TDC OVERVIEW
Time-to-digital converters (TDCs) are devices used to measure time intervals in the range of 1 nanosecond down to the picosecond range. The first time-to-digital converters were developed for scientific and research purposes. They were considered a combination of a time-to-analog (TAC) and analog-to-digital (ADC) converter.
The ScioSense (previously acam) Time to Digital Converters are used in applications that were previously analog based. They offer much higher resolution and lower current consumption than their analog counterparts. This low current consumption makes these time to digital converters ideal for wireless applications.
Advantages
- Ultra Low Current Consumption with only few µA.
- Up to 8 STOP Channels
- Automatic Calibration of the Measured Value
- External Reference Clock in the Range of 1 to 40 MHz.
Products
Integrated Digital Time To Digital Converters
Thanks to modern CMOS-technology it is possible to integrate fully digital time to digital converters into a single chip. The high precision of the time measurement – down to 14 ps – in combination with the large dynamic range (up to 30 Bit), the high stability over temperature and supply voltage and the possibility of a low cost production thanks to the CMOS technology make them the first choice for industrial applications.
Additional Information
TDC MEASURING METHOD
INTEGRATED DIGITAL TIME-TO-DIGITAL CONVERTERS
Digital delay time TDCs are integrated circuits for high precision time interval measurement and do this without any analog components. They became real thanks to the innovations in semiconductor technology made over the years. They use the propagation delays of simple logical gates (i.e. inverters) for fine quantization of time intervals. Due to the enormous achievements in signal speed, especially in the CMOS sector, it has become possible to implement
such TDCs in standard CMOS technology with a resolution in the picosecond range. Nowadays we can integrate system solutions into a single chip that are efficient, power saving, space saving and none the less low price.
Digital TDCs can be split into two groups:
- Absolute delay time TDCs
- Relative delay time TDCs
ABSOLUTE DELAY TIME TDC
This type of TDC uses the absolute propagation time of signals through simple logical elements for fine quantisation of time intervals. (see figure below)
In other words, it determines how many inverter cycles the measured time interval consists of. The figure shows the principle of operation. Clever circuit set-ups, redundant elements and special layout methods on the chip enable the exact reconstruction of the number of basic time intervals. The resolution strictly depends upon the basic delay time in the chip. Resolutions in the range of 14 -100 ps can be achieved by a simple set-up of the measuring core and the use of a state-of-the art CMOS process. The propagation delay itself depends on temperature and supply voltage. Therefore the measured value must be calibrated. This is done by measuring one and two periods of a reference oscillator. Ideally this measurement and the following calculation is done by the TDC itself.
Absolute delay time TDCs have the following advantage:
- The delay time of the inverter can be precisely adjusted and stabilized by using a phase controlled loop (PLL). It is independent from supply voltage and temperature.
- Good pulse-pair resolution
- Multi-hit capability

Customer-specific Integrated TDCs
The use of pure digital circuit design makes it easy to build on the performance features of the standard products and improve specific technical data. Accordingly, ScioSense (previously acam) develops optimized TDC’s which are tailored to the specific measuring requirements of the customer.
- Additional measuring modes
- Additional mathematical operations for on-chip data processing (e.g. high performance 32 floating point units with focus on low power consumption)
- Memory (FIFO, EEPROM…)
- Various interfaces
- µC cores
The wealth of experience ScioSense (previously acam) has gathered assures the ability to integrate all necessary functions on a single circuit and so to provide a system-on-chip solution.
Implementation Examples
TDC-S1 is a TDC with 25ps standard deviation for use in the ATV (Automatic Transport Vehicle) that will supply the ISS (International Space Station). The high resolution is all the more impressive as this TDC is realized on a radiation hard process.
DFA1 Integrated circuit for detection of the rotation of a propeller meter with extremely low current consumption (<2uA) – contacless, non-magnetic und feedbackless.
Customer-specific Systems
On the base of the ATMD-System we also develop complete solutions and additional modules to fit your application.
Take as an example the AM-HM1 histogramming module, that was developed for RoentDek. This is a standalone PC-based 4-channel TDC with 32MB Histogram memory for fast readout of Delay-Line-Detectors developed by RoentDek. For more information, please contact RoentDek.
Another example is the Time-of-Flight Module offered by GPTA (Gesellschaft für physikalisch-technische Anwendungen). The key features of this module are virtually dead time free operation, 5 ns multihit dead time in 1 channel mode, (60±5) ps maximum resolution, an input for multicard coincidence measurements. For more information, please email sales@gpta.de
Time-of-flight Module
Documentation & Downloads
Datasheet
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DescriptionDatasheet TDC-GP22 Eval System: |
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Datasheet
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Software
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Ordering Numbers
Type | Part number | Package | RoHS compl. | Shipping package |
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TDC-GP22: | ||||
TDC-GP22 | MNR 1949 | QFN32 | Yes | Tray |
TDC-GP22 | MNR 1950 | QFN32 | Yes | Tape & Reel (5k) |
GP22-EVA-KIT | MNR 1951 | System | Yes | Box |
GP22-DEMO-KIT | MNR 1979 | System | Yes | Box |
TDC-GP21: | ||||
TDC-GP21 | MNR 1839 | QFN32 | Yes | Tray |
TDC-GP21 | MNR 1720 | QFN32 | Yes | Tape & Reel (3K/5K) |
GP21-EVA-KIT | MNR 1781 | System | Yes | Box |
TDC-GP2: | ||||
TDC-GP2 | MNR 1058 | QFN32 | Yes | Tray |
TDC-GP2 | MNR 1480 | QFN32 | Yes | Tape & Reel (2k) |
TDC-GP1: | ||||
TDC-GP1 | MNR 278 | TQFP44 | Yes | Tray |
TDC-GPX: | ||||
TDC-GPX | MNR 975 | TQFP100 | Yes | Tray |
TDC-GPX-FG | MNR 1089 | TFBGA120 | Yes | Tray |
Ordering Numbers
Type | Part number | Package | RoHS compl. | Shipping package |
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TDC-GP22: | ||||
TDC-GP22 | MNR 1949 | QFN32 | Yes | Tray |
TDC-GP22 | MNR 1950 | QFN32 | Yes | Tape & Reel (5k) |
GP22-EVA-KIT | MNR 1951 | System | Yes | Box |
GP22-DEMO-KIT | MNR 1979 | System | Yes | Box |
TDC-GP21: | ||||
TDC-GP21 | MNR 1839 | QFN32 | Yes | Tray |
TDC-GP21 | MNR 1720 | QFN32 | Yes | Tape & Reel (3K/5K) |
GP21-EVA-KIT | MNR 1781 | System | Yes | Box |
TDC-GP2: | ||||
TDC-GP2 | MNR 1058 | QFN32 | Yes | Tray |
TDC-GP2 | MNR 1480 | QFN32 | Yes | Tape & Reel (2k) |
TDC-GP1: | ||||
TDC-GP1 | MNR 278 | TQFP44 | Yes | Tray |
TDC-GPX: | ||||
TDC-GPX | MNR 975 | TQFP100 | Yes | Tray |
TDC-GPX-FG | MNR 1089 | TFBGA120 | Yes | Tray |