7.4A

+

-

COMP

CONTROL

LOGIC

CURRENT

LIMIT

OVERVOLTAGE

UNDERVOLTAGE

ERROR AMP

PWM COMPARATOR

SS/TRK

PGOOD

+

-

+2.7V

REGULATOR

PVIN

PVIN

THERMAL

PROTECTION

PGND

SW

AVIN

CURRENT SENSE

VCC

1.18V

UVLO

2.7V

AGND

OSCILLATOR

+

752 mV

864 mV

PG-L

PG-L

2.7V

5 PA

800 mV

+

-

+

DISCHARGE

DISCHARGE

SLOPE COMP

DIODE

EMULATION

+

-

VREF

+

-

FB

EN

+

-

+

-

(50 Ps)

+

-

+

-

PVIN

LM20125

www.ti.com

SNVS525E – OCTOBER 2007 – REVISED MARCH 2013

BLOCK DIAGRAM

OPERATION DESCRIPTION

GENERAL

The LM20125 switching regulator features all of the functions necessary to implement an efficient low voltage

buck regulator using a minimum number of external components. This easy to use regulator features two

integrated switches and is capable of supplying up to 5A of continuous output current. The regulator utilizes peak

current mode control with nonlinear slope compensation to optimize stability and transient response over the

entire output voltage range. Peak current mode control also provides inherent line feed-forward, cycle-by-cycle

current limiting and easy loop compensation. The fixed 500 kHz operating frequency minimizes the inductor size

while still achieving efficiencies up to 96%. The precision internal voltage reference allows the output to be set as

low as 0.8V. Fault protection features include: current limiting, thermal shutdown, over voltage protection, and

shutdown capability. The device is available in the HTSSOP 16-pin package featuring an exposed pad to aid

thermal dissipation. The LM20125 can be used in numerous applications to efficiently step-down from a 5V or

3.3V bus. The typical application circuit for the LM20125 is shown in Figure 25 in the design guide.

Copyright © 2007–2013, Texas Instruments Incorporated

Submit Documentation Feedback

9

Product Folder Links: LM20125