Texas Instruments TRS3221RGTEVM, Руководство пользователя

Страница: 4 / 13

3 Schematic and Layout
The TRS3221RGTEVM has simple connections to all necessary pins of the TRS3221RGT transceiver device,
and jumpers where necessary to provide flexibility for device. The TRS3221RGTEVM provides test points for all
RS-232 (TX1, RX1) and logic (TX2, RX2) communication lines. Additionally test points of GND, VCC, and
charge pump output voltage are available for probing and evaluation.
3.1 Schematic
The schematic is shown in Figure 3-1 . The function of each jumper and test point is listed in Table 3-1 .
GND
GND
VCC
VCC
GND
16V
0.1uF
C2
16V
0.1uF
C4
16V
0.1uF
C1
0
R5
0
R6
0
R7
10.0k
R1
TX1
TX1
RX1
RX1
RX2
RX2
TX2
TX2
V-
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
J2
1uF
C6
1
2
3
4
5
6
7
8
9
1
1
1
0
J1
618009231121
INV
10.0k
R2
ON
OFF INV
ON
OFF
VCC
12
EN
14
FORCEOFF
13
INVALID
7
C1+
16
C1-
1
C2+
2
C2-
3
FORCEON
9
RIN
5
ROUT
6
Thermal_Pad
17
TIN
8
TOUT
10
V+
15
V-
4
GND
11
TRS3221EIRGTR
U0 VCC
16V
0.1uF
C3
10V
0.1uF
C5
V+
GND
VCC
10.0k
R3
10.0k
R4
EN
ON
OFF
EN
EN
10.0k
R8
GND
Figure 3-1. TRS3221RGTEVM Schematic
Table 3-1. Jumpers and Test Points
Connection Type Description
J1 9-pin connector Female DB9 connector to
connect to PC
J2 16-pin jumper Used for supply and TTL signal
V+ Test point Charge pump positive output
V- Test point Charge pump negative output
Power and logic signal go through the J1 connector. Table 3-2 lists each pin’s connection.
Table 3-2. J1 pin connection
Connection Type Description
1 NC Not connected
2 Output RX1, pin 10 of transceiver
3 Input TX1, pin 5 of transceiver
4 Loopback Connected to pin 6
5 GND Ground
6 Loopback Connected to pin 4
7 NC Not connected
8 NC Not connected
9 NC Not connected
The female DB9 port ( Figure 3-2 ) provides access to the TRS3221RGT device through a standard RS-232
pinout. The TRS3221RGT female port is DCE to mate with a computer male DTE port. The pin names are
counterintuitive on the DCE side. For example, the RX pin on EVM is connected to a driver and TX connects to a
receiver. The reason pins 4 and 6 are shorted together by a 0 Ω resistor is to loopback the unused handshaking
lines.
Schematic and Layout www.ti.com
4 TRS3221 EVM User's Guide SLLU328 – DECEMBER 2020
Submit Document Feedback
Copyright © 2020 Texas Instruments Incorporated