LT8612_15 Datasheet, PDF (1/20 Pages) Linear Technology – 42V, 6A Synchronous Step-Down Regulator with 3A Quiescent Current

Features
n _{Wide Input Voltage Range: 3.4V to 42V}
n _{Ultralow Quiescent Current Burst Mode}^® _Operation:
3μA I_Q Regulating 12V_IN to 3.3V_OUT
Output Ripple < 10mV_P-P
n _{High Efficiency Synchronous Operation:}
95% Efficiency at 3A, 5V_OUT from 12V_IN
94% Efficiency at 3A, 3.3V_OUT from 12V_IN
n _{Fast Minimum Switch-On-Time: 40ns}
n _{Low Dropout Under All Conditions: 250mV at 3A}
n _{Allows Use Of Small Inductors}
n _{Safely Tolerates Inductor Saturation in Overload}
Conditions
n _{Adjustable and Synchronizable: 200kHz to 2.2MHz}
n _{Current Mode Operation}
n _{Accurate 1V Enable Pin Threshold}
n _{Internal Compensation}
n _{Output Soft-Start and Tracking}
n _{Small Thermally Enhanced 3mm × 6mm 28-Lead}
QFN Package
Applications
n _{Automotive and Industrial Supplies}
n _{General Purpose Step-Down}
n _{GSM Power Supplies}
LT8612
42V, 6A Synchronous
Step-Down Regulator
with 3µA Quiescent
Current
Description
The LT^®8612 is a compact, high efficiency, high speed
synchronous monolithic step-down switching regulator
that consumes only 3µA of quiescent current. Top and
bottom power switches are included with all necessary
circuitry to minimize the need for external components.
Low ripple Burst Mode operation enables high efficiency
down to very low output currents while keeping the output
ripple below 10mV_P-P. A SYNC pin allows synchronization
to an external clock. Internal compensation with peak cur-
rent mode topology allows the use of small inductors and
results in fast transient response and good loop stability.
The EN/UV pin has an accurate 1V threshold and can be
used to program V_IN undervoltage lockout or to shut down
the LT8612 reducing the input supply current to 1µA. A
capacitor on the TR/SS pin programs the output voltage
ramp rate during start-up. The PG flag signals when V_OUT
is within ±9% of the programmed output voltage as well
as fault conditions. The LT8612 is available in a small
3mm × 6mm 28-lead QFN package with exposed pad for
low thermal resistance.
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
5V 6A Step-Down Converter
V_IN
5.6V TO 42V
10µF
10nF
1µF
V_IN
BST
EN/UV
PG
SW
LT8612
SYNC
BIAS
TR/SS
FB
INTV_CC
RT PGND GND
60.4k
0.1µF
3.9µH
1M
10pF
243k
f_SW = 700kHz
L: EPCOS B82559
8612 TA01a
V_OUT
5V
100µF ^6A
1210
Efficiency at 5V_OUT
100
V_IN = 12V
95
90
V_IN = 24V
85
80
75
70
65 f_SW = 700kHz
L = 3.9µH
60
0
1
2
3
4
LOAD CURRENT (A)
5
6
8612 TA01b
For more information www.linear.com/LT8612
8612f
1