Analog Devices ADAU1977

Description

The ADAU1977 incorporates four high performance analog-to-digital converters (ADCs) with direct-coupled inputs capable of 10 V rms. The ADC uses multibit sigma-delta (Σ-Δ) architecture with continuous time front end for low EMI. The ADCs can be connected to the electret microphone (ECM) directly and pro-vide the bias for powering the microphone. Built-in diagnostic circuitry detects faults on input lines and includes comprehensive diagnostics for faults on microphone inputs. The faults reported are short to battery, short to microphone bias, short to ground, short between positive and negative input pins, and open input terminals. In addition, each diagnostic fault is available as an IRQ flag for ease in system design. An I2C/SPI control port is also included. The ADAU1977 uses only a single 3.3 V supply. The part internally generates the microphone bias voltage. The microphone bias is programmable in a few steps from 5 V to 9 V. 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 need for a separate high frequency master clock in the system. The ADAU1977 is available in a 40-lead LFCSP package.

Features

• Programmable microphone bias (5 V to 9 V) with diagnostics
• Four 10 V rms capable direct-coupled differential inputs
• On-chip PLL for master clockLow EMI design
• 109 dB ADC dynamic range−95 dB THD + N
• Selectable digital high-pass filter24-bit ADC with 8 kHz to 192 kHz sample rates
• Digital volume control with autoramp 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

Table 12. Recommended InductorsRefer page no.22

Typical applications

• Active noise cancellation system
• Automotive audio systems

More information

• Datasheet
• IC product information