16-Bit, 20 MSPS, Differential SAR ADC

The AD4084 is a high speed, low noise, low distortion, 16-bit, Easy Drive, successive approximation register (SAR) analog-to-digital converter (ADC). Maintaining high performance (signal-to-noise and distortion (SINAD) ratio > 90dBFS) at signal frequencies in excess of 1MHz enables the AD4084 to service a wide variety of precision, wide bandwidth data acquisition applications. Simplification of the input anti-alias filter design can be accomplished by applying oversampling along with the integrated digital filtering and decimation to reduce noise and lower the output data rate for applications that do not require the lowest latency of the AD4084.

The AD4084 Easy Drive features reduce both signal chain complexity and power consumption while enabling greater channel density and flexibility in companion component selection. The product input structure was designed to minimize any input dependent signal currents, therefore reducing any 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 AD4084 includes several elements that simplify data converter integration: a low drift reference buffer, low dropout (LDO) regulators to generate ADC core and digital interface supply rails, and a 16K result data 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.

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

* High performance

* Throughput: 20MSPS, 78.13ns conversion latency

* INL: ±6ppm (typical), ±10ppm (maximum)

* Dynamic range: 93.1dBFS

* SNR/THD

* 92.6dB (typical)/−115.2dB (typical) at fIN = 1kHz

* 92.4dB (typical)/-103.5dB (typical) at fIN = 1MHz

* Noise spectral density: −163dBFS/Hz

* 16-bit resolution, no missing codes

* Low power

* 66.8mW typical at 20MSPS with −0.5dBFS sine-wave input

* Easy Drive, fully differential input

* 6V p-p differential input range

* Continuous signal acquisition

* Linearized, 5μA/MSPS input current

* Integrated, low-drift reference buffer and decoupling