National Semiconductor LP3876-ADJ Technical data

查询LP3876-ADJ供应商

LP3876-ADJ
3A Fast Ultra Low Dropout Linear Regulator

LP3876-ADJ 3A Fast Ultra Low Dropout Linear Regulator

September 2003

General Description

The LP3876-ADJ fast ultra low-dropout linear regulators op­erate from a +2.5V to +7.0V input supply. These ultra low
dropout linear regulators respond very quickly to step
changes in load, which makes them suitable for low voltage
microprocessor applications. The LP3876-ADJ is developed
on a CMOS process which allows low quiescent current
operation independent of output load current. This CMOS
process also allows the LP3876-ADJ to operate under ex­tremely low dropout conditions.

Dropout Voltage: Ultra low dropout voltage; typically 80mV
at 300mA load current and 800mV at 3A load current.

Ground Pin Current: Typically 6mA at 3A load current.
Shutdown Mode: Typically 1µA quiescent current when the

shutdown pin is pulled low.
Adjustable Output Voltage: The output voltage may be

programmed via two external resistors.

Typical Application Circuit

Features

n Ultra low dropout voltage
n Low ground pin current
n Load regulation of 0.08%
n 1µA quiescent current in shutdown mode
n Guaranteed output current of 3A DC
n Available in TO-263 and TO-220 packages
n Minimum output capacitor requirements
n Overtemperature/overcurrent protection
n −40˚C to +125˚C junction temperature range

Applications

n Microprocessor power supplies
n GTL, GTL+, BTL, and SSTL bus terminators
n Power supplies for DSPs
n SCSI terminator
n Post regulators
n High efficiency linear regulators
n Battery chargers
n Other battery powered applications

*See Application Hints

© 2003 National Semiconductor Corporation DS200744 www.national.com

20074445

Connection Diagrams

LP3876-ADJ

Top View

20074405

TO220-5 Package

Bent, Staggered Leads

Pin Description for TO220-5 and TO263-5 Packages

Pin #

Name Function

1SD

2V

IN

3 GND Ground

4V

OUT

5 ADJ Set Output Voltage

LP3876-ADJ

Ordering Information

Top View

20074406

TO263-5 Package

Shutdown

Input Supply

Output Voltage

Package Type Designator is "T" for TO220 package, and "S" for TO263 package.

20074431

TABLE 1. Package Marking and Ordering Information

Output

Voltage Order Number

Current

Description Package Type Package Marking Supplied As:

ADJ LP3876ES-ADJ 3A TO263-5 LP3876ES-ADJ Rail

ADJ LP3876ESX-ADJ 3A TO263-5 LP3876ES-ADJ Tape and Reel

ADJ LP3876ET-ADJ 3A TO220-5 LP3876ET-ADJ Rail

www.national.com 2

Block Diagram LP3876-ADJ

LP3876-ADJ

20074429

www.national.com3

Absolute Maximum Ratings (Note 1)

I

(Survival) Short Circuit Protected

OUT

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

LP3876-ADJ

Operating Ratings

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

Lead Temperature

(Soldering, 5 sec.) 260˚C

ESD Rating (Note 3) 2 kV

Power Dissipation (Note 2) Internally Limited

Input Supply Voltage (Survival) −0.3V to +7.5V

Shutdown Input Voltage

Input Supply Voltage (Operating),
(Note 10) 2.5V to 7.0V

Shutdown Input Voltage
(Operating) −0.3V to 7.0V

Maximum Operating Current (DC) 3A

Operating Junction Temp. Range −40˚C to +125˚C

(Survival) −0.3V to 7.5V

Output Voltage (Survival), (Note

6), (Note 7) −0.3V to +6.0V

Electrical Characteristics
LP3876-ADJ

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

IN=VO(NOM)

+ 1.5V, IL= 10 mA, C

Symbol Parameter Conditions Typ

V

+1.5V ≤ VIN≤ 7V

V

∆V

ADJ

I

ADJ

OL

Adjust Pin Voltage

Adjust Pin Input Current V

Output Voltage Line

OUT

10 mA ≤ I

OUT

10 mA ≤ I

V

OUT

≤ 3A

L

+1.5V ≤ VIN≤ 7V

≤ 3A

L

+1.5V ≤ VIN≤ 7.0V 0.02

Regulation (Note 8)

∆V

/ ∆I

O

OUT

Output Voltage Load

10 mA ≤ I

≤ 3A 0.08

L

Regulation
(Note 8)

= 300 mA 80 105

V

IN-VOUT

I

L

Dropout Voltage

I

I

I

O(PK)

GND

GND

(Note 9)

Ground Pin Current In
Normal Operation Mode

Ground Pin Current In
Shutdown Mode

Peak Output Current VO≥ V

IL= 3A 800 1000

= 300 mA 5 9

I

L

IL=3A 6 14

VSD≤ 0.3V 1 10 µA

-40˚C ≤T

≤ 85˚C 50

J

- 4% 4.5 A

O(NOM)

SHORT CIRCUIT PROTECTION

I

SC

Short Circuit Current 6 A

= 10µF, VSD= 2V.

OUT

(Note 4)

LP3876-ADJ (Note 5) Units

Min Max

1.216

1.198

1.180

1.234

1.253

10 100 nA

0.06

0.14

125

1200

10

15

V

%

%

mV

mA

www.national.com 4

Electrical Characteristics
LP3876-ADJ

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

Symbol Parameter Conditions Typ

SHUTDOWN INPUT

V

SDT

T

dOFF

T

dON

I

SD

AC PARAMETERS

PSRR Ripple Rejection

ρ

n(l/f

e

n

Note 1: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions for which the device is
intended to be functional, but does not guarantee specific performance limits. For guaranteed specifications and test conditions, see Electrical Characteristics. The
guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed
test conditions.

Note 2: At elevated temperatures, devices must be derated based on package thermal resistance. The devices in TO220 package must be derated at θ
(with 0.5in

0.5in

Note 3: The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin.

Note 4: Typical numbers are at 25˚C and represent the most likely parametric norm.

Note 5: Limits are guaranteed by testing, design, or statistical correlation.

Note 6: If used in a dual-supply system where the regulator load is returned to a negative supply, the output must be diode-clamped to ground.

Note 7: The output PMOS structure contains a diode between the V

if the voltage at the output terminal is forced to be higher than the voltage at the input terminal. This diode can typically withstand 200mA of DC current and 1Amp
of peak current.

Note 8: Output voltage line regulation is defined as the change in output voltage from the nominal value due to change in the input line voltage. Output voltage load
regulation is defined as the change in output voltage from the nominal value due to change in load current.

Note 9: Dropout voltage is defined as the minimum input to output differential voltage at which the output drops 2% below the nominal value. Dropout voltage
specification applies only to output voltages of 2.5V and above. For output voltages below 2.5V, the drop-out voltage is nothing but the input to output differential,
since the minimum input voltage is 2.5V.

Note 10: The minimum operating value for V

2

, 1oz. copper area), junction-to-ambient (with no heat sink). The devices in the TO263 surface-mount package must be derated at θjA= 60˚C/W (with

2

, 1oz. copper area), junction-to-ambient. See Application Hints.

(Continued)

IN=VO(NOM)

+ 1.5V, IL= 10 mA, C

= 10µF, VSD= 2V.

OUT

LP3876-ADJ (Note 5) Units

Shutdown Threshold

(Note 4)

Output = High V

IN

Output = Low 0 0.3

Min Max

2

V

Turn-off delay IL=3A 20 µs

Turn-on delay IL=3A 25 µs

SD Input Current VSD=V

V

IN=VOUT

= 10uF

C

OUT

= 3.3V, f = 120Hz

V

OUT

V

IN=VOUT

= 10uF

C

OUT

= 3.3V, f = 120Hz

V

OUT

IN

+1V

+ 0.5V

1nA

73

57

dB

Output Noise Density f = 120Hz 0.8 µV

150

100

µV (rms)

= 50˚C/W

jA

Output Noise Voltage

BW = 10Hz – 100kHz
V

BW = 300Hz – 300kHz
V

is equal to either [V

IN

= 2.5V

OUT

= 2.5V

OUT

and V

IN

OUT(NOM)+VDROPOUT

terminals. This diode is normally reverse biased. This diode will get forward biased

OUT

] or 2.5V, whichever is greater.

LP3876-ADJ

www.national.com5