxMC/BD PWM 3 Yes Yes Application which needs an variable output voltage, a shutdown function SOT35 / 6 PinSNB(B) and a thin coil S8357BxxMC PWM 1 Yes SOT35 Application which needs a shutdown function S8357BxxMA PWM 1 SOT33 Application with an unnecessary shutdown function S8357BxxUA PWM 1 SOT893 Application with an unnecessary shutdown function S8357ExxMC PWM 1 Yes SOT35 Application which adjusts output voltage by external resistor S8357FxxMC/BD PWM 3 Yes SOT35 / 6Pin SNB(B) Application which needs a shutdown function and a thin coil S8357GxxMC/BD PWM 3 Yes SOT35 / 6Pin SNB(B) Application which needs an variable output voltage and a thin coil S8357HxxMC/BD PWM 5 Yes SOT35 / 6Pin SNB(B) Application which needs a shutdown function and a thin coil S8357JxxMC/BD PWM 5 Yes Application which needs an variable output voltage with an external resistor SOT35 / 6Pin SNB(B) and a thin coil S8356KxxMC PWM/PFM switching 1 Yes Yes SOT35 Application which needs an variable output voltage and a shutdown function S8356LxxMC/BD PWM/PFM Application which needs an variable output voltage, a shutdown function 5 Yes Yes SOT35 / 6Pin SNB(B) switching and a thin coil S8356MxxMC/BD PWM/PFM Application which needs an variable output voltage, a shutdown function 3 Yes Yes SOT35 / 6Pin SNB(B) switching and a thin coil S8358BxxMC PWM/PFM switching 1 Yes SOT35 Application which needs a shutdown function S8358BxxMA PWM/PFM switching 1 SOT33 Application with an unnecessary shutdown function S8358BxxUA PWM/PFM switching 1 SOT893 Application with an unnecessary shutdown function S8358ExxMC PWM/PFM switching 1 Yes SOT35 Application which adjusts output voltage by external resistor S8358FxxMC/BD PWM/PFM switching 3 Yes SOT35 / 6Pin SNB(B) Application which needs a shutdown function and a thin coil S8358GxxMC/BD PWM/PFM switching 3 Yes SOT35 / 6Pin SNB(B) Application which needs an variable output voltage and a thin coil S8358HxxMC/BD PWM/PFM switching 5 Yes SOT35 / 6Pin SNB(B) Application which needs a shutdown function and a thin coil S8358JxxMC/BD PWM/PFM switching Application which needs an variable output voltage with an external resistor 5 Yes SOT35 / 6Pin SNB(B) and a thin coil Seiko Instruments Inc.

3 Rev S8355/56/57/58 Series. Product Name S835 x x xx xx xxx Tx IC direction in tape specification T ; SOT33, SOT35, SOT893 TF ; 6Pin SNB(B) Product name (abbreviation) Package name (abbreviation) MA ; SOT33 MC ; SOT35 UA ; SOT893 BD ; 6 PinSNB(B) Output voltage ( 1) 18 to 5 (1.8 to 5. V) Product type B ; Normal product, f OSC= 1 khz (S8357/58) H ; Normal product, f OSC = 5 khz (S8357/58) F ; Normal product, f OSC = 3 khz (S8357/58) E ; V DD/V OUT separate type, f OSC = 1 khz (S8357/58) J ; V DD/V OUT separate type, f OSC = 5 khz (S8357/58) G ; V DD/V OUT separate type, f OSC = 3 khz (S8357/58) K ; Shutdown function V DD/V OUT separate type, f OSC = 1 khz (S8355/56) L ; Shutdown function V DD/V OUT separate type, f OSC = 5 khz (S8355/56) M ; Shutdown function V DD/V OUT separate type, f OSC = 3 khz (S8355/56) Control system 5 or 7 ; PWM control 6 or 8 ; PWM/PFM switching control 3. Package and Function List by Product Type Series name S8355 Series S8356 Series S8357 Series S8358 Series Type K, L, M (Shutdown function V DD/V OUT separate type) K = 1 khz, L = 5 khz, M = 3 khz B, H, F (Normal product) B = 1 khz, H = 5 khz, F = 3 khz E, J, G (V DD/V OUT separate type) E = 1 khz, J = 5 khz, G = 3 khz B, H, F (Normal product) B = 1 khz, H = 5 khz, F = 3 khz E, J, G (V DD /V OUT separate type) E=1 khz, J=5 khz, G=3 khz Package name (abbreviation) MC BD MA UA MC BD MC BD MA UA MC BD MC BD Shutdown function Yes / No Yes No Yes No No Yes No V DD/V OUT separate type Yes / No Yes No Yes No Yes Seiko Instruments Inc. 3

4 S8355/56/57/58 Series Rev Product Name List Output voltage (V) S8355KxxMC Series S8355MxxBD Series S8355MxxMC Series 1.8 S8355K18MCNADT S8355M18BDMCDTF S8355M18MCMCDT 5. Output voltage (V) S8356KxxMC Series S8356MxxBD Series S8356MxxMC Series 1.8 S8356K18MCNEDT S8356M18BDMEDTF S8356M18MCMEDT 5. S8356M5MCMFJT Output voltage (V) S8357BxxMC Series S8357FxxMC Series S8357GxxMC Series 3.3 S8357B33MCNIST S8357F33MCMGST 5. S8357B5MCNJJT S8357F5MCMHJT S8357G5MCMJJT Output voltage (V) S8358BxxMC Series S8358GxxMC Series 3.3 S8358B33MCNQST 5. S8358B5MCNRJT S8358G5MCMNJT Please consult our sales person for products with an output voltage other than specified above. 4 Seiko Instruments Inc.

5 Rev S8355/56/57/58 Series Pin Assignment Top view 1 Top view Top view 5 4 Top view SOT SOT SOT Pin SNB(B) Figure Pin Assignment Without shutdown function, V DD/V OUT nonseparate type Products: S8357/58 Series B, H, F Type Packages: SOT33 Pin No. Pin Name Functions 1 Output voltage pin and IC power supply pin VSS GND pin 3 EXT External transistor connection pin Without shutdown function, V DD/V OUT nonseparate type Products: S8357/58 Series B, H, F Type Packages: SOT893 Pin No. Pin Name Functions 1 VSS GND pin Output voltage pin and IC power supply pin 3 EXT External transistor connection pin With shutdown function, V DD/V OUT nonseparate type Products: S8357/58 Series B, H, F Type Packages: SOT35 Pin No. Pin Name Functions 1 ON/OFF Shutdown pin H : Normal operation (stepup oepration) L : Stop stepup (whole circuit stop) Output voltage pin and IC power supply pin 3 (N.C.) 4 VSS GND pin 5 EXT External transistor connection pin With shutdown function, V DD/V OUT nonseparate type Products: S8357/58 Series B, H, F Type Packages: 6Pin SNB(B) Pin No. Pin Name Functions 1 (N.C.) ON/OFF Shutdown pin H : Normal operation (stepup oepration) L : Stop stepup (whole circuit stop) 3 Output voltage pin and IC power supply pin 4 EXT External transistor connection pin 5 (N.C.) 6 VSS GND pin Without shutdown function, V DD/V OUT separate type Products: S8357/58 Series E, J, G Type Packages: SOT35 Pin No. Pin Name Functions 1 Output voltage pin VDD IC power supply pin 3 (N.C.) 4 VSS GND pin 5 EXT External transistor connection pin Without shutdown function, V DD/V OUT separate type Products: S8357/58 Series E, J, G Type Packages 6Pin SNB(B) Pin No. Pin Name Functions 1 (N.C.) Output voltage pin 3 VDD IC power supply pin 4 EXT External transistor connection pin 5 (N.C.) 6 VSS GND pin With shutdown function, V DD/V OUT separate type Products: S8355/56 Series K, L, M Type Packages: SOT35 Pin No. Pin Name Functions 1 Output voltage pin VDD IC power supply pin 3 ON/OFF Shutdown pin H : Normal operation (stepup oepration) L : Stop stepup (whole circuit stop) 4 VSS GND pin 5 EXT External transistor connection pin With shutdown function, V DD/V OUT separate type Products: S8355/56 Series K, L, M Type Packages: 6Pin SNB(B) Pin No. Pin Name Functions 1 ON/OFF Shutdown pin H : Normal operation (stepup oepration) L : Stop stepup (whole circuit stop) Output voltage pin 3 VDD IC power supply pin 4 EXT External transistor connection pin 5 (N.C.) 6 VSS GND pin Seiko Instruments Inc. 5

6 S8355/56/57/58 Series Rev Absolute Maximum Ratings (Unless otherwise specified: Ta=5 C) Parameter Symbol Ratings Unit Power dissipation P D pin voltage V OUT V SS.3 to V SS1 ON/OFF pin voltage 1) V ON/OFF V SS.3 to V SS1 VDD pin voltage ) V DD V SS.3 to V SS1 V EXT pin voltage V EXT B, H, F type V SS.3 to V OUT.3 Others V SS.3 to V DD.3 EXT pin current I EXT ±8 ma SOT893 5 SOT35 5 SOT33 15 mw 6Pin SNB(B) 9 Operating temperature T opr 4 to 85 Storage temperature T stg 4 to 15 1) With shutdown function ) For VDD/ separate types Note: Although the IC contains protection circuit against static electricity, excessive static electricity or voltage which exceeds the limit of the protection circuit should not be applied to. C 6 Seiko Instruments Inc.

7 Rev S8355/56/57/58 Series Electrical Characteristics 1kHz types (S835xBxx, S835xExx, S835xKxx) (Unless otherwise specified: Ta = 5 C) Parameter Symbol Conditions Min. Typ. Max. Unit Test circuit V Output voltage V OUT (S) V OUT V.976 OUT (S) OUT (S) 1.4 Input voltage 1 Operation start voltage V ST1 I OUT = 1 ma.9 V Oscillation start voltage V ST No external parts, voltage applied to V OUT.8 1 Operation holding I V OUT = 1 ma, Measured by decreasing voltage voltage HLD gradually.7 S835xx15 to S835xx to Current consumption 1 I SS1 V OUT = V OUT (S).95 S835xx3 to S835xx4 to S835xx5 to S835xx6 to S835xx15 to S835xx to µa Current consumption I SS V OUT = V OUT (S).5 S835xx3 to S835xx4 to S835xx5 to S835xx6 to Current consumption during shutdown I SSS V ON/OFF = V.5 (with shutdown function) 1 S835xx15 to S835xx to S835xx5 to I EXTH V EXT = V OUT.4 S835xx3 to S835xx4 to S835xx5 to EXT pin output current S835xx6 to S835xx15 to ma S835xx to S835xx5 to I EXTL V EXT =.4 V S835xx3 to S835xx4 to S835xx5 to S835xx6 to Line regulation V OUT1 = V OUT (S).4 to Load regulation V OUT I OUT = 1 µa to V OUT (S) / mv Output voltage temperature coefficient V OUT Ta Ta = 4 C to 85 C ±5 ppm/ C Oscillation frequency f OSC V OUT = V OUT (S) khz Max. duty ratio MaxDuty V OUT = V OUT (S) PWM/PFM switching % PFMDuty V duty ratio (S8356/58) IN = V OUT (S).1 V, no load Shutdown pin input V SH Judged the oscillation at EXT pin.75 voltage (for shutdown V SL1 Judged the stop of When V OUT 1.5 V.3 V function builtin type) V SL oscillation at EXT pin When V OUT<1.5 V. Shutdown pin input I SH Shutdown pin = V OUT (S) current (for shutdown µa function builtin type) I SL Shutdown pin = V.1.1 Soft start time t SS ms Efficiency EFFI 86 % External parts Coil : CDRH6D847 of Sumida Corporation Diode : RB461F(Schottky type) of Rohm Co., Ltd. Capacitor : F93(16 V, 47 µf tantalum type) of Nichicon Corporation Transistor : CPH31 of Sanyo Electric Co., Ltd. Base resister (Rb) : 1. kω Base capacitor (Cb) : pf (ceramic type) = V OUT (S).6 applied, I OUT = V OUT (S) / 5 Ω The shutdown function builtin type: ON/OFF pin is connected to V OUT V DD /V OUT separate type : VDD pin is connected to pin Note 1 : V OUT (S) specified above is the set output voltage value, and V OUT is the typical value of the output voltage. Note : V DD /V OUT separate type: Stepup operation is performed from V DD=.8 V. However, 1.8 V DD 1 V is recommended to stabilize the output voltage and oscillation frequency. (You must apply V DD 1.8 V for products with a set value of less than 1.9 V.) 1 Seiko Instruments Inc. 7

8 S8355/56/57/58 Series Rev kHz types (S835xHxx, S835xJxx, S835xLxx) (Unless otherwise specified: Ta = 5 C) Parameter Symbol Conditions Min. Typ. Max. Unit Test circuit V Output voltage V OUT (S) V OUT V.976 OUT (S) OUT (S) 1.4 Input voltage 1 Operation start voltage V ST1 I OUT = 1 ma.9 V Oscillation start voltage V ST No external parts, voltage applied to V OUT.8 1 Operation holding I V OUT = 1 ma, Measured by decreasing voltage voltage HLD gradually.7 S835xx15 to S835xx to Current consumption 1 I SS1 V OUT = V OUT (S).95 S835xx3 to S835xx4 to S835xx5 to S835xx6 to S835xx15 to S835xx to µa Current consumption I SS V OUT = V OUT (S).5 S835xx3 to S835xx4 to S835xx5 to S835xx6 to Current consumption during shutdown I SSS V ON/OFF = V.5 (with shutdown function) 1 S835xx15 to S835xx to S835xx5 to I EXTH V EXT = V OUT.4 S835xx3 to S835xx4 to S835xx5 to EXT pin output current S835xx6 to S835xx15 to ma S835xx to S835xx5 to I EXTL V EXT =.4 V S835xx3 to S835xx4 to S835xx5 to S835xx6 to Line regulation V OUT1 = V OUT (S).4 to Load regulation V OUT I OUT = 1 µa to V OUT (S) / mv Output voltage temperature coefficient V OUT Ta Ta = 4 C to 85 C ±5 ppm/ C Oscillation frequency f OSC V OUT = V OUT (S) khz Max. duty ratio MaxDuty V OUT = V OUT (S) PWM/PFM switching % PFMDuty V duty ratio (S8356/58) IN = V OUT (S).1 V, no load Shutdown pin input V SH Judged the oscillation at EXT pin.75 voltage (for shutdown V SL1 Judged the stop of When V OUT 1.5 V.3 V function builtin type) V SL oscillation at EXT pin When V OUT <1.5 V. Shutdown pin input current (for shutdown I SH Shutdown pin = V OUT (S) function builtin type) I SL Shutdown pin = V.1.1 µa Soft start time t SS ms Efficiency EFFI 85 % External parts Coil : CDRH6D8 of Sumida Corporation Diode : RB461F(Schottky type) of Rohm Co., Ltd. Capacitor : F93(16 V, 47 µf tantalum type) of Nichicon Corporation Transistor CPH31 of Sanyo Electric Co., Ltd. Base resister (Rb) : 1. kω Base capacitor (Cb) : pf (ceramic type) = V OUT (S).6 applied, I OUT = V OUT (S) / 5 Ω The shutdown function builtin type : ON/OFF pin is connected to V OUT V DD /V OUT separate type : VDD pin is connected to pin Note 1 : V OUT (S) specified above is the set output voltage value, and V OUT is the typical value of the output voltage. Note : V DD /V OUT separate type: Stepup operation is performed from V DD =.8 V. However, 1.8 V DD 1 V is recommended to stabilize the output voltage and oscillation frequency. (You must apply V DD 1.8 V for products with a set value of less than 1.9 V.) 1 8 Seiko Instruments Inc.

9 Rev S8355/56/57/58 Series 3kHz types (S835xFxx, S835xGxx, S835xMxx) (Unless otherwise specified: Ta = 5 C) Parameter Symbol Conditions Min. Typ. Max. Unit Test circuit V Output voltage V OUT (S) V OUT V.976 OUT (S) OUT (S) 1.4 Input voltage 1 Operation start voltage V ST1 I OUT = 1 ma.9 V Oscillation start voltage V ST No external parts, voltage applied to V OUT.8 1 Operation holding I V OUT = 1 ma, Measured by decreasing voltage voltage HLD gradually.7 S835xx15 to S835xx to Current consumption 1 I SS1 V OUT = V OUT (S).95 S835xx3 to S835xx4 to S835xx5 to S835xx6 to S835xx15 to S835xx to µa Current consumption I SS V OUT = V OUT (S).5 S835xx3 to S835xx4 to S835xx5 to S835xx6 to Current consumption during shutdown I SSS V ON/OFF = V.5 (with shutdown function) 1 S835xx15 to S835xx to S835xx5 to I EXTH V EXT = V OUT.4 S835xx3 to S835xx4 to S835xx5 to EXT pin output current S835xx6 to S835xx15 to S835xx to S835xx5 to I EXTL V EXT =.4 V S835xx3 to S835xx4 to S835xx5 to S835xx6 to Line regulation V OUT1 = V OUT (S).4 to Load regulation V OUT I OUT = 1 µa to V OUT (S) / Output voltage temperature coefficient V OUT Ta Ta = 4 C to 85 C ±5 ppm/ C Oscillation frequency f OSC V OUT = V OUT (S) khz Max. duty ratio MaxDuty V OUT = V OUT (S) PWM/PFM switching % PFMDuty V duty ratio (S8356/58) IN = V OUT (S).1 V, no load Shutdown pin input V SH Judged the oscillation at EXT pin.75 voltage (for shutdown V SL1 Judged the stop of When V OUT 1.5 V.3 V function builtin type) V SL oscillation at EXT pin When V OUT<1.5 V. Shutdown pin input I SH Shutdown pin = V OUT (S) current (for shutdown µa function builtin type) I SL Shutdown pin = V.1.1 Soft start time t SS ms Efficiency EFFI 85 % External parts Coil : CDRH6D8 of Sumida Corporation Diode : RB461F(Schottky type) of Rohm Co., Ltd. Capacitor : F93(16 V, 47 µf tantalum type) of Nichicon Corporation Transistor : CPH31 of Sanyo Electric Co., Ltd. Base resister (Rb) : 1. kω Base capacitor (Cb) : pf (ceramic type) = V OUT (S).6 applied, I OUT = V OUT (S) / 5 Ω The shutdown function builtin type: ON/OFF pin is connected to V OUT V DD /V OUT separate type : VDD pin is connected to pin Note 1 : V OUT (S) specified above is the set output voltage value, and V OUT is the typical value of the output voltage. Note : V DD /V OUT separate type: Stepup operation is performed from V DD =.8 V. However, 1.8 V DD 1 V is recommended to stabilize the output voltage and oscillation frequency. (You must apply V DD 1.8 V for products with a set value of less than 1.9 V.) ma mv 1 Seiko Instruments Inc. 9

10 S8355/56/57/58 Series Rev Test Circuits 1. EXT Oscilloscope (ON/OFF) A VSS (VDD).1µF. Cb Rb EXT (VDD) V VSS (ON/OFF).1µF Figure 3 Test Circuits 1, Operation 1. Stepup DC/DC Converter The S8355/57 Series is a DC/DC converter using a pulse width modulation method (PWM) and features a low current consumption. In conventional PFM DC/DC converters, pulses are skipped at low output load current, causing fluctuation in ripple frequency of the output voltage, with the result of increase in ripple voltage. In S8355/57 Series, the switching frequency does not change, although the pulse width changes from % to 83 % (78 % for F, G, H, J, L, and M type) corresponding to each load current. The ripple voltage generated from switching can thus be removed easily through the filter because the switching frequency is constant. S8356/58 Series is a DC/DC converter that atuomatically switches a pulse width modulation method (PWM) and a pulse frequency modulation method (PFM) and features a low current consumption. Especially, the series is a highly efficient DC/DC converter at an output current of around 1 µa. In conventional constantduty PFM DC/DC converters, pulses are skipped at low output load current, causing fluctuation in ripple frequency of the output voltage, with the result of increase in ripple voltage. The S8356/58 Series performs under the PWM control with the pulse width duty changing from 15 % to 83 % (78 % for F, G, H, J, L, and M Series) at high output load current. 1 Seiko Instruments Inc.

11 Rev S8355/56/57/58 Series On the other hand, the S8356/58 Series performs under the PFM control with the pulse width duty fixed at 15 % at low output load current, and pulses are skipped at low output load current according to the load current and output to the switching transister. The oscillation circuit thus oscillates intermittently so that the resultant lower selfconsumption could prevent the efficiency from reducing at low load current. A switching point from the PWM control to the PFM control depends on the external devices (coil, diode, etc.), input voltage and output voltage. For this IC, the builtin soft start circuit controls a rush current and overshoot of the output voltage when powering on or the ON/OFF pin is turned to H level. Shutdown pin: Stops or starts stepup operation. (Only for SOT35 package products of B, H, F, K, L and M type and for 6pin SNB(B) package products.) Turning the shutdown pin to L level stops operation of all the internal circuits and reduces current consumption significantly. DO NOT use the shutdown pin in floating state because it has a structure shown in Figure 4 and is not pulled up or pulled down internally. DO NOT apply voltage of between.3 V and.75 V to the shutdown pin because applying such voltage increases the current consumption. If the shutdown pin is not used, connect it to (VDD for K, L and M type) pin. The shutdown pin doesn t have hysteresis. (VDD for K, L and M types) Shutdown pin CR oscillation circuit Output voltage ON/OFF H Operation Fixed L Stop * * Voltage obtained by extracting the voltage drop due to DC resistance of the inductor and the diode forward voltage from. VSS Figure 4 Shutdown pin structure L CONT D M1 EXT VSS C L Figure 5 Stepup switching regulator circuit for basic equations Seiko Instruments Inc. 11

12 S8355/56/57/58 Series Rev The following are basic equations [(1) through (7)] of the stepup switching regulator (see Figure 5.) Voltage at CONT pin at the moment M1 is turned ON (current I L flowing through L is zero), V A : V A =V S... (1) The change in I L over time: (V S : Nonsaturated voltage of M1) di L dt V = L V = IN V S... () L L Integration of the above equation (I L ) : V S I L =... (3) L I L flows while M1 is ON (t ON ). The time of t ON is determined by the oscillation frequency of the OSC. The peak current (I PK ) after t ON : V I PK = IN V S t on... (4) L The energy stored in L is represented with 1/ L (I PK ). When M1 is turned OFF (t OFF ), the energy stored in L is transmitted through a diode to the output capacitor. Then, reverse voltage (V L ) is generated: V L = (V OUT V D )... (5) (V D : Diode forward voltage) The voltage at CONT pin rises only by V OUT V D. The change in the current (I L ) flowing through the diode into V OUT during t OFF : di L dt V L V OUT V D = =... (6) L L Integration of the above equation is as follows: V OUT V D I L = I PK t...(7) L During t ON, the energy is stored in L and is not transmitted to V OUT. When receiving output current (I OUT ) from V OUT, the energy of the capacitor (C L ) is consumed. As a result, the pin voltage of C L is reduced, and goes to the lowest level after M1 is turned ON (t ON ). When M1 is turned OFF, the energy stored in L is transmitted through the diode to C L, and the voltage of C L rises drastically. V OUT is a time function that indicates the maximum value (ripple voltage: V P P ) when the current flowing through into V OUT and load current (I OUT ) match. 1 Seiko Instruments Inc.

13 Rev S8355/56/57/58 Series Next, the ripple voltage is found out as follows: I OUT vs t 1 (time) from when M1 is turned OFF (after t ON ) to when V OUT reaches the maximum level: V OUT V D I OUT = I PK t 1... (8) L L t 1 = (I PK I OUT )... (9) V OUT V D When M1 is turned ON (after t OFF ), I L = (when the energy of the inductor is completely transmitted): Based on equation (7), L V OUT V D t OFF I PK =...(1) When substituting equation (1) for equation (9), I OUT t 1 = t OFF t OFF... (11) I PK Electric charge Q 1 which is charged in C L during t 1 : t Q 1 = 1 t I L dt = I PK 1 V dt... OUT V D t 1 tdt L V OUT V D 1 = I PK t 1 t 1... (1) L When substituting equation (1) for equation (9): Q 1 = I PK 1 I PK I OUT (I PK I OUT ) t 1 = t 1... (13) A rise in voltage (V P P ) due to Q 1: Q 1 1 I PK I OUT V PP = = t1... (14) C L C L When taking into consideration I OUT to be consumed during t 1 and ESR (Equivalent Series Resistance) of C L, namely R ESR : Q 1 1 I PK I OUT I V PP = = t1 PK I OUT I OUT t 1 R ESR... (15) C L C L C L When substituting equation (11) for equation (15): (I PK I OUT ) t OFF I PK I OUT V PP = R ESR... (16) I PK C L Therefore to reduce the ripple voltage, it is important that the capacitor connected to the output pin has a large capacity and a small ESR. Seiko Instruments Inc. 13

14 S8355/56/57/58 Series Rev External parts selection for DC/DC converter The relationship between major characteristics of the stepup circuit and characteristics parameters of the external parts are shown in Figure 6. For larger output current? For higher efficiency? Operation efficiency Standby efficiency For smaller ripple voltage? smaller inductance larger inductance smaller DC resistance of inductor larger output capacitance larger output capacitance With MOS FET, smaller ON resistance With MOS FET, smaller input capacitance With bipolar transistor, smaller external resistance Rb With bipolar transistor, larger external resistance Rb Figure 6 Relationship between major characterstics of the stepup circuit and external parts 14 Seiko Instruments Inc.

15 Rev S8355/56/57/58 Series 1. Inductor An inductance has strong influence on maximum output current I OUT and efficiency η. Figure 7 shows the relation between I OUT, and η characteristics to L of S8355/56/57/58. F, G, H, J, L, M Type CDRH6D8 V OUT=5. V, =3. V I OUT Efficienccy decreases I OUT decreases I PK increases Coil size: smaller η Recommended range Efficienccy decreases I OUT decreases I PK decreases Coil size: bigger 4.7 L (µh) 47 Figure 7 LI OUT and η characteristics The peak current (I PK ) increases by decreasing L and the stability of a circuit improves and I OUT increases. If L is furthermore made small, efficiency falls and in running short, I OUT decreases. (Based on the current drive capability of external switching transistor.) The loss of I PK by the switching transistor decreases by increasing L and the efficiency becomes maximum at a certain L value. Further increasing L decreases efficiency due to the loss of DC resistance of the coil. Also, I OUT decreases, too. Oscillation frequency is higher, smaller one can be choosed and also makes coil smaller. The recommended inductances are to 1 µh inductor for B, E,and K type, 4.7 to 47 µh inductor for F, G, H, J, L, and M type. Choose a value for L by refering to the reference data because the maximum output current is due to the input voltage in an actual case. Choose an inductor so that I PK does not exceed the allowable current. Exceeding the allowable current of the inductor causes magnetic saturation, remarkable low efficiency and destruction of the IC chip due to a large current. I PK in uncontinuous mode is caluculated from the following equatuon: I PK = I OUT (V OUT V D ) f OSC L (A)... (17) fosc = oscillation frequency, V D.4 V. Seiko Instruments Inc. 15

16 S8355/56/57/58 Series Rev Diode Use an external diode that meets the following requirements: Low forward voltage: (V F <.3 V) High switching speed: (5 ns max.) Reverse voltage: V OUT V F or more Rated current:i PK or more 3. Capacitor (C IN, C L ) A capacitor at the input side (C IN ) improves the efficiency by reducing the power impedance and stabilizing the input current. Select a C IN value according to the impedance of the power supply used. A capacitor at the output side (C L ) is used for smoothing the output voltage. For stepup types, the output voltage flows intermittently to the load current so that stepup types need a larger capacitance than stepdown types. Therefore, select an appropriate capacitor depending on the ripple voltage that increases in case of a higher output voltage or a higher load current. The capacitor value should be 1 µf minimum. Select an appropriate capacitor with an ESR (Equivalent Series Resistance) for stable output voltage. A stable range of the volatge at this IC depends on the ESR. Although the inductance (L) is also a factor, an ESR of 3 mω to 5 mω draws out the characteristics. However, the best ESR may depend on L, capacitance, wiring and applications (output load). Therefore, fully evaluate ESRs under an actual condition to determine the best value. Figure 19 of Application Circuit shows an example of circuit that uses a ceramic capacitor and the external resiatance (ESR) for your reference. 4. External transistor A bipolar (NPN) transistor or an enhancement (Nchannel) MOS FET transistor can be used as external transistor. 4.1 Bipolar (NPN) transistor A circuit example using a bipolar transistor (NPN), Sanyo Electric Co., Ltd. CPH31 (h FE = to 56) is shown in Figure 1. The h FE value and the Rb value determine the driving capacity to increase the output current using a bipolar transistor. A peripheral circuit example of the transistor is shown in Figure 8. Pch (VDD for E, G, J, K, L, M type) Cb pf I PK Rb EXT 1 kω Nch Figure 8 External transistor peripheral 16 Seiko Instruments Inc.

17 Rev S8355/56/57/58 Series 1 kω is recommended for Rb. Rb is selected from the following caluculation. Caluculate the necessary base current (I b ) from the bipolar transistor h FE using I b =I PK /h FE. Rb= V OUT.7 I b.4 I EXTH ( Rb= V DD.7.4 I b I EXTH for E,G,J,K,L,and M types) A small Rb increases output current, however, the efficiency decreases. The current flows pulsating and there is voltage drop due to wiring resistance in an actual circuit, therefore the optimum Rb value should be determined by experiment. A speedup capacitor (Cb) connected in parallel with Rb resistance as shown in Figure 8 decreases the switching loss and improves the efficiency. Cb is caluculated from the following equatuon: 1 Cb π Rb f OSC.7 However, in practice, the optimum Cb value also varies with the characteristics of the bipolar transistor to be employed. Therefore, determine the optimum value through experiments. 4. Enhancement MOS FET type Figure 9 is a circuit example using Sanyo Electric Co., Ltd. MPH341 MOS FET transistor (Nchannel). For a MOS FET, an Nchannel power MOS FET should be used. Because the gate voltage and current of the external power MOS FET are supplied from the stepped up output voltage V OUT, the MOS FET is driven more effectively. Depending on the MOS FET you use in your device, there is a chance of a current overrun at power ON. Thoroughly test all settings with your device before deciding on which one to use. Also, try to use a MOS FET with the input capacitance of 7 pf or less. EXT (VDD) (ON / OFF) VSS Figure 9 Circuit example using MOS FET Since the ON resistor of the MOS FET might depend on the difference between the output voltage V OUT and the threshold voltage of MOS FET, and affect the output current as well as the efficiency, the threshold voltage should be low. When the output voltage is low, the circuit operates only when the MOS FET has the threshold voltage lower than the output voltage. Seiko Instruments Inc. 17

18 S8355/56/57/58 Series Rev V DD /V OUT separate types (E,G,J,K,L,and M type) The E, G, J, K, L, and M type are applicable to the following uses because the power pin for IC chip and pin for output voltage are separated: (1) When changing the output voltage with an external resistance. () When outputting the high voltage such as 15 V or V. Choose the products in the following table according to applications for (1) to (). Output voltage V CC 1.8 V V CC <5 V 5 V V CC Reference circuit S835xx18 Yes Yes Application circuit 1 (Figure 17) S835xx5 Yes Application circuit 1 (Figure 17) Connection to VDD pin or V CC The operational precautions are follows: 1) This IC starts to stepup operation at V DD =.8 V but set 1.8 V DD 1 V to stabilize the output voltage and frequency of the oscillator. (Input the voltage of 1.8 V or more for VDD pin for all the products of setting less than 1.9 V) The input voltage of 1.8 V or more for VDD pin allows the connection of VDD pin to either input power pin VIN or output power pin. ) Choose external resistors R A and R B not to affect to the output voltage with the consideration of the impedance between and VSS pins in the IC chip. Internal resistance between and VSS pins are as follows: (1) S835xx MΩ to 14.9 MΩ () S835xx 5. MΩ to 1.3 MΩ (3) S835xx5 3.8 MΩ to 1.4 MΩ 3) Attach the capacitor (C C ) in parallel to R A resistance when unstable action such as the oscillation of the output voltage occurs. Calculate C C from the following equatuon: C C (F) = 1 π R A khz 18 Seiko Instruments Inc.

19 Rev S8355/56/57/58 Series Standard Circuits (1) S8357BxxMA, S8357BxxUA S8358BxxMA, S8358BxxUA SD L Oscillation circuit C IN pf 1 kω EXT PWM or PWM /PFM switching control circuit Soft start builtin reference power supply IC internal power supply Phase compensating circuit VSS C L Note) The power supply for IC chip is from pin. Figure 1 Standard circuit (1) () S8357BxxMC, S8357FxxMC/BD, S8357HxxMC/BD S8358BxxMC, S8358FxxMC/BD, S8358HxxMC/BD SD L Oscillation circuit pf IC internal power supply C IN 1 kω EXT PWM or PWM /PFM switching control circuit C L Soft start builtin reference power supply Phase compensating circuit VSS Note) The power supply for IC chip is from pin. ON/OFF Figure 11 Standard circuit () (3) S8357ExxMC, S8357GxxMC/BD, S8357JxxMC/BD S8358ExxMC, S8358GxxMC/BD, S8358JxxMC/BD SD L pf Oscillation circuit VDD IC internal power supply C IN 1 kω EXT PWM or PWM /PFM switching control circuit C L Soft start builtin reference power supply Phase compensating circuit VSS Note) The power supply for IC chip is from VDD pin. Figure 1 Standard circuit (3) Seiko Instruments Inc. 19

20 S8355/56/57/58 Series Rev (4) S8357EXXMC, S8357GXXMC/BD, S8357JXXMC/BD S8358EXXMC, S8358GXXMC/BD, S8358JXXMC/BD SD L pf Oscillation circuit VDD IC internal power supply C IN 1 kω EXT PWM or PWM /PFM switching control circuit C L Soft start builtin reference power supply Phase compensating circuit VSS Note) The power supply for IC chip is from VDD pin. (5) S8355KXXMC, S8355LXXMC/BD, S8355MXXMC/BD S8356KXXMC, S8356LXXMC/BD, S8356MXXMC/BD L pf Figure 13 Standard circuit (4) SD Oscillation circuit VDD IC internal power supply C IN 1 kω EXT PWM or PWM /PFM switching control circuit C L Soft start builtin reference power supply Phase compensating circuit VSS Note) The power supply for IC chip is from VDD pin. ON/OFF Figure 14 Standard circuit (5) (6) S8355KXXMC, S8355LXXMC/BD, S8355MXXMC/BD S8356KXXMC, S8356LXXMC/BD, S8356MXXMC/BD SD L pf Oscillation circuit VDD IC internal power supply C IN 1 kω EXT PWM or PWM /PFM switching control circuit C L Soft start builtin reference power supply Phase compensating circuit VSS Note) The power supply for IC chip is from VDD pin. ON/OFF Figure 15 Standard circuit (6) Seiko Instruments Inc.

21 Rev S8355/56/57/58 Series Power Dissipation of Package Power Dissipation 6 4 SOT893 SOT35 SOT33 P D (mw) 6Pin SNB(B) Amb. Temperature Ta ( C) Figure 16 Power dissipation of the package (before mounting) Precautions Mount external capacitors, a diode, and a coil as near as possible to the IC. Unique ripple voltage and spike noise occur in switching regulators. Because they largely depend on the coil and the capacitor used, check them using an actually mounted model. Make sure dissipation of the switching transistor (especially at a high temperature) does not exceed the allowable power dissipation of the package. The performance of this IC varies depending on the PCB patterns, peripheral circuits or external parts. Thoroughly test all settings with your device. Also, try to use recommended external parts. If not, contact your sales person. Seiko Instruments Inc. shall not be responsible for any patent infringement by products including S 8355/56/57/58 Series in connection with the method of using S8355/56/57/58 Series in such products, the specification of such products, or the country of destination thereof. Seiko Instruments Inc. 1

22 S8355/56/57/58 Series Rev Application Ciruits 1. LCD Power Supply The following examples are an application power supply circuit (15 V/ V output) to drive LCD panels, and its characteristics. L SD V OUT C IN C C R A C L VDD TR ON/OFF S8356M5 EXT VSS R B Figure 17 Power supply circuit for LCD Output voltage IC L type name TR type name SD type name C L Ra Rb Cc Output characteristics (1) 15 V S8356M5 CDRH5D18 MCH345 MAZ748 F93( V,1 µf) 58 kω 3 kω 15 pf (1a),(1b) () V S8356M5 CDRH5D18 FDN337N MA79 F93(5 V,1 µf) 575 kω kω 15 pf (a),(b) 1 (1a) Output Current Efficiency 1 (a) Output Current Efficiency Efficiency η [%] =3 V =5 V =7 V Efficiency η [%] =3 V =5 V =7 V Output Voltage (1b) Output Current Output Voltage =3 V 13 =5 V =7 V Output Voltage 18 (b) Output Current Output Voltage =3 V 16 =5 V =7 V Figure 18 LCD power supply output characteristics Seiko Instruments Inc.

23 Rev S8355/56/57/58 Series. Ceramic Capacitor If using small ESR parts such as ceramic capacitors to the output capacitance, attach a resistor (R1) corresponding to the ESR in series to the ceramic capacitor (C L ) as shown in the following circuit. R1 may depend on L, capacitance, wiring and applications (output load). The follwong examples are a circuit using R1 =1 mω, output voltage =3.3 V, output load =5 ma and its characteristics. L SD V OUT C IN TR EXT R1 VSS C L Figure 19 Ceramic capacitor circuit IC L type name TR type name SD type name C L (ceramic capacitor) R1 Output characteristics (1) S8357F33 CDRH6D8 FDN335N M1FH3 1 µf pieces 1 mω (1a),(1b),(1c) () S8358B5 CDRH6D847 FDN335N M1FH3 1 µf pieces 1 mω (a),(b),(c) Seiko Instruments Inc. 3

24 S8355/56/57/58 Series Rev (1a) Output Current Efficiency 1 (a) Output Current Efficiency Efficiency η [%] Output Voltage Ripple Voltage Vr [mv] =.9 V =1.8 V =.7 V =.9 V 3.9 =1.8 V =.7 V (1b) Output Current Output Voltage (1c) Output Current Ripple Voltage =.9 V =1.8 V =.7 V Efficiency η [%] Output Voltage Ripple Voltage Vr [mv] = V =3 V =4 V = V =3 V =4 V (b) Output Current Output Voltage (c) Output Current Ripple Voltage = V =3 V =4 V Figure Ceramic capacitor circuit output characteristics 4 Seiko Instruments Inc.

25 Rev S8355/56/57/58 Series Temperature Characteristics (Ta = 4 to 85 C) 5 I SS1 Ta (V OUT=3.3 V, f osc=1 khz) 5 I SS1 Ta (V OUT=3.3V, f osc=3 khz) 4 4 I SS1 [µa] I SS1 [µa] I SS Ta (V OUT=3.3 V, f osc=1 khz) 1 I SS Ta (V OUT=3.3 V, f osc=3 khz) 8 8 I SS [µa] 6 4 I SS [µa] I SSS Ta (V OUT=3.3 V, f osc=1 khz) 1. I SSS Ta (V OUT=3.3 V, f osc=3khz).8.8 I SSS.6 [µa].4 I SSS.6 [µa] I EXTH Ta (V OUT=3.3 V, f osc=3 khz) 6 I EXTL Ta (V OUT=3.3 V, f osc=3 khz) I EXTH 3 [ma] I EXTL [ma] Seiko Instruments Inc. 5

26 S8355/56/57/58 Series Rev f OSC Ta (V OUT=3.3 V, f osc=1 khz) 4 f OSC Ta (V OUT=3.3 V, f OSC =3 khz) f OSC [khz] 1 75 f OSC [khz] MaxDuty Ta (V OUT=3.3 V, f osc=1 khz) 9 MaxDuty Ta (V OUT=3.3 V, f osc=3 khz) MaxDuty [%] 8 MaxDuty [%] PFMDuty [%] 15 1 PFMDuty Ta (=3.3 V, fosc=1 khz) S8356/58 Series V SH V SH Ta (V OUT=3.3 V, f osc=3 khz) V SL1 Ta (V OUT=3.3 V, f osc=3 khz) 1. V SL Ta (V OUT=3.3 V, f osc=3 khz).8.8 V SL1.6.4 V SL Seiko Instruments Inc.

27 Rev S8355/56/57/58 Series 8 T SS Ta (V OUT=3.3 V, f osc=1 khz) 8 T SS Ta (V OUT=3.3 V, f osc=3 khz) 6 6 T SS [ms] 4 T SS [ms] V ST1 Ta (V OUT=3.3 V, f osc=1 khz) 1. V ST Ta (V OUT=3.3 V, f osc=3 khz) V ST1.6 V ST V OUT Ta (V OUT=3.3 V, f osc=1 khz) 3.4 V OUT Ta (V OUT=3.3 V, f osc=3 khz) V OUT V OUT Seiko Instruments Inc. 7

28 S8355/56/57/58 Series Rev Characteristics of Major Items against Voltage (Ta=5 C) 5 I SS1, V DD (V OUT =3.3 V, F osc =3 khz, Ta =5 C) 1. I SSS V DD (V OUT =3.3 v, f osc =3 khz, Ta =5 C) 4.8 I SS1, [µa] 3 I SSS [µa] V DD V DD 1 f OSC V DD (f OSC =1 khz) 36 f OSC V DD (f OSC =3 khz) 1 3 f OSC 8 [khz] 6 f OSC 4 [khz] V DD V DD 1 I EXTH V DD 1 I EXTL V DD 8 8 I EXTH [ma] 6 4 I EXTL [ma] V DD V DD 3.5 V OUT V DD (V OUT=3.3 V, f OSC=1 khz, V DD separate type) =1.98 V, I OUT=66 ma 3.5 V OUT V DD (V OUT=3.3 V, f OSC=3 khz, V DD separate type) =1.98 V, I OUT=66 ma V OUT.5 V OUT V DD V DD 8 Seiko Instruments Inc.

29 Rev S8355/56/57/58 Series Output Waveform 1. S8358B33MC 1. I OUT =1 ma 3.4. I OUT = ma 3.4 Output Voltage [.5 V/div] CONT Voltage [ V/div] time [µs] Output Voltage [.5 V/div] CONT Voltage [ V/div] time [µs] I OUT =1 ma I OUT = ma 3.4 Output Voltage [.5 V/div] CONT Voltage [ V/div] time [µs] Output Voltage [.5 V/div] 4 CONT Voltage [ V/div] time [µs] S8358F33MC 1. I OUT =1 ma 3.4. I OUT =1 ma 3.4 Output Voltage [.5 V/div] 4 CONT Voltage [ V/div] time [µs] Output Voltage [.5 V/div] CONT Voltage [ V/div] time [µs] I OUT =1 ma I OUT = ma 3.4 Output Voltage [.5 V/div] CONT Voltage [ V/div] time [µs] Output Voltage [.5 V/div] CONT Voltage [ V/div] time [µs] Seiko Instruments Inc. 9

30 S8355/56/57/58 Series Rev Transient Responses 1. Powering ON ( ; V. V ) Powering ON (1 khz, I OUT =1 ma ) 4 Powering ON (1 khz, I OUT =1 ma ) 4 V OUT time [ms] time [ms] Powering ON (3 khz, I OUT =1 ma ) 4 V OUT Powering ON (3 khz, I OUT =1 ma ) time [ms] time [ms]. Responses of Shutdown pin (ON/OFF ; V. V ) V ON/OFF (1 khz, IOUT=1 ma) 4 ON/OFF (1 khz, IOUT=1 ma) 4 V OUT V ON/OFF V ON/OFF time [ms] time [ms] ON/OFF (3 khz, IOUT=1 ma) 4 ON/OFF (3 khz, IOUT=1 ma) 4 V OUT V ON/OFF V ON/OFF time [ms] time [ms] 3 Seiko Instruments Inc.

31 Rev S8355/56/57/58 Series 3. Load Fluctuations I OUT 1 ma Load Fluctuations (1 khz, I OUT; 1 µa 1 ma) 3.6 I OUT 1 ma Load Fluctuations (1 khz, I OUT; 1 ma 1 µa) µa µa 3.6 V OUT [. V/div] time [ms] V OUT [. V/div] time [ms] 3. Load Fluctuations (3 khz, I OUT; 1 µ A 1 ma) I 3.6 OUT 1 ma 1 µa 3.4 I OUT 1 ma 1 µa Load Fluctuations (3 khz, I OUT; 1 ma 1 µa) V OUT [. V/div] time [ms] V OUT [. V/div] time [ms] Power Voltage Fluctuations Power Voltage Fluctuations (1 khz, I OUT=1 ma) =1mA) =1.98 V.64 V V OUT Power Voltage Fluctuations (1 khz, I OUT=1 ma) =1mA) V = V V OUT time [ms] time [ms] 3..5 Power Voltage Fluctuations (3 khz, I OUT=1 ma) =1.98 V.64 V V OUT Power Voltage Fluctuations (3 khz, I OUT=1 ma) =.64 V 1.98 V V OUT time [ms] time [ms] Seiko Instruments Inc. 31

32 S8355/56/57/58 Series Rev Reference Data Use reference data to choose the external parts. The reference data here give you the procedure to choose the recommended external parts for various applications and its characteristics data. 1. Reference Data for External Components No. Table 1. Efficiency Output and Output Voltage Output Current characteristics for external components Product name Oscillation frequency Output voltage Control system Inductor Transister Diode Output capacitor (1) S8357F33 3 khz 3.3 V PWM CDRH14R FDN335N M1FH3 F93(16 V,47 µf) () S8357F5 3 khz 5. V PWM (3) S8356M5 3 khz 5. V PWM/PFM (4) S8357B33 1 khz 3.3 V PWM CDRH14R47 (5) S8358B33 1 khz 3.3 V PWM/PFM (6) S8357B5 1 khz 5. V PWM (7) S8356M5 3 khz 5. V PWM/PFM CDRH8D8 FDN335N M1FH3 F93(16 V,47 µf) (8) S8357B33 1 khz 3.3 V PWM CDRH8D847 (9) S8358B33 1 khz 3.3 V PWM/PFM (1) S8357B5 1 khz 5. V PWM (11) S8357F33 3 khz 3.3 V PWM CDLP1 MCH345 MAZ748 F9(6.3 V,47 µf) (1) S8356M5 3 khz 5. V PWM/PFM The properties of external parts are shown below. Table. Properties of external parts Part Product name Manufacturer Characteristics CDRH14R µh, DCR 1) =93 mω, Imax ) =.9 A, Height =4. mm CDRH14R47 47 µh, DCR 1) =18 mω, Imax ) =.1 A, Height =4. mm Sumida Corporation CDRH8D8 µh, DCR 1) =95 mω, Imax ) =1.6 A, Height =3. mm Inductor CDRH8D µh, DCR 1) =19 mω, Imax ) =1.15 A, Height =3. mm CXLP1 Sumitomo Special Metals Co., Ltd. µh, DCR 1) =59 mω, Imax ) =.55 A, Height =1. mm Diode M1FH3 Shindengen Electric Manufacturing Co., Ltd. V 3) 4) F =.3V, I F =1.5 A MAZ748 Matsushita Electric Industrial Co., Ltd. V 3) 4) F =.4V, I F =.3 A Capacitor F93 16 V, 47 µf (Output Nichicon Corporation F9 capacitance) 6.3 V, 47 µf Transister (Nch FET) FDN335N MCH345 FairchildSemiconductor Japan Ltd. Sanyo Electric Co., Ltd. Vdss 5) = Vmax, Vgss 6) =8 Vmax, Ciss 7) =31 pf, Id 8) =1.5 A (Vgs 9) =.5 V) Vdss 5) = Vmax, Vgss 6) =1 Vmax, Ciss 7) =8 pf, Id 8) =.5 A (Vgs 9) =1.8 V) 1) : DC resistance, ) : Max allowable current, 3) : Forward voltage, 4) : Forward current, 5) : Drainsource voltage, 6) : Gatesource voltage, 7) : Input capacitance, 8) : Drain current, 9) : Gatesource voltage 3 Seiko Instruments Inc.

33 Rev S8355/56/57/58 Series. Reference Data 1 The data of (a) efficiency characteristics for output current and (b) output voltage characteristics for output current under conditions of (1) to (1) shown in Table 1 are shown below. (1) S8357F33 Efficiency η [%] (a) Output CurrentEfficiency 4 =.9 V =1.8 V =.7 V Output Voltage (b) Output CurrentOutput Voltage 3. =.9 V 3.1 =1.8 V =.7 V () S8357F5 1 (a) Output CurrentEfficiency 5. (b) Output CurrentOutput Voltage Efficiency η [%] = V =3 V =4 V Output Voltage = V 4.8 =3 V =4 V (3) S8356M5 Efficiency η [%] (a) Output CurrentEfficiency V 4 IN = V =3 V =4 V Output Voltage (b) Output CurrentOutput Voltage 4.9 = V 4.8 =3 V =4 V Seiko Instruments Inc. 33

34 S8355/56/57/58 Series Rev (4) S8357B33 Efficiency η [%] (a) Output CurrentEfficiency V 4 IN =.9 V =1.8 V =.7 V Output Voltage (b) Output CurrentOutput Voltage 3. =.9 V 3.1 =1.8 V =.7 V (5) S8358B33 Efficiency η [%] (a) Output CurrentEfficiency V 4 IN =.9 V =1.8 V =.7 V Output Voltage (b) Output CurrentOutput Voltage 3. =.9 V 3.1 =1.8 V 3. =.7 V (6) S8357B5 Efficiency η [%] (a) Output CurrentEfficiency V 4 IN = V =3 V =4 V Output Voltage (b) Output CurrentOutput Voltage 4.9 = V 4.8 =3 V =4 V Seiko Instruments Inc.

35 Rev S8355/56/57/58 Series (7) S8356M5 Efficiency η [%] (a) Output CurrentEfficiency V 4 IN = V =3 V =4 V Output Voltage (b) Output CurrentOutput Voltage 4.9 = V 4.8 =3 V =4 V (8) S8357B33 Efficiency η [%] (a) Output CurrentEfficiency 4 =.9V =1.8V =.7V Output Voltage (b) Output CurrentOutput Voltage 3. =.9 V 3.1 =1.8 V =.7 V (9) S8358B33 Efficiency η [%] (a) Output CurrentEfficiency 4 =.9 V =1.8 V =.7 V Output Voltage (b) Output CurrentOutput Voltage 3. =.9 V 3.1 =1.8 V =.7 V Seiko Instruments Inc. 35

36 S8355/56/57/58 Series Rev (1) S8357B5 Efficiency η [%] (a) Output CurrentEfficiency V 4 IN = V =3 V =4 V Output Voltage (b) Output CurrentOutput Voltage 4.9 = V 4.8 =3 V =4 V (11) S8357F33 Efficiency η [%] (a) Output CurrentEfficiency 4 IN =.9V IN =1.8V IN =.7V Output Voltage (b) Output CurrentOutput Voltage 3. IN =.9V 3.1 IN =1.8V IN =.7V (1) S8356M5 (a) Output CurrentEfficiency (b) Output CurrentOutput Voltage Efficiency η [%] V 4 IN = V =3 V =4 V Output Voltage = V 4.8 =3 V =4 V Seiko Instruments Inc.