herunterladen
2.7V - 4.2V
LM3224
L
4.7 PH
CC
1 nF
D
RC
20k
CIN
22 PF
COUT
10 PF
6.98k
SHDN
3
V
IN
6
SW
5
FSLCT
7
FB
2
GND
4
V
C
1
SS
8
20.5k
5V
CC1
open
CSS
open
User's Guide
SNVA121A–January 2006–Revised April 2013
AN-1394 LM3224 Evaluation Board
1 Introduction
The LM3224 is a step-up DC/DC converter with a 0.15 Ω (typ.), 2.45A (typ.) internal switch and pin
selectable operating frequency. The LM3224 can be operated at switching frequencies of 615 kHz and
1.25 MHz allowing for easy filtering and low noise. An external compensation pin gives you flexibility in
setting frequency compensation, which makes possible the use of small, low ESR ceramic capacitors at
the output. An external soft-start pin allows you to control the amount of inrush current during start up.
The LM3224 evaluation board is set up for a 5 V output from an input voltage from 2.7 V to 4.2 V, or the
equivalent range of a Li-Ion battery. Included on the board are two jumpers: one to select the switching
frequency and one to select if the device is on or off. Both can also be controlled externally by removing
the jumper. The regulator is capable of supplying up to at least 650 mA of load current down to the
minimum of 2.7 V input at 1.25 MHz operation.
2 Schematic and Layout
Figure 1. Schematic
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1
SNVA121A–January 2006–Revised April 2013 AN-1394 LM3224 Evaluation Board
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- ・ Blockdiagramm on Seite 1
- ・ Anwendungsbereich on Seite 3
