Analog Devices Inc. ADAU1797 Quad ADCs

Analog Devices ADAU1797 Quad ADCs combine four high-performance analog-to-digital converters (ADCs) with direct-coupled inputs capable of 10V_rms. The ADAU1797 implements multibit sigma-delta (Σ-Δ) architecture with a continuous time front end for low EMI. The devices can be directly connected to the electret microphone (ECM) and produce the bias for powering the microphone.

The ADI ADAU1797 Quad ADCs use only a single 3.3V supply. The part internally generates the microphone bias voltage. The microphone bias is programmable in a few steps from 5V to 9V. The low-power architecture reduces the power consumption. An on-chip PLL can derive the master clock from an external clock input or frame clock (sample rate clock). When fed with a frame clock, the PLL eliminates the requirement for a separate high-frequency master clock.

The ADAU1977 is housed in a 40-lead LFCSP package.

Features

Programmable microphone bias (5V to 9V) with diagnostics
4x 10V_rms capable direct-coupled differential inputs
On-chip PLL for master clock
Low EMI design
109dB ADC dynamic range
-95dB THD + N
Selectable digital high-pass filter
24-bit ADC with 8kHz to 192kHz sample rates

Digital volume control with auto ramp function
I²C/SPI control
Software-controllable clickless mute
Software power-down
Right justified, left justified, I²S justified, and TDM modes
Master and slave operation modes
40-lead LFCSP package
Qualified for automotive applications

Applications

Automotive audio systems
Active noise cancellation systems

Associated Eval Board

Analog Devices Inc. ADAU1797 Quad ADCs

Features

Applications

Block Diagram

Typical Application Schematic

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