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 drift: 0.13 μV/°C typical, 0.5 μV/°C maximum NOTES 1. IC = INTERNAL CONNECTION. THIS
01
Integrated guard buffer with 100 μV maximum offset
0
PIN MUST BE CONNECTED TO V–
5- 40
OR LEFT UNCONNECTED. Low voltage noise density: 14 nV/√Hz at 10 kHz
13 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 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 GENERAL DESCRIPTION
The ADA4530-1 is a femtoampere (10−15 A) level input bias output stage that can typically drive to within 30 mV of the current operational amplifier suitable for use as an electrometer supply rails under a 10 kΩ load. that also includes an integrated guard buffer. It has an operating The ADA4530-1 operates over the −40°C to +125°C industrial voltage range of 4.5 V to 16 V enabling it to operate in conven- temperature range and is available in an 8-lead SOIC package. tional 5 V and 10 V single supply systems as well as ±2.5 V and
1000
±5 V dual supply systems.
V –40°C TO +125°C LIMIT SY = 10V VCM = VSY/2
It provides ultralow input bias currents that are production
100 RH < 10%
tested at temperature to ensure the device meets its perfor-
–40°C TO +85°C LIMIT
mance goals in user systems. The integrated guard buffer is
10
provided to isolate the input pins from leakage in the printed
) A
circuit board (PCB), minimize board component count, and
(f 1 I B
enable ease of system design. The ADA4530-1 is available in an industry-standard surface-mount 8-lead SOIC package with a
0.1 IB+ I
unique pinout optimized to prevent signals from coupling
B–
between the sensitive input pins, the power supplies, and the
0.01
output pin while enabling easy routing of the guard ring traces.
0.001
The ADA4530-1 also offers low offset voltage, low offset drift, 2
0 10 20 30 40 50 60 70 80 90 100 110 120 130
20 5- and low voltage and current noise needed for the types of 40
TEMPERATURE (°C)
13 applications that require such low leakages. To maximize the Figure 2. Input Bias Current (IB) vs. Temperature, VSY = 10 V dynamic range of the system, the ADA4530-1 has a rail-to-rail
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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 OUTLINE DIMENSIONS ORDERING GUIDE