LT8708-1
11
Rev 0
BOOST1, BOOST2 (Pin 24, Pin 19): Boosted Floating
Driver Supply. The (+) terminal of the bootstrap capacitor
connects here. The BOOST1 pin swings from a diode volt-
age below GATEV
CC
up to V
IN
+ GATEV
CC
. The BOOST2
pin swings from a diode voltage below GATEV
CC
up to
V
OUT
+ GATEV
CC
.
TG1, TG2 (Pin 23, Pin 20): Top Gate Drive. Drives the
top N-channel MOSFETs with voltage swings equal to
GATEV
CC
superimposed on the switch node voltages.
SW1, SW2 (Pin 22, Pin 21): Switch Nodes. The (–) ter-
minals of the bootstrap capacitors connect here.
RVSOFF
(Pin 25): Reverse Conduction Disable Pin. This
is an input/output open-drain pin that requires a pull-up
resistor. Pulling this pin low disables reverse current oper-
ation. Typically, connect this pin to the LT8708’s
RVSOFF
pin. See the Unidirectional and Bidirectional Conduction
section for more information.
VOUTLOMON (Pin 26): V
OUT
Low Voltage Monitor
Pin. Connect a ±1% resistor divider between V
OUT
,
VOUTLOMON and GND to set an undervoltage level on
V
OUT
. When V
OUT
is lower than this level, reverse conduc-
tion is disabled to prevent drawing current from V
OUT
. See
the Applications Information section for more information.
VINHIMON (Pin 27): V
IN
High Voltage Monitor Pin.
Connect a ±1% resistor divider between V
IN
, VINHIMON
and GND in order to set an overvoltage level on V
IN
. When
V
IN
is higher than this level, reverse conduction is dis-
abled to prevent current flow into V
IN
. See the Applications
Information section for more information.
ICP (Pin 28): Positive V
OUT
Current Command Pin.
The voltage on this pin determines the positive V
OUT
current for LT8708-1 to regulate to. Connect this pin
to LT8708’s ICP pin. See the Applications Information
section for more information.
EXTV
CC
(Pin 29): External V
CC
Input. When EXTV
CC
exceeds 6.4V (typical), INTV
CC
will be powered from this
pin. When EXTV
CC
is lower than 6.4V, the INTV
CC
will be
powered from V
INCHIP
. It is recommended to use the same
value bypass cap as the master LT8708.
CSPOUT (Pin 30): The (+) Input to the V
OUT
Current
Monitor Amplifier. This pin and the CSNOUT pin measure
the voltage across the sense resistor, R
SENSE2
, to provide
the V
OUT
current signals. It is recommended to use the
same value R
SENSE2
between the CSPOUT and CSNOUT
pins as the master LT8708. See Applications Information
section for proper use of this pin.
CSNOUT (Pin 31): The (–) Input to the V
OUT
Current
Monitor Amplifier. See Applications Information section
for proper use of this pin.
CSNIN (Pin 32): The (–) Input to the V
IN
Current Monitor
Amplifier. This pin and the CSPIN pin measure the volt-
age across the sense resistor, R
SENSE1
, to provide the
V
IN
current signals. Connect this pin to V
IN
when not in
use. See Applications Information section for proper use
of this pin.
CSPIN (Pin 33): The (+) Input to the V
IN
Current
Monitor Amplifier. Connect this pin to V
IN
when not
in use. See Applications Information section for proper
use of this pin.
V
INCHIP
(Pin 34): Main Input Supply Pin for the LT8708-1.
It must be locally bypassed to ground. It is recommended
to use the same value bypass cap as the master LT8708.
INTV
CC
(Pin 35): 6.35V Regulator Output. Must be con-
nected to the GATEV
CC
pin. INTV
CC
is powered from
EXTV
CC
when the EXTV
CC
voltage is higher than 6.4V,
otherwise INTV
CC
is powered from V
INCHIP.
Bypass this
pin to ground with a minimum 4.7µF ceramic capacitor.
It is recommended to use the same value bypass cap as
the master LT8708.
SWEN (Pin 36): Switching Regulator Enable Pin. Tie high
through a resistor to enable the switching. Ground to dis-
able switching. This pin is pulled down during shutdown, a
thermal lockout or when an internal UVLO (Under Voltage
Lockout) is detected. Do not float this pin. Connect this
pin to the LT8708’s SWEN pin for synchronized start-up.
See the Start-Up: SWEN Pin section for more details.
PIN FUNCTIONS
