The Flexible One!
- Fast
- Wide dynamic range
- Compact
The transimpedance amplifier TZA400 is designed for precise measurement of current, from pA to mA. The output is a voltage linearly proportional to the input current.
The gain of the TZA400 is controlled via a hard-wire interface on the back panel.
- Interface: Hard-wire (DB25)
- Rise time: 1µs (G≤5×105); 4µs (higher gains)
- Bandwidth (-3dB): 350kHz
- Noise equivalent current: 500 p(ARMS)
- Gain control: 16 gain ranges in 1-2-5 pattern or 4 gain ranges in decade spacing
PRINCIPLES OF OPERATION
The TZA400 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 TZA400 has optionally 4 or 16 gain ranges. The switch is a semiconductor device, free from degradation.
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.
FIELDS OF APPLICATION
Photodiode Current and Optical Power Measurement
The TZA400 is particularly suited to measuring current from photodiodes. Because the output voltage is linear with input current, it is also linear with incident optical power, which makes the TZA400 a reliable building block for photodiode monitoring.
Control Feedback Loops
Fast response combined with a high signal-to-noise ratio makes the TZA400 series an excellent choice for closed-loop control systems, such as laser power stabilization.
Polarization Extinction Ratio (PER) Measurement
With 16 gain ranges covering five decades of gain and a gain-to-gain accuracy below 1%, the TZA400 lets you record power curves confidently across its full 6½-decade measurement range. Even demanding tasks like accurate, high-speed, real-time determination of polarization extinction ratio become straightforward.
Industrial Environments
The TZA400 is insensitive to electromagnetic interference by design. This matters in “dirty” industrial environments with motors, drives, and switching power supplies. A modular 19″ rack system makes multi-channel installation simple.
Why Choose the TZA400?
The TZA400 combines speed, range, and robustness in one compact unit. Semiconductor gain switching eliminates wear, the DB25 hard-wire interface enables fast automated range control, and the EMI-resistant design keeps measurements clean in real-world conditions. If you need flexible bias options, the TZA200 and TZA500 complement the TZA400 within the Artifex transimpedance amplifier family.
| wdt_ID | wdt_created_by | wdt_created_at | wdt_last_edited_by | wdt_last_edited_at | Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|---|---|---|---|---|
| 27 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Input | |||||
| 28 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Current ranges (full scale) | Maximum range | 3.7 | mA | ||
| 29 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Minimum range | 37 | nA | |||
| 30 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Noise equivalent current (NEPRMS) | Range: 3.7mA | 2.5 |
µA | ||
| 31 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Range: 37nA | 500 |
pA | |||
| 32 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Connectors | BNC (Adapters for other connector systems available) | ||||
| 33 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Output | 0 | 3.7 | V | ||
| 34 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Function | Linear analogue : Vout = scale factor x Iin | ||||
| 35 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Connectors | BNC (Adapters for other connector systems available) und DB25 | ||||
| 36 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Output scale with 16 range option, range: | 3.7mA 1.85mA 740µA 370µA 185µA 74µA 37µA 18.5µA 7.4µA 3.7µA 1.85µA 740nA 370nA 185nA 74nA 37nA |
1 2 5 0.01 0.02 0.05 0.1 0.2 0.5 1 2 5 0.01 0.02 0.05 0.1 |
V / mA V / mA V / mA V / µA V / µA V / µA V / µA V / µA V / µA V / µA V / µA V / µA V / nA V / nA V / nA V / nA |
||
| 37 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Output scale with 4 range option, range: | 3.7mA 370µA 37µA 3.7µA |
1 0.01 0.1 1 |
V / mA V / µA V / µA V / µA |
||
| 38 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Output range (full scale) | 10 | V | |||
| 39 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Rise / Fall time (10% - 90%) | Source capacitance < 100pF | 1 | µs | ||
| 40 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Bandwidth (-3dB) | 350 | kHz | |||
| 41 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Setting time (1%) | Source capacitance < 100pF | 2 | µs | ||
| 42 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Accuracy | ± 1 | % | |||
| 43 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Output impedance | 50 | Ω | |||
| 44 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Logic | |||||
| 45 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Current required for switching | HI = 5V LO = 0V |
-100 | 5 0 |
100 | nA |
| 46 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Dead time during change of range | 2 (Limited by setting time. The logical switch is complete within 20ns.) | µs | |||
| 47 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Power supply | |||||
| 48 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Type | Wall plug (supplied) | ||||
| 49 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | Dimensions | |||||
| 50 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | 1 channel | 103 x 45 x 116 (w x h x l) | mm | |||
| 51 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | 4 channels | 103 x 106 x 116 (w x h x l) | mm | |||
| 52 | benjamin | 28/04/2026 10:20 AM | benjamin | 28/04/2026 10:20 AM | 19"- rack modules | 3U |
- Number of gains: 4, 16
- Case: gull wing, 19″ rack module
- Number of channels: 1, 2, 3, 4
Application Notes
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Do you need further information? Find useful links here!
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.
FAQs
What is a transimpedance amplifier (TIA)?
A transimpedance amplifier converts an input current, such as a photodiode current, into a proportional output voltage that can be measured with standard instruments. The TZA400 performs this conversion with ±1% accuracy from 37 nA to 3.7 mA full scale.
What detectors are compatible with the TZA400?
The TZA400 works with photodiodes, avalanche photodiodes (APDs), and other current-output sensors.
What bandwidth does the TZA400 support?
The TZA400 offers a bandwidth of 350 kHz (-3 dB). Across its amplifier range, Artifex offers models with bandwidths from kHz to MHz.
What gain levels does the TZA400 offer?
The TZA400 covers transimpedance gains from 10³ V/A to 10⁸ V/A, with either 16 ranges in a 1-2-5 pattern or 4 ranges in decade spacing.
How fast is the TZA400?
The TZA400 has a rise time of 1 µs for gains up to 5×10⁵ V/A and 4 µs at higher gains, with a 1% settling time of 2 µs.
How is the gain of the TZA400 controlled?
Gain is set via a hard-wire DB25 interface on the back panel using 5 V / 0 V logic levels. The semiconductor switch changes range within 20 ns, with a total dead time of 2 µs limited by settling.
How do I connect a photodiode to the TZA400?
Connect the photodiode to the BNC input connector, typically via coaxial cable or a dedicated detector input. Adapters for other connector systems are available.
Does the TZA400 provide bias voltage for photodiodes?
The TZA400 must be configured at the time of order with either zero bias or a fixed bias voltage. For flexible, adjustable bias options, see the TZA200 or TZA500.
Can the TZA400 be used with oscilloscopes?
Yes. The TZA400 voltage output can be connected directly to oscilloscopes or data acquisition systems via the front-panel BNC connector or the DB25 port.
Is the TZA400 suitable for industrial environments?
Yes. The TZA400 is designed to be insensitive to electromagnetic interference and is available in a modular 19″ rack system for industrial installations.
