National Semiconductor LMX2978 Technical data

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LP2978
Micropower SOT, 50 mA Low-Noise Ultra Low-Dropout
Regulator

Designed for Use with Very Low ESR Output Capacitors

LP2978 Micropower SOT, 50 mA Low-Noise Ultra Low-Dropout Regulator

March 2005

General Description

The LP2978 is a 50 mA, fixed-output voltage regulator de­signed to provide ultra low-dropout and low noise in battery
powered applications.

™

Using an optimized VIP
cess, the LP2978 delivers unequalled performance in all
specifications critical to battery-powered designs:

Dropout Voltage: Typically 120 mV

@

1 mA load.

Ground Pin Current: Typically 350 µA

@

75 µA
Enhanced Stability: The LP2978 is stable with output ca-

pacitor ESR as low as 5 mΩ, which allows the use of ceramic
capacitors on the output.

Sleep Mode: Less than 1 µA quiescent current when ON/
OFF pin is pulled low.

Smallest Possible Size: SOT-23 package uses absolute
minimum board space.

Precision Output: 1% tolerance output voltages available
(A grade).

Low Noise: By adding a 10 nF bypass capacitor, output
noise can be reduced to 30 µV (typical).

1 mA load.

(Vertically Integrated PNP) pro-

@

50 mA load, and 7 mV

@

50 mA load, and

Block Diagram

Features

n Ultra low dropout voltage
n Smallest possible size (SOT-23 Package)
n Requires minimum external components
n Stable with low-ESR output capacitor

<

n

1 µA quiescent current when shut down

n Low ground pin current at all loads
n Output voltage accuracy 1% (A Grade)
n High peak current capability
n Wide supply voltage range (16V max)
n Low Z
n Overtemperature/overcurrent protection
n −40˚C to +125˚C junction temperature range
n Custom voltages available

: 0.3Ω typical (10 Hz to 1 MHz)

OUT

Applications

n Cellular Phone
n Palmtop/Laptop Computer
n Personal Digital Assistant (PDA)
n Camcorder, Personal Stereo, Camera

10093501

VIP™is a trademark of National Semiconductor Corporation.

© 2005 National Semiconductor Corporation DS100935 www.national.com

Basic Application Circuit

LP2978

*ON/OFF input must be actively terminated. Tie to VINif this function is not to be used.

**Minimum capacitance is shown to ensure stability (may be increased without limit). Ceramic capacitor required for output (see Application Hints).

***Reduces output noise (may be omitted if application is not noise critical). Use ceramic or film type with very low leakage current (see Application Hints).

10093502

Connection Diagram

See NS Package Number MF05A

10093503

Ordering Information

TABLE 1. Package Marking and Ordering Information

Output Voltage (V) Grade Order Information Package Marking Supplied As:

3.8 A LP2978AIM5X-3.8 LØLA 3000 Units on Tape and Reel

3.8 A LP2978AIM5-3.8 LØLA 1000 Units on Tape and Reel

3.8 STD LP2978IM5X-3.8 LØLB 3000 Units on Tape and Reel

3.8 STD LP2978IM5-3.8 LØLB 1000 Units on Tape and Reel

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LP2978

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 Temp. (Soldering, 5 sec.) 260˚C

Input Supply Voltage (Survival) −0.3V to +16V

Input Supply Voltage (Operating) 2.5V to +16V

Shutdown Input Voltage (Survival) −0.3V to +16V

Output Voltage (Survival, (Note 4)) −0.3V to +9V

I

(Survival) Short Circuit

OUT

Protected

Input-Output Voltage (Survival, −0.3V to +16V

(Note 5))

ESD Rating (Note 2) 2 kV

Power Dissipation (Note 3) Internally Limited

Electrical Characteristics

Limits in standard typeface are for TJ= 25˚C. and limits in boldface type apply over the full operating temperature range. Un­less otherwise specified: V

(NOM) + 1V, IL= 1 mA, CIN= 1 µF, C

IN=VO

Symbol Parameter Conditions Typ

∆V

O

Output Voltage
Tolerance

IL= 1 mA −1.0 1.0 −1.5 1.5

1mA≤ IL≤ 50 mA −1.5 1.5 −2.5 2.5

Output Voltage VO(NOM)+1V ≤ VIN≤ 16V 0.007 0.014 0.014

Line Regulation 0.032 0.032

V

IN–VO

Dropout Voltage

IL=0 1 3 3

(Note 7)

I

= 1 mA 7 10 10

L

I

=10mA 40 60 60

L

I

= 50 mA 120 150 150

L

I

GND

V

ON/OFF

I

ON/OFF

e

n

(SC) Short Circuit Current RL= 0 (Steady State) 400 mA

I

O

I

(PK) Peak Output Current V

O

Ground Pin Current IL= 0 65 95 95

I

= 1 mA 75 110 110

L

I

= 10 mA 120 220 220

L

I

= 50 mA 350 600 600

L

<

ON/OFF

ON/OFF

ON/OFF

ON/OFF

0.3V 0.01 0.8 0.8

<

0.15V 0.05 2 2

= 0 0.01 −2 −2

=5V 5 15 15

ON/OFF Input Voltage
(Note 8)

ON/OFF Input Current V

V

V

High = O/P ON 1.4 1.6 1.6

Low = O/P OFF 0.55 0.15 0.15

V

Output Noise BW = 300 Hz to 50 kHz,

Voltage (RMS) C

Ripple Rejection f = 1 kHz, C

=10µF 30 µV

OUT

C

C

=10nF

BYPASS

=10nF

BYPASS

=10µF

OUT

≥ Vo(NOM) −5% 350 mA

OUT

= 4.7 µF, V

OUT

ON/OFF

= 2V.

LP2978AI-X.X LP2978I-X.X

Min Max Min Max

−2.5 2.5 −3.5 3.5

55

15 15

90 90

225 225

125 125

170 170

400 400

1000 1000

45 dB

Units(Note 6) (Note 6)

%V

NOM

%/V

mV

µA

V

µA

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