NE83C92 NXP Semiconductors, NE83C92 Datasheet - Page 7

• Manufacturer Part Number: NE83C92
• Description: Low-power Coaxial Ethernet Transceiver
• Manufacturer: NXP Semiconductors

Philips Semiconductors
POR/Under Voltage Lockout/AUI Selection
The transmit and receive squelch circuits of the NE83C92 remain
active if the absolute value of V
under voltage lockout, V
on either the AUI or coaxial cable during power up and power down.
There is no collision announcement during power up and the
transceiver waits for 400ms before becoming enabled.
If RXI is disconnected from the coaxial cable after power-up, its
voltage will fall towards VEE. If the absolute value of this voltage
exceeds the AUI disable voltage, VDIS, for longer than 800ms, the
transmit and receive squelch circuits remain active and, in addition,
the AUI drivers become high impedance. This permits AUI
connections to be hard wired together, e.g., the coaxial transceiver
and 10BASE-T transceiver, with the signal path determined by
which transceiver is connected to its external cable.
There is a 400ms collision announcement on disconnecting RXI, but
there is no announcement on re-connection. This feature can be
disabled by pulling RXI up with a 200k to ground.
1995 May 1
Low-power coaxial Ethernet transceiver
12 TO 15V DC
COLLISION
TRANSMIT
RECEIVE
NOTES:
1. T1 is a 1:1 pulse transformer, with an inductance of 30 to 100 H.
2. IN916 or equivalent for Ethernet, not required for Thin Ethernet.
3. 78 resistors not required if AUI cable not present.
4. Not required for optimal integrated/local MAU application (No AUI cable, see Note 3), minimum current consumption.
5. Install 200k to disable the 400ms collision announcement when disconnecting cable.
PAIR
PAIR
PAIR
78
(NOTE 3)
78
UVL
CABLE
. This prevents glitches from appearing
AUI
EE
is less than the threshold for
Figure 1. Connection Diagram for Standard 8392 Applications
T1 (NOTE 1)
CONVERTER
1
2
4
5
7
8
DC TO DC
<200mA
16
15
13
12
10
9
78
7
Detection of Coaxial Cable Faults
In the NE83C92 there is no internal loopback path from the TX
inputs to the RX outputs. This means that, when the local DTE is
transmitting, the signal will only be present at the receiver outputs
RX+ and RX– if it appears on the coaxial cable and is larger than
the receiver squelch threshold V
occurs at the cable connector to the CTI, then no signal will appear
at the receiver outputs.
In the case of an open circuit at the coaxial cable connector there
will also be no signal at the receiver outputs due to the AUI disabling
mode of the NE83Q92. However, a heartbeat signal will be present
following a transmission attempt for the short circuit condition, but
not for the open circuit.
A coaxial cable with only a single 50 termination will generate a
collision not only at every transmission attempt, but also for every
reception attempt due to the receive mode collision detection of the
NE83C92.
CD+
CD–
RX+
V
V
TX+
RX–
TX–
EE
EE
1
2
3
4
5
6
7
8
NE83C92
9V (ISOLATED)
CTI
+
–
16
15
14
13
12
11
10
500
500
500
500
9
CDS
TXO
RXI
V
RR–
RR+
GND
HBE
EE
RS
1k 1%
(NOTE 4)
. If a short circuit fault condition
(NOTE 2)
200k
(NOTE 5)
Product specification
NE83C92
SD00309
COAX