ADI AD8450ASTZ

The AD8450 is a precision analog front end and controller for battery test and monitoring applications. A precision programmable gain instrumentation amplifier (PGIA) measures battery charge/discharge current, while a programmable gain differential amplifier (PGDA) measures battery voltage. Internal laser-trimmed resistor networks set the gains of the PGIA and PGDA, optimizing AD8450 performance 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 applied to the ISET and VSET inputs set the desired constant current (CC) and constant voltage (CV). Automatic seamless CC-to-CV transition is provided. The MODE pin (TTL logic level) selects charge or discharge mode (high = charge, low = discharge). The analog output VCTRL interfaces directly with ADI's ADP1972 PWM controller. The AD8450 integrates resistor-programmable overvoltage and overcurrent detection along with current sharing circuitry. Current sharing is used to balance charge across multiple batteries. The AD8450 simplifies design by delivering excellent accuracy, performance (over the full temperature range), flexible functionality, and overall reliability, all in a space-saving package. The AD8450 is available in an 80-lead, 14 mm × 14 mm × 1 mm LQFP package and is rated for an operating temperature range of −40°C to +85°C.

• Integrated CC and CV mode with auto-switching
• Charge and discharge modes
• Precision voltage and current measurement
• Integrated precision control feedback module
• Precision interface for PWM or linear power converters
• Programmable gain settings: current sense gains of 26, 66, 133, and 200; voltage sense gains of 0.2, 0.27, 0.4, and 0.8
• Programmable OVP and OCP fault detection
• Current sharing and current 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 logic compatible

• Battery formation and testing
• Battery module testing