LTM4601 Datasheet, PDF (9/28 Pages) Linear Technology – 12A DC/DC μModules with PLL, Output Tracking and Margining

LTM4601/LTM4601-1
DECOUPLI G REQUIRE E TS T_A = 25°C, V_IN = 12V. Use Figure 1 configuration.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
C_IN
External Input Capacitor Requirement I_OUT = 12A, 3× 10µF Ceramics
(V_IN = 4.5V to 20V, V_OUT = 1.5V)
C_OUT
External Output Capacitor Requirement I_OUT = 12A
(V_IN = 4.5V to 20V, V_OUT = 1.5V)
20
30
µF
100
200
µF
U
OPERATIO
Power Module Description
The LTM4601 is a standalone nonisolated switching mode
DC/DC power supply. It can deliver up to 12A of DC output
current with some external input and output capacitors.
This module provides precisely regulated output voltage
programmable via one external resistor from 0.6V_DC to
5.0V_DC over a 4.5V to 20V wide input voltage. The typical
application schematic is shown in Figure 18.
The LTM4601 has an integrated constant on-time current
mode regulator, ultralow R_DS(ON) FETs with fast switch-
ing speed and integrated Schottky diodes. The typical
switching frequency is 850kHz at full load. With current
mode control and internal feedback loop compensation,
the LTM4601 module has sufficient stability margins and
good transient performance under a wide range of operat-
ing conditions and with a wide range of output capacitors,
even all ceramic output capacitors.
Current mode control provides cycle-by-cycle fast current
limit. Besides, foldback current limiting is provided in an
overcurrent condition while V_FB drops. Internal overvoltage
and undervoltage comparators pull the open-drain PGOOD
output low if the output feedback voltage exits a ±10%
window around the regulation point. Furthermore, in an
overvoltage condition, internal top FET Q1 is turned off
and bottom FET Q2 is turned on and held on until the
overvoltage condition clears.
Pulling the RUN pin below 1V forces the controller into its
shutdown state, turning off both Q1 and Q2. At low load
current, the module works in continuous current mode by
default to achieve minimum output voltage ripple.
When DRV_CC pin is connected to INTV_CC an integrated
5V linear regulator powers the internal gate drivers. If a
5V external bias supply is applied on the DRV_CC pin, then
an efficiency improvement will occur due to the reduced
power loss in the internal linear regulator. This is especially
true at the higher input voltage range.
The LTM4601 has a very accurate differential remote
sense amplifier with very low offset. This provides for
very accurate remote sense voltage measurement. The
MPGM pin, MARG0 pin and MARG1 pin are used to sup-
port voltage margining, where the percentage of margin
is programmed by the MPGM pin, and the MARG0 and
MARG1 select margining.
The PLLIN pin provides frequency synchronization of the
device to an external clock. The TRACK/SS pin is used for
power supply tracking and soft-start programming.
4601f
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