STLC60134S View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'STLC60134S' PDF : 22 Pages View PDF
Table 21. VCXO circuit Characteristics
Symbol
fa bs
frange
IO
Parameter
Absolute frequency accuracy
Frequency Tuning Range
VCXO Output Current
Min.
-15ppm
Nominal
35.328MHz
±50ppm
100µA
Ii
Reference Input Current
100µA
N.B: frequency tuning range is proportional to the crystal dynamic capacitance Cm.
STLC60134S
Max.
+15ppm
1mA
Note
Rref = 16.5kΩ
AVDD = 3.3V
AVDD = 3.3V
Figure 11. Principle of VCXO control
8 bits
CTRLIN
DAC
AVDD
CS
VCOCX
1MΩ
±30%
Filtered VCXO
(se e CTRLIN table)
Clk3 5
AVDD/22÷AVDD/2
I VCO
RR EF
Ii
AVDD
VCXOUT
IO=Ii
XTALO
CP
Ct
AGND
Rt
XTALI
-1 5V
D98TL364mod
The tuning must be monotonic with 8-bit resolution with the worst-case tuning step of <2ppm/LSB (8-bit).
The time constant of the tuning must be variable from 5s to 10s through an external capacitor Cs (R =
1MΩ ±30%). This determines the speed of the VCXO in normal operation (slow speed in ”show time”)
with filtered VCXO. For faster tracking, the previous filter is not used and the speed depends on CtRt.
13/22
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