xr82c684 Exar Corporation, xr82c684 Datasheet - Page 14

• Manufacturer Part Number: xr82c684
• Description: Cmos Quad Channel Uart Quart
• Manufacturer: Exar Corporation

AC ELECTRICAL CHARACTERISTICS
Notes
1
2
3
4
5
6
7
8
9
ABSOLUTE MAXIMUM RATINGS
Notes
1
Receiver Timing XR82C684 (Figure 66)
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 20 ns maxi-
mum. 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 = 50 pF, RL = 2.7 kohm to V
If -CS is used as the strobing input, this parameter defines the minimum high time between -CSs.
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 -CS and -IACK low, guaranteeing that they will be low for at least one CLK period.
This parameter is specified only to insure that -DTACK is asserted with respect to the rising edge of X1/CLK as shown in the timing
diagram, not to guarantee operation of the part. If the specified setup time is violated, -DTACK may be asserted as shown or may be
asserted one clock cycle later.
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.
XR82C684
Symbol
Parameter
1
1, 2, 3


(CONT’D)
Min.


Typ.
CC
.
Max.
Unit
Conditions
CC
= 5V and typical