BCM5208KPF Broadcom, BCM5208KPF Datasheet - Page 11

• Manufacturer Part Number: BCM5208KPF
• Manufacturer: Broadcom

Specifications of BCM5208KPF

• Number Of Receivers: 4
• Data Rate: 10/100Mbps
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 3.14V
• Mounting: Surface Mount
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Lead Free Status / RoHS Status: Not Compliant

November 3, 1999
DIGITAL CLOCK RECOVERY/GENERATOR
The all-digital clock recovery and generator block creates all internal transmit and receive clocks. The transmit clocks are
locked to the 25 MHz clock input while the receive clocks are locked to the incoming data streams. Clock recovery circuits
optimized to MLT3, NRZI, and Manchester encoding schemes are included for use with each of the three different operating
modes. The input data streams are sampled by the recovered clock from each port and fed synchronously to the respective
digital adaptive equalizer.
BASELINE WANDER CORRECTION
A 100BASE-TX data stream is not always DC balanced. Because the receive signal must pass through a transformer, the
DC offset of the differential receive input can wander. This effect, known as baseline wander, can greatly reduce the noise
immunity of the receiver. The BCM5208 automatically compensates for baseline wander by removing the DC offset from
the input signal, and thereby significantly reduces the chance of a receive symbol error. The baseline wander correction
circuit is not required, and therefore bypassed, in 10BASE-T and 100BASE-FX operating modes.
Document 5208-DS03-R¥¥¥¥¥
NAME
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
I
J
K
T
R
H
4B CODE
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
0000*
0101*
0101*
0000*
0000*
1000
5B CODE
11110
01001
10100
10101
01010
01011
01110
01111
10010
10011
10110
10111
11010
11011
11100
11101
11111
11000
10001
01101
00111
00100
Table 1: 4B5B Encoding
B r o a d c o m C o r p o r a t i o n
MEANING
Data 0
Data 1
Data 2
Data 3
Data 4
Data 5
Data 6
Data 7
Data 8
Data 9
Data A
Data B
Data C
Data D
Data E
Data F
Idle
Start-of-Stream Delimiter, Part 1
Start-of-Stream Delimiter, Part 2
End-of-Stream Delimiter, Part 1
End-of-Stream Delimiter, Part 2
Transmit Error (used to force signalling errors)
n BCM5208
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