SAR convertors improve linearity

High-linearity 16bit A/D convertors provide an easy performance upgrade for portable, battery-powered applications, including industrial data acquisition and portable medical instrumentation.

Texas Instruments has introduced a pair of 16bit analogue-to-digital convertors (ADCs) featuring 2x better linearity than competing devices (+/-1.5LSB maximum INL).

Combined with low-power operation, best-in-class temperature drift and either an industry-standard MSOP-8 or a 3 x 3mm SON-8 package, the ADS8317 and ADS8326 provide an easy performance upgrade for portable, battery-powered applications including industrial data acquisition and portable medical instrumentation.

When operating at the full datarate of 250Ksample/s, the ADCs require very little power (10mW at 5V).

At 200Ksample/s, power dissipation is less than 4mW at 2.7V.

When operating at lower datarates, the high-speed operation enables the devices to spend most of the time in a power-down mode.

For example, the average power dissipation is less than 0.2mW at a 10Ksample/s datarate (2.7V).

Both devices offer best-in-class temperature drift specifications for reliable measurements across the operating temperature range.

The ADS8317 (true differential input) features 0.1ppm/C gain error drift and 0.2ppm/C offset error drift.

The ADS8326 (single-ended input) delivers 0.3ppm/C gain error drift and 0.2ppm/C offset error drift.

The ADS8317 and ADS8326 are based on a successive approximation (SAR) capacitive charge redistribution architecture that inherently includes a sample/hold function.

Each offers a high-speed wide-voltage SPIT/SSI serial interface that can be used in a multiple-device daisychain configuration.

Both devices operate over a wide supply voltage range of 2.7 to 5.5V.

The devices are the latest additions to TI's leading portfolio of pin-compatible MSOP-8 SAR convertors, which provide designers with resolution, speed and performance upgrades for their existing systems without requiring costly and time-consuming redesigns.

Along with the leading ADS83xx ADCs, TI delivers complete signal chain system solutions including the industrial-targeted TMS320C6000 and C5000 digital signal processors and C2000 controllers, as well as MSP430 and TMS470 MCUs.

TI also offers a range of operational amplifiers (such as the OPA365) and voltage references (such as the REF50xx) which are well suited to work with these ADCs to achieve highest performance.

The ADS8317 and ADS8326 are available now in an MSOP-8 package from TI and its authorised distributors.

Pricing for both devices starts at US $5.00 in 1000-piece quantities (suggested resale pricing).

Evaluation modules are also available.

The 3 x 3mm SON-8 package will be available in 1Q 2008.

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