ltc1730es8-4.2-trpbf Linear Technology Corporation, ltc1730es8-4.2-trpbf Datasheet
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ltc1730es8-4.2-trpbf
Manufacturer Part Number
ltc1730es8-4.2-trpbf
Description
Lithium-ion Battery Pulse Chargers With Overcurrent Protection
Manufacturer
Linear Technology Corporation
Datasheet
1.LTC1730ES8-4.2-TRPBF.pdf
(12 pages)
FEATURES
APPLICATIO S
TYPICAL APPLICATIO
Complete Pulse Charger for 1-Cell Lithium-Ion
Batteries
Sense Resistor Limits Maximum Current for Safety
1% Float Voltage Accuracy
End-of-Charge (C/10) Detection Output
Programmable Charge Termination Timer
Internal 0.35 NMOS Switch
No Blocking Diode Required
SEL Pin to Set Either 4.1V or 4.2V/Cell (LTC1730-4)
Low-Battery Drain (1 A Max) when Input Supply Is
Removed
Battery Temperature Sensing and Charge
Qualification
Automatic Trickle Charge for Low-Battery
Automatic Battery Refresh
Standalone Lithium-Ion Battery Charger
Handheld Computers
Cellular Telephones
U
*NTC: DALE NTHS-1206N02
WITH 1A CURRENT LIMIT
V
1A, Single Cell 4.2V Li-Ion Battery Charger (8-Pin Package)
IN
CHARGE STATUS
U
= 4.5V TO 12V
T
R3
4.1k
R4
10k
NTC*
D3
R1
1k
C
TIMER
0.1 F
3
6
CHRG
NTC/SHDN
TIMER
LTC1730ES8-4.2
5
V
DESCRIPTIO
The LTC
lithium-ion batteries. When charging a depleted cell, the
internal MOSFET is fully on allowing the current limited
input power source to provide charge current to the
battery, virtually eliminating heat generation in the charger.
As the battery accepts charge and approaches the pro-
grammed voltage, the internal MOSFET begins switching
off and on with the duty cycle gradually decreasing as the
battery approaches a fully charged condition. A program-
mable timer ends the charge cycle. The end-of-charge
condition is indicated at the CHRG pin when the average
charge current falls to C/10. Removing the input voltage
puts the LTC1730 into a sleep mode, dropping the battery
current drain to less than 1 A (maximum).
An external sense resistor limits the maximum charge
current as a safety precaution against a user connecting a
wall adapter with the incorrect or no current limit. The
internal MOSFET prevents reverse battery current from
flowing if the input voltage is shorted to ground, eliminat-
ing the need for a blocking diode.
The LTC1730-4 is available in the 16-pin SSOP package
and the LTC1730-4.2 is available in the 8-pin SO package.
CC
2
SENSE
GND
, LTC and LT are registered trademarks of Linear Technology Corporation.
GATE
BAT
4
7
1
8
Overcurrent Protection
LTC1730-4/LTC1730-4.2
®
1730 is a complete pulse charger for 1-cell
R2
10k
1-CELL
Li-Ion
BATTERY
C3
0.047 F
0.022 F
Pulse Charger with
Lithium-Ion Battery
R
0.05
SENSE
U
1730 TA01
4.7
C1
1 F
sn1730 1730fs
1