Precision in a flash with direct time of flight sensing
Let’s talk about the TMF8806’s power efficiency in a little more detail. The sensor can operate in ultra-low power modes, consuming as little as 14 µA at a 0.5 Hz measurement rate. Even at 30 Hz, power consumption remains at just 27 mA. Because the TMF8806 features extremely fast startup — less than 5 ms — it allows users to switch the device off between measurements. Users can control the duty cycle from their host microcontrollers, which currently operate in sub-microamp modes. In other words, by using the microcontroller to wake up the sensor, take a measurement and go back to sleep, users can achieve highly efficient duty cycles and overall power consumption. The TMF8806 also offers greater design flexibility. It supports multiple optical configurations, including a default mode optimized for minimal cover glass, a large air gap mode allowing up to 20 mm between the sensor and the outer surface, and a thick cover glass mode that supports protective layers up to 3.2 mm thick. This adaptability makes the sensor ideal for industrial applications, where thicker glass and greater mechanical tolerances are common. It is generally recommended to include an optical barrier or isolator between the cover glass and the sensor, as this helps to reduce production tolerances and improve performance.
A sample histogram demonstrating multiple pulses of light. (Image: ams OSRAM.)
While the sensor won’t be fazed by a little dust or smudge on the cover glass, excessive buildup can degrade performance over time. Furthermore, the number of measurements taken per second varies by application. For instance, a video camera autofocus system may require 30 measurements per second, while presence detection in a smart appliance may need only a few per second. Higher measurement rates increase power consumption due to the higher number of VCSEL pulses. Single-zone dToF sensors focus on detecting the closest object within a fixed field of view. Due to their compact nature, single-zone dToF sensors are generally well-suited to systems where space and power is limited.
Introducing the TMF8806 sensor
The TMF8806 from ams OSRAM is a single-zone dToF sensor designed to detect objects from as close as 1 cm to as far as 10 m. Within its tiny footprint of just 2.2 × 3.6 × 1 mm, the device includes a VCSEL emitter, SPAD array, TDC and on-chip histogram processing in one fully integrated module, making it easy to implement in various settings. One of the key improvements in the TMF8806 is its expanded distance sensing capability. The sensor operates in standard 2.5-meter and 5-meter modes without requiring a firmware download, leading to faster startup and more power-efficient operation. A firmware update enables the extended 10-meter range for applications requiring longer-distance sensing.
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