Optical isolator provides data transfer, electrical isolation

TT electronics Optek Technology has developed an axial optical isolator designed to provide electrical isolation and data transfer. Designated the OPI1270 series axial analog isolator, the device consists of a visible red LED emitter and a phototransistor detector housed in separate opaque molded plastic housings and coupled by a shrouded optical cable that is said to give the product high noise immunity. The isolators are offered with standard lengths of 32-, 40- and 80mm, and can be produced in custom lengths up to 10m or longer.

"The OPI1270 series devices were designed for applications that require high voltage isolation between input and output, or transmission of a signal from one location to another on the same or adjacent PC board," said Roland Chapa, Optek's assemblies business unit director. "The opaque housing and shrouded cable shields the optical signal from dust, dirt, oil and other particles, making the isolator ideal for contaminated environments."

Applications for the isolator include industrial, medical and office equipment, as well as electrical isolation circuits in harsh environments.

The isolators are rated for a minimum of 20kV isolation for the 32mm device, and carry a power dissipation rating of 100mW. The AlInGaP LED (emitter) produces red light with a peak wavelength of 645nm, with on-state collector current ranging from 0.9V to 1.5V (I_F=20mA) and maximum collector dark current of 80μA (V_R=3V).

The phototransistor (sensor) exhibits a maximum collector current of 50mA (V_CE=10V, E_E=0). Collector-emitter breakdown voltage is 33V (min.), and emitter-collector breakdown voltage is 5.5V (min.) (both measured at 100μA, E_E=0). The current transfer ratio for the device is typically 10 percent with a LED current of 20mA.

The operating temperature range is -20°C to 85°C, and the device is also compatible with high temperature soldering processes of 260°C.

The OPI1270 series isolators are RoHS-compliant. Optek said that it will also produce devices to meet customer requirements, including custom electrical specifications, as well as special connectors or cabling configurations.

Typical pricing for the OPI1270-032 isolator starts at $4.97 each in quantities of 1,000 pieces, with samples available immediately. Production quantity lead times, if stock is not available, are from six to eight weeks.