Product data

HD404818 Series
39
Table 18 Examples of Oscillator Circuits (cont)
Circuit Configuration Circuit Constants
Crystal oscillator
X1
C
1
2
C
X2
Crystal
GND
L
S
C
R
S
C
0
Crystal: 32.768 kHz: MX38T
(Nippon Denpa Kogyo)
C
1
: = 20 pF ± 20%
C
2
: = 20 pF ± 20%
R
S
: = 14 kΩ
C
0
: = 1.5 pF
Notes: 1. The circuit parameters above are recommended by the crystal or ceramic oscillator
manufacturer. The circuit parameters are affected by the crystal or ceramic oscillator and floating
capacitance when designing the board. When using the oscillator, consult with the crystal or
ceramic oscillator manufacturer to determine the circuit parameters.
2. Writing among OSC
1
and OSC
2
or X1 and X2, and other elements should be as short as
possible, and should not cross other wires. Refer to figure 21.
3. When the 32.768-kHz crystal oscillator is not used, pin X1 must be fixed to V
cc
and pin X2 must
be left open.