Техническая Спецификация для Texas Instruments SIMPLE SWITCHER® 42V, 0.5A Step-Down Switching Regulator LM25575BLDT/NOPB LM25575BLDT/NOPB
Модели
LM25575BLDT/NOPB
Rfb1
BST
SW
COMP
FB
SS
RAMP
RT
VCC
VIN
OUT
IS
PGND
LM(2)5575
INPUT
OUTPUT
SD
SYNC
Ccomp
C
RAMP
C3
Cbyp
Cboot
Cin
Cout
Css
Rt
1
2
3
4
5
6
7
8
AGND
9
10
12
13
14
15
16
PRE
Rcomp
11
C4
R3
C7
C5
R4
C6
C8
D1
L1
R1
Rfb2
R2
C1
C2
C9
Introduction
1
Introduction
The LM5575 and LM25575 switching regulators feature all of the functions necessary to implement an
efficient high voltage buck regulator using a minimum of external components. These easy to use
regulators include either a 42V (LM25575) or a 75V (LM5575) N-Channel buck switch with an output
current capability of 1.5 Amps. The operating frequency is programmable from 50kHz up to 1MHz.
Protection features include: current limit, thermal shutdown and remote shutdown capability. The device is
available in a power enhanced TSSOP-16 package featuring an exposed die attach pad to aid thermal
dissipation.
efficient high voltage buck regulator using a minimum of external components. These easy to use
regulators include either a 42V (LM25575) or a 75V (LM5575) N-Channel buck switch with an output
current capability of 1.5 Amps. The operating frequency is programmable from 50kHz up to 1MHz.
Protection features include: current limit, thermal shutdown and remote shutdown capability. The device is
available in a power enhanced TSSOP-16 package featuring an exposed die attach pad to aid thermal
dissipation.
This step-by-step guide provides an easy to use process to quickly select the external components
necessary to complete a design. More detailed information including theory of operation, design trade-offs
and additional application guidance is available in the device datasheet. Shown below in
necessary to complete a design. More detailed information including theory of operation, design trade-offs
and additional application guidance is available in the device datasheet. Shown below in
is a
complete schematic for a 1.5 Amp step-down DC-DC converter. Several external component values can
be standardized for most applications. The input voltage range, output voltage and desired operating
frequency dictate the remaining component values.
be standardized for most applications. The input voltage range, output voltage and desired operating
frequency dictate the remaining component values.
An Excel based spreadsheet derived from the guide is available on
Figure 1. Application Schematic
2
Quick Guide Design Worksheet
Step 1. List the basic requirements:
Output Current: 0 to 1.5 Amp
Output Voltage:
V [1]
Input Voltage Min Spec:
V [2]
Input Voltage Max Spec:
V [3]
Step 2. If the Input Voltage Max Spec [3] is less than 42V use the LM25575. If the Input Voltage Max
Spec [3] is greater than 42V but less than 75V use the LM5575. Both devices require the Input Voltage
Min Spec [2] to be greater than 6V.
Spec [3] is greater than 42V but less than 75V use the LM5575. Both devices require the Input Voltage
Min Spec [2] to be greater than 6V.
Selected Regulator:
[4]
2
AN-1571 Quick Start Guide for a 1.5 Amp Buck Regulator Using the LM5575
SNVA211B – January 2007 – Revised April 2013
and LM25575
Copyright © 2007–2013, Texas Instruments Incorporated