LTC1732EMS-8.4 Linear Technology, LTC1732EMS-8.4 Datasheet - Page 10

• Manufacturer Part Number: LTC1732EMS-8.4
• Description: IC BATTCHRG CNTRLR LI-ION 10MSOP
• Manufacturer: Linear Technology

Specifications of LTC1732EMS-8.4

• Function: Charge Management
• Battery Type: Li-Ion, NiCd, NiMH
• Voltage - Supply: 4.5 V ~ 12 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: LTC1732EMS8.4

APPLICATIONS
LTC1732-8.4
Constant-Current Only Mode
The LTC1732-8.4 can be used as a programmable current
source by connecting the TIMER pin to V
particularly useful for charging NiMH or NiCd batteries. In
the constant-current only mode, the timer and voltage
amplifier are both disabled. An external termination method
is required to properly terminate the charge.
Battery Detection
The LTC1732-8.4 can detect the insertion of a new battery.
When a battery with voltage of less than 8.05V is inserted,
the LTC1732-8.4 resets the timer and a new charge cycle
begins. If the voltage of the new battery is above 8.05V, the
charging will not start if the TIMER has already timed out.
If a new battery (with a voltage above 8.05V) is inserted
while in the charging process, the timer will not be reset
and charging will continue until the timer runs out.
After a time out has occurred and the battery remains
connected, a new charge cycle will begin if the battery
voltage drops below 8.05V due to self-discharge or exter-
nal loading.
10
U
INFORMATION
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CC
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Many types of capacitors can be used for input bypassing.
However, caution must be exercised when using multi-
layer ceramic capacitors. Because of the self resonant and
high Q characteristics of some types of ceramic capaci-
tors, high voltage transients can be generated under some
start-up conditions, such as connecting the charger input
to a hot power source. To minimize these transients, only
ceramic capacitors with X5R or X7R dielectric are recom-
mended. Also, adding 1 or 2 in series with the ceramic
capacitor will further reduce these start-up transients. For
more information refer to Application Note 88.
Stability
The charger is stable without any compensation when a
P-channel MOSFET is used as the pass transistor.
However, a 10 F capacitor is recommended at the BAT
pin to keep the ripple voltage low when the battery is
disconnected.
If a PNP transistor is used for the pass transistor, a 1000pF
capacitor is required from the DRV pin to V
capacitor is needed to help stablize the voltage loop. A
10 F capacitor at the BAT pin is also recommended when
a battery is not present.
CC
Bypass Capacitor
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