GXSC Digital-to-Analog Converter Replaces AD9764 for Software-Defined Radio Applications

Software-defined radio is a technology that implements wireless communication functions through software control of hardware platforms, offering flexibility and reconfigurability. It positions broadband analog-to-digital converters as close as possible to the RF antenna to digitize received analog signals at the earliest stage, enabling various radio functions through software. This approach allows radio equipment to adapt to different communication protocols and frequency bands via software updates and reconfiguration.

Within software-defined radio systems, the DAC converts the digital baseband signal output from the FPGA/DSP into an analog RF/IF signal. This requires a high-performance, low-power DAC. The GXSC single-channel 14-bit 125MSPS DAC is specifically designed for the transmit signal path in communication systems. It is ideally suited for applications in communication systems, base stations, ADSL/HFC modems, and similar domains. The chip supports update rates up to 125 MSPS, delivering exceptional dynamic performance and flexible power options.

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 either single-ended or differential applications. In differential output mode, the matching between the two current outputs affects dynamic performance. Current outputs can be directly connected to output resistors to provide two complementary single-ended voltage outputs, or output directly to a transformer.

Additionally, the GXSC DAC delivers exceptional dynamic performance: at a 125 MSPS sampling rate and 1 MHz output frequency, it achieves a spurious-free dynamic range (SFDR) of up to 80 dBc and total harmonic distortion (THD) as low as -70 dB. This effectively suppresses spurious signals and harmonic interference, ensuring signal purity. This capability is particularly crucial in software-defined radio scenarios involving multiple carriers and coexisting standards. It prevents spurious signals generated by the DAC from interfering with its own or adjacent communication links, enhancing the system‘s immunity to interference and safeguarding communication quality.

GXSC Digital-to-Analog Converter 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

Packaged in plastic TSSOP28