MAX1873 Maxim, MAX1873 Datasheet - Page 8

• Manufacturer Part Number: MAX1873
• Description: Simple Current-Limited Switch-Mode Li Charger Controller
• Manufacturer: Maxim

Simple Current-Limited Switch-Mode
Li+ Charger Controller
8
PIN
10
11
12
13
14
15
16
_______________________________________________________________________________________
1
2
3
4
5
6
7
8
9
ICHG/EN
NAME
CSSN
CSSP
VADJ
IOUT
BATT
DCIN
GND
CCS
CCV
CSB
REF
CCI
EXT
VH
VL
Source Current-Sense Negative Input. Connect a current-sense resistor between CSSP and CSSN to
limit total current drawn from the input source. To disable input current sensing, connect CSSN to CSSP.
Battery Regulation Voltage Control-Loop Compensation Point. Pulling CCV high (to VL) through a 1.5kΩ
resistor disables the voltage control loop for charging NiCd or NiMH batteries.
Battery Charge Current Control-Loop Compensation Point
Battery Charging Current Adjust/Shutdown Input. This pin can be connected to a resistive-divider
between REF and GND to adjust the charge current sense threshold between CSB and BATT. When
ICHG/EN is connected to REF, the CSB-BATT threshold is 200mV. Pull ICHG/EN low (below 500mV) to
disable charging and reduce the supply current to 5µA.
Charge Current Monitor Output. Analog Voltage Output that is proportional to charging current. V
= 20 (V
Battery Regulation Voltage Adjust. Set the battery regulation voltage from 3.979V per cell to 4.421V per
cell with 1% resistors. Output accuracy remains better than 0.75% even with 1% adjusting resistors
due to reduced adjustment range. For 4.2V, the voltage-divider resistors must be equal value
(nominally 100kΩ each).
Battery Voltage-Sense Input and Battery Current-Sense Negative Input. Bypass to GND with a 68µF for
MAX1873R, 47µF for MAX1873S, and 33µF for MAX1873T. Use capacitors with ESR < 1Ω.
Battery Current-Sense Positive Input
Ground
Internal VH Regulator. VH internally supplies power to the EXT driver. Connect a 0.22µF ceramic
capacitor between VH and DCIN.
Drive Output for External PFET. EXT swings from V
Power-Supply Input. DCIN is the input supply for charger IC. Bypass to GND with a 0.22µF ceramic
capacitor.
Internal VL Regulator. VL powers the MAX1873’s control logic at 5.4V. Bypass to GND with a 2.2µF or
larger ceramic capacitor.
Source Current-Sense Positive Input. Also used for input source undervoltage sensing.
Input-Source-Current Regulation Loop Compensation Point
4.2V Reference Voltage Output. Bypass to GND with a 1µF ceramic capacitor.
CSB
- V
BATT
) or 4V for a 200mV current-sense voltage (maximum load capacitance = 5nF).
FUNCTION
DCIN
to V
DCIN
- 5V.
Pin Description
IOUT