Picoammeter combines 500 V source with femtoamp resolution.
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Press Release Summary:
Model 6487 Picoammeter/Voltage Source can apply voltage stimulus as high as 500 V to device under test and measure currents as low as 20 fA. It also provides direct readout of resistance measurements up to 5x1016 ohms and offers 5½ digit resolution and voltage burden of less than 200 µV on lower measurement ranges. Voltage source ranges are ±10, ±50, and ±500 Vdc, with basic accuracy of ±0.1% on programmed value.
Original Press Release:
Keithley Picoammeter Combines 500V Source and Femtoamp Resolution with Robustness, Speed, and Economy
CLEVELAND-October 21, 2002-Keithley Instruments, Inc. (NYSE: KEI) today introduced its Model 6487 Picoammeter/Voltage Source, providing a set of measurement capabilities unique in the industry. These include low current sensitivity near that of an electrometer, with ease of use and pricing comparable to a high performance DMM. The Model 6487 is a 5-1/2-digit instrument that can apply a voltage stimulus as high as 500V to a device under test (DUT) and measure currents as low as 20fA. It also provides direct readout of resistance measurements up to 5x1016 ohms using the source voltage, measure current method, including an alternating voltage method to minimize background current errors. With a data acquisition rate of 1000 readings/s into buffer memory, there is no faster picoammeter available. These features result in the most cost-effective solution available for applications such as ion beam current measurements, radiation monitoring, characterization of optoelectronic and semiconductor devices, optical fiber alignment, and high resistance material screening.
Application Background. There is a growing need for low DC current measurements on materials and devices that also require stimulation by a voltage source. Typical measurements include insulation resistance, leakage currents, photodiode and photomultiplier tube currents, SEM beam currents, sensor characterization, and I-V characterization of semiconductors and other components. The Model 6487 will also be of interest to OEMs and system integrators who require voltage stimulated low-level current measurements in their test systems.
The ability of the Model 6487 to measure currents less than 100nA accurately is something that even high performance DMMs cannot do because of sensitivity, voltage burden, and cabling
limitations. While electrometers (a more sensitive class of instrument) can measure low currents very accurately, their versatility and extremely high precision circuitry increases their cost significantly. The Model 6487 is significantly less expensive than other instruments that performn similar functions, such as optical power meters, tera-ohmmeters, user-designed solutions, and competitive products with fewer functions.
Model 6487 Product Details. The Model 6487's 20fA sensitivity allows characterizing low current phenomena, while its 20mA range lets it measure currents high enough for 4-20mA sensor loops. Its 5-1/2-digit resolution and voltage burden of less than 200µV on lower measurement ranges allow highly accurate measurements, even in circuits with low source voltages. A built-in Keithley Model 487 emulation mode simplifies upgrading existing applications. Furthermore, the Model 6487 can take abusive overloads up to 505VDC (maximum common mode and continuous input). It is even safe to short the voltage-source into the picoammeter.
The voltage source ranges are ±10, ±50, and ±500VDC, with a basic accuracy of ±0.1% on the programmed value. In addition, an alternating voltage method for high resistance measurements
is available that reduces errors due to externally generated background currents. For all measurements, a time-stamped 3000-reading data buffer provides minimum, maximum, and standard deviation statistics. A REL function permits making relative readings with respect to a baseline value; the LOG function displays the logarithm of the absolute value of the measured
current.
The Model 6487 is designed for easy connection to other instruments and voltage sources with a built-in Trigger Link interface that allows synchronizing two or more instruments. This interface combines six independent selectable trigger lines on a single connector for simple, direct control over all instruments in a system. An EEEE-488 interface is included for controlling the instrument with a PC over the GPEB bus. There also is an RS-232 interface. The Model 6487 has triaxial
connectors that allow the picoammeter to be used in floating operation up to 500V, but inexpensive BNC cables can be used when appropriate.
To simplify integrating the Model 6487 into PC-based test systems, the instrument comes with Keithley's ExceLINX, an add-in utility for Microsoft8 Excel. Within minutes of installing
ExceLINX on a PC. users can acquire data directly from the Model 6487 instrument, and then employ Excel's graphics, charting, and analysis capabilities to tum that data into useful information. No programming is required to use ExceLINX-a few mouse clicks are all it takes. Keithley also provides a 6487 instrument driver for use with Application Development Environments such as LabVIEWT, LabWindows(TM)/CVI, Visual Basic*, C/C++, and TestPoint(TM). Numerous examples and an online help utility are provided to help programmers get their applications "Up & Running" quickly.
Additional features include:
o Scaled voltage analog output. This allows the Model 6487 to transmit measurement results to devices like DMMs, data acquisition cards, oscilloscopes, or strip chart recorders.
o One-touch front panel design. Functions can be configured easily with the push of a button, without complicated function menus.
o Display on/off switch. For research on light-sensitive components, such as photodiodes, the front panel display can be switched off to avoid introducing light that could significantly reduce the accuracy of dark current measurements.
o Digital I/O. Versatile control of component handlers and other instruments is possible with the Model 6487's digital I/O capabilities.
Price and Availability. The Model 6487 is available immediately at a list price of $2995.
For More Information. For more information on the Model 6487, or any of Keithley's test and measurement solutions, contact Keithley Instruments at:
Telephone: 888-534-8453 or 440-248-0400
FAX: 440-248-6168
E-mail: product infogkeithley.com
Internet: www.keithley.com
Address: Keithley Instruments, Inc.
28775 Aurora Road
Cleveland, OH 44139-1891
About Keithley Instruments. Keithley Instruments, Inc. provides optical and electrical measurement solutions from DC to RF (radio frequency) to the wireless, semiconductor, optoelectronics, and other electronics manufacturing industries. Engineers and scientists around the world use Keithley's advanced hardware and software for process monitoring, production test, and basic research.
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