Steffen Pahlke KETEK VITUS Silicon Drift Detector APPLICATION NOTE KETEK VITUS Silicon Drift Detector (SDD) with new ultra low capacitance FET KETEK introduced the new VITUS SDD with ultra low capacitance FET. This further improves the performance especially at the shorter peaking times and leads to higher throughput and better energy resolution. The new FET is available for all VITUS SDD sizes. The new VITUS SDD generation can be operated under the same operating conditions. They are fully compatible to the previous SDDs. 1. Specifications Parameter Conditions/Comments Min Typ Max Tolerance Unit VOLTAGES FET-Substrate/Bulk -7-4 -2 ±1 V Drain 1 3 4 ±0.1 V CURRENTS Drain 2 3 4 ±0.1 ma Gain 0.9 ±30% mv/kev 2. ESD Caution ESD (Electrostatic Discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality. 3. Absolute Maximum Ratings Parameter Rating VOLTAGES FET-Substrate/Bulk -15V CURRENTS Drain 10mA Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the applications and operations section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Rev. 0 Information furnished by KETEK is believed to be accurate and reliable. However, no responsibility is assumed by KETEK for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of KETEK. Trademarks and registered trademarks are the property of their respective owners. KETEK GmbH, Hofer Str. 3, D-81737 München, Germany Tel: +49-(0)89-67346770 Fax: +49-(0)89-67346777 www.ketek.net 2011 KETEK GmbH. All rights reserved.
4. Typical Performance Characteristics Rev. 0 Page 2 of 5 KETEK GmbH
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5. Difference to previous FET The only difference of the new VITUS SDD generation with the new low capacitance FET compared to the previous version is a slightly higher gain. Due to the lower capacitance the gain is 20 to 30% higher than before. Using the same preamplifier in combination with the new SDD leads to higher slope of the ramped output signal for Reset-type preamplifiers and higher baseline offset for RC- Feedback type preamplifiers at high operating temperatures. Please note that even using a CR network in combination with the Reset-type preamplifier can cause the same behaviour of the baseline. In some cases this might lead to a misinterpretation of the baseline by the signal processing unit following. This effect can be compensated by adjusting the gain of the preamplifier to lower values. Additionally the reset mechanism has to be adjusted due to the different capacitance. Depending in how the reset pulse is triggered it might be necessary to adapt the thresholds for the activation and deactivation of the pulse. Else this might lead to an over- or undershoot of the ramp amplitude limits. This effect can be compensated by using a precision Schmitt-Trigger. Rev. 0 Page 4 of 5 KETEK GmbH
Revision History 12/09 Revision 0: Initial Version Contact KETEK Headquarter Sales Office KETEK GmbH Hofer Str. 3 81737 München Email info@ketek.net Phone +49 (0) 89 673467 70 Fax +49 (0) 89 673467 77 www.ketek.net Rev. 0 Page 5 of 5 KETEK GmbH