SM844256 Datasheet, PDF (3/8 Pages) Micrel Semiconductor – 10 Gigabit Ethernet and SONET, 6 Output, Ultra-Low Jitter LVDS Frequency Synthesizer

Micrel, Inc.
SM844256
Pin Description
Pin Number
1, 2
3, 4
5, 6
7, 8
Pin Name
V_DDO
/Q2, Q2
/Q1, Q1
/Q0, Q0
9
PLL_BYPASS
10
11
12
13
14
15
16, 17
18
19, 20
21, 22
23, 24
V_DDA
V_DD
FB_SEL
XTAL_IN
XTAL_OUT
N_SEL0
GND
N_SEL1
/Q5, Q5
/Q4, Q4
/Q3, Q3
Pin Type
PWR
O, (DIF)
O, (DIF)
O, (DIF)
I, (SE)
PWR
PWR
I, (SE)
I, (SE)
O, (SE)
I, (SE)
PWR
I, (SE)
O, (DIF)
O, (DIF)
O, (DIF)
Pin Level
LVDS
LVDS
LVDS
LVCMOS
LVCMOS
12pF crystal
12pF crystal
LVCMOS
LVCMOS
LVDS
LVDS
LVDS
Pin Function
2.5V or 3.3V Power Supply
Differential Clock Output
Differential Clock Output
Differential Clock Output
Pull-Up 45k, Single-Ended Input Select Pin.
Logic (0) = PLL Output
Logic (1) = Xtal Reference
Analog 3.3V or 2.5V Power Supply
3.3V or 2.5V Power Supply
Pull-Down 45k, Single-Ended Input Select Pin
Crystal Reference Input, no load caps needed.
Crystal Reference Output, no load caps needed.
Pull-Up 45k, Single-Ended Input Select Pin
Ground
Pull-Up 45k, Single-Ended Input Select Pin
Differential Clock Output
Differential Clock Output
Differential Clock Output
Input and Output Frequency Table
XTAL (MHz)
24
24
24
24
25
25
25
FB_SEL
0
0
0
0
0
0
0
N_SEL1
0
0
1
1
0
0
1
25
0
1
18.75
18.75
18.75
18.75
19.44
19.44
19.44
19.44
19.53125
19.53125
19.53125
19.53125
1
0
1
0
1
1
1
1
1
0
1
0
1
1
1
1
1
0
1
0
1
1
1
1
N_SEL0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Outputs (MHz)
600
300
150
120
625
312.50
156.25
125
600
300
150
75
622.08
311.04
155.52
77.76
625
312.5
156.25
78.125
Application
-
-
SAS/SATA
-
10 Gigabit Ethernet
10 Gigabit Ethernet
10 Gigabit Ethernet
Gigabit Ethernet/Infiniband/PCI/PCI-
E/PCI-X
-
-
SAS/SATA
SAS/SATA
10 Gigabit Ethernet/SONET
SONET
SONET
SONET
10 Gigabit Ethernet
10 Gigabit Ethernet
10 Gigabit Ethernet
10 Gigabit Ethernet
July 2010
3
M9999-072110-B