lm20133mhx National Semiconductor Corporation, lm20133mhx Datasheet - Page 2

• Manufacturer Part Number: lm20133mhx
• Description: 3a, Powerwise Synchronous Buck Regulator With Input Synchronization
• Manufacturer: National Semiconductor Corporation

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Connection Diagram
Ordering Information
Pin Descriptions
Order Number
LM20133MHE
LM20133MHX
10,11
Pin #
LM20133MH
6,7
8,9
EP
12
13
14
15
16
1
2
3
4
5
Exposed Pad
PGOOD
SS/TRK
COMP
PGND
AGND
Name
SYNC
PVIN
AVIN
VCC
SW
NC
EN
FB
Package Type
eTSSOP-16
Soft-Start or Tracking control input. An internal 5 µA current source charges an external capacitor to
set the Soft-Start ramp rate. If driven by a external source less than 800 mV, this pin overrides the
internal reference that sets the output voltage. If left open, an internal 1ms Soft-Start ramp is activated.
Feedback input to the error amplifier from the regulated output. This pin is connected to the inverting
input of the internal transconductance error amplifier. An 800mV reference connected to the non-
inverting input of the error amplifier sets the closed loop regulation voltage at the FB pin.
Power good output signal. Open drain output indicating the output voltage is regulating within
tolerance. A pull-up resistor of 10 to 100 kΩ is recommend for most applications.
External compensation pin. Connect a resistor and capacitor to this pin to compensate the device.
These pins must be connected to GND to ensure proper operation.
Input voltage to the power switches inside the device. These pins should be connected together at the
device. A low ESR capacitor should be placed near these pins to stabilize the input voltage.
Switch pin. The PWM output of the internal power switches.
Power ground pin for the internal power switches.
Precision enable input for the device. An external voltage divider can be used to set the device turn-
on threshold. If not used the EN pin should be connected to PVIN.
Internal 2.7V sub-regulator. This pin should be bypassed with a 1 µF ceramic capacitor.
Analog input supply that generates the internal bias. Must be connected to VIN through a low pass
RC filter.
Quiet analog ground for the internal bias circuitry.
Frequency synchronization pin. An external clock connected to this pin will set the switching frequency.
If left open the device will switch at approximately 410 kHz.
Exposed metal pad on the underside of the package with a weak electrical connection to ground. It is
recommended to connect this pad to the PC board ground plane in order to improve heat dissipation.
NSC Package Drawing
eTSSOP-16 Package
MXA16A
Top View
2
Description
Package Marking
30030302
20133MH
2500 Units of Tape and Reel
250 Units of Tape and Reel
92 Units of Rail
Supplied As