Octal high-side switch boosts throughput and channel density

May 12, 2015 // By Graham Prophet
Maxim Integrated’s octal digital output switch increases throughput by up to 70x for PLCs, HVAC, and industrial equipment.

This eight-channel device provides up to 70x faster speed, uses over 20% less power, and occupies 40% less space than existing solutions. It is controlled by an eight-bit parallel interface, or via a standard Serial Peripheral Interface (SPI) which is also used for configuration and monitoring. Multiple devices can be daisy-chained to support additional I/O points via the single SPI interface, requiring only three isolators for all channels to provide further savings in cost, board space, and power. The serial mode includes cyclic redundancy checking (CRC) for assured data integrity, as well as global and per-channel diagnostics for remote system monitoring.

Maxim offers both a complete reference design (MAXREFDES63#) as well as an evaluation (EV) kit with special prototyping features. The credit-card-sized reference design integrates the MAX14900E, a microcontroller, isolated I/O port, power supplies, UART, and USB port to simplify incorporating the device into the final OEM product design, as well as provide a means for quick evaluation.

The eight digital channels require 3 mA (maximum) of supply current; the device operates from a supply range of 10V to 36V and is compatible with the 24V rail of many factory systems. With an input-to-output propagation delay of 300 nsec (typical)/800 nsec (maximum), it can support fast switching rates of up to 100 kHz in push-pull configuration. On-resistance, a critical factor in static power dissipation is just 85 mΩ (typical) and 165 mΩ (maximum). It can drive current loads up to 850 mA; outputs can be used in parallel to achieve even higher drive-current rating.

In a 48-pin 7 × 7 mm QFN package it uses significantly less board space. It has per-channel and global diagnostics/monitoring via its SPI port, while users can access the I/O via an eight-bit parallel port. The serial link includes CRC error detection for enhanced data-link integrity. MAX14900E is specified over the -40 °C to +125 °C range.

Maxim Integrated; www.maximintegrated.com