National Semiconductor LP3853, LP3856 Technical data

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LP3853/LP3856
3A Fast Response Ultra Low Dropout Linear Regulators

LP3853/LP3856 3A Fast Ultra Low Dropout Linear Regulators

March 2004

General Description

The LP3853/LP3856 series of fast ultra low-dropout linear
regulators operate from a +2.5V to +7.0V input supply. Wide
range of preset output voltage options are available. These
ultra low dropout linear regulators respond very quickly to
step changes in load, which makes them suitable for low
voltage microprocessor applications. The LP3853/LP3856
are developed on a CMOS process which allows low quies­cent current operation independent of output load current.
This CMOS process also allows the LP3853/LP3856 to op­erate under extremely low dropout conditions.

Dropout Voltage: Ultra low dropout voltage; typically 39mV
at 300mA load current and 390mV at 3A load current.

Ground Pin Current: Typically 4mA at 3A load current.
Shutdown Mode: Typically 10nA quiescent current when

the shutdown pin is pulled low.
Error Flag: Error flag goes low when the output voltage

drops 10% below nominal value.

SENSE: Sense pin improves regulation at remote loads.
Precision Output Voltage: Multiple output voltage options

are available ranging from 1.8V to 5.0V with a guaranteed
accuracy of
conditions (varying line, load, and temperature).

±

1.5% at room temperature, and±3.0% over all

Features

n Ultra low dropout voltage
n Stable with selected ceramic capacitors
n Low ground pin current
n Load regulation of 0.08%
n 10nA quiescent current in shutdown mode
n Guaranteed output current of 3A DC
n Available in TO-263 and TO-220 packages
n Output voltage accuracy
n Error flag indicates output status
n Sense option improves load regulation
n Overtemperature/overcurrent protection
n −40˚C to +125˚C junction temperature range

±

1.5%

Applications

n Microprocessor power supplies
n Stable with ceramic output capacitors
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

Typical Application Circuits

**SD and ERROR pins must be pulled high through a 10kΩ pull-up resistor. Connect the ERROR pin to ground if this function is not used. See Application Hints
for more information.

20030901

© 2004 National Semiconductor Corporation DS200309 www.national.com

Typical Application Circuits (Continued)

LP3853/LP3856

**SD pin must be pulled high through a 10kΩ pull-up resistor. See Application Hints for more information.

Connection Diagrams

Top View

TO220-5 Package

Bent, Staggered Leads

20030905

Top View

TO263-5 Package

Pin Description for TO220-5 and TO263-5 Packages

#

Pin

Name Function Name Function

1SD

2V

IN

3 GND Ground GND Ground

4V

OUT

5 ERROR

LP3853 LP3856

Shutdown SD Shutdown

Input Supply V

Output Voltage V

IN

OUT

ERROR Flag SENSE Remote Sense Pin

20030934

20030906

Input Supply

Output Voltage

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Ordering Information

LP3853/LP3856

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

TABLE 1. Package Marking and Ordering Information

Output

Voltage Order Number

5.0 LP3853ES-5.0 3A, Error Flag

5.0 LP3853ESX-5.0 3A, Error Flag

3.3 LP3853ES-3.3 3A, Error Flag

3.3 LP3853ESX-3.3 3A, Error Flag

2.5 LP3853ES-2.5 3A, Error Flag

2.5 LP3853ESX-2.5 3A, Error Flag

1.8 LP3853ES-1.8 3A, Error Flag

1.8 LP3853ESX-1.8 3A, Error Flag

5.0 LP3856ES-5.0 3A, SENSE TO263-5 LP3856ES-5.0 Rail

5.0 LP3856ESX-5.0 3A, SENSE TO263-5 LP3856ES-5.0 Tape and Reel

3.3 LP3856ES-3.3 3A, SENSE TO263-5 LP3856ES-3.3 Rail

3.3 LP3856ESX-3.3 3A, SENSE TO263-5 LP3856ES-3.3 Tape and Reel

2.5 LP3856ES-2.5 3A, SENSE TO263-5 LP3856ES-2.5 Rail

2.5 LP3856ESX-2.5 3A, SENSE TO263-5 LP3856ES-2.5 Tape and Reel

1.8 LP3856ES-1.8 3A, SENSE TO263-5 LP3856ES-1.8 Rail

1.8 LP3856ESX-1.8 3A, SENSE TO263-5 LP3856ES-1.8 Tape and Reel

5.0 LP3853ET-5.0 3A, Error Flag

3.3 LP3853ET-3.3 3A, Error Flag

2.5 LP3853ET-2.5 3A, Error Flag

1.8 LP3853ET-1.8 3A, Error Flag

5.0 LP3856ET-5.0 3A, SENSE TO220-5 LP3856ET-5.0 Rail

3.3 LP3856ET-3.3 3A, SENSE TO220-5 LP3856ET-3.3 Rail

2.5 LP3856ET-2.5 3A, SENSE TO220-5 LP3856ET-2.5 Rail

1.8 LP3856ET-1.8 3A, SENSE TO220-5 LP3856ET-1.8 Rail

Description

(Current, Option)

Package

Type Package Marking Supplied As:

TO263-5 LP3853ES-5.0 Rail

TO263-5 LP3853ES-5.0 Tape and Reel

TO263-5 LP3853ES-3.3 Rail

TO263-5 LP3853ES-3.3 Tape and Reel

TO263-5 LP3853ES-2.5 Rail

TO263-5 LP3853ES-2.5 Tape and Reel

TO263-5 LP3853ES-1.8 Rail

TO263-5 LP3853ES-1.8 Tape and Reel

TO220-5 LP3853ET-5.0 Rail

TO220-5 LP3853ET-3.3 Rail

TO220-5 LP3853ET-2.5 Rail

TO220-5 LP3853ET-1.8 Rail

20030931

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Block Diagrams

LP3853/LP3856

LP3853

20030903

LP3856

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20030929

LP3853/LP3856

Absolute Maximum Ratings (Note 1)

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

I

(Survival) Short Circuit Protected

OUT

Maximum Voltage for ERROR
Pin V

Maximum Voltage for SENSE Pin V

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

Lead Temperature

Operating Ratings

(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 (Note 11) 2.5V to 7.0V

Shutdown Input Voltage −0.3V to 7.0V

Maximum Operating Current (DC) 3A

Junction Temperature −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
LP3853/LP3856

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)

+ 1V, IL= 10 mA, C

Symbol Parameter Conditions Typ

Output Voltage

V

O

Tolerance

+1V ≤ VIN≤ 7.0V

V

OUT

10 mA ≤ I

≤ 3A 0

L

(Note 8)

∆V

OL

Output Voltage Line

V

+1V ≤ VIN≤ 7.0V 0.02

OUT

Regulation (Note 8)

∆V

/ ∆I

O

OUT

Output Voltage Load

10 mA ≤ I

≤ 3A 0.08

L

Regulation
(Note 8)

I

V

IN-VOUT

= 300 mA 39 50

L

Dropout Voltage

I

GND

I

GND

I

O(PK)

(Note 10)

Ground Pin Current In
Normal Operation Mode

Ground Pin Current In
Shutdown Mode

Peak Output Current VO≥ V

IL= 3A 390 450

I

= 300 mA 4 9

L

=3A 4 9

I

L

VSD≤ 0.3V 0.01 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)

0.06

0.14

LP3853/6 (Note 5) Units

Min Max

-1.5

-3.0

+1.5

+3.0

65

600

10

10

IN

OUT

%

%

%

mV

mA

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Electrical Characteristics
LP3853/LP3856

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

LP3853/LP3856

Symbol Parameter Conditions Typ

Shutdown Input

V

SDT

T

dOFF

T

dON

I

SD

Error Flag

V

T

V

TH

V

EF(Sat)

Td Flag Reset Delay 1 µs

I

lk

I

max

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. The line and load regulation specification contains only
the typical number. However, the limits for line and load regulation are included in the output voltage tolerance specification.

Note 9: Error Flag threshold and hysteresis are specified as percentage of regulated output voltage. See Application Hints.

Note 10: 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 11: The minimum operating value for V

2

2

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

Shutdown Threshold

Turn-off delay IL=3A 20 µs

Turn-on delay IL=3A 25 µs

SD Input Current VSD=V

Threshold (Note 9) 10 516%

Threshold Hysteresis (Note 9) 5 28%

Error Flag Saturation I

Error Flag Pin Leakage
Current

Error Flag Pin Sink
Current

Output Noise Density f = 120Hz 0.8 µV

Output Noise Voltage

, 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

(Continued)

IN=VO(NOM)

IN

+ 1V, IL= 10 mA, C

Output = High V

Output = Low 0 0.3

= 100µA 0.02 0.1 V

sink

V

Error

V

IN=VOUT

C

OUT

V

OUT

V

IN=VOUT

C

OUT

V

OUT

BW = 10Hz – 100kHz
V

OUT

BW = 300Hz – 300kHz
V

OUT

is equal to either [V

= 10µF, VSD= 2V.

OUT

LP3853/6 (Note 5) Units

(Note

4)

IN

IN

1nA

Min Max

2

1nA

= 0.5V 1mA

+1V

73
= 10uF
= 3.3V, f = 120Hz

+ 0.5V

57
= 10uF
= 3.3V, f = 120Hz

150

= 2.5V

100

= 2.5V

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.

V

dB

µV (rms)

= 50˚C/W

jA

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