AD8450

Data Sheet Precision Analog Front End and Controller for Battery Test/Formation Systems AD8450 FEATURES GENERAL DESCRIPTION Integrated constant current and voltage modes with automatic switchover Charge and discharge modes Precision voltage and current measurement Integrated precision control feedback blocks Precision interface to PWM or linear power converters Programmable gain settings Current sense gains: 26, 66, 133, and 200 Voltage sense gains: 0.2, 0.27, 0.4, and 0.8 Programmable OVP and OCP fault detection Current sharing and balancing Excellent ac and dc performance Maximum offset voltage drift: 0.6 µV/°C Maximum gain drift: 3 ppm/°C Low current sense amplifier input voltage noise: ≤9 nV/√Hz Current sense CMRR: 126 dB minimum (gain = 200) TTL compliant logic The AD8450 is a precision analog front end and controller for testing and monitoring battery cells. A precision programmable gain instrumentation amplifier (PGIA) measures the battery charge/discharge current, and a programmable gain difference amplifier (PGDA) measures the battery voltage (see Figure 1). Internal laser trimmed resistor networks set the gains for the PGIA and the PGDA, optimizing the performance of the AD8450 over the rated temperature range. PGIA gains are 26, 66, 133, and 200. PGDA gains are 0.2, 0.27, 0.4, and 0.8. Voltages at the ISET and VSET inputs set the desired constant current (CC) and constant voltage (CV) values. CC to CV switching is automatic and transparent to the system. A TTL...