ML7406 Family LSIs Hardware Design Manual
FEXL7406DG-01
3
2. Clock Input
2.1. Crystal Oscillator circuit [ML7406C]
Figure 2.1 shows a configuration example of the crystal oscillator circuit.
Capacitors should be connected to XIN (#5) and XOUT (#6) pins to stabilize 26MHz crystal oscillator circuit. To
determine the component values, the oscillator circuit evaluation on your designing board is required, since the
stray capacitor of the board will be influenced.
Amplitude level, oscillation margin, frequency accuracy and oscillator circuit start-up time should be considered
and evaluated.
Figure 2.1 Crystal Oscillator circuit configurations
2.1.1. Circuit component values for crystal oscillator circuit
It is recommended to ask your oscillator manufacturer to evaluate the matching component values on the
assembled board. The following tables show the matching component values with LAPIS Semiconductor RF
board as reference.
Table 2.1.1 Representative matching component values
Oscillator
Type
Frequency
(MHz)
Equivalent
series resister
max[Ω]
Load
capacitor
(pF)
Component
Values
Operating Condition
C1(pF) C2(pF)
Power supply
voltage range
VDDIO(V)
Temperature
range
( C)
FCX-05
26
100
7
2.7
2.7
1.8 to 3.6
-40 to +85
NX2520SA
26
60
8
1
1
1.8 to 3.6
-40 to +85
[Note] These component values appropriate for use on the LAPIS Semiconductor’s RF board. It is not guaranteed
to obtain same result on your specific board.
X
IN
(#
５
)
C1
X
’tal
X
OU
T(
#
６
)
C2