The MAX8672 evaluation kit (EV kit) is a fully assembled
and tested PCB that evaluates the MAX8672 backup-management
IC for NiMH batteries. The MAX8672 EV kit
charges one- or two-cell NiMH batteries, with the EV kit
configured for two-cell applications. Maximum battery-charge
voltage, standard-charge current, and trickle-charge
current are preprogrammed to 3V, 3mA, and
450µA, respectively, using external resistors. The programmable
charge timer is set to 480 minutes. An
adjustable battery undervoltage-lockout (UVLO) threshold
is preset to 1.6V and shuts down battery-backup
functions.
To support system-supply voltages, the MAX8672 EV
kit provides two outputs. Low-voltage backup cells are
stepped up to a fixed 3.05V by a low quiescent-current
synchronous-rectified step-up DC-DC converter capable
of delivering up to 20mA. A low-dropout (LDO) output
is set to 1.75V and is capable of providing up to
20mA. The LDO output voltage is adjustable with external
resistors.
The MAX8672 EV kit also features a thermistor input to
monitor battery temperature (negative temperature
coefficient (NTC) thermistor not included). To simulate a
100kΩ thermistor at TA = +25°C, the EV kit comes with a 100kΩ resistor installed. See the Thermistor Monitor
section for details.
The MAX8672 EV kit comes fully assembled and tested
and has an operating temperature range of -40°C to
+85°C.