Document
19-2764; Rev 5; 11/09
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Low-Cost Multichemistry Battery Chargers
General Description
The MAX1908/MAX8724/MAX8765/MAX8765A highly integrated, multichemistry battery-charger control ICs simplify the construction of accurate and efficient chargers. These devices use analog inputs to control charge current and voltage, and can be programmed by the host or hardwired. The MAX1908/MAX8724/MAX8765/ MAX8765A achieve high efficiency using a buck topology with synchronous rectification. The MAX1908/MAX8724/MAX8765/MAX8765A feature input current limiting. This feature reduces battery charge current when the input current limit is reached to avoid overloading the AC adapter when supplying the load and the battery charger simultaneously. The MAX1908/MAX8724/MAX8765/MAX8765A provide outputs to monitor current drawn from the AC adapter (DC input source), battery-charging current, and the presence of an AC adapter. The MAX1908’s conditioning charge feature provides 300mA to safely charge deeply discharged lithium-ion (Li+) battery packs. The MAX1908 includes a conditioning charge feature while the MAX8724/MAX8765/MAX8765A do not. The MAX1908/MAX8724/MAX8765/MAX8765A charge two to four series Li+ cells, providing more than 5A, and are available in a space-saving, 28-pin, thin QFN package (5mm × 5mm). An evaluation kit is available to speed designs.
Features
o ±0.5% Output Voltage Accuracy Using Internal Reference (±0.4% for MAX8765A, 2-/3-Cell Only) o ±4% Accurate Input Current Limiting o ±5% Accurate Charge Current o Analog Inputs Control Charge Current and Charge Voltage o Outputs for Monitoring Current Drawn from AC Adapter Charging Current AC Adapter Presence o Up to 17.6V Battery-Voltage Set Point o Maximum 28V Input Voltage o > 95% Efficiency o Shutdown Control Input o Charge Any Battery Chemistry Li+, NiCd, NiMH, Lead Acid, etc.
MAX1908/MAX8724/MAX8765/MAX8765A
Ordering Information
PART MAX1908ETI+ MAX8724ETI+ MAX8765ETI+ MAX8765AETI+ TEMP RANGE -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C PIN-PACKAGE 28 Thin QFN-EP* 28 Thin QFN-EP* 28 Thin QFN-EP* 28 Thin QFN-EP*
Applications
Notebook and Subnotebook Computers Personal Digital Assistants Handheld Terminals
Minimum Operating Circuit
AC ADAPTER INPUT 0.01Ω TO EXTERNAL LOAD
+Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad.
Pin Configuration
TOP VIEW
CELLS PGND VCTL 15 14 13 12
GND ICTL
CELLS DCIN REFIN VCTL ICTL ACIN ACOK FROM HOST µP SHDN ICHG IINP CCV CCI CCS REF CLS CSIN BATT GND BST DLOV LDO
21
DLOV LX
DHI LX
20 19
18
17
16
LDO
22 23 24 25 26 27 28
MAX1908 MAX8724 MAX8765 MAX8765A
BST DHI
BATT
CSSP
CSSN
CSIN
CSIP
DLO
REFIN ACOK
ACIN
DLO 10µH PGND
CSSN
CSSP
CSIP 0.015Ω
MAX1908 MAX8724 MAX8765 MAX8765A
11 10 9 8
ICHG SHDN
IINP
BATT+
+
1 DCIN
2 LDO
3 CLS
4 REF
5 CCS
6 CCI
7 CCV
THIN QFN
________________________________________________________________ Maxim Integrated Products
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