Electronic Design

16-Bit Programmable ADC Provides 25-V Protection

A 16-bit, 8-channel, 100-ksample/s analog-to-digital converter (ADC), the LTC1859 from Linear Technology, offers software programmable input ranges that are fault-protected to ±25 V. Using a serial interface, designers can program the device to accept 0-5-V, 0-10-V, ±5-V, and ±10-V inputs, allowing one board design to accommodate several industrial applications (see the Figure). An over-voltage fault up to ±25 V will not corrupt the accuracy of the selected channel. The ADC's multiplexer can be configured to accept four differential inputs, eight single-ended inputs, or combinations of both. Performance includes 15-bit no missing codes over temperature, ±3-LSB max INL, and 87-dB signal-to-noise ratio.

The LTC1859 operates from a single 5-V supply, while consuming only 40 mW. It includes a 2.5-V internal reference with a temperature coefficient of ±10 ppm/°C, which can be externally driven if greater accuracy is required. For power sensitive applications, the device offers two power-down modes in which dissipation drops to 27.5 mW (nap mode) with the reference active, or 40 µW (sleep mode) with the reference completely powered down. Two other versions, the 12-bit LTC1857 and the 14-bit LTC1858 are pin-compatible. Each device is available in SSOP-28 packages. The entire family is available in commercial and industrial temperature ranges.


The LTC1859, LTC1858, and LTC1857 are available now.


Pricing begins at $17.95 each for the LTC1859, $12.95 each for the LTC1858, and $8.95 each for the LTC1857 in 1,000-piece quantities.


Visit www.linear.com.

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