Analog Devices Inc. AD4851 250kSPS Data Acquisition System (DAS)
Analog Devices AD4851 250kSPS Data Acquisition System (DAS) is a fully buffered, four‑channel, simultaneous‑sampling 16‑bit DAS capable of operating at 250kSPS, featuring differential inputs with a wide common‑mode range. Designed to run from a low 5V supply and to support flexible input buffer supply options, the ADI AD4851 uses a precision, low‑drift internal reference and reference buffer. Each channel supports independently configurable SoftSpan ranges, allowing the tailoring of input ranges to the application’s signal swing. This input range tailoring reduces the need for external signal‑conditioning components. The AD4851 also integrates seamless high dynamic range (SHDR) technology, which automatically adjusts the channel’s input signal path gain on each sample, reducing converter noise without affecting linearity.
The AD4851 can directly digitize signals with arbitrary swings on INx+ and INx- by utilizing the 11MHz input bandwidth, picoamp‑level input bias current buffers, extensive input common‑mode range, and 120dB common‑mode rejection ratio (CMRR). Optional 16‑bit oversampling further enhances both SNR and dynamic range. Additionally, per‑channel calibration options (including offset, gain, and phase adjustments) allow system‑level error correction upstream of the DAS.
For configuration, the ADI AD4851 offers an SPI‑based register interface compatible with 0.9V to 5.25V supply levels. The device supports both LVDS and CMOS output data formats, selectable via the LVDS/CMOS pin, and allows between one and four CMOS data output lines to balance the bus width with throughput requirements. The compact 7mm × 7mm, 64‑ball BGA package includes all essential power‑supply and reference bypass capacitors, reducing overall component count, minimizing layout sensitivity, and decreasing total solution footprint. The device operates over an extended industrial temperature range from -40°C to +125°C.
Features
- Complete 16-bit data acquisition system
- Simultaneous sampling of four internally buffered channels
- 250kSPS per channel throughput
- Differential, wide common-mode range inputs
- ±75pA typical input leakage at +25°C
- <300ns full-scale input step settling time
- Integrated reference and reference buffer (4.096V)
- Integrated supply decoupling capacitors
- 36mW per channel at 250kSPS, scales with throughput
- Minimal external signal conditioning
- Seamless high dynamic range
- Per sample, per channel automatic gain ranging
- Maintains ppm-level INL
- Per channel SoftSpan input ranges, bipolar or unipolar
- ±40V, ±25V, ±20V, ±12.5V, ±10V, ±6.25V, ±5V, ±2.5V
- 0V to 40V, 25V, 20V, 12.5V, 10V, 6.25V, 5V, 2.5V
- Rail-to-rail input overdrive tolerance
- High performance
- ±160μV typical INL (±40V range)
- 94.6dB typical single-conversion SNR (±40V range)
- 98.1dB typical single-conversion DR (±40V range)
- -117dB typical THD (±40V range)
- 120dB typical CMRR
- Digital flexibility
- SPI CMOS (0.9V to 5.25V) and LVDS serial input and output
- Optional oversampling with 16-bit digital averaging
- Optional offset, gain, and phase correction
- 7.00mm × 7.00mm, 64-ball BGA full solution footprint
Applications
- Automatic test equipment
- Avionics and aerospace
- Instrumentation and control systems
- Semiconductor manufacturing
- Test and measurement
Specifications
- 7.25V to 48V power supply input range
- Analog inputs
- 120dB typical CMRR
- 0mA to 10mA maximum input overdrive current tolerance range
- ±40nA input leakage current range
- 1000GΩ typical input resistance
- 4pF typical input capacitance
- 1ns typical aperture delay
- 300ps typical aperture delay matching
- 1ps RMS typical aperture jitter
- 300ns typical full-scale input step settling time
- Power dissipation
- 443mW maximum CMOS conversion data output
- 475mW maximum LVDS conversion data output
- AC accuracy
- 98.1dB typical oversampled dynamic range
- 94.6dB typical Signal-to-Noise-and-Distortion (SINAD) ratio
- DC accuracy
- 76µV to 1220µV maximum INL error range
- ±0.2LSB typical Differential Nonlinearity (DNL) error
- 73µVRMS to 461µVRMS typical transition noise range
- ±1300µV zero-scale error
- ±1.5µV/°C typical zero-scale error drift
- ±0.035%FS full-scale error
- ±1.5ppm/°C typical full-scale error drift
- -40°C to +125°C operating temperature range
Functional Block Diagram
