Analog Devices Unveils Op Amp

'Industrial amplifiers are subject to fault voltages from a variety of sources, including electro-magnetic interference, damaged cabling, lightning strikes and other disturbances on the power grid, incorrect hookups to other system components and power-line surges when power to the system is restored after routine service or equipment upgrades,'said Steve Sockolov, product line director, Precision Signal Processing, Analog Devices. 'Such over-voltage conditions can cause phase inversion or damage the amplifier and other circuitry, resulting in system lock-up or outright failure.'

The ADA4091-2 op amp's performance is fully specified, including the device's on-chip over-voltage circuitry. This simplifies equipment design and error analysis and results in more consistent output readings in industrial process controls, battery-powered instrumentation, power supply control and protection systems and remote sensors.

By providing localized signal conditioning and the industry's best combination of low offset, low offset drift and wide gain-bandwidth, the ADA4091-2 delivers precision performance across a variety of sensor inputs, while the over-voltage protection feature prevents phase-inversion errors and excessive input current flows during transient or fault conditions. The performance of competing op amps must be evaluated to compensate for the error effects of discrete over-voltage circuitry on system performance, which adds a layer of complexity and uncertainty to the design process.

By integrating the requisite over-voltage protection circuitry, the ADA4091-2 dual micro-power op amp with rail-to-rail inputs and output allows system designers to reduce the number of external components needed to ensure stable system operation.

The new 1.5-MHz op amp features a low 350-µA-per-channel supply current, a 0.5-V/µs slew rate, and offset voltage of 500 µV max., which assure system accuracy with varied sensor types in harsh operating environments while eliminating the need for cooling fans or other costly thermal management devices. The 36-V ADA4091-2 op amp protects up to 12 V above and below the supply rails at ±15 V and 25 V above and below the supply rails at ±5 V. In an industrial signal chain, the ADA4091-2 is well matched to operate with a range of ADCs (analog-to-digital converters), including ADI's AD761x, AD763x and AD7591 PulSARÂ ADCs and AD7190 and AD7794 sigma-delta ADCs.