Datasheet

LTM4628
8
4628fe
For more information www.linear.com/LTM4628
PIN FUNCTIONS
TRACK1, TRACK2 (E5, D8): Output Voltage Tracking Pin
and Soft-Start Inputs. Each channel has a 1.3µA pull-up
current source. When one channel is configured to be
master of the two channels, then a capacitor from this pin
to ground will set a soft-start ramp rate. The remaining
channel can be set up as the slave, and have the master’s
output applied through a voltage divider to the slave out
-
put’s track pin. This voltage divider is equal to the slave
output’s
feedback divider for coincidental tracking. See
the Applications Information section.
COMP1, COMP2 (E6, E7): Current control threshold and
error amplifier compensation point for each channel. The
current comparator threshold increases with this control
voltage. Tie the COMP pins together for parallel operation.
The device is internal compensated.
DIFFP (E8): Positive input of the remote sense amplifier.
This pin is connected to the remote sense point of the output
voltage. Use of the remote sense amplifier is limited to an
output voltage between 0.6V and 3.3V inclusive. Connect to
GND if not used. See the Applications Information section.
DIFFN (E9): Negative input of the remote sense amplifier.
This pin is connected
to the remote sense point of the
output GND. See the Applications Information section.
MODE_PLLIN
(F4): Force Continuous Mode, Burst Mode
Operation, or Pulse-Skipping Mode Selection Pin and
External Synchronization Input to Phase Detector Pin.
Connect this pin to SGND to force both channels into
force continuous mode of operation. Connect to INTV
CC
to enable pulse-skipping mode of operation. Leaving the
pin floating will enable Burst Mode operation. A clock on
the pin will force both channels into continuous mode of
operation and synchronized to the external clock applied
to this pin.
RUN1, RUN2 (F5, F9): Run Control Pin. A voltage above
1.25V will turn on each channel in the module. A voltage
below 1.25V on the RUN pin will turn off the related chan
-
nel. Each
RUN pin has a 1µA pull-up current, once the
RUN
pin reaches 1.2V an additional 4.5µA pull-up current
is added to this pin.
DIFFOUT (F8): Internal Remote Sense Amplifier Output.
Connect this pin to V
OUTS1
or V
OUTS2
depending on which
output is using remote sense. In parallel operation con-
nect one
of the V
OUTS
pin to DIFFOUT for remote sensing.
Leave floating if the remote sense amplifier is not used.
SW1,
SW2 (G2, G11): Switching node of each channel
that is used for testing purposes. Also an R-C snubber
network can be applied to reduce or eliminate switch node
ringing, otherwise leave floating. See the Applications
Information section.
PHASMD (G4): Connect this pin to SGND, INTV
CC
, or float-
ing this pin to select the phase of CLKOUT to 60 degrees,
120 degrees, and 90 degrees respectively.
CLKOUT
(G5): Clock output with phase control using the
PHASMD pin to enable multiphase operation between
devices. See the Applications Information section.
PGOOD1, PGOOD2 (G9, G8): Output Voltage Power
Good Indicator. Open drain logic output that is pulled to
ground when the output voltage is not within ±7.5% of
the regulation point.
INTV
CC
(H8): Internal 5V Regulator Output. The control
circuits and internal gate drivers are powered from this
voltage. INTV
CC
is controlled and enabled when RUN1 or
RUN2 is activated high. Decouple this pin to PGND with
a 4.7µF low ESR tantalum or ceramic.
TEMP (J6): Onboard Temperature Diode for Monitoring
the VBE Junction Voltage Change with Temperature. See
the Applications Information section.
EXTV
CC
(J7): External power input that is enabled through
a switch to INTV
CC
whenever EXTV
CC
is greater than 4.7V.
Do not exceed 6V on this input, and connect this pin to
V
IN
when operating V
IN
on 5V. An efficiency increase will
occur that is a function of the (V
IN
– INTV
CC
) multiplied by
power MOSFET driver current. Typical current requirement
is 30mA. V
IN
must be applied before EXTV
CC
, and EXTV
CC
must be removed before V
IN
.
V
IN
(M2-M11, L2-L11, J2-J4, J9-J11, K2-K4, K9-K11):
Power Input Pins. Apply input voltage between these pins
and GND pins. Recommend placing input decoupling
capacitance directly between V
IN
pins and GND pins.
(Recommended to Use Test Points to Monitor Signal Pin Connections.)