Circuit Note CN-0237 is a reference circuit for Analog Devices' ultralow power, low distortion differential ADC driver ADA4940-1/ADA4940-2, 18-bit, 1 MSPS PulSAR ADC AD7982 and 5 V precision bandgap voltage reference ADR395 to help solve today's analog, mixed-signal and RF design challenges.
This document presents Circuit Note CN-0237, a reference design for driving an ultralow power 18-bit differential ADC. The circuit utilizes the ADA4940-1 fully differential amplifier to drive the AD7982 PulSAR ADC, powered by an ADR395 voltage reference.
The design achieves high performance with a Signal-to-Noise Ratio (SNR) of 95.06 dBFS and Spurious-Free Dynamic Range (SFDR) of 105.02 dBFS at 1 MSPS sampling rate. The total power dissipation for the system is less than 17 mW, making it suitable for low-power applications.
The total power dissipated by the system is less than 17 mW.
The single-ended input impedance is approximately 1.33 kΩ.
The differential input impedance is 2 kΩ.