Our partner Anmesys

Voltage controlled current source

AMS 220 from Anmesys

The AMS220 is a voltage controlled current source with active common mode rejection mode. Common mode voltage signals can result in a large error when using a standard measurement set-up for low resistance measurements or when the contact resistances have a large variation. The AMS220 is designed to overcome this unwanted behavior. It is a unique instrument and uses a patented technique.

  • Optimized for use with lock-in amplifier
  • AC and DC electric measurements
  • Low noise due to being completely analog
  • Replacement of AC resistance bridges in a set-up with lock-in amplifier
  • Can be used with preamplifier AMS540 and AMS560


Voltage-to-current conversion ranges 0.001, 0.01, 0.1, 1 and 10 [mA/V]
Control voltage (VREF) input range (ac/dc) 0 ÷ 3.6 V (rms) / -5 V ÷ +5 V (dc)
Input resistance of the control voltage input 100 kΩ
Maximum output current ac/dc 36 mA (rms) / ±50 mA (dc)
Accuracy of the voltage-to-current conversion (DC) 0.08 %
Temperature drift 50 ppm/°C
Operating modes ACTIVE CMR / ENABLED
(active common mode voltage rejection is activated)

(current output IB is grounded) 
Targeted frequency range for ACTIVE CMR / DISABLED 
operation mode
DC - 20 kHz (DC - 2 kHz for 1 μA/V range) 
Targeted frequency range for ACTIVE CMR / ENABLED
operation mode
DC-200 Hz
Operating voltage swing on the current output IA
against the reference ground (typ.)
up to ±[6.5 V - |VREF/2|] (± 0.3 V)
Operating voltage swing on the current output IB
against the reference ground (typ.)
up to ±6.6 V (± 0.3 V)
Operating range of voltage differences
on the current outputs IA, IB (typ.)
up to ±13.4 V
Maximum voltage at the current outputs
(against the reference ground)
±10 V
Maximum voltage difference on the current outputs ±20 V
Power supply 12 V (ac) / 50-60 Hz
Maximum power input  7 W
Dimensions (W x H x L) 158 mm x 120 mm x 230 mm
Weight 2.3 kg


Measurements of superconductive samples
Measurements of metals at very low temperatures
I-V curves
Hall effect


AMS220 Voltage controlled current source
Elemination of common mode errors - AppNote


Dr. Marc Kunzmann
Dr. Marc Kunzmann


Quantum Design GmbH

Im Tiefen See 58
64293 Darmstadt

Phone:+49 6151 8806-0
Fax:+49 6151 8806920
Dr. Marc KunzmannProduct Manager - Cryogenics & Materials science
+49 6151 8806-46
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