DS3181 Maxim Integrated Products, DS3181 Datasheet - Page 165

• Manufacturer Part Number: DS3181
• Description: Network Controller & Processor ICs DS3-E3 ATM-Packet PH Y with Built-in Line
• Manufacturer: Maxim Integrated Products

Specifications of DS3181

• Product: Framer
• Number Of Transceivers: 1
• Data Rate: 44.736 Mbps
• Supply Voltage (max): 3.465 V
• Supply Voltage (min): 3.135 V
• Supply Current (max): 280 mA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Package / Case: TEBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

boundary is found, the multiframe frame boundary can be found. The multiframe boundary is found by identifying
the multiframe alignment bits M
framer is an off-line framer that only updates the data path frame counters when either an out of frame (OOF) or an
out of multiframe (OOMF) condition is present. The use of an off-line framer reduces the average time required to
reframe, and reduces data loss caused by burst error. The DS3 framer has a Maximum Average Reframe Time
(MART) of approximately 1.0ms.
Figure 10-40. DS3 Frame Format
The sub-frame framer continually searches four adjacent bit positions for a sub-frame boundary. A sub-frame
alignment bit (F-bit) checker checks each bit position. All four-bit positions must fail before any other bit positions
are checked for a sub-frame boundary. There are 170 possible bit positions that must be checked, and four
positions are checked simultaneously. Therefore up to 43 checks may be needed to identify the sub-frame
boundary. The sub-frame framer enables the multiframe frame once it has identified a sub-frame boundary. See
Figure 10-41
M
M
M
X
X
P
P
1
2
1
2
1
2
3
for the sub-frame framer state diagram.
F
F
F
F
F
F
F
11
21
31
41
51
61
71
C
C
C
C
C
C
C
11
21
31
41
51
61
71
1
, M
2
, and M
F
F
F
F
F
F
F
12
22
32
42
52
62
72
3
, which have a value of zero, one, and zero respectively. The DS3
680 Bits
C
C
C
C
C
C
C
12
22
32
42
52
62
72
165
F
F
F
F
F
F
F
13
23
33
43
53
63
73
C
C
C
C
C
C
C
13
23
33
43
53
63
73
F
F
F
F
F
F
F
14
24
34
44
54
64
74
7 Sub-
Frames