MC68HC908GR8 Datasheet, PDF (255/286 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Clock Generation Module Characteristics
23.8 Clock Generation Module Characteristics
23.8.1 CGM Component Specifications
Characteristic
Crystal reference frequency
Crystal load capacitance⁽¹⁾
Crystal fixed capacitance⁽²⁾
Crystal tuning capacitance⁽²⁾
Feedback bias resistor
Series resistor⁽³⁾
Symbol
Min
Typ
f_XCLK
30
32.768
C_L
—
12.5
C₁
—
15
C₂
—
15
R_B
1
10
R_S
100
330
1. Crystal manufacturer value.
2. Capacitor on OSC1 pin. Does not include parasitic capacitance due to package, pin, and board.
3. Capacitor on OSC2 pin. Does not include parasitic capacitance due to package, pin, and board.
Max
Unit
100
kHz
—
pF
—
pF
—
pF
22
MΩ
470
kΩ
23.8.2 CGM Electrical Specifications
Description
Operating voltage
Operating temperature
Crystal reference frequency
Range nominal multiplier
VCO center-of-range frequency⁽¹⁾
Medium-voltage VCO center-of-range frequency⁽²⁾
VCO range linear range multiplier
VCO power-of-two range multiplier
VCO multiply factor
VCO prescale multiplier
Reference divider factor
VCO operating frequency
Bus operating frequency⁽¹⁾
Bus frequency @ medium voltage⁽²⁾
Manual acquisition time
Automatic lock time
Symbol
V_DD
T
f_RCLK
f_NOM
f_VRS
f_VRS
L
2^E
N
2^P
R
f_VCLK
f_BUS
f_BUS
t_Lock
t_Lock
PLL jitter⁽³⁾
f_J
External clock input frequency PLL disabled
External clock input frequency PLL enabled
f_OSC
f_OSC
1. 5.0 V ± 10% V_DD
2. 3.0 V ± 10% V_DD
3. Deviation of average bus frequency over 2 ms. N = VCO multiplier.
Min
2.7
–40
30
—
38.4 k
38.4 k
1
1
1
1
1
38.4 k
—
—
—
—
0
dc
30 k
Typ
—
25
32.768
38.4
—
—
—
—
—
1
1
—
—
—
—
—
—
—
—
Max
5.5
125
100
—
40.0 M
40.0 M
255
4
4095
8
15
40.0 M
8.2
4.1
50
50
f_RCLK x
0.025% x
2^P N/4
32.8 M
1.5 M
Unit
V
o_C
kHz
kHz
Hz
Hz
Hz
MHz
MHz
ms
ms
Hz
Hz
Hz
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
Freescale Semiconductor
255