IC-TW4 Datasheet, PDF (12/14 Pages) IC-Haus GmbH – PROGRAMMABLE INTERPOLATOR WITH AUTOMATIC OFFSET CORRECTION

iC-TW4 PROGRAMMABLE INTERPOLATOR
WITH AUTOMATIC OFFSET CORRECTION
START UP
Volts V
DD
3.3 or 5.0 V
Rev D1, Page 12/14
1.8 V
0.0 V
Time
Power- On- Reset releases,
iC-TW4 starts configuration
35 ms
iC-TW4 starts operation.
Figure 7: Power supply ramp-up
The iC-TW4 contains built-in Power-On-Reset (POR)
circuitry. The POR keeps the device in reset as long
as the applied power supply voltage does not allow
reliable operation. Once the power supply ramps up
above 1.8 V, the POR releases the reset and the iC-
TW4 starts the configuration cycle. 35 ms after the de-
vice goes out of reset, normal operation begins.
The A/B signals on start-up follow reproducible the sta-
ble input signal state with a stable A/B output state. No
A/B bursts are output on start-up with a stable input
signal state. The state of the A/B output signals is de-
fined by the absolute sensor position within a period.
The phase relationship between Z and A/B is defined
and persists.
Due to hysteresis it is possible that the A/B output dif-
fers on start-up from the levels on power down.
To avoid A/B output toggling while startup it is impor-
tant that the power supply ramp-up is sufficiently fast
and the input signals are stable as soon as normal op-
eration begins. In applications where startup A/B tog-
gling is acceptable, no precaution must be taken, as
the iC-TW4 will properly power-up on an indefinitely
slow supply rise time.