MAX1908 Datasheet, PDF (1/27 Pages) Maxim Integrated Products – Low-Cost Multichemistry Battery Chargers

19-2764; Rev 2; 7/04
EVAALVUAAILTAIOBNLEKIT
Low-Cost Multichemistry Battery Chargers
General Description
The MAX1908/MAX8724 highly integrated, multichemistry
battery-charger control ICs simplify the construction of
accurate and efficient chargers. These devices use ana-
log inputs to control charge current and voltage, and can
be programmed by the host or hardwired. The MAX1908/
MAX8724 achieve high efficiency using a buck topology
with synchronous rectification.
The MAX1908/MAX8724 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 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 fea-
ture provides 300mA to safely charge deeply discharged
lithium-ion (Li+) battery packs.
The MAX1908 includes a conditioning charge feature
while the MAX8724 does not.
The MAX1908/MAX8724 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.
Applications
Notebook and Subnotebook Computers
Personal Digital Assistants
Hand-Held Terminals
Minimum Operating Circuit
AC ADAPTER
INPUT
0.01Ω
TO EXTERNAL
LOAD
LDO
FROM HOST µP
CSSP
DCIN
REFIN
CSSN
CELLS
LDO
VCTL
BST
ICTL
DLOV
ACIN
MAX1908
ACOK MAX8724 ^DHI
SHDN
LX
ICHG
DLO
IINP
PGND
CCV
CSIP
CCI
CCS
REF CLS
CSIN
BATT
GND
10µH
0.015Ω
BATT+
Features
♦ ±0.5% Output Voltage Accuracy Using Internal
Reference (0°C to +85°C)
♦ ±4% Accurate Input Current Limiting
♦ ±5% Accurate Charge Current
♦ Analog Inputs Control Charge Current and
Charge Voltage
♦ Outputs for Monitoring
Current Drawn from AC Adapter
Charging Current
AC Adapter Presence
♦ Up to 17.6V Battery-Voltage Set Point
♦ Maximum 28V Input Voltage
♦ >95% Efficiency
♦ Shutdown Control Input
♦ Charges Any Battery Chemistry
Li+, NiCd, NiMH, Lead Acid, etc.
PART
MAX1908ETI
MAX8724ETI
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 Thin QFN
28 Thin QFN
TOP VIEW
Pin Configuration
28 27 26 25 24 23 22
DCIN 1
LDO 2
CLS 3
REF 4
CCS 5
CCI 6
CCV 7
MAX1908
MAX8724
21 DLO
20 PGND
19 CSIP
18 CSIN
17 CELLS
16 BATT
15 VCTL
8 9 10 11 12 13 14
THIN QFN
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.