XR88C681CP/40-F Exar Corporation, XR88C681CP/40-F Datasheet - Page 59

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XR88C681CP/40-F

Manufacturer Part Number
XR88C681CP/40-F
Description
IC UART CMOS DUAL 40PDIP
Manufacturer
Exar Corporation
Type
CMOS Dual Channel UARTr
Datasheet

Specifications of XR88C681CP/40-F

Number Of Channels
2, DUART
Package / Case
40-DIP (0.600", 15.24mm)
Features
*
Fifo's
1 Byte, 3 Byte
Voltage - Supply
5V
With Parallel Port
Yes
With Cmos
Yes
Mounting Type
Through Hole
Data Rate
1 Mbps
Supply Voltage (max)
5.25 V
Supply Voltage (min)
4.75 V
Supply Current
15 mA
Maximum Operating Temperature
+ 70 C
Minimum Operating Temperature
0 C
Mounting Style
Through Hole
Operating Supply Voltage
5 V
Propagation Delay Time Ns
400 ns
No. Of Channels
2
Supply Voltage Range
4.75V To 5.25V
Operating Temperature Range
0°C To +70°C
Digital Ic Case Style
DIP
No. Of Pins
40
Filter Terminals
DIP
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Lead Free Status / RoHS Status
Lead free / RoHS Compliant, Lead free / RoHS Compliant
Other names
1016-1328-5

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
XR88C681CP/40-F
Manufacturer:
Linear
Quantity:
185
In general the bit-error-rate, for this “uncorrected” system
is a function of the timing differences between the TX and
RX local clock signals. However, in order to correct for
Receiver Drift and to minimize the BER during serial data
transmission, many UARTs in the market place, employ
Receiver Oversampling of the START bit. When this
feature is employed, the Receiver, upon detection of the
START bit, will begin oversampling this START bit by
some integer factor. Typically, for most present day
UARTs, this over-sample factor is 16. (The XR88C681
device also accommodates 16X receiver oversampling of
the START bit). Therefore, in these devices, when the
Receiver detects the occurrence of a START bit, it (the
Receiver) will begin oversampling this START bit by a
Rev. 2.11
Figure 32. The Typical Sampling Pattern of Each Receiver Within the XR88C681 Device.
7- 16X clock
periods
the Midpoint
Chosen as
of the Bit
1 Bit Period
59
factor of 16. However, after 7 16X clock periods has
elapsed, the receiver will assume this point (within the
START bit) to be the mid point of the bit period, and will
cease oversampling of the START bit and of the
subsequent data. From this point, through the end of the
character, the Receiver will sample the serial data stream
at the 1X rate. Stated another way, once the Receiver has
reached, what it believes to be the mid-point of the START
bit, the receiver will, from that point, begin sampling the
serial data at 1-bit period interval (see Figure 32). After
the Receiver has received the STOP bit, it will await the
occurrence of the START bit. Once the START bit has
been detected, this oversampling procedure is repeated.
XR88C681

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