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LT3480 Datasheet, PDF (1/24 Pages) Linear Technology – 36V, 2A, 2.4MHz Step-Down Switching Regulator with 70μA Quiescent Current | |||
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LT3480
FEATURES
36V, 2A, 2.4MHz Step-Down
Switching Regulator with
70µA Quiescent Current
DESCRIPTION
n Wide Input Range:
Operation from 3.6V to 36V
Over-Voltage Lockout Protects Circuits
through 60V Transients
n 2A Maximum Output Current
n Low Ripple Burst Mode® Operation
70μA IQ at 12VIN to 3.3VOUT
Output Ripple < 15mV
n Adjustable Switching Frequency: 200kHz to 2.4MHz
n Low Shutdown Current: IQ < 1μA
n Integrated Boost Diode
n Synchronizable Between 250kHz to 2MHz
n Power Good Flag
n Saturating Switch Design: 0.25 On-Resistance
n 0.790V Feedback Reference Voltage
n Output Voltage: 0.79V to 20V
n Soft-Start Capability
n Small 10-Pin Thermally Enhanced MSOP and
(3mm à 3mm) DFN Packages
The LT®3480 is an adjustable frequency (200kHz to
2.4MHz) monolithic buck switching regulator that ac-
cepts input voltages up to 36V (60V maximum). A high
efï¬ciency 0.25 switch is included on the die along with
a boost Schottky diode and the necessary oscillator, con-
trol, and logic circuitry. Current mode topology is used
for fast transient response and good loop stability. Low
ripple Burst Mode operation maintains high efï¬ciency at
low output currents while keeping output ripple below
15mV in a typical application. In addition, the LT3480 can
further enhance low output current efï¬ciency by draw-
ing bias current from the output when VOUT is above 3V.
Shutdown reduces input supply current to less than 1μA
while a resistor and capacitor on the RUN/SS pin provide a
controlled output voltage ramp (soft-start). A power good
ï¬ag signals when VOUT reaches 86% of the programmed
output voltage. The LT3480 is available in 10-Pin MSOP
and 3mm à 3mm DFN packages with exposed pads for
low thermal resistance.
APPLICATIONS
n Automotive Battery Regulation
n Power for Portable Products
n Distributed Supply Regulation
n Industrial Supplies
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
3.3V Step-Down Converter
VIN
4.5V TO 36V
TRANSIENT
TO 60V
OFF ON
14k
4.7μF
470pF
40.2k
VIN
RUN/SS
BD
BOOST
VC
LT3480
SW
RT
PG
SYNC
GND
FB
VOUT
3.3V
2A
0.47μF 4.7μH
316k
100k
22μF
3480 TA01
Efï¬ciency
100
VOUT = 5V
90
80
VOUT = 3.3V
70
60
VIN = 12V
L = 5.6μH
50
F = 800 kHz
0 0.5
1.0
1.5
2
LOAD CURRENT (A)
3480 TA01b
3480fb
1
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