Datasheet

5.2A
+
-
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)
+
-
+
-
SYNC
PVIN
LM20133, LM20133Q
SNVS526F –OCTOBER 2007–REVISED MARCH 2013 www.ti.com
BLOCK DIAGRAM
OPERATION DESCRIPTION
GENERAL
The LM20133 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 3A 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 internal oscillator can synchronize up to 1.5 MHz minimizing
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 LM20133 can be used in numerous applications to efficiently step-
down from a 5V or 3.3V bus. The typical application circuit for the LM20133 is shown in Figure 30.
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