18-bit, 8-channel SAR ADC offers independently configurable input ranges

Milpitas, CA. Linear Technology has introduced the LTC2335-18, an 18-bit, 8-channel 1-MS/s multiplexed input successive approximation register (SAR) ADC with independently configurable input ranges. Each SoftSpan input can be software configured on a conversion-by-conversion basis to accept ±10.24-V, 0- to 10.24-V, ±5.12-V or 0- to 5.12-V true bipolar input signals.

The on-chip sequencer allows the LTC2335-18 to be programmed to cycle through a sequence of channels and ranges without further user intervention. The differential analog inputs operate over a wide -16.5-V to 34-V input common-mode range, allowing the ADC to directly digitize a variety of signals to simplify signal-chain design. The input signal flexibility, combined with 96.7-dB SNR and 1MS/s throughput, makes the LTC2335-18 suitable for high performance industrial process control, test and measurement, power line monitoring, and instrumentation applications.

The LTC2335-18 features a precision internal reference with 20-ppm/°C maximum temperature coefficient and an integrated reference buffer capable of accurate one-shot measurements, providing space savings in densely packed circuit boards. Optionally, an external 5-V reference may be used to expand the analog input range to ±12.5 V. The device dissipates 180 mW when converting at 1 MS/s, and features nap and power-down modes to reduce power dissipation at slower throughputs.

The LTC2335-18 features pin-selectable SPI CMOS and LVDS serial interfaces. The wide digital output supply range allows the device to communicate with any CMOS logic between 1.8 V and 5 V. The serial LVDS mode offers low noise, high speed communications over greater distances using differential signaling. Together, these I/O interface options enable the LTC2335-18 to communicate equally well with legacy microcontrollers and modern FPGAs.

The LTC2335-18 joins a high performance family of multichannel 18-/16-bit SAR ADCs with true bipolar ±10.24-V simultaneous sampling inputs (LTC2348). All specifications are guaranteed over the extended -40°C to 125°C temperature range. The LTC2335-18 is available now in a 48-lead, 7-mm x 7-mm LQFP package and is priced starting at $18.95 each in 1,000-piece quantities.

www.linear.com/product/LTC2335-18