19-1566; Rev 0a; 10/99
Advanced Chemistry-Independent, Level 2
Battery Charger with Input Current Limiting
General Description
The MAX1645 is a high-efficiency battery charger
capable of charging batteries of any chemistry type. It
uses the Intel System Management Bus (SMBus™) to
control voltage and current charge outputs.
When charging lithium-ion (Li+) batteries, the MAX1645
automatically transitions from regulating current to reg-
ulating voltage. The MAX1645 can also limit line input
current so as not to exceed a predetermined current
drawn from the DC source. A 175sec charge safety
timer prevents “runaway charging” should the
MAX1645 stop receiving charging voltage/current com-
mands.
The MAX1645 employs a next-generation synchronous
buck control circuitry that lowers the minimum input-to-
output voltage drop by allowing the duty cycle to
exceed 99%. The MAX1645 can easily charge one to
four series Li+ cells.
o
Input Current Limiting
o
175sec Charge Safety Timeout
o
128mA Wake-Up Charge
o
Charges Any Chemistry Battery:
Li+, NiCd, NiMH, Lead Acid, etc.
o
Intel SMBus 2-Wire Serial Interface
o
Compliant with Level 2 Smart Battery Charger
Spec. Rev. 1.0
o
+8V to +28V Input Voltage Range
o
Up to 18.4V Battery Voltage
o
11-Bit Battery Voltage Setting
o
±0.8% Output Voltage Accuracy with Internal
Reference
o
3A max Battery Charge Current
o
6-Bit Charge Current Setting
o
99.99% max Duty Cycle for Low-Dropout Operation
o
Load/Source Switchover Drivers
o
>97% Efficiency
Features
MAX1645
Applications
Notebook Computers
Point-of-Sale Terminals
Personal Digital Assistants
Pin Configuration
TOP VIEW
DCIN 1
LDO 2
CLS 3
REF 4
CCS 5
CCI 6
CCV 7
GND 8
BATT 9
DAC 10
V
DD
11
THM 12
SCL 13
SDA 14
28 CVS
27 PDS
26 CSSP
25 CSSN
24 BST
Ordering Information
PART
MAX1645EEI
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
28 QSOP
MAX1645
23 DHI
22 LX
21 DLOV
20 DLO
19 PGND
18 CSIP
17 CSIN
16 PDL
15 INT
Typical Operating Circuit appears at end of data sheet.
QSOP
SMBus is a trademark of Intel Corp.
________________________________________________________________
Maxim Integrated Products
1
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For small orders, phone 1-800-835-8769.
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