Figure 4. V.10/V.28 Receiver Test Circuit
Test Circuits
+5V Multiprotocol, Software-Selectable
Clock Transceiver
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Detailed Description
The MAX13172E is a four-driver/four-receiver, multipro-
tocol transceiver that operates from a single +5V sup-
ply. The charge pump operates from the MAX13170E.
The MAX13172E along with the MAX13170E and
MAX13174E, form a complete software-selectable
DTE or DCE interface port that supports the V.28
(RS-232), V.10/V.11 (RS-449/V.36, EIA-530, EIA-530A,
X.21, RS-423), and V.35 protocols. The MAX13172E
usually carries the control signals. The MAX13170E car-
ries the high-speed clock and data signals, and the
MAX13174E provides termination for the clock and data
signals.
The MAX13172E features an ultra-low supply current
no-cable mode, fail-safe operation, and thermal-shut-
down circuitry. Thermal shutdown protects the transmit-
ter and receiver outputs against excessive power dissi-
pation. When activated, the thermal-shutdown circuitry
places the driver outputs into a high-impedance state.
The state of the mode-select inputs M0, M1, and M2
determines which serial-interface protocol is selected
(Table 1). The state of the DCE/DTE input determines
whether the transceivers are configured as a DTE serial
port or a DCE serial port. When the DCE/DTE input is
logic-high, driver T3 is activated and receiver R1 is dis-
abled. When the DCE/DTE input is logic-low, driver T3
disabled and receiver R1 is activated. The INVERT
input state changes the DCE/DTE functionality regard-
ing T4 and R4 only. M0, M1, M2, INVERT, and
DCE/DTE are internally pulled up to V
CC
to ensure
logic-high if left unconnected.
