AS3930
Datasheet - Detailed Description
8.8.3 External Clock Source
To clock the AS3930 with an external signal the crystal oscillator has to be enabled (R1<0>=1). As shown in Figure 3, the clock must be applied
on the pin XIN while the pin XOUT must stay floating. The RC time constant has to be 100μs with a tolerance of ±10% (e.g. R=680 kΩ and
C=22pF). In Table 25, the clock characteristics are summarized.
Table 25. Characteristics of External Clock
Symbol
Parameter
Min
Typ
Max
Units
VI
Low level
0
0.1*VDD
V
Vh
High level
0.9*VDD
VDD
V
Tr
Rise-time
3
µs
Tf
Fall-time
3
µs
T=1/2πRC
RC Time constant
90
100
110
µs
Note: In power down mode the external clock has to be set to VDD.
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