MAXIM MXL1544, MAX3175 User Manual

General Description

The MXL1544/MAX3175 are four-driver/four-receiver
multiprotocol transceivers that operate from a single
+5V supply in conjunction with the MXL1543. The
MXL1544/MAX3175, along with the MXL1543 and
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, EIA-530A,
X.21, RS-423), and V.35 protocols. The MXL1544/
MAX3175 transceivers carry serial interface control sig­naling, while the MXL1543 carries the high-speed clock
and data signals. Typically, the MXL1543 is terminated
using the MXL1344A. The MAX3175 is identical to the
MXL1544 except for the addition of a 10µs (typ) glitch
rejection circuit at the receiver inputs. The MXL1544/
MAX3175 are available in 28-pin SSOP packages.

Applications

Data Networking

CSU and DSU

Data Routers

Switches

PCI Cards

Telecommunication Equipment

Features

♦ MXL1544/MAX3175, MXL1543, MXL1344A Chipset

Is Pin Compatible with LTC1544, LTC1543,
LTC1344A Chipset

♦ Chipset Operates from a Single +5V Supply
♦ Software-Selectable DCE/DTE

♦ Supports V.28 (RS-232), V.10/V.11 (RS-449/V.36,

EIA-530, EIA-530A, X.21, RS-423) Protocols

♦ Flow-Through Pin Configuration

♦ True Fail-Safe Operation

♦ Low 0.5µA Shutdown Current (No-Cable Mode)

♦ 10µs Receiver Input Deglitching (MAX3175 Only)

♦ TUV-Certified NET1/NET2 and TBR1/TBR2

Compliant

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-1992; Rev 0; 4/01

Typical Operating Circuit

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.

PART TEMP. RANGE PIN-PACKAGE

MXL1544CAI 0°C to +70°C 28 SSOP
MAX3175CAI 0°C to +70°C 28 SSOP

LL

CTS DSR RTSDTRDCD

MXL1544
MAX3175

D3

DCD B

R1

13

CTS A (106)

CTS B

R2R3

DSR A (109)

DSR B

R4

18 5 10 8 22 6 23 20 19 4 1 7 16 3 9 17 12 15 11 24 14 2

LL A (141)

DTR A (108)

DTR B

DCD A (107)

D1D2

RTS A (105)

RTS B

DB-25 CONNECTOR

RXD RXC TXDTXC SCTE

MXL1543

R1

R2R3

RXC B

RXD A (104)

RXD B

SG (102)

SHIELD (101)

RXC A (115)

D3D4

TXC A (114)

TXC B

SCTE A (113)

SCTE B

D1D2

TXD B

TXD A (103)

MXL1344A

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control Transceivers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +5V, VDD= +6.8V, VEE= -5.6V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

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 to GND Unless Otherwise Noted
Supply Voltages

V

CC

.......................................................................-0.3V to +6V

V

DD

....................................................................-0.3V to +7.2V

V

EE

........................................................................+0.3V to -7V

V

DD

to VEE(Note 1)............................................................13V

Logic Input Voltage

M0, M1, M2, DCE/DTE, INVERT, T_IN..................-0.3V to +6V

Logic Output Voltage

R_OUT....................................................-0.3V to (V

CC

+ 0.3V)

Transmitter Outputs

T_OUT_, T_OUT_/R_IN........................................-15V to +15V

Short-Circuit Duration.............................................Continuous

Receiver Inputs

R_IN_, T_OUT_/R_IN_ .........................................-15V to +15V

Continuous Power Dissipation (T

A

= +70°C)

28-Pin SSOP (derate 11.1mW/°C above +70°C) .........889mW

Operating Temperature Range...............................0°C to +70°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Note 1: VDDand VEE- can have maximum magnitude of 7.2V and 7V, respectively, but their difference cannot exceed 13V.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

POWER SUPPLIES

V

S up p l y C ur r ent ( D C E

C C

M od e) ( D i g i tal Inp uts = G N D or
V

) ( Tr ansm i tter s O utp uts

C C

S tati c)

VEE Supply Current (DCE
Mode) (Digital Inputs = GND
or V

) (Transmitters Outputs

CC

Static)

V

S up p l y C ur r ent ( D C E

D D

M od e) ( D i g i tal Inp uts = G N D or
V

) ( Tr ansm i tter s O utp uts

C C

S tati c)

Internal Power Dissipation
(DCE Mode)

LOGIC INPUTS (M0, M1, M2, DCE/DTE, INVERT, T1IN, T2IN, T3IN, T4IN)

Input High Voltage V
Input Low Voltage V

Logic Input Current I

I

CC

I

EE

I

DD

P

D

IH

IL

IN

RS-530, RS-530A, X.21, no load 2.7

RS-530, RS-530A, X.21, full load 95 120

V.28, no load 1 2

V.28, full load 1 2

No-cable mode, Invert = V

RS-530, RS-530A, X.21, no load 2.1

RS-530, X.21, full load 14

RS-530A, full load 25

V.28, no load 1

V.28, full load 12

No-cable mode 0.5 µA

RS-530, RS-530A, X.21, no load 0.6

RS-530, RS-530A, X.21, full load 1

V.28, no load 1

V.28, full load 12

No-cable mode 0.5 µA

RS-530, RS-530A, X.21, full load 300

V.28, full load 54

T1IN, T2IN, T3IN, T4IN ±10
M0, M1, M2, DCE/DTE, INVERT =

GND
M0, M1, M2, DCE/DTE, INVERT =
V

CC

C C

2.0 V

-100 -50 -30

0.5 10 µA

0.8 V

±10

mA

mA

mA

mW

µA

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +5V, VDD= +6.8V, VEE= -5.6V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

LOGIC OUTPUTS (R1OUT, R2OUT, R3OUT, R4OUT)

Output High Voltage V

Output Low Voltage V

Output Short-Circuit Current I

Output Pullup Current I

OH

OL

SC

L

RECEIVER INPUTS

Receiver Glitch Rejection MAX3175 only 5 10 15 µs

V.11 TRANSMITTER

Open-Circuit Differential Output
Voltage

Loaded Differential Output
Voltage

Change in Magnitude of Output
Differential Voltage

Common-Mode Output Voltage V

Change in Magnitude of Output
Common-Mode Voltage

Short-Circuit Current I

Output Leakage Current I

V

V

∆V

∆V

ODO

ODL

OD

OC

OC

SC

Z

Rise or Fall Time tr, t

t

|t

PHL

t

PLH

PHL

t

PLH

Transmitter Input to Output

Data Skew

Output-to-Output Skew (Figures 2, 5) 3 ns

V.11 RECEIVER

Differential Input Voltage V

Input Hysteresis ∆V

Receiver Input Current I

Receiver Input Resistance R

TH

TH

IN

IN

Rise or Fall Time tr, t

t

|t

PHL

t

PLH

PHL

t

PLH

Receiver Input to Output

Data Skew

I

SOURCE

I

SINK

0 ≤ V

V

= 4mA 3 4.5 V

= 4mA 0.3 0.8 V

≤ V

OUT

CC

= 0, no-cable mode 70 µA

OUT

-50 50 mA

Op en ci r cui t, R = 1.95kΩ ( Fi g ur e 1) ±5V

R = 50Ω (Figure 1), TA = +25°C

0.5

V

✕

ODO

0.67
V

ODO

✕

R = 50Ω (Figure 1) ±2

R = 50Ω (Figure 1) 0.2 V

R = 50Ω (Figure 1) 3 V

R = 50Ω (Figure 1) 0.2 V

V

= GND 150 mA

OUT

-0.25V < V
cable mode

R = 50Ω (Figures 2, 5) 2 15 25 ns

f

,

R = 50Ω (Figures 2, 5) 50 75 ns

­(Figures 2, 5) 3 12 ns

|

< +0.25V, power-off or no-

OUT

±1 ±100 µA

-7V ≤ VCM ≤ 7V -200 200 mV

-7V ≤ VCM ≤ 7V 15 40 mV

-10V ≤V

-10V ≤ V

(Figures 2, 6) 15 ns

f

,

(Figures 2, 6)

­(Figures 2, 6)

|

≤ 10V ±0.66 mA

A,B

≤ 10V 15 30 kΩ

A,B

MXL1544 50 80 ns

MAX3175 10 µs

MXL1544 4 16 ns

MAX3175 1 µs

V

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control Transceivers

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +5V, VDD= +6.8V, VEE= -5.6V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V.10 TRANSMITTER

Open-Circuit Output Voltage
Swing

Output Voltage Swing V

Short-Circuit Current I

Output Leakage Current I

Rise or Fall Time tr, t

Transmitter Input to Output

V.10 RECEIVER

Differential Threshold Voltage V

Input Hysteresis ∆V

Receiver Input Current I

Receiver Input Impedance R

Rise or Fall Time tr, t

V

t

PHL

t

PLH

t

PLH

O

T

SC

Z

f

TH

TH

IN

IN

f

Receiver Input to Output

t

PHL

|t

Data Skew

PHL

t

PLH

V.28 TRANSMITTER

Output Voltage Swing V

Short-Circuit Current I

Output Leakage Current I

O

SC

Z

Output Slew Rate SR RL = 3kΩ, CL = 2500pF (Figures 3, 7) 4 30 V/µs

t

Transmitter Input to Output

PHL

t

PLH

V.28 RECEIVER

Input Low Voltage V

Input High Voltage V

Input Hysteresis V

Input Resistance R

Rise or Fall Time tr, t

IL

IH

HYS

IN

f

RL = 3.9kΩ (Figure 3) ±4 ±6V

RL = 450Ω (Figure 3) ±3.6

RL = 450Ω (Figure 3), TA = +25°C

0.9 x
V

O

VO = GND, TA = +25°C ±150 mA

-0.25V < V
or no-cable mode

RL = 450Ω, C

,

RL = 450Ω, C

< +0.25V, power-off

OUT

= 100pF (Figures 3, 7) 2 µs

L

= 100pF (Figures 3, 7) 1 µs

L

±1 ±100 µA

-250 250 mV

25 50 mV

-10V ≤ VA ≤ 10V ±0.66 mA

-10V ≤ VA ≤ 10V 15 30 kΩ

(Figures 4, 8) 15 ns

MXL1544 55 ns

( Fi g ur es 4, 8)

MAX3175 10 µs

MXL1544 109 ns

MAX3175 10 µs

­|

( Fi g ur es 4, 8)

MXL1544 60 ns

MAX3175 1 µs

Open circuit (Figure 3) ±7V

RL = 3kΩ (Figure 3) ±5 ±6V

VO = GND ±150 mA

-0.25V ≤ V
no-cable mode

RL = 3kΩ, C

≤ +0.25V, power-off or

OUT

= 2500pF (Figures 3, 7)

L

±1 ±100 µA

1.5 2.5

1.5 3

1.3 0.8 V

2.0 1.3 V

0.05 0.3 V

-15V < VIN < +15V 3 5 7 kΩ

(Figures 4, 8) 15 ns

V

µs

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +5V, VDD= +6.8V, VEE= -5.6V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

Note 2: MXL1544/MAX3175 are designed to operate with VDDand VEEsupplied by the MXL1543 charge pump.

0.65

0.66

0.67

0.68

0.69

0.70

0.71

0.72

0.73

0 50 100 150 200 250

V.28 MODE SUPPLY CURRENT (ICC)

vs. DATA RATE

MXL1544/MAX3175 toc04

DATA RATE (kbps)

I

CC

(mA)

DCE MODE
INVERT = 0

FULL LOAD (RL = 3kΩ,
C

L

= 2500) AND NO LOAD

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

t

PLH

Receiver Input to Output

t

PHL

(Figures 4, 8)

MXL1544 60 100 ns

MAX3175 10 µs

MXL1544 70 450 ns

MAX3175 10 µs

V.11 MODE SUPPLY CURRENT (ICC)

vs. DATA RATE

120

FULL LOAD, R = 50Ω

100

80

DCE MODE
INVERT = 1

(mA)

60

CC

I

40

20

NO LOAD, R = 1.95kΩ

0

0.1 1 10 100 1000 10,000

DATA RATE (kbps)

MXL1544/MAX3175 toc01

(mA)

DD

I

V.11 MODE SUPPLY CURRENT (IDD)

vs. DATA RATE

10

DCE MODE

9

INVERT = 1

8

7

6

5

4

3

FULL, R = 50Ω

2

NO LOAD, R = 1.95kΩ

1

0

0.1 1 10 100 1000 10,000
DATA RATE (kbps)

MXL1544/MAX3175 toc02

(mA)

EE

I

V.11 MODE SUPPLY CURRENT (IEE)

vs. DATA RATE

10

DCE MODE

9

INVERT = 1

8

7

6

5

4

FULL, R = 50Ω

3

NO LOAD, R = 1.95kΩ

2

1

0

0.1 1 10 100 1000 10,000
DATA RATE (kbps)

MXL1544/MAX3175 toc03

-300

-100

-200

100

0

200

300

-10 0-5 5 10

V.11 RECEIVER INPUT CURRENT

vs. INPUT VOLTAGE

MXL1544/MAX3175 toc10

INPUT VOLTAGE (V)

INPUT CURRENT (µA)

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control Transceivers

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(TA = +25°C, unless otherwise noted.)

V.28 MODE SUPPLY CURRENT (IDD)

vs. DATA RATE

MXL1544/MAX3175 toc05

DATA RATE (kbps)

I

DD

(mA)

0

5

15

10

20

25

010050 150 200 250

DCE MODE
INVERT = 0

NO LOAD

FULL LOAD, RL = 3k

Ω,

CL = 2500pF

0

10

5

20

15

30

25

35

010050 150 200 250

V.28 MODE SUPPLY CURRENT (IEE)

vs. DATA RATE

MXL1544/MAX3175 toc06

DATA RATE (kbps)

I

EE

(mA)

DCE MODE
INVERT = 0

FULL LOAD, RL = 3kΩ,
C

L

= 2500pF

NO LOAD

-5

-2

-3

-4

0

-1

4

3

2

1

5

0 10203040506070

V.11 LOADED DIFFERENTIAL OUTPUT

VOLTAGE vs. TEMPERATURE

MXL1544/MAX3175 toc07

TEMPERATURE (°C)

DIFFERENTIAL OUTPUT VOLTAGE (V)

DCE MODE
INVERT = 1
R

L

= 50Ω

V

OUT+

V

OUT-

-10

-4

-6

-8

0

-2

8

6

4

2

10

0 10203040506070

V.28 LOADED OUTPUT VOLTAGE

vs. TEMPERATURE

MXL1544/MAX3175 toc09

TEMPERATURE (°C)

OUTPUT VOLTAGE (V)

DCE MODE
R

L

= 3kΩ

V

OUT-

V

OUT+

-10

-4

-6

-8

0

-2

8

6

4

2

10

0 10203040506070

V.10 LOADED OUTPUT VOLTAGE

vs. TEMPERATURE

MXL1544/MAX3175 toc08

TEMPERATURE (°C)

OUTPUT VOLTAGE (V)

V

OUT+

V

OUT-

DCE MODE
R

L

= 450Ω

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

_______________________________________________________________________________________ 7

Typical Operating Characteristics (continued)

(TA = +25°C, unless otherwise noted.)

V.28 RECEIVER INPUT CURRENT

vs. INPUT VOLTAGE

5

4

3

2

1

0

-1

INPUT CURRENT (mA)

-2

-3

-4

-5

-15 -5-10 0 5 10 15
INPUT VOLTAGE (V)

V.10 TRANSMITTER RISE AND FALL TIME

vs. LOAD CAPACITANCE

3.5

3.0

2.5

2.0

1.5

RISE/FALL TIME (µs)

1.0

0.5

RISE

FALL

V.28 SLEW RATE vs. LOAD CAPACITANCE

18

16

14

MXL1544/MAX3175 toc11

MXL1544/MAX3175 toc13

12

10

8

SLEW RATE (V/µs)

6

4

2

0

020001000 3000 4000 5000

SLEW+

SLEW-

CAPACITANCE (pF)

MXL1544 LOOPBACK SCOPE PHOTO

V.11 MODE (UNLOADED)

T

IN

T

/

OUT

R

IN

R

OUT

MXL1544/MAX3175 toc14

MXL1544/MAX3175 toc12

5V/div

5V/div

5V/div

0

0 1000 1500500 2000 2500 3000

CAPACITANCE (pF)

MXL1544 LOOPBACK SCOPE PHOTO

V.28 MODE (LOADED)

T

IN

T

/

OUT

R

IN

R

OUT

MXL1544/MAX3175 toc15

4µs/div

5V/div

5V/div

5V/div

MXL1544 LOOPBACK SCOPE PHOTO

T

IN

T

/

OUT

R

IN

R

OUT

4µs/div

V.10 MODE (LOADED)

MXL1544/MAX3175 toc16

4µs/div

5V/div

5V/div

5V/div

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control Transceivers

8 _______________________________________________________________________________________

Pin Description

PIN NAME FUNCTION

1VCC+5V Supply Voltage (±5%). Bypass with a 1µF capacitor to ground.

2VDDPositive Supply Generated by MXL1543. Bypass with a 1µF capacitor to ground.

3 T1IN Transmitter 1 TTL-Compatible Input

4 T2IN Transmitter 2 TTL-Compatible Input

5 T3IN Transmitter 3 TTL-Compatible Input

6 R1OUT Receiver 1 CMOS Output

7 R2OUT Receiver 2 CMOS Output

8 R3OUT Receiver 3 CMOS Output

9 T4IN Transmitter 4 TTL-Compatible Input

10 R4OUT Receiver 4 CMOS Output

11 M0 TTL-Compatible Mode Select Pin with Internal Pullup to V

12 M1 TTL-Compatible Mode Select Pin with Internal Pullup to V

13 M2 TTL-Compatible Mode Select Pin with Internal Pullup to V
14 DCE/DTE TTL-Compatible Input with Internal Pullup to VCC. Logic level high selects DCE interface.

15 INVERT TTL Inp ut w i th Inter nal P ul l up to V

16 T4OUTA/R4INA Transmitter Output/Inverting Receiver Input

17 R3INB Noninverting Receiver Input

18 R3INA Inverting Receiver Input

19 R2INB Noninverting Receiver Input

20 R2INA Inverting Receiver Input

21 T3OUTB/R1INB Noninverting Transmitter Output/Noninverting Receiver Input

22 T3OUTA/R1INA Inverting Transmitter Output/Inverting Receiver Input

23 T2OUTB Noninverting Transmitter Output

24 T2OUTA Inverting Transmitter Output

25 T1OUTB Noninverting Transmitter Output

26 T1OUTA Inverting Transmitter Output

27 GND Ground

28 V

EE

Negative Supply Generated by MXL1543. Bypass with a 1µF capacitor to ground.

CC

CC

CC

. IN V E RT = H IGH r ever ses acti on of D C E /DTE for C hannel 4.

C C

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

_______________________________________________________________________________________ 9

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 car­ries 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 ther­mal shutdown circuitry places the driver outputs into a
high-impedance state. The MAX3175 deglitching fea­ture 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
DCE/DTE are internally pulled up to V

CC

to ensure logic

HIGH if left unconnected.

Figure 1. V.11 DC Test Circuit

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

Figure 2. V.11 AC Test Circuit

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

Test Circuits

V

OD

B

D

A

100Ω

100pF

R

V

R

B

A

OC

R

15pF

DA

V

C

O

L

DAR

R

L

15pF

100pF

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control Transceivers

10 ______________________________________________________________________________________

Figure 5. V.11, V.35 Driver Propagation Delays

Figure 6. V.11, V.35 Receiver Propagation Delays

Figure 7. V.10, V.28 Driver Propagation Delays

Figure 8. V.10, V.28 Receiver Propagation Delays

Switching Time Waveforms

5V

B-A

D

0

V

0

-V

0

A

B

V

1.5V

t

PLH

50%

0

90%
10%

t

r

t

SKEW

V

0D2

-V

0D2

V

0H

R

V

0L

B-A

0

t

PLH

1.5V

3V

D

0

V

0

A

-V

0

1.5V

t

PHL

3V

0

t

f

f = 1MHz: tr ≤ 10ns: tf ≤ 10ns

V

DIFF

1/2 V

0

f = 1MHz: tr ≤ 10ns: tf ≤ 10ns

-3V

= V(B) - V(A)

INPUT

OUTPUT

1.5V

0

t

PHL

90%

t

PLH

-3V

50%

10%

t

f

t

SKEW

0

t

PHL

1.5V

3V

0

t

r

V

IH

A

V

IL

V

0H

R

V

0L

1.3V

t

PHL

0.8V

1.7V

t

PLH

2.4V

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

______________________________________________________________________________________ 11

The MXL1544/MAX3175s’ mode can be selected
through software control of the M0, M1, M2, INVERT,
and DCE/DTE inputs. Alternatively, the mode can be
selected by shorting the appropriate combination of
mode control inputs to GND (the inputs left floating will
be internally pulled up to VCC- logic HIGH). If the M0,
M1, and M2 mode inputs are all unconnected, the
MXL1544/MAX3175 will enter no-cable mode.

Fail-Safe

The MXL1544/MAX3175 guarantee 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 drivers disabled. The V.11
receiver threshold is set between -200mV and 0mV to
guarantee fail-safe operation. If the differential receiver
input voltage (B - A) is ≥ 0mV, ROUT is logic HIGH. In
the case of a terminated bus with all transmitters dis­abled, the receiver’s differential input voltage is pulled
to 0 by the termination. With the receiver thresholds of
the MXL1544/MAX3175, this results in ROUT logic
HIGH.

The V.10 receiver threshold is set between -250mV and
0mV. If the V.10 receiver input voltage is less than or
equal to -250mV, ROUT is logic HIGH. The V.28 receiv­er threshold is set between 0.8V and 2.0V. If the receiv­er input voltage is less than or equal to 0.8V, ROUT is
logic HIGH. In the case of a terminated bus with trans­mitters disabled, the receiver’s input voltage is pulled
to 0 by the termination.

Applications Information

Cable-Selectable Mode

A cable-selectable, multiprotocol DTE/DCE interface is
shown in Figure 9. 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, M2, 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 MXL1543.
The serial interface protocol of the MXL1544/MAX3175
is now selected based on the cable that is connected
to the DB-25 interface.

V.10 (RS-423) Interface

The V.10 interface (Figure 10) is an unbalanced single­ended interface capable of driving a 450Ω load. The
V.10 driver generates a minimum VOvoltage of ±4V
across A’ and C’ when unloaded and a minimum volt­age of 0.9 ✕VOwhen loaded with 450Ω. The V.10
receiver has a single-ended input and does not reject
common-mode differences between C and C’. The V.10
receiver input trip threshold is defined between

+250mV and -250mV with input impedance character­istic shown in Figure 11.

The MXL1544/MAX3175 V.10 mode receiver has a dif­ferential threshold between -250mV and +250mV. To
ensure that the receiver has proper fail-safe operation
see the Fail-Safe section. To aid in rejecting system
noise, the MXL1544/MAX3175 V.10 receiver has a typi­cal hysteresis of 25mV. Switch S3 in Figure 12 is open
in V.10 mode to disable the V.28 5kΩ termination at the
receiver input. Switch S4 is closed and switch S5 is
open to internally ground the receiver B input.

V.11 (RS-422) Interface

As shown in Figure 13, 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 100Ω
minimum resistance is presented at the load. The V.11
receiver is sensitive to differential signals of ±200mV at
receiver inputs A’ and B’. The V.11 receiver input must
comply with the impedance curve of Figure 11 and
reject common-mode signals developed across the
cable (referenced from C to C’ in Figure 13) of up to
±7V.

The MXL1544/MAX3175 V.11 mode receiver has a dif­ferential threshold between -200mV and +200mV. To
ensure that the receiver has proper fail-safe operation;
see the Fail-Safe section. To aid in rejecting system
noise, the MXL1544/MAX3175 V.11 receiver has a typi­cal hysteresis of 15mV. Switch S3 in Figure 14 is open
in V.11 mode to disable the V.28 5kΩ termination at the
inverting receiver input. Because the control signals are
slow (60kbps), 100Ω termination resistance is generally
not required for the MXL1544/MAX3175. The receiver
inputs must also be compliant with the impedance
curve shown in Figure 11.

V.28 (RS-232) Interface

The V.28 interface is an unbalanced single-ended inter­face (Figure 10). The V.28 generator provides a mini­mum of ±5V across the 3kΩ load impedance between
A’ and C’. The V.28 receiver has single-ended input.

The MXL1544/MAX3175 V.28 mode receiver has a
threshold between +0.8V and +2.0V. To aid in rejecting
system noise, the MXL1544/MAX3175 V.28 receiver
has a typical hysteresis of 50mV. Switch S3 in Figure 15
is closed in V.28 mode to enable the 5kΩ V.28 termina­tion at the receiver inputs.

No-Cable Mode

The MXL1544/MAX3175 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

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control Transceivers

12 ______________________________________________________________________________________

Figure 9. Cable-Selectable Multiprotocol DCE/DTE Port with DB-25 Connector

C6

100pFC7100pFC8100pF

3

8111213

V

CC

5V

1µF

C1

C4
1µF

NC

V

NC

10

11

12
13
14

CC

10

11

12
13
14

3

1

CHARGE

2

PUMP

4

5

D1

6

D2

7

D3

8

R1

9

R2

R3

MXL1543

M0
M1
M2
DCE/DTE

1

V

CC

2

V

DD

3

D1

4

D2

5

D3

6

R1

7

R2

8

R3

R4

9

D4

MXL1544

M0

MAX3175

M1
M2
DCE/DTE INVERT

C3

4.7µF

DTE_TXD/DCE_RXD

DTE_SCTE/DCE_RXC

DTE_TXC/DCE_TXC

DTE_RXC/DCE_SCTE

DTE_RXD/DCE_TXD

C10
1µF

DTE_RTS/DCE_CTS

DTE_DTR/DCE_DSR

DTE_DCD/DCE_DCD

DTE_DSR/DCE_DTR

DTE_CTS/DCE_RTS

1µF

C9

GND

14

V

C13

C2
1µF

C5

4.7µF

1µF

MODE

V.35
RS-449. V.36
RS-232

28

27
26

25

24
23
22
21

20
19

18
17
16
15

28

V

EE

27

26
25
24
23

22
21

20
19
18
17

16

15

CC

2

V

EE

C12
1µF

C11
1µF

CABLE WIRING FOR

MODE SELECTION

PIN 18

PIN 7
N.C.
PIN 7

4 6 7 9 10 16 15 18 17 19 20 22 23 24 15

PIN 21

PIN 7
PIN 7
N.C.

CABLE WIRING FOR

DTE/DCE SELECTION

PIN 25

MODE

PIN 7

DTE

N.C.

DCE

MXL1344A

DCE/DTE

M2

V

CC

LATCH

M1

21

M0

DCE

DTE

2

RXD A

TXD A

14

RXD B

TXD B

24

RXC A

SCTE A

11

RXC B

SCTE B

15

TXC A

TXC A

12

TXC B

TXC B

17

SCTE A

RXC A

9

SCTE B

RXC B

3

TXD A

RXD A

16

TXD B

RXD B

7

SG

1

SHIELD

DB-25

CONNECTOR

25

DCE/DTE

21

M1

18

M0

4

CTS A

RTS A

19

RTS B

20
23

10

22

13

CTS B

DSR A

DTR A
DTR B

DSR B

8

DCD A

DCD A

DCD B

DCD B

6

DTR A

DSR A

DTR B

DSR B

5

RTS A

CTS A

RTS B

CTS B

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

______________________________________________________________________________________ 13

supply current is less than 10µA. The receiver outputs
enter a high-impedance state in no-cable mode, which
allows these output lines to be shared with other receiv­er outputs (the receiver outputs have an internal pullup
resistor to pull the outputs HIGH if not driven). Also, in
no-cable mode, the transmitter outputs enter a high­impedance state, so these output lines can be shared
with other devices.

Receiver Glitch Rejection

To improve operation in an unterminated or otherwise
noisy system, the MAX3175 features 10µs of receiver
input glitch rejection. The glitch-rejection circuitry
blocks the reception of high-frequency noise (tB< 5µs)
while receiving a low-frequency signal (t

B

>15µs) allow­ing glitch-free operation in unterminated systems at up
to 60kbps. The MXL1544 does not have this feature
and can be operated at frequencies greater than
60kbps if properly terminated.

Figure 10. Typical V.10/V.28 Interface

Figure 11. Receiver Input Impedance Curve

Figure 12. V.10 Internal Resistance Network

Figure 13. Typical V.11 Interface

GENERATOR

I

Z

-10V

-3.25mA

-3V

+3V

A

C

UNBALANCED

INTERCONNECTING

CABLE

3.25mA

V

Z

+10V

LOAD

CABLE

TERMINATION

A′

C′

BALANCED

GENERATOR

INTERCONNECTING

A

B

C

CABLE

RECEIVER

TERMINATION

A′

B′

C′

CABLE

100Ω

MIN

LOAD

RECEIVER

A′

A

R5

30kΩ

R8

5kΩ

S3

R4

GND

30kΩ

S4

B′

B

C′

10kΩ

10kΩ

S5

R6

R7

MXL1544
MAX3175

RECEIVER

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control Transceivers

14 ______________________________________________________________________________________

DTE vs. DCE Operation

Figure 16 shows a port with one DB-25 connector that
can be configured for either DTE or DCE operation. The
configuration requires separate cables for proper sig­nal routing in DTE or DCE operation. Figure 16 illus­trates a DCE or DTE controller-selectable interface. The
DCE/DTE and INVERT inputs switch the port’s mode of
operation (Table 1).

The MXL1543 and MXL1544/MAX3175 can be connect­ed for either DTE or DCE operation in one of two ways:
a dedicated DTE or DCE port with an appropriate gen­der connector or a port with a connector that can be
configured for DTE or DCE operation by rerouting the
signals to the MXL1543 and MXL1544/MAX3175 using

a dedicated DTE cable or dedicated DCE cable. The
interface mode is selected by logic outputs from the
controller or from jumpers to either VCCor GND on the
mode select pins. A dedicated DCE port using a DB-25
female connector is shown in Figure 17. Figure 18 illus­trates a dedicated DTE port using a DB-25 male con­nector.

Figure 15. V.28 Termination and Internal Resistance NetworkFigure 14. V.11 Internal Resistance Networks

A′

A

R5

30kΩ

R8
5kΩ

10kΩ

R6

MXL1544
MAX3175

RECEIVER

A′

A

R5

30kΩ

R8
5kΩ

10kΩ

R6

MXL1544
MAX3175

RECEIVER

S3

R7

R4

B

B′

C′

30kΩ

GND

10kΩ

S3

R7

10kΩ

R4

B′

B

C′

GND

30kΩ

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

______________________________________________________________________________________ 15

Table 1. Mode Select Table

PROTOCOL M2 M1 M0

Not Used
(Default V.11)

RS-530A 0 0 1 0 0 V.11 V.10 Z V.11 V.10 V.11 Z V.10

RS-530 0 1 0 0 0 V.11 V.11 Z V.11 V.11 V.11 Z V.10

X.21 0 1 1 0 0 V.11 V.11 Z V.11 V.11 V.11 Z V.10

V.35 1 0 0 0 0 V.28 V.28 Z V.28 V.28 V.28 Z V.28

RS-449/V.36 1 0 1 0 0 V.11 V.11 Z V.11 V.11 V.11 Z V.10

V.28/RS-232 1 1 0 0 0 V.28 V.28 Z V.28 V.28 V.28 Z V.28

No Cable 1 1 1 0 0 Z Z Z Z Z Z Z Z

Not Used
(Default V.11)

RS-530A 0 0 1 0 1 V.11 V.10 Z V.11 V.10 V.11 V.10 Z

RS-530 0 1 0 0 1 V.11 V.11 Z V.11 V.11 V.11 V.10 Z

X.21 0 1 1 0 1 V.11 V.11 Z V.11 V.11 V.11 V.10 Z

V.35 1 0 0 0 1 V.28 V.28 Z V.28 V.28 V.28 V.28 Z

RS-449/V.36 1 0 1 0 1 V.11 V.11 Z V.11 V.11 V.11 V.10 Z

V.28/RS-232 1 1 0 0 1 V.28 V.28 Z V.28 V.28 V.28 V.28 Z

No Cable 1 1 1 0 1 Z Z Z Z Z Z Z Z

Not Used
(Default V.11)

RS-530A 0 0 1 1 0 V.11 V.10 V.11 Z V.10 V.11 V.10 Z
RS-530 0 1 0 1 0 V.11 V.11 V.11 Z V.11 V.11 V.10 Z
X.21 0 1 1 1 0 V.11 V.11 V.11 Z V.11 V.11 V.10 Z
V.35 1 0 0 1 0 V.28 V.28 V.28 Z V.28 V.28 V.28 Z
RS-449/V.36 1 0 1 1 0 V.11 V.11 V.11 Z V.11 V.11 V.10 Z
V.28/RS-232 1 1 0 1 0 V.28 V.28 V.28 Z V.28 V.28 V.28 Z
No Cable 1 1 1 1 0 Z Z Z Z Z Z Z Z
Not Used
(Default V.11)

RS-530A 0 0 1 1 1 V.11 V.10 V.11 Z V.10 V.11 Z V.10

RS-530 0 1 0 1 1 V.11 V.11 V.11 Z V.11 V.11 Z V.10

X.21 0 1 1 1 1 V.11 V.11 V.11 Z V.11 V.11 Z V.10

V.35 1 0 0 1 1 V.28 V.28 V.28 Z V.28 V.28 Z V.28

RS-449/V.36 1 0 1 1 1 V.11 V.11 V.11 Z V.11 V.11 Z V.10

V.28/RS-232 1 1 0 1 1 V.28 V.28 V.28 Z V.28 V.28 Z V.28

No Cable 1 1 1 1 1 Z Z Z Z Z Z Z Z

0 0 0 0 0 V.11 V.11 Z V.11 V.11 V.11 Z V.10

0 0 0 0 1 V.11 V.11 Z V.11 V.11 V.11 V.10 Z

0 0 0 1 0 V.11 V.11 V.11 Z V.11 V.11 V.10 Z

0 0 0 1 1 V.11 V.11 V.11 Z V.11 V.11 Z V.10

DCE/

DTE

INVERT T1 T2 T3 R1 R2 R3 T4 R4

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control Transceivers

16 ______________________________________________________________________________________

Figure 16. Controller-Selectable Multiprotocol DCE/DTE Port with DB-25 Connector

C6

100pFC7100pFC8100pF

3

8111213

V

CC

5V

1µF

3

1

C1

C4
1µF

10

11

12
13
14

2
4

5

6

7

8

9

CHARGE

D1

D2

D3

MXL1543

M0
M1
M2
DCE/DTE

PUMP

R1

R2

R3

C3

4.7µF

DTE_TXD/DCE_RXD

DTE_SCTE/DCE_RXC

DTE_TXC/DCE_TXC

DTE_RXC/DCE_SCTE

DTE_RXD/DCE_TXD

14

V

C12
1µF

CC

2

V

EE

4 6 7 9 10 16 15 18 17 19 20 22 23 24 15

C13

C2
1µF

C5

4.7µF

1µF

28

27
26

25

24
23
22
21

20
19

18
17
16
15

MXL1344A

DCE/DTE

21

LATCH

M2

M1

M0

DCE

DTE

2

RXD A

TXD A

14

RXD B

TXD B

24

RXC A

SCTE A

11

RXC B

SCTE B

15

TXC A

TXC A

12

TXC B

TXC B

17

SCTE A

RXC A

9

SCTE B

RXC B

3

TXD A

RXD A

16

TXD B

RXD B

7

SG

1

SHIELD

C10
1µF

DTE_RTS/DCE_CTS

DTE_DTR/DCE_DSR

DTE_DCD/DCE_DCD

DTE_DSR/DCE_DTR

DTE_CTS/DCE_RTS

DTE_LL/DCE_LL

INVERT

DCE/DTE

DB-25

4
19
20
23

8
10

6
22

5
13

18

CONNECTOR

RTS A
RTS B

DTR A
DTR B

DCD A
DCD B

DSR A
DSR B

CTS A
CTS B

LL A

CTS A
CTS B

DSR A
DSR B

DCD A
DCD B

DTR A
DTR B

RTS A
RTS B

LL A

C9

V

CC

1µF

M2
M1
M0

10

11

12
13
14

1

2

3

4

5

6

7

8

9

V

CC

V

DD

MXL1544

M0

MAX3175

M1
M2

DCE/DTE

28

V

EE

27

GND

26

D1

25
24

D2

23

D3

22
21

R1

20

R2

19
18

R3

17

16

R4

D4

15

INVERT

C11
1µF

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

______________________________________________________________________________________ 17

Figure 17. Controller-Selectable DCE Port with DB-25 Connector

C10
1µF

RXD

RXC

TXC

SCTE

TXD

CTS

DSR

DCD

DTR

RTS

INVERT

C6

100pFC7100pFC8100pF

3

8111213

V

CC

5V

1µF

3

1

C1

2
4

C4
1µF

5

6

7

8

9

10

11

MXL1543

M0

12

M1

13

M2

14

NC

DCE/DTE

V

CC

1

V

CC

2

V

DD

3

4

5

6

7

8

10

9

MXL1544

11

M0

MAX3175

12

M1

13

M2

14

NC

DCE/DTE

C3

4.7µF

C9

1µF

LL

M2
M1
M0

CHARGE

PUMP

D1

D2

D3

R1

R2

R3

D1

D2

D3

R1

R2

R3

R4

D4

GND

INVERT

28

C2
1µF

27
26

C5

4.7µF

25

24
23
22
21

20
19

18
17
16
15

28

V

EE

27

26
25
24
23

22
21

20
19
18
17

16

15

1µF

C13

C11
1µF

14

C12
1µF

V

CC

2

V

EE

4 6 7 9 10 16 15 18 17 19 20 22 23 24 15

V

CC

DCE/DTE

MXL1344A

M2

LATCH

M1

21

M0

3

RXD A (104)

16

RXD B

17

RXC A (115)

9

RXC B

15

TXC A (114)

12

TXC B

24

SCTE A (113)

11

SCTE B

2

TXD A (103)

14

TXD B

7

SGND (102)

1

SHIELD (101)

DB-25

FEMALE

CONNECTOR

5

CTS A (106)

13

CTS B

6

DSR A (107)

22

DSR B

8

DCD A (109)

10

DCD B

20

DTR A (108)

23

DTR B

4

RTS A (105)

19

RTS B

18

LL A (141)

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control Transceivers

18 ______________________________________________________________________________________

Figure 18. Controller-Selectable Multiprotocol DTE Port with DB-25 Connector

C6

100pFC7100pFC8100pF

3

8111213

V

CC

5V

1µF

3

1

C1

C4
1µF

10

11

12
13
14

2
4

5

6

7

8

9

CHARGE

D1

D2

D3

MXL1543

M0
M1
M2
DCE/DTE

PUMP

R1

R2

R3

C3

4.7µF

TXD

SCTE

TXC

RXC

RXD

14

V

C12
1µF

CC

2

V

EE

4 6 7 9 10 16 15 18 17 19 20 22 23 24 15

C13

C2
1µF

C5

4.7µF

1µF

28

27
26

25

24
23
22
21

20
19

18
17
16
15

MXL1344A

DCE/DTE

M2

LATCH

M1

21

M0

2

TXD A (103)

14

TXD B

24

SCTE A (113)

11

SCTE B

15

TXC A (114)

12

TXC B

17

RXC A (115)

9

RXC B

3

RXD A (104)

16

RXD B

7

SG

1

SHIELD

C9

V

CC

C10
1µF

RTS

DTR

DCD

DSR

CTS

INVERT

1µF

LL

M2
M1
M0

10

11

12
13
14

1

2

3

4

5

6

7

8

9

V

CC

V

DD

MXL1544

M0

MAX3175

M1
M2

DCE/DTE

28

V

EE

27

GND

26

D1

25
24

D2

23

D3

22
21

R1

20

R2

19
18

R3

17

16

R4

D4

15

INVERT

C11
1µF

4

19

20

23

8

10

6

22

5

13

18

DB-25 MALE

CONNECTOR

RTS A (105)
RTS B

DTR A (108)
DTR B

DCD A (109)
DCD B

DSR A (107)
DSR B

CTS A (106)
CTS B

LL A (141)

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable

Control Transceivers

______________________________________________________________________________________ 19

Pin Configuration

Chip Information

TRANSISTOR COUNT: 2348

PROCESS: BiCMOS

TOP VIEW

V

V

T1IN

T2IN

T3IN

R1OUT

R2OUT

R3OUT

T4IN

R4OUT

DCE/DTE

M0

M1

M2

1

CC

2

DD

3

4

5

MXL1544

6

MAX3175

7

8

9

10

11

12

13

14

28

V

EE

27

GND

26

T1OUTA

25

T1OUTB

24

T2OUTA

23

T2OUTB

22

T3OUTA/R1INA

21

T3OUTB/R1INB

20

R2INA

19

R2INB

18

R3INA

17

R3INB

16

T4OUTA/R4INA

15

INVERT

SSOP

MXL1544/MAX3175

+5V Multiprotocol, Software-Selectable
Control 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.

20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

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