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LM2852 2A 500/1500kHz Synchronous SIMPLE SWITCHER
®
Buck Regulator
October 2006
LM2852
2A 500/1500kHz Synchronous SIMPLE SWITCHER
®
Buck
Regulator
General Description
The LM2852 SIMPLE SWITCHER
®
synchronous buck regu-
lator is a high frequency step-down switching voltage regu-
lator 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 incre-
ments. The LM2852 is available with a choice of two switch-
ing 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
© 2006 National Semiconductor Corporation
DS201270
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LM2852
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.
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2
LM2852
Ordering Information
Order Number
LM2852YMXA-0.8
LM2852YMXAX-0.8
LM2852YMXA-1.0
LM2852YMXAX-1.0
LM2852YMXA-1.2
LM2852YMXAX-1.2
LM2852YMXA-1.5
LM2852YMXAX-1.5
LM2852YMXA-1.8
LM2852YMXAX-1.8
LM2852YMXA-2.5
LM2852YMXAX-2.5
LM2852YMXA-3.0
LM2852YMXAX-3.0
LM2852YMXA-3.3
LM2852YMXAX-3.3
LM2852XMXA-0.8
LM2852XMXAX-0.8
LM2852XMXA-1.0
LM2852XMXAX-1.0
LM2852XMXA-1.2
LM2852XMXAX-1.2
LM2852XMXA-1.5
LM2852XMXAX-1.5
LM2852XMXA-1.8
LM2852XMXAX-1.8
LM2852XMXA-2.5
LM2852XMXAX-2.5
LM2852XMXA-3.0
LM2852XMXAX-3.0
LM2852XMXA-3.3
LM2852XMXAX-3.3
Note:
Contact factory for other voltage options.
Frequency
Voltage
Option
0.8
1.0
1.2
1.5
Package Type
Package
Drawing
Supplied As
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
500kHz
1.8
2.5
3.0
3.3
0.8
1.0
1.2
1.5
TSSOP-14 exposed
pad
MXA14A
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
94 Units, Rail
2500 Units, Tape and Reel
1500kHz
1.8
2.5
3.0
3.3
3
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LM2852
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
ESD Susceptibility (Note 2)
Power Dissipation
Storage Temperature Range
Maximum Junction Temp.
14-Pin Exposed Pad TSSOP
Package
Infrared (15 sec)
Vapor Phase (60 sec)
Soldering (10 sec)
−0.3V to 6.5V
2kV
Internally Limited
−65˚C to +150˚C
150˚C
220˚C
215˚C
260˚C
Operating Ratings
PVIN to GND
AVIN to GND
Junction Temperature
θ
JA
1.5V to 5.5V
2.85V to 5.5V
−40˚C to +125˚C
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 (T
J
) range of -40˚C
to +125˚C. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values repre-
sent the most likely parametric norm at T
J
= 25˚C, and are provided for reference purposes only.
Symbol
V
OUT
Parameter
Conditions
Min
0.782
0.9775
1.1730
1.4663
1.7595
2.4437
2.9325
3.2257
0.2
Typ
Max
0.818
1.0225
1.2270
1.5337
1.8405
2.5563
3.0675
3.3743
0.6
%
Units
V
SYSTEM PARAMETERS
Voltage Tolerance
3
V
OUT
= 0.8V option
V
OUT
= 1.0V option
V
OUT
= 1.2V option
V
OUT
= 1.5V option
V
OUT
= 1.8V option
V
OUT
= 2.5V option
V
OUT
= 3.0V option
V
OUT
= 3.3V option
∆V
OUT
/∆AVIN
Line Regulation
3
V
OUT
= 0.8V, 1.0V, 1.2V, 1.5V, 1.8V or
2.5V
2.85V
≤
AVIN
≤
5.5V
V
OUT
= 3.3V
3.5V
≤
AVIN
≤
5.5V
∆V
OUT
/∆I
O
V
ON
r
DSON-P
r
DSON-N
R
SS
I
CL
I
Q
I
SD
R
SNS
PWM
f
osc
LM2852X
LM2852Y
1500kHz option.
500kHz option.
1050
325
1500
500
1825
625
kHz
kHz
Load Regulation
UVLO Threshold
(AVIN)
PFET On
Resistance
NFET On
Resistance
Soft-start
resistance
Peak Current Limit LM2852X
Threshold
LM2852Y
Operating Current Non-switching
Shutdown
EN = 0V
Quiescent Current
Sense pin
resistance
2.75
2.25
Normal operation
Rising
Falling Hysteresis
Isw = 2A
Isw = 2A
85
0.2
8
2.47
150
75
55
400
4
3
0.85
10
400
0.6
%
mV/A
2.85
210
140
120
V
mV
mΩ
mΩ
kΩ
4.95
3.65
2
25
A
mA
µA
kΩ
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4
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