GXSC ADC Replacement of AD9694 for Low-Altitude Surveillance Radar

Low-altitude surveillance radar typically employs X/S-band frequency modulation, transmitting high-frequency detection electromagnetic waves through antenna arrays. The radar receiving antenna and RF front-end perform low-noise amplification, frequency mixing and down-conversion, and IF conditioning, outputting wideband IF analog echo signals. A high-speed ADC acquisition front-end then completes high-precision analog-to-digital conversion, transforming the continuous echo waveforms into discrete digital signals.

GXSC‘s four-channel 14-bit 500MSPS analog-to-digital converter, featuring a 1.4GHz full-power analog bandwidth, integrates multi-channel simultaneous sampling and an on-chip digitally controlled oscillator with programmable filtering. It serves as a high-precision acquisition chip for the digital front-end of low-altitude surveillance radar, effectively addressing issues such as weak signal submersion and insufficient bandwidth in low-altitude radar applications. The GXSC ADC is both hardware- and software-compatible with the AD9694, supporting direct drop-in replacement on existing boards.

The GXSC ADC integrates output error correction logic, with each ADC featuring wideband input that supports various user-selectable input ranges. Both analog inputs and clock signals are differential inputs. ADC data outputs are routed through an internal multiplexer to four Digital Down-Converters (DDCs). Each DDC consists of multiple cascaded signal processing stages, including a 48-bit frequency translator (Numerically Controlled Oscillator) and up to four half-band decimation filters. Switching between DDC modes is programmable via SPI.

GXSC ADC Product Advantages:

1. Package dimensions are compatible with the reference model, supporting drop-in replacement of the AD9694

2. Power consumption is approximately 53% of the reference chip, effectively reducing overall system power dissipation

3. Wider operating temperature range of -55°C to +125°C, offering better environmental adaptability

4. Compact package size, effectively reducing system footprint

5. High integration level with integrated digital down-conversion and filters, helping to lower system costs

6. JESD204B high-speed interface, facilitating user layout and routing

The chip features an on-chip buffer and sample/hold circuits designed for low power, small size, and ease of use. The device delivers a -3dB input bandwidth of 1.4GHz, with power consumption approximately 53% of the reference chip, effectively reducing overall system power dissipation. It offers advantages including high sampling rate, excellent linearity, compact packaging, and low power consumption.