Datasheet
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
g
m
= 510 Pmho
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