LT8610A/LT8610AB Series
42V, 3.5A Synchronous
Step-Down Regulator with
2.5µA Quiescent Current
FEATURES
DESCRIPTION
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LT8610 Feature Set, Plus:
The LT®8610A/LT8610AB series are compact, high ef-
ficiency, high speed synchronous monolithic step-down
switching regulators that consume only 2.5µA of quies-
cent current. Compared to the LT8610, they have higher
maximum output currents of 3.5A and a faster minimum
switch-on time of 30ns. The LT8610A has the same low
ripple burst mode performance of the LT8610, while the
LT8610AB has even higher light load efficiency.
3.5A Maximum Output Current
Fast 30ns Minimum Switch-On Time
Improved Burst Mode Efficiency (LT8610AB Only)
Improved EMI
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Wide Input Voltage Range: 3.4V to 42V
Ultralow Quiescent Current Burst Mode® Operation:
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2.5μA I Regulating 12V to 3.3V
Q
IN
OUT
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Fixed Output Voltages: 3.3V, 5V
The other features of the LT8610 remain unchanged in the
LT8610A/LT8610ABseries.ASYNCpinallowssynchroni-
zation to an external clock. The EN/UV pin has an accurate
Output Ripple < 10mV (LT8610A Only)
P-P
High Efficiency Synchronous Operation:
95% Efficiency at 1A, 5V
93% Efficiency at 1A, 3.3V
from 12V
from 12V
IN
OUT
IN
1V threshold for V undervoltage lockout or shut down.
IN
OUT
A capacitor on the TR/SS pin programs the output voltage
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Low Dropout Under All Conditions: 200mV at 1A
Safely Tolerates Inductor Saturation in Overload
Adjustable and Synchronizable Frequency:
200kHz to 2.2MHz
Accurate 1V Enable Pin Threshold
Output Soft-Start and Tracking
Small Thermally Enhanced 16-Lead MSOP Package
ramp rate during startup. The PG flag signals when V
OUT
is within ±±9 of the programmed output voltage as well
as fault conditions.
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OUTPUT
CURRENT
MINIMUM
ON TIME
1mA LOAD
EFFICIENCY**
LT8610*
LT8610A
LT8610AB
2.5A
3.5A
3.5A
50ns
30ns
30ns
829
829
±19
APPLICATIONS
*See LT8610 data sheet. **V = 12V, V
= 3.3V, L = 4.7µH
IN
OUT
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Automotive and Industrial Supplies
GSM Power Supplies
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.
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TYPICAL APPLICATION
LT8610AB Efficiency at 5VOUT
5V 3.5A Step-Down Converter
100
V
IN
V
BST
IN
5.5V TO 42V
90
80
70
60
50
0.1µF
4.7µH
4.7µF
EN/UV
V
OUT
LT8610AB-5
5V
SW
PG
47µF
×2
3.5A
SYNC
BIAS
10nF
TR/SS
V
OUT
1µF
INTV
CC
RT
GND
V
V
V
= 12V
= 24V
= 36V
IN
IN
IN
40
30
60.4k
= 700kHz
0.1
1
10
100
1000
f
SW
8610ab TA01a
LOAD CURRENT (mA)
8610ab TA01b
8610abfa
1
For more information www.linear.com/LT8610A