Maxim MAX3174CAI 3.3v multiprotocol software-selectable cable terminators and transceiver Datasheet

19-1801; Rev 1; 1/01
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
Features
♦ Industry’s First +3.3V Multiprotocol Termination
Networks and Transceivers
♦ Certified TBR-1 and TBR-2 Compliant
(NET1 and NET2)
♦ Support V.28 (RS-232), V.11 (RS-422, RS-530, RS530A, RS-449, V.36, and X.21), V.10 and V.35
♦ 3V/5V Logic-Compatible I/O
♦ Software-Selectable DTE/DCE
♦ Replace Discrete Resistor Termination Networks
and Expensive Relays
♦ 10µs Receiver Input Deglitching (MAX3172 only)
♦ Available in Small 28-Pin SSOP Package
♦ Transmitter Output Fault Protected to ±15V,
Tolerates Cable Miswiring
Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX3172CAI
0°C to +70°C
28 SSOP
MAX3174CAI
0°C to +70°C
28 SSOP
________________________Applications
Data Networking
CSU and DSU
Data Routers
MAX3171
MAX3173
PCI Cards
Telecommunications
Pin Configuration appears at end of data sheet.
Typical Operating Circuit
CTS
DSR
R3
R2
R1
DCD
DTR
RTS
D3
D2
D1
LL
RXD
RXC
R3
R2
TXC
R1
D3
SCTE TXD
D2
D1
MAX3170
MAX3172
MAX3174
R4
12 15 11 24 14 2
TXD B
TXD A
9 17
SCTE B
SCTE A
DB-25 CONNECTOR
16 3
TXC B
TXC A
18
RXD B
RXD A
RXC B
RXC A
7
LL A
DCD B
DCD A
1
SG
DSR B
DSR A
23 20 19 4
SHIELD
22 6
RTS B
RTS A
10 8
DTR B
DTR A
13 5
CTS B
CTS A
D4
________________________________________________________________ Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX3172/MAX3174
General Description
The MAX3172/MAX3174 contain five software-selectable multiprotocol cable termination networks. Each
network is capable of terminating V.11 (RS-422, RS530, RS-530A, RS-449, V.36, and X.21) with a 100Ω differential 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 devices replace discrete resistor termination networks and expensive relays required for multiprotocol
termination. The MAX3172/MAX3174, along with the
MAX3170 and MAX3171/MAX3173, form a complete
+3.3V software-selectable DTE or DCE interface port
supporting V.11/RS-422, RS-530, RS-530A, V.36/RS449, V.35, V.28/RS-232, V.10/RS-423, and X.21 serial
interfaces.
In addition to the five multiprotocol cable termination
networks, the MAX3172/MAX3174 contain a 1Tx/1Rx
multiprotocol transceiver designed to use V+ and Vgenerated by the MAX3171/MAX3173 charge pump.
The MAX3172/MAX3174 transceiver is software selectable between V.10 and V.28 modes of operation. The
MAX3172 features 10µs deglitching on the V.10/V.28
receiver input to facilitate unterminated operation, while
the MAX3174 is used in applications that do not require
deglitching on the serial handshake signals. These
devices are available in a 28-pin SSOP package.
MAX3172/MAX3174
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND unless otherwise noted.)
Supply Voltages
VCC ......................................................................-0.3V to +4V
V+ (Note 1) ..........................................................-0.3V to +7V
V- (Note 1) ...........................................................+0.3V to -7V
V+ to V- (Note 1) ...............................................................13V
Logic Input Voltages
M0, M1, M2, DCE/DTE, INVERT, T4IN ................-0.3V to +6V
Logic Output Voltages
R4OUT...................................................-0.3V to (VCC + 0.3V)
Short-Circuit Duration............................................Continuous
Transmitter Outputs
T4OUT ................................................................-15V to +15V
Short-Circuit Duration ........................................................60s
Receiver Input
R4INA .................................................................-15V to +15V
Termination Network Inputs (applied individually)
R_A, R_B ............................................................-15V to +15V
Continuous Power Dissipation (TA = +70°C)
28-Pin SSOP (derate 9.52mW/°C above +70°C) ........762mW
Operating Temperature Range
MAX3172CAI/MAX3174CAI ...............................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: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
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.
ELECTRICAL CHARACTERISTICS
(VCC = +3.3V ± 5%, TA = TMIN to TMAX. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted. See Note 2 for V+
and V- input voltage conditions.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
All modes V.10 receiver inactive
80
200
All modes V.10 receiver active
No-cable mode
400
750
0.2
1.0
V.10/V.11/V.28/V.35 modes unloaded
0.5
2.5
V.10/V.11 modes T4OUT loaded
11.0
14.0
UNITS
DC CHARACTERISTICS
Supply Current
(Digital Inputs = GND or VCC)
V+ Supply Current
(T4IN = GND)
V- Supply Current
(T4IN = VCC)
ICC
IV+
IV-
V.28/V.35 modes T4OUT loaded
3.0
5.0
No-cable mode
-0.4
-1.0
V.10/V.11/V.28/V.35 modes unloaded
-0.8
-2.5
V.10/V.11 modes T4OUT loaded
-11.0
-14.0
V.28/V.35 modes T4OUT loaded
-3.0
-5.0
µA
mA
mA
TERMINATOR NETWORKS (R_A, R_B)
Differential-Mode Impedance
V.35 Mode
Figure 1, -2V ≤ VCM ≤ +2V
90
104
110
Ω
Common-Mode Impedance
V.35 Mode
Figure 2, -2V ≤ VCM ≤ +2V
135
153
165
Ω
Differential-Mode Impedance
V.11 Mode
Figure 1, -7V ≤ VCM ≤ +7V
100
104
110
Ω
Switches open, -15V ≤ VA ≤ +15V, VB = VA,
VB = GND or VB floating
50
150
Network OFF Impedance
IZ
kΩ
LOGIC INPUTS (M0, M1, M2, INVERT, DCE/DTE, T4IN)
Input High Voltage
VIH
Input Low Voltage
VIL
Logic Input Current
2
IIH, IIL
2.0
VIN = VCC or GND
_______________________________________________________________________________________
V
0.8
V
±1
µA
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
(VCC = +3.3V ± 5%, TA = TMIN to TMAX. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted. See Note 2 for V+
and V- input voltage conditions.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
0.4
V
LOGIC OUTPUT (R4OUT)
Output High Voltage
VOH
ISOURCE = 1.0mA
Output Low Voltage
VOL
ISINK = 1.6mA
Rise or Fall Time
tr, tf
10% to 90%, CL = 15pF
VCC - 1.0
15
R4OUT = GND
Output Leakage Current
(Receiver Output Three-Stated)
V
30
R4OUT = VCC
ns
50
100
0.1
1
µA
TRANSMITTER OUTPUT (T4OUT)
Output Leakage Current
IZ
Data Rate
-0.25V < VT4OUT < +0.25V,
power-off or no-cable mode
-100
V.10/V.28
100
240
µA
kbps
RECEIVER INPUT (R4INA)
Minimum pulse width passed
Receiver Glitch Rejection
(MAX3172 only)
Receiver Input Resistance
5
Maximum pulse width rejected
RIN
Data Rate
15
V.10 enabled, -10V ≤ VR4INA ≤ +10V
20
40
V.28 enabled, -15V ≤ VR4INA ≤ +15V
3
5
MAX3172
64
MAX3174
240
7
µs
kΩ
kbps
V.10 TRANSMITTER
Output Voltage Swing
VODO
RL = 3.9kΩ, Figure 3
Loaded Output Voltage Swing
VODL
RL = 450Ω, Figure 3
±4.0
±4.4
±6.0
0.9 × VODO
V
V
±100
±150
Short-Circuit Current
ISC
T4OUT = GND
Rise or Fall Time
tr, tf
10% to 90%, RL = 450Ω, CL = 100pF,
Figure 3
2
µs
tPHL, tPLH
RL = 450Ω, CL = 100pF, Figure 3
2
µs
| tPHL tPLH |
RL = 450Ω, CL = 100pF, Figure 3
50
ns
Transmitter Propagation Delay
Data Skew
mA
V.10 RECEIVER
Threshold Voltage
VTH
∆VTH
Input Hysteresis
Receiver Propagation Delay
Data Skew
25
100
250
15
tPHL, tPLH
Figure 4
| tPHL tPLH |
Figure 4
MAX3172
5
mV
mV
10
15
µs
MAX3174
60
120
ns
MAX3172
0.5
4
µs
MAX3174
5
16
ns
_______________________________________________________________________________________
3
MAX3172/MAX3174
ELECTRICAL CHARACTERISTICS (continued)
MAX3172/MAX3174
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.3V ± 5%, TA = TMIN to TMAX. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted. See Note 2 for V+
and V- input voltage conditions.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
±5.0
±5.4
MAX
UNITS
V.28 TRANSMITTER
Output Voltage Swing
VO
Short-Circuit Current
ISC
RL = 3kΩ, Figure 3
±6.5
Open circuit, Figure 3
±25
T4OUT = GND
RL = 3kΩ, CL = 2500pF measured from
+3V to -3V or -3V to +3V, Figure 3
Output Slew Rate
Data Skew
mA
30
V/µs
SR
RL = 7kΩ , CL = 150pF measured from
+3V to -3V or -3V to +3V, Figure 3
Transmitter Propagation Delay
4
±60
V
6
30
tPHL, tPLH
1
µs
| tPHL tPLH |
100
ns
V.28 RECEIVER
Input Threshold Low
VIL
Input Threshold High
VIH
Input Hysteresis
Receiver Propagation Delay
Data Skew
1.1
2.0
VHYS
0.8
1.6
V
0.5
tPHL, tPLH
Figure 4
| tPHL tPLH |
Figure 4
MAX3172
MAX3174
5
10
V
15
200
MAX3172
0.5
MAX3174
100
V
µs
ns
4
µs
ns
Note 2: The charge pump on the MAX3171/MAX3173 can supply V+ and V- to the MAX3172/MAX3174. The V+ and V- input levels
vary with the mode of chipset operation as follows:
V.35/V.28 modes: +5.55V ≤ V+ ≤ +6.50V, -6.50V ≤ V- ≤ -5.45V
Typical operation: V+ = +5.90V, V- = -5.80V
V.10/V.11 modes: +4.20V ≤ V+ ≤ +5.0V, -4.60V ≤ V- ≤ -3.80V
Typical operation: V+ = +4.60V, V- = -4.20V
The MAX3171/MAX3173 are guaranteed to provide these V+/V- supply levels.
4
_______________________________________________________________________________________
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
V.28 60kbps TRANSMITTER
WAVEFORM (3kΩ/1000pF LOAD)
V.28 SLEW RATE
vs. LOAD CAPACITANCE
SLEW RATE (V/µs)
MAX3172-01
MAX3172-02
24
22
20
18
16
RL = 3kΩ
5V
+SLEW
T4IN
5V/div
0
14
12
10
8
5V
-SLEW
6
4
2
0
T4OUT
5V/div
0
-5V
500
0
1000
1500
2000
2500
10µs/div
3000
LOAD CAPACITANCE (pF)
V.10 RISE AND FALL TIMES
vs. LOAD CAPACITANCE
V.10 60kbps TRANSMITTER
WAVEFORM (450Ω/100pF)
MAX3172-04
MAX3172-03
2.5
RISE AND FALL TIMES (µs)
FALL TIME
5V
2.0
T4IN
5V/div
0
1.5
RISE TIME
1.0
T4OUT
5V/div
5V
0
0.5
-5V
RL = 450Ω
0
0
500
1000
1500
2000
2500
10µs/div
3000
LOAD CAPACITANCE (pF)
V.11/V.35 DIFFERENTIAL-MODE
IMPEDANCE vs. COMMON-MODE VOLTAGE
V.11/V.35 DIFFERENTIAL-MODE
IMPEDANCE vs. TEMPERATURE
108
107
106
VCM = +7V
105
VCM = 0
104
103
102
VCM = -7V
101
110
MAX3172-06
109
DIFFERENTIAL-MODE IMPEDANCE (Ω)
MAX3172-05
DIFFERENTIAL-MODE IMPEDANCE (Ω)
110
109
108
107
106
105
104
103
102
101
100
100
-10
0
10
20
30
40
50
TEMPERATURE (°C)
60
70
80
-7
-5
-3
-1
1
3
5
7
COMMON-MODE VOLTAGE (V)
_______________________________________________________________________________________
5
MAX3172/MAX3174
Typical Operating Characteristics
(VCC = +3.3V (see Note 2 in Electrical Characteristics table), TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = +3.3V (see Note 2 in Electrical Characteristics table), TA = +25°C, unless otherwise noted.)
V.11/V.35 DIFFERENTIAL-MODE
IMPEDANCE vs. V+
V.11/V.35 DIFFERENTIAL-MODE
IMPEDANCE vs. V-
104.5
104.0
103.5
103.0
4.4
4.6
4.8
5.0
104.0
103.5
5.2
5.4
-5.4 -5.2 -5.0 -4.8 -4.6 -4.4 -4.2 -4.0 -3.8 -3.6
V- (V)
V.35 COMMON-MODE IMPEDANCE
vs. TEMPERATURE
V.35 COMMON-MODE IMPEDANCE
vs. COMMON-MODE VOLTAGE
152
VCM = -2.0V
151
150
149
148
MAX3172-10
VCM = 0
153
154
COMMON-MODE IMPEDANCE (Ω)
VCM = 2.0V
MAX3172-09
V+ (V)
154
153
152
151
150
149
148
147
10
20
30
40
50
60
70
-2.0 -1.5 -1.0 -0.5
80
0
0.5
1.0
1.5
TEMPERATURE (°C)
COMMON-MODE VOLTAGE (V)
V.35 COMMON-MODE
IMPEDANCE vs. V+
V.35 COMMON-MODE
IMPEDANCE vs. VMAX3172-11
165
160
155
150
145
140
165
2.0
MAX3172-12
0
COMMON-MODE IMPEDANCE (Ω)
-10
160
155
150
145
140
135
135
5.5
5.7
5.9
6.1
V+ (V)
6
MAX3172-08
104.5
103.0
4.2
COMMON-MODE IMPEDANCE (Ω)
105.0
DIFFERENTIAL-MODE IMPEDANCE (Ω)
MAX3172-07
DIFFERENTIAL-MODE IMPEDANCE (Ω)
105.0
COMMON-MODE IMPEDANCE (Ω)
MAX3172/MAX3174
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
6.3
6.5
-6.6
-6.4
-6.2
-6.0
-5.8
-5.6
V- (V)
_______________________________________________________________________________________
-5.4
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
A
A
R1
52Ω
R1
52Ω
OHMMETER
S1 ON
R3
127Ω
S1 ON
R3
127Ω
S2 OFF
OHMMETER
S2 ON
R2
52Ω
R2
52Ω
VCM = ±2V
B
VCM = ±7V OR ±2V
B
Figure 1. V.11 or V.35 Differential Impedance Measurement
T
Figure 2. V.35 Common-Mode Impedance Measurement
T
CL
Figure 3. V.10/V.28 Driver Test Circuit
R
RL
15pF
Figure 4. V.10/V.28 Receiver Test Circuit
_______________________________________________________________________________________
7
MAX3172/MAX3174
Test Circuits
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
MAX3172/MAX3174
Pin Description
8
PIN
NAME
FUNCTION
1
M2
Mode-Select Pin (see Tables 1 and 3 for detailed information)
2
M1
Mode-Select Pin (see Tables 1 and 3 for detailed information)
3
M0
Mode-Select Pin (see Tables 1 and 3 for detailed information)
4
VCC
+3.3V Supply Voltage (±5%). Bypass VCC to GND with a 0.1µF capacitor.
5
R5A
Termination Network 5 Node A
6
R5B
Termination Network 5 Node B
7
T4IN
Transmitter CMOS Input
8
R4OUT
Receiver CMOS Output
9,18, 22
GND
Ground
10
R4B
Termination Network 4 Node B
11
R4A
Termination Network 4 Node A
12
R3C
Termination Network 3 Node C
13
R3B
Termination Network 3 Node B
14
R3A
Termination Network 3 Node A
15
R1A
Termination Network 1 Node A
16
R1B
Termination Network 1 Node B
17
R1C
Termination Network 1 Node C
19
R2C
Termination Network 2 Node C
20
R2B
Termination Network 2 Node B
21
R2A
Termination Network 2 Node A
23
R4INA
24
V-
25
T4OUT
26
V+
27
DCE/DTE
28
INVERT
Inverting Receiver Input
Negative Supply (connect to V- pin of MAX3171/MAX3173). Bypass V- to GND with
a 0.1µF capacitor.
Inverting Transmitter Output
Positive Supply (connect to V+ pin of MAX3171/MAX3173). Bypass V+ to GND with
a 0.1µF capacitor.
DCE/DTE Mode-Select Pin. Logic level LOW selects DTE interface. See Tables 1
and 3 for detailed information.
Mode-Select Pin (inverts functionality of DCE/DTE input for T4/R4). See Tables 1 and
3 for detailed information.
_______________________________________________________________________________________
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
MAX3172/MAX3174
Table 1. Termination Mode Selection
MODE
V.10/RS-423
M2
0
M1
0
M0
0
DCE/DTE
0
INVERT
X
R1
Z
R2
Z
R3
Z
R4
Z
R5
Z
RS-530A
0
0
1
0
X
Z
Z
V.11
V.11
V.11
RS-530
0
1
0
0
X
Z
Z
V.11
V.11
V.11
X.21
0
1
1
0
X
Z
Z
V.11
V.11
V.11
V.35
1
0
0
0
X
V.35
V.35
V.35
V.35
V.35
V.11
RS-449/V.36
1
0
1
0
X
Z
Z
V.11
V.11
V.28/RS-232
1
1
0
0
X
Z
Z
Z
Z
Z
No Cable
1
1
1
0
X
V.11
V.11
V.11
V.11
V.11
V.10/RS-423
0
0
0
1
X
Z
Z
Z
Z
Z
RS-530A
0
0
1
1
X
Z
Z
Z
V.11
V.11
RS-530
0
1
0
1
X
Z
Z
Z
V.11
V.11
X.21
0
1
1
1
X
Z
Z
Z
V.11
V.11
V.35
1
0
0
1
X
V.35
V.35
V.35
V.35
V.35
RS-449/V.36
1
0
1
1
X
Z
Z
Z
V.11
V.11
V.28/RS-232
1
1
0
1
X
Z
Z
Z
Z
Z
No Cable
1
1
1
1
X
V.11
V.11
V.11
V.11
V.11
Detailed Description
The MAX3172/MAX3174 contain five software-selectable
multiprotocol cable termination networks. Each network is
capable of terminating V.11 transceivers (RS-422, RS530, RS-530A, RS-449, V.36, and X.21) with a 100Ω differential load, V.35 transceivers with a T-network load, or
V.28 (RS-232) and V.10 transceivers (RS-423) with an
open circuit load. The MAX3172/MAX3174, along with the
MAX3170 and MAX3171/MAX3173, form a complete
+3.3V software-selectable DTE or DCE interface port supporting V.11/RS-422, RS-530, RS-530A, V.36/RS-449,
V.35, V.28/RS-232, V.10/RS-423, and X.21 serial interfaces.
The MAX3172/MAX3174 also contain a multiprotocol
transceiver that is software-selectable between V.10 and
V.28 operation modes. This transceiver is intended as the
handshake signal I/O in a DCE/DTE port application, and
is designed to use V+ and V- levels generated by the
MAX3171/MAX3173 charge pump. The MAX3172 features 10µs deglitching on the V.10/V.28 receiver input to
allow unterminated operation. The MAX3174 is used in
applications that do not require deglitching on the serial
handshake signals.
No-Cable Mode
The MAX3172/MAX3174 enter no-cable mode when the
mode-select inputs are all HIGH (M0 = M1 = M2 = 1). In
this mode, the driver, receiver, and bias circuitry are disabled, and the supply current drops to less than 200µA.
Table 2. Switch Configuration by Mode
MODE
SW1
SW2
V.35
ON
ON
V.11
ON
OFF
V.28/V.10 (Z)
OFF
OFF
In no-cable mode, all five termination networks are
placed in the V.11 mode of operation (shorting pins R_A
and R_B with a 100Ω resistor). The receiver output enters
a high-impedance state in no-cable mode, allowing this
output line to be shared with other receivers (the receiver
output has an internal pullup resistor to pull the output
HIGH if not driven). Also, in no-cable mode, the transmitter output enters a high-impedance state so that this output can be shared with other devices.
Cable Termination
The MAX3172/MAX3174 software-selectable resistor networks are intended for use with the MAX3170 clock/data
transceiver chip. The termination network is used for the
V.11, V.35, and V.28 transmitters. The MAX3172/
MAX3174 provide the advantage of not having to build
expensive termination networks from resistors and relays,
manually changing termination modules, or building termination networks into custom cables.
Each termination network can be in one of three modes:
V.35, V.11, or high impedance (high-Z) as shown in
Figure 5 (see Table 2). For example, in V.35 mode, all five
_______________________________________________________________________________________
9
MAX3172/MAX3174
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
Table 3. R4/T4 Mode-Select Table
PROTOCOL
M2
M1
M0
DCE/DTE
INVERT
T4
R4
Not Used (Default V.11)
0
0
0
0
0
Z
V.10
RS-530A
0
0
1
0
0
Z
V.10
RS-530
0
1
0
0
0
Z
V.10
X.21
0
1
1
0
0
Z
V.10
V.35
1
0
0
0
0
Z
V.28
RS-449/V.36
1
0
1
0
0
Z
V.10
V.28/RS-232
1
1
0
0
0
Z
V.28
No Cable
1
1
1
0
0
Z
Z
Not Used (Default V.11)
0
0
0
1
0
V.10
Z
RS-530A
0
0
1
1
0
V.10
Z
RS-530
0
1
0
1
0
V.10
Z
X.21
0
1
1
1
0
V.10
Z
V.35
1
0
0
1
0
V.28
Z
RS-449/V.36
1
0
1
1
0
V.10
Z
V.28/RS-232
1
1
0
1
0
V.28
Z
No Cable
1
1
1
1
0
Z
Z
Not Used (Default V.11)
0
0
0
0
1
V.10
Z
RS-530A
0
0
1
0
1
V.10
Z
RS-530
0
1
0
0
1
V.10
Z
X.21
0
1
1
0
1
V.10
Z
V.35
1
0
0
0
1
V.28
Z
RS-449/V.36
1
0
1
0
1
V.10
Z
V.28/RS-232
1
1
0
0
1
V.28
Z
No Cable
1
1
1
0
1
Z
Z
Not Used (Default V.11)
0
0
0
1
1
Z
V.10
RS-530A
0
0
1
1
1
Z
V.10
RS-530
0
1
0
1
1
Z
V.10
X.21
0
1
1
1
1
Z
V.10
V.35
1
0
0
1
1
Z
V.28
RS-449/V.36
1
0
1
1
1
Z
V.10
V.28/RS-232
1
1
0
1
1
Z
V.28
No Cable
1
1
1
1
1
Z
Z
networks are configured to provide 100Ω differential
impedance and 150Ω common-mode impedance to terminate the MAX3170 V.35 transmitter outputs and receiver inputs.
Termination Mode Selection
The mode-select pins M0, M1, M2, and DCE/DTE control
the state of the five termination networks (Table 1). The
mode-select table of the MAX3172/MAX3174 is compatible with the MAX3170 mode-select table so that the M0,
10
M1, M2, and DCE/DTE pins can be connected to the corresponding pins on the MAX3170. For example, M2 = 1,
M1 = 0, M0 = 0 corresponds to V.35 mode for both the
MAX3172/MAX3174 and the MAX3170 clock/data transceiver chip.
R4/T4 Mode Selection
The MAX3172/MAX3174 include a transceiver for use in
applications requiring an extra serial handshake signal
(for example, local loopback). The transceiver can be
______________________________________________________________________________________
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
MAX3172/MAX3174
*NODE C IS PROVIDED IN NETWORKS 1,2,3.
A
A
A
R1
52Ω
R1
52Ω
R1
52Ω
C*
C*
S1 ON
C*
S1 OFF
S1 ON
R3
127Ω
R3
127Ω
S2 OFF
R3
127Ω
S2 ON
R2
52Ω
S2 OFF
R2
52Ω
B
R2
52Ω
B
B
V.11 MODE
V.35 MODE
HIGH-Z MODE
Figure 5. MAX3172/MAX3174 Termination Network Configurations
BALANCED
INTERCONNECTING
CABLE
GENERATOR
LOAD
CABLE
RECEIVER
TERMINATION
A′
A
100Ω
MIN
B
B′
C
C′
Figure 6. Typical V.11 Interface
configured for V.10 or V.28 operation as a driver or
receiver (Table 3). This mode-selection table is compatible for use with the MAX3170 (clock/data transceiver)
and the MAX3171/MAX3173 (control transceiver). For
example, if X.21 mode is selected in DCE mode (M2 = 0,
M1 = 1, M0 = 1, and DCE/DTE = 1), the MAX3170,
MAX3171/MAX3173, and MAX3172/MAX3174 transceivers will all be placed in X.21 DCE mode.
threshold is between +25mV and +250mV. If the V.10
receiver input voltage is less than +25mV, R4OUT is
logic HIGH. If the V.10 receiver input is greater than
+250mV, R4OUT is logic LOW.
The V.28 receiver threshold is between +0.8V and
+2.0V. If the V.28 receiver input voltage is less than
+0.8V, R4OUT is logic HIGH. If the receiver input is
greater than +2.0V, R4OUT is logic LOW. If the driving
transmitter is disabled or disconnected, the receiver’s
input voltage is pulled to zero by its internal termination.
With the receiver thresholds of the MAX3172/MAX3174,
this results in a logic HIGH.
Applications Information
Fail-Safe
Older multiprotocol cable termination implementations
have been constructed using expensive relays with discrete resistors, custom cables with built-in termination,
or complex circuit board configurations to route signals
to the correct termination. The MAX3172/MAX3174 provide a simple solution to this termination problem. All
required termination configurations are software selectable using four mode-control input pins (M2, M1, M0,
and DCE/DTE).
The MAX3172/MAX3174 guarantee a logic HIGH
receiver output when the receiver input is shorted to
GND or when it is connected to a terminated transmission line with the driver disabled. The V.10 receiver
For high-speed data transmission, the V.11 specification recommends terminating the cable at the receiver
V.11 Termination
______________________________________________________________________________________
11
MAX3172/MAX3174
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
A′
A
MAX3170
R5
30kΩ
R1
52Ω
R8
5kΩ
MAX3172
MAX3174
R6
10kΩ
RECEIVER
S3
S1
R3
127Ω
S2
R7
10kΩ
R2
52Ω
B′
R4
30kΩ
B
C′
GND
Figure 7. V.11 Termination and Internal Resistance Networks
BALANCED
INTERCONNECTING
CABLE
GENERATOR
A
50Ω
LOAD
A′
125Ω
CABLE
TERMINATION
125Ω
50Ω
RECEIVER
50Ω
50Ω
B
B′
C
C′
Figure 8. Typical V.35 Interface
with a minimum of a 100Ω resistor (Figure 6). This resistor, although not required, prevents reflections from
corrupting transmitted data.
In Figure 7, the MAX3172/MAX3174 are used to terminate the V.11 receiver. Internal to the MAX3172/
MAX3174, S1 is closed and S2 is open to present a
104Ω typical differential resistance and high-Z common-mode impedance. S3 opens to disable the
MAX3170’s internal V.28 termination.
The V.11 specification allows for signals with commonmode variations of ±7V with differential signal amplitudes from 2V to 6V. Also, data rates may be as high as
12
10Mbps. The MAX3172/MAX3174 maintain steady termination impedance between 100Ω and 110Ω over
these conditions.
V.35 Termination
Figure 8 shows a 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 8). The V.35 driver generates a current output
(typically ±11mA) that develops an output voltage
between 440mV and 660mV across the load termination networks.
______________________________________________________________________________________
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
MAX3172/MAX3174
A′
A
MAX3170
R5
30kΩ
R1
52Ω
R8
5kΩ
MAX3172
MAX3174
R6
10kΩ
RECEIVER
S3
S1
R3
127Ω
S2
R7
10kΩ
R2
52Ω
B′
R4
30kΩ
B
C′
GND
Figure 9. V.35 Termination and Internal Resistance Networks
A
DRIVER
The V.35 specification allows for ±4V of ground difference between the V.35 generator and V.35 load. The
V.35 data rates may be as high as 10Mbps. The
MAX3172/MAX3174 maintain correct terminal impedances over these conditions.
R1
52Ω
MAX3172
MAX3174
S1
R3
127Ω
V.35 EMI Reduction
S2
R2
52Ω
R_C
C1
100pF
tion resistor, internal to the MAX3170, is disabled by
opening S3 to avoid interference with the T-network
impedance.
B
C(GND)
Figure 10. V.35 Driver
In Figure 9, the MAX3172/MAX3174 are used to implement the resistive T-network that is needed to properly
terminate the V.35 driver and receiver. Internal to the
MAX3172/MAX3174, S1 and S2 are closed to connect
the T-network resistors to the circuit. The V.28 termina-
For applications where EMI reduction is especially
important, the MAX3172/MAX3174 termination networks provide a pin for shunting common-mode driver
currents to GND (Figure 10). Mismatches between A
and B driver output propagation delays create a common-mode disturbance on the cable. This commonmode energy can be shunted to GND by placing a
100pF capacitor (C1 to GND) from the center point of
the T-network termination (R1C, R2C, and R3C).
V.28 Termination
Most industry-standard V.28 receivers (including the
MAX3170) do not require external termination because
the receiver includes an internal 5kΩ termination resistor. When the MAX3172/MAX3174 are placed in V.28
mode, all five of the termination networks are placed in
a high-Z mode. In high-Z mode, the MAX3172/
MAX3174 termination networks will not interfere with the
MAX3170's internal 5kΩ termination.
______________________________________________________________________________________
13
MAX3172/MAX3174
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
A′
A
MAX3170
R5
30kΩ
R1
52Ω
R8
5kΩ
MAX3172
MAX3174
R6
10kΩ
RECEIVER
S3
S1
R3
127Ω
S2
R7
10kΩ
R2
52Ω
B′
R4
30kΩ
B
C′
GND
Figure 11. V.28 Termination and Internal Resistance Networks
GENERATOR
UNBALANCED
INTERCONNECTING
CABLE
LOAD
CABLE
TERMINATION
A
A′
C
C′
RECEIVER
V.10 Interface
Figure 12. Typical V.28 and V.10 Interface
IZ
-10V
3.25mA
-3V
VZ
+10V
+3V
-3.25mA
Figure 13. V.10 Receiver Input Impedance
In Figure 11, the MAX3170 and MAX3172/MAX3174 are
placed in V.28 mode. Switches S1 and S2 are opened
on the MAX3172/MAX3174 to place the network in highZ mode. Switch S3 is closed on the MAX3170 to enable
the 5kΩ terminating resistor.
V.28 Interface
The V.28 interface is an unbalanced single-ended interface (Figure 12). The V.28 driver generates a minimum
of ±5V across the load impedance between A' and C'.
14
The V.28 receiver specification calls for input trip points
at ±3V. To aid in rejecting system noise, the MAX3170
V.28 receiver has a typical hysteresis of 0.5V. Also, the
MAX3172/MAX3174 have more tightly specified input
trip points to guarantee fail-safe operation (see FailSafe).
The MAX3172/MAX3174 V.28 receiver provides an
internal 5kΩ termination resistance.
The V.10 interface (Figure 12) is an unbalanced singleended interface capable of driving a 450Ω load. The
V.10 driver generates a minimum voltage of ±4V
(VODO) across A' and C' when unloaded and a minimum voltage of ±0.9 ✕ VODO when loaded with 450Ω.
The V.10 receiver input trip threshold is defined
between +300mV and -300mV with input impedance
characteristics shown in Figure 13.
The MAX3172/MAX3174 V.10 mode receiver has a
threshold between +25mV and +250mV to ensure that
the receiver has proper fail-safe operation (see FailSafe). To aid in rejecting system noise, the MAX3172/
MAX3174 V.10 receiver has a typical hysteresis of
15mV. Switch S3 in Figure 14 is open in V.10 mode to
disable the 5kΩ V.28 termination at the receiver input.
Receiver Glitch Rejection
To allow operation in an unterminated or otherwise
noisy system, the MAX3172 features 10µs of receiver
input glitch rejection. The glitch-rejection circuitry
blocks the reception of high-frequency noise with a bit
period less than 5µs while receiving low-frequency signals with a bit period greater than 15µs, allowing glitchfree operation in unterminated systems at up to 64kbps.
______________________________________________________________________________________
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
A
MAX3172
MAX3174
R5
30kΩ
R8
5kΩ
R6
10kΩ
Complete Multiprotocol X.21 Interface
RECEIVER
S3
R7
10kΩ
R4
30kΩ
A complete DTE-to-DCE interface operating in X.21
mode is shown in Figure 16. The MAX3172/MAX3174 terminate the V.11 clock and data signals, and its transceiver carries the local loopback (LL) signal. The MAX3170
carries the clock and data signals, and the
MAX3171/MAX3173 carry the control signals. The control
signals generally do not require external termination.
Compliance Testing
A European Standard EN45001 test report is available
for the MAX3170–MAX3174 chipset. A copy of the test
report is available from Maxim upon request.
C′
GND
Figure 14. V.10 Internal Resistance Networks
The MAX3174 does not have this glitch rejection and
can be operated at frequencies up to 240kbps if properly terminated.
DCE vs. DTE Operation
Figure 15 illustrates a DCE or DTE controller-selectable
interface. The DCE/DTE input switches the MAX3172/
MAX3174s’ mode of operation. Logic high selects DCE,
which enables driver 4 on the MAX3172/MAX3174
(INVERT = 0), driver 3 on the MAX3171/MAX3173, and
driver 3 on the MAX3170. A logic low selects DTE,
which enables receiver 4 on the MAX3172/MAX3174
(INVERT = 0), receiver 1 on the MAX3171/MAX3173,
and receiver 1 on the MAX3170.
______________________________________________________________________________________
15
MAX3172/MAX3174
A′
This application requires only one DB-25 connector.
See Figure 15 for complete signal routing in DCE and
DTE modes. For example, driver 4 routes the LL(DCE)
signal to pin 18 in DCE mode, while in DTE mode,
receiver 4 routes pin 18 to the LL(DTE) signal.
CTS(DTE)
RTS(DCE)
DSR(DTE)
DTR(DCE)
RXD(DTE)
TXD(DCE)
LL(DTE)
RXC(DTE)
LL(DCE)
SCTE(DCE)
DTR(DTE)
DSR(DCE)
RTS(DTE)
DCD(DTE)
CTS(DCE)
DCD(DCE)
SCTE(DTE)
RXC(DCE)
TXC(DTE)
TXD(DTE)
TXC(DCE)
RXD(DCE)
MAX3171
MAX3173
R3
R2
R1
D3
D2
D1
M0
M1
M2
DCE/DTE
MAX3172
MAX3174
R4
R3
R2
16 3
9 17
R1
D3
D2
D1
D4
MAX3170
M0
M1
M2
DCE/DTE
MAX3172/MAX3174
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
Figure 15. Multiprotocol DCE/DTE Port
16
______________________________________________________________________________________
TXD B
TXD A
RXD B
RXD A
TXC B
TXC A
TXC B
TXC A
RXC B SCTE B
RXC A SCTE A
RXD B
RXD A
RXC B
RXC A
DB-25 CONNECTOR
12 15 11 24 14 2
TXD B
TXD A
SCTE B
SCTE A
SG
LL A
7 18
LL A
1
SHIELD
RTS B
RTS A
CTS B
CTS A
DTR B
DTR A
DCD B
DCD A
23 20 19 4
DSR B
DSR A
DSR B
DSR A
DCD B
DCD A
22 6
DTR B
DTR A
10 8
DCE
RTS B
RTS A
13 5
DTE
CTS B
CTS A
M0
M1
M2
DCE/DTE
M0 M1 M2 DCE/DTE
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
SERIAL
CONTROLLER
MAX3170
DCE
MAX3172
MAX3174
MAX3172
MAX3174
TXD
D1
TXD
SCTE
D2
SCTE
103Ω
103Ω
D3
TXC
R1
RXC
R2
RXD
R3
MAX3170
SERIAL
CONTROLLER
R3
TXD
R2
SCTE
R1
103Ω
103Ω
103Ω
D4
LL
MAX3172/MAX3174
DTE
TXC
D3
TXC
RXC
D2
RXC
RXD
LL
D1
RXD
R4
R4
LL
D4
MAX3171
MAX3173
MAX3171
MAX3173
RTS
D1
RTS
R3
RTS
DTR
D2
DTR
R2
DTR
D3
R1
DCD
R1
DCD
D3
DCD
DSR
R2
DSR
D2
DSR
CTS
R3
CTS
D1
CTS
Figure 16. DCE-TO-DTE X.21 Interface
______________________________________________________________________________________
17
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
MAX3172/MAX3174
Pin Configuration
Chip Information
TRANSISTOR COUNT: 2506
TOP VIEW
M2 1
28 INVERT
M1 2
27 DCE/DTE
M0 3
26 V+
VCC 4
25 T4OUT
R5A 5
R5B 6
24 V-
MAX3172
MAX3174
23 R4INA
T4IN 7
22 GND
R4OUT 8
21 R2A
GND 9
20 R2B
R4B 10
19 R2C
R4A 11
18 GND
R3C 12
17 R1C
R3B 13
16 R1B
R3A 14
15 R1A
28 SSOP
18
______________________________________________________________________________________
+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers
SSOP.EPS
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 19
© 2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX3172/MAX3174
Package Information