M2050 Datasheet, PDF (3/12 Pages) Integrated Circuit Systems – SAW PLL FOR 10GBE 64B/66B FEC

Integrated
Circuit
Systems, Inc.
M2050/51/52
SAW PLL FOR 10GBE 64B/66B FEC
Preliminary Information
DETAILED BLOCK DIAGRAM
M2050, 51, 52
R_LOOP C_LOOP
OP_IN
R_LOOP C_LOOP
nOP_IN OP_OUT
R_POST
R_POST
C_POST
C_POST
nOP_OUT nVC VC
External
Loop Filter
Components
NBW
LOL
Hitless Switch Option
Phase Buildout Option
DIF_REF0
nDIF_REF0
DIF_REF1
nDIF_REF1
REF_SEL
MUX
0
1
Rfec
Div
Phase
Detector ^RIN
R_IN
Loop Filter
Amplifier
Mfec Div
Mfin Divider
(1, 4, 5, 25)
Phase
Locked
Loop
(PLL)
SAW Delay Line
Phase
Shifter
VCSO
FEC_SEL1:0
FIN_SEL1:0
P_SEL2:0
Mfec/Rfec Divider
LUT
Mfin Divider
LUT
P Divider
LUT
Figure 3: Detailed Block Diagram
P Divider
(1, 4, 5, 25,
or TriState)
FOUT0
nFOUT0
FOUT1
nFOUT1
DIVIDER SELECTION TABLES
Mfin Divider Look-Up Tables (LUT)
Mfec and Rfec Divider Look-Up Tables (LUTs)
The FIN_SEL1:0 pins select the feedback divider value
(“Mfin”). Since the VCSO frequency is fixed, this allows
input reference selection. The look-up tables vary by
device variant.
The FEC_SEL pins select the Mfec/Rfec divider ratio.
The look-up tables vary by device variant. The Mfec
and Rfec values also establish phase detector
frequency. A lower phase detector frequency improves
jitter tolerance and lowers loop bandwidth.
M2050/51/52: Mfin Value LUT
FIN_SEL1:0
Mfin
Value
Sample Input Reference Freq. (MHz) Options
For M2050¹, M2051 & M2052²
0 0 25
25.00
01 5
10 4
11 1
125.00
156.25
625.00
Table 3: M2050/51/52: Mfin Value LUT
Note 1: For M2050 with Fvcso = 669.6429
Note 2: For M2051 and M2052 with Fvcso = 625.0000.
M2050: Map LUT (10GbE to LAN, 255/238 FEC, or 255/237 FEC)
FEC_SEL1:0
10
Mfec
Rfec
Description
Base Input
Rate (MHz)
Fvcso =
Base Output
Rate (MHz)
For M2050 with Fvcso = 644.5313 (10GbE to 10GbE LAN rate):
0 0 33 32 10GbE to 10GbE LAN
625.0000 644.5313
0 1 33 33 10GbE LAN repeater
644.5313 644.5313
For M2050 with Fvcso = 669.6429 (10GbE to 10GbE 255/238 FEC rate):
1 0 15 14 10GbE to 10GbE 255/238 FEC 625.0000 669.6429
1 1 15 15 10GbE 255/238 FEC repeater
669.6429 669.6429
For M2050 with Fvcso = 690.5692 (10GbE LAN to 10GbE LAN 255/238 FEC):
10GbE LAN to 10GbE LAN
1 0 15 14 255/238 FEC
644.5313 690.5692
1 1 15 15 10GbE LAN 255/238 FEC repeater 690.5692 690.5692
For M2050 with Fvcso = 693.4830 (10GbE LAN to 10GbE LAN 255/237 FEC):
10GbE LAN to 10GbE LAN
0 0 85 79 255/237 FEC
644.5313 693.4830
0 1 85 85 10GbE LAN 255/237 FEC repeater 693.4830 693.4830
Table 4: M2050: Map LUT (10GbE to LAN, 255/238 FEC, or 255/237 FEC)
M2050/51/52 Datasheet Rev 1.0
3 of 12
Revised 23Jun2005
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