Datasheet

LTM4608A
9
4608afd
siMpliFieD block DiagraM
INTERNAL
FILTER
POWER
CONTROL
INTERNAL
COMP
INTERNAL
FILTER
SV
IN
TRACK
MGN
BSEL
PGOOD
MODE
RUN
CLKIN
CLKOUT
PHMODE
PLLLPF
SGND
I
TH
I
THM
M1
22µF
C
OUT
10µF 10µF 10µF
C
IN
V
IN
2.7 TO 5.5V
V
OUT
1.5V
V
OUT
V
IN
SW
GND
FB
22pF
10k
R
FB
6.65k
4608A BD
0.22µH
M2
+
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
C
IN
External Input Capacitor Requirement
(V
IN
= 2.7V to 5.5V, V
OUT
= 1.5V)
I
OUT
= 8A 10 µF
C
OUT
External Output Capacitor Requirement
(V
IN
= 2.7V to 5.5V, V
OUT
= 1.5V)
I
OUT
= 8A 100 µF
Table 1. Decoupling Requirements. T
A
= 25°C, Block Diagram Configuration
Figure 1. Simplified LTM4608A Block Diagram
operaTion
The LTM4608A is a standalone nonisolated switch mode
DC/DC power supply. It can deliver up to 8A of DC output
current with few external input and output capacitors.
This module provides precisely regulated output voltage
programmable via one external resistor from 0.6V DC to
5.0V DC over a 2.7V to 5.5V input voltage. The typical
application schematic is shown in Figure 18.
The LTM4608A has an integrated constant frequency cur-
rent mode regulator and built-in power MOSFET devices
with fast switching speed. The typical switching frequency
is 1.5MHz. For switching noise sensitive applications, it
can be externally synchronized from 0.75MHz to 2.25MHz.
Even spread spectrum switching can be implemented in
the design to reduce noise.