Analog Devices Inc. ADAR7251WBCSZ

Overview

ADAR7251WBCSZ from Analog Devices is a 4-channel, 16-bit simultaneous-sampling continuous-time Σ-Δ ADC optimized for automotive LSR-FMCW/FSK-FMCW radar front ends. It integrates LNA, PGA (45 dB gain range), equalizer, on-chip 1.5 V reference, and PLL with 16–54 MHz input clock support. At 1.2 MSPS, it delivers 94 dB SNR, 2.4 nV/√Hz input-referred noise at 45 dB gain, and −40°C to +125°C operation in a 48-lead LFCSP_SS package.

For engineers reviewing the ADAR7251WBCSZ datasheet, ADAR7251WBCSZ pinout, ADAR7251WBCSZ application, or ADAR7251WBCSZ equivalent, key selection criteria include channel-to-channel drift matching, FSK mode support for radar ramp synchronization, no external antialiasing filter requirement, and dual serial/parallel interface flexibility for DSP/MCU interfacing.

Technical Context

The ADAR7251WBCSZ implements four independent analog signal paths, each comprising a low-noise amplifier, programmable-gain amplifier with 6 dB step resolution, selectable equalizer (32–54 kHz corner), and multibit Σ-Δ modulator followed by decimation filtering. Its architecture eliminates need for external driver op amps or bipolar supplies while enabling direct MMIC interface.

It features an integrated PLL supporting 115.2 MHz internal clock generation from 16–54 MHz input, CONV_START/ DATA_READY timing control for precise FMCW ramp alignment, and configurable high-pass filter (0.73–93.3 Hz) plus auxiliary 8-bit ADC for system monitoring. All channels share synchronized sampling with <0.04° interchannel phase mismatch.

Key Specifications

Pinout & Package

ADAR7251WBCSZ uses a 48-lead 7 mm × 7 mm LFCSP_SS package with exposed thermal pad requiring soldering to PCB ground plane per JEDEC JESD51 standards (θJA = 25°C/W). Pin functions are validated per Analog Devices DS Rev. 0, Figure 7 and Table 9.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-channel, 16-bit radar ADC applications.

Compared with ADAR7251WBCSZ, ADAR7252WBCSZ offers identical radar interface functionality plus enhanced diagnostics, while ADS131M04IPBSR trades timing precision and RF bandwidth for DC accuracy-making ADAR7251WBCSZ the optimal balance of FMCW synchronization, noise performance, and automotive qualification.

Availability

ADAR7251WBCSZ is available at Aetrix Electronics and suitable for automotive radar modules, industrial condition monitoring systems, and medical ultrasound beamformers requiring stable component supply, long-term lifecycle assurance, and AEC-Q100-compliant sourcing.

Supply support for ADAR7251WBCSZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The ADAR7251WBCSZ belongs to Analog Devices' Automotive Radar Converter family, designed specifically to meet the signal integrity, timing coherence, and functional safety demands of LSR-FMCW radar systems in ADAS and autonomous driving platforms.

FAQ

What is the maximum input signal bandwidth supported by the ADAR7251WBCSZ at full 16-bit resolution?

The ADAR7251WBCSZ supports a 500 kHz input signal bandwidth at its maximum sample rate of 1.2 MSPS while maintaining 16-bit resolution and 94 dB SNR. This bandwidth is achieved without external antialiasing filters due to its integrated decimation filter with 70 dB stop-band attenuation at 800 kHz. Bandwidth scales with sample rate: 150 kHz at 300 kSPS and 900 kHz at 1.8 MSPS.

Does the ADAR7251WBCSZ require an external crystal oscillator, or can it operate with a single-ended clock input?

The ADAR7251WBCSZ supports both configurations: it can drive an external crystal between XIN (Pin 16) and XOUT (Pin 17), or accept a single-ended clock directly at XIN/MCLKIN (Pin 16). The PLL accepts input frequencies from 16 MHz to 54 MHz and generates a stable 115.2 MHz internal clock. No external crystal is mandatory - a clean 19.2 MHz master clock is commonly used in radar reference designs.

How does the ADAR7251WBCSZ handle channel-to-channel synchronization for FMCW radar applications?

The ADAR7251WBCSZ guarantees precise channel-to-channel synchronization via simultaneous sampling architecture and dedicated CONV_START and DATA_READY signals. Interchannel phase mismatch is limited to 0.04°, and gain mismatch to ±0.5 dB. The CONV_START input triggers all four ADCs simultaneously, while DATA_READY indicates valid data ready for readout - enabling deterministic timing alignment with radar chirp ramps in FSK-FMCW systems.

Can the ADAR7251WBCSZ interface directly with a TI C66x DSP without level-shifting circuitry?

Yes - the ADAR7251WBCSZ supports IOVDD1/IOVDD2 logic supplies at 3.3 V, matching the C66x DSP's EMIF I/O voltage. Its parallel PPI interface operates in byte-wide format with SCLK_ADC, FS_ADC, and ADC_DOUT[0:7] pins, allowing direct connection to the DSP's external memory interface. No level shifters are needed when both devices share the same 3.3 V I/O rail and proper decoupling is applied per Analog Devices layout guidelines.

What safety features does the ADAR7251WBCSZ provide for ASIL-B compliant automotive radar designs?

The ADAR7251WBCSZ includes CRC-protected register map access, ASIL error flag registers (ASIL Error Flag/Code), configurable error masking, and FAULT pin assertion on critical failures. Its register-level CRC calculation (enabled via dedicated control registers) validates configuration integrity, and the FAULT pin can be routed to MCU interrupt lines for real-time fault handling - collectively supporting ISO 26262 ASIL-B requirements without external safety monitors.