SLVSJQ6 September 2025 TMF0064
PRODUCTION DATA
The TMF0064 is a low-power device that only needs to turn on when communicating. The device power comes from the voltage supply used for digital I/O in the system. A dedicated VCC pin does not exist in the device; there is not a requirement of a supply input bypass capacitor. The device obtains power from the SDQ communication input which is sustainable during normal communication activity.
The ramp time of the SDQ voltage when power is initially applied can be slow due to current limiting from the source. Ramp times greater than 200µs can cause undesired bouncing of the POR circuit and result in the device not generating a presence pulse. To account for this undesired effect on the device, a best practice for the communication host is to issue a hard reset to the device by pulling down the SDQ line for >5ms and then releasing the SDQ bus before issuing the reset pulse that is approximately 480µs long.
Figure 7-4 illustrates the best practice for dealing with initial power on ramps.
Figure 7-4 Power-Up Best Practice