Medical device solution based on AD4002

The AD4002 is low noise, low power, high speed, 18-bit, precision successive approximation register (SAR) analog-to-digital converters (ADCs). The AD4002 offer 2 MSPS, 1 MSPS, and 500 kSPS throughputs, respectively. They incorporate ease of use features that reduce signal chain power consumption, reduce signal chain complexity, and enable higher channel density. 

The high-Z mode, coupled with a long acquisition phase, eliminates the need for a dedicated high power, high speed ADC driver, thus broadening the range of low power precision amplifiers that can drive these ADCs directly while still achieving optimum performance. 

The input span com-pression feature enables the ADC driver amplifier and the ADC to operate off common supply rails without the need for a negative supply while preserving the full ADC code range. The low serial peripheral interface (SPI) clock rate requirement reduces the digital input/output power consumption, broadens processor options, and simplifies the task of sending data across digital isolation.

Operating from a 1.8 V supply, the AD4002/AD4006/AD4010 sample an analog input (IN+) from 0 V to VREF with respect to a ground sense (IN−) with VREF ranging from 2.4 V to 5.1 V. The AD4002 consumes only 14 mW at 2 MSPS with a minimum SCK rate of 75 MHz in turbo mode; the AD4006 consumes only 7 mW at 1 MSPS; and the AD4010 consumes only 3.5 mW at 500 kSPS. The AD4002/AD4006/AD4010 all achieve ±3.2 LSB integral nonlinearity error (INL) maximum, no missing codes at 18 bits, and 95 dB signal-to-noise ratio (SNR) for an input frequency (fIN) of 1 kHz. The reference voltage is applied externally and can be set independently of the supply voltage.

The SPI-compatible versatile serial interface features seven different modes including the ability, using the SDI input, to daisy-chain several ADCs on a single 3-wire bus, and provides an optional busy indicator.

The AD4002 is compatible with 1.8 V, 2.5 V, 3 V, and 5 V logic, using the separate VIO supply.

The AD4002 is available in a 10-lead MSOP and 10-lead LFCSP, and the AD4010 is available in a 10-lead LFCSP, with operation specified from −40℃ to +125℃. The devices are pin compatible with the 18-bit, 2 MSPS AD4003 (see Table 8).

Medical device solution framework based on AD4002

　　10-lead packages: 3 mm × 3 mm LFCSP, 3 mm × 4.90 mm MSOP

The AD4002/AD4006/AD4010 Application

　　Precision data acquisition systems

AD4002/AD4006/AD4010 Multiple Power Supply Typical Application Block Diagram