ML145026, ML145027, ML145028
LANSDALE Semiconductor, Inc.
This oscillator operates at a frequency determined by the
external RC network; i.e.,
2.3 RTC CTC′
for 1 kHz ≤ f ≤ 400 kHz
where: CTC′ = CTC + Clayout + 12 pF
RS ≈ 2 RTC
RS ≥ 20 k
RTC ≥ 10 k
400 pF < CTC < 15 µF
The value for RS should be chosen to be ≥ 2 times RTC. This range ensures
that current through RS is insignificant compared to current through RTC. The
upper limit for RS must ensure that RS x 5 pF (input capacitance) is small com-
pared to RTC x CTC.
For frequencies outside the indicated range, the formula is less accurate.
The minimum recommended oscillation frequency of this circuit is 1 kHz. Sus-
ceptibility to externally induced noise signals may occur for frequencies below
1 kHz and/or when resistors utilized are greater than 1 MΩ.
Figure 9. Encoder Oscillator Information
2 WORD TRANSMISSION
Figure 10. Timing Diagram
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