WM8770SIFT/RV

Overview

The WM8770SIFT/RV is a high-performance, multi-channel audio codec designed for surround sound processing in home hi-fi, automotive, and AV equipment. It features four independent stereo DACs with oversampling digital interpolation filters and a stereo 24-bit multi-bit sigma delta ADC with an eight-stereo channel input selector. The device supports digital audio output word lengths from 16 to 32 bits and sampling rates up to 192kHz for DAC and 96kHz for ADC. Audio performance includes 106dB SNR for the DAC and 102dB SNR for the ADC at 48kHz. It operates on 2.7V to 5.5V analogue and 2.7V to 3.6V digital supplies within a 64-lead TQFP package.

Feature Summary

• Four independent stereo DAC outputs with separate analogue and digital volume controls
• Eight stereo ADC inputs with programmable gain adjustment from +19dB to -12dB
• Support for I2S, left justified, and right justified digital audio formats
• Analogue bypass path allowing direct signal routing through volume controls

Applications

• Surround Sound AV Processors
• Home Hi-Fi Systems
• Automotive Audio

Procurement Notes

Verify the suffix RV indicates tape and reel packaging with a standard quantity of 750 units per reel. Confirm the Pb-free status and MSL3 moisture sensitivity level match project requirements. Ensure the operating temperature range of -40°C to +85°C is suitable for the target environment before finalizing procurement.

Selection Notes

Select this component when designing systems requiring eight discrete analogue inputs and four stereo DAC outputs. Verify that the master clock frequency supports the desired sample rate combinations, as the ADC and DAC can operate at different rates. Ensure the host controller supports the required 3-wire serial interface protocol for configuration.

Part Context

This part belongs to the Wolfson Microelectronics WM8770 series, specifically the SIFT variant housed in a 64-lead TQFP package. The RV suffix denotes the specific reel packaging format. The device is manufactured by Cirrus Logic Inc., following their acquisition of Wolfson Microelectronics.

Replacement Considerations

The WM8771FT/V serves as a functional substitute within the same family, offering identical pinout and core architecture. Verify that the replacement matches the specific voltage tolerances and package dimensions required for the existing PCB layout.

FAQ

Can the ADC and DAC operate at different sampling rates simultaneously?

Yes, the device allows the ADC and DAC to run at different sample rates, provided they share a common master clock.

What is the purpose of the analogue bypass path?

The analogue bypass path allows stereo signals from the ADC inputs to be routed directly to the DAC outputs via the main volume controls without digital conversion.

How are volume changes handled to prevent noise?

Zero-cross detect circuits are provided for both analogue and digital volume controls to minimize audible clicks and zipper noise during gain adjustments.