Transimpedance devices amplify signals delivered by optoelectronic sensors

Integrated signal amplifiers and converters from MAZeT convert sensor signals from optical sensors in high resolution, and for the frequency and bandwidth required by the specific application. The extended range of signal ASICs comprises the fast MTI04 and MTI08 transimpedance amplifiers and analog converters as well as the MDDC04AQ and MCDC04EQ current-to-digital converters, featuring very high amplification and bandwidth. The ASICs meet the demand in the area of signal electronics for fast real-time signal conversion in inline processes as well as processing, for example, extremely low sensor signal levels that are sometimes only slightly above the inherent noise range, says the company. “Optoelectronic sensors are semiconductor diodes with a power output; in many technical applications, they also function as an individual receiver or as arrays for light detection,” said Frank Krumbein, product manager, colour and spectral sensoring, MAZeT. “The application spectrum ranges from simple light barriers to presence detection and optical fiber receivers for data transfer and imaging equipment, such as scanners or digital cameras, right through to facilitating measuring technology applications including the analysis of states, movements or light-related parameters such as brightness or colours.” All signal ASICs contain four or eight signal channels and can be dynamically programmed in the process by means of multiple amplification levels. This makes them very well suited for multi-channel sensor systems in applications with dynamic amplification and a high sensor bandwidth. All converters feature highly compact dimensions and are also available in space-saving (Q)SOP packages or alternatively as COB technologies. Transimpedance Amplifiers with Analog Output - Transimpedance amplifiers (TIA) used as current-voltage converters ensure continuous signal processing at high signal frequencies, thus meeting the demands of automated processes. They are best suited to synchronous measuring procedures in the kilohertz range, where fast converters are required to scan optical signals. Examples include sensors for quality testing in inline manufacturing processes or those in touchless handheld devices. The MTI04 with analog output can convert up to four photo currents per chip within an 8-pin programmable amplification level featuring parallel signal output. The MTI08 8-channel converter augments the functions of the MTI04 by adding sample & hold as well as a multiplexer at the voltage output. To implement this, MAZeT integrates a TIA with multiple channels into an ASIC and adds extra functions such as programmability, power down, or multiplexer. This results in reduced space requirements as compared with the discrete design, the temperature coefficient of the amplification is lower, and the individual channels provide very good synchronization properties across the gain stages. Multi-Channel Current-to-Digital Converters - The MDDC04 and MCDC04AQ converters with digital outputs also feature high-resolution on-chip AD conversion in addition to signal amplification and temperature compensation and can be programmed using a digital interface. The MDDC04 contains four current-voltage converters that work in cycles, and for each channel 16 transimpedances can be separately adjusted in binary increments. Using the maximum transimpedance, even currents in the nano-ampere range can be measured quickly while covering a dynamic range of 30 dB. The chip is ideally suited to higher signal frequencies in the kilohertz range and is therefore recommended for fast synchronous measuring processes. The MCDC04AQ current-to-digital converter converts photo currents from detectors via a continually integrating load balance procedure and makes them available via an I²C interface as digital data in 16-bit format on the output side. Due to the internal current load conversion in the corresponding parameters, the signal ASIC is ideal for use in connection with optical sensors for applications with very little light or with a high variance in light that require the measurement of light in a broad range from very low to very high levels of light. Other applications include light control with dimming or fluorescence measurements in the area of analysis technology, says the company.