LT3692_15 Datasheet, PDF (1/36 Pages) Linear Technology – Monolithic Dual Tracking 3.5A Step-Down Switching Regulator

Features
n _{Wide Input Range:}
– Operation from 3V to 36V
– OVLO Protects Circuit Through 60V Transients
n _{Independent Supply, Shutdown, Soft-Start,}
Programmable Current Limit and Programmable
Power Good for Each 3.5A Regulator
n _{Die Temperature Monitor}
n _{Adjustable/Synchronizable Fixed Frequency}
Operation from 250kHz to 2.25MHz with
Synchronized Clock Output
n _{Independent Synchronized Switching Frequencies}
Optimize Component Size
n _{Antiphase Switching}
n _{Outputs Can Be Paralleled}
n _{Flexible Output Voltage Tracking}
n _{Enhanced Short-Circuit Protection}
n _{Low Dropout: 95% Maximum Duty Cycle}
n _{5mm × 5mm QFN Package}
Applications
n _{Automotive Supplies}
n _{Distributed Supply Regulation}
LT3692
Monolithic Dual Tracking
3.5A Step-Down
Switching Regulator
Description
The LT^®3692 is a dual current mode PWM step-down
DC/DC converter with two internal 3.8A switches. Indepen-
dent input voltage, shutdown, feedback, soft-start, current
limit and comparator pins for each channel simplify com-
plex power supply tracking and sequencing requirements.
To optimize efficiency and component size, both convert-
ers have a programmable maximum current limit and are
synchronized to either a common external clock input,
or a resistor settable fixed 250kHz to 2.25MHz internal
oscillator. A frequency divider is provided for channel 1
to further optimize component size. At all frequencies, a
180° phase relationship between channels is maintained,
reducing voltage ripple and component size. A clock output
is available for synchronizing multiple regulators.
Minimum input to output voltage ratios are improved by
allowing the switch to stay on through multiple clock cycles
only switching off when the boost capacitor needs recharg-
ing. Independent channel operation can be programmed
using the SHDN pin. Disabling both converters reduces
the total quiescent to <10µA.
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
Typical Application
Independent Synchronized Switching Frequencies
Extend Full Frequency Input Range
Dual 1.8V/3.5A and 5V/3.5A Step-Down Converter
V_IN
6V TO 32V
V_OUT2
V_OUT1
1.8V 3.5A
500kHz/
250kHz
143k
7.15k
0.47µF
100µF
×2 8.06k
60.4k
60.4k
47pF
4.7µF
×2
V_IN1
SHDN1
BST1
V_IN2
SHDN2
BST2
SW1
SW2
6.8µH
IND1
IND2
LT3692
V_OUT1
V_OUT2
10k
FB1
FB2
CMPI1
CMPI2
CMPO1 CMPO2
SS2 SS1
SS2
ILIM2 ILIM1
ILIM2
DIV
CLKOUT
680pF
17.8k
V_C1
RT/SYNC
GND
13.0k
V_C2
T_J
0.1µF
6.8µH
42.2k _8.06k
1µF
100k
V_OUT2
5V 3.5A
47µF ^500kHz
PG2
CLOCKOUT
500kHz
60.4k
330pF
33pF
36.5k
0.1µF
3692 TA01a
CLKOUT
SW1
SW2
V_IN = 12V
1µs/DIV
CLKOUT
SW1
SW2
V_IN = 24V
1µs/DIV
For more information www.linear.com/3692
3692 TA01b
3692 TA01c
3692fa
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