link to page 1 Low Cost, Precision Analog Front End andController for Battery Test/Formation SystemsData SheetAD8451FEATURESGENERAL DESCRIPTIONIntegrated constant current and voltage modes with The AD8451 is a precision analog front end and control er for automatic switchover testing and monitoring battery cells. A precision fixed gain Charge and discharge modes instrumentation amplifier (IA) measures the battery charge/ Precision voltage and current measurement discharge current, and a fixed gain difference amplifier (DA) Integrated precision control feedback blocks measures the battery voltage (see Figure 1). Internal laser Precision interface to PWM or linear power converters trimmed resistor networks set the gains for the IA and the DA, Fixed gain settings optimizing the performance of the AD8451 over the rated Current sense gain: 26 V/V (typ) temperature range. The IA gain is 26 V/V and the DA gain is Voltage sense gain: 0.8 V/V (typ) 0.8 V/V. Excellent ac and dc performance Voltages at the ISET and VSET inputs set the desired constant Maximum offset voltage drift: 0.9 µV/°C current (CC) and constant voltage (CV) values. CC to CV Maximum gain drift: 3 ppm/°C switching is automatic and transparent to the system. Low current sense amplifier input voltage noise: 9 nV/√Hz typ Current sense CMRR: 108 dB min A TTL logic level input, MODE, selects the charge or discharge TTL compliant logic mode (high for charge, and low for discharge). An analog output,