Replacing AD9268 with GX9268 Dual-Channel 16-Bit 125M ADC in IF Acquisition Boards

The IF acquisition board is the core front-end of modern digital receivers and software-defined radio systems. It converts the IF analog signal, downconverted by the RF front-end, into a digital signal for subsequent digital demodulation, spectrum analysis, and signal processing by the back-end DSP or FPGA.

Modern IF acquisition systems are placing increasingly higher demands on A/D conversion performance: on the one hand, IF signal frequencies continue to rise, requiring ADCs with high sampling rates and wide analog bandwidth; on the other hand, communication signals have a large dynamic range (covering received signals from -90 dBm to +10 dBm), requiring ADCs with high resolution and high SNR to simultaneously capture weak signals and strong signals without saturation distortion.

The GX9268 is a dual-channel, simultaneously sampling, 16-bit high-speed ADC that integrates two independent sampling channels on a single chip. The channels share the same clock source and are strictly synchronized, natively supporting direct I/Q quadrature IF sampling without the need for an external analog quadrature demodulator, thereby fundamentally eliminating the amplitude and phase errors introduced by analog quadrature demodulation. The advantages of the GX9268 are as follows:

Package size and function compatible with the AD9268

Low power consumption, no heat sink required

Optional on-chip dither

Programmable internal ADC voltage reference

Single 1.8V power supply

Flexible analog input range: 1 Vpp to 2 Vpp

Flexible power-saving/power-down modes

The GX9268 output data can be sent directly to two external 16-bit output ports, which can be configured as 1.8V CMOS or LVDS. When needed, flexible power-down options can significantly reduce power consumption. Programming for setup and control is accomplished through a three-wire SPI-compatible serial interface. Depending on application requirements and usage scenarios, the GX9268 is available in product families with different speed grades of 60M/80M/105M/125M, enabling flexible power consumption control, and the speed grade can be identified via a speed grade register.