Pin Functions - Analog Devices LINEAR LT8491 Manual

LT8491

PIN FUNCTIONS

FBIR (Pin 1): A/D Input Pin. Connects to FBIN pin to mea-
sure input voltage.
CA (Pin 2): A/D Input Pin. Connects to a resistor divider
2
to program the I C address. This pin is measured during
the power up sequence.
TEMPSENSE (Pin 3): A/D Input Pin. Connects to a therm-
istor divider network for sensing battery temperature or a
resistor divider if unused. This pin is frequently monitored
for temperature compensation and enforcing temperature
limits.
2
V (Pin 4): I C and Control Logic Power Supply Pin.
DD
Connect this pin to LDO33 and AV
FBOW (Pin 5): PWM Digital Output Pin. Connects to
FBOUT through an RCR network to temperature com-
pensate the battery voltage.
FBIW (Pin 6): PWM Digital Output Pin. Connects to FBIN
through an RCR network to adjust the solar panel voltage
for MPPT.
INTV (Pin 7): Internal 6.35V Regulator Output Pin.
CC
Connects to the GATEV
CC
EXTV when the EXTV
CC CC
otherwise INTV is powered from V
CC
to ground with a minimum 4.7µF ceramic capacitor. See
HW Config: MODE Pin - Current Conduction Mode for
additional details.
SWEN (Pin 8): Switch Enable Pin. Tie to the SWENO pin.
MODE (Pin 9): Mode Pin. The voltage applied to this pin
sets the operating mode of the switching regulator. Tie
this pin to INTV to make discontinuous current mode
CC
active. Tie this pin to ground to operate in discontinuous
current mode for low battery charging currents and con-
tinuous current mode for high battery charging currents.
Do not float this pin. See HW Config: MODE Pin - Current
Conduction Mode for additional details.
IMON_IN (Pin 10): Input Current Monitor and Limit Pin.
The current out of this pin is proportional to the input cur-
rent. See the Applications Information section for more
information.
10
.
DD
pin. INTV is powered from
CC
voltage is higher than 6.4V,
. Bypass this pin
IN
For more information
SHDN (Pin 11): Shutdown Pin. In conjunction with the
UVLO (undervoltage lockout) circuit, this pin is used to
enable/disable the chip. Do not float this pin.
CSN (Pin 12): The (–) Input to the Inductor Current Sense
and Reverse Current Detect Amplifier.
CSP (Pin 13): The (+) Input to the Inductor Current Sense
and Reverse Current Detect Amplifier. The V
and built-in offsets between the CSP and CSN pins set the
inductor current trip threshold.
LDO33 (Pin 14): 3.3V Regulator Output. This pin pro-
vides power to the V and AV
DD
ground with a minimum 4.7µF ceramic capacitor.
FBIN (Pin 15): Input Feedback Pin. This pin is connected
to the input error amplifier input.
FBOUT (Pin 16): Output Feedback Pin. This pin connects
the error amplifier input to an external resistor divider
from the output.
IMON_OUT (Pin 17): Output Current Monitor and Limit
Pin. The current out of this pin is proportional to the aver-
age output current. See the Applications Information sec-
tion for more information.
V (Pin 18): Error Amplifier Output Pin. Tie the external
C
compensation network to this pin.
SS (Pin 19): Soft-Start Pin. Place 100nF of capacitance
from this pin to ground. Upon start-up, this pin will be
charged by an internal resistor to 2.5V.
CLKOUT (Pin 20): Switching Regulator Clock Output Pin.
CLKOUT will toggle at the same frequency as the switch-
ing regulator oscillator (OSC1 on the Block Diagram) or
as the SYNC pin but is approximately 180° out-of-phase.
CLKOUT can also be used as a temperature monitor of the
switching regulator since the CLKOUT duty cycle varies
linearly with the junction temperature of the switching
regulator. It is connected to the CLKDET pin through an
RC filter. The CLKOUT pin can drive capacitive loads up
to 200pF.
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pin voltage
C
pins. Bypass this pin to
DD
Rev. 0