LM3495_14 Datasheet, PDF (1/35 Pages) Texas Instruments – Emulated Peak Current Mode Buck Controller for Low Output Voltage

LM3495
www.ti.com
SNVS410E – FEBRUARY 2006 – REVISED NOVEMBER 2007
LM3495 Emulated Peak Current Mode Buck Controller for Low Output Voltage
Check for Samples: LM3495
FEATURES
1
•2 Input voltage from 2.9V to 18V
• Output voltage adjustable from 0.6V to 5.5V
• Feedback Accuracy: ±1%
• Low-side Sensing, Programmable Current
Limit without sense resistor
• Input Under Voltage Lockout
• Hiccup mode current limit protection
eliminates thermal runaway during fault
conditions
• Internal soft start with tracking capability
• 200 kHz to 1.5 MHz Switching frequency,
Synchronizable
• On-chip gate drivers
• Soft output discharge during shutdown
• Startup into output pre-bias
• Operation from a single input rail
• Adaptive Duty Cycle Limit
• TSSOP-16 package
APPLICATIONS
• Wide input voltage buck converters with low
voltage, high accuracy outputs
• Core logic regulators
• High-efficiency buck regulation
DESCRIPTION
The LM3495 is a PWM buck regulator which implements a unique emulated peak current mode control. This
control method eliminates the switching noise which typically limits current mode operation at extremely short
duty cycles and high operating frequency. The switching frequency is programmable between 200 kHz and 1.5
MHz, and can also be synchronized to an external clock. The LM3495 is also very fault tolerant with both switch
node short, hiccup mode, and adaptive duty cycle limit protection. A 0.6V 1% reference and glitch free pre-biased
start-up ensure the most demanding digital loads operate reliably. Internal soft start and the ability to track the
output of another supply make the LM3495 versatile and efficient.
Typical Application
C_F
C_DD
D1
V_IN
C_SYNC
R_FRQ
VLIN5
R_C
C_C
R_FB1
R_FB2
FPWM ^VIN
FREQ/SYNC
VLIN5 _BOOST
C_B
HG
SW/CSH
TRACK
LM3495 _ILIM
RILIM
LG
COMP/SD
CSL
FB
SNS
SGND ^PGND
C_INX
Q1
L1
Q2
C_IN
V_O
C_O
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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 © 2006–2007, Texas Instruments Incorporated