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24-bit A/D integrates amplifier front end

Milpitas, Calif. — Designed for high impedance sensors, Linear Technology Corp. today unveiled an ultra high precision, multiplexed 24-bit no latency Delta-Sigma analog-to-digital (A/D) converter with an integrated high performance amplifier.

The LTC2442 achieves 1 ppm linearity with the amplifier configured as a unity gain buffer. Optional external resistors may be connected to the amplifier to increase the gain for low level input signals. This converter allows the amplifier supply rails to be connected to VCC and ground or biased beyond the rails for rail-to rail input signals.

The LTC2442's proprietary architecture rejects channel-to-channel crosstalk and it's immune to lockup due to large input disturbances, according to the company. The architecture ensures stable dc accuracy through continuous transparent offset and full-scale calibration.

The integrated amplifiers are said to reduce overall circuit size, improve the dc linearity and provide additional design flexibility with optional external gain setting resistors.

Ten no latency speed and resolution combinations from 6.9 Hz to 3.5 kHz are digitally selectable with noise as low as 220-nV rms. In addition, a one cycle latency mode can be selected for each speed/resolution combination enabling output rates up to 7 kHz (8 kHz with an external oscillator) with 17-bits noise performance. Any combination of up to four single-ended inputs or up to two differential inputs can be selected with a common mode input range from ground to VCC. The first conversion following a new channel or speed selection is valid.

 
 
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The LTC2442 is specified for the commercial and industrial temperature ranges and is available in the 36-pin SSOP. Pricing starts at $7.45 each for the LTC2442 in 1,000-piece quantities. Click here for the LTC2442 data sheet.

Linear Technology Corp. , 1-800-454-6327, www.Linear.com.

Linear's converter release follows two other high-resolution A/D converter announcements this month from Microchip Technology Inc. (Chandler, Ariz.) and Texas Instruments Inc. (Dallas).

Click here for more details on Microchip’s 22-bit A/Ds (MCP3551 and MCP3553) at eeProductCenter.

Click here for more details on TI’s 24-bit A/D (ADS1258) at eeProductCenter.

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