ams OSRAM TMF882x Configurable Multi-Zone Time-of-Flight Sensor
The ams OSRAM TMF882x (TMF8820/21/28) is a dToF (direct time of flight) wide field of view optical distance sensor with 940nm integrated IR VCSEL in a 2.0mm x 4.6mm x 1.4mm module achieving up to 5000 mm target detection distance and has up to 3x3, 4x4, 3x6 or 8x8 zones.
The ams OSRAM TMF882x (TMF8820, TMF8821 & TMF8828) are a family of direct time-of-flight (dToF) sensors available in a small footprint modular package with integrated Vertical Cavity Surface Emitting Laser (VCSEL). The dToF device is based on SPAD, TDC and histogram technology and achieves 5000 mm detection range. Due to its lens on the SPAD, it supports 3x3, 4x4, 3x6 and 8x8 multizone output data and a very wide, dynamically adjustable, field of view. A multi-lens-array (MLA) inside the package above the VCSEL widens up the FoI (field of illumination). All processing of the raw data is performed on-chip and the TMF8820/21/28 provides distance information together with confidence values on its I2C interface.
TMF8820 3x3 zones operation
TMF8821 3x3, 4x4 and 3x6 zones operation
TMF8828 3x3, 4x4, 3x6, and 8x8 zones operation
Information only pertains to TMF8828
The ams OSRAM TMF8828 requires unique firmware (different from TMF8820/21/28) that will only operate on the TMF8828. The TMF8828 has two operating modes. It can operate as a TMF8820/21/28 (3x3, 4x4, or 3x6 zones) or in the TMF8828 mode which has 8x8 zones. In the TMF8828 mode, the device implements the 8x8 zone functionality as a sequence of four time-multiplexed measurements of 4x4 zones (like TMF8821). As such, the factory calibration sequence, loading the calibration data, reading the result measurements, and the optional histogram readouts must be performed four times in sequence by the host (please see the Host Driver Communication manual for details). The maximum measurement cycle rate in the TMF8828 mode is 15 Hz with 125 k iterations. Slower cycle rates with an increased number of iterations are possible.
|TMF8828: Multizone with 3x3, 4x4, 3x6 and 8x8 zones |
TMF8821: Multizone with 3x3, 4x4 and 3x6 zones
TMF8820: Multizone with 3x3 zones
|Enable new applications like click to focus, object tracking, presence detection|
|Time-to-Digital Converter (TDC) |
Direct Time-of-Flight Measurement
|Within ±3% / ±10 mm of measurement (accuracy); |
No multipath and no multiple object problems as for iToF
|Single Photon Avalanche Photodiode (SPAD) |
Histogram based architecture
|Better accuracy detects reliably closest object |
Minimum distance 10 mm
Maximum distance 5000 mm
|Dynamic cover glass calibration||No complex calibration|
|Reliable operation under demanding use cases||Compensates for dirt on glass|
|Reference SPAD||Improved accuracy over temperature and life|
|Distance and signal quality reported||Make better decisions|
|Fast VCSEL driver with protection||Class 1 eye safe|
|I3C tolerant - operate on a shared I2C / I3C bus||Integration flexibility|
|141 mW power consumption at 30 Hz operation |
8 µA power consumption standby current (keep memory)
2 µA power-down current consumption (EN=0)
|Longer battery life|
- Distance measurement for camera autofocus - Laser Detect Autofocus - LDAF (mobile phone)
- Presence detection (computing and communication)
- Object detection and collision avoidance (robotics)
- Light curtain (industrial)
TMF8820/21/28 Block Diagram
TMF8820/21/28 Application Schematic
The TMF8820/21/28 needs only 3 small 0402 external capacitors for operation:
The SYNC signal connected to GPIO1 can be used to immediately interrupt the TMF8820/21/28 VCSEL operation if the high power illuminator is operating or to sync to a camera operation. Ensure that SYNC does not exceed the VDD supply of TMF8820/21/28 as otherwise an internal protection diode will start conducting. On SYNC assertion, the VCSEL is immediately switched off (typically after 10 µs), on SYNC de-assertion the VCSEL operation is resumed.
GPIO0 can be used as a general GPIO output signal.
The signals INT/SDA/SCL need an external pull-up resistor to the VIO supply (typically 1.8 V).
Evaluation Kit for TMF8820, TMF8821 & TMF8828
The TMF882X-EVM -- TMF882X Evaluation Kit comes with everything needed to evaluate the TMF8820, TMF8821 & TMF8828 multi-zone direct Time-of-Flight sensors. The evaluation kit comprises of a ToF sensor enclosure and sample glass, USB type A to micro-USB cable, USB Flash drive with EVM GUI software and EVM documentation.
TMF882X-EVM User Guide
TMF882X-EVM ToF EVM kit include: