SM8707 Datasheet, PDF (14/20 Pages) Nippon Precision Circuits Inc – Clock Generator with Dual PLLs

SM8707 series
FUNCTIONAL DESCRIPTION
27MHz Master Clock
The SM8707 series 27MHz master clock circuit is configured, as shown in Figure 3 and 4, with the crystal
oscillator element connected between XTI (pin 7) and XTO (pin 8).
Alternatively, the 27MHz master clock can be supplied from an external master clock input on XTI, as shown
in Figure 5 and 6.
If an external input clock on XTI is used, it is recommended that the frequency be 27.0000MHz, with 50%
duty, and 3.3V voltage amplitude level.
Furthermore, when using an external clock input, the input signal voltage should not exceed the absolute max-
imum rating, otherwise damage may occur.
C1
XTI (Pin 7)
Oscillator
C2
XTO (Pin 8)
C1, C2 = 5 to 33pF
Internal
Circuits
MO
C1
XTI (Pin 7)
Oscillator
C2
XTO (Pin 8)
C1, C2 = 5 to 33pF
Internal
Circuits
Figure 3. Crystal oscillator connection
(excluding SM8707K)
Figure 4. Crystal oscillator connection
(SM8707K)
External Clock _{XTI (Pin 7)}
Open
Oscillator
XTO (Pin 8)
Internal
Circuits
MO
Figure 5. External clock input
(excluding SM8707K)
External Clock _{XTI (Pin 7)}
Open
Oscillator
XTO (Pin 8)
Internal
Circuits
Figure 6. External clock input
(SM8707K)
NIPPON PRECISION CIRCUITS INC.—14