ltm8027 Linear Technology Corporation, ltm8027 Datasheet - Page 10

• Manufacturer Part Number: ltm8027
• Description: 60v, 4a Dc/dc ?module Regulator
• Manufacturer: Linear Technology Corporation

LTM8027
BLOCK DIAGRAM
OPERATION
The LTM8027 is a standalone nonisolated step-down
switching DC/DC power supply with an input voltage
range of 4.5V to 60V that can deliver up to 4A of output
current. This module provides a precisely regulated output
voltage up to 24V, programmable via one external resistor.
Given that the LTM8027 is a step-down converter, make
sure that the input voltage is high enough to support the
desired output voltage and load current. A simplifi ed block
diagram is given above. The LTM8027 contains a current
mode controller, power switching element, power induc-
tor, power MOSFETs and a modest amount of input and
output capacitance.
10
V
RUN
SS
SYNC
IN
CONTROLLER
CURRENT
MODE
GND
R
T
V
IN
REGULATOR
INTERNAL
LINEAR
The LTM8027 is a fi xed frequency PWM regulator. The
switching frequency is set by simply connecting the ap-
propriate resistor from the RT pin to GND.
A linear regulator provides internal power (shown as
INTV
bias regulator normally draws power from the V
if the BIAS1and BIAS2 pins are connected to an external
voltage higher than 8.5V, bias power will be drawn from
the external source (typically the regulated output voltage).
This improves effi ciency. The RUN pin is used to enable
or place the LTM8027 in shutdown, disconnecting the
output and reducing the input current to less than 10μA.
CC
on the Block Diagram) to the control circuitry. The
INTV
6.8μH
4.7pF
CC
ADJ
499k
CONNECTION
INTERNAL
TO V
2.2μF
OUT
BIAS1
BIAS2
V
AUX
OUT
8027 BD
IN
pin, but
8027f