LM3475_14 Datasheet, PDF (1/21 Pages) Texas Instruments – Hysteretic PFET Buck Controller

LM3475
www.ti.com
SNVS239A – OCTOBER 2004 – REVISED JANUARY 2005
LM3475 Hysteretic PFET Buck Controller
Check for Samples: LM3475
FEATURES
1
•2 Easy to Use Control Methodology
• 0.8V to V_IN Adjustable Output Range
• High Efficiency (90% Typical)
• ±0.9% (±1.5% Over Temp) Feedback Voltage
• 100% Duty Cycle Capable
• Maximum Operating Frequency up to 2MHz
• Internal Soft-Start
• Enable Pin
• SOT-23-5 Package
DESCRIPTION
The LM3475 is a hysteretic P-FET buck controller
designed to support a wide range of high efficiency
applications in a very small SOT-23-5 package. The
hysteretic control scheme has several advantages,
including simple system design with no external
compensation, stable operation with a wide range of
components, and extremely fast transient response.
Hysteretic control also provides high efficiency
operation, even at light loads. The PFET architecture
allows for low component count as well as 100% duty
cycle and ultra-low dropout operation.
APPLICATIONS
• TFT Monitor
• Auto PC
• Vehicle Security
• Navigation Systems
• Notebook Standby Supply
• Battery Powered Portable Applications
• Distributed Power Systems
Typical Application Circuit
V_IN = 5V
C_IN
10 PF
Q1
Si2343
5
D1
PGATE
4
2
V_IN
GND
LM3475
L1
10 PH
C_OUT
100 PF
C_FF
1 nF
V_OUT = 2.5V/2A
R_FB1
2.15k
3
EN
1
FB
R_FB2
1k
1
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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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