Analog Devices' LTC4332 is a rugged SPI extender engineered for operation in challenging industrial environments, where noise and long distances pose communication challenges. Featuring a robust ±60 V fault-protected differential transceiver, this device enables SPI data transmission, including an interrupt signal, at speeds of up to 2 MHz over two twisted-pair cables. Its extended common mode range and high common mode rejection on the differential link ensure tolerance to significant ground differences between nodes.
The LTC4332 incorporates a control interface with a separate secondary select for configuration and fault monitoring, enhancing its usability and reliability in industrial applications.
A practical demonstration circuit, DC2799A, showcases the LTC4332's capabilities by extending an SPI with three secondary devices to distances of up to 1200 m (150 m with a 500 kHz SCK as factory configured). Moreover, the DC2799A is designed to be compatible with the widely used Pmod interface, facilitating easy evaluation with various primary and secondary devices within this ecosystem.
2 MHz SCK over 10 m, operation to 1200 m
Three extended secondary selects
Protected from overvoltage line faults to ±60 V
±40 kV HBM ESD on link pins
IEC ESD ±6 kV and EFT ±4 kV on link pins
Extended common mode range: ±25 V
Extended interrupt
Separate programmable SPI modes
3 V to 5.5 V supply voltage
1.62 V to 5.5 V logic supply
4 mm × 5 mm 20-lead QFN package
Industrial control and sensors
Lighting and sound system controls
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