Datasheet

LTM4627
7
4627fc
For more information www.linear.com/LTM4627
V
IN
(A1-A6, B1-B6, C1-C6): 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.
V
OUT
(J1-J10, K1-K11, L1-L11, M1-M11): Power Output
Pins. Apply output load between these pins and GND
pins. Recommend placing output decoupling capacitance
directly between these pins and GND pins. Review Table 4.
GND (B7, B9, C7, C9, D1-D6, D8, E1-E7, E9, F1-F9, G1-G9,
H1-H9): Power Ground Pins for Both Input and Output
Returns.
PGOOD (F11, G12): Output Voltage Power Good Indicator.
Open-drain logic output that is pulled to ground when the
output voltage exceeds a ±10% regulation window. Both
pins are tied together internally.
SGND (G11, H11, H12): Signal Ground Pin. Return ground
path for all analog and low power circuitry. Tie a single
connection to the output capacitor GND in the application.
See layout guidelines in Figure 17.
MODE_PLLIN (A8): Forced Continuous Mode, Burst Mode
Operation, or Pulse-Skipping Mode Selection Pin and
External Synchronization Input to Phase Detector Pin.
Connect this pin to INTV
CC
to enable pulse-skipping mode
of operation. Connect to ground to enable forced continuous
mode of operation. Floating this pin will enable Burst Mode
operation. A clock on this pin will enable synchronization
with forced continuous operation. See the Applications
Information section.
f
SET
(B12): A resistor can be applied from this pin to
ground to set the operating frequency, or a DC voltage
can be applied to set the frequency. See the Applications
Information section.
PIN FUNCTIONS
TRACK/SS (A9): Output Voltage Tracking Pin and Soft-
Start Inputs. The pin has a 1.2µA pull-up current source.
A capacitor from this pin to ground will set a soft-start
ramp rate. In tracking, the regulator output can be tracked
to a different voltage. The different voltage is applied to
a voltage divider then the slave output’s track pin. This
voltage divider is equal to the slave output’s feedback
divider for coincidental tracking. See the Applications
Information section.
V
FB
(F12): The Negative Input of the Error Amplifier.
Internally, this pin is connected to V
OUT_LCL
with a
60.4k precision resistor. Different output voltages can
be programmed with an additional resistor between V
FB
and ground pins. In PolyPhase
®
operation, tying the
V
FB
pins together allows for parallel operation. See the
Applications Information section for details.
COMP (A11): Current Control Threshold and Error Amplifier
Compensation Point. The current comparator threshold
increases with this control voltage. Tie all COMP pins
together for parallel operation. The device is internally
compensated.
RUN: (A10) Run Control Pin. A voltage above 1.4V will turn
on the module. A 5.1V Zener diode to ground is internal
to the module for limiting the voltage on the RUN pin to
5V, and allowing a pull-up resistor to V
IN
for enabling the
device. Limit current into the RUN pin to ≤ 2mA.
INTV
CC
: (A7, D9) Internal 5V LDO for Driving the Control
Circuitry and the Power MOSFET Drivers. Both pins are
internally connected. The 5V LDO has a 100mA current limit.
EXTV
CC
(E12): External power input to an internal control
switch allows an external source greater than 4.7V, but
less than 6V to supply IC power and bypass the internal
INTV
CC
LDO. EXTV
CC
must be less than V
IN
at all times
during power-on and power-off sequences. See the Ap-
plications Information section.