Detailed Description
The MXL1344A contains six software-selectable multi-
protocol cable termination networks (Figure 3). Each
network is capable of terminating V.11 (RS-422, RS-
530, RS-530A, RS-449, V.36 and X.21) with a 100Ω dif-
ferential load, V.35 with a T-network load, or V.28
(RS-232) and V.10 (RS-423) with an open-circuit load
for use with transceivers having on-chip termination.
The termination protocol can be selected by the serial
interface cable wiring or by software control. The
MXL1344A replaces discrete resistor termination net-
works and expensive relays required for multiprotocol
termination, saving space and cost.
The MXL1344A terminator is designed to form a com-
plete +5V cable- or software-selectable multiprotocol
DTE/DCE interface port when used with the MXL1543
and MXL1544/MAX3175 transceivers. The MXL1344A
terminator can use the V
EE
power generated by the
MXL1543 charge pump, simplifying system design. The
MXL1344A, MXL1543, and MXL1544/MAX3175 are pin-
for-pin compatible with the LTC1344A, LTC1543, and
LTC1544, but for proper operation, the entire Maxim
MXL1344A
+5V Multiprotocol, Software-Selectable
Cable Terminator
4 _______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1 M0 Mode-Select Pin (Table 1)
2V
EE
Negative Supply Voltage (typically connected to V
EE
of MXL1543*). Bypass to GND with a 0.1µF
capacitor.
3 R1C Load 1, Center Tap
4 R1B Load 1, Node B
5 R1A Load 1, Node A
6 R2A Load 2, Node A
7 R2B Load 2, Node B
8 R2C Load 2, Center Tap
9 R3A Load 3, Node A
10 R3B Load 3, Node B
11 R3C Load 3, Center Tap
12, 13 GND Ground
14 V
CC
+5V Supply Voltage. Bypass to GND with a 0.1µF capacitor.
15 R4B Load 4, Node B
16 R4A Load 4, Node A
17 R5B Load 5, Node B
18 R5A Load 5, Node A
19 R6A Load 6, Node A
20 R6B Load 6, Node B
21 LATCH
Latch Signal Input. When LATCH is LOW, the input latches are transparent. When LATCH is high, the
data at the mode-select inputs are latched.
22 DCE/ DTE Logic Level HIGH selects DCE interface, (Table 1)
23 M2 Mode-Select Pin (Table 1)
24 M1 Mode-Select Pin (Table 1)
*V
EE
is typically supplied by the charge pump of the MXL1543. The V
EE
input level varies with the mode of chipset operation
as follows:
V.35/V.28 Modes: -6.50V ≤ V
EE
≤ -5.45V, in typical operation V
EE
= -5.80V
V.10/V.11 Modes: -4.60V ≤ V
EE
≤ -3.80V, in typical operation V
EE
= -4.20V
