ADI’s efficient power drivers for 12-, 14- and 16-bit ADCs

September 24, 2014 // By Graham Prophet
ADI’s ADA4805 family of amplifiers with Dynamic Power Scaling claim best-in-class offset drift, slew rate, noise and distortion performance for portable, battery powered and high-density data acquisition equipment.

These low-power rail-to-rail amplifiers are intended for high-speed data acquisition systems that require exceptional accuracy, precision and power efficiency. For system designers who are looking to achieve full datasheet specifications from high resolution A/D converters, the ADA4805-1 (single) and ADA4805-2 (dual) amplifiers have quiescent current as low as 495 µA. The amplifiers' Dynamic Power Scaling (DPS) feature allows users to dynamically manage the power consumption by shutting-down the amplifier between analogue-to-digital converter samples. This further reduces, by up to 90%, the power consumption — with no performance degradation —when compared to similar solutions.

The 100-MHz ADA4805-1 and ADA4805-2 amplifiers achieve a high slew rate of 160 V/μsec, low noise (5.9 nV/√Hz at 100 kHz) and low distortion (−102 dBc/−116 dBc HD2/HD3 at 100 kHz) while consuming only 1.5 mW. The amplifiers are designed for power-sensitive portable and battery-powered data acquisition devices, such as handheld or portable test and measurement instruments, battery-powered industrial equipment and remote environmental monitoring devices. They can also be used to reduce power and thermal dissipation in high-density applications such as cellular base stations and medical imaging equipment.

With exceptionally low offset-voltage drift of 1.5 µV/°C maximum (0.2 μV / °C typical), the ADA4805 family offers one-eighth the drift of competing high-speed (100 MHz) amplifiers. The combination of superior AC and DC performance allow designers to enhance system sensitivity, dynamic range and overall system accuracy. The ADA4805-1/-2 amplifiers have a wide voltage range, supporting 3-V supplies, and in applications that require a wider dynamic range can also operate on supplies as high as ±5V.

The ADA4805 family efficiently drive a variety of A/D converters such as the AD7980 16-bit 1 MSPS; AD7091 ultra low-power 12-bit, 1 MSPS; AD7902 dual pseudo differential 16-bit 1 MSPS and AD7988 ultra low-power 16-bit SAR converters.

A video is at; www.analog.com/ada4805video