6485
Picoammeter
The 5-digit Model 6485 Picoammeter combines
Keithleys expertise in sensitive current measure-
ment instrumentation with enhanced speed and
a robust design . With eight current measurement
ranges and high speed autoranging, this cost-
effective instrument can measure currents from 20fA
to 20mA, taking measurements at speeds up to 1000
readings per second .
The Model 6485s 10fA resolution and superior
sensitivity make it well suited for characterizing low
current phenomena, while its 20mA range lets it
measure currents high enough for applications such
as measuring 4-20mA sensor loops .
Although it employs the latest current measurement
technology, it is significantly less expensive than
other instruments that perform similar functions,
such as optical power meters, competitive pico-
ammeters, or user-designed solutions . With a price thats comparable to a general purpose DMM,
Cost-effective low current
the Model 6485 makes picoamp-level measurements affordable for virtually any laboratory or
measurement solution
p r o duc t ion f lo or .
10fa resolution
l ow Voltage burden and Higher accuracy
5-digit resolution
While DMMs typically employ shunt ammeter circuitry to measure current, the Model 6485 is a feed-
<200V burden voltage
back picoammeter . This design reduces voltage burden by several orders of magnitude, resulting in a
voltage burden of less than 200V on the lower measurement ranges . The low voltage burden makes
up to 1000 readings/second
the Model 6485 function much more like an ideal ammeter than a DMM, so it can make current
measurements with high accuracy, even in circuits with
built-in Model 485 emulation
Model 485 Model 6485
very low source voltages .
mode
Current Ranges 2nA2mA 2nA20mA
200V (1mV on
IEEE-488 and rs -232 interfaces successor to the Model 485 Voltage Burden 200V
20mA range)
Reading Rate 3/s 1000/s
The Model 6485 builds on the strengths of one of
analog output
Digits 4 5
Keithleys most popular picoammeters, the Model 485,
Analog Output Yes Yes
offering an additional 20mA measurement range, as well
Battery Option Yes No
as much higher measurement speeds . With a top speed
Storage Buffer 100 points 2500 points
of up to 1000 readings per second, the Model 6485 is
the fastest picoammeter Keithley has ever made . It offers ten times greater resolution than the Model
485 on every range . A time-stamped 2500-reading data buffer provides minimum, maximum, and
standard deviation statistics . A built-in emulation mode simplifies upgrading existing applications
originally configured with a Model 485 . This emulation mode makes it possible to control the Model
6485 with any custom code written to control the Model 485 . Refer to the comparison table for
additional information .
When do you need a picoammeter?
Measuring low DC currents often demands a lot more than a digital
multimeter (DMM) can deliver. Generally, DMMs lack the sensitivity required
to measure currents less than 100nA. Even at higher currents, a DMMs
input voltage drop (voltage burden) of hundreds of millivolts can make
accurate current measurements impossible. Electrometers can measure
low currents very accurately, but the circuitry needed to measure extremely
low currents, combined with functions like voltage, resistance, and charge
measurement, can increase an electrometers cost signifi cantly. The Model
6485 Picoammeter combines the economy and ease of use of a DMM with
low current sensitivity near that of an electrometer.
1.888.KEITHLEY (U.S. only)
www.keithley.com
A Greater Measure of Confidence
Measures low currents quickly, accurately, and economically
LOW LEVEL MEASURE & SOURCE
Measures low currents quickly, accurately, and economically6485
Picoammeter
f eatures that Expand Test and Measurement f lexibility
ordering Information
Scaled voltage analog output. This output allows the Model 6485 to transmit measurement
results to devices like DMMs, data acquisition boards, oscilloscopes, or strip chart recorders .
6485 Picoammeter
220V overload protection. This high overload protection and a robust design let the Model 6485
accessories supplied
withstand abusive overflows .
CaP-18 Protective shield/
One-touch front panel design. Functions can be configured easily with the push of a button,
Cap (2-lug)
without complicated function menus .
4801 l ow Noise bNC Input
Built-in Trigger Link interface. The Trigger Link interface simplifies synchronizing the Model
Cable, 1.2m (4 ft)
6485 with other instruments and voltage sources . This interface combines six independent
selectable trigger lines on a single connector for simple, direct control over all instruments
in a system .
RS-232 and IEEE-488 interfaces. These interfaces make it easy to integrate the Model 6485 into
automated test and measurement systems .
Display on/off switch. For research on light-sensitive components, such as measuring the dark
currents of photodiodes, the front panel display can be switched off to avoid introducing light that
could significantly reduce the accuracy of the results .
REL and LOG functions. The Model 6485 can make relative readings with respect to a baseline
value or display the logarithm of the absolute value of the measured current .
Resistance calculations. The Model 6485 can calculate resistance by dividing an externally
sourced voltage value by the measured current .
Rear panel BNC inputs. Inexpensive, easy-to-use BNC cables can be employed, rather than more
expensive triax cables .
aPPl ICaTIo Ns
aCCEssor IEs aVaIl abl E sEr VICEs aVaIl abl E
beam monitoring and radiation
6485-3Y-EW 1-year factory warranty extended to 3 years from
monitoring Cabl Es
date of shipment
4802-10 Low Noise BNC Input Cable, 3m (10 ft)
l eakage current testing in C/6485-3Y-ISO 3 (ISO-17025 accredited) calibrations within 3
4803 Low Noise Cable Kit
years of purchase*
insulators, switches, relays, and
7007-1 Shielded IEEE-488 Cable, 1m (3 . 3 ft)
*Not available in all countries
other components
7007-2 Shielded IEEE-488 Cable, 2m (6 . 6 ft)
7007-4 Shielded IEEE-488 Cable, 4m (13 . 1 ft)
sEM beam current
7009-5 RS-232 Cable
measurements
7754-3 BNC to Alligator Cable, 0 . 9m (3 ft)
Galvanic coupling
8607 Banana Cable set for Analog Output
measurements
8501-1 Trigger Link Cable with Male Micro-DIN Connectors at
each End, 1m (3 . 3 ft)
o ptoelectronic device testing
8501-2 Trigger Link Cable with Male Micro-DIN Connectors at
and characterization
each End, 2m (6 . 6 ft)
8503 DIN-to-BNC Trigger Cable
o ptical fiber alignment
aDaPTErs
Circuit test and analysis in
CS-565 BNC Barrel
DCl f circuits
7078-TRX-BNC Female BNC to 3-Slot Male Triax for connecting
BNC cable into triax fixture
sensor characterization
r aCK Mou NT KITs
I-V measurements of 4288-1 Single Fixed Rack Mounting Kit
semiconductors and other 4288-2 Dual Fixed Rack Mounting Kit
devices
GPIb INTErfa CEs
KPCI-488LPA IEEE-488 Interface/Controller for the PCI Bus
Nanoelectronic device
KUSB-488B IEEE-488 USB-to-GPIB Interface Adapter
characterization
Capacitor leakage
Teaching labs
1.888.KEITHLEY (U.S. only)
www.keithley.com
A Greater Measure of Confidence
Measures low currents quickly, accurately, and economically
LOW LEVEL MEASURE & SOURCE
Measures low currents quickly, accurately, and economically