Time-to-digital converter provides high precision in 3D scanning

The AS6500 is based on the existing ams TDC-GPX2, and offers resolution up to 10ps on four channels and a sampling rate of up to 1.5Msamples/s.

With high precision and a high sampling rate, light detection and ranging (LIDAR) and optical ranging systems in cars, drones and robots can make extremely detailed and accurate ranging measurements with a wide field of view, enabling them to perform accurate object detection and avoidance. In virtual- and augmented-reality applications, real-time 3D image rendering is supported by high sampling speeds and precision in one-centimetre detail.

The AS6500 TDC is optimised for space, power and cost. Like the TDC-GPX2, it is an integrated four-channel converter IC offering single-measurement resolution of up to 20psrms per channel in normal mode, and 20ns pulse-to-pulse spacing. Operating in dual-channel high-resolution mode, it can achieve a maximum resolution of 10psrms with 5ns pulse-to-pulse spacing.

The AS6500 is housed in a new, smaller 40-lead QFN package with a footprint of just six by six millimetres, making it 56% smaller than the TDC-GPX2. Its highly integrated design, which includes a two to 12.5MHz reference clock input, means that few external components are required alongside the device.

Operating from a 3.3V supply, the AS6500 typically consumes just 60mW in normal operation, and draws 60µA in stand-by mode. It supports CMOS interfaces from a host system, and provides its calibrated output as a digital signal over a standard serial peripheral interface (SPI), for easy data processing in a host controller or processor.

The AS6500 is ideal for optical applications including general-purpose laser distance measurement in 1D, 2D and 3D, speed control, vehicle/truck scanning, object recognition, time-of-flight spectroscopy, automated test equipment (ATE), biomedical technology and analytics.

ams supplies a development kit, the AS6500-QF_DK, which includes a programmer and GUI software for PCs, enabling users to configure and connect their Start and Stop signals and begin taking sample time measurements within minutes.

Norbert Breyer, Product Manager at ams, said: “Increasing numbers of design teams are looking to implement laser ranging or 3D scanning systems in handheld or consumer devices, and limited space on the board is, in many cases, a design constraint. 

“Using the AS6500 enables designers both to achieve very high levels of accuracy and precision, and to restrict the board footprint to a very small size. The AS6500 provides a critical block of an optical sensor system, and is compatible both with today’s AFD-based and with future SPAD-based receiver components.”

The AS6500 is available now in production volume. Unit pricing is available on request from ams.