The Keithley 6485 is a 5½-digit picoammeter designed to measure low currents with high sensitivity and speed. It offers eight current measurement ranges from 2 nA to 20 mA, making it ideal for characterizing optoelectronic components, testing sensors, and performing basic low-current measurements.

Specifications

General

ParameterValue
Display5½-digit vacuum fluorescent display (VFD)

Physical

ParameterValue
Operating Temperature0 °C to 50 °C
Weight2.8 kg

Measurement Specifications

ParameterValue
Measurement Ranges2 nA, 20 nA, 200 nA, 2 µA, 20 µA, 200 µA, 2 mA, 20 mA
Display Resolution5½ digits
Maximum Resolution10 fA
DC Current Accuracy (2 nA Range)±(0.4% + 400 fA)
DC Current Accuracy (20 nA Range)±(0.4% + 1 pA)
DC Current Accuracy (200 nA Range)±(0.2% + 10 pA)
DC Current Accuracy (2 µA Range)±(0.15% + 100 pA)
DC Current Accuracy (20 µA Range)±(0.1% + 1 nA)
DC Current Accuracy (200 µA Range)±(0.1% + 10 nA)
DC Current Accuracy (2 mA Range)±(0.1% + 100 nA)
DC Current Accuracy (20 mA Range)±(0.1% + 1 µA)
Temperature Coefficient0.1 × (specified accuracy) per °C (for 0 °C to 18 °C and 28 °C to 50 °C)

Input Characteristics

ParameterValue
Maximum Overload Input Voltage (Continuous)220 V peak
Isolation (Input Common to Chassis)500 V peak

System Performance and Triggering

ParameterValue
Maximum Reading Rate (Internal Buffer)1000 readings/s
Maximum Reading Rate (over GPIB)900 readings/s
Internal Buffer Size2500 readings
Digital Filter ConfigurationsMedian (1 to 10 readings), Average (1 to 100 readings, repeat or moving)

Connectivity and Control

ParameterValue
GPIB InterfaceIEEE-488.2
Trigger Link Connector Type8-pin micro-DIN
Command Set CompatibilitySCPI-1996
Emulation ModesKeithley 485

Power and Electrical

ParameterValue
AC Line Voltage Input Range100 V to 240 V AC
AC Line Frequency Range50 Hz to 60 Hz
Power Consumption30 VA maximum

Physical Characteristics

ParameterValue
Rack Unit Size2U half-rack
Dimensions with Bumpers (W x H x D)238 mm × 104 mm × 370 mm

Environmental and Safety

ParameterValue
Storage Temperature Range-25 °C to 65 °C
Operating Altitude Limit2000 m
Warm-up Time1 hour
EMC/RFI StandardsEN 61326-1
CE Mark StatusYes

Accessories and Calibration

ParameterValue
Optional Shielded Cables4801 Low-Noise BNC Input Cable
Optional Rack Mount Kits4288-1 (single), 4288-2 (dual)
Calibration Interval1 year

Instrument Features

ParameterValue
Zero Check FunctionSelectable on/off, redirects input current to ground for safe connection and zeroing

Interfaces

ParameterValue
Trigger Link Channels6 independent channels

Control & Software

ParameterValue
Programming LanguageSCPI (Standard Commands for Programmable Instruments)

Measurement Control

ParameterValue
Measurement RangingAutomatic or manual

Technology

Analog-to-digital measurement

Applications

Low current measurement, photodiode characterization, fiber optic testing, component testing