BQ25070 Datasheet, PDF (8/21 Pages) Texas Instruments – 1A, Single-Input, Single-Cell LiFePO4 Linear Battery Charger with 50mA LDO

bq25070
SLUSA66 – JULY 2011
PIN CONFIGURATION
(Top View)
www.ti.com
IN ₁
IMON 2
GND 3
LDO 4
TS 5
bq25070
10 _OUT
9 GND
8 CHG
7 CTRL
6 BAT
10 -pin 2mm x 3mm DFN
PIN
NAME
NO.
IN
1
IMON
2
GND
3, 9
LDO
4
TS
5
BAT
6
CTRL
7
CHG
8
OUT
10
Thermal
Pad
PAD
PIN FUNCTIONS
I/O
DESCRIPTION
I Input power supply. IN is connected to the external DC supply (AC adapter or USB port). Bypass IN to GND
with at least a 0.1μF ceramic capacitor.
O Current monitoring output. Connect a 1kΩ resistor from IMON to GND to monitor the input current. The
voltage at IMON ranges from 0V to 1V which corresponds to an input current from 0A to 1A.
– Ground terminal. Connect to the thermal pad and the ground plane of the circuit.
O LDO output. LDO is regulated to 4.9V and drives up to 50mA. Bypass LDO to GND with a 0.1μF ceramic
capacitor. LDO is enabled when V_UVLO < V_IN < V_OVP.
I Battery pack NTC monitoring input. Connect a resistor divider from LDO to GND with TS connected to the
center tap to set the charge temperature window. The battery pack NTC is connected in parallel with the
bottom resistor of the divider. See the Applications Design section for details on the selecting the proper
component values.
O Battery connection output. BAT is the sense input for the battery. Connect BAT and OUT to the battery and
bypass to GND with a 1μF ceramic capacitor.
I Single-input interface Input. Drive CTRL with pulses to enable/disable the device, enable/disable V_IN-DPM,
and select current limits. See the interface section for details on using the CTRL interface.
O Charge status indicator open-drain output. CHG is pulled low while the device is charging the battery. CHG
goes high impedance when the battery is fully charged.
O System output connection. Connect OUT and BAT together. Bypass the OUT and BAT connection to GND
with a 1μF ceramic capacitor.
– There is an internal electrical connection between the exposed thermal pad and the GND pin of the device.
The thermal pad must be connected to the same potential as the GND pin on the printed circuit board. Do not
use the thermal pad as the primary ground input for the device. GND pin must be connected to ground at all
times.
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