National Semiconductor LP38500 Technical data

May 19, 2008

LP38500/2-ADJ, LP38500A/2A-ADJ

1.5A FlexCap Low Dropout Linear Regulator for 2.7V to

5.5V Inputs

LP38500/2-ADJ, LP38500A/2A-ADJ 1.5A FlexCap Low Dropout Linear Regulator for 2.7V to 5.5V

Inputs

General Description

National's FlexCap LDO's feature unique compensation that allows the use of any type of output capacitor with no limits on minimum or maximum ESR. The LP38500/2 series of lowdropout linear regulators operates from a +2.7V to +5.5V 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. Developed on a CMOS process, (utilizing a PMOS pass transistor), the LP38500/2 has low quiescent current that changes little with load current.

Ground Pin Current: Typically 2 mA at 1.5A load current. Disable Mode: Typically 25 nA quiescent current when the

Enable pin is pulled low. Simplified Compensation: Stable with any type of output

capacitor, regardless of ESR. Precision Output: "A" grade versions available with 1.5%

tolerance (25°C) and 3% over line, load and tempera-

ADJ

ture.

Typical Application Circuit

Features

FlexCap: Stable with ceramic, tantalum, or aluminum

■

capacitors Stable with 10 µF input/output capacitor

■

Adjustable output voltage from 0.6V to 5V

■

Low ground pin current

■

25 nA quiescent current in shutdown mode

■

Guaranteed output current of 1.5A

■

Available in TO-263, TO-263 THIN, and LLP-8 packages

■

Guaranteed V

■

Guaranteed accuracy of ±3.5% @ 25°C (STD)

■

Over-Temperature and Over-Current protection

■

−40°C to +125°C operating TJ range

■

Enable pin (LP38502)

■

accuracy of ±1.5% @ 25°C (A Grade)

ADJ

Applications

ASIC Power Supplies In:

■

Printers, Graphics Cards, DVD Players Set Top Boxes, Copiers, Routers

DSP and FPGA Power Supplies

■

SMPS Regulator

■

Conversion from 3.3V or 5V Rail

■

30036119

Connection Diagrams for TO-263 (TS) Package

Top View (LP38500TS-ADJ)

TO-263 Package

30036121

Top View (LP38502TS-ADJ)

TO-263 Package

LP38500/2-ADJ, LP38500A/2A-ADJ

Connection Diagrams for TO-263 THIN (TJ) Package

Top View (LP38500TJ-ADJ, LP38500ATJ-ADJ)

TO-263 THIN Package

30036163

Top View (LP38502TJ-ADJ, LP38502ATJ-ADJ)

TO-263 THIN Package

Pin Descriptions for TO-263 (TS), TO-263 THIN (TJ) Packages

Pin # Designation Function

N/C

2 IN Input Supply

3 GND Ground

4 OUT Regulated Output Voltage

5 ADJ Sets output voltage

DAP DAP

Enable (LP38502 only). Pull high to enable the output, low to disable the output. This pin has no internal bias and must be either tied to the input voltage, or actively driven.

In the LP38500, this pin has no internal connections. It can be left floating or used for trace routing.

The DAP is used to remove heat from the device by conducting it to the copper clad area on the PCB which acts as the heatsink. The DAP is electrically connected to the backside of the die. The DAP must be connected to ground potential, but can not be used as the only ground connection.

30036122

30036162

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Connection Diagrams for LLP-8 (SD) Package

LP38500/2-ADJ, LP38500A/2A-ADJ

Top View (LP38500SD-ADJ, LP38500ASD-ADJ)

LLP-8 Package

30036159

Pin Descriptions for LLP-8 (SD) Package

Pin # Designation Function

1 GND Ground

3, 4 IN

5, 6, 7 OUT

8 ADJ Sets output voltage

DAP DAP

Input Supply (LP38500 only). Input Supply pins share current and must be connected together on the PC Board.

Enable (LP38502 only). Pull high to enable the output, low to disable the output. This pin has no internal bias and must be either tied to the input voltage, or actively driven.

Input Supply. Input Supply pins share current and must be connected together on the PC Board.

Regulated Output Voltage. Output pins share current and must be connected together on the PC Board.

The DAP is used to remove heat from the device by conducting it to a copper clad area on the PCB which acts as a heatsink. The DAP is electrically connected to the backside of the die. The DAP must be connected to ground potential, but can not be used as the only ground connection.

Ordering Information

Top View (LP38502SD-ADJ, LP38502ASD-ADJ)

LLP-8 Package

30036160

Output

Voltage

ADJ

TABLE 1. Package Marking and Ordering Information

Order Number

LP38500SDX-ADJ

LP38500SD-ADJ LP38500SD-ADJ Tape and Reel of 1000 Units

LP38502SDX-ADJ LP38502SD-ADJ Tape and Reel of 4500 Units

LP38502SD-ADJ LP38502SD-ADJ Tape and Reel of 1000 Units

LP38500ASDX-ADJ LP38500ASD-ADJ Tape and Reel of 4500 Units

LP38500ASD-ADJ LP38500ASD-ADJ Tape and Reel of 1000 Units

LP38502ASDX-ADJ LP38502ASD-ADJ Tape and Reel of 4500 Units

LP38502ASD-ADJ LP38502ASD-ADJ Tape and Reel of 1000 Units

LP38500TSX-ADJ

LP38500TS-ADJ LP38500TS-ADJ Rail of 45 Units

LP38502TSX-ADJ LP38502TS-ADJ Tape and Reel of 500 Units

LP38502TS-ADJ LP38502TS-ADJ Rail of 45 Units

LP38500TJ-ADJ

LP38502TJ-ADJ LP38502TJ-ADJ Tape and Reel of 1000 Units

LP38500ATJ-ADJ LP38500ATJ-ADJ Tape and Reel of 1000 Units

LP38502ATJ-ADJ LP38502ATJ-ADJ Tape and Reel of 1000 Units

Package Type Package Marking Supplied As:

LP38500SD-ADJ Tape and Reel of 4500 Units

LLP-8

LP38500TS-ADJ Tape and Reel of 500 Units

TO-263

LP38500TJ-ADJ Tape and Reel of 1000 Units

TO-263 THIN

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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 Lead Temperature (Soldering, 5 sec.) 260°C

Operating Ratings (Note 1)

Input Supply Voltage 2.7V to 5.5V Enable Input Voltage 0.0V to 5.5V Output Current (DC) 0 to 1.5A Junction Temperature(Note 3) −40°C to +125°C V

OUT

ESD Rating (Note 2) ±2 kV Power Dissipation(Note 3) Internally Limited Input Pin Voltage (Survival) −0.3V to +6.0V Enable Pin Voltage (Survival) −0.3V to +6.0V Output Pin Voltage (Survival) −0.3V to +6.0V I

(Survival)

OUT

Internally Limited

LP38500/2-ADJ, LP38500A/2A-ADJ

Electrical Characteristics LP38500/2–ADJ

Unless otherwise specified: VIN = 3.3V, I are for TJ = 25°C only; limits in boldface type apply over the junction temperature (TJ) range of -40°C to +125°C. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only.

Symbol Parameter Conditions Min Typ Max Units

ADJ

Adjust Pin Voltage (Note 6)

Adjust Pin Voltage (Note 6) "A" GRADE

Adjust Pin Bias Current

Dropout Voltage (Note 7)

Output Voltage Line

/ΔV

Regulation

ΔV

OUT

(Notes 4, 6)

Output Voltage Load

ΔV

OUT

/ΔI

OUT

Regulation (Notes 5, 6)

GND

DISABLED

OUT(PK)

Ground Pin Current In Normal Operation Mode

Ground Pin Current

Peak Output Current

Short Circuit Current

Enable Input (LP38502 Only)

IH(EN)

IL(EN)

d(off)

d(on)

Enable Logic High

Enable Logic Low

Turn-off delay

Turn-on delay

Enable Pin High Current

Enable Pin Low Current

= 10 mA, CIN = 10 µF, C

OUT

2.7V ≤ VIN ≤ 5.5V 10 mA ≤ I

OUT

≤ 1.5A

2.7V ≤ VIN ≤ 5.5V 10 mA ≤ I

OUT

≤ 1.5A

2.7V ≤ VIN ≤ 5.5V

= 1.5A

OUT

2.7V ≤ VIN ≤ 5.5V

10 mA ≤ I

VEN < V

≥ V

OUT

= 0V

OUT

= ON

OUT

= OFF

OUT

IL(EN)

OUT(NOM)

≤ 1.5A

Time from VEN < V OFF I

= 1.5A

LOAD

Time from VEN >V ON I

= 1.5A

LOAD

VEN = V

VEN = 0V

- 5%

IL(EN)

IH(EN)

= 10 µF, VEN = VIN, V

OUT

0.584

0.575

0.596

0.587

to V

OUT

to V

OUT

= 1.8V. Limits in standard type

OUT

0.605

0.626

0.635

0.614

0.623

50 750 nA

220

—

0.04

0.05

0.18

0.33

—

0.025

275

375

—

3.5

4.5

0.125

3.6 A

2 3.7 A

1.4

— —

—

— —

0.65

0.1

—

0.6V to 5V

%/V

%/A

µA

µs

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Symbol Parameter Conditions Min Typ Max Units

AC Parameters

PSRR Ripple Rejection

n(l/f)

Output Noise Density

Output Noise Voltage

VIN = 3.0V, I f = 120Hz

VIN = 3.0V, I f = 1 kHz

f = 120Hz, C

BW = 100Hz – 100kHz C

= 10 µF CER

OUT

= 1.5A

OUT

= 1.5A

OUT

= 10 µF CER

OUT

—

1.0

100

—

µV/√Hz

µV (rms)

Thermal Characteristics

ΔT

Thermal Shutdown

Thermal Shutdown Hysteresis

Thermal Resistance

J-A

Junction to Ambient

Thermal Resistance Junction to Ambient

J-C

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 conditions, see the Electrical Characteristics.

Note 2: The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin.

Note 3: Operating junction temperature must be evaluated, and derated as needed, based on ambient temperature (TA), power dissipation (PD), maximum

allowable operating junction temperature (T

Note 4: Output voltage line regulation is defined as the change in output voltage from the nominal value due to change in the voltage at the input.

Note 5: Output voltage load regulation is defined as the change in output voltage from the nominal value due to change in the load current.

Note 6: The line and load regulation specification contains only the typical number. However, the limits for line and load regulation are included in the adjust

voltage tolerance specification.

Note 7: Dropout voltage is defined as the minimum input to output differential voltage at which the output drops 2% below the nominal value. For any output voltage less than 2.5V, the minimum VIN operating voltage is the limiting factor.

Note 8: The value of θJA for the TO-263 (TS) package and TO-263 THIN (TJ) package can range from approximately 30 to 60°C/W depending on the amount of PCB copper dedicated to heat transfer (See Application Information).

Note 9: θJA for the LLP-8 package was measured using the LP38502SD-ADJ evaluation board (See Application Information).

Thermal Resistance Junction to Case

J(MAX)

TJ rising

TJ falling from T

TO-263, TO-263 THIN(Note 8) 1 sq. in. copper

LLP-8 (Note 9)

TO-263, TO-263 THIN

LLP-8

), and package thermal resistance (θJA). See Application Information.

—

170

—

LP38500/2-ADJ, LP38500A/2A-ADJ

°C

°C/W

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