Analog Devices Inc. AD4085 Low-Noise Low-Power SAR ADC
Analog Devices AD4085 Low-Noise Low-Power SAR Analog-to-Digital Converter (ADC) is a high-speed, low-noise, low-distortion, 16-bit, Easy Drive, successive approximation register (SAR) ADC. Maintaining high performance (signal-to-noise and distortion (SINAD) ratio > 92dBFS) at signal frequencies exceeding 1MHz enables the AD4085 to serve a wide variety of precision, wide-bandwidth data-acquisition applications. Oversampling combined with integrated digital filtering and decimation reduces noise, lowers the output data rate, and simplifies the design of the input anti-alias filter.
The AD4085 Easy Drive features reduce both signal-chain complexity and power consumption while enabling greater channel density and greater flexibility in companion-component selection. A specialized input structure minimizes input-dependent signal currents, thereby reducing converter-induced settling artifacts. The continuous acquisition architecture allows settling across the entire conversion cycle, easing ADC driver settling and bandwidth requirements as compared to other high-speed data converters.
The Analog Devices AD4085 includes several elements that simplify data converter integration: a low-drift reference buffer, low-dropout (LDO) regulators to generate the ADC core and digital interface supply rails, and a 16K result-first-in-first-out (FIFO) that can greatly reduce the load on the digital host. Additionally, critical supply and reference decoupling capacitors are integrated in the package to ensure optimum performance, simplify printed circuit board (PCB) layout, and reduce the overall solution footprint.
Features
- 16-bit resolution, no missing codes
- 10MSPS thoughput with 131.25ns conversion latency
- 20.85nV/√Hz, -160.1dBFS/Hz noise spectral density
- 206.4nVrms low 1/f, low frequency noise (0.1Hz to 10Hz)
- 57.8mW (typ.) at 10MSPS low power
- ±5ppm (typ.), ±10ppm (max.) INL
- 93.2dBFS dynamic range
- SNR/THD
- 92.9dB (typ.)/-114.5dB (typ.) at fIN = 1kHz
- 92.5dB (typ.)/-102.9dB (typ.) at fIN = 1MHz
- Easy Drive
- 6Vp-p differential input range
- Continuous signal acquisition
- Linearized, 5μA/MSPS input current
- Integrated, low-drift reference buffer and decoupling
- Integrated VCM generation
- Digital features and data interface
- Conversion result FIFO, 16K sample depth
- Digital averaging filter with up to 210 decimation
- SPI configuration
- Configurable data interface
- Single lane, DDR, serial LVDS, 160Mbps per lane
- Dual lane, DDR, serial LVDS, 80Mbps per lane
- Single/quad lane SPI data interface
- Package
- 49-ball, 5mm × 5mm CSP_BGA, 0.65mm pitch
- Integrated supply decoupling capacitors
- -40°C to +85°C operating temperature range
Applications
- Digital imaging
- Cell analysis
- Spectroscopy
- Automated test equipment
- High-speed data acquisition
- Digital control loops, hardware in the loop
- Power quality analysis
- Source measurement units
- Electron and X-ray microscopy
- Radar level measurement
- Nondestructive test
Functional Block Diagram
