ICS82C404 Datasheet, PDF (9/13 Pages) Integrated Circuit Systems – Dual Programmable Graphics Frequency Generator

ICS82C404
Electrical Characteristics (continued)
AC Characteristics
DESCRIPTION
NAME
SYMBOL MIN
TYP
MAX
Reference oscillator value (Note 1) Reference
frequency
1/fREF
Duty cycle for the input oscillator
defined as t1/tREF
Output oscillator values
Reference period
Input duty cycle
Output clock
periods
Duty cycle for the output oscillators Output duty cycle
(Note 2)
Rise time for the output oscillators Rise times
into a 25pF load
Fall time for the output oscillators
into a 25pF load
Fall times
Old frequency output
freq1 output
New frequency output
freq2 output
Time clock output remains high while fREF mux time
output muxes to reference frequency
Interval for serial programming and Time-out interval
for VCO changes to settle (Note 3)
Time clock output remains high while tfreq2muxtime
output muxes to new frequency value
Time for the output oscillators to go Tristate
into tristate mode after OUTDIS-
signal assertion
Time for the output oscillators to
recover from tristate mode after
OUTDIS-signal goes high
CLK valid
Time for power-down mode of
operation to take effect
Power-Down
Time for recovery from power-down Power-Up
mode to a valid CLK
Time for MCLK to go high after
PWRDWN is asserted high
MCLKOUT high
Delay of MCLK prior to fMCLK
signal at output
MCLKOUT delay
Clock period of serial clock
Set-up time
Hold time
Load command
fREF
1
14.31818
60
tREF
16.6
t1
25%
1000
75%
t2
8.33
(120 MHz)
t3
45%
2564
(390 kHz)
55%
t4
3
t5
3
tfreq1
tfreq2
tA
ttime-out
0.5t_REF
2
1.5t_REF
5
10
tB
0.5 _tREF
1.5 _tREF
t6
12
t7
12
t8
t9
t10
0
t11
tserclk
tSU
tHD
tldcmd
0.5 _tMCLK
2 • tREF
20
10
0
12
12
tPWRDWN
1.5 _tMCLK
2
t1+30
UNITS
MHz
ns
ns
ns
ns
ns
ms
ns
ns
ns
ns
ns
ns
ns
ms
ns
ns
ns
Notes:
1. For reference frequencies other than 14.81818 MHz, the pre-loaded ROM frequencies will shift proportionally.
2. Duty cycle is measured at CMOS threshold levels. At 5 volts, VTH=2.5 volts.
3. If the interval is too short, see the time-out interval section in the control register definition.
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