6220 DC Current Source
6221 AC and DC Current Source
6220 and 6221
• Source and sink (programmable
load) 100fA to 100mA
14
• 10
Ω output impedance ensures
stable current sourcing into
variable loads
• 65000-point source memory
allows executing comprehensive
test current sweeps directly from
the current source
• Built-in RS-232, GPIB, Trigger
Link, and digital I/O interfaces
• Reconfigurable triax output
simplifies matching the
application's guarding
requirements
• Model 220 emulation mode
eliminates need to reprogram
existing applications
• Instrument control software
available for both Macintosh
and PC controllers
6221 Only
• Source AC currents from 1pA to
100mA for AC characterization
of components and materials.
The 6221’s 10MHz output
update rate generates smooth
sine waves up to 100kHz
• Built-in standard and arbitrary
waveform generators with 1mHz
to 100kHz frequency range.
Applications include use as a
complex programmable load or
sensor signal and for noise
emulation
• Programmable pulse widths as
short as 5µs, limiting power
dissipation in delicate components. Supports pulsed I-V
measurements down to 50µs
when used with Model 2182A
Nanovoltmeter
• Built-in Ethernet interface for
easy remote control without a
GPIB controller card
The Model 6220 DC Current Source and Model 6221 AC and DC Current Source combine ease of
use with exceptionally low current noise. Low current sourcing is critical to applications in test environments ranging from R&D to production, especially in the semiconductor, nanotechnology, and
superconductor industries. High sourcing accuracy and built-in control functions make the Models
6220 and 6221 ideal for applications like Hall measurements, resistance measurements using delta
mode, pulsed measurements, and differential conductance measurements.
The need for precision, low current sourcing.
Device testing and characterization for today's very
small and power-efficient electronics requires sourcing low current levels, which demands the use of
a precision, low current source. Lower stimulus currents produce lower—and harder to measure—
voltages across the device. Combining the Model 6220 or 6221 with a Model 2182A Nanovoltmeter
makes it possible to address both of these challenges.
AC current source and current source waveform generator. The Model 6221 is the only AC current source on the market. Before its introduction, researchers and engineers were forced to build
their own AC current sources. This cost-effective source provides better accuracy, consistency, reliability, and robustness than “home-made” solutions. The Model 6221 is also the only commercially available current source waveform generator, which greatly simplifies creating and outputting complex
waveforms.
Simple programming. Both current sources are fully programmable via the front panel controls or
from an external controller via RS-232 or GPIB interfaces; the Model 6221 also features an Ethernet
interface for remote control from anywhere there’s an Ethernet connection. Both instruments can
source DC currents from 100fA to 105mA; the Model 6221 can also source AC currents from 1pA to
100mA. The output voltage compliance of either
source can be set from 0.1V to 105V in 10mV
steps. Voltage compliance (which limits the
amount of voltage applied when sourcing a current) is critical for applications in which overvoltages could damage the device under test
(DUT).
Drop-in replacement for the Model 220
current source. These instruments build upon
Keithley’s popular Model 220 Programmable
Current Source; a Model 220 emulation mode
makes it easy to replace a Model 220 with a
Model 6220/6221 in an existing application without rewriting the control code.
Define and execute current ramps easily.
Both the Models 6220 and 6221 offer tools for
defining current ramps and stepping through
predefined sequences of up to 65,536 output
TYPICAL APPLICATIONS
• Nanotechnology
- Differential conductance
- Pulsed sourcing and resistance
• Optoelectronics
- Pulsed I-V
• Replacement for AC resistance
bridges (when used with Model
2182A)
- Measuring resistance with low
• Replacement for lock-in amplifiers (when used with Model
2182A)
- Measuring resistance with low
values using a trigger or a timer. Both sources
Precision low current sourcing
power
noise
1.888.KEITHLEY (U.S. only)
www.keithley.com
A GREATER MEASURE OF CONFIDENCE
LOW LEVEL MEASURE & SOURCE
201
6220 DC Current Source
6221 AC and DC Current Source
Ordering Information
6220 DC Precision Current
6221 AC and DC Current
6220/2182A
6221/2182A
Extended warranty, service, and
calibration contracts are available.
Precision low current sourcing
Accessories Supplied
237-ALG-2
8501-2 6.6 ft (2m) Trigger Link
CA-180-3A
CA-351A
CS-1195-2
Instruction manual on CD
Getting Started manual (hardcopy)
Software
7078-TRX-5 5ft (1.5m), Low Noise, Triax-to-Triax Cable
7006-* GPIB Cable with Straight-On Connector
Source
Source
Complete Delta Mode
System, w/DC Current
Source, Nanovoltmeter,
and all necessary cables
(GPIB cables not
included)
Complete Delta Mode
System, w/AC and DC
Current Source, Nanovoltmeter, and all necessary cables (GPIB cables
not included)
6.6 ft (2m), Low Noise,
Input Cable with Triaxto-Alligator Clips
Cable to connect 622x to
2182A
Ethernet Crossover
Cable (6221 only)
Communication Cable
between 2182A and
622x
Safety Interlock
Connector
ACCESSORIES AVAILABLE
(Male on Both Ends)
support linear, logarithmic, and custom sweeps. The Model 6221’s combination of high source resolution and megahertz update rates makes it capable of emulating high fidelity current signals that are
indistinguishable from analog current ramps.
Free Instrument Control Start-up Software
The instrument control software provided with the sources simplifies both performing basic sourcing
tasks and coordinating complex measurement functions with the Keithley Model 2182A. Both
Macintosh- and PC-compatible versions of the software are supplied. The software, developed in the
™
LabVIEW
programming environment, includes a step-by-step measurement guide that helps users
set up their instruments and make proper connections, as well as program basic sourcing functions.
The advanced tools in the package support delta mode, differential conductance, and pulse mode
measurements. From this package, users can print out the instrument commands for any of the preprogrammed functions, which provides a starting point for incorporating these functions into customized applications.
Differential Conductance
Differential conductance measurements are among the most important and critical measurements
made on non-linear tunneling devices and on low temperature devices. Mathematically, differential
conductance is the derivative of a device’s I-V curve. The Model 6220 or 6221, combined with the
Model 2182A Nanovoltmeter, is the industry’s most complete solution for differential conductance
measurements. Together, these instruments are also the fastest solution available, providing 10× the
speed and significantly lower noise than other options. Data can be obtained in a single measurement pass, rather than by averaging the result of multiple sweeps, which is both time-consuming and
prone to error. The Model 622X and Model 2182A are also easy to use because the combination can
be treated as a single instrument. Their simple connections eliminate the isolation and noise current
problems that plague other solutions.
Figure 1. Perform, analyze, and display differential conductance measurements.
Delta Mode
Keithley originally developed the delta mode method for making low noise measurements of voltages
and resistances for use with the Model 2182 Nanovoltmeter and a triggerable external current
source. Essentially, the delta mode automatically triggers the current source to alternate the signal
polarity, then triggers a nanovoltmeter reading at each polarity. This current reversal technique cancels out any constant thermoelectric offsets, ensuring the results reflect the true value of the voltage.
This same basic technique has been incorporated into the Model 622X and Model 2182A delta mode,
but its implementation has been dramatically enhanced and simplified. The technique can now
cancel thermoelectric offsets that drift over time, produce results in half the time of the previous
technique, and allow the source to control and configure the nanovoltmeter, so setting up the
202
1.888.KEITHLEY (U.S. only)
LOW LEVEL MEASURE & SOURCE
www.keithley.com
A GREATER MEASURE OF CONFIDENCE
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