National Semiconductor LP2954, LP2954A Technical data

LP2954/LP2954A 5V and Adjustable Micropower Low-Dropout Voltage Regulators

April 2005

General Description

The LP2954 is a 5V micropower voltage regulator with very low quiescent current (90 µA typical at 1 mA load) and very low dropout voltage (typically 60 mV at light loads and 470 mV at 250 mA load current).

The quiescent current increases only slightly at dropout (120 µA typical), which prolongs battery life.

The LP2954 with a fixed 5V output is available in the threelead TO-220 and TO-263 packages. The adjustable LP2954 is provided in an 8-lead surface mount, small outline package. The adjustable version also provides a resistor network which can be pin strapped to set the output to 5V.

Reverse battery protection is provided. The tight line and load regulation (0.04% typical), as well as

very low output temperature coefficient make the LP2954 well suited for use as a low-power voltage reference.

Output accuracy is guaranteed at both room temperature and over the entire operating temperature range.

Package Outline and Ordering Information

TO-220 3– Lead Plastic Package

Features

n 5V output within 1.2% over temperature (A grade) n Adjustable 1.23 to 29V output voltage available

(LP2954IM and LP2954AIM)

n Guaranteed 250 mA output current n Extremely low quiescent current n Low dropout voltage n Reverse battery protection n Extremely tight line and load regulation n Very low temperature coefficient n Current and thermal limiting n Pin compatible with LM2940 and LM340 (5V version

only)

n Adjustable version adds error flag to warn of output drop

and a logic-controlled shutdown

Applications

n High-efficiency linear regulator n Low dropout battery-powered regulator

TO-263 3-Lead Plastic Surface-Mount Package

Top View

Front View

Order Number LP2954AIT or LP2954IT

See NS Package T03B

SO-8 Small Outline Surface Mount

Top View

Order Number LP2954AIM or LP2954IM

See NS Package M08A

01112802

Side View

Order Number LP2954AIS or LP2954IS

See NS Package TS3B

01112833

01112809

01112810

Ordering Information

Order Number Temp. Range Package NS Package

) ˚C (JEDEC) Number

LP2954AIT −40 to +125 TO-220 TO3B

LP2954IT

LP2954AIS −40 to +125 TO-263 TS3B

LP2954/LP2954A 5V

LP2954IS

LP2954AIM −40 to +125 SO-8 M08A

LP2954IM

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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.

Operating Junction Temperature

Range

LP2954AI/LP2954I −40˚C to +125˚C

Electrical Characteristics

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

Lead Temperature

(Soldering, 5 seconds) 260˚C

Power Dissipation (Note 2) Internally Limited

Input Supply Voltage −20V to +30V

ESD Rating 2 kV

Electrical Characteristics (Continued)

Limits in standard typeface are for TJ= 25˚C, bold typeface applies over the −40˚C to +125˚C temperature range. Limits are guaranteed by production testing or correlation techniques using standard Statistical Quality Control (SQC) methods. Unless otherwise noted: V

Symbol Parameter Conditions Typical 2954AI 2954I Units

LP2954/LP2954A 5V

Output Noise CL= 2.2 µF 400 µV RMS

Voltage

(10 Hz to 100 kHz) C

= 100 mA

Additional Specifications for the Adjustable Device (LP2954AIM and LP2954IM)

∆V

REF

Reference Voltage (Note 10) 1.230 1.215

REF

Reference Voltage

REF

Line Regulation

REF

/∆T Reference Voltage

Temperature Coefficient

(FB) Feedback Pin Bias

Current

GND

Ground Pin Current at Shutdown (Note 6)

(SINK) Output "OFF"

Pulldown Current

Dropout Detection Comparator

Output "HIGH" Leakage Current

THR

Output "LOW" Voltage VIN=VO(NOM)−0.5V

(MAX) Upper Threshold

Voltage

(MIN) Lower Threshold

THR

Voltage

HYST Hysteresis (Note 13) 15 mV

Shutdown Input

Input Offset Voltage (Referred to V

HYST Hysteresis 6 mV

Input Bias Current VIN(S/D)=0V to 5V 10 −30

= 6V, IL= 1 mA, CL= 2.2 µF.

=33µF 260

=33µF(Note 9) 80

VIN=2.5V to VO(NOM)+1V

VIN=2.5V to VO(NOM)+1V to 30V (Note 11)

(Note 3) 20 ppm/˚C

SHUTDOWN

≤1.1V 105 140 140 µA

(Note 12) 30

VOH=30V 0.01 1

(COMP)=400µA

(Note 13) −60 −80

(Note 13) −85 −110

REF

Min Max Min Max

1.205

1.245

1.255

1.205

1.190

1.255

1.270

0.03 0.1 0.2 %

0.2 0.4 %

20 40

150 250

400

−35

−95

−25

−55

−160

)

3 −7.5

−10

−40

7.5

−50

−80

−95

−110

−160

−7.5

−10

−30

−50

250

400

−35

−25

−55

−40

7.5

µA

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Electrical Characteristics (Continued)

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 and the ambient temperature, T

Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The junction-toambient thermal resistance of the TO-220 (without heatsink) is 60˚C/W, 73˚C/W for the TO-263, and 160˚C/W for the SO-8. If the TO-263 package is used, the thermal resistance can be reduced by increasing the P.C. board copper area thermally connected to the package: Using 0.5 square inches of copper area, θ 50˚C/W; with 1 square inch of copper area, θ is 3˚C/W. If an external heatsink is used, the effective junction-to-ambient thermal resistance is the sum of the junction-to-case resistance (3˚C/W), the specified thermal resistance of the heatsink selected, and the thermal resistance of the interface between the heatsink and the LP2954. Some typical values are listed for interface materials used with TO-220:

TABLE 1. Typical Values of Case-to-Heatsink

Thermal Resistance (˚C/W) (Data from AAVID Eng.)

. The maximum allowable power dissipation at any ambient temperature is calculated using:

is 37˚C/W; and with 1.6 or more square inches of copper area, θJAis 32˚C/W. The junction-to-case thermal resistance

TABLE 2. Typical Values of Case-to-Heatsink

Thermal Resistance (˚C/W) (Data from Thermalloy)

Silicone grease 1.0

Dry interface 1.3

Mica with grease 1.4

Note 3: Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.

Note 4: Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested separately for load regulation in the load

ranges 0.1 mA–1 mA and 1 mA–250 mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.

Note 5: 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.

Note 6: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current plus the ground pin current.

Note 7: Thermal regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or line regulation

effects. Specifications are for 200 mA load pulse at V

Note 8: 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 9: Connect a 0.1µF capacitor from the output to the feedback pin.

Note 10: V

Note 11: Two seperate tests are performed, one covering V

Note 12: V

Note 13: Comparator thresholds are expressed in terms of a voltage differential at the Feedback terminal below the nominal reference voltage measured at

Note 14: Human body model, 200pF discharged through 1.5kΩ.

REF≤VOUT

SHUTDOWN

(NOM)+1V. To express these thresholds in terms of output voltage change, multiply by the Error amplifier gain, which is V

IN=VO

≤(VIN−1V), 2.3V≤VIN≤30V, 100µA≤IL≤250mA.

≤1.1V, VOUT=VO(NOM).

= 20V (3W pulse) for T = 10 ms.

=2.5V to VO(NOM)+1V and the other test for VIN=2.5V to VO(NOM)+1V to 30V.

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

Thermasil III 1.3

Thermasil II 1.5

Thermalfilm (0.002) with grease 2.2

=(R1+R2)/R2.

OUT/VREF

J-A

LP2954/LP2954A 5V

Typical Performance Characteristics

Quiescent Current Quiescent Current

01112812 01112813

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