Optocouplers For 3.3V Logic Devices Reduce Power By 50%

Claimed as the industry's first optocouplers directly compatible with today's 3.3V low-power microcomputer chips and logic families, this new line of optocouplers eliminates the need for an additional 5V power supply in many applications. The devices are said to reduce power consumption by at least 50% each if the losses in dc/dc converter circuits are included. The new family from 2.7V to 3.3V includes single- and dual-channel optocouplers in dual-inline and miniature SO-8 surface-mount packages. Performance characteristics include speeds from 1 Mb/s to 15 Mb/s and isolation of up to 25 kV/µs.
The low-power devices find use in telecomm, computing and industrial applications, particularly in battery-operated portable and handheld equipment. Typical applications include computer peripheral interface, microprocessor system interfaces, digital isolation for A/D and D/A conversions, high speed logic ground isolation and instrument I/O isolation. They are also claimed as the first commercially available optocouplers designed to meet the industry's standard for low-voltage transistor logic.
The diode-transistor optocouplers use an insulating layer between an LED and an integrated photodetector to provide electrical insulation between input and output. Separate connections for the photodiode bias and output-transistor collector increase the speed up to 100x that of a conventional phototransistor coupler, it's claimed, by reducing the base-collector capacitance.
The devices come in an 8-pin DIP and in industry standard SO-8 packaging in production quantities with price ranging from $0.80 to $1.40 each for the single-channel optocouplers and $1.60 to $2.80 each for the dual-channel optocouplers.