AIC1741 LOW DROPOUT ADJUSTABLE REGULATOR SPEC NO: DS-1741-00 FEATURES 1% Accuracy 1.235V Voltage Reference. Fast Transient Response. Low Ground Current at 55µA. Wide Output Current Range, 10µA~80mA. Output Programmable from 1.235V~11V. Low Temperature Coefficiency. Error Flag Warns of Output Dropout. DESCRIPTION The AIC1741 is a low power precision adjustable regulator with 80mA output capability. The device can be used as a secondary regular to provide feedback in a switching power supply. The AIC1741 circuitry includes an internal wide band amplifier, a precision bandgap reference, and a PMOS output transistor. The feedback input can be connected to an external resistor APPLICATIONS divider to program the sensed output voltage. Voltage Regulator for Pentium® CPUs. Wireless Communication System. 5V to 3.3V Regulator for VGA Cards. Battery Powered Systems. The VOUT pin provides loop frequency compensation when used as a part of a larger servo system. Although the device works as a stand-alone regulator, it can also drive an NPN power transistor to construct a high current low dropout regulator, with only very minor current loss to ground. TYPICAL APPLICATION CIRCUIT VIN 5V 1 VOUT Q1 TIP31C C3 10µF + R3 2K R1 390 + 3 GND C2 33µF 4 8 FB 7 2 NC VOUT 3.3V/3 A VIN + C1 10µF FLAG 6 NC 5 NC AIC1741 R2 1.2K 5V to 3.3V Regulator for VGA Cards. ORDERING INFORMATION AIC1741 XX ORDER NUMBER PACKAGE TYPE N: PLASTIC DIP S: SMALL OUTLINE TEMPERATURE RANGE C: 0°C~+70°C AIC1741CN (PLASTIC DIP) AIC1741CS (PLASTIC SO) Pentium ® PIN CONFIGURATION TOP VIEW VOUT 1 8 VIN NC 2 7 FB GND 3 6 FLAG NC 4 5 NC is a registered trademark of Intel Corporation ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 1 AIC1741 LOW DROPOUT ADJUSTABLE REGULATOR SPEC NO: DS-1741-00 ABSOLUTE MAXIMUM RATINGS Input Supply Voltage ................……………...................................................... -0.3~12V Feedback Input Voltage .............……………...................................................... -0.3~12V Shutdown Input Voltage ...........……………....................................................... -0.3~12V Error Comparator Output ..........………….......................................................... -0.3~12V Operating Junction Temperature Range ...............…………......................................... -65°C~150°C Storage Temperature Range ……….......................................... -40°C~125°C TEST CIRCUIT 8 VIN + CIN 1µF 1mA 7 VOUT VIN NC FB 6 FLAG 5 1 VOUT 3.3V 2 COUT 10µF GND 3 NC NC 4 R1 2K R2 1.2K AIC1741 ELECTRICAL CHARACTERISTICS (Ta=25°°C, CIN=1µ µF, COUT=10µµF, unless otherwise specified. Test conditions are referred to TEST CIRCUIT.) PARAMETER TEST CONDITIONS MIN. TYP. MAX. UNIT 3.267 3.3 3.333 V 50 150 PPM/°C Output Voltage VIN=3.6~12V, No Load, VOUT=3.3V Output Voltage Temperature Coefficiency (Note 1) Line Regulation VIN=3.6~12V, IL=1mA, VOUT=3.3V 3 10 mV Load Regulation VIN=7V, IL=0.1~80mA, VOUT=3.3V 4 10 mV 0.2 200 10 300 mV (Note 3) IL=0.1mA IL=80mA, VOUT=3.3V Ground Current VIN=4~12V, IO=0.1mA~IMAX 55 80 µA Flag Pin Off Leakage Current VIN=7V 1 µA Flag Pin Pull Low Voltage IOL=1mA, VIN=2.9V 300 mV (Note 2) Dropout Voltage 100 Flag Pin Upper Threshold 40 60 mV Voltage Flag Pin Lower Threshold 68 88 mV Voltage Note 1: Guaranteed by design. Note 2: Regulation is measured at constant junction temperature, using pulse testing with a low ON time. Note 3: Dropout voltage is defined as the input to output differential at which the output voltage drops 100mV below the value measured with a 1V differential. ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 2 AIC1741 LOW DROPOUT ADJUSTABLE REGULATOR SPEC NO: DS-1741-00 TYPICAL PERFORMANCE CHARACTERISTICS Reference Voltage vs. Temperature Ground Current vs. Input Voltage 1.28 60 50 Ground Current (µA) Reference Voltage (V) 1.26 VREF=1.244V 1.24 VREF=1.225V 1.22 VREF=1.225V 1.2 40 30 20 10 1.18 -50 -25 0 25 50 75 100 0 125 0 2 4 6 10 12 Dropout Voltage vs. Load Current Ground Current vs. Temperature 60 200 VOUT=3.3V Dropout Voltage (mV) 58 Ground Current (µA) 8 Input Voltage (V) Temperature (°C) IL=80mA 56 54 IL=0.1mA 150 100 50 52 0 50 -50 -25 0 25 50 75 100 0 125 20 40 Temperature(°C) Dropout Voltage vs Temperature 100 Bias Current vs. Temperature 40 VOUT=3.3V IL=80mA Bias Current (nA) 250 Dropout Voltage(mV) 80 Load Current (mA) 300 200 150 100 50 0 60 30 20 IL=0.1mA -50 -25 0 25 50 75 100 125 10 -50 -25 0 Temperature(°C) 25 50 75 100 125 Temperature (°C) ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 3 AIC1741 LOW DROPOUT ADJUSTABLE REGULATOR SPEC NO: DS-1741-00 TYPICAL PERFORMANCE CHARACTERISTICS (CONTINUED) Minimum Operating Voltage vs Temperature Minimum Operating Voltage (V) 2.8 2.7 2.6 2.5 2.4 2.3 2.2 -50 -25 0 25 50 Temperature (°C) 75 100 125 BLOCK DIAGRAM 8 VIN 7 + FB 1 VOUT 66mV + 6 FLAG 1.235V, Reference 3 GND PIN DESCRIPTIONS PIN 1: VOUT - Output pin. PIN 2: NC - PIN 3: GND - Power GND. PIN 4: NC - PIN 5: NC - PIN 6: FLAG - Open drain output of error flag warns. PIN 7: FB - Error amplifier positive feedback (see Block Diagram) PIN 8: VIN - Power supply input. ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 4 AIC1741 LOW DROPOUT ADJUSTABLE REGULATOR SPEC NO: DS-1741-00 APPLICATION INFORMATIONS The AIC1741 has two major applications, one as a low dropout linear regulator and another an error amplifier for a switching power supply to provide precision feedback control. Use as a Linear Regulator nearby noise sources can also upset the output. This may especially be a problem when using high value external resistors to set the output voltage. Adding a 100pF capacitor between output and feedback and increasing the output capacitor to at least 3.3µF will cure this problem. When AIC1741 is connected as a low dropout linear regulator, two external divider resistors are needed to The AIC1741 can drive low cost NPN bipolar set the output voltage (see Test Circuit). The output transistor to deliver more output current. Typical voltage can be calculated from the following formula: application circuit is an example of 5V to 3.3V linear VOUT=VREF(1+R1/R2)+IFBR1 regulator for VGA cards power supply. A 390Ω resistor and 1µF capacitor are needed between where VREF is the nominal 1.235V reference voltage VOUT pin and ground for stability. The minimum and IFB is the feedback pin bias current, nominally dropout voltage between input to output is VBEQ1+VDS -20nA. For better accuracy, the recommended of AIC1741 output PMOSFET, typical 1V @ 3A maximum value of R2 is 100KΩ. output current. A 1µF (or greater) capacitor is required between the AIC1741 output and ground for stability. Without this Use as an Error Amplifier capacitor the part will oscillate. Even though most Fig. 1 shows a popular application for the AIC1741 in types of capacitor may work, if Aluminum electrolytic switching power supply. The output voltage is sensed type is used, the equivalent series resistance (ESR) between FB pin and GND pin of the AIC1741 through should be held to 5Ω. or less. Many Aluminum the divider resistor. The VIN pin servos to control the electrolytics have electrolytes that freeze at about duty cycle of the pulse width modulator to stabilize -30°C, so solid tantalums are recommended for the output voltage at the set voltage. The FB pin and operation below -25°C. The value of this capacitor VIN pin are in same phase while the FB pin and may be increased without limit. VOUT pin are in opposite phases. Connecting a capacitor from VOUT pin to FB pin provides The output capacitance required for stability varies frequency compensation for the control loop. The with output voltage (smaller for higher output voltage) AIC1741 provides output voltage remote sensing to and output current (smaller for lower output currents). improve precision and regulation specifications of the At the worst-case situation of a 80mA load at 1.235V output of the switching power supply. output (output shorted to FB pin) a 3.3 µF or greater capacitor should be used. A 0.1µF capacitor should be placed from the AIC1741 input to ground if the lead inductance between the input and power source exceeds 500nH (approximately 10 inches of trace). Noise injection into the feedback terminal of the AIC1741 from ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 5 AIC1741 LOW DROPOUT ADJUSTABLE REGULATOR SPEC NO: DS-1741-00 APPLICATION EXAMPLES C3 SC + AIC1562 TC VCC GND FB C1 47µF Q2 C4 VOUT : 2.5V~3.5V/10A L1 + D1 C4 ZD1 C2 220pF 5.1V R8 10K VIN 5V 1000µF/6.3Vx2 C6 7.5µF 0.022µF R2 24K + 1000µF 12V R1 1K SE BST MTD20N03DH Q1 2N2907A D3 BYV118 D2 1N4148 VIN 1N4148 0.1µF C10 C11 0.1µF 0.1µF 1000µF/6.3V x2 x2 x5 + C13 P5 MICROPROCESSOR CPU FB R2* GND VOUT C11, C12: Ceramic Capacitor L1: Iron Powder Core VOUT= (1+R10/1K)x1.235V AIC1741 Fig. 1 R10 R7 C5 470 0.1µF 1K R3 1K CPU Power Supply for P5 Mother Board PHYSICAL DIMENSIONS 8 LEAD PLASTIC DIP 8 LEAD PLASTIC SO 4.80±0.20 9.3±0.3 6.0±0.2 3.8±0.2 6.2±0.2 8.0±0.5 0.6±0.3 2.5±0.1 10°max 8.5±1.0 0.5±0.1 2.54±0.10 0.45±0.10 0.2 ± 0.1 3.2±0.3 1.5±0.2 0.25±0.10 1.27±0.10 3.3±0.1 0.015X45° 8° max. UNIT: mm ANALOG INTEGRATIONS CORPORATION www.analog.com.tw 4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C. TEL: (8863)577-2500 FAX:(8863)577-2510 6