MTD492 View Datasheet(PDF) - Myson Century Inc
Part Name
Description
Manufacturer
MTD492 Datasheet PDF : 8 Pages
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MYSON
TECHNOLOGY
1.0 CONNECTION DIAGRAM
CD+
CD-
RX+
VEE
VEE
RX-
TX+
TX-
1
24
2
23
3
22
4 MTD492N 21
5 16 PIN PDIP 20
6
19
7
18
8
17
CDS
TX0
RXI
VEE
RR-
RR+
GND
HBE
VEE
VEE
VEE
VEE
VEE(NC)
VEE(NC)
VEE(NC)
MTD492V
28 PIN PLCC
MTD492
VEE(NC)
VEE
VEE
VEE
VEE
VEE(NC)
RR-
2.0 PIN DESCRIPTIONS
Name I/O
TX+,TX- I
HBE I
RR+,RR- I
RXI I
CDS I
CD+,CD- O
PDIP
Pin#
7,8
9
11,12
14
16
1,2
PLCC
Description
Pin#
13,14 Transmission Data Input. A balanced differential line receiver which
receives inputs from the off-chip Manchester Code Converter(MCC) to
the Transmitter. The common mode voltage on TX+ is set internally .
15 Heartbeat Enabler. The CD heartbeat test is enabled when HBE is
connected to Ground and disabled when HBE is connected to VEE.
This pin is internally biased at 0.5 VEE. Test mode is enabled if this
pin is left floating or biased in the range of -3.5V to -5.5V. Jabber is
disabled in test mode. Exiting the jabber disable mode requires at
least jabber reset time.
18,19 External Resistor. A 1kΩ/1% resistor should be connected across
these pins to correctly set internal operating currents. RR+ is
internally shorted to GND.
26 Network Receiving Input. Should be connected to the COAX center
conductor. Signals meeting receiver squelch limits are recovered and
output on RX+. RXI also detects the collision voltage level.
1 Collision Detection Sense. Connects directly to the COAX
shield, providing a reference for the collision detection voltage
level for reception-mode detection. An external bias network can be
used to shift the detection threshold for transmission-detection mode.
2,3 Collision Output. A balanced differential line driver drives this
output pair from the collision detection circuitry. A 10MHz signal from
the internal oscillator is transferred to these outputs in the event of
collision, excessive transmission (jabber), or during heartbeat
condition. These outputs are open sources, and pull-down resistors of
510Ω to VEE are required. To minimize power dissipation, both open
source outputs are disabled during idle condition, allowing the
common mode on the pull-down resistors to be pulled to VEE.
MTD492 Revision 3.5 01/07/1997
2/8
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