AD9975BST

Overview

The AD9975BST is a single-supply, broadband modem mixed-signal front end (MxFE) IC manufactured by Analog Devices Inc. It integrates a transmit path featuring a TxDAC+ with a 2× interpolation low-pass filter and a receive path comprising a programmable gain amplifier (PGA), a fourth-order low-pass filter (LPF), and a 10-bit ADC. The device operates on a 3.3 V supply and supports a DAC update rate of 100 MSPS with a 21 MHz transmit bandwidth. The receive ADC samples at 50 MSPS. Key specifications include a typical SNR of -56.6 dB for the receiver and -60.6 dB for the transmitter. It is housed in a 48-lead LQFP package and specified for commercial temperatures from –40°C to +85°C.

Feature Summary

• Integrated Transmit Path: Includes a 10-bit TxDAC+ with a digital 2× interpolation low-pass filter, supporting a 100 MSPS output update rate and 21 MHz bandwidth.
• Integrated Receive Path: Features a 10-bit multistage differential pipeline ADC, a dual-mode PGA with gain ranging from –6 dB to +36 dB, and a selectable cutoff LPF (12 MHz or 26 MHz).
• On-Chip Clock Generation: Contains a PLL clock multiplier that generates all required system clocks from a single crystal or clock input.
• Direct Interface Compatibility: Digital ports multiplex onto a 10-bit databus with individual clocks and enable lines, designed for direct connection to Homelug 1.0 PHY/MAC chips.

Applications

• Powerline Networking
• Home Phone Networking

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current guide. The provided datasheet lists the ABST variant; confirm if the BST suffix denotes an identical functional specification or a distinct revision. Ensure the component source provides valid traceability documentation consistent with Analog Devices quality standards.

Selection Notes

Select this component for broadband modem applications requiring integrated analog front-end conversion. Verify that the 10-bit resolution meets system dynamic range requirements. Confirm interface compatibility with downstream PHY/MAC controllers, specifically regarding the 10-bit data bus and clocking architecture. Check power consumption limits against available thermal dissipation capabilities in the 48-lead LQFP package.

Part Context

The AD9975 belongs to the MxFE family of mixed-signal converters designed for broadband communication systems. It consolidates functions typically requiring separate components, such as interpolation filtering, DAC/ADC conversion, and clock generation, into a single silicon die. This integration reduces board space and simplifies design complexity for networking applications.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Consult Analog Devices for current cross-reference information.