Datasheet

MCF51AC256 ColdFire Microcontroller Data Sheet, Rev.7
Electrical Characteristics
Freescale Semiconductor32
2.10 MCG Specifications
Table 16. MCG Frequency Specifications (Temperature Range = –40 to 105 C Ambient)
Num C Rating Symbol Min Typical
1
Max Unit
1C
Internal reference frequency — factory trimmed at
V
DD
= 5 V and temperature = 25 C
f
int_ft
— 32.768 — kHz
2 C Average internal reference frequency — untrimmed f
int_ut
31.25 — 39.0625 kHz
3 T Internal reference startup time t
irefst
—60 100s
4
C
DCO output frequency
range — untrimmed
2
Low range (DRS=00)
f
dco_ut
16 — 20
MHzC Mid range (DRS=01) 32 — 40
C High range (DRS=10) 48 — 60
5
P
DCO output frequency
2
reference =32768Hz
and DMX32 = 1
Low range (DRS=00)
f
dco_DMX32
— 16.82 —
MHzP Mid range (DRS=01) — 33.69 —
P High range (DRS=10) — 50.48 —
6D
Resolution of trimmed DCO output frequency at fixed
voltage and temperature (using FTRIM)
f
dco_res_t
— 0.1 0.2 %f
dco
7D
Resolution of trimmed DCO output frequency at fixed
voltage and temperature (not using FTRIM)
f
dco_res_t
— 0.2 0.4 %f
dco
8D
Total deviation of trimmed DCO output frequency over
voltage and temperature
f
dco_t
—
0.5
–1.0
2%f
dco
9D
Total deviation of trimmed DCO output frequency over
fixed voltage and temperature range of 0–70
C
f
dco_t
— 0.5 1%f
dco
10 D FLL acquisition time
3
t
fll_acquire
—— 1 ms
11 D PLL acquisition time
4
t
pll_acquire
—— 1 ms
12 D
Long term jitter of DCO output clock (averaged over
2ms interval)
5
C
Jitter
—0.02 0.2%f
dco
13 D VCO operating frequency f
vco
7.0 — 55.0 MHz
16 D Jitter of PLL output clock measured over 625 ns
6
f
pll_jitter_625ns
—0.566
6
—%f
pll
17 D Lock entry frequency tolerance
7
D
lock
1.49 — 2.98 %
MCU
EXTAL XTAL
Crystal or Resonator
R
S
C
2
R
F
C
1