MT3825BA: A 384x288-25 mu m ROIC for Uncooled Microbolometer FPAs

Eminoglu S., Gulden M. A., Bayhan N., Incedere O. S., Soyer S. T., Ustundag C. M. B., ...More

40th Conference on Infrared Technology and Applications, Maryland, United States Of America, 4 - 08 May 2014, vol.9070 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 9070
  • Doi Number: 10.1117/12.2057510
  • City: Maryland
  • Country: United States Of America
  • Middle East Technical University Affiliated: Yes


This paper reports the development of a new microbolometer Readout Integrated Circuit (ROIC) called MT3825BA. It has a format of 384 x 288 and a pixel pitch of 25 mu m. MT3825BA is Mikro-Tasarim's second microbolometer ROIC product, which is developed specifically for resistive surface micro-machined microbolometer detector arrays using high-TCR pixel materials, such as VOx and a-Si. MT3825BA has a system-on-chip architecture, where all the timing, biasing, and pixel non-uniformity correction (NUC) operations in the ROIC are applied using on-chip circuitry simplifying the use and system integration of this ROIC. The ROIC is designed to support pixel resistance values ranging from 30 K Omega to 100 K Omega. MT3825BA is operated using conventional row based readout method, where pixels in the array are read out in a row-by-row basis, where the applied bias for each pixel in a given row is updated at the beginning of each line period according to the applied line based NUC data. The NUC data is applied continuously in a row-by-row basis using the serial programming interface, which is also used to program user configurable features of the ROIC, such as readout gain, integration time, and number of analog video outputs. MT3825BA has a total of 4 analog video outputs and 2 analog reference outputs, placed at the top and bottom of the ROIC, which can be programmed to operate in the 1, 2, and 4-output modes, supporting frames rates well above 60 fps at a 3 MHz pixel output rate. The pixels in the array are read out with respect to reference pixels implemented above and below actual array pixels. The bias voltage of the pixels can be programmed over a 1.0 V range to compensate for the changes in the detector resistance values due to the variations coming from the manufacturing process or changes in the operating temperature. The ROIC has an on-chip integrated temperature sensor with a sensitivity of better than 5 mV/K, and the output of the temperature sensor can be read out the output as part of the analog video stream. MT3825BA can be used to build a microbolometer FPAs with an NETD value below 100 mK using a microbolometer detector array fabrication technology with a detector resistance value up to 100 K Omega, a high TCR value (>2 % /K), and a sufficiently low pixel thermal conductance (G(th) <= 20 nW / K). MT3825BA measures 13.0 mm x 13.5 mm and is fabricated on 200 mm CMOS wafers. The microbolometer ROIC wafers are engineered to have flat surface finish to simplify the wafer level detector fabrication and wafer level vacuum packaging (WLVP). The ROIC runs on 3.3 V analog and 1.8 V digital supplies, and dissipates less than 85 mW in the 2-output mode at 30 fps. Mikro-Tasarim provides tested ROIC wafers and offers compact test electronics and software for its ROIC customers to shorten their FPA and camera development cycles.