ADT7221

ADT7221 General Description The ADT7221 is a power supply chip with 5V regulated output. It is composed of one PWM controller and one LDO regulator. It provides the pure and excellent regulated output voltage. 1 A50 2 3 6 5 4 Package outline of the ADT7221 Features • Input voltage range : 7V to 15V • Regulated output voltage : 5V • 350mA output load current available • Externally composed LDO pass transistor • 500kHz fixed frequency internal oscillator • Over voltage protection Applications • DC-DC Converter for 5V output • CCD Camera module • Navigation & Portable Devices • PWM controller with built-in compensation components • Small outline SOT-26 package (2.9mm x 1.6mm body) Typical Application Circuit VIN (12V) C2 VIN DRV Q1 A50 GND OUT C3 OUT PWM FB (ADT7221) L1 U1 C1 * This specifications are subject to be changed without notice Jun. 16. 2008 / Rev. 0.1 1/6 http://www.ad-tech.co.kr ADT7221 Part List Component U1*1 Q1 L1 C1 C2 C3 Description Composite type with a PNP transistor and schottky barrier diode PNP transistor Output filter inductor Output filter capacitor Bypass capacitor Load capacitor for LDO IC Chip transistor Chip inductor Tantalum capacitor Tantalum capacitor Tantalum capacitor Type FP103 MMBT589LT1 47uH/590mA 47uF/10V 10uF/25V 1uF/10V Value *1 : For cost down , it is possible to use discrete component with a PNP transistor and a schottky barrier diode. In this case, you make use the discrete components with proper electrical specification. Table A shows the required key electrical limits. It is recommended to use PNP and schottky barrier diode having equivalent specification in the Table A. Table A : Selection guide for the discrete components Component PNP Collector Current Schottky Barrier Diode Repetitive Peak Reverse Voltage Average Rectified Current -2 30 700 A V mA Parameter Collector to Emitter Voltage Ratings -20 Unit V Remarks Recommend ‘2SB1424’ by ROHM or Equivalent IC Recommend ‘RSX101M-30’ by ROHM or Equivalent Pin Configuration 1 6 A50 2 5 3 4 * This specifications are subject to be changed without notice Jun. 16. 2008 / Rev. 0.1 2/6 http://www.ad-tech.co.kr ADT7221 Pin Description Pin No. 1 2 3 4 5 6 I : Input pin P : Power pin A : Analog pin Name VIN GND PWM FB OUT DRV I/O O I O I/O Type P G D A A A Power supply input Ground Switching output Feedback voltage input LDO output LDO pass transistor drive signal Description O : Output pin G : Ground pin D : Digital pin IO : Input/Output pin Functional Block Diagram VIN Internal REG. BIAS GND REF OSC (500kHz) + + FB ZIN PWM - ERROR AMP ZFB PWM Modulator PreDRIVER LDO DRV OUT * This specifications are subject to be changed without notice Jun. 16. 2008 / Rev. 0.1 3/6 http://www.ad-tech.co.kr ADT7221 Absolute Maximum Ratings Parameter Power supply voltage Power dissipation (Ta=70℃) (Note1) Storage temperature Junction temperature Thermal resistance Symbol VIN PDmax TSTG TJmax ΘJA Min. -65 Typ. 301.2 Max. 23 265 +150 +150 Unit V mW ℃ ℃ ℃/W Note1. derate 301℃/W above +70℃. 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 rating conditions for extended periods may affect device reliability. Operating Ratings Parameter Power supply voltage*2 Operating temperature Junction temperature Max. power dissipation (Ta=70℃)*1 Symbol VIN TOPR TJ PD Min. 7.0 -20 Typ. 12.0 Max. 15.0 +85 +125 180 Unit V ℃ ℃ mW *1 This spec. indicates that junction temperature of the device is under 125℃. In specific applications , this is recommended under this power dissipation specification. *2 Maximum VIN operating range can be extended. In this case, maximum drive current is limited. For using VIN over 15V, refer to the Table B. Table B : Maximum drive current as maximum VIN operating voltage. VIN (V) Drive current (㎃) 16 330 17 310 18 290 19 270 20 250 21 230 22 210 Electrical Characteristics (Ta=25℃, VIN=12V, unless otherwise noted) Parameter Supply current, operating PWM controller Efficiency Oscillator frequency Output voltage LDO Output voltage Output drive current Load regulation Line regulation IO=300mA IO=0 to 350mA VIN=7V to 15V, IO=350mA 4.75 5.0 300 150 20 5.25 350 V mA mV mV IO=300mA IO=300mA (measured at FB pin voltage) 350 5.25 77 500 5.5 625 5.75 % kHz V IO=0mA IO=300mA Condition Min. Typ. 3 10 Max. 15 Unit mA mA Note * This specifications are subject to be changed without notice Jun. 16. 2008 / Rev. 0.1 4/6 http://www.ad-tech.co.kr ADT7221 Typical Performance Characteristics VIN vs. Efficiency (Io=300mA) 90 85 80 75 70 6 8 10 12 VIN (V) 14 16 80 78 76 74 72 0 Io vs. Efficiency (VIN=12V) Efficiency (%) Efficiency (%) 100 200 Io (mA) 300 400 Temp vs. Vout (VIN=12V / Io=300mA) 5.2 5.1 Vout (V) 5.0 4.9 4.8 0 20 40 60 Temp (℃) 80 100 Frequency (KHz) 550 540 530 520 510 500 Temp vs. Frequency (VIN=12V / Io=300mA) 0 20 40 60 Temp (℃) 80 100 * This specifications are subject to be changed without notice Jun. 16. 2008 / Rev. 0.1 5/6 http://www.ad-tech.co.kr ADT7221 Package ; SOT-26, 2.9mm x 1.6mm body (units : mm) * This specifications are subject to be changed without notice Jun. 16. 2008 / Rev. 0.1 6/6 http://www.ad-tech.co.kr