mc68160b Freescale Semiconductor, Inc, mc68160b Datasheet - Page 21

• Manufacturer Part Number: mc68160b
• Description: Enhanced Ethernet Transceiver
• Manufacturer: Freescale Semiconductor, Inc

AUI TRANSMIT SWITCHING
NOTE: Load on specified output is a shunt 27 H inductor and 83
AUI RECEIVE SWITCHING
Squelching Characteristics
The receive data pairs and the collision pairs should have the following squelch characteristics:
1. The squelch circuits are on at idle (with input voltage at approximately 0 V differential).
2. If an input is in squelch, pulse is rejected if the peak differential voltage is more positive than –175 mV, regardless of pulse width.
3. A pulse is considered valid if its peak differential voltage is more negative than –300 mV and its width, measured at –285 mV, is > 25 ns.
4. The squelch circuits are disabled by the first valid negative differential pulse on either the AUI receive data or collision pair.
5. If a positive differential pulse occurs on either the AUI receive data or collision pair > 175 ns, end of frame is assumed and squelch circuitry is turned on.
MOTOROLA ANALOG IC DEVICE DATA
TCLK to ATX Pair Steady State Propagation Delay
Output Differential Rise and Fall Times (Measured directly at device pins)
ATX Bit Cell Duration center–to–center (Measured directly at device pins)
ATX Half–Bit Cell Duration center–to–boundary (Measured directly at device pins)
ATX Pair Held at Positive Differential at start of Idle (Measured through
ARX/ACX Differential Input Voltage Range
ARX/ACX Differential Input Pulse Width to:
RENA Assertion Delay
RENA Deassertion Delay
transformer)
Initiate Data Reception
Inhibit Data Reception
(Logic Levels)
Differential
ATX+/–
TENA
TCLK
TX
Characteristic
Characteristic
1.5V
1
t 240
0V
Input Voltage
Figure 31. ATX Transmit Timings
Differential
0
1
Figure 32. ARX/ACX Timing
ARX+/–
ACX+/–
resistor.
MC68160B
0
1
t 242
1
0
t 261/ t 262
0
–175mV
t 241
0
+175mV
Symbol
90%
10%
t 240
t 241
t 242
t 243
t 244
Symbol
t 243
1
t 261
t 262
t 266
t 267
0
–
Min
200
1.0
–
–
–
10%
1
1
90%
t 241
99.5–100.5
Min
49.5–50.5
0V
318
30
–
–
–
Typ
–
–
–
1
t 244
70%
Max
1315
100
450
18
–
Max
100
5.0
–
–
–
Unit
Unit
mV
ns
ns
ns
ns
ns
ns
ns
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