LTC1731EMS8-8.4#TR Linear Technology, LTC1731EMS8-8.4#TR Datasheet - Page 5

• Manufacturer Part Number: LTC1731EMS8-8.4#TR
• Description: IC BATT CHRG CNTRLR LI-ION 8MSOP
• Manufacturer: Linear Technology

Specifications of LTC1731EMS8-8.4#TR

• Function: Charge Management
• Battery Type: Li-Ion, NiCd, NiMH
• Voltage - Supply: 8.8 V ~ 12 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: LTC1731EMS8-8.4TR; LTC1731EMS88.4TR

PIN
BAT (Pin 1): Battery Sense Input. A bypass capacitor of at
least 10 F is required to keep the loop stable when the
battery is not connected. A precision internal resistive
divider sets the final float potential on this pin. The resistor
divider is disconnected in sleep mode.
CHRG (Pin 2): Open-Drain Charge Status Output. When
the battery is being charged, the CHRG pin is pulled low by
an internal N-channel MOSFET. When the charge current
drops to 10% of the full-scale current for at least 0.32
seconds, the N-channel MOSFET turns off and a 100 A
current source is connected from the CHRG pin to GND.
When the timer runs out or the input supply is removed,
the current source will be disconnected and the CHRG pin
is forced into a high impedance state.
TIMER (Pin 3): Timer Capacitor and Constant-Voltage
Mode Disable Input Pin. A capacitor C
from this pin to ground sets a 30 hour/ F time period for
charge termination. When the TIMER pin is connected to
V
and the IC will operate in constant-current mode only.
Short the TIMER pin to GND to disable the internal timer
and the C/10 functions.
CC
U
, the constant-voltage mode and the timer is disabled
FUNCTIONS
U
U
TIMER
connected
GND (Pin 4): Ground.
PROG (Pin 5): Charge Current Program and Shutdown
Input Pin. The charge current is programmed by connect-
ing a resistor, R
= (V
into shutdown by floating the PROG pin and allowing the
internal 2.5 A current source to pull the pin above the
2.457V shutdown threshold voltage.
DRV (Pin 6): Drive Output Pin for the P-Channel MOSFET
or PNP Transistor. If a PNP transistor is used, it must have
high gain (see Applications Information section). The DRV
pin is internally clamped to 6.5V below V
V
to 12V when charging. If V
for example when the input supply is disconnected, then
the IC enters sleep mode with I
with a 1 F capacitor.
SENSE (Pin 8): Current Sense Input. Connect this pin to
the sense resistor. Choose the resistor value using the
following equation:
CC
R
PROG
(Pin 7): Input Supply Voltage. V
SENSE
• 800 )/(R
LTC1731-8.2/LTC1731-8.4
= (V
PROG
PROG
• 800 )/(R
PROG
to ground. The charge current is I
• R
CC
SENSE
drops below V
CC
PROG
< 30 A. Bypass this pin
). The IC can be forced
CC
• I
ranges from 8.8V
BAT
CC
)
.
BAT
sn1731 17318fs
+ 54mV,
5
BAT