mode, for devices like the THVD2452VDR, the VIO pin can be shorted to VCC by shorting the header pins of J7,
so that the digital circuits are properly powered.
Table 2-1. Single Supply Operation Jumper Configurations
Component Name Comment
J7 Shorted for single supply operation
J1 VIO supply: leave open
J2 VCC power terminal
Apply VCC through the J2 terminal to power the EVM. With the board oriented with J6 on the top left, as shown
in Figure 2-1, the signals are, from right to left, EARTH, GND, and VCC. The EARTH and GND signal distinction
is used to help the end user to determine operational qualities with respect to ground potential differences. Install
a resistor on pad R16 for testing methods on reducing ground loop current. Check the data sheet for proper
powering considerations as supply recommendations can range from 3.3 V, 5 V, or 3.3 V to 5 V.
Providing power to the EVM is similar to the single supply option described in this section. Jumpers J1 and J2
have the same pin orientation from left to right: EARTH pin, GND pin, and voltage supply pin. Attach the VIO
power source to J1 and VCC power source to J2.
2.1.2 Dual Supply Operation
The THVD24X2V family of transceivers in the D (SOIC) package from TI can have an additional logic supply pin,
VIO. In dual supply operation, the digital circuit supply (which supplies the R, D, /RE, and DE pins) can be held
at a low voltage. This voltage typically ranges from 1.65 V to 5 V to allow interfacing with a RS-485 transceiver to
digital systems using 1.8 V logic. For dual supply operation, J7 is left open.
Table 2-2. Dual Supply Operation Jumper Configurations
Component Name Comment
J7 Leave open for dual supply operation
J1 VIO power input
J2 VCC power input
2.2 Operating the THVD24X2VEVM in Default Setup
Out-of-the-box the EVM, when powered, can operate the THVD2452V as a full duplex RS-485 transceiver. The
device pins are separated into four distinct groups: single-ended communication pins, differential communication
pins, power pins, and control pins. The preceding section Section 2.1 discusses the power pins in depth, the
other three types of pins are covered in this section.
The single-ended communication pins are connected directly through the respective jumpers to a single ended
bus. These pins are the “R” and “D” pins and represent RX and TX single-ended data, respectively. R is
referenced to J6 and D is reference to J16. J6 and J16 are the signal connection points for the EVM.
The EVM board supports two control signals: the enable pins and a slew rate control pin. The enable pins
include an active high Driver Enable (DE) pin and an active low Receiver Enable (/RE) pin. These pins are
accessed through jumpers J11 and J12, respectively. The Slew Rate Limiting pin (SLR) is a binary input that can
implement slew rate limiting to reduce emissions from the device at the cost of lower data rates. The SLR pin is
accessed through jumper J20.
The final group of signals, differential bus pins, are pins A, B, Y, and Z. The A and B pins are differential receiver
pins that are connected to terminal block J10. As is shown in Figure 2-1, with the board oriented to have J6 at
the top-left corner, the 2nd and 3rd pins of J10 are A and B, respectively. Y and Z are the differential driver pins
that are connected to terminal block J13. Using the same orientation shown in Figure 2-1, the 2nd and 3rd pins
of J13 are differential driver pins Z and Y, respectively.
Most signal inputs are use 2x4 headers. Each jumper has a specific mapping that connects the I/O, GND, VIO,
and EARTH (when present).
www.ti.com Operating the EVM
SLLU368 – APRIL 2023
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THVD24X2VEVM User's Guide 5
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