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LOW LEVEL MEASURE & SOURCE www.keithley.com 1.888.KEITHLEY (U.S. only) A Greater Measure of Confidence

  • C ost-effective low current measurement solution
  • 1 0fa r esolution
  • 5 ½-digit resolution
  • < 200µV burden voltage
  • up t o 1000 readings/second
  • bu ilt-in Model 485 emulation mode
  • I EEE-488 and rs- 232 interfaces
  • ana log output The 5½-digit Model 6485 Picoammeter combines Keithley’s 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 T he Model 6485’s 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 A lthough 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 a mmeters, or user-designed solutions . With a price that’s comparable to a general purpose DMM, the Model 6485 makes picoamp-level measurements affordable for virtually any laboratory or production floor . lo w Voltage bu rden and Higher ac curacy While DMMs typically employ shunt ammeter circuitry to measure current, the Model 6485 is a feed - back picoammeter . This design reduces voltage burden by several orders of magnitude, resulting in a voltage burden of less than 200µV on the lower measurement ranges . The low voltage burden makes 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 very low source voltages su ccessor to the Model 485 The Model 6485 builds on the strengths of one of Keithley’s most popular picoammeters, the Model 485, offering an additional 20mA measurement range, as well as much higher measurement speeds With a top speed 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 . Model 485 Model 6485 Current Ranges 2nA–2mA 2nA–20mA Voltage Burden 200µV 200µV (1mV on 20mA range) Reading Rate 3/s 1000/s Digits 4½ 5½ Analog Output Yes Yes Battery Option Yes No Storage Buffer 100 points 2500 points 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 DMM’s 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 electrometer’s cost signifi c antly. The Model

6485 Picoammeter combines the economy and ease of use of a DMM with

low current sensitivity near that of an electrometer.

6485 Picoammeter

Measures low currents quickly, accurately, and economically Measures low currents quickly, accurately, and economically

LOW LEVEL MEASURE & SOURCE A Greater Measure of Confidence www.keithley.com 1.888.KEITHLEY (U.S. only) fe atures that Expand Test and Measurement fl exibility

  • S caled 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 .
  • 2 20V overload protection. This high overload protection and a robust design let the Model 6485 withstand abusive overflows
  • O ne-touch front panel design. Functions can be configured easily with the push of a button, without complicated function menus .
  • B uilt-in Trigger Link interface. The Trigger Link interface simplifies synchronizing the Model 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 .
  • R S-232 and IEEE-488 interfaces. These interfaces make it easy to integrate the Model 6485 into automated test and measurement systems .
  • D isplay 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
  • R EL 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
  • R esistance calculations. The Model 6485 can calculate resistance by dividing an externally sourced voltage value by the measured current
  • R ear panel BNC inputs. Inexpensive, easy-to-use BNC cables can be employed, rather than more expensive triax cables .aPP lI C aT I oNs
  • be am monitoring and radiation monitoring
  • le akage current testing in insulators, switches, relays, and other components
  • sE M beam current measurements
  • G alvanic coupling measurements
  • op toelectronic device testing and characterization
  • op tical fiber alignment
  • C ircuit test and analysis in DCl f circuits
  • se nsor characterization
  • I -V measurements of semiconductors and other devices N anoelectronic device characterization
  • C apacitor leakage
  • T eaching labs or dering Information

a ccessories s upplied CaP -18 P rotective sh ield/ Cap (2-lug) 4801 l o w Noise bN C Input Cable, 1.2m (4 ft) aC CE ssorI E s aVaIl ablE CablEs 4802-10 L ow Noise BNC Input Cable, 3m (10 ft) 4803 L ow Noise Cable Kit 7007-1 S hielded IEEE-488 Cable, 1m (3 .3 f 7007-2 S hielded IEEE-488 Cable, 2m (6 .6 f 7007-4 S hielded IEEE-488 Cable, 4m (13 .1 f 7009-5 R S-232 Cable 7754-3 B NC to Alligator Cable, 0 .9 m (3 ft) 8607 B anana Cable set for Analog Output 8501-1 T rigger Link Cable with Male Micro-DIN Connectors at each End, 1m (3 .3 f 8501-2 T rigger Link Cable with Male Micro-DIN Connectors at each End, 2m (6 .6 f 8503 D IN-to-BNC Trigger Cable aDa PTE rs CS-565 B NC Barrel 7078-TRX-BNC F emale BNC to 3-Slot Male Triax for connecting BNC cable into triax fixture raCK MouNT K ITs 4288-1 S ingle Fixed Rack Mounting Kit 4288-2 D ual Fixed Rack Mounting Kit GPIb INTE rfaCEs KPCI-488LPA I EEE-488 Interface/Controller for the PCI Bus KUSB-488B I EEE-488 USB-to-GPIB Interface Adapter sEr VICEs aVaIl ablE 6485-3Y-EW 1 -year factory warranty extended to 3 years from date of shipment C/6485-3Y-ISO 3 ( ISO-17025 accredited) calibrations within 3 years of purchase* *Not available in all countries Measures low currents quickly, accurately, and economically Measures low currents quickly, accurately, and economically

LOW LEVEL MEASURE & SOURCE www.keithley.com 1.888.KEITHLEY (U.S. only) A Greater Measure of Confidence GENEral INPUT CONNECTOR: BNC on rear panel . DI SPLAy: 1 2 character vacuum fluorescent . R ANGING: Automatic or manual . O VERRANGE INDICATION: Display reads “OVRFLOW .” C ONVERSION TIME: Selectable 0 1 PLC to 60 PLC (50 PLC under 50Hz operation) . (Adjustable from 200µs to 1s) READING RATE: To internal buffer: 000 readings/second 1 To IEEE-488 bus: 00 readings/second 1, 2 Notes: 1 . 0 .0 1 PLC, digital filters off, front panel off, auto zero off . 2 . Binary transfer mode . IEEE-488 .1 . B UFFER: Stores up to 2500 readings . P ROGRAMS: Provide front panel access to IEEE address, choice of engineering units or scientific notation, and digital calibration EMC: Conforms with European Union Directive 89/336/EEC, EN61326-1 . S AFET y: C onforms with European Union Directive 73/23/EEC, EN61010-1 . T RIGGER LINE: Available, see manual for usage . D IGITAL FILTER: Median and averaging (selectable from 2 to 100 readings) . EN VIRONMENT: Operating: 0°–50°C; relative humidity 70% non-condensing, up to 35°C . Above 35°C, derate humidity by 3% for each °C . St orage: –25° to +65°C . W ARM-UP: 1 hour to rated accuracy (see manual for recommended procedure) . P OWER: 100–120V or 220–240V, 50–60Hz, 30VA . P HySI CAL: Case Dimensions: 90mm high × 214mm wide × 369mm deep (3 ½ in . × 83 ⁄8 in . × 149 ⁄16 in . ) . Working Dimensions: From front of case to rear including power cord and IEEE-488 con - nector: 394mm (15 .5 i n) . N et Weight: <2 .8 k g (<6 .1 l bs) . S hipping Weight: <5 kg (<11 lbs) . IEEE-488 bus IMPl EMENTaTI o N MULTILINE COMMANDS: DCL, LLO, SDC, GET, GTL, UNT, UNL, SPE, SPD . IM PLEMENTATION: SCPI (IEEE-488 .2 , SCPI-1996 .0 ); DDC (IEEE-488 .1 ) . UN ILINE COMMANDS: IFC, REN, EOI, SRQ, ATN I NTERFACE FUNCTIONS: SH1, AH1, T5, TE0, L4, LE0, SR1, RL1, PP0, DC1, DT1, C0, E1 . P ROGRAMMABLE PARAMETERS: Range, Zero Check, Zero Correct, EOI (DDC mode only), Trigger, Terminator (DDC mode only), Calibration (SCPI mode only), Display Format, SRQ, REL, Output Format, V-offset Cal A DDRESS MODES: TALK ONLY and ADDRESSABLE . L ANGUAGE EMULATION: Keithley Model 485 emulation via D DC m ode . R S-232 IMPLEMENTATION: Supports: SCPI 1996 .0 . Baud Rates: 300, 600, 1200, 2400, 4800, 9600, 19 .2 k, 38 .4 k, 57 .6 k . Protocols: Xon/Xoff, 7 or 8 bit ASCII, parity-odd/even/none . Connector: DB-9 TXD/RXD/GND . 5½ Digit ac curacy ( 1 Year) 1 ana log D efault ± (% rdg. + o ffset) T ypical r i se Time 3 r a nge r e solution 1 8°–28°C, 0–70% rH r Ms Noise 2 ( 10% to 90%) 2 n A 1 0 f A 0 .4 % + 4 00 fA 2 0 f A 8 m s n A f A 0 .4 % + 1 p A f A m s n A p A 0 .2 % + 0 pA p A µ s µ A p A 0 .1 5% + 00 pA p A µ s µ A p A 0 .1 % + 1 n A p A µ s µ A n A 0 .1 % + 0 nA n A µ s m A n A 0 .1 % + 00 nA n A µ s m A n A 0 .1 % + 1 µ A n A µ s TEMPERATURE COEFFICIENT: 0°–18°C & 2 8°–50°C . For each °C, add 0 .1 × (% rdg + offset) to accuracy spec IN PUT VO LTAGE BU RDEN: <200µV on all ranges except <1mV on 20mA r ange . MA XIMUM IN PUT CA PACITANCE: S table to 10nF on all nA ranges and 2µA r ange; 1µF on 20µA and 200µA ranges, and on mA r anges . M AXIMUM COMMON MODE VOLTAGE: 42V M AXIMUM CO NTINUOUS IN PUT VOLTAGE: 220 VDC . I SOLATION (Meter COMMON to chassis): Typically >5 ×1011W in parallel with <1nF . N MRR1 (50 or 60Hz): 60dB . A NALOG OUTPUT: Scaled voltage output (inverting 2V full scale on all ranges) 3% ±2mV, 1k W impedance . NoT E s 1 . A t 1 PLC – limited to 60 rdgs/second under this condition . 2 . A t 6 PLC, 1 standard deviation, 100 readings, filter off, capped input – limited to 10 rdgs/sec under this condition . 3 . M easured at analog output with resistive load >100k W .