NSC LP2956IN, LP2956IMX, LP2956IM, LP2956AIMX, LP2956AIM Datasheet

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LP2956/LP2956A Dual Micropower Low-Dropout Voltage Regulators

General Description

The LP2956 is a micropower voltage regulator with very low quiescent current (170 µAtypical at light loads) and very low dropout voltage (typically 60 mV at 1 mA load current and 470 mV at 250 mA load current on the main output).

The LP2956 retains all the desirable characteristics of the LP2951, but offers increased output current (main output), an auxiliary LDO adjustable regulated output (75 mA), and additional features.

The auxiliary output is always on (regardless of main output status), so it can be used to power memory circuits.

Quiescent current increases only slightly at dropout, which prolongs battery life.

The error flag goes low if the main output voltage drops out of regulation.

An open-collector auxiliary comparator is included, whose inverting input is tied to the 1.23V reference.

Reverse battery protection is provided. The parts are available in DIP and surface mount packages.

Features

n Output voltage adjusts from 1.23V to 29V n Guaranteed 250 mA current (main output) n Auxiliary LDO (75 mA) adjustable output n Auxiliary comparator with open-collector output n Shutdown pin for main output n Extremely low quiescent current n Low dropout voltage n Extremely tight line and load regulation n Very low temperature coefficient n Current and thermal limiting n Reverse battery protection

Applications

n High-efficiency linear regulator n Low dropout battery-powered regulator n µP system regulator with switchable high-current V

Block Diagram

LP2956

DS011339-1

May 1999

LP2956/LP2956A Dual Micropower Low-Dropout Voltage Regulators

Connection Diagrams

16–Pin DIP

DS011339-2

Order Number LP2956IN or LP2956AIN

See NS Package Number N16A

Order Number LP2956AMJ-QML or 5962-9554701QEA

See NS Package Number J16A

16-Pin Surface Mount

DS011339-3

Order Number LP2956IM or LP2956AIM

See NS Package Number M16A

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Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

Storage Temperature Range −65˚C to +150˚C Operating Junction

Temperature Range −40˚C to +125˚C

Lead Temperature

(Soldering, 5 seconds) 260˚C

Power Dissipation (Note 2) Internally Limited

Input Supply Voltage −20V to +30V Feedback Input Voltage (Note 3) −0.3V to +5V Aux. Feedback Input Voltage (Note 3) −0.3V to +5V Shutdown Input Voltage (Note 3) −0.3V to +30V Comparator Input Voltage (Notes 3,

4) −0.3V to +30V Comparator Output Voltage (Notes 3,

4) −0.3V to +30V ESD Rating (Note 16) 2 kV

Electrical Characteristics

Limits in standard typeface are for T

25˚C, and limits in boldface type apply over the full operating temperature range. Limits are guaranteed by production testing or correlation techniques using standard Statistical Quality Control (SQC) methods. Unless otherwise specified: V

6V, C

2.2 µF (Main Output) and 10 µF (Auxiliary Output), Feedback pin is tied to 5V Tap

pin, C

1 µF, V

0V, Main Output pin is tied to Output Sense pin, Auxiliary Output is programmed for 5V. The main

regulator output hasa1mAload, the auxiliary regulator output has a 100 µA load.

Symbol Parameter Conditions Typical LP2956AI LP2956I Units

Min Max Min Max

MAIN OUTPUT

Output Voltage 5.0 4.975 5.025 4.950 5.050

4.940 5.060 4.900 5.100 V

1mA≤I

≤250 mA 5.0 4.930 5.070 4.880 5.120

Temperature Coefficient (Note 5) 20 100 150 ppm/˚C

Line Regulation V

6V to 30V 0.03 0.1 0.2

0.2 0.4

Load Regulation I

1 mA to 250 mA 0.04 0.16 0.20

0.1 mA to 1 mA (Note 6) 0.20 0.30

IN–VO

Dropout Voltage I

1 mA 60 100 100

(Note 7) 150 150

50 mA 240 300 300

420 420 mV

100 mA 310 400 400

520 520

250 mA 470 600 600

800 800

LIMIT

Current Limit R

1Ω 380 500 500 mA

530 530

Thermal Regulation (Note 8) 0.05 0.2 0.2

Output Noise Voltage C

2.2 µF 400

(10 Hz to 100 KHz) C

33 µF 260 µV RMS

100 mA C

33 µF (Note 9) 80

Feedback Pin Voltage 1.23 1.215 1.245 1.205 1.255 V

Feedback Pin Bias 20 40 40 nA Current 60 60

Output Leakage I

(SD IN)

≥ 1 µA 3 10 10 µA

(OFF) In Shutdown V

30V, V

OUT

0V 20 20

AUXILIARY OUTPUT

Feedback Pin Voltage 1.23 1.22 1.25 1.21 1.26 V

1.21 1.26 1.20 1.27

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Electrical Characteristics (Continued)

Limits in standard typeface are for T

6V, C

2.2 µF (Main Output) and 10 µF (Auxiliary Output), Feedback pin is tied to 5V Tap

pin, C

1 µF, V

0V, Main Output pin is tied to Output Sense pin, Auxiliary Output is programmed for 5V. The main

regulator output hasa1mAload, the auxiliary regulator output has a 100 µA load.

Symbol Parameter Conditions Typical LP2956AI LP2956I Units

Min Max Min Max

AUXILIARY OUTPUT

Feedback Voltage Temperature Coefficient

20 ppm/˚C

Feedback Pin Bias 10 20 20 nA Current 30 30 Line Regulation 6V ≤ VIN≤ 30V 0.07 0.3 0.4

0.5 0.6

Load Regulation I

0.1 mA to 1 mA 0.1 0.3 0.4

1 mA to 75 mA (Note 10) 0.6 1.0

IN–VO

Dropout Voltage I

1 mA 100 200 200 mV

300 300

50 mA 400 600 600 mV

700 700

75 mA 500 700 700 mV

850 850

Output Noise C

10 µF 300

(10 Hz–100 KHz) C

33 µF (Note 9) 100 µV RMS

10 mA

LIM

Current Limit V

OUT

0V (Note 13) 80 200 200 mA

250 250

Thermal Regulation (Note 8) 0.2 0.5 0.5

DROPOUT DETECTION COMPARATOR

Output “HIGH” Leakage V

30V 0.01 1 1 µA

Output “LOW” Voltage V

4V 150 250 250 mV

(COMP)=400 µA 400 400

THR

Upper Threshold Voltage (Note 11) −240 −320 −150 −320 −150 mV (max) −380 −100 −380 −100 V

THR

Lower Threshold Voltage (Note 11) −350 −450 −230 −450 −230 mV (min) −640 −160 −640 −160 HYST Hysteresis (Note 11) 110 mV

SHUTDOWN INPUT

Input Current to Disable

Output

(Note 12) 0.03 0.5 0.5 µA

Shutdown Input High I

(SD IN)

≥ 1 µA 900 900 mV

Threshold 1200 1200 V

Shutdown Input Low VO≥ 4.5V 400 400 mV

Threshold 200 200

AUXILIARY COMPARATOR

(high) Upper Trip Point (Note 14) 1.236 1.20 1.28 1.20 1.28 V

1.19 1.29 1.19 1.29

(low) Lower Trip Point (Note 14) 1.230 1.19 1.27 1.19 1.27 V

1.18 1.28 1.18 1.28

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Electrical Characteristics (Continued)

Limits in standard typeface are for T

6V, C

2.2 µF (Main Output) and 10 µF (Auxiliary Output), Feedback pin is tied to 5V Tap

pin, C

1 µF, V

0V, Main Output pin is tied to Output Sense pin, Auxiliary Output is programmed for 5V. The main

regulator output hasa1mAload, the auxiliary regulator output has a 100 µA load.

Symbol Parameter Conditions Typical LP2956AI LP2956I Units

Min Max Min Max

AUXILIARY COMPARATOR

HYST Hysteresis 6 mV I

Output “HIGH” Leakage V

30V 0.01 1 1 µA

(COMP)=1.3V 22

Output “LOW” Voltage VIN(COMP)=1.1V 150 250 250 mV

(COMP)=400 µA 400 400

Input Bias Current 0 ≤ VIN(COMP) ≤ 5V 10 −30 30 −30 30 nA

−50 50 −50 50

GROUND PIN CURRENT

GND

Ground Pin Current IL(Main Out)=1 mA 170 250 250 µA (Note 15) I

(Aux. Out)=0.1 mA 280 280

(Main Out)=50 mA 1.1 2 2

(Aux. Out)=1mA 2.5 2.5

(Main Out)=100 mA 3 6 6

(Aux. Out)=1mA 88

(Main Out)=250 mA 16 28 28 mA

(Aux. Out)=1mA 33 33

(Main Out)=1mA 3 6 6

(Aux. Out)=50 mA 88

(Main Out)=1mA 6 8 8

(Aux. Out)=75 mA 10 10

GND

Ground Pin Current V

4.5V 325 325

at Dropout (Note 15) I

(Main Out)=0.1 mA 270 350 350

(Aux. Out)=0.1 mA µA

GND

Ground Pin Current No Load on Either Output 120 180 180 at Shutdown (Note 15) I

(SD IN

) ≥ 1µA 200 200

Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the device outside of its rated operating conditions.

Note 2: The maximum allowable power dissipation is a function of the maximum junction temperature, T

(max), the junction-to-ambient thermal resistance, θ

J-A

and the ambient temperature, T

. The maximum allowable power dissipation at any ambient temperature is calculated using: P(max)

Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. SeeApplication Hints for additional information on heat sinking and thermal resistance.

Note 3: When used in dual-supply systems where the regulator load is returned to a negative supply, the output voltage must be diode-clamped to ground. Note 4: May exceed the input supply voltage. Note 5: Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 6: Load regulation is measured at constant junction temperature using low duty cycle pulse testing. Twoseparate tests are performed, one for the range of 100

µA to 1 mA and one for the 1 mA to 250 mA range. Changes in output voltage due to heating effects are covered by the thermal regulation specification. Note 7: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below the value measured with a 1V differential. At

very low values of programmed output voltage, the input voltage minimum of 2V (2.3V over temperature) must be observed. Note 8: Thermal regulation is the change in output voltage at a time T after a change in power dissipation, excluding load or line regulation effects. Specifications

are for a 200 mA load pulse at V

20V (3W pulse) for T=10 ms on the Main regulator output. For the Auxiliary regulator output, specifications are for a 66 mA

load pulse at V

20V (1W pulse) for T=10 ms.

Note 9: Connect a 0.1 µF capacitor from the output to the feedback pin. Note 10: Load regulation is measured at constant junction temperature using low duty cycle pulse testing. Two separate tests are performed, one for the range of

100 µA to 1 mA and one for the 1 mA to 75 mA range. Changes in output voltage due to heating effects are covered by the thermal regulation specification. Note 11: Dropout dectection comparator thresholds are expressed as changes in a 5V output. To express the threshold voltages in terms of a differential at the

Feedback terminal, divide by the error amplifier gain=V

OUT/VREF

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