MAX8731A Datasheet, PDF (1/32 Pages) Maxim Integrated Products – SMBus Level 2 Battery Charger with Remote Sense

19-0756; Rev 0; 1/07
EVAALVUAAILTAIOBNLEKIT
SMBus Level 2 Battery Charger
with Remote Sense
General Description
The MAX8731A is an SMBus™ programmable multi-
chemistry battery charger. The MAX8731A uses a mini-
mal command set to easily program the charge voltage,
charge current, and adapter current limit.
The MAX8731A charges one to four Li+ series cells and
delivers up to 8A charge current. The MAX8731A drives
n-channel MOSFETs for improved efficiency and
reduced cost. Low-offset current-sense amplifiers pro-
vide high accuracy with 10mΩ sense resistors.
The MAX8731A current-sense amplifiers provide high
accuracy (3% at 3.5A) and also provide fast cycle-by-
cycle current-mode control to protect against battery
short circuit and system load transients.
The charger employs dual remote sense, which reduces
charge time by measuring the feedback voltage directly
at the battery, improving accuracy of initial transition into
constant-voltage mode. The MAX8731A provides 0.5%
battery voltage accuracy directly at the battery terminal.
The MAX8731A provides a digital output that indicates
the presence of the AC adapter, as well as an analog out-
put that indicates the adapter current within 4% accuracy.
The MAX8731A is available in a small 5mm x 5mm,
28-pin, thin (0.8mm) QFN package. An evaluation kit is
available to reduce design time. The MAX8731A is avail-
able in a lead-free package.
SMBus is a trademark of Intel Corp.
Applications
Notebook Computers
Tablet PCs
Medical Devices
Portable Equipment with Rechargeable Batteries
Pin Configuration
TOP VIEW
21 20 19 18 17 16 15
DCIN 22
LX 23
DHI 24
BST 25
V_CC 26
CSSN 27
CSSP 28
MAX8731A
*EXPOSED PADDLE
14 BATSEL
13 ACOK
12 GND
11 VDD
10 SCL
9 SDA
8 IINP
1 234567
Features
♦ 0.5% Battery Voltage Accuracy
♦ 3% Input Current-Limit Accuracy
♦ 3% Charge-Current Accuracy
♦ SMBus 2-Wire Serial Interface
♦ Cycle-by-Cycle Current Limit
Battery Short-Circuit Protection
Fast Response for Pulse Charging
Fast System-Load-Transient Response
♦ Dual-Remote-Sense Inputs
♦ Monitor Outputs for
Adapter Current (4% Accuracy)
AC Adapter Detection
♦ 11-Bit Battery Voltage Setting
♦ 6-Bit Charge-Current/Input-Current Setting
♦ 8A (max) Battery Charger Current
♦ 11A (max) Input Current
♦ +8V to +26V Input Voltage Range
♦ Charges Li+, NiMH, and NiCd Battery Chemistries
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
PKG
CODE
MAX8731AETI+
-40°C to +85°C
28 Thin QFN
(5mm x 5mm)
T2855-6
+Indicates a lead-free package.
Typical Operating Circuit
OPTIONAL
HOST
SCL
SDA
VDD
CSSP
ACIN
DCIN
ACOK
CSSN
DHI
LX
MAX8731A DLO
REF
PGND
BST
CSIP
GND
CSIN
BATSEL
FBSA
SCL
SDA
FBSB
VDD
GND
LDO
VCC
IINP
CCV
DAC CCS CCI
EXTERNAL LOAD
N
N
SELECTOR
BATSEL
BATTERY
A
BATTERY
B
THIN QFN
5mm x 5mm
________________________________________________________________ Maxim Integrated Products 1
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