LM3224 Datasheet, PDF (1/26 Pages) National Semiconductor (TI) – 615kHz/1.25MHz Step-up PWM DC/DC Converter

LM3224
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SNVS277B – DECEMBER 2004 – REVISED SEPTEMBER 2005
LM3224 615kHz/1.25MHz Step-up PWM DC/DC Converter
Check for Samples: LM3224
FEATURES
1
•2 Operating voltage range of 2.7V to 7V
• 615kHz/1.25MHz pin selectable frequency
operation
• Over temperature protection
• Optional soft-start function
• 8-Lead MSOP package
APPLICATIONS
• TFT Bias Supplies
• Handheld Devices
• Portable Applications
• GSM/CDMA Phones
• Digital Cameras
• White LED Flash/Torch Applications
DESCRIPTION
The LM3224 is a step-up DC/DC converter with a 0.15Ω (typ.), 2.45A (typ.) internal switch and pin selectable
operating frequency. With the ability to convert 3.3V to multiple outputs of 8V, -8V, and 23V, the LM3224 is an
ideal part for biasing TFT displays. With the high current switch it is also ideal for driving high current white LEDs
for flash applications. The LM3224 can be operated at switching frequencies of 615kHz and 1.25MHz allowing
for easy filtering and low noise. An external compensation pin gives the user 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 the user to control the amount of inrush current during start up. The LM3224 is available in a
low profile 8-lead MSOP package.
Typical Application Circuit
V_IN
L
D
Battery or
Power Source
5
6 _VIN
SW
7
FSLCT
3 _{SHDN LM3224}
2
8
FB
C_IN
SS _VC
GND
1
4
Optional
R_C
C_SS
C_C
R_FB1
V_OUT
R_FB2
C_OUT
1
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004–2005, Texas Instruments Incorporated