+5V Multiprotocol, Software-Selectable

Control Transceivers

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Detailed Description

The MXL1544/MAX3175 are four-driver/four-receiver

multiprotocol transceivers that operate from a single

+5V supply and the charge pump from the MXL1543.

The MXL1544/MAX3175, along with the MXL1543 and

MXL1344A, 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 MXL1544 or MAX3175

usually carries the control signals. The MXL1543 car-

ries the high-speed clock and data signals, and the

MXL1344A provides termination for the clock and data

signals.

The MXL1544/MAX3175 feature a 0.5µA no-cable

mode, true fail-safe operation, and thermal shutdown

circuitry. Thermal shutdown protects the drivers against

excessive power dissipation. When activated, the ther-

mal shutdown circuitry places the driver outputs into a

high-impedance state. The MAX3175 deglitching fea-

ture reduces errors in unterminated equipment.

The state of the mode-select pins M0, M1, and M2

determines which serial-interface protocol is selected

(Table 1). The state of the DCE/DTE input determines

whether the transceivers will be 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 disabled. When the DCE/DTE input is logic LOW,

driver T3 is disabled and receiver R1 is activated. The

INVERT pin state changes the DCE/DTE functionality

regarding T4 and R4 only. M0, M1, M2, INVERT, and

HIGH if left unconnected.

R

R

Figure 1. V.11 DC Test Circuit

DA

Figure 3. V.10/V.28 Driver Test Circuit

100pF

15pF

100pF

100

Ω

D

A

B

B

A

R

15pF

DA

R

Figure 2. V.11 AC Test Circuit

Figure 4. V.10/V.28 Receiver Test Circuit

Test Circuits