Analog Devices (www.analog.com), a semiconductor company in the signal processing applications field, has launched the electrometer-grade operational amplifier ADA4530-1.

With the ADA4530-1, it is possible to implement chemical analysis equipment that achieves high precision and data repeatability over a wider temperature range as a compact solution, thereby reducing overall bill of materials (BOM) and design footprint.

To this end, the ADA4530-1 operational amplifier provides input bias current that is at least 20 times lower than competing products. Due to this extremely low bias current, the ADA4530-1 is well suited for connecting to sensors sensitive to output load like photodiodes, as well as other high output impedance sensors frequently used in precision monitoring/analysis equipment such as spectrophotometers, chromatographs, and mass spectrometers, and in potentiostatic and amperostatic coulometry measurement equipment.

This new operational amplifier can also be used as a front-end amplifier for picoammeter or coulombmeter measurement systems, or as a transimpedance amplifier for photodiodes, ion chambers, and working electrode measurements, or as a high-impedance buffer for chemical and capacitive sensors.

Bias current is 20 times lower at 125℃ and 50 times lower at 85℃ compared to competing products


The input bias current of the ADA4530-1 operational amplifier decreases to 250fA at 125℃ and 20fA at 85℃, which is 20 times lower at 125℃ and 50 times lower at 85℃ compared to competing products.

Furthermore, the ADA4530-1 is the only operational amplifier that can maintain input bias current at 20fA equally across temperatures between room temperature and 85℃, and among comparable products, the ADA4530-1 is the only operational amplifier that has undergone full production testing for bias current at both room temperature and 125℃.

Even the most similarly specified competing products rarely specify input bias current at 125℃, and none have undergone production testing for bias current at room temperature. If production testing is not performed at room temperature, system designers must reserve a certain frequency guard band to account for large variations in bias current, which prevents full utilization of sensor sensitivity.

Additionally, the ADA4530-1 integrates an on-chip guard buffer that provides useful output for driving interconnected guard shields that track input common-mode voltage and reduce the effects of stray capacitance occurring in PCB guard rings or sensitive connections between sensors and amplifiers.

Therefore, by using the ADA4530-1 amplifier, designers do not need to design separate circuits to provide the required output drive, thereby saving design time, cost, and PCB space, and simplifying sensor interface design.