LTM4636
8
4636f
pin FuncTions
SGND (F4, G4):
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 18.
INTV
CC
(F6):
Internal 5.5V LDO for Driving the Control
Circuitry in the LTM4636. INTV
CC
is controlled and enabled
when RUNC is activated high. Tie to V
IN
, when 4.7V ≤ V
IN
≤ 5.5V, minimum V
IN
= 4.2V.
FREQ (G5):
A resistor can be applied from this pin to
ground to set the operating frequency. This pin sources
20µA. See the Applications Information section.
PHASMD (G7):
This pin can be voltage programmed to
change the phase relationship of the CLKOUT pin with
reference to the internal clock or an input synchronized
clock. The INTV
CC
(5.5V) output can be voltage divided
down to the PHASMD pin to set the particular phase. The
Electrical Characteristics show the different settings to
select a particular phase. See the Applications Informa-
tion section.
RUNP (G8):
This pin enables the PV
CC
supply. This pin
can be connected to V
IN
, or tie to ground when connecting
PV
CC
to V
IN
≤ 5.5V. RUNP needs to sequence up before
RUNC. A 15k resistor from PV
CC
to RUNC with a 0.1µF
capacitor will provide enough delay. In parallel operation
with multiple LTM4636s, the resistor can be reduced in
value by N times and the 0.1µF can be increased N times.
See Applications Information section. RUNP can be used to
set the minimum UVLO with a voltage divider. See Figure 1.
NC (G9):
No Connection.
PV
CC
(F9):
5V Power Output and Power for Internal Power
MOSFET Drivers. The regulator can power 50mA of external
sourcing for additional use. Place a 22µF ceramic filter
capacitor on this pin to ground. When V
IN
< 5.5V, tie V
IN
and PV
CC
together along with INTV
CC
. Then tie RUNP to
GND. If V
IN
> 5.5V then operate PV
CC
regulator as normal.
See the Typical Application examples.
TEMP
+
(G12):
Temperature Monitor. An internal diode
connected NPN transistor. See the Applications Informa-
tion section.
TEMP
–
(G11):
Low Side of the Internal Temperature
Monitor.
CLKOUT (G3):
Clock out signal that can be phase selected
to the main internal clock or synchronized clock using
the PHASMD pin. CLKOUT can be used for multiphase
applications. See the Applications Information section.
TEST1 (H4), TEST2 (F5), TEST3 (H2), TEST4 (E11), GMON
(H9):
These are test pins used in the final production test
of the part. Leave floating.
V
IN
(H5-H6, J4-J7, K4-K8, L4-L8, M4-M8):
Power Input
Pins. Apply input voltage between these pins and GND
pins. Recommend placing input decoupling capacitance
directly between V
IN
and GND pins.
PWM (H7):
PWM output that drives the power stage.
Primarily used for test, but can be monitored in debug
or testing.
TMON (H8):
Temperature Monitor Pin. Internal temperature
monitor, varies from 1V at 25°C to 1.44V at 150°C, disables
power stage at 150°C. If this feature is not desired, then
tie the TMON pin to GND.
SW (L11, K11):
These are pin connections to the internal
switch node for test evaluation and monitoring. An R-C
snubber can be placed from the switch pins to GND to
eliminate any high frequency ringing. See the Applications
Information section.
