Setup
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Setup Irradiation • Gamma-dose radiation • Low dose rate experiment: 1.2kGy/h exposure time: 130h • High dose rate experiment: 30kGy/h exposure time: 165h On-line test Abstract Radiation assessment Details of the design A 5MGy γ-dose tolerant ΔΣ Time-to-Digital Converter with 5.6ps resolution for LIDAR application Ying Cao ( [email protected] ) , Paul Leroux ( [email protected] ), Wouter De Cock ([email protected] ), Michiel Steyaert ([email protected] ) Conclusion A radiation tolerant third-order ΔΣ TDC is implemented in 0.13μm CMOS. It consumes only 1.7mW power and achieves an ENOB of 11b. Even after an extremely high radiation dose of 3.4MGy, the ENOB drops only 1 bit and, for an OSR of 250, a 10.5ps time resolution is still achieved. 0.13µm CMOS 0.41x0.27mm 2 cor e t i n ti n2 ti n3 e 1 e 2 Captured time signals for each stage Image source: SCK∙CEN - 3dBFS 18kHz -40dBFS 22kH z OSR=25 OSR=250 After 100kHz LPF After 100kHz LPF SNDR: 60.3dB SNDR: 28dB Time-to-Digital converters (TDCs) are highly demanded in digital PLLs, ADCs, and time-of-flight measurement units, which are widely used for nuclear instrumentation. Demonstrating applications can be found in the ATLAS detector at the Large Hadron Collider (LHC), or in an accelerator driven system like MYRRHA (as shown in the left picture): in the spallation target the position of the liquid lead-bismuth free surface has to be monitored by a light detection and ranging system (LIDAR), which consists of two receiver frontend channels and a TDC. This work presents a radiation tolerant multi-stage delta-sigma TDC. It adopts the noise-shaping technique, and achieves a time resolution of 5.6ps, when the oversampling ratio (OSR) is 250. A radiation assessment up to 5MGy proves its robustness. Distance =C · Time/2 Pre- rad Post- rad 1mm distance resolution requires a time resolution of 6.7ps. Die photo and time signals of the TDC Output spectrum and waveform Architecture of the MASH TDC Structure of the LIDAR The 1-1-1 MASH ΔΣ TDC has three stages. Each stage works as a relaxation oscillator, but controlled by the input time signal. The time can be measured by counting the periods of the oscillation clock during the time signal’s active phase. By preserving the phase of the oscillation clock between measurements, first-order noise- shaping is obtained. Third-order noise-shaping can be achieved by cascading all three stages. The frequency of the oscillation clock can be expressed as 1/(2·RC), which is depending only on passive components. Thus, the TDC exhibits inherent PVT tolerance. Additionally, other hardened-by-design techniques have also been implemented to improve the system’s radiation tolerance, such as constant-gm biasing circuit, guard ring, etc. …
description
A 5MGy γ -dose tolerant ΔΣ Time-to-Digital Converter with 5.6ps resolution for LIDAR application. tin. tin2. Ying Cao ( [email protected] ) , Paul Leroux ( [email protected] ), Wouter De Cock ( [email protected] ), Michiel Steyaert ( [email protected] ). tin3. - PowerPoint PPT Presentation
Transcript of Setup
SetupIrradiation•Gamma-dose radiation•Low dose rate
experiment: 1.2kGy/hexposure time: 130h
•High dose rate experiment: 30kGy/hexposure time: 165h
On-line test
Abstract
Radiation assessment
Details of the design
A 5MGy γ-dose tolerant ΔΣ Time-to-Digital Converter with 5.6ps
resolution for LIDAR applicationYing Cao ( [email protected]) , Paul Leroux ([email protected]), Wouter De Cock
([email protected]), Michiel Steyaert ([email protected])
Conclusion A radiation tolerant third-order ΔΣ TDC is implemented in 0.13μm CMOS. It consumes only 1.7mW power and achieves an ENOB of 11b. Even after an extremely high radiation dose of 3.4MGy, the ENOB drops only 1 bit and, for an OSR of 250, a 10.5ps time resolution is still achieved.
0.13µm CMOS0.41x0.27mm2
core
tin
tin2
tin3
e1 e2
Captured time signals for each stage
Image source: SCK CEN∙
-3dBFS18kHz
-40dBFS22kHz
OSR=25
OSR=250After 100kHz LPF
After 100kHz LPF
SNDR:60.3dB
SNDR:28dB
Time-to-Digital converters (TDCs) are highly demanded in digital PLLs, ADCs, and time-of-flight measurement units, which are widely used for nuclear instrumentation. Demonstrating applications can be found in the ATLAS detector at the Large Hadron Collider (LHC), or in an accelerator driven system like MYRRHA (as shown in the left picture): in the spallation target the position of the liquid lead-bismuth free surface has to be monitored by a light detection and ranging system (LIDAR), which consists of two receiver frontend channels and a TDC. This work presents a radiation tolerant multi-stage delta-sigma TDC. It adopts the noise-shaping technique, and achieves a time resolution of 5.6ps, when the oversampling ratio (OSR) is 250. A radiation assessment up to 5MGy proves its robustness.
Distance=C · Time/2
Pre-rad Post-rad
1mm distance resolution requires a time resolution of 6.7ps.
Die photo and time signals of the TDC
Output spectrum and waveform
Architecture of the MASH TDC
Structure of the LIDAR
The 1-1-1 MASH ΔΣ TDC has three stages. Each stage works as a relaxation oscillator, but controlled by the input time signal. The time can be measured by counting the periods of the oscillation clock during the time signal’s active phase. By preserving the phase of the oscillation clock between measurements, first-order noise-shaping is obtained. Third-order noise-shaping can be achieved by cascading all three stages.
The frequency of the oscillation clock can be expressed as 1/(2·RC), which is depending only on passive components. Thus, the TDC exhibits inherent PVT tolerance. Additionally, other hardened-by-design techniques have also been implemented to improve the system’s radiation tolerance, such as constant-gm biasing circuit, guard ring, etc. …
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