28
ispClock5400D Evaluation Board
Lattice Semiconductor
User’s Guide
HCSL
HCSL termination involves a bias network to ground at the driver and no termination at the end of the T-Line.
Figure 32 shows the drivers biased through series resistors R16 and R17 (value of 33 ohms) combined with resis-
tors R19 and R20 (value of 50 ohms). R19 and R20 also provide T-Line source termination. The receiving end of
the T-Line does not require any termination. The sense resistors R28 and R29 (value 950 ohms) are not low
enough to serve as termination loads but, provide a way to view the waveforms on the scope. The scope input
impedance combined with R28 and R29 result in a 20:1 divider of the waveforms at the end of the T-Line.
Figure 32. Bank 0 HCSL with On-Board Termination
ispClock5406D Standard Evaluation Board
ispClock
R16
R17
33
33
R23
0
R24
0
R28
R29
R30
0
R31
0
BANK_0P
J3
J4
BANK_0N
50
5pF
50
5pF
50 ohms / 64.3 mm
m
c
1
9
/
s
m
h
o
0
5
m
m
3
.
4
6
/
s
m
h
o
0
5
SMA to BNC Cable
SMA to BNC Cable
On Board T-Line
On Board T-Line
HCSL
Buffers
50 ohms / 91 cm
950
950
R19
50
R20
50
Scope
Power Supply Connections
The evaluation board is powered by a 12V to 5V power supply capable of providing one ampere or more. The
board can be powered either by a wall adapter with a 2.5mm coaxial power plug at J13 or from a bench supply with
banana plugs at J11 and J12. Once onboard, the supply is regulated (U2) to provide the 3.3V supply needed for
VCCD, VCCA, and VCCJ.
A second adjustable regulator (U3) provides the VCCO for banks 3 and 5 and it is programmable using the on-
board resistors and three of the DIP switches of SW1. To bypass the on-board regulators, zero ohm resistors R106
and R116 can be removed from the board to allow external supplies to power the ispClock5406D.
Troubleshooting
PAC-Designer 5.2: The ispClock5406D PLL Control dialog box of the ispClock5406D I
2
C Utility
(ispClock_5406_I2C_Utility.exe) appears corrupted and the background color obscures the schematic
view.
To correct the display:
1.
Exit the ispClock5406D I
2
C Utility.
2.
From Windows, browse to the
\PAC-Designer52\Macro
folder of the PAC-Designer installation directory.
3.
Locate the following files:
ispClock_5406_I2C_OutGroup_BI_Sch.emf
ispClock_5406_I2C_OutGroup_LI_Sch.emf
ispClock_5406_I2C_OutGroup_UI_Sch.emf
ispClock_5406_I2C_OutGroup_Sch.emf
ispClock_5406_I2C_PLL_Sch.emf
4.
Rename each file so they appear as:
ispClock_5400_I2C_OutGroup_BI_Sch.emf
ispClock_5400_I2C_OutGroup_LI_Sch.emf
ispClock_5400_I2C_OutGroup_UI_Sch.emf