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