Datasheet

Page 14 ams Datasheet
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TMF8701 − Detailed Description
Reset Pin and Power-Up Timing
Figure 16:
Reset Pin and Power-Up Timing
Distance and Proximity Algorithm
As the performance of the algorithm is dependent on the ROM
version, following section only applies for devices with order
code TMF8701-1B (and TMF8701-1BM), calibrated and
in-application oscillator calibration using the reference driver
code and patched with the latest software patch from ams
(contact ams to identify latest patch version).
The TMF8701 is embedded in the application using a 0.38mm
airgap and a glass with an IR ink with >90% transmissivity. The
glass thickness is 0.5mm. An additional mask on the opaque ink
is implemented according to TMF8701 optical design guide
(external document).
Calibration
To achieve the performance described in the next sections, a
calibration of the algorithm needs to be performed
(command = 0x0A). The TMF8701 shall be embedded in the final
application and the cover glass including the IR ink needs to be
assembled. The calibration test shall be done in a housing with
minimal ambient light and no target within 40cm in FOI of the
TMF8701.
The TMF8701 generates a calibration data set which is
permanently stored on the host.
On each power-up of the TMF8701 the calibration data set is
sent by I²C to the TMF8701 prior to execution of any algorithms
(commands=0x02 or 0x0B).
Operating Modes and Timings
The TMF8701 can be operated in two different modes:
• Proximity mode only; it uses 80k iterations at 43Mhz for
capturing (VCSEL on).
• Proximity and distance mode combined; it uses 80k + 320k
iterations at 43Mhz for capturing.
Min Typ Max Units Comment
Power On (boot time) 3 ms
Does not include RAM
download time
Enable High to Ready for
Measurement
8ms
Standby to Active Time <<1 ms
Active to Standby Time <<1 ms
Enable Low to Power Down Time <<1 ms