LP3945 Datasheet, PDF (2/15 Pages) National Semiconductor (TI) – Battery Charge Management System

LP3945/LP3946 LLP14 Package Drawing
20066503
(TOP VIEW)
See NS Package Number LDA14A
LP3945/LP3946 Pin Description
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LP3945
EN
SCL
SDA
BATT
V_BG
VB_SENSE
GND
Diff-Amp
BIPB
EOC
GND
CHG
StopModeEN
CHG-IN
LP3946
EN
GND
GND
BATT
V_BG
VB_SENSE
GND
Diff-Amp
BIPB
EOC
GND
CHG
StopModeEN
CHG-IN
Description
Charger Enable Input. Internally pulled high to CHG-IN pin.
Serial Interface Clock Input for LP3945. Ground in LP3946.
Serial Interface DATA Input/Output for LP3945. Ground in LP3946.
Battery supply input terminal. Must have 10 µF ceramic capacitor to GND.
Bandgap Voltage Reference (1.225V). Factory test point. Must be left floating.
Battery Voltage Sense connected to the + terminal of the battery.
Digital Ground
Charge current monitoring differential amplifier output. Voltage output representation
of the charge current.
Battery in Place Bar. Input signal to indicate presence/absence of the battery.
Internally pulled high to CHG-IN. Pulled low by the Battery ID resistor. Absence of
the ID resistor (BIPB signal high) indicates no battery. Pulling BIPB pin high sets the
device to LDO mode.
Active Low Open Drain Output to drive Green LED. Active when wall adaptor is
connected and battery is fully charged. Regardless of the battery chemistry, this
signal is available whenever a battery is attached.
Analog Ground
Active Low Open Drain Output to drive Red LED. Active when wall adaptor is
connected and battery is being charged. Regardless of the battery chemistry, this
signal is available whenever a battery is attached.
For normal operation, this pin must be left floating. Pulling this pin to ground will
bypass the 5.6 Hrs safety timer in constant current mode. See "StopModeEN PIN"
Section for more detail.
WARNING! Disabling the timer is not a recommended operating condition
since it disables the safety timer function. User must provide protection
against continuously charging a defective battery.
Charger input from a regulated, current limited power source. Must have a 1 µF
ceramic capacitor to GND.
Ordering Information
LP3945 supplied as 1000 units Tape and Reel
LP3945ILD
LP3946 supplied as 1000 units Tape and Reel
LP3946ILD
LP3945 supplied as 4500 units Tape and Reel
LP3945ILDX
LP3946 supplied as 4500 units Tape and Reel
LP3946ILDX
Package Marking
L00011B
Package Marking
L00030B
The LP3946 has default values of I_CHG=500mA, V_BATT=4.1V and EOC=0.1C. For other default options, please contact National
Semiconductor Sales Office.
www.national.com
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