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XR88C681
11
Rev. 2.11
AC ELECTRICAL CHARACTERISTICS 1, 2, 3 (CONT’D)
Test Conditions:
TA = 0 - 70°C, VCC = 5V 5% unless otherwise specified.
Symbol
Parameter
Min.
Typ.
Max.
Unit
Conditions
Clock Timing (Figure 56) (Cont’d.)
tCTC
Counter/Timer External Clock
High or Low Time (IP2)
100
ns
tCTC
Counter/Timer External Clock
Frequency
0
7.372
MHz
tRTX
RXCn and TXCn (External) High
or Low Time8
220
ns
fRTX
RXCn and TXCn (External)
Frequency
16X
1X
0
16.0
1.0
MHz
Transmitter Timing (Figure 57)
tTXD
TXD Output Delay - TXC
(External) Low
350
ns
tTCS
TXD Output Delay - TXC
(Internal) Output Low
150
ns
tRXS
RXD Data Setup Time to RXC
(External) High
240
ns
tRXH
RXD Data Hold Time from RXC
(External) High
200
ns
Notes
1.Parameters are valid over the specified temperature and operating supply ranges. Typical values are 25°C, VCC = 5V and typical
processing parameters.
2.All voltages are referenced to ground (GND). For testing, input signal levels are 0.4V and 2.4V with a transition time of 20ns
maximum. All time measurements are referenced at input voltages of 0.8V and 2.0V as appropriate. See Figure 50.
3.AC test conditions for outputs: CL = 50pF, RL = 2.7k to VCC.
4.If -CS is used as the strobing input, this parameter defines the minimum high time between -CSs.
5.Consecutive write operations to the same register require at least three edges of the X1 clock between writes.
6.This specification imposes a 6 MHz maximum 68000 clock frequency if a read or write cycle follows immediately after the previous
read or write cycle. A higher 68000 clock can be used if this is not the case.
7.This specification imposes a lower bound on -CS and -IACK low, guaranteeing that they will be low for at least one CLK period.
8.The minimum high time must be at least 1.5 times the X1/CLK period and the minimum low time must be at least equal to the X1/CLK
period if either channel’s Receiver is operating in external 1X clock mode.
Specifications are subject to change without notice
ABSOLUTE MAXIMUM RATINGS1
DC Supply Voltage
7V
. . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature
-65° C to 150° C
. . . . . . . . . . . . .
All Voltages with
respect to Ground2
-0.5V to +7V
. . . . . . . . . . . . . . . . . .
1.Stresses above those listed under the Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rat-
ing only, and functional operation of the device at these or any other conditions above those indicated in the “Electrical Characteris-
tics” section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.