LTC3614_15 Datasheet, PDF (1/30 Pages) Linear Technology – 4A, 4MHz Monolithic Synchronous Step-Down DC/DC Converter

LTC3614
Features
n _{4A Output Current}
n _{2.25V to 5.5V Input Voltage Range}
n _{Low Output Ripple Burst Mode}^® _{Operation: IQ = 75µA}
n _{±1% Output Voltage Accuracy}
n _{Output Voltage Down to 0.6V}
n _{High Efficiency: Up to 95%}
n _{Low Dropout Operation: 100% Duty Cycle}
n _{Programmable Slew Rate on SW Node Reduces}
Noise and EMI
n _{Adjustable Switching Frequency: Up to 4MHz}
n _{Optional Active Voltage Positioning (AVP) with}
Internal Compensation
n _{Selectable Pulse-Skipping/Forced Continuous/Burst}
Mode Operation with Adjustable Burst Clamp
n _{Programmable Soft-Start}
n _{Inputs for Start-Up Tracking or External Reference}
n _{DDR Memory Mode, IOUT = ±3A}
n _{Available in a 24-Pin 3mm × 5mm QFN}
Thermally Enhanced Package
Applications
n _{Point-of-Load Supplies}
n _{Distributed Power Supplies}
n _{Portable Computer Systems}
n _{DDR Memory Termination}
n _{Handheld Devices}
4A, 4MHz Monolithic
Synchronous Step-Down
DC/DC Converter
Description
The LTC^®3614 is a low quiescent current monolithic syn-
chronous buck regulator using a current mode, constant
frequency architecture. The no-load DC supply current
in sleep mode is only 75µA while maintaining the output
voltage (Burst Mode operation) at no load, dropping to
zero current in shutdown. The 2.25V to 5.5V input supply
voltage range makes the LTC3614 ideally suited for single
Li-Ion as well as fixed low voltage input applications. 100%
duty cycle capability provides low dropout operation,
extending the operating time in battery-powered systems.
The operating frequency is externally programmable up to
4MHz, allowing the use of small surface mount inductors.
For switching-noise-sensitive applications, the LTC3614
can be synchronized to an external clock at up to 4MHz.
Forced continuous mode operation in the LTC3614 reduces
noise and RF interference. Adjustable compensation allows
the transient response to be optimized over a wide range
of loads and output capacitors.
The internal synchronous switch increases efficiency and
eliminates the need for an external catch diode, saving
external components and board space. The LTC3614
is offered in a leadless 24-pin 3mm × 5mm thermally
enhanced QFN package.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6580258, 5481178, 5994885, 6304066, 6498466, 6611131.
Typical Application
V_IN
2.7V TO 5.5V
SV_IN
PV_IN
RUN
SRLIM/DDR
TRACK/SS
RT/SYNC
LTC3614 SW
PGOOD
SGND
ITH
PGND
MODE
V_FB
210k
10µF
×4
330nH
665k
V_OUT
2.5V
4A
47µF
×2
3614 TA01a
Efficiency and Power Loss
vs Load Current
100
90
80
1
70
60
0.1
50
40
0.01
30
20
10
0 ^{VOUT = 2.5V}
1
10
V_IN = 2.8V ⁰
V_IN = 3.3V
V_IN = 5V
100
1000 10000
OUTPUT CURRENT (mA)
3614 TA01b
For more information www.linear.com/LTC3614
3614fc
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