Datasheet ADA4530-1 (Analog Devices)

Femtoampere Input Bias Current Electrometer Amplifier Data Sheet ADA4530-1 FEATURES PIN CONNECTION DIAGRAM Low input bias current ADA4530-1 ±20 fA maximum at TA = 25°C (guaranteed at production test) +IN 1 8 –IN ±20 fA maximum at −40°C < TA < +85°C GRD 2 7 GRD ±250 fA maximum at −40°C < TA < +125°C (guaranteed at IC 3 6 OUT production test) V– 4 5 V+ Low offset voltage: 50 µV maximum over specified CMRR range Offset voltage drift: ±0.13 µV/°C typical, ±0.5 µV/°C maximum NOTES 1. IC = INTERNAL CONNECTION. THIS Integrated guard buffer with 100 µV maximum offset
001
PIN MUST BE CONNECTED TO V– OR LEFT UNCONNECTED. Low voltage noise density: 14 nV/√Hz at 10 kHz
13405- Figure 1.
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 Temperature hysteresis: 1.5 µV typical APPLICATIONS Laboratory and analytical instrumentation: spectrophoto- meters, 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 GENERAL DESCRIPTION
The ADA4530-1 is a femtoampere (10−15 A) level input bias To maximize the dynamic range of the system, the ADA4530-1 current operational amplifier suitable for use as an electrometer has a rail-to-rail output stage that can typically drive to within that also includes an integrated guard buffer. It has an operating 30 mV of the supply rails under a 10 kΩ load. voltage range of 4.5 V to 16 V, enabling it to operate in conven- The ADA4530-1 operates over the −40°C to +125°C industrial tional 5 V and 10 V single supply systems as well as ±2.5 V and temperature range and is available in an 8-lead SOIC package. ±5 V dual supply systems.
1000
It provides ultralow input bias currents that are production
V –40°C TO +125°C LIMIT SY = 10V V
tested at 25°C and at 125°C to ensure the device meets its perfor-
CM = VSY/2 100 RH < 10%
mance goals in user systems. The integrated guard buffer
–40°C TO +85°C LIMIT
isolates the input pins from leakage in the printed circuit board
10
(PCB), minimizes board component count, and enables easy
)
system design. The ADA4530-1 is available in an industry-
1 (fA I B
standard surface-mount 8-lead SOIC package with a unique pinout optimized to prevent signals from coupling between the
0.1 IB+ I
sensitive input pins, the power supplies, and the output pin
B–
while enabling easy routing of the guard ring traces.
0.01
The ADA4530-1 also offers low offset voltage, low offset drift,
0.001
and low voltage and current noise needed for the types of
0 10 20 30 40 50 60 70 80 90 100 110 120 130
202 applications that require such low leakages.
TEMPERATURE (°C)
13405- Figure 2. Input Bias Current (IB) vs. Temperature, VSY = 10 V
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Document Outline FEATURES APPLICATIONS PIN CONNECTION DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS 5 V NOMINAL ELECTRICAL CHARACTERISTICS 10 V NOMINAL ELECTRICAL CHARACTERISTICS 15 V NOMINAL ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS MAIN AMPLIFIER, DC PERFORMANCE MAIN AMPLIFIER, AC PERFORMANCE GUARD AMPLIFIER THEORY OF OPERATION ESD STRUCTURE INPUT STAGE GAIN STAGE OUTPUT STAGE GUARD BUFFER APPLICATIONS INFORMATION INPUT PROTECTION SINGLE-SUPPLY AND RAIL-TO-RAIL OUTPUT CAPACITIVE LOAD STABILITY EMI REJECTION RATIO HIGH IMPEDANCE MEASUREMENTS INPUT BIAS CURRENT INPUT RESISTANCE INPUT OFFSET VOLTAGE INSULATION RESISTANCE GUARDING DIELECTRIC RELAXATION HUMIDITY EFFECTS CONTAMINATION CLEANING AND HANDLING SOLDER PASTE SELECTION CURRENT NOISE CONSIDERATIONS LAYOUT GUIDELINES PHYSICAL IMPLEMENTATION OF GUARDING TECHNIQUES GUARD RING GUARD PLANE VIA FENCE CABLES AND CONNECTORS ELECTROSTATIC INTERFERANCE PHOTODIODE INTERFACE DC ERROR ANALYSIS AC ERROR ANALYSIS NOISE ANALYSIS DESIGN RECOMMENDATIONS DESIGN EXAMPLE POWER SUPPLY RECOMMENDATIONS POWER SUPPLY CONSIDERATIONS LONG-TERM DRIFT TEMPERATURE HYSTERESIS OUTLINE DIMENSIONS ORDERING GUIDE