acquisitionZONE Products for the week of June 11, 2012

Texas Instruments Says…

ADS8028: Industry-First 12-Bit A Msample/s SAR ADC With SPICE Model
Model enables designers to quickly simulate, model and test the full analog signal chain

Texas Instruments Incorporated (TI) introduced a successive-approximation-register (SAR) analog-to-digital converter (ADC) with a downloadable TINA-TI SPICE model, enabling system designers to simulate and characterize the full analog signal chain in software for the first time. The model is available for the new 12-bit, 1-MSPS, 8-channel ADS8028, a highly-integrated SAR ADC featuring a low-drift internal voltage reference, wide external analog voltage reference range, wide analog and digital supply ranges, and an internal temperature sensor.

Designers could previously only simulate, model and test up to the SAR ADC, requiring them to invest time and resources building the ADC circuit in hardware. With a downloadable TINA-TI SPICE model available for all new SAR ADCs, designers will be able to fully verify ADC driving circuitry, enabling them to speed product development.

EN-Genius Says…

The ADS8028 is a good new SAR ADC, as we will see, but the real news here is the TINA-TI SPICE model available for it.

With an analog supply range of 2.7 V to 5.25 V and an I/O digital supply range of 1.65 V to 5.25 V the ADS8028 is already a little different from its competitors as an octal 12-bit 1-Msample/s SAR ADC. It offers both an INL and DNL of, typically, ±0.5LSB (±1LSB max) and an SNL of 72 dB, 2 dB off the theoretical 74 dB (with a 50 kHz input at -0.5 dBFS), a SINAD of 71 dB, THD of -82 dB, and SFDR of 84 dB. It has an extremely good 3 dB full-power bandwidth of 30 MHz (10 MHz for 0.1 dB flatness), a conversion time of 660 ns (with a 20 MHz clock) and an acquisition time of 100 ns minimum.

The part has a nominal 2.5 V internal reference with a 150ppm long-term stability that can be overridden with an external reference ranging from 1 V to the analog supply rail. There is also an internal temperature sensor, that can be muxed with the eight analog inputs, with a range from -40ºC to 125ºC, a resolution of 0.25ºC, and a maximum accuracy of ±3ºC (typical ±1ºC).

The SPI is 20 MHz compatible with input logic levels from 0.7 x digital rail high to 0.3 x digital rail low and output levels from 0.8 to 0.2 x digital rail.

The operational consumption of the ADS8028 is about 7.5 mA maximum with both rails at 5.25 V, which falls to about 5 mA in static mode, less than 3 mA in standby, and 10 µA maximum in power-down mode.

The characteristics of the ADS8028 make it ideal for multiple sensor monitoring, power supply monitoring, and various battery-powered and industrial process applications. The whole product is, however, dramatically enhanced by the availability of the TINA-SPICE model which will allow for modeling of a complete sensor, for example, acquisition system. This will save dramatically on design times and costs and will result in better solutions being brought to production. It cannot be over-emphasized how important this development is. If TI are extending this SPICE capability to their complete ADC range it will have a commanding position in the market.

The ADS8028 is in production in QFN-20 with an operating temperature range of -40ºC to 125ºC and priced at $3.25 in 1000-piece lots. An evaluation module is also available.

Data Sheet ADS8028 
TINA-TI SPICE Model