Page 1
General Description
The MXL1543B is a three-driver/three-receiver multiprotocol transceiver that operates from a +5V single supply. The MXL1543B, along with the MXL1544/MAX3175
and the MXL1344A, form a complete software-selectable data terminal equipment (DTE) or data communication equipment (DCE) interface port that supports the
V.28 (RS-232), V.10/V.11 (RS-449/V.36, EIA-530, EIA530A, X.21), and V.35 protocols. The MXL1543B transceivers carry the high-speed clock and data signals
while the MXL1544/MAX3175 carry the control signals.
The MXL1543B can be terminated by the MXL1344A
software-selectable resistor termination network or by
discrete termination networks.
An internal charge pump and a proprietary low-dropout
transmitter output stage allow V.11- , V.28- , and V.35compliant operation from a +5V single supply. A nocable mode is entered when all mode pins (M0, M1,
and M2) are pulled high or left unconnected. In nocable mode, supply current decreases to 0.5µA and all
transmitter and receiver outputs are disabled (high
impedance). Short-circuit current limiting and thermal
shutdown circuitry protect the drivers against excessive
power dissipation.
Applications
Features
♦ MXL1543B, MXL1544/MAX3175, and MXL1344A
Chipset Is Pin Compatible with LTC1543,
LTC1544, and LTC1344A
♦ Supports RS-232, RS-449, EIA-530, EIA-530A,
V.35, V.36, and X.21
♦ Software-Selectable Cable Termination Using the
MXL1344A
♦ Complete DTE or DCE Port with MXL1544/
MAX3175, and MXL1344A
♦ +5V Single-Supply Operation
♦ 0.5µA No-Cable Mode
♦ TUV-Certified NET1/NET2 and TBR1/TBR2-
Compliant
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceivers
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3444; Rev 0; 10/04
PART TEMP RANGE PIN-PACKAGE
MXL1543BCAI 0° to +70°C 28 SSOP
Data Networking
CSU and DSU
Data Routers
PCI Cards
Telecommunications
Equipment
Typical Operating Circuit
D1D2
D3D4
R1
R2R3
MXL1543B
RXD RXC TXDTXC SCTE
D1D2
D3
R1
R2R3
MXL1544
MAX3175
CTS DSR RTSDTRDCD
RXC B
RXD A (104)
RXD B
SG (102)
SHIELD (101)
RTS A (105)
RTS B
DTR A (108)
DTR B
DCD A (107)
DCD B
DSR A (109)
CTS A (106)
DSR B
CTS B
LL A (141)
TXD B
SCTE A (113)
SCTE B
TXC A (114)
TXC B
TXD A (103)
DB-25 CONNECTOR
13
R4
LL
RXC A (115)
18 5 10 8 22 6 23 20 19 4 1 7 16 3 9 17 12 15 11 24 14 2
MXL1344A
Pin Configuration appears at end of data sheet.
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Page 2
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, SoftwareSelectable Clock/Data Transceivers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC= +5.0V, C1 = C2 = C4 = 1µF, C3 = C5 = 4.7µF, (Figure 10), TA = T
MIN
to T
MAX
. Typical values are at TA = +25°C, unless other-
wise noted.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
All Voltages Referenced to GND Unless Otherwise Noted.
Supply Voltages
V
CC
.......................................................................-0.3V to +6V
V
DD
....................................................................-0.3V to +7.3V
V
EE
.....................................................................+0.3V to -6.5V
V
DD
to V
EE
(Note 1)................................................................13V
Logic Input Voltages
M0, M1, M2, DCE/
DTE, T_IN ................................-0.3V to +6V
Logic Output Voltages
R_OUT....................................................-0.3V to (V
CC
+ 0.3V)
Transmitter Outputs
T_OUT_, T3OUT_/R1IN_.....................................-15V to +15V
Short-Circuit Duration............................................Continuous
Receiver Input
R_IN_T3OUT_/R1IN_ ..........................................-15V to +15V
R_IN A to R_IN B..............................-15V to 0V or 0V to +15V
Continuous Power Dissipation (T
A
= +70°C)
28-Pin SSOP (derate 9.5mW/°C above +70°C) ...........762mW
Operating Temperature Range
MXL1543BCAI .....................................................0°C to 70°C
Junction Temperature .......................................................150°C
Storage Temperature Range ...........................-65°C to +150°C
Lead Temperature (soldering, 10s) ...............................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
V
CC
Operating Range V
CC
V
RS-530, RS-530A, X.21, no load 13
RS-530, RS-530A, X.21, full load 100 130
V.35 mode, no load 20
V.35 mode, full load 126 170
V.28 mode, no load 20
V.28 mode, full load 40 75
mA
Supply Current
(DCE Mode)
(Digital Inputs = GND or
V
CC
)
(Transmitter Outputs Static)
I
CC
No-cable mode 0.5 10 µA
RS-530, RS-530A, X.21, full load 230
V.35 mode, full load 600
Internal Power Dissipation
(DCE Mode)
P
D
V.28 mode, full load 140
mW
Any mode (except no-cable mode), no load 6.4 6.8
V.28 mode, with load 6.4 6.8
Positive Charge-Pump
Output Voltage
V
DD
V.28, V.35 modes, with load, IDD = 10mA 6.4 6.8
V
V.28, V.35, no load
V.28 mode, full load
-5.4
V.35 mode, full load
-5.4
Negative Charge-Pump
Output Voltage
V
EE
RS-530, RS-530A, X.21, full load
-5.4
V
Supply Rise Time t
r
No-cable mode or power-up to turn on 500 µs
LOGIC INPUTS (M0, M1, M2, DCE/DTE, T1IN, T2IN, T3IN)
Input High Voltage V
IH
2.0
Input Low Voltage V
IL
0.8
V
T1IN, T2IN, T3IN ±10
M0, M1, M2, DCE/DTE = GND
-50 -30
Logic Input Current I
IN
M0, M1, M2, DCE/DTE = V
CC
±10
µA
Note 1: VDDand VEEabsolute difference cannot exceed 13V.
4.75 5.25
-100
-5.6
-5.6
-5.6
-5.6
Page 3
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceivers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +5.0V, C1 = C2 = C4 = 1µF, C3 = C5 = 4.7µF, (Figure 10), TA= T
MIN
to T
MAX
. Typical values are at TA = +25°C, unless oth-
erwise noted.)
PARAMETER
CONDITIONS
UNITS
LOGIC OUTPUTS (R1OUT, R2OUT, R3OUT)
Output High Voltage V
OH
I
SOURCE
= 4mA 3 4.5
Output Low Voltage V
OL
I
SINK
= 4mA 0.3 0.8
V
Output Short-Circuit Current I
SC
0 ≤ V
OUT
≤ V
CC
±50 mA
Output Pullup Current I
L
V
OUT
= 0, no-cable mode 70 µA
V.11 TRANSMITTER
Open-Circuit Differential Output
Voltage
V
ODO
Open circuit, R = 1.95kΩ (Figure 1) ±5V
R = 50Ω (Figure 1), TA = +25oC
0.67
✕
Loaded Differential Output
Voltage
V
ODL
R = 50Ω (Figure 1) ±2
V
Change in Magnitude of Output
Differential Voltage
∆V
OD
R = 50Ω (Figure 1) 0.2 V
Common-Mode Output Voltage V
OC
R = 50Ω (Figure 1) 3.0 V
Change in Magnitude of Output
Common-Mode Voltage
∆V
OC
R = 50Ω (Figure 1) 0.2 V
Short-Circuit Current I
SC
V
OUT
= GND 150 mA
Output Leakage Current I
Z
-0.25V ≤ V
OUT
≤ +0.25V, power-off or
no-cable mode
±1
µA
Rise or Fall Time t
r
,
t
f
(Figures 2, 6) 2 10 25 ns
Transmitter Input to Output
Delay
(Figures 2, 6) 40 80 ns
Data Skew
(Figures 2, 6) 2 12 ns
Output to Output Skew t
SKEW
(Figures 2, 6) 3 ns
V.11 RECEIVER
Differential Threshold Voltage V
TH
-7V ≤ VCM ≤ 7V
200 mV
Input Hysteresis ∆V
TH
-7V ≤ VCM ≤ 7V 15 40 mV
Receiver Input Current I
IN
-10V ≤ V
A, B
≤10V
mA
Receiver Input Resistance R
IN
-10V ≤ V
A, B
≤ 10V 15 30 kΩ
Rise or Fall Time tr, t
f
(Figures 2, 7) 15 ns
Receiver Input to Output Delay
(Figures 2, 7) 50 80 ns
Data Skew
(Figures 2, 7) 2 16 ns
V.35 TRANSMITTER
Open circuit (Figure 3) ±7
Differential Output Voltage V
OD
With load, -4V ≤ VCM ≤ 4V (Figure 3)
V
Output High Current I
OH
V
A,B
= 0 -13 -11 -9 mA
Output Low Current I
OL
V
A,B
= 0 9 11 13 mA
SYMBOL
MIN TYP MAX
0.5
V
✕
ODO
V
ODO
±100
t
t
PHL
PLH
,
It
- t
PHL
I
PLH
-200
±0.66
t
PHL,tPLH
|t
- t
PLH
|
PHL
±0.44 ±0.55 ±0.66
Page 4
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, SoftwareSelectable Clock/Data Transceivers
4 _______________________________________________________________________________________
PARAMETER
CONDITIONS
UNITS
Output Leakage Current I
Z
-0.25V ≤ V
OUT
≤ +0.25V, power-off or no-
cable mode
±1
µA
Rise or Fall Time tr, t
f
(Figures 3, 6) 5 ns
Transmitter Input to Output
Delay
,
(Figures 3, 6) 35 80 ns
Data Skew
(Figures 3, 6) 2 16 ns
Output-to-Output Skew t
SKEW
(Figures 3, 6) 4 ns
V.35 RECEIVER
Differential Input Voltage V
TH
-2V ≤ VCM ≤ 2V (Figure 3)
200 mV
Input Hysteresis ∆V
TH
-2V ≤ VCM ≤ 2V (Figure 3) 15 40 mV
Receiver Input Current I
IN
-10V ≤ VA,B ≤ 10V
mA
Receiver Input Resistance R
IN
-10V ≤ VA,B ≤ 10V 15 30 kΩ
Rise or Fall Time tr, t
f
(Figures 3, 7) 15 ns
Receiver Input to Output Delay
(Figures 3, 7) 50 80 ns
Data Skew
(Figures 3, 7) 2 16 ns
V.28 TRANSMITTER
Open circuit ±7
Output Voltage Swing (Figure 4)
V
O
RL = 3kΩ±5 ±6
V
Short-Circuit Current I
SC
mA
Output Leakage Current I
Z
-0.25V ≤ V
OUT
≤ +0.25V, power-off or no-
cable mode
±1
µA
Output Slew Rate SR RL = 3kΩ, CL = 2500pF (Figures 4, 8) 4 30
V/µs
Transmitter Input to Output
Delay
t
PHL
RL = 3kΩ, CL = 2500pF (Figures 4, 8) 1.5 2.5 µs
Transmitter Input to Output
Delay
t
PLH
RL = 3kΩ, CL = 2500pF (Figures 4, 8) 1.5 3 µs
V.28 RECEIVER
Input Threshold Low V
IL
0.8 1.2 V
Input Threshold High V
IH
1.2 2.0 V
Input Hysteresis V
HYST
0.3 V
Input Resistance R
IN
-15V ≤ VIN ≤ +15V 3 5 7 kΩ
Rise or Fall Time tr, t
f
(Figures 5, 9) 15 ns
Receiver Input to Output Delay t
PHL
(Figures 5, 9) 60 100 ns
Receiver Input to Output Delay t
PLH
(Figures 5, 9) 160 250 ns
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +5.0V, C1 = C2 = C4 = 1µF, C3 = C5 = 4.7µF, (Figure 10), TA= T
MIN
to T
MAX
. Typical values are at TA = +25°C, unless oth-
erwise noted.)
SYMBOL
t
t
PHL
PLH
|t
PHL–tPLH
|
MIN TYP MAX
±100
-200
t
, t
PHL
PLH
|t
PHL–tPLH
|
0.05
±0.66
±150
±100
Page 5
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceivers
_______________________________________________________________________________________ 5
160
0
0.1 100 1000
V.11 SUPPLY CURRENT
vs. DATA RATE
40
20
60
80
100
120
140
MXL1543B toc01
DATA RATE (kbps)
SUPPLY CURRENT (mA)
10110,000
DCE MODE, R = 50Ω, ALL TRANSMITTERS
OPERATING AT THE SPECIFIED DATA RATE
0
20
60
40
80
100
010050 150 200 250
V.28 SUPPLY CURRENT
vs. DATA RATE
MXL1543B toc02
DATA RATE (kbps)
SUPPLY CURRENT (mA)
DCE MODE ALL TRANSMITTERS
OPERATING AT THE SPECIFIED DATA RATE
R
L
= 3kΩ, CL = 2500pF
160
0
0.1 100 1000
V.35 SUPPLY CURRENT
vs. DATA RATE
40
20
60
80
100
120
140
MXL1543B toc03
DATA RATE (kbps)
SUPPLY CURRENT (mA)
100.1 10,000
DCE MODE, FULL LOAD, ALL TRANSMITTERS
OPERATING AT THE SPECIFIED DATA RATE
180
200
-5
-2
-3
-4
0
-1
4
3
2
1
5
010203040506070
V.11 DRIVER DIFFERENTIAL OUTPUT
VOLTAGE vs. TEMPERATURE
MXL1543B toc04
TEMPERATURE (°C)
DRIVER DIFFERENTIAL OUTPUT VOLTAGE (V)
DCE MODE, R = 50
Ω
V
OUT+
V
OUT-
8
V.28 OUTPUT VOLTAGE
vs. TEMPERATURE
MXL1543B toc05
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
0304010 20 50 60 70
10
4
6
0
2
-4
-2
-8
-6
-10
DCE MODE, RL = 3k
Ω
V
OUT+
V
OUT-
-0.66
-0.22
-0.44
0.22
0
0.44
0.66
0304010 20 50 60 70
OUTPUT VOLTAGE (V)
V.35 OUTPUT VOLTAGE
vs. TEMPERATURE
MXL1543B toc06
TEMPERATURE (°C)
DCE MODE, VCM = 0
FULL LOAD
V
OL
V
OH
520
540
530
560
550
570
580
590
600
-4 -2 -1-3 01234
V.35 DIFFERENTIAL OUTPUT VOLTAGE
vs. COMMON-MODE VOLTAGE
MXL1543B toc07
COMMON-MODE VOLTAGE (V)
DIFFERENTIAL OUTPUT VOLTAGE (mV)
|VOD|
-300
0
-100
-200
100
200
300
-10 -2-4-8 -6 0246810
V.11/V.35 RECEIVER INPUT CURRENT
vs. INPUT VOLTAGE
MXL1543B toc08
INPUT VOLTAGE (V)
RECEIVER INPUT CURRENT (
µ
A)
DCE MODE
-0.5
1.0
0.5
0
1.5
2.0
2.5
-10 -2-4-8 -6 0246810
V.28 RECEIVER INPUT CURRENT
vs. INPUT VOLTAGE
MXL1543B toc09
INPUT VOLTAGE (V)
RECEIVER INPUT CURRENT (mA)
DCE MODE
-2.0
-2.5
-1.5
-1.0
Typical Operating Characteristics
(VCC= +5.0V, C1 = C2 = C4 =1µF, C3 = C5 = 4.7µF, (Figure 10), TA= T
MIN
to T
MAX
, TA = +25°C, unless otherwise noted.)
Page 6
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, SoftwareSelectable Clock/Data Transceivers
6 _______________________________________________________________________________________
200ns/div
V.11 LOOPBACK OPERATION
T
IN
T
OUT/RIN
R
OUT
5V/div
5V/div
5V/div
MXL1543B toc10
R = 50
Ω
1µs/div
V.28 LOOPBACK OPERATION
T
IN
T
OUT/RIN
R
OUT
5V/div
5V/div
5V/div
MXL1543B toc11
CL = 2500pF
RL = 3k
Ω
V.11 TRANSMITTER PROPAGATION DELAY
vs. TEMPERATURE
MXL1543B toc14
0
10
30
20
60
70
50
40
80
PROPAGATION DELAY (ns)
0203010
40
50 60 70
TEMPERATURE (°C)
t
PLH
t
PHL
V.11 RECEIVER PROPAGATION DELAY
vs. TEMPERATURE
MXL1543B toc15
0
10
30
20
60
70
50
40
80
PROPAGATION DELAY (ns)
0203010
40
50 60 70
TEMPERATURE (°C)
t
PLH
t
PHL
V.35 TRANSMITTER PROPAGATION DELAY
vs. TEMPERATURE
MXL1543B toc16
0
10
30
20
60
70
50
40
80
PROPAGATION DELAY (ns)
0203010
40
50 60 70
TEMPERATURE (°C)
t
PLH
t
PHL
V.35 RECEIVER PROPAGATION DELAY
vs. TEMPERATURE
MXL1543B toc17
0
10
30
20
60
70
50
40
80
PROPAGATION DELAY (ns)
0203010
40
50 60 70
TEMPERATURE (°C)
90
100
t
PHL
t
PLH
200ns/div
V.35 LOOPBACK OPERATION
T
IN
T
OUT/RIN
R
OUT
1V/div
5V/div
5V/div
MXL1543B toc12
FULL LOAD
0
4
2
6
8
10
12
14
16
18
20
22
24
0 1000 2000 3000 4000 5000
V.28 SLEW RATE vs. C
LOAD
MXL1543B toc13
C
LOAD
(pF)
SLEW RATE (V/µs)
+SLEW
-SLEW
RL = 3k
Ω
1 TRANSMITTER SWITCHING AT 250kbps.
OTHER TRANSMITTERS SWITCHING AT 15kbps
Typical Operating Characteristics (continued)
(VCC= +5.0V, C1= C2 = C4 =1µF, C3 = C5 = 4.7µF (Figure 10), TA = +25°C, unless otherwise noted.)
Page 7
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceivers
_______________________________________________________________________________________ 7
V
OC
R
R
V
OD
Figure 1. V.11 DC Test Circuit
C
L
R
L
V
O
A
D
Figure 4. V.28 Driver Test Circuit
D
A
R
15pF
Figure 5. V.28 Receiver Test Circuit
100pF
15pF
100pF
100
Ω
R
B
A
B
A
D
Figure 2. V.11 AC Test Circuit
V
CM
15pF
50
Ω
50
Ω
125
Ω
125
Ω
50
Ω
50
Ω
R
B
A
B
A
D
V
OD
Figure 3. V.35 Transmitter/Receiver Test Circuit
Test Circuits
Page 8
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, SoftwareSelectable Clock/Data Transceivers
8 _______________________________________________________________________________________
f = 1MHz: tr ≤10ns: tf ≤ 10ns
V
DIFF
= V(A) - V(B)
1.5V
1/2 V
0
V
0
90%
10%
50%
t
PLH
5V
0
V
0
-V
0
D
A
B
B — A
t
r
t
SKEW
1.5V
t
PHL
t
SKEW
90%
10%
50%
t
f
Figure 6. V.11, V.35 Driver Propagation Delays
V
0
-V
0
V
0H
V
0L
B — A
R
0
INPUT
OUTPUT
0
1.5V
f = 1MHz: tr ≤10ns: tf ≤ 10ns
t
PLH
1.5V
t
PHL
Figure 7. V.11, V.35 Receiver Propagation Delays
1.5V
0
t
PHL
3V
0
V
0
-V
0
D
A
-3V
3V
t
r
1.5V
0
t
PLH
3V
-3V
t
r
Figure 8. V.28 Driver Propagation Delays
V
IH
V
IL
V
0H
V
0L
A
R
1.3V
t
PHL
0.8V
1.7V
t
PLH
2.4V
Figure 9. V.28 Receiver Propagation Delays
Timing Diagrams
Page 9
Detailed Description
The MXL1543B is a three-driver/three-receiver, multiprotocol transceiver that operates from a single +5V supply.
The MXL1543B, 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 MXL1543B transceivers carry the
high-speed clock and data signals, while the
MXL1544/MAX3175 transceivers carry serial interface
control signaling. The MXL1543B can be terminated by
the MXL1344A software-selectable resistor termination
network or by a discrete termination network. The
MXL1543B 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 circuitry
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 disabled. When the DCE/DTE input is logic LOW, driver T3
is disabled and receiver R1 is activated. M0, M1, M2,
MXL1543B
+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-.
3VDDGenerated Positive Supply. Connect a 4.7µF ceramic capacitor to ground.
4VCC+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
Noninverting Transmitter Output/Noninverting Receiver Input
20
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-.
T3OUTB/R1INB
T3OUTA/R1INA
Page 10
MXL1543B
and DCE/DTE are internally pulled up to VCCto ensure
a logic HIGH if left unconnected.
No-Cable Mode
The MXL1543B will enter no-cable mode when the
mode-select pins are left unconnected or connected
high (M0 = M1 = M2 = 1). In this mode, the multiprotocol drivers and receivers are disabled and the supply
current drops to 0.5µA. The receivers’ outputs enter a
high-impedance state in no-cable mode, which allow
these output lines to be shared with other receivers’
outputs (the receivers’ outputs have internal pullup
resistors to pull the outputs HIGH if not driven). Also, in
no-cable mode, the transmitter outputs enter a highimpedance state so that these output lines can be
shared with other devices.
Dual Charge-Pump Voltage Converter
The MXL1543B’s internal power supply consists of a
regulated dual charge pump that provides positive and
negative output voltages from a +5V supply. The
charge pump operates in discontinuous mode. If the
output voltage is less than the regulated voltage, the
charge pump is enabled. If the output voltage exceeds
the regulated voltage, the charge pump is disabled.
Each charge pump requires a flying capacitor (C1, C2)
and a reservoir capacitor (C3, C5) to generate the V
DD
and VEEsupplies. Figure 10 shows charge-pump connections.
Fail-Safe Receivers
The MXL1543B guarantees a logic-high receiver output
when the receiver inputs are shorted or open, or when
they are connected to a terminated transmission line
with all the drivers disabled. This is done by setting the
receivers’ threshold between -25mV and -200mV in the
V.11 and V.35 modes. If the differential receiver input
+5V Multiprotocol, 3Tx/3Rx, SoftwareSelectable Clock/Data Transceivers
10 ______________________________________________________________________________________
MXL1543B
MODE NAME
M2 M1 M0
DCE/
DTE
T1 T2 T3 R1 R2 R3
Not Used (Default V.11)
0000V.11V.11 Z V.11 V.11 V.11
RS-530A 0 0 1 0 V.11 V.11 Z V.11 V.11 V.11
RS-530 0 1 0 0 V.11 V.11 Z V.11 V.11 V.11
X.21 0 1 1 0 V.11 V.11 Z V.11 V.11 V.11
V.35 1 0 0 0 V.35 V.35 Z V.35 V.35 V.35
RS-449/V.36 1 0 1 0 V.11 V.11 Z V.11 V.11 V.11
V.28/RS-232 1 1 0 0 V.28 V.28 Z V.28 V.28 V.28
No Cable 1 1 1 0 Z Z Z Z Z Z
Not Used (Default V.11)
0001V.11V.11 V.11 Z V.11 V.11
RS-530A 0 0 1 1 V.11 V.11 V.11 Z V.11 V.11
RS-530 0 1 0 1 V.11 V.11 V.11 Z V.11 V.11
X.21 0 1 1 1 V.11 V.11 V.11 Z V.11 V.11
V.35 1 0 0 1 V.35 V.35 V.35 Z V.35 V.35
RS-449/V.36 1 0 1 1 V.11 V.11 V.11 Z V.11 V.11
V.28/RS-232 1 1 0 1 V.28 V.28 V.28 Z V.28 V.28
No Cable 1 1 1 1 Z Z Z Z Z Z
Table 1. Mode Selection
C2-
V
EE
C2+
MXL1543B
GND
C1-
5V
V
CC
V
DD
C1+
C1
1µF
C5
4.7µF
C2
1µF
C3
4.7µF
C4
1µF
Figure 10. Charge Pump
Page 11
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceivers
______________________________________________________________________________________ 11
CTS A
4
25
21
18
2
14
24
11
15
12
17
9
3
16
7
19
20
23
8
10
6
22
5
13
CTS B
DSR A
DSR B
DCD A
DCD B
DTR A
DTR B
RTS A
RTS B
RXD A
RXD B
RXC A
RXC B
TXC A
TXC B
SCTE A
SCTE B
TXD A
TXD B
CHARGE
PUMP
DTE
DCE
RTS A
RTS B
DTR A
DTR B
DCD A
DCD B
DSR A
DSR B
CTS A
CTS B
TXD A
TXD B
SCTE A
SCTE B
TXC A
TXC B
RXC A
RXC B
RXD A
RXD B
SG
M2
C12
1µF
C13
1µF
C5
4.7µF
C2
1µF
C1
1µF
C4
1µF
C3
4.7µF
2
21
D1
D2
D3
R1
R2
R3
28
27
26
25
24
23
22
21
20
19
18
17
16
15
3
V
CC
5V
1
2
4
5
6
7
8
9
10
11
12
13
14
14
3
4679101615 18 17 19 20 22 23 24 15
8111213
C6
100pFC7100pFC8100pF
M1
M0
DCE/DTE
M1
M2
DCE/DTE
M0
V
CC
V
CC
V
CC
V
EE
V
EE
V
CC
V
DD
GND
LATCH
MXL1344A
MXL1543B
D1
D2
D3
D4
R1
R2
R3
26
27
28
25
24
23
22
21
20
19
18
17
5
6
7
8
9
4
3
1
2
R4
16
15
10
11
12
13
NC
NC
14
M1
M2
DCE/DTE INVERT
M0
DB-25
CONNECTOR
MXL1544
MAX3175
C11
1µF
C10
1µF
C9
1µF
1
SHIELD
DTE_TXD/DCE_RXD
DTE_SCTE/DCE_RXC
DTE_TXC/DCE_TXC
DTE_RXC/DCE_SCTE
DTE_RXD/DCE_TXD
DTE_RTS/DCE_CTS
DTE_DTR/DCE_DSR
DTE_DCD/DCE_DCD
DTE_DSR/DCE_DTR
DTE_CTS/DCE_RTS
M1
DCE/DTE
M0
Figure 11. Cable-Selectable Multiprotocol DTE/DCE Port
Page 12
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, SoftwareSelectable Clock/Data Transceivers
12 ______________________________________________________________________________________
voltage (B - A) is ≥ -25mV, R_OUT is logic HIGH. If (B A) is ≤ -200mV, R_OUT is logic LOW. In the case of a
terminated bus with all transmitters disabled, the
receiver’s differential input voltage is pulled to zero by
the termination. With the receiver thresholds of the
MXL1543B, this results in a logic HIGH with a 25mV
minimum noise margin.
Applications Information
Capacitor Selection
The capacitors used for the charge pumps, as well as
for supply bypassing, should have a low equivalent
series resistance (ESR) and low temperature coefficient. Multilayer ceramic capacitors with an X7R dielectric offer the best combination of performance, size,
and cost. The flying capacitors (C1, C2) and the
bypass capacitor (C4) should have a value of 1µF,
while the reservoir capacitors (C3, C5) should have a
minimum value of 4.7µF (Figure 10). To reduce the ripple present on the transmitter outputs, capacitors C3,
C4, and C5 can be increased. The values of C1 and C2
should not be increased.
Cable Termination
The MXL1344A software-selectable resistor network is
designed to be used with the MXL1543B. The
MXL1344A multiprotocol termination network provides
V.11- and V.35-compliant termination, while V.28
receiver termination is internal to the MXL1543B. These
cable termination networks provide compatibility with
V.11, V.28, and V.35 protocols. Using the MXL1344A
termination networks provide the advantage of not having to build expensive termination networks out of resistors and relays, manually changing termination
modules, or building custom termination networks
Cable-Selectable Mode
A cable-selectable multiprotocol interface is shown in
Figure 11. The mode control lines M0, M1, and
DCE/DTE are wired to the DB-25 connector. To select
the serial interface mode, the appropriate combination
of M0, M1, and DCE/DTE are grounded within the cable
wiring. The control lines that are not grounded are
pulled high by the internal pullups on the MXL1543B.
The serial interface protocol of the MXL1543B,
MXL1544/MAX3175, and MXL1344A is selected based
on the cable that is connected to the DB-25 interface.
V.11 Interface
As shown in Figure 12, the V.11 protocol is a fully balanced differential interface. The V.11 driver generates a
minimum of ±2V between nodes A and B when a 100Ω
(min) resistance is presented at the load. The V.11
receiver is sensitive to ±200mV differential signals at
receiver inputs A’ and B’. The V.11 receiver rejects
common-mode signals developed across the cable
(referenced from C to C’) of up to ±7V, allowing for
error-free reception in noisy environments. The receiver
inputs must comply with the impedance curve shown in
Figure 13.
For high-speed data transmission, the V.11 specification recommends terminating the cable at the receiver
with a 100Ω resistor. This resistor, although not
required, prevents reflections from corrupting transmitted data. In Figure 14, the MXL1344A is used to terminate the V.11 receiver. Internal to the MXL1344A, S1 is
closed and S2 is open to present a 100Ω minimum differential resistance. The MXL1543B’s internal V.28 termination is disabled by opening S3.
V.35 Interface
Figure 15 shows a fully-balanced, differential standard
V.35 interface. The generator and the load must both
present a 100Ω ±10Ω differential impedance and a
150Ω ±15Ω common-mode impedance as shown by
the resistive T networks in Figure 15. The V.35 driver
generates a current output (±11mA, typ) that develops
an output voltage of ±550mV across the generator and
load termination networks. The V.35 receiver is sensitive to ±200mV differential signals at receiver inputs A’
and B’. The V.35 receiver rejects common-mode sig-
100
Ω
MIN
A
′
B
′
C
′
A
B
C
GND GND
GENERATOR
BALANCED
INTERCONNECTING
CABLE
CABLE
TERMINATION
RECEIVER
LOAD
Figure 12. Typical V.11 Interface
-3.25mA
3.25mA
-10V
+10V
-3V
+3V
V
Z
I
Z
Figure 13. Receiver Input Impedance
Page 13
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceivers
______________________________________________________________________________________ 13
R6
12kΩ
R8
5kΩ
R3
124Ω
R2
52Ω
R1
52Ω
A′
B′
C′
A
B
GND
R5
12kΩ
R7
12kΩ
R4
12kΩ
MXL1344A
MXL1543B
S3
S2
S1
RECEIVER
Figure 16. V.35 Termination and Internal Resistance Networks
R6
12kΩ
R8
5kΩ
R3
124Ω
R2
52Ω
R1
52Ω
A′
B′
C′
A
B
GND
R5
12kΩ
R7
12kΩ
R4
12kΩ
MXL1344A
MXL1543B
S3
S1
RECEIVER
S2
Figure 14. V.11 Termination and Internal Resistance Networks
50Ω
50Ω
125Ω
50Ω
50Ω
125Ω
A′
B′
C′
A
B
C
GND GND
GENERATOR
BALANCED
INTERCONNECTING
CABLE
CABLE
TERMINATION
RECEIVER
LOAD
Figure 15. Typical V.35 Interface
Page 14
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, SoftwareSelectable Clock/Data Transceivers
14 ______________________________________________________________________________________
Figure 17. Typical V.28 Interface
A
′
C
′
A
C
GND GND
GENERATOR
UNBALANCED
INTERCONNECTING
CABLE
CABLE
TERMINATION
RECEIVER
LOAD
Figure 18. V.28 Termination and Internal Resistance Networks
nals developed across the cable (referenced from C to
C’) of up to ±4V, allowing for error-free reception in
noisy environments.
In Figure 16, the MXL1344A is used to implement the
resistive T network that is needed to properly terminate
the V.35 driver and receiver. Internal to the MXL1344A,
S1 and S2 are closed to connect the T-network resistors to the circuit. The V.28 termination resistor (internal
to the MXL1543B) is disabled by opening S3 to avoid
interference with the T-network impedance.
V.28 Interface
The V.28 interface is an unbalanced single-ended interface (Figure 17). The V.28 driver generates a minimum
of ±5V across a 3kΩ load impedance between A’ and
C’. The V.28 receiver has a single-ended input. To aid
in rejecting system noise, the MXL1543B’s V.28 receiver has a typical hysteresis of 0.05V.
Figure 18 shows the MXL1344A’s termination network
disabled by opening S1 and S2. The MXL1543B’s internal 5kΩ V.28 termination is enabled by closing S3.
DTE vs. DCE Operation
Figure 19 shows a DCE or DTE controller-selectable
interface. DCE/DTE (pin 14) switches the port’s mode
of operation. See Table 1.
This application requires only one DB-25 connector,
but separate cables for DCE or DTE signal routing. See
Figure 19 for complete signal routing in DCE and DTE
modes.
Complete Multiprotocol X.21 Interface
A complete DTE-to-DCE interface operating in X.21
mode is shown in Figure 20. The MXL1543B is used to
generate the clock and data signals, and the
MXL1544/MAX3175 generate the control signals and
A′
R1
MXL1344A
52Ω
S1
R3
S2
124Ω
R2
52Ω
B′
C′
A
R5
12kΩ
R8
5kΩ
R6
12kΩ
S3
R7
12kΩ
R4
B
12kΩ
GND
MXL1543B
RECEIVER
Page 15
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceivers
______________________________________________________________________________________ 15
CTS A
4
2
14
24
11
15
12
17
9
3
16
7
19
20
23
8
10
6
22
5
13
18
CTS B
DSR A
DSR B
DCD A
DCD B
DTR A
DTR B
RTS A
RTS B
RXD A
RXD B
RXC A
RXC B
TXC A
TXC B
SCTE A
SCTE B
TXD A
TXD B
CHARGE
PUMP
DTE
DCE
RTS A
RTS B
DTR A
DTR B
DCD A
DCD B
DSR A
DSR B
CTS A
CTS B
LLA
LLA
TXD A
TXD B
SCTE A
SCTE B
TXC A
TXC B
RXC A
RXC B
RXD A
RXD B
SG
M2
C12
1µF
C13
1µF
C5
4.7µF
C2
1µF
C1
1µF
C4
1µF
C3
4.7µF
2
21
D1
D2
D3
R1
R2
R3
28
27
26
25
24
23
22
21
20
19
18
17
16
15
3
V
CC
5V
1
2
4
5
6
7
8
9
10
11
12
13
14
14
3
4679101615 18 17 19 20 22 23 24 15
8111213
C6
100pFC7100pFC8100pF
M1
M0
DCE/DTE
M1
M2
DCE/DTE
M0
V
CC
V
CC
V
EE
V
EE
V
CC
V
DD
GND
LATCH
MXL1344A
MXL1543B
D1
D2
D3
D4
R1
R2
R3
26
27
28
25
24
23
22
21
20
19
18
17
5
6
7
8
9
4
3
1
2
R4
16
15
10
11
12
13
14
M1
M2
DCE/DTE
INVERT
M0
M1
M2
DCE/DTE
M0
DB-25
CONNECTOR
MXL1544
MAX3175
C11
1µF
C10
1µF
C9
1µF
1
SHIELD
DTE_TXD/DCE_RXD
DTE_SCTE/DCE_RXC
DTE_TXC/DCE_TXC
DTE_RXC/DCE_SCTE
DTE_RXD/DCE_TXD
DTE_RTS/DCE_CTS
DTE_DTR/DCE_DSR
DTE_DCD/DCE_DCD
DTE_DSR/DCE_DTR
DTE_CTS/DCE_RTS
DTE_LL/DCE_LL
Figure 19. Multiprotocol DCE/DTE Port
Page 16
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, SoftwareSelectable Clock/Data Transceivers
16 ______________________________________________________________________________________
D1
D2
D3
R3
R2
R1
D1
D2
D3
D4
TXD
SCTE
TXC
RXC
RXD
LL
D4
R4
R4
R3
R2
R1
104Ω
104Ω
104Ω
104Ω
104Ω
MXL1543BMXL1344A
MXL1344AMXL1543B
D1
D2
D3
R3
R2
R1
D3
D2
D1
RTS
DTR
DCD
DSR
CTS
R1
R2
R3
MXL1544
MAX3175
MXL1544
MAX3175
SERIAL
CONTROLLER
TXD
SCTE
TXC
RXC
RXD
RTS
DTR
DCD
DSR
CTS
LL
SERIAL
CONTROLLER
TXD
SCTE
TXC
RXC
RXD
RTS
DTR
DCD
DSR
CTS
LL
DCE
DTE
Figure 20. DCE-to-DTE X.21 Interface
local loopback (LL). The MXL1344A is used to terminate the clock and data signals to support the V.11 protocol for cable termination. The control signals do not
need external termination.
Compliance Testing
A European Standard EN 45001 test report is pending
for the MXL1543B/MXL1544/MXL1344A chipset. A
copy of the test report will be available from Maxim
upon completion.
Page 17
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, Software-
Selectable Clock/Data Transceivers
______________________________________________________________________________________ 17
Chip Information
TRANSISTOR COUNT: 2619
PROCESS: BiCMOS
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
C2+
C2-
V
EE
GND
T1OUTA
T1OUTB
R3INB
T2OUTA
T2OUTB
T3OUTA/R1INA
T3OUTB/R1INB
R2INA
R2INB
R3INA
DCE/DTE
M2
M1
M0
R3OUT
R2OUT
R1OUT
T3IN
T2IN
T1IN
V
CC
V
DD
C1+
C1-
SSOP
TOP VIEW
MXL1543B
Pin Configuration
Page 18
MXL1543B
+5V Multiprotocol, 3Tx/3Rx, SoftwareSelectable Clock/Data Transceivers
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
SSOP.EPS
PACKAGE OUTLINE, SSOP, 5.3 MM
1
1
21-0056
C
REV.DOCUMENT CONTROL NO.APPROVAL
PROPRIETARY INFORMATION
TITLE:
NOTES:
1. D&E DO NOT INCLUDE MOLD FLASH.
2. MOLD FLASH OR PROTRUSIONS NOT TO EXCEED .15 MM (.006").
3. CONTROLLING DIMENSION: MILLIMETERS.
4. MEETS JEDEC MO150.
5. LEADS TO BE COPLANAR WITHIN 0.10 MM.
7.90
H
L
0∞
0.301
0.025
8∞
0.311
0.037
0∞
7.65
0.63
8∞
0.95
MAX
5.38
MILLIMETERS
B
C
D
E
e
A1
DIM
A
SEE VARIATIONS
0.0256 BSC
0.010
0.004
0.205
0.002
0.015
0.008
0.212
0.008
INCHES
MIN
MAX
0.078
0.65 BSC
0.25
0.09
5.20
0.05
0.38
0.20
0.21
MIN
1.73 1.99
MILLIMETERS
6.07
6.07
10.07
8.07
7.07
INCHES
D
D
D
D
D
0.239
0.239
0.397
0.317
0.278
MIN
0.249
0.249
0.407
0.328
0.289
MAX
MIN
6.33
6.33
10.33
8.33
7.33
14L
16L
28L
24L
20L
MAX
N
A
D
e
A1
L
C
HE
N
12
B
0.068
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages
.)
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