Replacing the AD9764 with the GXSC DAC in Waveform Generators

In experimental testing scenarios, waveform generators convert digital waveform data into continuous analog waveforms. The system architecture consists of three major modules: the digital front end, the digital-to-analog converter (DAC), and the analog conditioning stage. The DAC coordinates with the other modules to achieve high-precision, multi-waveform generation. The high resolution of the DAC ensures waveform detail, while its high update rate supports the generation of high-frequency signals. Additionally, the chip’s low distortion, low power consumption, and high integration make it well-suited for the design requirements of portable and miniaturized waveform generators.

GXSC’s single-channel 14-bit 125 MSPS DAC can replace the AD9764 in waveform generators through hardware and software adaptation. The chip is manufactured using advanced CMOS technology and features a segmented current-source architecture; this manufacturing process not only reduces stray components but also enhances dynamic performance. It also integrates an edge-triggered input latch and a 1.25V temperature-compensated bandgap reference to provide a complete monolithic DAC solution. In practical applications, this combination of features is particularly well-suited for scenarios requiring high linearity, low distortion, and fast response.

The GXSC DAC features an on-chip reference and control amplifier to provide maximum accuracy and flexibility. It can be driven by the on-chip reference voltage or various external reference voltages. The internal control amplifier offers a wide adjustment range (>10:1), allowing the device’s full-scale current to be adjusted within the 2 mA to 20 mA range while maintaining excellent dynamic performance. Consequently, the GXSC DAC can operate at lower power levels and can be adjusted within a 20 dB range to provide additional gain variation.

GXSC DAC Product Advantages:

Packaged in a plastic TSSOP28, compatible with the AD9764.

Single-channel 125 MSPS 14-bit resolution DAC

Differential current output: 2 mA to 20 mA

Power consumption: 88 mW (@3.3 V)

Single 3.3 V supply

On-chip 1.25 V reference

Edge-triggered latch

Sampling Rate: 125 MSPS

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

Dynamic Performance

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

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

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

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

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