Detailed Description
The MXL1543 is a three-driver/three-receiver, multipro-
tocol transceiver that operates from a single +5V sup-
ply. The MXL1543, along with the MXL1544/MAX3175
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), and V.35 protocols. The MXL1543 transceivers
carry the high-speed clock and data signals, while the
MXL1544/MAX3175 transceivers carry serial interface
control signaling. The MXL1543 can be terminated by
the MXL1344A software-selectable resistor termination
network or by a discrete termination network. The
MXL1543 features 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 thermal shutdown cir-
cuitry places the driver outputs into a high-impedance
state.
Mode Selection
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 transceiver will be configured as a DTE or
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
MXL1543
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceivers
_______________________________________________________________________________________ 9
Pin Description
PIN NAME FUNCTION
1 C1- Capacitor C1 Negative Terminal. Connect a 1µF ceramic capacitor between C1+ and C1-.
2 C1+ Capacitor C1 Positive Terminal. Connect a 1µF ceramic capacitor between C1+ and C1-.
3V
DD
Generated Positive Supply. Connect a 4.7µF ceramic capacitor to ground.
4V
CC
+5V Supply Voltage (±5%). Decouple with a 1µF capacitor to ground.
5 T1IN Transmitter 1 TTL-Compatible Input
6 T2IN Transmitter 2 TTL-Compatible Input
7 T3IN Transmitter 3 TTL-Compatible Input
8 R1OUT Receiver 1 CMOS Output
9 R2OUT Receiver 2 CMOS Output
10 R3OUT Receiver 3 CMOS Output
11 M0 Mode-Select Pin with Internal Pullup to V
CC
12 M1 Mode-Select Pin with Internal Pullup to V
CC
13 M2 Mode-Select Pin with Internal Pullup to V
CC
14 DCE/DTE DCE/DTE Mode-Select Pin with Internal Pullup to V
CC
15 R3INB Noninverting Receiver Input
16 R3INA Inverting Receiver Input
17 R2INB Noninverting Receiver Input
18 R2INA Inverting Receiver Input
19
Inverting Transmitter Output/Inverting Receiver Input
21 T2OUTB Noninverting Transmitter Output
22 T2OUTA Inverting Transmitter Output
23 T1OUTB Noninverting Transmitter Output
24 T1OUTA Inverting Transmitter Output
25 GND Ground
26 V
EE
Generated Negative Supply. Connect a 4.7µF ceramic capacitor to ground.
27 C2- Capacitor C2 Negative Terminal. Connect a 1µF ceramic capacitor between C2+ and C2-.
28 C2+ Capacitor C2 Positive Terminal. Connect a 1µF ceramic capacitor between C2+ and C2-.
