Reduces space and cost by removing front-end signal conditioning circuits
Direct sensor connection without loss of measurement accuracy due to CMRR characteristics

Analog Devices announced the release of the new LTC2358-18, an 18-bit, 8-channel simultaneous sampling SAR (successive approximation register) ADC with a built-in picoampere (pA) input buffer.

Particularly when board space is limited, the LTC2358-18 reduces space and cost by eliminating the front-end signal conditioning circuitry commonly required to drive buffered switched-capacitor ADC inputs. By saving three amplifiers, six resistors, and two capacitors per channel, a total of 88 components can be reduced across eight channels. This not only significantly reduces board area and bill of materials (BOM) costs but also provides a reduction in power consumption of over 40%.

Due to its picoampere input and 128dB CMRR characteristics over a 30V _PP common mode range, the LTC2358-18 can be directly connected to various sensors without compromising measurement accuracy.

The LTC2358-18 converts 8 channels with a throughput of 200 ksps per channel, and offers greater flexibility through an individually configurable SoftSpan™ input range. Each channel can be programmed on a conversion-by-conversion basis to accept ±10.24V, 0V to 10.24V, ±5.12V, or 0V to 5.12V unipolar, true bipolar, fully differential, or arbitrary input signals.



The differential analog input operates over a wide input common-mode range of 30V, allowing this ADC to directly convert various signals into digital while simplifying signal chain design. Combined with such input signal flexibility and excellent characteristics such as a maximum INL of ±3.5 LSB, no code loss at 18 bits, and 96.4 dB SNR, the LTC2358-18 is ideal for high-performance industrial process control, test and measurement, power line monitoring, and motor control applications.

The LTC2358-18 features a precision internal reference supporting a maximum temperature factor of 20 ppm/ ^° C and an integrated reference buffer capable of precise one-shot measurements, providing space-saving benefits for densely packaged circuit boards. An optional external 5V reference can be used to extend the analog input range to ±12.5V. The device consumes 219 mW of power when converting eight channels simultaneously at 200 ksps per channel and offers nap and power-down modes to reduce heat dissipation at slower throughputs.

In addition to its unique analog characteristics, the LTC2358-18 offers excellent digital flexibility featuring pin-selectable SPI CMOS and LVDS serial interfaces. With a wide digital output power range, it can communicate with any CMOS logic between 1.8V and 5V. In CMOS mode, applications can select from 1 to 8 lanes of serial output data, allowing users to optimize bus width and data throughput. LVDS mode uses differential signaling to provide low-noise, high-speed communication over longer distances. In addition, these I/O interface options enable the LTC2358-18 to communicate on par with legacy microcontrollers (MCUs) and modern FPGAs.