Datasheet

LOW LEVEL MEASURE & SOURCE
www.keithley.com
1.888.KEITHLEY
(U.S. only)
A Greater Measure of Confidence
6514
Programmable Electrometer
V
SOURCE
+
–
A/D
R
V
BURDEN
= 200mV at
full range
Desired Current Reading: I =
V
SOURCE
R
DMM’s Actual Current Reading: I =
V
SOURCE
– V
BURDEN
R
DMM
I
Figure 3. Errors Due to Burden Voltage when Measuring with a DMM
VOLTS Accuracy Temperature
(1 Year)
1
Coefficient
5 ½ -Digit 18°–28°C 0°–18°C & 28°–50°C
Range Resolution ±(%rdg+counts) ±(%rdg+counts)/°C
2 V 10 µV 0.025 + 4 0.003 + 2
20 V 100 µV 0.025 + 3 0.002 + 1
200 V 1 mV 0.06 + 3 0.002 + 1
NOTES
1. When properly zeroed, 5½-digit. Rate: Slow (100ms integration time).
NMRR: 60dB on 2V, 20V, >55dB on 200V, at 50Hz or 60Hz ±0.1%.
CMRR: >120dB at DC, 50Hz or 60Hz.
INPUT IMPEDANCE: >200TW in parallel with 20pF, <2pF guarded (10MW with zero check on).
SMALL SIGNAL BANDWIDTH AT PREAMP OUTPUT: Typically 100kHz (–3dB).
AMPS Accuracy Temperature
(1 Year)
1
Coefficient
5 ½ -Digit 18°–28°C 0°–18°C & 28°–50°C
Range Resolution ±(%rdg+counts) ±(%rdg+counts)/°C
20 pA 100 aA
2
1 + 30 0.1 + 5
200 pA 1 fA
2
1 + 5 0.1 + 1
2 nA 10 fA 0.2 + 30 0.1 + 2
20 nA 100 fA 0.2 + 5 0.03 + 1
200 nA 1 pA 0.2 + 5 0.03 + 1
2 µA 10 pA 0.1 + 10 0.005 + 2
20 µA 100 pA 0.1 + 5 0.005 + 1
200 µA 1 nA 0.1 + 5 0.005 + 1
2 mA 10 nA 0.1 + 10 0.008 + 2
20 mA 100 nA 0.1 + 5 0.008 + 1
NOTES
1. When properly zeroed, 5½-digit. Rate: Slow (100ms integration time).
2. aA =10
–18
A, fA=10
–15
A.
INPUT BIAS CURRENT: <3fA at T
CAL
(user adjustable). Temperature coefficient = 0.5fA/°C.
INPUT BIAS CURRENT NOISE: <750aA p-p (capped input), 0.1Hz to 10Hz bandwidth, damping
on. Digital filter = 40 readings.
INPUT VOLTAGE BURDEN at T
CAL
±1°C (user adjustable):
<20µV on 20pA, 2nA, 20nA, 2µA, 20µA ranges.
<100µV on 200pA, 200nA, 200µA ranges.
<2mV on 2mA range.
<4mV on 20mA range.
TEMPERATURE COEFFICIENT OF INPUT VOLTAGE BURDEN: <10µV/°C on pA, nA, µA ranges.
PREAMP SETTLING TIME (to 10% of final value): 2.5s typical on pA ranges, damping off, 3s typi-
cal on pA ranges damping on, 15ms on nA ranges, 5ms on µA and mA ranges.
NMRR: >95dB on pA, 60dB on nA, µA, and mA ranges at 50Hz or 60Hz ±0.1%. Digital Filter = 40.
OHMS
Ac cu ra cy Temperature
(1 Year)
1
Coefficient Test
5
½ -Digit 18°–28°C 0°–18°C & 28°–50°C Current
R
ange Resolution ±(% rdg+counts) ±(% rdg+counts)/°C (nominal)
2 kW 10 mW 0.20 + 10 0.01 + 2 0.9 mA
20 kW 100 mW 0.15 + 3 0.01 + 1 0.9 mA
200 kW 1 W 0.25 + 3 0.01 + 1 0.9 mA
2 MW 10 W 0.25 + 4 0.02 + 2 0.9 µA
20 MW 100 W 0.25 + 3 0.02 + 1 0.9 µA
200 MW 1 kW 0.30 + 3 0.02 + 1 0.9 µA
2 GW 10 kW 1.5 + 4 0.04 + 2 0.9 nA
20 GW 100 kW 1.5 + 3 0.04 + 1 0.9 nA
200 GW 1 MW 1.5 + 3 0.04 + 1 0.9 nA
NOTES
1. When properly zeroed, 5½-digit. Rate: Slow (100ms integration time).
MAXIMUM OPEN CIRCUIT VOLTAGE: 250V DC.
PREAMP SETTLING TIME (To 10% of final reading with <100pF input capacitance): 2kW
through 200kW: 2ms; 20MW through 200MW: 90ms. 2GW through 200GW: 1s.
The example below compares a DMM’s voltage burden errors with
the 6514’s.
DMM Offset Currents
Typically, offset currents in DMMs are tens or hundreds of picoamps,
which severely limits their low current measuring capabilities compared to
the Model 6514 with 3fA input bias current.
If:
The desired current reading is: I =
1V
50kW
= 20µA
V
SOURCE
= 1V, R = 50kW
Actual Reading
(20µA range
on DMM):
I =
1V – 200mV
50kW
=
800mV
50kW
= 16µA = 20% Burden error
with a DMM
V
BURDEN
= 200mV
6514 Actual Reading:
I =
0.999990V
50kW
= 19.9998µA = 0.001% Burden error
with the 6514
V
BURDEN
= 10µV
Refer to Figure 3.
Refer to Figure 2.
APPLICATIONS
• High resistivity measurements
• Leakage currents
• Ion selective electrode
measurements
• pH measurements
• Conductivity cells
• Potentiometry
Model 6514 specifications Model 6514 specifications