Voltage Controlled Current Source
CS580— Current source

CS580 Current Source· 1 nA/V to 50 mA/V gain

The Model CS580 Voltage Controlled Current Source createsa new capability for researchers needing ultra-low current
noise in a flexible, easy to use instrument. The CS580 isa natural companion product for use with sensitive ACinstruments such as lock-in amplifiers, providing a straightforward method for generating precision low-noise currents
directly from an AC or DC control voltage. Current isboth sourced and sinked with adjustable compliance voltage
up to ±50 V, giving full “four-quadrant” performance. TheCS580 is a welcome addition to any research lab studying
semiconductors and transport phenomena, superconductivity,and nanotechnology, to name just a few.

· Up to 200 kHz bandwidth

Ultra-Low Noise Design· Low thermal drift

With up to ±50 V compliance voltage, the CS580 can sourceand sink precision AC and DC currents from 100 fA to 100 mA.
The CS580’s ultra-low noise design takes advantage of thebest transistors, op-amps, and discrete components available
combined with careful high impedance board layout toachieve the highest performance possible. The design evenfeatures linear power supplies rather than switching power
supplies, so switching frequency interference can never bea problem.

· AC and DC current source· Sources/sinks current - true fourquadrant operation· Current from 100 fA to 100mA· ±50 V compliance voltage· RS-232 and optical fiber interfaces

An actively driven guard provides the greatest bandwidth(up to 200 kHz) and lowest possible leakage current. There’s
also a buffered monitor output for high impedance voltage
measurements.

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CS580 Voltage Controlled Current Source

CPU Clock Stopping Architecture
Front-panel instrument configuration is managed by amicrocontroller whose system clock only oscillates during
the brief moments needed to change instrument settings. The
drive electronics are completely static, with no “scanning” orrefresh to generate the slightest interference.
Whenever the microcontroller becomes active, the “CPUActivity” indicator illuminates, clearly showing when thedigital clock is running. This occurs in response to front-panel
button presses or remote computer commands. But when the
microcontroller is not active, there is absolutely no digitalinterference at all.
RS-232 and Optical Fiber Interfaces

CS580 front panel

There is an RS-232 computer interface on the rear panel of theCS580. All functions of the instrument can be set or read via
the interface. When sending commands to the instrument, theCS580’s microcontroller will be activated, and digital noise
may be present.
For remote interfacing with complete electrical isolation,
the CS580 also has a rear-panel fiber optic interface. Whenconnected to the SX199 Remote Computer Interface Unit,a path for controlling the CS580 via GPIB, Ethernet, andRS-232 is provided.

Ordering Information
CS580
SX199

Voltage controlled current source
Remote computer interface unit

CS580 rear panel

CS580 Specifications
Remote Interfaces

OutputCompliance voltage
Compliance error
DC output resistance
Output capacitance
Guard output
Output power
THD
Output connector
CM voltage
CM isolation

0 to 50 V (bipolar)
0.5 % + 50 mV
1012 Ω (1 nA/V gain)<12 pF (filter off), <500 pF (filter on)–50 V to +50 V, 5 kΩ internal resistance
5 W (four quadrant sourcing/sinking)0.01 % typ.
3-lug Triax for current output. Banana
jacks for load voltage monitoring
250 Vrms (DC to 60 Hz)>1 GΩ, <1 nF

Input
Input range
Input impedance
Input connector–2 V to +2 V
100 kΩ
BNC

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RS-232
Optical fiber

DB-9 connector, 9600 baud
Connection to SX199 Optical Interface
Controller. Provides connectivity toGPIB, RS-232 and Ethernet

GeneralOperating temperature 0 °C to 40 °C, non-condensing
Power<30 W, 100/120/220/240 VAC,
50 Hz or 60 Hz
Dimensions
8.3” × 3.5” × 13” (WHD)
Weight15 lbs.
WarrantyOne year parts and labor on defects inmaterials and workmanshipCS580 Specifications

BNC analog input (AC & DC)
Gain

Max Output

Gain
accuracy

Bandwidth(0 Ω load, typ.)

1 nA/V
10 nA/V
100 nA/V
1 µA/V
10 µA/V
100 µA/V
1 mA/V
10 mA/V
50 mA/V

2.2 nA
22 nA
220 nA
2.2 µA
22 µA
220 µA
2.2 mA
22 mA
110 mA

1.2 %
1.2 %
1.2 %
0.5 %
0.5 %
0.5 %
0.5 %
0.5 %
1%

5 kHz
10 kHz
20 kHz75 kHz150 kHz150 kHz150 kHz200 kHz150 kHz

Gain drift
OffsetOffset drift

200 ppm/°C
3 mV (referred to input)
1 mV/°C (referred to input)

Internal DC current source
Gain

Max Output

DC accuracy

Resolution

Drift (typ.)

1 nA/V
10 nA/V
100 nA/V
1 µA/V
10 µA/V
100 µA/V
1 mA/V
10 mA/V
50 mA/V

2 nA
20 nA
200 nA
2 µA
20 µA
200 µA
2 mA
20 mA
100 mA

0.5 % + 10 pA
0.5 % + 10 pA
0.5 % + 100 pA
0.1 % + 1 nA
0.1 % + 10 nA
0.1 % + 100 nA
0.1 % + 1 µA
0.1 % + 10 µA
0.1 % + 50 µA

100 fA
1 pA
10 pA
100 pA
1 nA
10 nA
100 nA
1 µA
10 µA

100 ppm/°C + 100 fA/°C
100 ppm/°C + 200 fA/°C
100 ppm/°C + 2 pA/°C
50 ppm/°C + 20 pA/°C
50 ppm/°C + 200 pA/°C
50 ppm/°C + 2 nA/°C
50 ppm/°C + 20 nA/°C
50 ppm/°C + 200 nA/°C
50 ppm/°C + 1 µA/°C

NoiseGain

Noise density
Input off

Noise density
Input onNoise (rms, input off)
(0.1 Hz to 10 Hz)

Noise (rms, input off)
>10 Hz

1 nA/V
10 nA/V
100 nA/V
1 µA/V
10 µA/V100 µA/V
1 mA/V
10 mA/V
50 mA/V

10 fA/√Hz
20 fA/√Hz
60 fA/√Hz
300 fA/√Hz
3 pA/√Hz
30 pA/√Hz
300 pA/√Hz
3 nA/√Hz
15 nA/√Hz

10 fA/√Hz
20 fA/√Hz
60 fA/√Hz
400 fA/√Hz
4 pA/√Hz
40 pA/√Hz
400 pA/√Hz
4 nA/√Hz
20 nA/√Hz

20 fA
80 fA
400 fA
4 pA
40 pA
400 pA
4 nA
40 nA
200 nA

50 pA
50 pA
300 pA
1 nA
5 nA
40 nA
400 nA
4 µA
20 µA

Stanford Research Systems