LTM2893/LTM2895 SPI μModule® Isolators

The LTM2893 and LTM2895 are high-speed, isolated μModule (micromodule) SPI interfaces from Analog Devices with ADC control signals. The LTM2893 is optimized for isolating 1-Msps, high-resolution, 18-bit SAR ADCs, such as the LTC2338 and similar families, and can interface with most general-purpose ADCs. The LTM2895 works with DACs and general-purpose DACs that have a mode (0, 0) SPI interface. The LTM2893-1 is optimized for isolating the LTC2348 and similar families of simultaneous sampling ADCs that require writing configuration settings into the ADC. The LTM2893 isolates the conversion start sampling signal with a very-low aperture jitter (30 ps) and low latency (20 ns).

The interface enables fast throughput with no cycle latency, which makes the LTM2893 and LTM2895 ideally suited for a wide variety of applications. The LTM2893 has a high-speed, SPI-compatible serial port that supports 1.71 V to 5.5 V logic and is configurable for ADCs with 8 to 32-bit SPI word lengths. It also isolates three select signals (SA, SB, SC) for controlling analog multiplexers or gain settings.

The isolation barrier tolerates large voltage ground variations between the logic interface and the isolated side of the LTM2893. Uninterrupted communication is maintained during voltage transients greater than 50 kV/μs.

Video: LTM2893 100 MHz Isolated SPI Analog-to-Digital Converter Solution

Typical Application Diagram