Datasheet

LTC4160/LTC4160-1
10
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PIN FUNCTIONS
OVGATE (Pin 1): Overvoltage Protection Gate Output.
Connect OVGATE to the gate pin of an external N-channel
MOSFET. The source of the transistor should be connected
to V
BUS
and the drain should be connected to the product’s
DC input connector. In the absence of an overvoltage con-
dition, this pin is connected to an internal charge pump
capable of creating sufficient overdrive to fully enhance
the MOSFET. If an overvoltage condition is detected, OV-
GATE is brought rapidly to GND to prevent damage to the
LTC4160/LTC4160-1. OVGATE works in conjunction with
OVSENS to provide this protection.
OVSENS (Pin 2): Overvoltage Protection Sense Input.
OVSENS should be connected through a 6.2k resistor to
the input power connector and the drain of an external
N-channel MOSFET. When the voltage on this pin exceeds
V
OVCUTOFF,
the OVGATE pin will be pulled to GND to dis-
able the MOSFET and protect the LTC4160/LTC4160-1.
The OVSENS pin shunts current during an overvoltage
transient in order to keep the pin voltage at 6V.
VBUSGD (Pin 3): Logic Output. This is an open-drain
output which indicates that V
BUS
is above V
UVLO
and
V
DUVLO
. VBUSGD requires a pull-up resistor and/or LED
to provide indication.
FAULT (Pin 4): Logic Output. This in an open-drain output
which indicates a bad battery fault when the charger is
enabled or a short circuit condition on V
BUS
when the
bidirectional PowerPath switching regulator is in step-up
mode (On-The-Go). FAULT requires a pull-up resistor
and/or LED to provide indication.
ID (Pin 5): Logic Input. This pin independently enables
the bidirectional switching regulator to step-up the volt-
age on V
OUT
and provide a 5V output on the V
BUS
pin for
USB On-The-Go applications. If the host does not power
down V
BUS
then connect this pin directly to the ID pin of
a USB micro-AB receptacle. Active low. Has an internal
2.5µA pull-up current source.
ENOTG (Pin 6): Logic Input. This pin independently enables
the bidirectional switching regulator to step-up the voltage
on V
OUT
and provide a 5V output on the V
BUS
pin for USB
On-The-Go applications. Active high. Has an internal 1.8µA
pull-down current source.
ENCHARGER (Pin 7): Logic Input. This pin enables the
battery charger. Active low. Has an internal 1.8µA pull-
down current source.
PROG (Pin 8): Charge Current Program and Charge Cur-
rent Monitor Pin. Connecting a 1% resistor from PROG to
ground, programs the charge current. If sufficient input
power is available in constant-current mode, this pin servos
to 1V. The voltage on this pin always represents the actual
charge current by using the following formula:
I
V
R
BAT
PROG
PROG
= • 1030
CHRG (Pin 9): Logic Output. This is an open-drain out-
put that indicates whether the battery is charging or not
charging. CHRG requires a pull-up resistor and/or LED to
provide indication.
IDGATE (Pin 10): Ideal Diode Amplifier Output. This pin
controls the gate of an optional external P-channel MOSFET
used as an ideal diode between V
OUT
and BAT. The external
ideal diode operates in parallel with the internal ideal diode.
The source of the P-channel MOSFET should be connected
to V
OUT
and the drain should be connected to BAT. If the
external ideal diode MOSFET is not used, IDGATE should
be left floating.
BAT (Pin 11): Single Cell Li-Ion Battery Pin. Depending on
available V
BUS
power, a Li-Ion battery on BAT will either
deliver power to V
OUT
through the ideal diode or be charged
from V
OUT
via the battery charger.
V
OUT
(Pin 12): Output Voltage of the Bidirectional Power-
Path Switching Regulator in Step-Down Mode and Input
Voltage of the Battery Charger. The majority of the portable
product should be powered from V
OUT
. The LTC4160/
LTC4160-1 will partition the available power between the
external load on V
OUT
and the internal battery charger.
Priority is given to the external load and any extra power
is used to charge the battery. An ideal diode from BAT to
V
OUT
ensures that V
OUT
is powered even if the load exceeds
the allotted power from V
BUS
or if the V
BUS
power source
is removed. In On-The-Go mode, this pin delivers power
to V
BUS
via the SW pin. V
OUT
should be bypassed with a
low impedance multilayer ceramic capacitor.