ltm4608a Linear Technology Corporation, ltm4608a Datasheet - Page 9

• Manufacturer Part Number: ltm4608a
• Description: Low Vin, 8a Dc/dc ?module With Tracking, Margining, And Frequency Synchronization
• Manufacturer: Linear Technology Corporation

Table 1. Decoupling Requirements. T
SYMBOL
C
C
OPERATION
SIMPLIFIED BLOCK DIAGRAM
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 2.4V 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
IN
OUT
PHMODE
CLKOUT
PLLLPF
PGOOD
TRACK
MODE
CLKIN
SGND
BSEL
MGN
I
SV
RUN
THM
I
TH
IN
PARAMETER
External Input Capacitor Requirement
(V
External Output Capacitor Requirement
(V
IN
IN
INTERNAL
COMP
= 2.4V to 5.5V, V
= 2.4V to 5.5V, V
INTERNAL
FILTER
A
OUT
OUT
= 25°C, Block Diagram Confi guration.
= 1.5V)
= 1.5V)
Figure 1. Simplifi ed LTM4608A Block Diagram
INTERNAL
CONTROL
POWER
FILTER
CONDITIONS
I
I
OUT
OUT
= 8A
= 8A
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.
With current mode control and internal feedback loop
compensation, the LTM4608A module has suffi cient
stability margins and good transient performance with
a wide range of output capacitors, even with all ceramic
output capacitors.
M1
M2
L
10μF
22μF
10μF
10k
10μF
MIN
22pF
10
V
SW
V
GND
FB
4608A BD
IN
OUT
+
LTM4608A
TYP
100
R
6.65k
FB
C
IN
C
OUT
V
2.4 TO 5.5V
V
1.5V
IN
OUT
MAX
UNITS
4608af
9
μF
μF