3. DISABLE Pin Timing
For a part that has a DISABLE pin, DISABLE high will put the part in complete sleep mode with I
DD
typical of 100 nA. When DISABLE
goes low, the part will wake and initiate a measurement. For a single measurement, this takes 11 μsec typically. Additional measure-
ments in a burst take 8.8 μsec. Once the measurement (burst) is complete, the output pin status is updated and the part enters idle
mode. The part will make a new measurement or measurement burst at the time-interval determined by the idle timer (typically 1 msec).
The idle timer is reset when DISABLE transitions from high to low, so the time from the first measurement until the next measurement
will always be the programmed idle time.
Disable low pulses can be as short as 1 μsec. For pulses shorter than a conversion burst, the part will make one burst and then go back
to sleep.
When disable returns high, a measurement in progress (if any) will complete and the part will enter sleep mode.
As the idle time is typically long (i.e. 1 msec) compared to the measurement time (i.e. 11 μsec), it is possible to keep the DISABLE pin
low duration short (i.e. 15 μsec) and have a long period in the sleep state. This is an effective way to control the sample rate and power.
For example, if the part is programmed to make a single measurement at a time and is programmed with an idle time of 1 msec and
DISABLE is pulsed low for 15 μsec every 50 msec, then the average I
DD
will be:
• 11 μsec to wake and make a measurement at I
DD
typical of 5.0 mA (3.3V)/(50.015 msec cycle time) = 1.0 μA
• 4 μsec in idle mode at typical current of 360 μA/(50.015 msec cycle time) = 0.03 μA
• 50 msec in sleep mode at 50 nA/(50.015 msec cycle time) = 0.05uA
• Or 1.08 μA total
As the programmed idle time is shorter than the DISABLE low time in the example, the value of the programmed idle time does not
make a difference.
Si720x Switch/Latch Hall Effect Magnetic Position Sensor Data Sheet
DISABLE Pin Timing
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