Optically-Isolated Voltage Sensors from Avago Technologies
News Release from:
12 July 2012
Avago have today revealed the availability of a new family of optically-isolated voltage sensors. This family is the industry's first series of optical isolation amplifiers based on sigma-delta modulation that is specifically optimized for voltage sensing.
Targeted for applications such as sensing voltages in electronic power conversion systems commonly found in motor drives, switching power supplies and renewable energy systems, as well as sensor interfaces such as NTC thermistor isolation in IGBT modules, the ACPL-C87B, C87A, and C870 provide designers with a 2-V input range and high 1 G‡ input impedance.
For general applications, the ACPL-C87A(±1% gain tolerance) and the ACPL-C870 (±3% gain tolerance) are recommended. For high-precision servo and motor drives, the ACPL-C87B (±0.5% gain tolerance) can be used. The voltage sensors feature a 1V/V unity gain with low gain drift of -35ppm/˚C and non-linearity is kept to within 0.1% max. The voltage sensors include an active-high shut-down-pin which reduces the IDD1 current to only 15 microA during standby, which makes the sensors well-suited for battery-powered and other power-sensitive applications.
“This new family of optically-isolated voltage sensors has a high 1 G‡ input impedance, which simplifies the resistor network design by allowing higher-value resistors to be used to scale the voltage.” explains Lee Kheng Jam, Marketing Director for Optocoupler products at Avago. “As a result, it reduces loading power losses, thus achieving better system efficiency.”
Avago Technologies' Optical Isolation Amplifiers have been using advanced Sigma-Delta modulation technology and chopper-stabilized amplifiers to provide accurate, safe, and reliable current and voltage sensing for over 2 decades in motor drives and power converters. Differential outputs on the new devices provide unequalled isolation-mode noise rejection, low offsets, high gain accuracy and stability, and a wide signal band width of 100 kHz.
The built-in reinforced safety insulation and high CMR performance prevents erroneous voltage measurements and ensures reliable operation in a noisy environment. The optically-isolated voltage sensors have a 15 kV/µs common-mode transient immunity.Safety approvals include CSA and IEC/EN/DIN EN60747-5-5 with a VIORM of 1230 V peak.Additionally, the sensors are UL recognized with 5000 Vrms for1 minute per UL1577.
The ACPL-C87xvoltage sensors are housed in stretched 8-lead SO-8 plastic packages with 8mm creepage and clearance that meet worldwide regulatory safety standards. The sensors also have a wide operating temperature range of -40 to +105 °C.
Samples and production quantities are available now through Avago’s direct sales channel and worldwide distribution partners.