MICROPOWER SC70-5 & SOT23-5 LOW DROPOUT REGULATORS

Transcription

1 MICROPOWER SC7- & SOT3- LOW DROPOUT REGULATORS ZXCL3V, ZXCL3V6, ZXCL3V8, ZXCL3V3, ZXCL3V33, ZXCL3V4 ZXCL, ZXCL6, ZXCL8, ZXCL3, ZXCL33, ZXCL4 DESCRIPTION The ZXCL series have been designed with space sensitive systems in mind. They are available in the ultra small SC7- package, which is half the size of other SOT3 based regulators. The devices can be used with all types of output capacitors including low ESR ceramics and typical dropout voltage, is only at ma load. Supply current is minimised with a ground pin current of only A at full ma load. Logic control allows the devices to be shut down, consuming typically less than na. These features make the device ideal for battery powered applications where power economy is critical. FEATURES -pin SC7 package for the ultimate in space saving -pin SOT3 industry standard pinout Can be used with all types of output capacitor Low dropout at ma load A ground pin current with full ma load Typically less than na ground pin current on shutdown.,.6,.8, 3, 3.3 and 4 volts output Very low noise, without bypass capacitor Thermal overload and over-current protection -4 to + C operating temperature range No-load stable For applications requiring improved performance over alternative devices, the ZXCL is also offered in the pin SOT3 package with an industry standard pinout. The devices feature thermal overload and over-current protection and are available with output voltages of.v,.6v,.8v, 3V, 3.3V and 4V. Other voltage options between.v and 4V can be provided. Contact Zetex marketing for further information. The ZXCL series are manufactured using CMOS processing, however advanced design techniques mean that output noise is improved even when compared to other bipolar devices. APPLICATIONS Cellular and Cordless phones Palmtop and laptop computers PDA Hand held instruments Camera, Camcorder, Personal Stereo PCMCIA cards Portable and Battery-powered equipment No-Load Stability, the ZXCL device will maintain regulation and is stable with no external load. e.g. CMOS RAM applacations. TYPICAL APPLICATION CIRCUIT PACKAGE FOOTPRINT

2 ABSOLUTE MAXIMUM RATINGS Terminal Voltage with respect to GND -.3V to 7.V E N -.3V to V V O -.3V to.v Package Power Dissipation (T A= C) Output short circuit duration Continuous Power Dissipation Operating Temperature Range Storage Temperature Range Infinite Internally limited -4 C to + C - C to + C SC7-3mW (Note ) SOT3-4mW (Note ) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS = V O +.V, all values at T A = C (Unless otherwise stated) LIMITS SYMBOL PARAMETER CONDITIONS UNITS MIN TYP MAX Input Voltage (note). V V O Output Voltage I O = ma ZXCL / 3V ZXCL6 / 3V6 ZXCL8 / 3V8 ZXCL3 / 3V3 ZXCL33 / 3V33 ZXCL4 / 3V4 I O = ma V O +.V< < max. ZXCL / 3V ZXCL6 / 3V6 ZXCL8 / 3V8 ZXCL3 / 3V3 ZXCL33 / 3V33 ZXCL4 / 3V4 V O / T Output Voltage Temperature Coefficient I O(MAX) Output Current ZXCL / 3V only I OLIM Over Current Limit ZXCL / 3V only I Q Ground pin current No Load I O = ma, I O = ma, V V - ppm/ C ma ma A A A

3 ELECTRICAL CHARACTERISTICS = V O +.V, all values at T A = C (Unless otherwise stated) SYMBOL PARAMETER CONDITIONS LIMITS UNITS MIN TYP MAX V DO Dropout Voltage Note 3 ZXCL / 3v I O =ma I O =ma ZXCL6 / 3v6 I O =ma I O =ma ZXCL8 / 3v8 I O =ma I O =ma ZXCL3 / 3v3 I O =ma I O =ma ZXCL33 / 3v33 I O =ma I O =ma ZXCL4 / 3v4 I O =ma I O =ma 8 V LNR Line Regulation =(V O +.V) to.v, I O =ma.. %/V V LDR Load Regulation I O =ma to ma..4 %/ma E N Output Noise Voltage f=hz to khz, C O =µf, µv rms V ENH Enable pin voltage for V normal operation T A = -4 C. V ENL Enable pin voltage for.8 V output shutdown V ENHS Enable pin hysteresis I EN Enable Pin input V EN =.V na current I QSD Shutdown supply current V EN =V µa T SD Thermal Shutdown Temperature 6 C Device testing is performed at T A= C. Device thermal performance is guaranteed by design. Note: Maximum power dissipation is calculated assuming the device is mounted on a PCB measuring inches square Note : Output Voltage will start to rise when exceeds a value or approximately.3v. For normal operation, (min) > V OUT (nom) +.V. Note 3: Dropout voltage is defined as the difference between and V O, when V O has dropped below its nominal value. Nominal value of V O is defined at =V O+.V

4 TYPICAL CHARACTERISTICS (ZXCL8 / 3 shown) 6. Voltage (V) 4 3 I OUT = ma I OUT =ma Input Voltage (V) Input to Output Characteristics Dropout Voltage (V) Output Current (ma) Dropout Voltage v Output Current Output Voltage (V).8.8 =3.3V No Load Temperature ( C) Output Voltage v Temperature Ground Current (µa) =3.3V No Load Temperature ( C) Ground Current v Temperature Ground Current (µa) 3 No Load Ground Current (µa) =V =3.3V 3 4 Input Voltage (V) Ground Current v Input Voltage 7 Load Current (ma) Ground Current v Load Current 4

5 TYPICAL CHARACTERISTICS Voltage (V) =µf Enable =V =ma = ma Time (µs) Start-Up Response =3.3V =ma = ma V OUT () (ma) C OUT =µf =µf C - OUT =µf =µf Time (ms) Load Response =V = ma to ma V OUT () (V) =µf T r &T f =.µs Time (ms) Line Rejection =ma V OUT () (V) =µf T r &T f =.µs Time (ms) Line Rejection = ma Power Supply Rejection (db) =µf =.µf =µf All Caps Ceramic Surface Mount = ma k k k M Frequency (Hz) Power Supply Rejection v Frequency Noise µv/ Hz. No Load, =µf No Load, =µf = ma, =µf = ma, =µf. k k k M Frequency (Hz) Output Noise v Frequency

6 PIN DESCRIPTION Pin Name G ND E N N/C V O Pin Function Supply Voltage Ground Active HIGH Enable input. TTL/CMOS logic compatible. Connect to or logic high for normal operation No Connection Regulator Output CONNECTION DIAGRAMS SOT3- Package Suffix E SC7- Package Suffix H SC7- Package Suffix H V O V O E N G ND E N 3 4 N/C G ND E N 3 4 N/C N/C G ND 3 4 V O Top View Top View Top View ZXCLxxx ZXCLxxx ZXCL3Vxx SCHEMATIC DIAGRAM 6

7 Input to Output Diode In common with many other LDO regulators, the ZXCL device has an inherent diode associated with the output series pass transistor. This diode has its anode connected to the output and its cathode to the input. The internal diode is normally reverse biased, but will conduct if the output is forced above the input by more than a V BE (approximately.6v). Current will then flow from Vout to Vin. For safe operation, the maximum current in this diode should be limited to ma continuous and 3mA peak. An external schottky diode may be used to provide protection when this condition cannot be satisfied. Increased Output current Any ZXCL series device may be used in conjunction with an external PNP transistor to boost the output current capability. In the application circuit shown below, a FMMT77 device is employed as the external pass element. This SOT3 device can supply up to.a maximum current subject to the thermal dissipation limits of the package (6mW). Alternative devices may be used to supply higher levels of current. Note that with this arrangement, the dropout voltage will be increased by the V BE drop of the external device. Also, care should be taken to protect the pass transistor in the event of excessive output current. Scheme to boost output current to A 7

8 APPLICATIONS INFORMATION Enable Control A TTL compatible input is provided to allow the regulator to be shut down. A low voltage on the Enable pin puts the device into shutdown mode. In this mode the regulator circuit is switched off and the quiescent current reduces to virtually zero (typically less than na) for input voltages above the minimum operating threshold of the device. A high voltage on the Enable pin ensures normal operation. The Enable pin can be connected to or driven from an independent source of up to V maximum. (e.g. CMOS logic) for normal operation. There is no clamp diode from the Enable pin to, so the pin may be at any voltage within its operating range irrespective of the voltage on the Enable pin. However input voltage rise time should be kept below ms to ensure consistent start-up response. C R Figure Circuit Connection Current Limit The ZXCL devices include a current limit circuit which restricts the maximum output current flow to typically 3mA. Practically the range of over-current should be considered as minimum 6mA to maximum 8mA. The device s robust design means that an output short circuit to any voltage between ground and V OUT can be tolerated for an indefinite period. Thermal Overload Thermal overload protection is included on chip. When the device junction temperature exceeds a minimum C the device will shut down. The sense circuit will re-activate the output as the device cools. It will then cycle until the overload is removed. The thermal overload protection will be activated when high load currents or high input to output voltage differentials cause excess dissipation in the device. Start up delay A small amount of hysteresis is provided on the Enable pin to ensure clean switching. This feature can be used to introduce a start up delay if required. Addition of a simple RC network on the Enable pin provides this function. The following diagram illustrates this circuit connection. The equation provided enables calculation of the delay period. T d Figure Start up delay (T d) T d(nom) VIN = RCIn V. IN Calculation of start up delay as above 8

9 APPLICATIONS INFORMATION (Cont) Power Dissipation The maximum allowable power dissipation of the device for normal operation (Pmax), is a function of the package junction to ambient thermal resistance (θja), maximum junction temperature (Tjmax), and ambient temperature (Tamb), according to the expression: P max = (Tj max T amb) / θ ja The maximum output current (I max) at a given value of Input voltage () and output voltage (V OUT) is then given by I max =P max / ( -V OUT ) The value of θja is strongly dependent upon the type of PC board used. Using the SC7 package it will range from approximately 8 C/W for a multi-layer board to around 4 C/W for a single sided board. It will range from 8 C/W to 3 C/W for the SOT3- package. To avoid entering the thermal shutdown state, Tj max should be assumed to be C and I max less than the over-current limit,(i OLIM). Power derating for the SC7 and SOT3- packages is shown in the following graph. Max Power Dissipation (mw) 4 3 SC Temperature ( C) Derating Curve SOT3 Capacitor Selection and Regulator Stability The device is designed to operate with all types of output capacitor, including tantalum and low ESR ceramic. For stability over the full operating range from no load to maximum load, an output capacitor with a minimum value of F is recommended, although this can be increased without limit to improve load transient performance. Higher values of output capacitor will also reduce output noise. Capacitors with ESR less than. are recommended for best results. The dielectric of the ceramic capacitance is an important consideration for the operation over temperature. Zetex recommends minimum dielectric specification of X7R for the input and output capacitors. For example a ceramic capacitor with X7R dielectric will lose % of its capacitance over a -4 Cto C temperature range, whereas a capacitor with a YV dielectric loses 8% of its capacitance at -4 C and 7% at C. An input capacitor of F (ceramic or tantalum) is recommended to filter supply noise at the device input and will improve ripple rejection. The input and output capacitors should be positioned close to the device, and a ground plane board layout should be used to minimise the effects of parasitic track resistance. Dropout Voltage The output pass transistor is a large PMOS device, which acts like a resistor when the regulator enters the dropout region. The dropout voltage is therefore proportional to output current as shown in the typical characteristics. Ground Current The use of a PMOS device ensures a low value of ground current under all conditions including dropout, start-up and maximum load. Power Supply Rejection and Load Transient Response Line and Load transient response graphs are shown in the typical characteristics. These show both the DC and dynamic shift in the output voltage with step changes of input voltage and load current, and how this is affected by the output capacitor. If improved transient response is required, then an output capacitor with lower ESR value should be used. Larger capacitors will reduce over/undershoot, but will increase the settling time. Best results are obtained using a ground plane layout to minimise board parasitics. 9

10 S7- PACKAGE OUTLINE SC7- PACKAGE DIMENSIONS MILLIMETRES INCHES DIM MIN MAX MIN MAX A..393 A..39 A b C D. BSC.787 BSC E. BSC.86 BSC E. BSC.49 BSC e.6 BSC. BSC e.3 BSC. BSC L a 8 8 CONTROLLING DIMENSIONS IN MILLIMETRES APPROX CONVERTED DIMENSIONS IN INCHES SOT3- PACKAGE INFORMATION SOT3- PACKAGE DIMENSIONS MILLIMETRES INCHES DIM MIN MAX MIN MAX A A....9 A b C D E E e.9 REF.374 REF e.9 REF.748 REF L a 3 3 CONTROLLING DIMENSIONS IN MILLIMETRES APPROX CONVERTED DIMENSIONS IN INCHES

11 ORDERING INFORMATION Device Output Voltage V Package Partmarking ZXCLH. SC7 LA ZXCL6H.6 SC7 L6A ZXCL8H.8 SC7 L8A ZXCL3H 3. SC7 L3A ZXCL33H 3.3 SC7 L33A ZXCL4H 4. SC7 L4A ZXCL3VH. SC7 LC ZXCL3V6H.6 SC7 L6C ZXCL3V8H.8 SC7 L8C ZXCL3V3H 3. SC7 L3C ZXCL3V33H 3.3 SC7 L33C ZXCL3V4H 4. SC7 L4C ZXCLE. SOT3- LB ZXCL6E.6 SOT3- L6B ZXCL8E.8 SOT3- L8B ZXCL3E 3. SOT3- L3B ZXCL33E 3.3 SOT3- L33B ZXCL4E 4. SOT3- L4B Zetex plc Europe Americas Asia Pacific Zetex plc Fields New Road Chadderton Oldham, OL9 8NP United Kingdom Telephone (44) Fax: (44) uk.sales@zetex.com Zetex GmbH Streitfeldstraße 9 D-8673 München Germany Telefon: (49) Fax: (49) europe.sales@zetex.com Zetex Inc 7 Veterans Memorial Hwy Hauppauge, NY788 USA Telephone: (63) 36 Fax: (63) 36 8 usa.sales@zetex.com Zetex (Asia) Ltd 37-4 Metroplaza, Tower Hing Fong Road Kwai Fong Hong Kong Telephone: () 6 6 Fax: () asia.sales@zetex.com These offices are supported by agents and distributors in major countries world-wide. This publication is issued to provide outline information only which (unless agreed by the Company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services concerned. The Company reserves the right to alter without notice the specification, design, price or conditions of supply of any product or service. For the latest product information, log on to