Rorebai High-Speed ADCs

Pipelined ADCs and SAR ADCs have different architectures suited for different applications: (1) Pipelined ADCs - use multiple stages operating in parallel to achieve high sampling rates (100MSPS to GSPS), ideal for communications and wideband applications

(2) SAR ADCs - use successive approximation for high resolution (16-24 bits) at moderate speeds (up to 10MSPS), ideal for precision measurement and industrial applications. Rorebai offers both types: CBM94xxx series pipelined ADCs for high-speed applications and CBM92xxx series SAR ADCs for precision applications. Choose pipelined for speed, SAR for resolution.

Choose pipelined ADCs for high-speed applications; choose SAR ADCs for high-resolution precision measurement.

ADC dynamic performance is characterized by several key parameters: (1) SNR (Signal-to-Noise Ratio) - measures signal quality relative to noise floor, higher is better

(2) SFDR (Spurious-Free Dynamic Range) - measures distortion products relative to fundamental, higher is better

(3) ENOB (Effective Number of Bits) - actual resolution considering noise and distortion

(4) THD (Total Harmonic Distortion) - measures harmonic distortion

(5) SINAD (Signal-to-Noise and Distortion) - combines SNR and THD. For communications, SFDR > 70dBc and SNR > 65dBFS are typically required. Rorebai ADCs provide detailed dynamic performance specifications in their datasheets.

Evaluate ADCs based on SNR, SFDR, and ENOB for your specific application requirements.

Rorebai high-speed ADCs have specific input drive requirements: (1) Input impedance - typically 50Ω differential or 1kΩ single-ended

(2) Input range - varies by model, commonly 1Vpp to 2Vpp differential

(3) Bandwidth - driver amplifier should have bandwidth > 2x ADC sampling rate

(4) Noise - driver noise should be well below ADC noise floor

(5) Distortion - driver THD should be better than ADC specification. Rorebai provides recommended driver amplifiers and reference circuits in their datasheets. For best performance, use differential signaling and proper termination.

Use recommended driver amplifiers with adequate bandwidth and low noise for optimal ADC performance.

Rorebai ADCs support multiple digital interfaces: (1) LVDS - low-voltage differential signaling for high-speed data transfer, most common for high-speed ADCs

(2) CMOS - single-ended interface for lower speed applications

(3) JESD204B/C - high-speed serial interface for very high sampling rates

(4) SPI - for configuration and control registers. Interface selection depends on sampling rate and system requirements. Rorebai ADCs typically use LVDS for data output and SPI for configuration. Reference designs and FPGA interface examples are available from LiTong.

Use LVDS for high-speed data, SPI for configuration; JESD204 for very high sampling rates.

High-speed ADC clocking requirements: (1) Clock jitter - sampling clock jitter directly impacts SNR, use low-jitter clock sources (<1ps RMS)

(2) Clock frequency - must match ADC sampling rate requirements

(3) Clock amplitude - typically LVDS or LVPECL levels

(4) Duty cycle - 50% duty cycle required for optimal performance

(5) Clock distribution - use proper clock buffers for multiple ADCs. Rorebai ADCs provide clock input specifications in their datasheets. For multi-channel systems, use clock distribution chips to ensure phase alignment. Contact LiTong FAE for clocking design support.

Use low-jitter clock sources and proper clock distribution for optimal ADC performance.