
Electrical Specifications
MC68HC908QY/QT Family Data Sheet, Rev. 6
154
Freescale Semiconductor
16.8 5-V Oscillator Characteristics
Figure 16-4. RC versus Frequency (5 Volts @ 25C)
Characteristic
Symbol
Min
Typ
Max
Unit
Internal oscillator frequency(1)
1. Bus frequency, fOP, is oscillator frequency divided by 4.
fINTCLK
—12.8
—
MHz
Deviation from trimmed Internal oscillator (2)(3)
12.8 MHz, fixed voltage, fixed temp
12.8 MHz, VDD ± 10%, 0 to 70°C
12.8 MHz, VDD ± 10%, –40 to 125°C
2. Deviation values assumes trimming @25C and midpoint of voltage range
.
3. Values are based on characterization results, not tested in production.
ACCINT
—
± 0.4
± 2
—
± 5
%
Crystal frequency, XTALCLK(1)
fOSCXCLK
1—
24
MHz
External RC oscillator frequency, RCCLK(1)
fRCCLK
2—
12
MHz
External clock reference frequency(1) (4)
4. No more than 10% duty cycle deviation from 50%.
fOSCXCLK
dc
—
32
MHz
Crystal load capacitance(5)
5. Consult crystal vendor data sheet.
CL
—20—
pF
Crystal fixed capacitance(3)
C1
—
2 x CL
——
Crystal tuning capacitance(3)
C2
—
2 x CL
——
Feedback bias resistor
RB
0.5
1
10
M
Ω
RC oscillator external resistor
REXT
—
Crystal series damping resistor
fOSCXCLK = 1 MHz
fOSCXCLK = 4 MHz
fOSCXCLK = > 8 MHz
RS
—
20
10
0
—
k
Ω
0
2
4
6
8
10
12
14
0
10
2030
4050
60
R
EXT (kΩ)
RC
F
R
E
Q
UE
NCY
,f
RCCL
K(M
H
z)
5 V 25°C