UM-B-041
SmartBond Production Line Tool
User Manual
Revision 4.8
02-Nov-2022
CFR0012
138 of 170
© 2022 Renesas Electronics
Appendix I Improving Cabling Between PLT and DUTs
The following recommendations can be used to improve the connections between PLT and DUTs:
●
Keep the lengths of the cables as short as possible
●
When possible, use twisted pair cables instead of separate cables for:
○
GND/VBAT
○
GND/TxD
○
GND/RxD
●
Use ferrite beads for noise reduction in cables
Figure 123: Example of Twisted Pair Cable with 4 Pairs and Ferrite
●
Connect pull-down resistors at the end of the PLT TX signal lines. Use a 4.7 k
resistor at PLT
DUT Connector Pin 7 (DUT TX) with the other end connected to ground. In total 16 resistors
must be mounted, one for each PLT DUT connector
●
Connect a pull-down resistor as close as possible to the UART RX signal connector on the DUT.
The value should be approximately 4.7 k
. Connect the other end of the resistor to ground
●
Use gold plated contacts in the connections between the PLT and the DUTs
●
Use extra drivers in the UART lines
●
Use series resistors of approximately 100
in the UART lines, one mounted at the beginning
and one at the end of the signal lines
Note:
Start with the simple solutions first by testing them one-by-one for stability.
and
show examples of some of the above proposals.
Production Line Tool
1
2
3
4
5
6
7
8
9
10
XTAL Calibration
Pulse
not used
GND
VPP
RST
VBAT
not used
not used
DUT TX
DUT RX
(pinning 100 mil)
VBAT
UART TX
UART RX
VPP
GND
4
k7
4
k7
R
1
R
2
DUT
‘Twisted Pair’ cables
Figure 124: Location of Pull-Down Resistors