NSC LM2852YMXAX-3.3, LM2852 Datasheet

LM2852
2A 500/1500kHz Synchronous SIMPLE SWITCHER

®

Buck

Regulator

General Description

The LM2852 SIMPLE SWITCHER®synchronous buck regu­lator is a high frequency step-down switching voltage regu­lator capable of driving up to a 2A load with excellent line and
load regulation. The LM2852 can accept an input voltage
between 2.85V and 5.5V and deliver an output voltage that is
factory programmable from 0.8V to 3.3V in 100mV incre­ments. The LM2852 is available with a choice of two switch­ing frequencies - 500kHz (LM2852Y) or 1.5MHz (LM2852X).
It also features internal, type-three compensation to deliver a
low component count solution. The exposed-pad TSSOP-14
package enhances the thermal performance of the LM2852.

Features

n Input voltage range of 2.85 to 5.5V
n Factory EEPROM set output voltages from 0.8V to 3.3V

in 100mV increments

n Maximum load current of 2A
n Voltage Mode Control
n Internal type-three compensation
n Switching frequency of 500kHz or 1.5MHz
n Low standby current of 10µA
n Internal 60 mΩ MOSFET switches
n Standard voltage options 0.8/1.0/1.2/1.5/1.8/2.5/3.3 volts

Applications

n Low voltage point of load regulation
n Local solution for FPGA/DSP/ASIC core power
n Broadband networking and communications

infrastructure

n Portable computing

Typical Application Circuit

20127001

20127002

SIMPLE SWITCHER

®

SIMPLE SWITCHERreg; is a registered trademark of National Semiconductor Corporation

October 2006

LM2852 2A 500/1500kHz Synchronous SIMPLE SWITCHER

®

Buck Regulator

© 2006 National Semiconductor Corporation DS201270 www.national.com

Connection Diagram

TOP VIEW

20127003

MXA14A

ETSSOP-14

Pin Descriptions

AVIN (Pin 1): Chip bias input pin. This provides power to the

logic of the chip. Connect to the input voltage or a separate
rail.

EN (Pin 2): Enable. Connect this pin to ground to disable the
chip; connect to AVIN or leave floating to enable the chip;
enable is internally pulled up.

SGND (Pin 3): Signal ground.
SS (Pin 4): Soft-start pin. Connect this pin to a small capaci-

tor to control startup. The soft-start capacitance range is
restricted to values 1 nF to 50 nF.

NC (Pins 5, 12 and 13): No connect. These pins must be
tied to ground or left floating in the application.

PVIN (Pins 6, 7): Input supply pin. PVIN is connected to the
input voltage. This rail connects to the source of the internal
power PFET.

SW (Pins 8, 9): Switch pin. Connect to the output inductor.
PGND (Pins 10, 11): Power ground. Connect this to an

internal ground plane or other large ground plane.
SNS (Pin 14): Output voltage sense pin. Connect this pin to

the output voltage as close to the load as possible.

Exposed Pad: Connect to ground.

LM2852

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Ordering Information

Order Number Frequency

Voltage

Option Package Type

Package
Drawing Supplied As

LM2852YMXA-0.8

500kHz

0.8

TSSOP-14 exposed

pad

MXA14A

94 Units, Rail

LM2852YMXAX-0.8 2500 Units, Tape and Reel

LM2852YMXA-1.0 1.0 94 Units, Rail

LM2852YMXAX-1.0 2500 Units, Tape and Reel

LM2852YMXA-1.2 1.2 94 Units, Rail

LM2852YMXAX-1.2 2500 Units, Tape and Reel

LM2852YMXA-1.5 1.5 94 Units, Rail

LM2852YMXAX-1.5 2500 Units, Tape and Reel

LM2852YMXA-1.8 1.8 94 Units, Rail

LM2852YMXAX-1.8 2500 Units, Tape and Reel

LM2852YMXA-2.5 2.5 94 Units, Rail

LM2852YMXAX-2.5 2500 Units, Tape and Reel

LM2852YMXA-3.0 3.0 94 Units, Rail

LM2852YMXAX-3.0 2500 Units, Tape and Reel

LM2852YMXA-3.3 3.3 94 Units, Rail

LM2852YMXAX-3.3 2500 Units, Tape and Reel

LM2852XMXA-0.8

1500kHz

0.8 94 Units, Rail

LM2852XMXAX-0.8 2500 Units, Tape and Reel

LM2852XMXA-1.0 1.0 94 Units, Rail

LM2852XMXAX-1.0 2500 Units, Tape and Reel

LM2852XMXA-1.2 1.2 94 Units, Rail

LM2852XMXAX-1.2 2500 Units, Tape and Reel

LM2852XMXA-1.5 1.5 94 Units, Rail

LM2852XMXAX-1.5 2500 Units, Tape and Reel

LM2852XMXA-1.8 1.8 94 Units, Rail

LM2852XMXAX-1.8 2500 Units, Tape and Reel

LM2852XMXA-2.5 2.5 94 Units, Rail

LM2852XMXAX-2.5 2500 Units, Tape and Reel

LM2852XMXA-3.0 3.0 94 Units, Rail

LM2852XMXAX-3.0 2500 Units, Tape and Reel

LM2852XMXA-3.3 3.3 94 Units, Rail

LM2852XMXAX-3.3 2500 Units, Tape and Reel

Note: Contact factory for other voltage options.

LM2852

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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.

PVIN, AVIN, EN, SNS −0.3V to 6.5V

ESD Susceptibility (Note 2) 2kV

Power Dissipation Internally Limited

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

Maximum Junction Temp. 150˚C

14-Pin Exposed Pad TSSOP
Package

Infrared (15 sec)
Vapor Phase (60 sec)

Soldering (10 sec)

220˚C
215˚C
260˚C

Operating Ratings

PVIN to GND 1.5V to 5.5V

AVIN to GND 2.85V to 5.5V

Junction Temperature −40˚C to +125˚C

θ

JA

38˚C/W

Electrical Characteristics AVIN = PVIN = 5V unless otherwise indicated under the Conditions column.

Limits in standard type are for T

J

= 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 T

J

= 25˚C, and are provided for reference purposes only.

Symbol Parameter Conditions Min Typ Max Units

SYSTEM PARAMETERS

V

OUT

Voltage Tolerance3V

OUT

= 0.8V option 0.782 0.818 V

V

OUT

= 1.0V option 0.9775 1.0225

V

OUT

= 1.2V option 1.1730 1.2270

V

OUT

= 1.5V option 1.4663 1.5337

V

OUT

= 1.8V option 1.7595 1.8405

V

OUT

= 2.5V option 2.4437 2.5563

V

OUT

= 3.0V option 2.9325 3.0675

V

OUT

= 3.3V option 3.2257 3.3743

∆V

OUT

/∆AVIN Line Regulation3V

OUT

= 0.8V, 1.0V, 1.2V, 1.5V, 1.8V or

2.5V

2.85V ≤ AVIN ≤ 5.5V

0.2 0.6 %

V

OUT

= 3.3V

3.5V ≤ AVIN ≤ 5.5V

0.2 0.6 %

∆V

OUT

/∆I

O

Load Regulation Normal operation 8 mV/A

V

ON

UVLO Threshold

(AVIN)

Rising 2.47 2.85 V

Falling Hysteresis 85 150 210 mV

r

DSON-P

PFET On

Resistance

Isw=2A 75 140 mΩ

r

DSON-N

NFET On

Resistance

Isw=2A 55 120 mΩ

R

SS

Soft-start

resistance

400 kΩ

I

CL

Peak Current Limit

Threshold

LM2852X 2.75 4 4.95 A

LM2852Y 2.25 3 3.65

I

Q

Operating Current Non-switching 0.85 2 mA

I

SD

Shutdown

Quiescent Current

EN=0V 10 25 µA

R

SNS

Sense pin
resistance

400 kΩ

PWM

f

osc

LM2852X 1500kHz option. 1050 1500 1825 kHz

LM2852Y 500kHz option. 325 500 625 kHz

LM2852

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Electrical Characteristics AVIN = PVIN = 5V unless otherwise indicated under the Conditions column.

Limits in standard type are for T

J

= 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 T

J

= 25˚C, and are provided for reference purposes only. (Continued)

Symbol Parameter Conditions Min Typ Max Units

D

range

Duty Cycle Range 0 100 %

ENABLE CONTROL

4

V

IH

EN Pin Minimum

High Input

75 %of

AVIN

V

IL

EN Pin Maximum

Low Input

25 %of

AVIN

I

EN

EN Pin Pullup

Current

EN = 0V 1.2 µA

THERMAL CONTROLS

T

SD

TJfor Thermal

Shutdown

165 ˚C

T

SD-HYS

Hysteresis for

Thermal Shutdown

10 ˚C

Note 1: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating Range indicates conditions for which the device is
intended to be functional, but does not guarantee specfic performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.

Note 2: Human body model: 1.5kΩ in series with 100pF. SW and PVIN pins are derated to 1.5kV

Note 3: V

OUT

measured in a non-switching, closed-loop configuration at the SNS pin.

Note 4: The enable pin is internally pulled up, so the LM2852 is automatically enabled unless an external enable voltage is applied.

LM2852

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