LT8613_15 Datasheet, PDF (1/24 Pages) Linear Technology – 42V, 6A Synchronous Step-Down Regulator with Current Sense and 3A Quiescent Current

Features
n _{Rail-to-Rail Current Sense Amplifier with Monitor}
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 _{Low EMI}
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 _{CCCV Power Supplies}
LT8613
42V, 6A Synchronous
Step-Down Regulator with
Current Sense and 3µA
Quiescent Current
Description
The LT^®8613 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.
The built-in current sense amplifier with monitor and
control pins allows accurate input or output current
regulation and limiting. 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 current 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 LT8613 reduc-
ing 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 LT8613 is available in a small 28-lead 3mm × 6mm
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 Step-Down Converter with 6A Output Current Limit
V_IN
5.8V TO 42V
V_IN
BST
10µF _{ON OFF EN/UV}
SYNC
LT8613
SW
IMON
ICTRL
ISP
ISN
BIAS
INTV_CC
PG
TR/SS
10µF
RT
FB
1µF
60.4k
PGND GND
0.1µF
3.9µH
8mΩ
1µF
V_OUT
5V
6A
10pF
1M
243k
100µF
f_SW = 700kHz
L: EPCOS B82559
8613 TA01a
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
8613 TA01b
For more information www.linear.com/LT8613
8613f
1