The AMP100 transimpedance amplifier—a compact, versatile device designed to handle low-frequency applications with exceptional accuracy. Manufactured by Thorlabs, a leader in optical and electronic components, the AMP100 stands out for its switchable gains, low noise, and user-friendly design. This informational blog dives deep into everything you need to know about the AMP100 transimpedance amplifier, from its core features to real-world applications. By the end, you’ll understand why it’s a go-to choice for engineers and researchers alike.
As of 2025, with advancements in photonics pushing boundaries in fields like AI-driven optical networks and portable diagnostics, tools like the AMP100 remain essential for bridging the gap between sensitive sensors and data acquisition systems. Let’s explore this powerhouse in detail.
Table of Contents
What is a Transimpedance Amplifier?
Before we zoom in on the AMP100 transimpedance amplifier, it’s crucial to grasp the basics. A transimpedance amplifier (TIA) is an electronic circuit that converts current to voltage. It’s commonly used with photodiodes, where light generates a small current (often in the picoampere to microampere range) that needs amplification for further processing.
Unlike voltage amplifiers, TIAs employ a feedback resistor to set the gain, measured in volts per ampere (V/A). This design maintains a virtual ground at the input, minimizing voltage swings and ensuring high bandwidth and low noise—key for sensitive measurements. TIAs are vital in applications requiring fast response times and high precision, such as fiber-optic communications, laser ranging, and fluorescence detection.
The AMP100 transimpedance amplifier exemplifies this technology at a low-frequency scale, prioritizing accuracy over speed. It’s ideal for scenarios where bandwidth isn’t the primary concern, but signal integrity is. According to industry sources, TIAs like the AMP100 help mitigate issues like dark current in photodiodes, ensuring cleaner outputs.<grok:render type=”render_inline_citation”>
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Key Features of the AMP100 Transimpedance Amplifier
The AMP100 transimpedance amplifier packs a punch in a small package, making it suitable for lab benches, portable setups, and integrated systems. Here are its standout features:
- Switchable Gain Settings: Choose from 1 MV/A, 10 MV/A, or 100 MV/A (that’s 10^6, 10^7, or 10^8 V/A). This flexibility allows adaptation to various input current levels without swapping components.
- Polarity Switch: Easily toggle between anode-grounded (AG) or cathode-grounded (CG) configurations to match your photodiode’s setup.
- Zero Adjustment: A dedicated screw eliminates offsets from dark currents, ensuring baseline accuracy. Readjust after gain changes for optimal performance.
- Low Input Noise: At 0.06 pA/√Hz (DC to 1 kHz), it minimizes interference, crucial for high-precision tasks.
- Compact In-Line Design: With BNC connectors on both ends, it integrates seamlessly between cables, powered via a Micro-B USB port with an included 5V/2A supply.
- LED Power Indicator: A simple visual cue confirms operation, preventing setup errors.
- Robust Build: Weighing just 0.53 lbs, it’s durable yet lightweight, with a two-year warranty from Thorlabs.
These features make the AMP100 not just functional but intuitive, reducing setup time and errors in demanding environments.<grok:render type=”render_inline_citation”>
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Detailed Specifications of the AMP100
To appreciate the AMP100 transimpedance amplifier fully, let’s break down its specs in a clear table. These parameters highlight its low-frequency focus, with a bandwidth up to 1 kHz—perfect for steady-state measurements rather than high-speed pulses.
| Specification | Details |
| Transimpedance Gain | Switchable: 1 MV/A, 10 MV/A, 100 MV/A |
| Bandwidth (3 dB) | DC to 1 kHz (typical, with ≤10 nF source capacitance) |
| Input Current Limits | ±2 μA (1 MV/A), ±200 nA (10 MV/A), ±20 nA (100 MV/A) |
| Input Impedance | 100 Ω |
| Input Current Noise | 0.06 pA/√Hz (DC to 1 kHz, typical) |
| Output Voltage Range | -1.0 V to +1.0 V (50 Ω load); -2.0 V to +2.0 V (high-Z load) |
| Output Impedance | 50 Ω |
| Rise/Fall Time | <300 μs (10% to 90%) |
| Power Supply | 5 V DC, 2 A (via Micro-B USB); Quiescent current: 45 mA |
| Dimensions | Compact in-line box (exact: refer to Thorlabs drawings) |
| Operating Environment | Non-explosive; avoid EMI from nearby devices like cell phones |
Note: Performance varies with source capacitance—use short cables for best results. Exceeding input limits risks saturation or damage.<grok:render type=”render_inline_citation”>
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Priced around $575 as of recent listings, it’s a cost-effective option for its capabilities.<grok:render type=”render_inline_citation”>
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Applications of the AMP100 Transimpedance Amplifier
The AMP100 transimpedance amplifier shines in low-frequency, high-precision scenarios. Its design caters to photodiodes and similar sensors, making it versatile across industries. Here are key applications:
- Optical Sensing and Detection: Amplify signals from photodiodes in fluorescence microscopy or environmental monitoring. For instance, it’s used in IR-based portable blood alcohol detection systems, where precise current conversion ensures accurate readings.<grok:render type=”render_inline_citation”>
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- Biomedical Instrumentation: In devices like flow cytometers or biosensors, the AMP100 handles tiny currents from light-sensitive elements, aiding in diagnostics and research.
- Scientific Research: Recent studies, including those on optical neural networks, employ the AMP100 for amplifying photocurrents in forward-mode training setups. A 2024 Nature paper highlighted its role in capturing signals with 100 kΩ transimpedance.<grok:render type=”render_inline_citation”>
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It’s also featured in noisy luminous environment studies for untangling light signals.<grok:render type=”render_inline_citation”>
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- A/D Converter Pre-Amplification: Boost weak signals before digitization, ensuring compatibility with oscilloscopes or data loggers.
- Educational and Prototyping: Ideal for labs teaching electronics, due to its ease of use and adjustable parameters.
- Custom Integrations: In LIDAR prototypes or space-based photon counting, though its 1 kHz bandwidth limits it to non-high-speed uses.
In 2025, with the rise of 6G wireless and NDI (non-destructive inspection), similar amplifiers are evolving, but the AMP100’s reliability keeps it relevant for foundational work.<grok:render type=”render_inline_citation”>
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How to Use the AMP100 Transimpedance Amplifier
Setting up the AMP100 transimpedance amplifier is straightforward, but attention to detail ensures peak performance. Follow these steps:
- Connect the Hardware: Attach your photodiode or current source to the INPUT BNC (female). Link the OUTPUT BNC to your measurement device (e.g., oscilloscope).
- Power It Up: Plug the included 5V/2A supply into the Micro-B USB on the INPUT side. The LED should light up.
- Select Polarity: Use the switch on the OUTPUT end—AG for anode-grounded photodiodes, CG for cathode-grounded.
- Set Gain: Choose 1, 10, or 100 MV/A based on expected current. Start low to avoid saturation.
- Adjust Zero: With no input signal, turn the ZERO ADJ. screw until the output is zero. Recheck after gain changes.
- Optimize Setup: Use shielded, short cables to reduce capacitance and noise. Avoid EMI sources.
- Test and Monitor: Apply a known current and verify output voltage. Monitor for saturation.
Safety tip: Never open the unit—servicing requires qualified personnel. For integration tips, Thorlabs provides CAD files and schematics.<grok:render type=”render_inline_citation”>
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Advantages and Limitations
The AMP100 transimpedance amplifier offers clear advantages: affordability, ease of use, and low noise for precision work. Its switchable features reduce the need for multiple devices, saving costs and space.
However, limitations include its 1 kHz bandwidth, unsuitable for high-speed applications like Gbps fiber optics (where Marvell’s TIAs excel).<grok:render type=”render_inline_citation”>
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It’s also sensitive to source capacitance, requiring careful cabling.
Comparisons with Other Transimpedance Amplifiers
Compared to the Koheron AMP100 (a voltage amplifier, not TIA), Thorlabs’ model is purpose-built for current conversion.<grok:render type=”render_inline_citation”>
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Versus higher-end options like Analog Devices’ ADA4530, the AMP100 is more affordable but lower bandwidth.<grok:render type=”render_inline_citation”>
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For ultra-high precision, it outperforms basic DIY circuits in noise performance.
In the market, it’s competitively priced against similar 1 kHz TIAs, with superior warranty support.
Unique FAQ Section on the AMP100 Transimpedance Amplifier
Here’s a curated FAQ addressing common queries, based on user forums and specs:
What makes the AMP100 suitable for photodiode applications?
Its high gain options and zero adjustment handle dark currents effectively, ensuring accurate light-to-current conversions in low-light setups.
Can the AMP100 handle high-speed signals?
No—its 1 kHz bandwidth suits DC to low-frequency tasks. For faster needs, consider amplifiers with 100 MHz+ bandwidth.
How do I prevent noise in my AMP100 setup?
Use short, shielded cables, keep away from EMI sources, and maintain low source capacitance (≤10 nF).
Is the AMP100 compatible with all photodiodes?
Yes, via the polarity switch (AG/CG). Ensure input currents stay within limits to avoid damage.
What’s the difference between transimpedance and voltage amplifiers?
TIAs like the AMP100 convert current to voltage with feedback, ideal for sensors; voltage amps boost voltage signals directly.
Where can I buy the AMP100 and what’s the warranty?
Available from Thorlabs or resellers like MEETOPTICS. It comes with a two-year warranty.<grok:render type=”render_inline_citation”>
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How does the AMP100 compare to custom TIA circuits?
It’s plug-and-play, saving design time, though custom builds can offer tailored bandwidth.
Conclusion
The AMP100 transimpedance amplifier stands as a cornerstone for engineers and researchers tackling low-frequency, high-precision current-to-voltage conversion tasks. With its robust feature set—switchable gains, low noise, and intuitive design—it empowers applications from optical sensing to biomedical research, all while maintaining affordability and ease of use.
While its 1 kHz bandwidth limits it to non-high-speed uses, its reliability, backed by Thorlabs’ two-year warranty, ensures it remains a trusted tool in labs and prototypes worldwide. Whether you’re a seasoned professional or a curious student, the AMP100 offers a seamless way to amplify tiny signals with confidence.
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