(1/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki PSI tests - Comparator Results Devices under test and beam conditions Schematics Results o Input bias current o Output drift o I-V acquisition of the comparator outputs o Gain o Response time o SET

(2/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Devices under test and beam conditions DUT o LM339D, LP339M and LM139: SET o LM339D and LP339M Input bias measurements o LM339D: Output drift I-V acquisition of the comparator outputs Gain Response time Beam conditions: o PIF facility at PSI Proton energy was set to 230 MeV Dose rate : 7.5 rad/s (270 Gy/h)

(3/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Schematics SET evaluation From literature, the lowest ΔVin gives the highest chance to get SETs

(4/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Schematics Input bias current

(5/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Schematics Output drift / Response time / Gain / I-V measurements 4 kinds of measurements performed: Output drift by applying a constant V(-) during irradiation During test breaks: Gain by applying a saw tooth at V(-) Response time by supplying V(-) with a square wave I-V curves by using a Source Measure Unit (Keithley)

(6/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Input Bias Current 1 st Run Up to 80 Gy Vin > 0 V(-) = 7.5V I(+) = 75 nA → V(+) = 7.5 V At 80 Gy run was stopped Change supply voltage from: +/- 15V to 0/34V LM339D

(7/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Input Bias Current 2 nd Run Vin > 0 V(-) = 17V I(+) = 170 nA → V(+) = 17 V At ≈ 155 Gy → I(+)max is exceeded (250 nA)

(8/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Input Bias Current LP339M At ≈ 57 Gy → I(+)max is exceeded (25 nA)

(9/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Output Drift LM339D Vout init set to –Vcc (-15V) Test break : Other measurements (Gain etc…) Trend of the Vout variation vs dose: Vout tends to lower values From 0 to 300Gy: Vout drifted from: V to V (32 mV) Can be assumed as very small Datasheet affords no information concerning the allowed drift

(10/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki I-V measurements of the comparator outputs LM339D Test break : I-V measurements Source-Measure Unit (Keithley) Inject I and measure Vout

(11/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki I-V measurements of the comparator outputs LM339D A trend of the output is observable: o I-V curves → Lower values of Ic vs Dose Active field of the transistor Breakdown Reasons: o β (output transistor) decreased o Current source is damaged

(12/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Gain Test break : V(-) → Sawtooth waveform ΔV = 10mV V(+) → Ground

(13/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Gain Specifications: Gain min = 50V/mV Gain of the 2 irradiated comparators decrease vs dose Variation of the reference Gain is due to the limited resolution of the scope to measure Vin. The increase of Vin is due to the input offset As dose increases, ΔVin increases to change the output state → Low resolution is less dominant Switching voltage increases with dose.

(14/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Response time A step from -100mV to +100mV was applied on V(-). Results show that response time increases vs dose with respect to the reference: Rising time can be acceptable depending on the application o 50% after a TID of 150 Gy (from 2.1 µs to 3 µs) o 220% after a TID of 300Gy (from 2.1 µs to 4.75 µs)

(15/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Summary of the Results Test typeComparator typeLimit TID (Gy)Corresponding Fluence (p + 230MeV/cm 2 ) Comments/observations Input bias current LM339D1552.9×10 11 Input bias current increases vs TID. LP339M is the more sensitive LP339M561.04×10 11 Gain LM339D ×10 11 Gain decreases vs TID The gain value can be accepted depending on the application I-V curves LM339DNo indication in the Datasheet I-V curves drift to lower values of I as TID increases. β of the output transistor and/or a current source inside the comparator is affected by radiation. Output drift LM339DNo indication in the Datasheet From 0 to 300 Gy Vout drifts by 32mV toward lower values Response time LM339DNo indication in the Datasheet Tr increases vs TID The Tr value can be accepted depending on the application The analysed parameters show a degradation. In some cases the datasheet limit is exceeded

(16/16) 08/05/12 – RadWG meeting G. Spiezia, P. Peronnard, E. Lefteris, P. Oser, J. Mekki Conclusions No SET (>15 ns and > 100 mV) have been observed for any of the DUTs. The analysed parameters show a degradation In some cases the datasheet limit is exceeded as shown in the previous table The degradation can be tolerated depending on the application