THVD1500 Datasheet, PDF (19/29 Pages) Texas Instruments – 300 kbps RS-485 Transceivers With 8-kV IEC ESD Protection

THVD1500
www.ti.com
SLLSEY4 – JULY 2017
Typical Application (continued)
9.2.2 Detailed Design Procedure
In order to protect bus nodes against high-energy transients, the implementation of external transient protection
devices is necessary. Figure 22 suggest a protection circuit against 1 kV surge (IEC 61000-4-5) transients.
Table 3 shows the associated Bill of Materials.
100nF
10k
R
RxD
MCU/
RE
UART
DE
DIR
D
TxD
10k
5V
100nF
V_CC
A
B
GND
R1
TVS
R2
Copyright © 2017, Texas Instruments Incorporated
Figure 22. Transient Protection Against ESD, EFT, and Surge Transients for Half-Duplex Devices
DEVICE
XCVR
R1
R2
TVS
FUNCTION
RS-485 transceiver
Table 3. Bill of Materials
ORDER NUMBER
THVD1500
10-Ω, pulse-proof thick-film resistor
CRCW0603010RJNEAHP
Bidirectional 400-W transient suppressor
CDSOT23-SM712
9.2.3 Application Curves
MANUFACTURER
TI
Vishay
Bourns
Time ± 2 Ps/div
Data Rate = 300 Kbps
Figure 23. TBD
10 Power Supply Recommendations
To ensure reliable operation at all data rates and supply voltages, each supply should be decoupled with a 100
nF ceramic capacitor located as close to the supply pins as possible. This helps to reduce supply voltage ripple
present on the outputs of switched-mode power supplies and also helps to compensate for the resistance and
inductance of the PCB power planes.
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