MOTOROLA
MC68HC916X1
142
MC68HC916X1TS/D
1. Tested with a 4.194 MHz reference.
2. All internal registers retain data at 0 Hz.
3. Assumes that stable VDDSYN is applied, and that the crystal oscillator is stable. Lock time is measured from
the time VDD and VDDSYN are valid until RESET is released. This specification also applies to the period re-
quired for PLL lock after changing the W and Y frequency control bits in the synthesizer control register (SYN-
CR) while the PLL is running, and to the period required for the clock to lock after LPSTOP.
4. This parameter is periodically sampled rather than 100% tested.
5. Assumes that a low-leakage external filter network is used to condition clock synthesizer input voltage. Total
external resistance from the XFC pin due to external leakage must be greater than 15 M
to guarantee this
specification. Filter network geometry can vary depending upon operating environment.
6. Proper layout procedures must be followed to achieve specifications.
7. Internal VCO frequency (fVCO ) is determined by SYNCR W and Y bit values.
The SYNCR X bit controls a divide-by-two circuit that is not in the synthesizer feedback loop.
When X = 0, the divider is enabled, and fsys = fVCO ÷ 4.
When X = 1, the divider is disabled, and fsys = fVCO ÷ 2.
X must equal one when operating at maximum specified fsys.
8. Jitter is the average deviation from the programmed frequency measured over the specified interval at max-
imum fsys. Measurements are made with the device powered by filtered supplies and clocked by a stable ex-
ternal clock signal. Noise injected into the PLL circuitry via VDDSYN and VSS and variation in crystal oscillator
frequency increase the Jclk percentage for a given interval. When clock jitter is a critical constraint on control
system operation, this parameter should be measured during functional testing of the final system.
Table 76 Clock Control Timing
(V
DD
and V
DDSYN
= 5.0 Vdc
± 10 %, V
SS
= 0 Vdc, T
A
= T
L
to T
H
)
Num
Characteristic
Symbol
Min
Max
Unit
1
PLL Reference Frequency Range1
f
ref
3.2
4.2
MHz
2
System Frequency2
On-Chip PLL System Frequency Range
External Clock Operation
f
sys
dc
4(fref) /128
dc
16.78
MHz
3
PLL Lock Time
1, 3, 4, 5, 6
t
lpll
—
20
ms
4
VCO Frequency7
fVCO
—
2 (fsys max)
MHz
5
Limp Mode Clock Frequency
SYNCR X bit = 0
SYNCR X bit = 1
f
limp
—
f
sys
max/2
f
sys
max
MHz
6
Short term (5
s interval)
Long term (500
s interval)
J
clk
– 0.5
– 0.05
0.5
0.05
%
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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