Everest CORE - Product Manual |
Application Guide
INGENIA | 08/01/2019
49
Design Notes
•
The circuit does not include a termination resistor the Clock output, although it might be advisable if the
absolute encoder is connected along a very long cable, or a harsh electromagnetic environment.
•
C2, C3, C5 and C6, in combination with R1, R2, R6 and R8, perform a protective function of the transceiver in
front of spikes or ESD, and at the same time increases immunity to common mode noise. Capacitors could
be increased up to 220 pF to reinforce this effects even more if required.
• If a stronger ESD protection is required, a TVS diodes with capacitance <100 pF are acceptable, whenever C2,
C3, C5 and C6 values are kept as suggested.
•
The Data receiver uses a resistor voltage divider to set a 2.5 V bias. This would allow connecting this circuit
to a single-ended absolute encoder and still being able to read it properly. In this case, leave the negative
terminal of the differential pair unconnected.
•
R4 pulls-up the positive terminal for an extra robustness in front of a weak and noisy connection.
•
C1 and C4 are decoupling capacitors for U1 and U2.
Bill of materials
Designator
Part Number
Manufacturer
Package Value / Description
C1, C4
GRM155R71C104KA88D
Murata
0402
Ceramic capacitor, 100 nF, 16 V, X7R
C2, C3, C5,
C6
CC0402JRNPO9BN101
Yageo
0402
Ceramic capacitor, 100 pF, 50 V, NP0
R1, R2, R6,
R8
MC 0.063W 0603 1%
10R
Multicomp
0603
Thick film resistor, 10
Ω
, 1 %
tolerance, 1/16 W
R3
RMCF0402FT10K0
Stackpole
0402
Thick film resistor, 10 k
Ω
, 1 % tolerance,
1/16 W
R7
ERJ3EKF2200V
Panasonic
0603
Thick film resistor, 220
Ω
, 1 %
tolerance, 0.1 W
R4, R5, R9
RMCF0402FT2K00
Stackpole
0402
Thick film resistor, 2 k
Ω
, 1 %
tolerance, 1/16 W
U1, U2
SN65HVD75DGKR
Texas
Instruments
8-VSSOP RS485/422 half-duplex transceiver, 20
Mbps
7.2.6. LED Signalling
Everest CORE allows directly driving small LEDs for signalling up to 3 mA. This circuits would provide signalling for
Logic supply and Fault state of the Everest CORE.
