xr88c681 Exar Corporation, xr88c681 Datasheet - Page 11

• Manufacturer Part Number: xr88c681
• Description: Cmos Dual Channel Uart Duart
• Manufacturer: Exar Corporation

AC ELECTRICAL CHARACTERISTICS
Test Conditions: T
Notes
1.
2.
3.
4.
5.
6.
7.
8.
ABSOLUTE MAXIMUM RATINGS
DC Supply Voltage
Storage Temperature
All Voltages with
respect to Ground
1.
Clock Timing (Figure 56) (Cont’d.)
Transmitter Timing (Figure 57)
Parameters are valid over the specified temperature and operating supply ranges. Typical values are 25°C, V
processing parameters.
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.
AC test conditions for outputs: CL = 50pF, RL = 2.7k
If
Consecutive write operations to the same register require at least three edges of the X1 clock between writes.
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.
This specification imposes a lower bound on
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.
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.
Symbol
-
CS is used as the strobing input, this parameter defines the minimum high time between
t
t
t
t
f
t
t
t
Rev. 2.11
RXH
CTC
CTC
RTX
RTX
TXD
TCS
RXS
Counter/Timer External Clock
High or Low Time (IP2)
Counter/Timer External Clock
Frequency
RXCn and TXCn (External) High
or Low Time
RXCn and TXCn (External)
Frequency
16X
1X
TXD Output Delay - TXC
(External) Low
TXD Output Delay - TXC
(Internal) Output Low
RXD Data Setup Time to RXC
(External) High
RXD Data Hold Time from RXC
(External) High
2
A
. . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . .
= 0 - 70°C, V
. . . . . . . . . . . . .
Parameter
8
1
CC
Specifications are subject to change without notice
-65° C to 150° C
= 5V ¦ 5% unless otherwise specified.
1, 2, 3
-0.5V to +7V
-
CS and
(CONT’D)
Min.
100
220
240
200
0
0
0
-
IACK low, guaranteeing that they will be low for at least one CLK period.
7V
to V
CC
Typ.
11
.
7.372
Max.
16.0
350
150
1.0
MHz
MHz
MHz
Unit
ns
ns
ns
ns
ns
ns
Conditions
-
CSs.
XR88C681
CC
= 5V and typical