Internal laser trimmed resistor networks set the gains for the IA and the DA, optimising the performance of the AD8451 over the rated temperature range. The IA gain is 26 and the DA gain is 0.8. Voltages at the I SET and V SET 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 logic level input, MODE, selects the charge or discharge mode (high for charge, low for discharge). An analog output, V CTRL, interfaces directly with Analog Devices’ ADP1972 PWM controller.
The AD8451 simplifies designs by providing accuracy, performance over temperature, flexibility with functionality, and overall reliability in a space-saving package. It comes in an 80-lead, 14 × 14 × 1 mm LQFP package and is rated for an operating temperature of −40°C to +85°C.
The device features;
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
Fixed gain settings
Excellent ac and dc performance
Maximum offset voltage drift of 0.9 μV/°C
Maximum gain drift of 3 ppm/°C
Current sense amplifier input voltage noise of under 9 nV/√Hz typ
Current sense CMRR of 108 dB minimum