Datasheet

LTM4637
7
4637fc
For more information www.linear.com/LTM4637
pin FuncTions
V
IN
(A1-A6, B1-B6, C1-C6): Power Input Pins. Apply
input voltage between these and GND pins. Recommend
placing input decoupling capacitance directly between
V
IN
and GND pins.
V
OUT
(J1-J10, K1-K11, L1-L11, M1-M11): Power Output
Pins. Apply output load between these and GND pins. Rec-
ommend placing
output decoupling capacitance between
these pins and GND pins. Review Table 5.
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.
PGOOD (F11, G12): Output Voltage Power Good Indica
-
tor. Open
-drain logic output 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. See layout
guidelines in Figure 21.
TEMP (D10): Temperature Monitor. See Applications
Information section.
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.
Connect to ground to enable forced continuous mode.
Floating this pin will enable Burst Mode operation. A clock
on this pin will enable synchronization with forced continu
-
ous 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.
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. 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.
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. INTV
CC
is controlled and enabled when RUN is
activated high.
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 Applications
Information section. 5V output application can connect the
5V output to this pin to improve efficiency. The 5V output
is connected to EXTV
CC
in the 5V derating curves.
V
OUT_LCL
: (L12) This pin connects to V
OUT
through a 1M
resistor, and to V
FB
with a 60.4k resistor. The remote sense
amplifier output DIFF_OUT is connected to V
OUT_LCL
, and
drives the 60.4k top feedback resistor in remote sensing
applications. When the remote sense amplifier is used,
DIFF_OUT effectively eliminates the 1MΩ from V
OUT
to
V
OUT_LCL
. When the remote sense amplifier is not used,
then connect V
OUT_LCL
to V
OUT
directly.
PACKAGE ROW AND COLUMN LABELING MAY VARY
AMONG µModule PRODUCTS. REVIEW EACH PACKAGE
LAYOUT CAREFULLY.