LTM4606V View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTM4606V' PDF : 28 Pages View PDF
LTM4606
OPERATION
Power Module Description
The LTM4606 is a standalone non-isolated switching mode
DC/DC power supply. It can deliver up to 6A of DC output
current with some external input and output capacitors.
This module provides precisely regulated output voltage
programmable via one external resistor from 0.6VDC to
5.0VDC over a 4.5V to 28V input voltage range. The typical
application schematic is shown in Figure 20.
The LTM4606 has an integrated constant on-time current
mode regulator, ultralow RDS(ON) FETs with fast switching
speed and integrated Schottky diodes. The typical switch-
ing frequency is 800kHz. With current mode control and
internal feedback loop compensation, the LTM4606 module
has sufficient stability margins and good transient per-
formance under a wide range of operating conditions and
with a wide range of output capacitors, even all ceramic
output capacitors.
Current mode control provides cycle-by-cycle fast current
limiting. Besides, foldback current limiting is provided in an
overcurrent condition while VFB 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 M1 is turned off
and bottom FET M2 is turned on and held on until the
overvoltage condition clears.
Input filter and noise cancellation circuits reduce the noise
coupling to I/O sides, and ensure the electromagnetic
interference (EMI) to meet the limits of CISPR 22 and
CISPR 25.
Pulling the RUN pin below 1V forces the controller into
its shutdown state, turning off both M1 and M2. At low
load currents, discontinuous mode (DCM) operation
can be enabled to achieve higher efficiency compared to
continuous mode (CCM) by setting the FCB pin higher
than 0.6V.
When the DRVCC pin is connected to INTVCC an integrated
5V linear regulator powers the internal gate drivers. If a
5V external bias supply is applied on the DRVCC 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 MPGM, MARG0, and MARG1 pins are used to sup-
port voltage margining, where the percentage of margin
is programmed by the MPGM pin, and the MARG0 and
MARG1 selected margining. The PLLIN pin provides fre-
quency synchronization of the device to an external clock.
The TRACK/SS pin is used for power supply tracking and
soft-start programming.
4606f
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