The Keithley 6221 is a highly precise AC and DC current source designed for applications requiring extremely low current sourcing with low noise, such as nanotechnology, semiconductor characterization, and superconductivity research. It offers low-current sourcing ranges from picoamps to 100mA, high-speed pulsed output capability, and an integrated arbitrary waveform generator.

Specifications

General

ParameterValue
InterfacesGPIB, RS-232, Ethernet (LXI Class C), Trigger Link, Digital I/O, Dedicated RS-232 for Keithley 2182A connection
Display12-character vacuum fluorescent display (VFD)
Cooling SystemForced air, internal fan

Physical

ParameterValue
Power Supply100 V to 240 V AC, 50 Hz to 60 Hz, 120 VA maximum
Operating Temperature0°C to 50°C
Dimensions (W×H×D)213 mm × 89 mm × 370 mm
Weight4.75 kg

DC Current Source Specifications

ParameterValue
Current Output Ranges2 nA, 20 nA, 200 nA, 2 µA, 20 µA, 200 µA, 2 mA, 20 mA, 100 mA
Maximum Output Current105 mA
Source Programming Resolution100 fA (on 2 nA range) to 10 µA (on 100 mA range)
Compliance Voltage Range0.1 V to 105 V, programmable in 10 mV steps
Output Resistance (2 nA range)> 10^14 Ω
Output Resistance (20 nA range)> 10^14 ̢
Output Resistance (200 nA range)> 10^13 ̢
Output Resistance (2 µA range)> 10^12 ̢
Output Resistance (20 µA range)> 10^11 ̢
Output Resistance (200 µA range)> 10^10 ̢
Output Resistance (2 mA range)> 10^9 ̢
Output Resistance (20 mA range)> 10^8 ̢
Output Resistance (100 mA range)> 10^7 ̢
Output Capacitance< 10 pF (2 nA to 20 mA ranges), < 20 pF (100 mA range)
DC Noise (0.1 Hz to 10 Hz, p-p, 2 nA range)80 fA
Settling Time to Rated Accuracy< 100 µs (to 0.1% of final value, resistive load, 2 µA to 100 mA ranges)

AC Current and Waveform Specifications

ParameterValue
Frequency Range1 mHz to 100 kHz
Frequency Accuracy±100 ppm
Waveform TypesSine, Square, Ramp, Arbitrary
Arbitrary Waveform Memory Depth65,536 points
Waveform Sample Rate10 MSps
Total Harmonic Distortion (THD)< 0.1% (typical, 10 Hz to 20 kHz, resistive load)
Amplitude Flatness (10 Hz to 10 kHz)±0.1% (typical)
Amplitude Flatness (10 kHz to 100 kHz)±1.0% (typical)

Pulsed Current Specifications

ParameterValue
Minimum Pulse Width50 µs
Pulse Width Programming Resolution1 µs
Pulse Jitter< 2 µs

Guarding and Isolation

ParameterValue
Maximum Guard Current100 µA
Common Mode Isolation (Output Lo to Chassis)> 10^10 Ω, < 100 pF

Sweep and Buffer Capabilities

ParameterValue
Maximum Sweep Points65,536 (64k)
Buffer Memory Size65,536 points

Connectivity and Control Interfaces

ParameterValue
Output Connector Type3-slot Triaxial (rear panel)
Emulation ModesKeithley Model 220 Command Emulation

Power and Environmental Specifications

ParameterValue
Storage Temperature Range-25°C to 65°C
Warm-up Time1 hour to rated accuracy

Physical and Regulatory Standards

ParameterValue
Form FactorHalf-rack, 2U high
Safety CertificationsConforms to European Union Directive 73/23/EEC, EN 61010-1
EMC ComplianceConforms to European Union Directive 89/336/EEC, EN 61326-1

Accuracy (1 Year, 18°C–28°C)

ParameterValue
Programming Accuracy (2 nA range)±(0.4% of rdg + 2 pA)
Programming Accuracy (20 nA range)±(0.3% of rdg + 10 pA)
Programming Accuracy (200 nA range)±(0.1% of rdg + 100 pA)
Programming Accuracy (2 µA range)±(0.05% of rdg + 1 nA)
Programming Accuracy (20 µA range)±(0.05% of rdg + 10 nA)
Programming Accuracy (200 µA range)±(0.05% of rdg + 100 nA)
Programming Accuracy (2 mA range)±(0.05% of rdg + 1 µA)
Programming Accuracy (20 mA range)±(0.05% of rdg + 10 µA)
Programming Accuracy (100 mA range)±(0.05% of rdg + 50 µA)

Temperature Coefficient

ParameterValue
Temperature Coefficient (0°C–18°C & 28°C–50°C)±(0.15 × accuracy specification) per °C

Compliance Voltage

ParameterValue
Compliance Voltage Programming Resolution10 mV

Electrical & Power

ParameterValue
Maximum Power Consumption120 VA
Maximum Output Power11 W
Maximum Common Mode Voltage250 V peak

Interfaces & Connectivity

ParameterValue
Digital I/O Port4-bit, RJ-45, 5 V TTL
Trigger Link Connector8-pin micro-DIN
Interlock Connector3-pin micro-DIN
Phase Synchronization ConnectionBNC (Input and Output, 0 to 5 V)

Power

ParameterValue
AC Line Voltage100 V to 240 V AC
AC Line Frequency50 Hz to 60 Hz (automatic sensing)

Inputs & Outputs

ParameterValue
Digital I/O Power Output Voltage+5 V
Digital I/O Power Output Current Limit250 mA

Performance

ParameterValue
Delta Mode CompatibilityKeithley Model 2182 and 2182A Nanovoltmeters
Delta Mode Minimum Cycle Time2.8 ms

Environmental

ParameterValue
Maximum Operating Altitude2000 m

Compliance

ParameterValue
Vibration Standard ComplianceMIL-PRF-28800F Class 3 Random

Technology

Solid State Precision Current Sourcing

Applications

Nanotechnology research, semiconductor characterization, superconductivity measurements, and low-resistance testing