• Flexible setup
  • Easy to use
  • Compact

The transimpedance amplifier TZA500 is designed for precise measurement of current, from pA to mA. The output is a voltage linearly proportional to the input current.

The TZA500 is very flexible with USB and hard-wire interface control of gain, bandwidth and polarity. A graphical user interface is delivered with the amplifier.

  • Interfaces: USB and hard-wire (DB25)
  • Rise time: 45µs
  • Noise equivalent current: 30 p(ARMS)
  • Gain, bandwidth and polarity control: 6 gain ranges; 4 bandwidths; polarity inversion
  • Auto-null function: up to 10V offset nulling

PRINCIPLES OF OPERATION

The TZA500 measures small currents e.g. optical power via a photodiode. Photodiodes are useful for power measurement in the visible and near infra-red due to their inherent sensitivity and speed of measurement.

Photodiodes produce a current which is proportional to the incident light power over a wide dynamic range.

The current is converted to a voltage through a precise transimpedance amplifier. This amplifier is very linear over the full measurement range of the device. The TZA500 has 6 gain ranges. The switch is a semiconductor device, free from degradation.

A unique feature of the TZA500 is the auto-null function. Further functions include signal inversion and bandwidth reduction. The analogue output signal is available at the BNC connector on the front panel an on the appropriate line on the interface port on the back panel.

The voltage generated is then converted to a digital value via a 12 bit A/D converter. This process and all calculations and communication with the PC are controlled by a microcontroller. The measurement process is started via a command over the USB interface (software trigger). Alternatively, a continuous measurement stream can be started which samples at 1.5 kS/s.

The measured photocurrent may then be read out from the USB port.

Transimpedance Amplifier TZA500 1

FIELDS OF APPLICATION

These transimpedance amplifiers are particularly useful for the measurement of current from photodiodes. The output is a voltage linearly proportional to input current and thus, to input power in photodiode monitoring applications.

The fast response time at high signal-noise ratio makes this TZA series particularly useful in systems control feedback loops.

The high sensitivity and large dynamic range allow measurement of a wide range of optical sources such as lasers and LEDs via a variety of photodiodes for these applications such as Si and InGaAs.

The TZA500 series is insensitive to electromagnetic interference by design, an important factor when working in „dirty“ industrial environments. The proprietary auto-nulling function allows up to 10V of offset nulling. This is particularly useful for nulling dark current or for eliminating a DC signal component to concentrate on signal changes, such as in component burn-in and life-time testing.

ParameterConditionsMinTypMaxUnits
Input
Current ranges (full scale)10
1
100
10
1
100
mA
mA
µA
µA
µA
nA
Noise equivalent current (NEIRMS), range:10mA
1mA
100µA
10µA
1µA
100nA
300
30
3
300
30
3
nA
nA
nA
pA
pA
pA
Impedance0 (virtual short circuit)Ω
ConnectorsBNC and BR2 (Adapters for other connector systems available)
Output
FunctionLinear analogue : Vout = scale factor x Iin
Output scale, range:10mA
1mA
100µA
10µA
1µA
100nA
1
10
0.1
1
10
0.1
V/mA
V/mA
V/µA
V/µA
V/µA
V/nA
ConnectorsBR2 and DB25 (Adapters for other connector systems available)
Output range (full scale)10V
Rise / Fall time (10% – 90%)Small Signal (-1 → +1V)
Large Signal (-10 → +10V)
45
65
µs
Setting time (1%)Small Signal (-1 → +1V)
Large Signal (-10→ +10V)
100
140
µs
Accuracy± 1%
Linearity± 0.1± 0.2dB
Output impedance50Ω
Logic
Current required for switching (5V)-100.0110µA
Switching time150 (Logical switching <1µs; effective switching time is limited by setting time)µs
Power supply
TypeWall plug (supplied)
Dimensions30 x 50 x 60mm
Dimensions
1 channel105 x 45 x 116 (w x h x l);
w=130mm incl. case wings
mm
2 channels105 x 66 x 116 (w x h x l);
w=130mm incl. case wings
mm
4 channels105 x 106 x 116 (w x h x h);
w=130mm incl. case wings
mm
> 4 channels19“ rack, 3U
  • Input configuration: single ended, differential
  • Input receptacle: BNC, BR2
  • Bias: none, receptacle for external bias input
  • Case: gull wing, lab style
  • BR2 connector,
  • BR2 receptacle,
  • bias input connector
Transimpedance Amplifier TZA500 2

Artifex Software Development Kit

The SDK is a fixed, free component when purchasing a device.

It comes with the source code of the application program (in VB.net) and a LabView VI with the basic functions of the instrument. A description of the communication with the devices and a list of the commands used is also included.

For some devices (currently LDD100, LIV120 in preparation) there is a dll file (library file) with documentation and exemplary applications in VB.net and LabView.

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