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LT1020

sn1020 1020fcs

Micropower Regulator

and Comparator

■

Input Voltage Range: 4.5V to 36V

■

40µA Supply Current

■

125mA Output Current

■

2.5V Reference Voltage

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Reference Output Sources 1mA and Sinks 0.5mA

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Dual Output Comparator

■

Comparator Sinks 10mA

■

Dropout Detector

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0.2V Dropout Voltage

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Thermal Limiting

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Available in SO Package

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Battery Systems

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Battery Backup Systems

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Portable Terminals

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Portable Instruments

The LT

1020 is a combination micropower positive regu-

lator and free collector comparator on a single monolithic

chip. With only 40µA supply current, the LT1020 can

supply over 125mA of output current. Input voltage range

is from 4.5V to 36V and dropout voltage is 0.6V at 125mA.

Dropout voltage decreases with lower load currents. Also

included on the chip is a class B output 2.5V reference that

can either source or sink current. A dropout detector

provides an output current to indicate when the regulator

is about to drop out of regulation.

The dual output comparator can be used as a comparator

for system or battery monitoring. For example, the com-

parator can be used to warn of low system voltage while

the dropout detector shuts down the system to prevent

abnormal operation. Frequency compensation of the com-

parator for amplifier applications can be obtained by

adding external output capacitance. Dual output or posi-

tive and negative regulators can also be made.

The 2.5V reference will source or sink current. This allows

it to be used as a supply splitter or auxiliary output.

5V Regulator Dropout Voltage and Supply Current

> 5.2V

= 40µA

10µF

0.001µF

OUT

GND

LT1020

1020 TA01

OUTPUT CURRENT (mA)

0.1

0.01

DROPOUT VOLTAGE (V)

0.1

10 1000

1020 TA02

1 100

0.1

SUPPLY CURRENT (mA)

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

, LTC and LT are registered trademarks of Linear Technology Corporation.

Summary of content (16 pages)

PAGE 1
LT1020 Micropower Regulator and Comparator U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO The LT®1020 is a combination micropower positive regulator and free collector comparator on a single monolithic chip. With only 40µA supply current, the LT1020 can supply over 125mA of output current. Input voltage range is from 4.5V to 36V and dropout voltage is 0.6V at 125mA. Dropout voltage decreases with lower load currents. Also included on the chip is a class B output 2.
PAGE 2
LT1020 W W W AXI U U ABSOLUTE RATI GS (Note 1) Input Voltage .......................................................... 36V NPN Collector Voltage ............................................ 36V PNP Collector Voltage ............................. Supply – 36V Output Short Circuit Duration ......................... Indefinite Power Dissipation .............................. Internally Limited Storage Temperature Range ................ – 65°C to 150°C Operating Temperature Range LT1020C ...............
PAGE 3
LT1020 ELECTRICAL CHARACTERISTICS PARAMETER Regulator Feedback Sense Voltage Dropout Detector Current Feedback Bias Current Minimum Load Current Short-Circuit Current Comparator Offset Voltage Bias Current Offset Current Gain-NPN Pull-Down Common Mode Rejection Power Supply Rejection Output Sink Current NPN Saturation Voltage Output Source Current Input Voltage Range Response Time Leakage Current (NPN) TJ = 25°C CONDITIONS MIN TYP MAX UNITS VIN = 12V ∆VOUT = – 0.05V, IOUT = 500µA 2.44 3 2.
PAGE 4
LT1020 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TJ = 25°C. PARAMETER Comparator Offset Current Gain-NPN Pull-Down Common Mode Rejection Power Supply Rejection Output Sink Current Output Source Current Input Voltage Range Leakage Current (NPN) CONDITIONS MIN 0V ≤ VCM ≤ 35V, VIN = 36V ∆VOUT = 29V, RL = 20k 0V ≤ VCM ≤ 35V, VIN = 36V 4.5V ≤ VIN ≤ 36V VIN = 4.
PAGE 5
LT1020 U W TYPICAL PERFOR A CE CHARACTERISTICS Dropout Detector Current Dropout Detector Current 1 0.1 VDIFF = 1V IOUT = 100mA 10 100 REGULATOR OUTPUT CURRENT (mA) IOUT = 25mA 100 IOUT = 5mA 10 IOUT = 1mA 1 0.01 100 1000 70 80 90 100 110 120 130 140 TEMPERATURE (°C) Supply Current Regulator Ripple Rejection Supply Current at Dropout 10 10 IOUT = 100mA 150 1020 G09 1020 G08 70 65 10 1 0.1 0 0.2 0.3 0.4 0.5 0.
PAGE 6
LT1020 U W TYPICAL PERFOR A CE CHARACTERISTICS LT1020 Turn-On Characteristic 5.5 VIN = 15V VOUT = 5V 0 –0.1 OUTPUT CURRENT (mA) VOUT = 5V 5.0 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE CHANGE (%) Regulator Thermal Regulation 0.1 4.5 4.0 NO LOAD 3.5 RL = 50Ω 3.0 RL = 500Ω 2.5 50 2.0 0 0 20 40 60 80 100 120 140 160 180 TIME (ms) 0 0 1 1020 G16 2 5 6 3 4 INPUT VOLTAGE (V) 7 8 1020 G17 U U U PI FU CTIO S Pins 1, 14: No Internal Connection. Pin 9: Ground. Pin 2: Regulator Output.
PAGE 7
LT1020 W BLOCK DIAGRA REF OUT 4 10 – PNP OUT 5 NPN OUT 6 CURRENT LIMIT 3 VIN 2 VOUT 13 DROPOUT DETECTOR + REF 2.5V NONINVERTING 7 INVERTING 8 11 FB 9 GND 1020 BD U W U U APPLICATIO S I FOR ATIO The LT1020 is especially suited for micropower system applications. For example, the comparator section of the LT1020 may be used as a battery checker to provide an indication of low battery. The dropout detector can shut down the system when the battery voltage becomes too low to regulate.
PAGE 8
LT1020 U W U U APPLICATIO S I FOR ATIO than placing large capacitive loads on the reference, no other precautions are necessary and the reference is stable with nominal stray capacitances. REF 4 REF 4 OUTPUT 20Ω 20Ω OR + OUTPUT + 10µF 10µF 1020 F01 Figure 1. Bypassing Reference Overload Protection The main regulator in the LT1020 is current limited at approximately 350mA. The current limit is stable with both input voltage and temperature.
PAGE 9
LT1020 U TYPICAL APPLICATIO S Regulator with Output Voltage Monitor 3 VIN VIN – 500k 5 6 LOGIC VOUT 2 5V 0.001µF LT1020 2.5V + LOGIC OUTPUT 7 REF 8 4 100k + 11 10µF FB GND 9 LOGIC OUTPUT 100k 20k 1M LOGIC OUTPUT GOES LOW WHEN VOUT DROPS BY 100mV VOUT 1020 TA03 5V Regulator Driving Logic with Dropout Detector 3 VIN > 5.2V IQ = 40µA VOUT VIN 2 5V 0.
PAGE 10
LT1020 U TYPICAL APPLICATIO S 1 Amp Low Dropout Regulator VIN VOUT * 2 LT1020 10k* FB CL 3 9 GND 8 –INPUT MJE2955 3 0.001µF 100k + 11 VOUT 5V VIN VOUT 220µF† 0.001µF 1M *FOR CURRENT LIMIT ≈ 1.5A † MUST HAVE LOW ESR. SEVERAL 100µF CAPACITORS CAN BE PARALLELED 150Ω* 100k 0.01µF SEE LT1129 DATA SHEET FOR 700mA OUTPUT VOUT 9 6 10µF + 100k 10µF –5V REG 10mA –VIN Dual Output 150mA Regulator VIN > 5.2V 2 5V 0.
PAGE 11
LT1020 U TYPICAL APPLICATIO S Battery Backup Regulator VOUT 5V BATTERY INPUT 3 VIN 2 2 VOUT + 0.001µF LT1020 GND LT1020 11 9 MAIN POWER INPUT 3 VIN 10µF 1M 11 FB VOUT FB GND 9 50k 1020 TA13 INTERNAL PARASITIC DIODES OF LT1020 1M VOUT VIN 5V Regulator with Shutdown 3 VIN > 5.2V IQ = 40µA VOUT VIN 2 LT1020 10µF 0.001µF GND 5V + NC 1M FB 9 11 500k 100k 2N3904* LOGIC INPUT 1020 TA14 1M *TRANSISTOR USED BECAUSE OF LOW LEAKAGE CHARACTERISTICS.
PAGE 12
LT1020 U TYPICAL APPLICATIO S 1 Amp Regulator with Precision Current Limit VIN 12V 2.2k + 100µF MJE2955 8 – VOUT 5V 1A 3 4 100k + LT1020 0.22µF 100k 220µF† 2 1.2k 7 FB + 5 6 ISC SENSE 0.03Ω 9 11 100k 270Ω 1N4148 RL 1020 TA17 † MUST HAVE LOW ESR. SEVERAL 100µF CAPACITORS CAN BE PARALLELED Logic Output on Dropout VIN 4 8 – 3 LT1020 2 7 VOUT 5V 1M + FB 5 6 9 0.
PAGE 13
LT1020 U TYPICAL APPLICATIO S Charge Pump Voltage Doubler VIN 1M 1N5819 OR EQUIVALENT 51k VOUT + 8 20µF 3 – 5 0.0033µF 6 + 10µF + 7 2N3904 22k 9 VOUT (NL) ≅ 2VIN – 1V VOUT (5mA) ≅ 2VIN – 3V IQ ≅ 300µA 1M 1020 TA20 51k 50mA Battery Charger and Regulator + VIN* + 10µF 10µF 51k 10µF 2N2905 20k + 220k 8 4 – 3 VIN 2 VOUT + LT1020 6 5V 1M 2.5V + FB 0.001µF 6V BATTERY 10µF 11 1M 9 7 *VIN MUST BE GREATER THAN THE BATTERY VOLTAGE PLUS 1.3V 3.
PAGE 14
6 Q5 NPN OUTPUT R1 25Ω Q7 Q6 R36 60k Q8 Q9 Q2 R2 50k Q12 Q10 R37 110.8k 8 –INPUT R6 3k 7 R5 3k Q17 Q18 Q15 Q16 Q14 +INPUT R3 50k Q11 Q13 R35 42k Q21 R7 6.
PAGE 15
LT1020 U PACKAGE DESCRIPTIO J Package 14-Lead CERDIP (Narrow .300 Inch, Hermetic) (Reference LTC DWG # 05-08-1110) .785 (19.939) MAX .005 (0.127) MIN 14 13 11 12 10 9 8 .220 – .310 (5.588 – 7.874) .025 (0.635) RAD TYP 1 2 3 4 5 6 7 .200 (5.080) MAX .300 BSC (7.62 BSC) .015 – .060 (0.381 – 1.524) .008 – .018 (0.203 – 0.457) 0° – 15° .045 – .065 (1.143 – 1.651) .100 (2.54) BSC .014 – .026 (0.360 – 0.660) NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE OR TIN PLATE LEADS .125 (3.
PAGE 16
LT1020 U PACKAGE DESCRIPTIO SW Package 16-Lead Plastic Small Outline (Wide .300 Inch) (Reference LTC DWG # 05-08-1620) .050 BSC .045 ±.005 .030 ±.005 TYP .398 – .413 (10.109 – 10.490) NOTE 4 16 N 15 14 13 12 11 10 9 N .325 ±.005 .420 MIN .394 – .419 (10.007 – 10.643) NOTE 3 1 2 3 N/2 N/2 RECOMMENDED SOLDER PAD LAYOUT 1 .005 (0.127) RAD MIN .009 – .013 (0.229 – 0.330) .291 – .299 (7.391 – 7.595) NOTE 4 .010 – .029 × 45° (0.254 – 0.737) 2 3 4 5 6 .093 – .104 (2.362 – 2.