The Keithley 6487 is a 5½-digit picoammeter and voltage source instrument engineered for precision low-current measurements and high-impedance characterization. It measures currents from 20 fA to 20 mA across eight ranges with 10 fA resolution and sources voltage from 200 µV to 505 VDC. The instrument delivers measurement speeds up to 1000 readings per second and incorporates a feedback ammeter architecture that reduces voltage burden to less than 200 µV on lower ranges—enabling accurate measurements in circuits where source voltage is extremely limited. A selectable damping function accommodates capacitive devices, while Alternating Voltage resistance methods extend measurable resistance to 10¹⁶ Ω.
Technical Specifications
• Current Measurement: 20 fA to 20 mA (eight ranges); 10 fA resolution
• Voltage Source: 200 µV to 505 VDC with selectable current limits (2.5 mA, 250 µA, 25 µA, 25 mA depending on range)
• Measurement Speed: Up to 1000 readings per second
• Voltage Burden: <200 µV on lower ranges; 1×10¹¹ Ω in parallel with <1 nF
• Maximum Common Mode Voltage: 505 VDC
• Overload Protection: 500 VDC
• Analog Output: 2V full scale (inverting); <100 Ω impedance
– Key Features
• Eight current measurement ranges with high-speed auto-ranging
• Direct resistance measurement (50 Ω to 5×10¹⁴ Ω) and Alternating Voltage method (up to 10¹⁶ Ω)
• Voltage sweeping capability for device characterization
• Damping function for capacitive load stability
• Feedback picoammeter design reduces ammeter loading effects
– Typical Applications
• Characterization of low-current semiconductor devices and photodiodes
• High-resistance material and surface measurement
• Leakage current analysis in insulators and dielectrics
• Battery and fuel cell testing
– Compatibility & Integration
Analog output supports external data acquisition and control systems. Voltage source common and ammeter common isolation accommodate floating DUT configurations up to 505 VDC.
