LT8610A_15 Datasheet, PDF (1/26 Pages) Linear Technology – 42V, 3.5A Synchronous Step-Down Regulator with 2.5A Quiescent Current

FEATURES
n _{LT8610 Feature Set, Plus:}
3.5A Maximum Output Current
Fast 30ns Minimum Switch-On Time
Improved Burst Mode Efficiency (LT8610AB Only)
Improved EMI
n _{Wide Input Voltage Range: 3.4V to 42V}
n _{Ultralow Quiescent Current Burst Mode}^® _Operation:
2.5μA I_Q Regulating 12V_IN to 3.3V_OUT
n _{Fixed Output Voltages: 3.3V, 5V}
n _{Output Ripple < 10mVP-P (LT8610A Only)}
n _{High Efficiency Synchronous Operation:}
95% Efficiency at 1A, 5V_OUT from 12V_IN
93% Efficiency at 1A, 3.3V_OUT from 12V_IN
n _{Low Dropout Under All Conditions: 200mV at 1A}
n _{Safely Tolerates Inductor Saturation in Overload}
n _{Adjustable and Synchronizable Frequency:}
200kHz to 2.2MHz
n _{Accurate 1V Enable Pin Threshold}
n _{Output Soft-Start and Tracking}
n _{Small Thermally Enhanced 16-Lead MSOP Package}
APPLICATIONS
n _{Automotive and Industrial Supplies}
n _{GSM Power Supplies}
LT8610A/LT8610AB Series
42V, 3.5A Synchronous
Step-Down Regulator with
2.5µA Quiescent Current
DESCRIPTION
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.
The other features of the LT8610 remain unchanged in the
LT8610A/LT8610AB series. A SYNC pin allows synchroni-
zation to an external clock. The EN/UV pin has an accurate
1V threshold for V_IN undervoltage lockout or shut down.
A capacitor on the TR/SS pin programs the output voltage
ramp rate during startup. The PG flag signals when V_OUT
is within ±9% of the programmed output voltage as well
as fault conditions.
OUTPUT
CURRENT
MINIMUM
ON TIME
1mA LOAD
EFFICIENCY**
LT8610*
2.5A
50ns
82%
LT8610A
3.5A
30ns
82%
LT8610AB
3.5A
30ns
91%
*See LT8610 data sheet. **V_IN = 12V, V_OUT = 3.3V, L = 4.7µH
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
V_IN
5.5V TO 42V
5V 3.5A Step-Down Converter
4.7µF
10nF
1µF
V_IN
BST
EN/UV
PG ^LT8610AB-5 SW
SYNC
BIAS
TR/SS
INTV_CC
RT
V_OUT
GND
60.4k
0.1µF
4.7µH
f_SW = 700kHz
8610ab TA01a
V_OUT
5V
47µF _3.5A
×2
LT8610AB Efficiency at 5V_OUT
100
90
80
70
60
50
40
30
0.1
V_IN = 12V
V_IN = 24V
V_IN = 36V
1
10
100
LOAD CURRENT (mA)
1000
8610ab TA01b
For more information www.linear.com/LT8610A
8610abfa
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