The ADA4530-1 is a femtoampere (10−15 A) level input bias current operational amplifier suitable for use as an electrometer that also includes an integrated guard buffer. It has an operating voltage range of 4.5 V to 16 V, enabling it to operate in conventional 5 V and 10 V single supply systems as well as ±2.5 V and ±5 V dual supply systems.
It provides ultralow input bias currents that are production tested at 25°C and at 125°C to ensure the device meets its performance goals in user systems. The integrated guard buffer isolates the input pins from leakage in the printed circuit board (PCB), minimizes board component count, and enables easy system design. The ADA4530-1 is available in an industry-standard surface-mount 8-lead SOIC package with a unique pinout optimized to prevent signals from coupling between the sensitive input pins, the power supplies, and the output pin while enabling easy routing of the guard ring traces.
The ADA4530-1 also offers low offset voltage, low offset drift, and low voltage and current noise needed for the types of applications that require such low leakages.
To maximize the dynamic range of the system, the ADA4530-1 has a rail-to-rail output stage that can typically drive to within 30 mV of the supply rails under a 10 kΩ load.
The ADA4530-1 operates over the −40°C to +125°C industrial temperature range and is available in an 8-lead SOIC package.
**Applications**
Laboratory and analytical instrumentation: spectrophotometers, chromatographs, mass spectrometers, and potentiostatic and amperostatic coulometry
Instrumentation: picoammeters and coulombmeters
Transimpedance amplifier (TIA) for photodiodes, ion chambers, and working electrode measurements
High impedance buffering for chemical sensors and capacitive sensors
### Features and Benefits
Low input bias current
±20 fA maximum at TA = 25°C (guaranteed at production test)
±20 fA maximum at −40°C < TA < +85°C
±250 fA maximum at −40°C < TA < +125°C (guaranteed at production test)
Low offset voltage: 50 μV maximum over specified CMRR range
Offset voltage drift: ±0.13 μV/°C typical, ±0.5 μV/°C maximum
Integrated guard buffer with 100 μV maximum offset
Low voltage noise density: 14 nV/√Hz at 10 kHz
Wide bandwidth: 2 MHz unity-gain crossover
Supply voltage: 4.5 V to 16 V (±2.25 V to ±8 V)
Operating temperature: −40°C to +125°C
Long-term offset voltage drift (10,000 hours): 0.5 μV typical
