Design and realization of a 144x7 silicon readout integrated circuit (ROIC) based on switched capacitor TDI for
MCT LWIR scanning type focal plane arrays (FPAs) and its corresponding hybrid integrated test circuits are
presented. TDI operation with 7 detectors improves the SNR of the system by a factor of √7, while oversampling
rate of 3 improves the spatial resolution of the system. ROIC supports bidirectional scan, 5 adjustable gain
settings, bypass operation, automatic gain adjustment in case of mulfunctioning pixels and pixel select/deselect
properties. Integration time of the system can be determined by the help of an external clock. Programming of
ROIC can be done in parallel or serial mode according to the needs of the system. All properties except pixel
select/deselect property can be performed in parallel mode, while pixel select/deselect property can be performed
only in serial mode. ROIC can handle up to 3.75V dynamic range with a load of 25pF and output settling time of
80ns. Input referred noise of the ROIC is less than 750 rms electrons, while the power consumption is less than
100mW. To test ROIC in absence of detector array, a process and temperature compensated current reference
array, which supplies uniform input current in range of 1-50nA to ROIC, is designed and measured both in room
and cryogenic (77ºK) temperatures. Standard deviations of current reference arrays are measured 3.26% for 1nA
and 0.99% for 50nA. ROIC and current reference array are fabricated seperately, and then flip-chip bonded for the
test of the system. Flip-chip bonded system including ROIC and current reference test array is successfully
measured both in room and cryogenic temperatures, and measurement results are presented. The manufacturing
technology is 0.35μm, double poly-Si, four metal, 5V CMOS process.
Design and measurement of a silicon readout integrated circuit (ROIC) based on switched capacitor time delay
integration (TDI) technique for LWIR HgCdTe Focal Plane is presented. ROIC incorporates time delay integration (TDI)
functionality for scanning type of detector by using switched capacitor technique with a supersampling rate of
three, increasing SNR and the spatial resolution. ROIC, in terms of functionality, is capable of bidirectional scan,
programmable integration time, 5 gain settings at the input and auto gain adjustment with pixel deselection capability.
Programming can be done parallel or serially with test mode functionality. ROIC can handle up to 3.75V dynamic range
with the load being 25pF capacitive, output settling time is less than 80 nsec. This low power ROIC consumes less than
100mW. Moreover, input referred noise is less than 750 rms electrons. Simulations and measurements are done in both
room temperature and cryogenic (77 °K) temperatures. In order to measure and simulate chip without a detector, process
and temperature invariant current source block that imitate detector currents are designed as well. The manufacturing
technology is 0.35μm, double poly-Si, four-metal (3 metals and 1 top metal) 5V CMOS process.
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