GXSC DAC Replaces AD9764 in Wireless Backhaul Equipment

Wireless backhaul equipment is a critical component for long-distance networking, enabling base station data relay and broadband long-distance transparent transmission through microwave line-of-sight links. It is widely used in scenarios such as 5G micro-base station backhaul, private power grid microwave links, wireless broadband coverage in remote areas, and UAV video transmission relay.

The high-speed parallel digital baseband signals output by wireless backhaul equipment are converted by a high-speed DAC into low-distortion, high-purity broadband intermediate-frequency analog signals. Traditional DAC solutions often use Analog Devices‘ AD9764. This proposal recommends the GXSC single-channel 14-bit 125MSPS digital-to-analog converter, which is a pin-to-pin compatible direct replacement for the AD9764.

The GXSC DAC delivers excellent AC and DC performance while supporting update rates up to 125MSPS. Manufactured with advanced CMOS process technology and a segmented current-source architecture, it reduces parasitic components and enhances dynamic performance, making it an ideal fit for signal conversion in communication base station transmit chains.

The GXSC DAC integrates an edge-triggered input latch and a 1.25V temperature-compensated bandgap reference to provide a complete monolithic DAC solution. Differential current outputs support both single-ended and differential applications. In differential output mode, matching between the two current outputs affects dynamic performance. The current outputs can be connected directly to output resistors to provide two complementary single-ended voltage outputs, or routed directly to a transformer.

GXSC DAC Product Advantages:

Pin-to-pin compatible with AD9764

Single-channel 125MSPS, 14-bit resolution DAC

Differential current output: 2mA to 20mA

Power consumption: 88mW (@3.3V)

Single 3.3V power supply

On-chip 1.25V reference

Edge-triggered latch

Sampling rate: 125MSPS

Package: Plastic TSSOP-28

Static performance: DNL -1.5/+1.5 LSB, INL -2.5/+2.5 LSB

Dynamic performance:

fclock = 25MSPS, fout = 1.00MHz, SFDR = 72dBc

fclock = 50MSPS, fout = 1.00MHz, SFDR = 65dBc

fclock = 50MSPS, fout = 2.51MHz, SFDR = 70dBc

fclock = 50MSPS, fout = 5.02MHz, SFDR = 74dBc

fclock = 50MSPS, fout = 20.2MHz, SFDR = 65dBc

The GXSC DAC‘s on-chip control amplifier provides a wide adjustment range (>10:1), allowing the full-scale current to be adjusted from 2mA to 20mA while maintaining excellent dynamic performance. As a result, the GXSC DAC can operate at lower power levels or be adjusted across a 20dB range to provide additional gain variation.