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3.8
Reset Operations
U8
To RST of
U12 and U13
From DIT
+3.3V
U7
SW4
N.O.
4
Schematic, PCB Layout, and Bill of Materials
4.1
Schematic
Schematic, PCB Layout, and Bill of Materials
The PCM4202EVM includes two reset switches, SW2 and SW4. Both are momentary contact
pushbutton switches that are normally open. SW2 provides the manual reset for the PCM4202
(U1), while switch SW4 provides the manual reset for the two DIT4192 transmitters (U12 and U13).
The PCM4202 may be reset at any time my momentarily pressing and then releasing switch SW2.
This generates a reset pulse and initiates a reset sequence for the device.
For the DIT reset function, the output of the reset circuit is connected to the RST pins of DIT4192
transmitters (U12 and U13). The transmitters may be reset only when the DIT switch of SW3 is set
LO by momentarily pressing and then releasing switch SW4. If the DIT switch is set HI, the output
of the AND gate in the reset circuit is forced low, which will force both transmitters into power-down
mode. The transmitter reset circuit is shown in
Figure 3
.
Figure 3. DIT (Transmitter) Reset Circuitry
This section provides the electrical schematic and physical layout information for the
PCM4202EVM. The bill of materials is included as a component reference.
NOTE
Board layouts are not to scale. These figures are intended to show how the board is
laid out; they are not intended to be used for manufacturing PCM4202EVM PCBs.
The electrical schematic for the PCM4202EVM is shown in
Figure 4
. The components shown in the
schematic are listed in
Table 11
for reference.
PCM4202EVM User's Guide
SBAU103–August 2004
13
