XR88C681J-F Datasheet, PDF (11/101 Pages) Exar Corporation – Two Full Duplex, Independent Channels

XR88C681
AC ELECTRICAL CHARACTERISTICS ^{1, 2, 3} (CONT’D)
Test Conditions: T_A = 0 - 70°C, V_CC = 5V ¦ 5% unless otherwise specified.
Symbol
Parameter
Min.
Typ. Max.
Unit Conditions
Clock Timing (Figure 56) (Cont’d.)
t_CTC
Counter/Timer External Clock
100
High or Low Time (IP2)
t_CTC
Counter/Timer External Clock
0
Frequency
t_RTX
RXCn and TXCn (External) High 220
or Low Time⁸
f_RTX
RXCn and TXCn (External)
Frequency
16X
0
1X
0
Transmitter Timing (Figure 57)
t_TXD
TXD Output Delay - TXC
(External) Low
t_TCS
TXD Output Delay - TXC
(Internal) Output Low
t_RXS
RXD Data Setup Time to RXC
240
(External) High
t_RXH
RXD Data Hold Time from RXC
200
(External) High
7.372
ns
MHz
ns
16.0
MHz
1.0
MHz
350
ns
150
ns
ns
ns
Notes
1._{Parameters are valid over the specified temperature and operating supply ranges.}
processing parameters.
Typical values are 25°C, V_CC
= 5V and typical
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.
Rev. 2.11
11