LT8612
42V, 6A Synchronous
Step-Down Regulator with
3A Quiescent Current
FEATURES DESCRIPTION
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Wide Input Voltage Range: 3.4V to 42V
The LT 8612 is a compact, high efficiency, high speed
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Ultralow Quiescent Current Burst Mode Operation:
synchronous monolithic step-down switching regulator
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3A I Regulating 12V to 3.3V
that consumes only 3A of quiescent current. Top and
Q IN OUT
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Output Ripple < 10mV
bottom power switches are included with all necessary
P-P
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High Efficiency Synchronous Operation:
circuitry to minimize the need for external components.
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95% Efficiency at 3A, 5V from 12V
Low ripple Burst Mode operation enables high efficiency
OUT IN
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94% Efficiency at 3A, 3.3V from 12V
down to very low output currents while keeping the output
OUT IN
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Fast Minimum Switch-On-Time: 40ns
ripple below 10mV . A SYNC pin allows synchronization
P-P
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Low Dropout Under All Conditions: 250mV at 3A
to an external clock. Internal compensation with peak cur-
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Allows Use of Small Inductors
rent mode topology allows the use of small inductors and
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Safely Tolerates Inductor Saturation in Overload
results in fast transient response and good loop stability.
Conditions
The EN/UV pin has an accurate 1V threshold and can be
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Adjustable and Synchronizable: 200kHz to 2.2MHz
used to program V undervoltage lockout or to shut down
IN
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Current Mode Operation
the LT8612 reducing the input supply current to 1A. A
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Accurate 1V Enable Pin Threshold
capacitor on the TR/SS pin programs the output voltage
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Internal Compensation
ramp rate during start-up. The PG flag signals when V
OUT
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Output Soft-Start and Tracking
is within 9% of the programmed output voltage as well
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Small Thermally Enhanced 3mm 6mm 28-Lead
as fault conditions. The LT8612 is available in a small
QFN Package
3mm 6mm 28-lead QFN package with exposed pad for
low thermal resistance.
APPLICATIONS
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
of Analog Devices, Inc. All other trademarks are the property of their respective owners.
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Automotive and Industrial Supplies
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General Purpose Step-Down
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GSM Power Supplies
TYPICAL APPLICATION
Efficiency at 5V
OUT
100
5V 6A Step-Down Converter
V = 12V
IN
95
V
IN
V BST
IN
5.6V TO 42V
V = 24V
IN
0.1F
10F
90
EN/UV
3.9H
V
OUT
5V
PG SW
85
LT8612 6A
100F
SYNC BIAS
1210 80
10nF
1M
TR/SS FB 75
1F
10pF
70
INTV
CC
RT PGND GND
65
f = 700kHz
SW
L = 3.9H
60.4k 243k
60
0 1 2 3 4 5 6
LOAD CURRENT (A)
f = 700kHz
SW 8612 TA01a
8612 TA01b
L: EPCOS B82559
8612fa
1
For more information www.linear.com/LT8612
EFFICIENCY (%)LT8612
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
V , EN/UV, PG ..........................................................42V
TOP VIEW
IN
BIAS ..........................................................................25V
FB, TR/SS . .................................................................4V
28 27 26 25
SYNC Voltage . ............................................................6V
SYNC 1 24
FB
Operating Junction Temperature Range (Note 2) TR/SS 2 23 PG
RT 3 22 BIAS
LT8612E ............................................. 40C to 125C
EN/UV 4 21 INTV
CC
LT8612I .............................................. 40C to 125C
V 5 20
BST
IN 29
Storage Temperature Range .................. 65C to 150C
GND
V 6 19
SW
IN
V 7 18 SW
IN
PGND 8 17 SW
PGND 9 16 SW
PGND 10 15
SW
11 12 13 14
UDE PACKAGE
28-LEAD (3mm 6mm) PLASTIC QFN
= 40C/W, = 5C/W
JA JC(PAD)
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB