Lattice Semiconductor ispClock5400D User Manual page 27

Lattice Semiconductor
Figure 29. Bank 0 SSTL15/SSTL18 with On Board Termination
ispClock
SSTL
Buffers
SSTL25
Figure 30 shows the only difference from SSLT15/SSTL18 and SSTL25 is the source termination R16 and R17
increases from 20 ohms to 25 ohms. The remainder of the circuit is the same as SSTL15/SSTL18, discussed
above.
Figure 30. Bank 0 SSTL25 with On-Board Termination
ispClock
SSTL
Buffers
eHSTL/HSTL
For eHSTL and HSTL the source termination resistance R16 and R17 drops to zero ohms as shown in Figure 31.
The remainder of the termination and sensing circuitry is the same as for SSTL.
Figure 31. Bank 0 eHSTL/HSTL with On Board Termination
ispClock
HSTL
Buffers
VCCO
R33
100
On Board T-Line
R16
50 ohms / 64.3 mm
20
VCCO
R32
100
On Board T-Line
R17
50 ohms / 64.3 mm
20
ispClock5406D Standard Evaluation Board
VCCO
R33
100
On Board T-Line
R16
50 ohms / 64.3 mm
25
VCCO
R32
100
On Board T-Line
R17
50 ohms / 64.3 mm
25
ispClock5406D Standard Evaluation Board
VCCO
R33
100
On Board T-Line
R16
50 ohms / 64.3 mm
0
VCCO
R32
100
On Board T-Line
R17
50 ohms / 64.3 mm
0
ispClock5406D Standard Evaluation Board
ispClock5400D Evaluation Board
BANK_0P
J3
R28
R23 R30
71.5 0
R25
18.7
45.3
R27
0
R26
R29
45.3
R24 R31
71.5 0
18.7
J4
BANK_0N
BANK_0P
J3
R28
R23 R30
71.5 0
R25 18.7
45.3
R27
0
R26
R29
45.3
R24 R31
71.5 0
18.7
J4
BANK_0N
BANK_0P
J3
R28
R23 R30
71.5 0
R25
18.7
45.3
R27
0
R26
R29
45.3
R24 R31
71.5 0
18.7
J4
BANK_0N
27
User's Guide
Scope
50
SMA to BNC Cable
50 ohms / 91 cm
5pF
50
SMA to BNC Cable
50 ohms / 91 cm
5pF
Scope
50
SMA to BNC Cable
50 ohms / 91 cm
5pF
50
SMA to BNC Cable
50 ohms / 91 cm
5pF
Scope
50
SMA to BNC Cable
50 ohms / 91 cm
5pF
50
SMA to BNC Cable
50 ohms / 91 cm
5pF