Data Sheet

MAX17043/MAX17044
Compact, Low-Cost 1S/2S Fuel Gauges
with Low-Battery Alert
10 ______________________________________________________________________________________
Figure 6 shows an example application for a 1S cell
pack. The MAX17043 is mounted on the system side
and powered directly from the cell pack. The external
RC networks on V
DD
and CELL provide noise filtering of
the IC power supply and A/D measurement. In this
example, the ALRT pin is connected to the micro-
processor's interrupt input to allow the MAX17043 to
signal when the battery is low. The QSTRT pin is
unused in this application, so it is tied to GND.
Figure 7 shows a MAX17044 example application using
a 2S cell pack. The MAX17044 is mounted on the sys-
tem side and powered from a 3.3V supply generated
by the system. The CELL pin is still connected directly
to PACK+ through an external noise filter. The ALRT pin
is left unconnected because the interrupt feature is not
used in this application. After power is supplied, the
system watchdog generates a low-to-high transition on
the QSTRT pin to signal the MAX17044 to perform a
quick-start.
PACK-
PACK+
PROTECTION IC
(Li+/POLYMER)
SYSTEM GND
SYSTEM V
DD
BATTERY SYSTEM
MAX17043
CELL
EP
1µF
1kΩ
10nF
150Ω
GND
CTG
SCL
SDA
QSTRT
V
DD
ALRT
SYSTEM µP
I
2
C BUS
MASTER
INTERRUPT
INPUT
4.7kΩ
Figure 6. MAX17043 Application Example with Alert Interrupt
PACK-
PACK+
PROTECTION IC
(Li+/POLYMER)
SYSTEM GND
SYSTEM V
DD
BATTERY SYSTEM
MAX17044
CELL
1µF
1kΩ
GND
CTG SCL
SDA
QSTRT
V
DD
SYSTEM PMIC
SYSTEM µP
I
2
C BUS
MASTER
3.3V OUTPUT
WATCHDOG
ALRT
EP
Figure 7. MAX17044 Application Example with Hardware Reset