The MAX8845Z/MAX8845Y are intelligent, stand-alone
constant-current, constant-voltage (CCCV), thermally
regulated linear chargers designed for charging a single-cell lithium-ion (Li+) battery. The MAX8845Z/MAX8845Y integrate a current-sense circuit, MOSFET
pass element, thermal-regulation circuitry, and eliminate
the external reverse-blocking Schottky diode to
create the simplest and smallest charging solutions for
handheld equipment.
The ICs control the charging sequence from the pre-qualification
state through constant current fast-charge,
top-off charge, and full-charge indication. Proprietary
thermal-regulation circuitry limits the die temperature
during fast-charging or when the ICs are exposed to
high ambient temperatures, allowing maximum charging
current without damaging the ICs.
The MAX8845Z/MAX8845Y achieve high flexibility
by providing adjustable fast-charge currents
(SETI) and an adjustable top-off current threshold
(MIN) through external resistors. The MAX8845Z/MAX8845Y feature a booting assistant circuit that distinguishes
input sources and battery connection and
provides an enable signal (ABO—MAX8845Z and
active-low ABO—MAX8845Y) for system booting.
The MAX8845Z/MAX8845Y also integrate an overvoltage-protected output (SAFEOUT) for low voltage-rated
USB or charger inputs in system, and a battery-pack
detection circuit (DETBAT) that disables the charger
when the battery pack is absent. Other features include
an active-low control input (active-low EN), an active-low input
power source detection output (active-low POK), and a fully
charged top-off threshold detection output (active-low CHG).
The MAX8845Z/MAX8845Y accept an input supply
range from 4.25V to 28V, but disable charging if the
supply voltage exceeds +7.5V to protect against
unqualified or faulty AC adapters. The ICs operate over
the extended temperature range (-40°C to +85°C) and
are available in a compact 12-pin, thermally enhanced
thin QFN, 3mm x 3mm package (0.8mm max height).
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