ULTRA-SMALL PACKAGE PWM CONTROL, PWM/PFM S-8353/8354

Transcription

1 Rev.1._ ULTRA-SMALL PACKAGE PWM CONTROL, PWM/PFM SWITCHING CONTROL STEP-UP SWITCHING REGULATOR The is a CMOS step-up switching regulator which mainly consists of a reference voltage source, an oscillation circuit, a power MOS FET, an error amplifier, a phase compensation circuit, a PWM controller (S-8353 Series) and a PWM/PFM switching controller (S-8354 Series). Simply attaching a coil, capacitor, and diode externally can configure the step-up switching regulator. In addition to the above features, the small package and low power consumption of this series make it ideal for portable device applications requiring high efficiency. The S-8353 Series realizes low ripple, high efficiency, and excellent transient characteristics due to its PWM controller, which can vary the duty ratio linearly from % to 83 % (from % to 78 % for 5 khz models), optimally-designed error amplifier, and phase compensation circuits. The S-8354 Series features a PWM/PFM switching controller that can switch the operation to a PFM controller with a duty ratio is 15 % under a light load to prevent a decline in the efficiency due to the IC operating current. Features Low voltage operation: Low current consumption: Duty ratio: External parts: Output voltage: Oscillation frequency: Soft start function: Start-up is guaranteed from.9 V (I OUT =1 ma) During operation: 18.7 µa (3.3 V, 5 khz, typ.) During shutdown:.5 µa (max.) Built-in PWM/PFM switching control circuit (S-8354 Series) 15 % to 83 % (3 khz and 5 khz models), 15 % to 78 % (5 khz models) Coil, capacitor, and diode Can be set in.1 V steps 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%. 3 khz, 5 khz, and 5 khz 6 ms (5 khz, typ.) 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 Packages Package name Drawing code Package Tape Reel SOT-3-3 MP3-A MP3-A MP3-A SOT-3-5 MP5-A MP5-A MP5-A SOT-89-3 UP3-A UP3-A UP3-A Seiko Instruments Inc. 1

2 Rev.1._ Block Diagrams 1. A, C, H type (Without Shutdown Function) CONT VOUT Oscillation circuit PWM control, PWM/PFM switching control circuit Soft start built-in reference power supply IC internal power supply + Phase compensation circuit VSS Figure 1. A, H type (With Shutdown Function) CONT VOUT Oscillation circuit IC internal power supply PWM control, + PWM/PFM switching control circuit Soft start built-in reference power supply Phase compensation circuit VSS ON / OFF Figure 3. D, J type CONT VDD VOUT Oscillation circuit PWM control, PWM/PFM switching control circuit Soft start built-in reference power supply IC internal power supply Phase compensation circuit + VSS Figure 3 Seiko Instruments Inc.

3 Rev.1. _ Product Name Structure 1. Function List Product name Control system Switching frequency [khz] Shutdown function Table 1 V DD /V OUT separate type Package Application S-8353AxxMC PWM 5 Yes Application requiring shutdown SOT-3-5 function S-8353AxxMA PWM 5 Application not requiring shutdown SOT-3-3 function S-8353AxxUA PWM 5 Application not requiring shutdown SOT-89-3 function S-8353CxxMA PWM 3 SOT-3-3 For pager S-8353DxxMC PWM 5 Yes Application in which output voltage SOT-3-5 is adjusted by external resistance S-8353HxxMC PWM 5 Yes Application requiring shutdown SOT-3-5 function and thin coil S-8353HxxMA PWM 5 Application not requiring shutdown SOT-3-3 function and requiring thin coil S-8353HxxUA PWM 5 Application not requiring shutdown SOT-89-3 function and requiring thin coil S-8353JxxMC PWM 5 Yes Application in which output voltage SOT-3-5 is adjusted by external resistance and that requires thin coil S-8354AxxMC PWM/PFM Application requiring shutdown 5 Yes SOT-3-5 switching function S-8354AxxMA PWM/PFM Application not requiring shutdown 5 SOT-3-3 switching function S-8354AxxUA PWM/PFM Application not requiring shutdown 5 SOT-89-3 switching function S-8354CxxMA PWM/PFM switching 3 SOT-3-3 For pager S-8354DxxMC PWM/PFM Application in which output voltage 5 Yes SOT-3-5 switching is adjusted by external resistance S-8354HxxMC PWM/PFM Application requiring shutdown 5 Yes SOT-3-5 switching function and thin coil S-8354HxxMA PWM/PFM Application not requiring shutdown 5 SOT-3-3 switching function and requiring thin coil S-8354HxxUA PWM/PFM Application not requiring shutdown 5 SOT-89-3 switching function and requiring thin coil S-8354JxxMC Application in which output voltage PWM/PFM 5 Yes SOT-3-5 is adjusted by external resistance switching and that requires thin coil Seiko Instruments Inc. 3

4 Rev.1._. Product Name S-835 x x xx xx - xxx - T IC direction in tape specifications *1 Product code * Package code MA: SOT-3-3 MC: SOT-3-5 UA: SOT-89-3 Output voltage 15 to 65 (Ex. When the output voltage is 1.5 V, it is expressed as 15.) Product type A: Normal products (SOT3-3, SOT-89-3), f osc =5 khz or With shutdown function products (SOT-3-5), f osc =5 khz C: Normal products f osc =3 khz D: V DD /V OUT separate type, f osc =5 khz H: Normal products (SOT3-3, SOT-89-3), f osc =5 khz or With shutdown function products (SOT-3-5), f osc =5 khz J: V DD /V OUT separate type, f osc =5 khz Control system 3: PWM control 4: PWM/PFM control *1. Refer to the taping specifications at the end of this book. *. Refer to the 3. Product Name List. 4 Seiko Instruments Inc.

5 Rev.1. _ 3. Product Name List 3-1. S-8353 Series Table Output voltage S-8353AxxMC Series S-8353AxxMA Series S-8353AxxUA Series S-8353CxxMA Series. V S-8353AMC-IQF-T.5 V S-8353A5MC-IQK-T.7 V S-8353A7MC-IQM-T.8 V S-8353A8MC-IQN-T 3. V S-8353A3MC-IQP-T S-8353A3MA-IQP-T S-8353C3MA-ISP-T 3.3 V S-8353A33MC-IQS-T S-8353A33MA-IQS-T S-8353A33UA-IQS-T 3.8 V S-8353A38MC-IQX-T 5. V S-8353A5MC-IRJ-T S-8353A5MA-IRJ-T S-8353A5UA-IRJ-T Remark Please contact the SII marketing department for products with an output voltage other than those specified above. Table 3 Output voltage S-8353DxxMC Series S-8353HxxMC Series S-8353JxxMC Series. V S-8353DMC-IUF-T S-8353JMC-IYF-T.5 V S-8353J5MC-IYK-T 3. V S-8353D3MC-IUP-T S-8353H3MC-IWP-T 3.1 V S-8353H31MC-IWQ-T 3.3 V S-8353H33MC-IWS-T 3.8 V S-8353H38MC-IWX-T 4. V S-8353H4MC-IWZ-T 4.5 V S-8353H45MC-IXE-T 5. V S-8353D5MC-IVJ-T S-8353H5MC-IXJ-T S-8353J5MC-IZJ-T Remark Please contact the SII marketing department for products with an output voltage other than those specified above. 3-. S-8354 Series Table 4 Output voltage S-8354AxxMC Series S-8354AxxMA Series S-8354AxxUA Series S-8354DxxMC Series. V S-8354DMC-JUF-T.7 V S-8354A7MC-JQM-T S-8354A7MA-JQM-T 3. V S-8354A3MC-JQP-T S-8354A3MA-JQP-T S-8354A3UA-JQP-T 3.3 V S-8354A33MC-JQS-T S-8354A33MA-JQS-T S-8354A33UA-JQS-T 4. V S-8354A4MC-JQZ-T 5. V S-8354A5MC-JRJ-T S-8354A5MA-JRJ-T S-8354A5UA-JRJ-T Remark Please contact the SII marketing department for products with an output voltage other than those specified above. Table 5 Output voltage S-8354HxxMC Series S-8354JxxMC Series 3. V S-8354H3MC-JWP-T 3.3 V S-8354H33MC-JWS-T 5. V S-8354H5MC-JXJ-T S-8354J5MC-JZJ-T Remark Please contact the SII marketing department for products with an output voltage other than those specified above. Seiko Instruments Inc. 5

6 Rev.1._ Pin Configurations SOT-3-3 Top view 1 Table 6 Pin No. Symbol Pin description 1 VOUT Output voltage and IC power supply pin VSS GND pin 3 CONT External inductor connection pin 3 Figure 4 SOT-3-5 Top view 5 4 Table 7 Pin No. Symbol Pin description 1 ON / OFF (A, H type) Shutdown pin H : Normal operation (Step-up operation) L : Stop step-up (Entire circuit stopped) VOUT Output voltage pin (D, J type) VOUT Output voltage and IC power supply pin (A, H type) 1 3 VDD IC power supply pin (D, J type) 3 NC *1 No connection Figure 5 4 VSS GND pin 5 CONT External inductor connection pin *1. The NC pin is electrically open. SOT-89-3 Top view Table 8 Pin No. Symbol Pin description 1 VSS GND pin VOUT Output voltage and IC power supply pin 3 CONT External inductor connection pin 1 3 Figure 6 6 Seiko Instruments Inc.

7 Rev.1. _ Absolute Maximum Ratings Table 9 (Ta=5 C unless otherwise specified) Item Symbol Absolute maximum rating Unit VOUT pin voltage V OUT V SS.3 to V SS +1 V ON / OFF pin voltage (S-835xAxxMC, S-835xHxxMC) V ON / OFF V SS.3 to V SS +1 VDD pin voltage (S-835xDxxMC, S-835xJxxMC) V DD V SS.3 to V SS +1 CONT pin voltage V CONT V SS.3 to V SS +1 CONT pin voltage I CONT 3 ma Power dissipation P D SOT mw SOT SOT Operating ambient temperature Topr 4 to +85 C Storage ambient temperature Tstg 4 to +15 Caution The absolute maximum ratings are rated values exceeding which the product cloud suffer physical damage. These values must therefore not be exceeded under any conditions. Seiko Instruments Inc. 7

8 Rev.1._ Electrical Characteristics 1. 5 khz Product (A type, D type) Table 1 (Ta=5 C unless otherwise specified) Item Symbol Condition Min. Typ. Max. Unit Test circuit Output voltage V OUT V OUT(S) V OUT(S) V OUT(S) V Input voltage V IN 1 Operation start voltage V ST1 I OUT =1 ma.9 Oscillation start voltage V ST No external parts, Voltage applied to V OUT.8 1 Operation holding voltage V I OUT =1 ma, Measured by decreasing V IN HLD voltage gradually.7 Current consumption 1 I SS1 V OUT =V OUT(S).95 S-835xx15 to µa 1 S-835xx to S-835xx3 to S-835xx4 to S-835xx5 to S-835xx6 to Current consumption I SS V OUT =V OUT(S) +.5 S-835xx15 to S-835xx to S-835xx3 to S-835xx4 to S-835xx5 to S-835xx6 to Current consumption during shutdown (S-835xAxxMC Series) I SSS V ON / OFF = V.5 Switching current I SW V CONT =.4 V S-835xx15 to ma S-835xx to S-835xx5 to 9 15 S-835xx3 to S-835xx4 to S-835xx5 to 59 3 S-835xx6 to Switching transistor leak current I SWQ V CONT =V OUT =1 V.5 µa Line regulation V OUT1 V IN =V OUT(S).4 to mv Load regulation V OUT I OUT =1 µa to V OUT(S) / Output voltage VOUT ppm/ temperature coefficient Ta= 4 C ~ +85 C ±5 Ta VOUT C Oscillation frequency f OSC V OUT =V OUT(S) khz 1 Maximum Duty ratio MaxDuty V OUT =V OUT(S) % PWM/PFM switching duty ratio (S-8354 Series) ON / OFF pin input voltage (S-835xAxxMC Series) PFMDuty V IN =V OUT(S).1 V, No load V SH Measured oscillation at CONT pin.75 V V SL1 Judged the stop When V OUT 1.5 V.3 oscillation at CONT V SL pin When V OUT <1.5 V. ON / OFF pin input current I SH ON / OFF pin=v OUT(S) µa (S-835xAxxMC Series) I SL ON / OFF pin= V.1.1 Soft start time t SS ms Efficiency EFFI 85 % 8 Seiko Instruments Inc.

9 Rev.1. _ External parts Coil: CDRH6D8-11 of Sumida Corporation Diode: MAZ748 (Shottky type) of Matsushita Electric Industrial Co., Ltd. Capacitor: F93 (16 V, µf tantalum type) of Nichicon Corporation V IN =V OUT(S).6 applied, I OUT =V OUT(S) / 5Ω Shutdown function built-in type (S-835xAxxMC Series): ON / OFF pin is connected to V OUT V DD /V OUT separate type (S-835xDxxMC Series): VDD pin is connected to VOUT pin Remarks 1. V OUT(S) specified above is the set output voltage value, and V OUT is the typical value of the actual output voltage.. V DD /V OUT separate type: Step-up operation is performed from V DD =.8 V. However, 1.8 V V DD <1 V is recommended to stabilize the output voltage and oscillation frequency. (V DD 1.8 V must be applied for products with a set value of less than 1.9 V.) Seiko Instruments Inc. 9

10 Rev.1._. 3 khz Product (C type) Table 11 (Ta=5 C unless otherwise specified) Item Symbol Condition Min. Typ. Max. Unit Test circuit Output voltage V OUT V OUT(S) V OUT(S) V OUT(S) V Input voltage V IN 1 Operation start voltage V ST1 I OUT =1 ma.9 Oscillation start voltage V ST No external parts, Voltage applied to V OuT.8 1 Operation holding voltage V I OUT =1 ma, Measured by decreasing V IN HLD voltage gradually.7 Current consumption 1 I SS1 V OUT =V OUT(S).95 S-835xx to µa 1 S-835xx3 to S-835xx4 to S-835xx5 to S-835xx6 to Current consumption I SS V OUT =V OUT(S) +.5 S-835xx to S-835xx3 to S-835xx4 to S-835xx5 to S-835xx6 to Switching current I SW V CONT =.4 V S-835xx to ma S-835xx5 to S-835xx3 to S-835xx4 to S-835xx5 to S-835xx6 to Switching transistor leak current I SWQ V CONT =V OUT =1 V.5 µa Line regulation V OUT1 V IN =V OUT(S).4 to mv Load regulation V OUT I OUT =1 µa to V OUT(S) / Output voltage VOUT ppm/ temperature coefficient Ta= 4 C to +85 C ±5 Ta VOUT C Oscillation frequency f OSC V OUT =V OUT(S) khz 1 Maximum duty ratio MaxDuty V OUT =V OUT(S) % PWM/PFM switching duty ratio (S-8354 Series) PFMDuty V IN =V OUT(S).1 V, No load Soft start time t SS ms Efficiency EFFI 84 % External parts Coil: CDRH6D8-11 of Sumida Corporation Diode: MAZ748 (Shottky type) of Matsushita Electric Industrial Co., Ltd. Capacitor: F93 (16 V, µf tantalum type) of Nichicon Corporation V IN =V OUT(S).6 applied, I OUT =V OUT(S) / 5Ω Remarks 1. V OUT(S) specified above is the set output voltage value, and V OUT is the typical value of the actual output voltage. 1 Seiko Instruments Inc.

11 Rev.1. _ 3. 5 khz Product (H type, J type) Table 1 (Ta=5 C unless otherwise specified) Item Symbol Condition Min. Typ. Max. Unit Test citcuit Output voltage V OUT V OUT(S) V OUT(S) V OUT(S) V Input voltage V IN 1 Operation start voltage V ST1 I OUT =1 ma.9 Oscillation start voltage V ST No external parts, Voltage applied to V OUT.8 1 Operation holding voltage V I OUT =1 ma, Measured by decreasing V IN HLD gradually.7 Current consumption 1 I SS1 V OUT =V OUT(S).95 S-835xx15 to µa 1 S-835xx to S-835xx3 to S-835xx4 to S-835xx5 to S-835xx6 to Current consumption I SS V OUT =V OUT(S) +.5 S-835xx15 to S-835xx to S-835xx3 to S-835xx4 to S-835xx5 to S-835xx6 to Current consumption during shutdown (S-835xHxxMC Series) I SSS V ON / OFF = V.5 Switching current I SW V CONT =.4 V S-835xx15 to ma S-835xx to S-835xx5 to 9 15 S-835xx3 to S-835xx4 to S-835xx5 to 59 3 S-835xx6 to Switching transistor leak current I SWQ V CONT =V OUT =1 V.5 µa Line regulation V OUT1 V IN =V OUT(S).4 to mv Load regulation V OUT I OUT =1 µa to V OUT(S) / Output voltage VOUT ppm/ temperature coefficient Ta= 4 C to +85 C ±5 Ta VOUT C Oscillation frequency f OSC V OUT =V OUT(S) khz 1 Maximum duty ratio MaxDuty V OUT =V OUT(S) % PWM/PFM switching duty ratio (S-8354 Series) ON / OFF pin input voltage (S-835xHxxMC Series) PFMDuty V IN =V OUT(S).1 V, No load V SH Measured the oscillation at CONT pin.75 V V SL1 Judged the stop of When V OUT 1.5 V.3 V SL oscillation at CONT pin When V OUT <1.5 V. ON / OFF pin input current I SH ON / OFF pin=v OUT(S) µa (S-835xHxxMC Series) I SL ON / OFF pin= V.1.1 Soft start t SS ms Efficiency EFFI 85 % Seiko Instruments Inc. 11

12 Rev.1._ External parts Coil: CDRH6D8- of Sumida Corporation Diode: MAZ748 (Shottky type) of Matsushita Electric Industrial Co., Ltd. Capacitor: F93 (16 V, µf tantalum type) of Nichicon Corporation V IN =V OUT(S).6 applied, I OUT =V OUT(S) / 5Ω Shutdown function built-in type (S-835xHxxMC Series): ON / OFF pin is connected to V OUT V DD /V OUT separate type (S-835xJxxMC Series): VDD pin is connected to VOUT pin Remarks 1. V OUT(S) specified above is the set output voltage value, and V OUT is the typical value of the actual output voltage.. V DD /V OUT separate type: Step-up operation is performed from V DD =.8 V. However, 1.8 V V DD <1 V is recommended to stabilize the output voltage and oscillation frequency. (V DD 1.8 V must be applied for products with a set value of less than 1.9 V.) 1 Seiko Instruments Inc.

13 Rev.1. _ Test Circuits 1. 3Ω CONT *1 ON / OFF VSS VOUT VDD * +.1 µf A Oscilloscope Figure 7. + CONT VOUT VDD * *1 ON / OFF VSS + V.1 µf Figure 8 *1. Only for S-835xAxxMC Series and S-835xHxxMC Series *. Only for S-835xDxxMC Series and S-835xJxxMC Series Seiko Instruments Inc. 13

14 Rev.1._ Operation 1. Step-up DC-DC Converter The S-8353 Series is a DC-DC converter that uses a pulse width modulation method (PWM) and features low current consumption. In the S-8353 Series, the switching frequency does not change, although the pulse width changes from % to 83 % (78 % for H type and J type) corresponding to each load current. The ripple voltage generated from switching can thus be removed easily using a filter because the switching frequency is constant. The S-8354 Series is a DC-DC converter that automatically switches between a pulse width modulation method (PWM) and a pulse frequency modulation method (PFM), depending on the load current, and features low current consumption. The S-8354 Series operates under PWM control with the pulse width duty changing from 15 % to 83 % (78 % for H type and J type) when the output load current is high. On the other hand, when the output current is low, the S-8354 Series operates under PFM control with the pulse width duty fixed at 15 %, and pulses are skipped according to the load current. The oscillator thus oscillates intermittently so that the resultant lower current consumption prevents a reduction in the efficiency when the load current is low. The switching point from PWM control to PFM control depends on the external devices (coil, diode, etc.), input voltage, and output voltage. This series is an especially efficient DC-DC converter at an output current of around 1 µa. For this IC, a built-in soft start circuit controls the rush current and overshoot of the output voltage when the power is turned on or the ON / OFF pin is set to H level.. ON/ OFF Pin (Shutdown Pin) (Only for S-835xAxxMC Series and S-835xHxxMC Series) Stops or starts step-up operation. Setting the ON / OFF pin to L level stops operation of all the internal circuits and reduces the current consumption significantly. DO NOT use the ON / OFF pin in a floating state because it has the structure shown in Figure 9 and is not pulled up or pulled down internally. DO NOT apply a voltage of between.3 V and.75 V to the ON / OFF pin because applying such a voltage increases the current consumption. If the ON / OFF pin is not used, connect it to the VOUT pin. The ON / OFF pin does not have hysteresis. Table 13 ON / OFF pin CR oscillation circuit Outpu voltage H Operation Fixed L Stop *1 V IN *1. Voltage obtained by extracting the voltage drop due to the DC resistance of the inductor and the diode forward voltage from V IN. VOUT ON / OFF VSS Figure 9 ON/ OFF Pin Structure 14 Seiko Instruments Inc.

15 Rev.1. _ 3. Step-up Switching Regulator Circuit for Basic Equations V IN L D CONT VOUT M1 VSS + C L Caution The above connection diagram will not guarantees successful operation. Perform through evaluation using the actual application to set the constant. Figure 1 Step-up switching regulator circuit for basic equations The following are the basic equations {(1) through (7)} of the step-up switching regulator. (Refer to Figure 1) Voltage at CONT pin at the moment M1 is turned ON, V *1 A : * V A =V S *1. Current (I L ) flowing through L is zero *. Non-saturated voltage of M1 The change in I L over time: dil VL VIN VS = = () dt L L Integration of equation () (I L ): VIN VS IL = t (3) L I L flows while M1 is ON (t ON ). The time of t ON is determined by the oscillation frequency of OSC. The peak current (I PK ) after t ON : VIN VS I PK = ton (4) L The energy stored in L is represented by 1/ L (I PK ). When M1 is turned OFF (t OFF ), the energy stored in L is emitted through a diode to the output capacitor. Then, the reverse voltage (V L ) is generated: V L =(V OUT +V *1 D ) V IN (5) *1. 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 : dil VL VOUT + VD VIN = = (6) dt L L (1) Seiko Instruments Inc. 15

16 Rev.1._ Integration of equation (6) is as follows: VOUT + VD VIN IL = IPK t (7) L During t ON, the energy is stored in L and is not transmitted to V OUT. When receiving the 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 rapidly. V OUT is a time function, and therefore indicates the maximum value (ripple voltage: V P P ) when the current flowing through into V OUT and load current (I OUT ) match. Next, the ripple voltage is determined 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: VOUT + VD VIN I OUT = IPK t1 (8) L L t 1 = (IPK IOUT) (9) VOUT + VD VIN When M1 is turned OFF (t OFF ), I L = (when the energy of the inductor is completely transmitted): Based on equation (7), L toff = VOUT + VD VIN IPK (1) When substituting equation (1) for equation (9), IOUT t 1 = toff toff (11) IPK Electric charge Q 1 which is charged in C L during t 1 : t1 t1 VOUT + VD VIN t1 VOUT + VD VIN 1 Q1 = ILdt IPK dt tdt IPK t1 t1 = = L (1) L When substituting equation (1) for equation (9): 1 IPK + IOUT Q 1 = IPK (IPK IOUT) t1 = t1 (13) A rise in voltage (V P P ) due to Q 1: Q1 1 IPK + IOUT V P P = = t1 (14) CL CL When taking into consideration I OUT to be consumed during t 1 and the ESR (Equivalent Series Resistance) of C L, namely R ESR : Q1 1 IPK + IOUT IPK + IOUT IOUT t1 VP P = = t1+ RESR (15) CL CL CL When substituting equation (11) for equation (15): V (IPK IOUT) toff IPK + IOUT P P = + RESR (16) PK L I C 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. 16 Seiko Instruments Inc.

17 Rev.1. _ External Parts Selection for DC-DC Converter The relationship between the major characteristics of the step-up circuit and the characteristic parameters of the external parts is shown in Figure 11. For larger output current? For higher efficiency? PFM control PWM control For smaller ripple voltage? Smaller inductance Larger inductance Smaller DC resistance of inductor Larger output capacitance Larger output capacitance Figure 11 Relationship between Major Characteristics of Step-up Circuit and External Parts 1. Inductor The inductance has a strong influence on the maximum output current (I OUT ) and efficiency (η). The peak current (I PK ) increases by decreasing L and the stability of the circuit improves and I OUT increases. If L is made even smaller, the efficiency falls causing a decline in the current drive capacity for the switching transistor, and I OUT decreases. The loss of I PK by the switching transistor decreases by increasing L and the efficiency becomes maximum at a certain L value. Increasing L further decreases the efficiency due to the loss of coil DC resistance. I OUT also decreases. A higher oscillation frequency allows selection of a lower L value, making the coil smaller. The recommended inductances are 47 to µh for A, C, and D types, and 1 to 47 µh for H and J types. Observe the allowable inductor current when choosing an inductor. Exceeding the allowable current of the inductor causes magnetic saturation, resulting in very low efficiency and destruction of the IC chip due to a large current. Choose an inductor so that I PK does not exceed the allowable current. I PK in con-continuous mode is calculated from the following equation: IOUT (VOUT + VD VIN) IPK = (A) (17) fosc L f osc =oscillation frequency, V D.4 V.. 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 Seiko Instruments Inc. 17

18 Rev.1._ 3. Capacitor (C IN, C L ) A capacitor on 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 on the output side (C L ) is used for smoothing the output voltage. For step-up types, the output voltage flows intermittently to the load current, so step-up types need a larger capacitance than step-down types. Therefore, select an appropriate capacitor in accordance with the ripple voltage, which increases in the case of a high output voltage or a high load current. The capacitor value should be at least 1 µf. Select capacitor with an appropriate ESR (Equivalent Series Resistance) for stable output voltage. The stable range of voltage for this IC depends on the ESR. Although the inductance (L) is also a factor, an ESR of 3 mω to 5 mω maximizes the characteristics. However, the best ESR value may depend on the value of L, the capacitance, the wiring, and the applications (output load). Therefore, fully evaluate the ESR under the actual operating conditions to determine the best value. Figure 18 of Application Circuits shows an example of a circuit that uses a ceramic capacitor and the external resistance (ESR) for reference. 4. V DD /V OUT Separate Types (Only for D type and J type) The D and J types are ideal for the following applications because the power pin for the IC chip and the VOUT pin for the output voltage are separated. (1) When changing the output voltage with external resistance. () When outputting a high voltage within the operating voltage (1 V). Choose the products in the Table 14 according to the applications (1) or () above. Table 14 Output voltage V CC 1.8 V V CC <5 V 5 V V CC 1 V S-835xx18 Yes S-835xx5 Yes Connection to VDD pin V IN or V CC V IN Cautions 1. This IC starts a step-up 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 a voltage of 1.8 V or more at the VDD pin for all products with a setting less than 1.9 V.) An input voltage of 1.8 V or more at the VDD pin allows connection of the VDD pin to either the input power VIN pin or output power VOUT pin.. Choose external resistors R A and R B so as to not affect the output voltage, considering that there is impedance between the VOUT pin and VSS pin in the IC chip. The internal resistance between the VOUT pin and VSS pin is as follows: (1) S-835xx18:.1 MΩ to 14.8 MΩ () S-835xx: 1.4 MΩ to 14.8 MΩ (3) S-835xx3: 1.4 MΩ to 14. MΩ (4) S-835xx5: 1.4 MΩ to 1.1 MΩ 3. Attach a capacitor (C C ) in parallel to the R A resistance when an unstable event such as oscillation of the output voltage occurs. Calculate C C using the following equation: 1 CC [ F] = π RA khz 18 Seiko Instruments Inc.

19 Rev.1. _ Standard Circuits 1. S-8353AxxMA/UA, S-8353CxxMA, S-8353HxxMA/UA, S-8354AxxMA/UA, S-8354CxxMA, S-8354HxxMA/UA SD V IN C IN + L CONT Oscillation circuit PWM control, PWM/PFM switching control circuit Soft start built-in reference power supply IC internal power supply + Phase compensating circuit VOUT VSS + C L Remark The power supply for the IC chip is from the VOUT pin. Figure 1. S-8353AxxMC, S-8353HxxMC, S-8354AxxMC, S-8354HxxMC V IN C IN + L CONT SD Oscillation circuit PWM control, PWM/PFM switching control circuit Soft start built-in reference power supply IC internal power supply + Phase compensating circuit VOUT VSS + C L ON / OFF Remark The power supply for the IC chip is from the VOUT pin. Figure 13 Seiko Instruments Inc. 19

20 Rev.1._ 3. S-8353DxxMC, S-8353JxxMC, S-8354DxxMC, S-8354JxxMC V IN C IN + L CONT SD Oscillation circuit PWM control, PWM/PFM switching control circuit VDD IC internal power supply + VOUT C C R A + C L Soft start built-in reference power supply Phase compensating circuit VSS R B Remark The power supply for the IC chip is from the VOUT pin. Figure 14 Caution The above connection diagram will not guarantees successful operation. Perform through evaluation using the actual application to set the constant. Seiko Instruments Inc.

21 Rev.1. _ Power Dissipation of Package Power dissipation (P D ) [mw] 6 4 SOT-89-3 SOT-3-5 SOT Ambient temperature (Ta) [ C] Figure 15 Power Dissipation of Package (Before Mounting) Precautions Mount external capacitors, diodes, and coils as close as possible to the IC. Especially, mounting the output capacitor (capacitor between VDD pin and VSS pin for V DD /V OUT separate type) in the power supply line of the IC close to the IC can enable stable output characteristics. If it is impossible, it is recommended to mount and wire a ceramic capacitor of around.1 µf close to the IC. Characteristics ripple voltage and spike noise occur in IC containing switching regulators. Moreover rush current flows at the time of a power supply injection. Because these largely depend on the coil, the capacitor and impedance of power supply used, fully check them using an actually mounted model. The performance of this IC varies depending on the design of the PCB patterns, peripheral circuits and external parts. Thoroughly test all settings with your device. The recommended external part should be used wherever possible, but if this is not possible for some reason, contact an SII sales person. Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in electrostatic protection circuit. SII claims no responsibility for any and all disputes arising out of or in connection with any infringement of the products including this IC upon patents owned a third party. Seiko Instruments Inc. 1

22 Rev.1._ Application Circuits Example of Ceramic Capacitor Application When using a component with a small ESR, such as a ceramic capacitor, for the output capacitance, mount a resistor (R 1 ) equivalent to the ESR in series with the ceramic capacitor (C L ) as shown in Figure 16. R1 differs depending on the L value, capacitance, wiring, and application (output load). The following example shows a circuit using R 1 =1 mω, output voltage=3.3 V, output load=1 ma and its characteristics. L SD V OUT V IN C IN CONT VOUT R 1 VSS C L Caution The above connection diagram and constant will not guarantees successful operation. Perform through evaluation using the actual application to set the constant. Figure 16 Circuit Using Ceramic Capacitor Table 15 IC L type name SD type name C L (Ceramic capacitor) R 1 Output Characteristics S-8353A33 CDRH5D8-11 MAZ748 1 µf 1 mω (a), (b), (c) Ceramic Capacitor Circuit Output Characteristics 1. Output current-efficiency. Output current-output voltage Efficiency η [%] V IN=.9 V IN=1.8 V IN= Output current-ripple voltage 14 1 V IN=.9 V IN=1.8 1 V IN=.7 8 Ripple voltage Vr [mv] Seiko Instruments Inc. Output voltage VOUT [V] V IN=.9 V IN=1.8 V IN=

23 Rev.1. _ Examples of Major Temperature Characteristics (Ta= = 4 to +85 C) I SS1 T a (V OUT= 3.3 V, f osc= 5 khz) I SS1 T a (V OUT= 3.3 V, f osc= 5 khz) 5 1 I SS1 4 3 [µa] T a [ C] 1 8 I SS T a (V OUT= 3.3 V, f osc= 5 khz) I SS1 8 6 [µa] T a [ C] 1 8 I SS T a (V OUT= 3.3 V, f osc= 5 khz) I SS 6 [µa] 4 I SSS [µa] T a [ C] I SSS T a (V OUT= 3.3 V, f osc= 5 khz) I SS [µa] T a [ C] I SW [ma] T a [ C] I SW T a (V OUT= 3.3 V,f osc= 5 khz) I SWQ [µa].4. I SWQ T a (V OUT= 3.3 V,f osc= 5 khz) T a [ C] T a [ C] Seiko Instruments Inc. 3

24 Rev.1._ 7 f osc T a (V OUT= 3.3 V, f osc= 5 khz) 35 f osc T a (V OUT= 3.3 V, f osc= 5 khz) 6 3 f osc 5 [khz] f osc 5 [khz] 4 MaxDuty [%] T a [ C] MaxDuty T a (V OUT= 3.3 V, f osc= 5 khz) T a [ C] PFMDuty T a (V OUT= 3.3 V, f osc= 5 khz) 5 S-8354 Series T a [ C] MaxDuty [%] MaxDuty T a (V OUT= 3.3 V, f osc= 5 khz) T a [ C] V SH T a (V OUT= 3.3 V, f osc= 5 khz) PFMDuty 15 [%] 1 V SH [V] T a [ C] V SL1 T a (V OUT= 3.3 V, f osc= 5 khz) T a [ C] 1..8 V SL T a (V OUT= 3.3 V, f osc= 5 khz) V SL1 [V] T a [ C] V SL [V] T a [ C] 4 Seiko Instruments Inc.

25 Rev.1. _ 8 T SS vs. Ta (V OUT = 3.3 V, f OSC = 5 khz) 8 T SS vs. Ta (V OUT = 3.3 V, f OSC = 5 khz) 6 6 T SS [ms] 4 T SS [ms] Ta [ C] Ta [ C] 1. V ST1 vs. Ta (V OUT = 3.3 V, f OSC = 5 khz) 1. V ST vs. Ta (V OUT = 3.3 V, f OSC = 5 khz) V ST1 [V].6.4 V ST [V] Ta [ C] Ta [ C] 3.4 V OUT vs. Ta (V OUT = 3.3 V, f OSC = 5 khz) 3.4 V OUT vs. Ta (V OUT = 3.3 V, f OSC = 5 khz) V OUT [V] 3.3 V OUT [V] Ta [ C] Ta [ C] Seiko Instruments Inc. 5

26 Rev.1._ Examples of Major Power Supply Dependence Characteristics (Ta=5 C) 5 I SS1, - V DD (V OUT = 3.3 V, f OSC= 5 khz, T a= 5 C) 1 I SSS - V DD (V OUT = 3.3 V, f OSC= 5 khz, T a= 5 C) 4 8 I SS1, [µa] 3 1 I SSS 6 [µa] 4 f osc [khz] V DD [V] f OSC V DD (f OSC= 5 khz) V DD [V] 3 5 f osc [khz] V DD [V] f OSC V DD (f OSC= 5 khz) V DD [V] 5 I SW - V DD 4 I SW [ma] V DD [V] V OUT - V DD (V OUT= 3.3 V, f OSC= 5 khz, V DD separate type) V IN= 1.98 V, I OUT= 13. ma 3.4 V OUT - V DD (V OUT= 3.3 V, f OSC= 5 khz, V DD separate type) V IN= 1.98 V, I OUT= 13. ma V OUT [V] 3. V OUT [V] V DD [V] V DD [V] 6 Seiko Instruments Inc.

27 Rev.1. _ Output Waveforms 1. S-8353A33 1. I OUT =1 ma, V IN =1.98 V. I OUT =5 ma, V IN =1.98 V Output voltage [.1 V/div] Output voltage [.1 V/div] CONT voltage [1 V/div] CONT voltage [1 V/div] t [1 µs/div] 3. I OUT =1 ma, V IN =1.98 V t [1 µs/div] Output voltage [. V/div] CONT voltage [1 V/div] t [1 µs/div]. S-8354H33 1. I OUT = 1 µ A V IN = 1.98 V. I OUT = 1 ma V IN = 1.98 V Output voltage [.1 V/div] Output voltage [.1 V/div] 4 4 CONT voltage [1 V/div] CONT voltage [1 V/div] t [ µ s/div] t [ µ s/div] 3. I OUT = 5 ma V IN = 1.98 V 4. I OUT = 1 ma V IN = 1.98 V Output voltage [. V/div] Output voltage [. V/div] CONT voltage [1 V/div] 4 CONT voltage [1 V/div] 4 t [ µ s/div] t [ µ s/div] Seiko Instruments Inc. 7

28 Rev.1._ Examples of Transient Response Characteristics (Ta=5 C) (S-8354H33) 1. Power-On (V IN ; V. V) V IN [V] 4 V IN [V] 4 t (1 ms/div). ON/ OFF Pin Response (V ON/OFF ; V. V) ON/OFF (5 khz, I OUT = 1 ma, V IN = V) V OUT [V] t (1 ms/div) ON/OFF (5 khz, I OUT = 5 ma, V IN = V) V OUT [V] V ON/OFF [V] 4 V ON/OFF [V] 4 3. Load Fluctuations t (1 ms/div) V OUT [V] t (1 ms/div) Load Fiuctuation Load Fiuctuation (5 khz, I OUT ; 1 µa 5 ma, V IN = 1.98 V) (5 khz, I OUT ; 5 ma 1 µa, V IN = 1.98 V) V OUT [V] I OUT 5 ma 1 µa I OUT 5 ma 1 µa V OUT [.5 V/div] t ( µs/div) 4. Input Voltage Fluctuations V OUT [.5 V/div] t (5 ms/div) V IN [V] Input voltage fluctuation (5 khz, I OUT = 5 ma) V IN = 1.98 V.64 V V IN [V] Input voltage fluctuation (5 khz, I OUT = 5 ma) V IN =.64 V 1.98 V V OUT [. V/div] V OUT [.4 V/div] t (1 µs/div) t (1 µs/div) 8 Seiko Instruments Inc.

29 Rev.1. _ Reference Data Reference data is provided to determine specific external components. Therefore, the following data shows the characteristics of the recommended external components selected for various applications. 1. Reference Data for External Components Table 16 Efficiency vs. Output Characteristics and Output Voltage vs. Output Current Characteristics for External Components No. Product name Oscillation frequency [khz] Output voltage [V] Control system Inductor Diode Output capacitor 1 S-8353H5MC 5 5. PWM CDRH8D8- MAZ748 F93 (16 V, 47 µf) S-8353H5MC 5 5. PWM CDRH5D8- MAZ748 F93 (6.3 V, µf) 3 S-8353H5MC 5 5. PWM CXLP1- MAZ748 F9 (6.3 V, 47 µf) 4 S-8354A5MC 5 5. PWM/PFM CDRH8D8-11 MAZ748 F93 (6.3 V, µf) 5 S-8354A5MC 5 5. PWM/PFM CXLP1-47 MAZ748 F9 (6.3 V, 47 µf) 6 S-8353A5MC 5 5. PWM CDRH8D8-11 MAZ748 F93 (6.3 V, µf) 7 S-8353A5MC 5 5. PWM CXLP1-47 MAZ748 F9 (6.3 V, 47 µf) 8 S-8353A33MC PWM CDRH8D8-11 MAZ748 F93 (6.3 V, µf) The performance of the external components is shown below. Table 17 Properties of External Components Component Product name Manufacturer Characteristics Inductor CDRH8D8- Sumida Corporation µh, DCR *1 =95 mω, Imax. * =1.6 A, Component height=3. mm CDRH8D µh, DCR *1 =41 mω, Imax. * =.75 A, Component height =3. mm CDRH5D8- µh, DCR *1 =1 mω, Imax. * =.9 A, Component height =3. mm CXLP1- Sumitomo Special Metals µh, DCR *1 =59 mω, Imax. * =.55 A, Co., Ltd. Component height =1. mm CXLP µh, DCR *1 =95 mω, Imax. * =.45 A, Component height =1. mm Diode MAZ748 Matsushita Electric Industrial Co., Ltd, V *3 F =.4 V, I *4 F =.3 A Capacitor F93 (16 V, 47 µf) Nichicon Corporation F93 (6.3 V, µf) F9 (6.3 V, 47 µf) *1. DC resistance *. Maximum allowable current *3. Forward voltage *4. Forward current Caution The values shown in the characteristics column of Table 17 above are based on the materials provided by each manufacturer, however, consider the characteristics of the original materials when using the above products. Seiko Instruments Inc. 9

30 Rev.1._. Reference Data (1) The following shows the actual (a) Output current vs. Efficiency characteristics and (b) Output current vs. Output voltage characteristics under the conditions of No. 1 to 8 in Table 16. (1) S-8353H5MC Efficiency η [%] 1 8 (a) Output current vs. Efficiency Output voltage VOUT [V] (b) Output current vs. Output voltage 5. 6 V IN = V 4.9 V IN = V 4 V IN = 3 V 4.8 V IN = 3 V V IN = 4 V V IN = 4 V () S-8353H5MC Efficiency η [%] 1 8 (a) Output current vs. Efficiency Output voltage VOUT [V] (b) Output current vs. Output voltage 5. 6 VIN = V 4.9 VIN = V 4 V IN = 3 V 4.8 V IN = 3 V V IN = 4 V V IN = 4 V (3) S-8353H5MC Efficiency η [%] 1 8 (a) Output current vs. Efficiency Output voltage VOUT [V] (b) Output current vs. Output voltage 5. 6 V IN = V 4.9 V IN = V 4 V IN = 3 V 4.8 V IN = 3 V V IN = 4 V V IN = 4 V Seiko Instruments Inc.

31 Rev.1. _ (4) S-8354A5MC Efficiency η [%] 1 8 (a) Output current vs. Efficiency Output voltage VOUT [V] (b) Output current vs. Output voltage 5. 6 V IN = V 4.9 V IN = V 4 V IN = 3 V 4.8 V IN = 3 V V IN = 4 V V IN = 4 V (5) S-8354A5MC Efficiency η [%] 1 8 (a) Output current vs. Efficiency Output voltage VOUT [V] (b) Output current vs. Output voltage V IN = V V IN = V 4 V IN = 3 V 4.8 V IN = 3 V V IN = 4 V V IN = 4 V (6) S-8353A5MC Efficiency η [%] 1 8 (a) Output current vs. Efficiency Output voltage VOUT [V] (b) Output current vs. Output voltage V IN = V V IN = V 4 V IN = 3 V 4.8 V IN = 3 V V IN = 4 V V IN = 4 V Seiko Instruments Inc. 31

32 Rev.1._ (7) S-8353A5MC Efficiency η [%] ( a) Output current vs. E fficiency V IN = V V IN = 3 V V IN = 4 V Output current I OUT [ ma] Output voltage V OUT [V] ( b) Output current vs. O utput voltage V IN = V V IN = 3 V V IN = 4 V Output current I OUT [ ma] (8) S-8354A33MC Efficiency η [%] ( a) Output current vs. E fficiency V IN =.9 V V IN = 1.8 V V IN =.7 V Output current I OUT [ ma] Output voltage V OUT [V] ( b) Output current vs. O utput voltage V IN =.9 V V IN = 1.8 V V IN =.7 V Output current I OUT [ ma] 3 Seiko Instruments Inc.

33 Rev.1. _ 3. Reference Data () The following shows the actual output current vs. ripple voltage characteristics under the conditions of No. 1 to 8 in Table 16. (1) S-8353H5MC () S-8353H5MC 1 Output current vs. Ripple voltage 1 Output current vs. Ripple voltage Ripple voltage Vr [mv] V IN = V V IN = 3 V V IN = 4 V Ripple voltage Vr [mv] V IN = V V IN = 3 V V IN = 4 V (3) S-8353H5MC (4) S-8354A5MC Output current vs. Ripple voltage Output current vs. Ripple voltage Ripple voltage Vr [mv] V IN = V V IN = 3 V V IN = 4 V Ripple voltage Vr [mv] V IN = V V IN = 3 V V IN = 4 V (5) S-8354A5MC (6) S-8353A5MC 8 Output current vs. Ripple voltage Output current vs. Ripple voltage Ripple voltage Vr [mv] V IN = V V IN = 3 V V IN = 4 V Ripple voltage Vr [mv] V IN = V V IN = 3 V V IN = 4 V Seiko Instruments Inc. 33

34 Rev.1._ (7) S-8353A5MC (8) S-8353A33MC Ripple voltage Vr [mv] Output current vs. ripple voltage V IN = V V IN = 3 V V IN = 4 V Ripple voltage Vr [mv] Output current vs. ripple voltage V IN =.9 V V IN = 1.8 V V IN =.7 V Seiko Instruments Inc.

35

36

37

38

39

40

41

42

43

44 The information described herein is subject to change without notice. Seiko Instruments Inc. is not responsible for any problems caused by circuits or diagrams described herein whose related industrial properties, patents, or other rights belong to third parties. The application circuit examples explain typical applications of the products, and do not guarantee the success of any specific mass-production design. When the products described herein are regulated products subject to the Wassenaar Arrangement or other agreements, they may not be exported without authorization from the appropriate governmental authority. Use of the information described herein for other purposes and/or reproduction or copying without the express permission of Seiko Instruments Inc. is strictly prohibited. The products described herein cannot be used as part of any device or equipment affecting the human body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus installed in airplanes and other vehicles, without prior written permission of Seiko Instruments Inc. Although Seiko Instruments Inc. exerts the greatest possible effort to ensure high quality and reliability, the failure or malfunction of semiconductor products may occur. The user of these products should therefore give thorough consideration to safety design, including redundancy, fire-prevention measures, and malfunction prevention, to prevent any accidents, fires, or community damage that may ensue.