ADAR7251WBCSZ

Analog To Digital Converters (ADC) Overview

The ADAR7251WBCSZ is a 4-channel, 16-bit simultaneous sampling analog-to-digital converter (ADC) designed for automotive LSR-FMCW and FSK-FMCW radar systems. It features an integrated low noise amplifier (LNA), programmable gain amplifier (PGA), equalizer, multibit Σ-Δ ADC, and decimation filter. The device supports sample rates from 300 kSPS to 1.8 MSPS with an input signal bandwidth up to 900 kHz at 1.2 MSPS. It operates on a single 3.3 V supply with an internal 1.8 V digital core regulator. Key specifications include a maximum gain of 45 dB in 6 dB steps, an on-chip 1.5 V reference, and flexible serial or parallel data interfaces controlled via SPI.

Analog To Digital Converters (ADC) Feature Summary

• Integrated front-end circuitry including LNA, PGA, and equalizer allows direct connection to MMIC outputs without external driver op amps or high-order antialiasing filters.
• On-chip phase-locked loop (PLL) provides flexibility by accepting master clock frequencies between 16 MHz and 54 MHz.
• Supports FSK mode synchronization using CONV_START and DATA_READY signals for precise alignment with external ramps in radar applications.
• Offers selectable equalizer corner frequencies and precise channel-to-channel drift matching for accurate multi-channel data acquisition.

Analog To Digital Converters (ADC) Applications

• Automotive Low Side Range (LSR) radar systems
• FSK-FMCW radar systems
• General data acquisition systems

Analog To Digital Converters (ADC) Procurement Notes

Verify the specific suffix WBCSZ against the manufacturer's current ordering guide to confirm package type and temperature range variations. Ensure compatibility with automotive qualification standards if required for the target application. Cross-reference the datasheet revision to confirm all electrical parameters match the design requirements before finalizing procurement.

Analog To Digital Converters (ADC) Selection Notes

Select this component when designing automotive radar systems requiring simultaneous sampling of four channels with high dynamic range. Consider the internal PLL and flexible clock inputs if system timing constraints require specific master clock frequencies between 16 MHz and 54 MHz. Evaluate the need for the integrated LNA and PGA to simplify the analog front-end design and reduce external component count.

Analog To Digital Converters (ADC) Part Context

The ADAR7251 belongs to Analog Devices' family of continuous-time data acquisition ADCs tailored for radar applications. It replaces traditional architectures that require separate drivers, antialiasing filters, and bipolar supplies. The device integrates the complete signal chain from analog input to digital output, simplifying PCB layout and improving system reliability in harsh automotive environments.

Analog To Digital Converters (ADC) Replacement Considerations

No public confirmed substitute part numbers are available in the provided documentation. Designers should evaluate other 4-channel 16-bit SAR or Sigma-Delta ADCs from Analog Devices or competitors, ensuring they meet the specific bandwidth, sample rate, and automotive qualification requirements of the original design.

Analog To Digital Converters (ADC) FAQ

What is the purpose of the CONV_START and DATA_READY pins?

These pins synchronize the ADC conversion process with an external ramp signal, which is essential for applications such as FSK-FMCW radar systems to ensure precise timing alignment.

Can the ADAR7251 operate without an external crystal oscillator?

Yes, the device accepts a single-ended clock input at the XIN/MCLKIN pin. An external crystal is optional; the internal oscillator can be used if a suitable clock source is provided externally within the 16 MHz to 54 MHz range.

How does the ADAR7251 handle antialiasing filtering?

The device eliminates the need for a high-order external antialiasing filter due to its continuous-time input architecture and integrated digital decimation filter, which provides sufficient stop-band attenuation.