MAXIM MAX13450EAUD+

19-5254; Rev 0; 4/10
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
The MAX13450E/MAX13451E are half-duplex and fullduplex RS-485/RS-422 transceivers. These devices feature internal 100I and 120I termination resistors. The
resistor values are pin selectable. A logic supply input
allows interfacing to logic levels down to +1.8V.
The MAX13450E/MAX13451E feature strong drivers
specified to drive low-impedance lines found when a
fully loaded bus, based on today’s 100I characteristic
impedance cable, is doubly terminated. Both devices
allow slew-rate limiting of the driver output to reduce EMI
and reflections for data rates up to 500kbps.
The MAX13451E has a FAULT alarm indication output to
signal to the system that an error condition exists in the
driver. The MAX13451E also features a logic inversion
function. The logic inversion allows phase reversal of the
A-B signals in case these are inadvertently connected
wrongly.
The MAX13450E/MAX13451E have 1/8-unit load receiver
input impedance, allowing up to 256 transceivers on the
bus. All driver outputs are protected to Q30kV ESD using
the Human Body Model (HBM).
The MAX13450E/MAX13451E are available in a 14-pin
TSSOP package and operate over the automotive -40NC
to +125NC temperature range.
Applications
Features
S 100I/120I Pin-Selectable Internal Termination
Resistors
S Driver Drives 100I Double Termination
S 20Mbps (max) Data Rate
S Pin-Selectable Slew-Rate Limiting
S Logic Supply Input Allows Interfacing Down to 1.8V
S Driver Fault-Indication Output (MAX13451E)
S Inverting of A, B Line Polarity (MAX13451E)
S High-Impedance Driver Output/Receiver Input
When VCC Supply is Removed
S Hot-Swap Input Structure on DE, RE, and TERM
S Extended ESD Protection
±30kV Human Body Model
±15kV Air Gap Discharge per IEC 61000-4-2
±7kV Contact Discharge per IEC 61000-4-2
S 1/8-Unit Load Allows Up to 256 Transceivers on
the Bus
S Thermal and Overcurrent Protected
S Fail-Safe Receivers
S +4.5V to +5.5V Supply Voltage Range
Functional Diagram (MAX13451E)
VL
Industrial Control Systems
Portable Industrial Equipment
SRL
Motor Control
MAX13451E
INV
Security Networks
D
DI
Medical Networks
Ordering Information/
Selector Guide
FAULT
DE
B
TERM
HALF/FULL
DUPLEX
PIN-PACKAGE
MAX13450EAUD+
Full
14 TSSOP-EP*
MAX13451EAUD+
Half
14 TSSOP-EP*
PART
VCC
Note: All devices are specified over the -40°C to +125°C
operating temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
LOGIC
LOGIC-LEVEL
TRANSLATION
RE
A
RO
TERM100
GND
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX13450E/MAX13451E
General Description
MAX13450E/MAX13451E
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND.)
VCC, VL . ..................................................................-0.3V to +6V
DE, RE, DI, RO, TERM, TERM100, SRL . .... -0.3V to (VL + 0.3V)
INV, FAULT ................................................. -0.3V to (VL + 0.3V)
A, B, Z, Y...................................................................-8V to +13V
A to B (High-Z State) . ........................................................ +14V
B to A (High-Z State) . ........................................................ +14V
Short-Circuit Duration (RO, Y, Z) to GND................. Continuous
Continuous Power Dissipation (TA = +70NC)
14-Pin TSSOP (derate 25.6mW/NC above +70NC)......2051mW
Package Junction-to-Ambient Thermal
Resistance (BJA) (Note 1) ............................................39NC/W
Package Junction-to-Case Thermal
Resistance (BJC) (Note 1)...............................................3NC/W
Operating Temperature Range . ...................... -40NC to +125NC
Storage Temperature Range ........................... -65NC to +150NC
Junction Temperature .....................................................+150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow).......................................+260NC
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
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 = +4.5V to +5.5V, VL = +1.62V to 4.2V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V,
VL = +1.8V, and TA = +25NC.) (Note 2)
PARAMETER
Supply Voltage
Logic Supply Voltage
Supply Current
Logic Supply Current
Shutdown Current
SYMBOL
CONDITIONS
MIN
VCC
4.5
VL
1.62
ICC
IL
ISHDN
TYP
1.8
MAX
UNITS
5.5
V
4.2
V
DE = RE = high, TERM = high, no load
6
DE = RE = low, TERM = low, no load
12
Current into VL, no load on RO, device not
switching, DE = RE = high
2
FA
Current into VCC, DE = low, RE = TERM =
high
30
FA
Current into VCC, DE = low, RE = high,
TERM = low
8
mA
mA
DRIVER
Differential Driver Output
Change in Magnitude of
Differential Output Voltage
VOD
RDIFF = 100I, Figure 1 (Note 3)
2.0
VCC
RDIFF = 46I, Figure 1 (Note 3)
1.5
VCC
DVOD
RDIFF = 100I or 46I, Figure 1 (Note 3)
VOC
RDIFF = 100I or 46I, Figure 1 (Note 3)
Change In Magnitude of
Common-Mode Voltage
DVOC
RDIFF = 100I or 46I, Figure 1 (Note 3)
Driver Short-Circuit Output
Current
IOSD
0V P VOUT P +12V
-7V P VOUT P 0V
-250
Driver Short-Circuit Foldback
Output Current
IOSDF
(VCC - 1V) P VOUT P +12V
+15
Driver Common-Mode Output
Voltage
VCC/2
0.2
V
3
V
0.2
V
+280
-7V P VOUT P 0V
2 _______________________________________________________________________________________
V
-15
mA
mA
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
(VCC = +4.5V to +5.5V, VL = +1.62V to 4.2V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V,
VL = +1.8V, and TA = +25NC.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RECEIVER
Input Current (A and B)
IA, B
DE = RE = GND;
TERM = VL; VCC = GND
or 5.5V
Receiver Differential Threshold
Voltage
VTH
-7V P VCM P +12V,
DE = RE = GND;
TERM = VL; VCC = GND
Receiver Input Hysteresis
DVTH
VA or VB = +12V
125
VA or VB = -7V
-100
VA or VB = +12V
-200
VA + VB = 0V
FA
-50
15
mV
mV
LOGIC INTERFACE
Input High Voltage
VIH
DI, DE, RE, TERM, SRL, TERM100, INV
Input Low Voltage
VIL
DI, DE, RE, TERM, SRL, TERM100, INV
Input Current
IIN
2/3 x VL
-1
Receiver Output High Voltage
VROH
DI, DE, RE, TERM, TERM100, SRL, INV
IOUT = -1mA
Receiver Output Low Voltage
VROL
IOUT = +1mA
Three-State Output Current at
Receiver
IOZR
0V P VRO P VL
-1
Receiver Output Short-Circuit
Current
IOSR
0V P VRO P VL
Q1
Fault Output High Voltage
(MAX13451E)
VFAULTH
Fault condition, IOUT = -1mA
Fault Output Low Voltage
(MAX13451E)
VFAULTL
Nonfault condition; IOUT = +1mA
V
1/3 x VL
V
+1
FA
VL - 0.6
V
+0.01
0.4
V
+1
FA
Q80
mA
VL - 0.6
V
0.4
V
TERMINATION RESISTOR
100I Termination Resistor
R100
TERM = low, TERM100 = high
85
100
115
I
120I Termination Resistor
R120
TERM = low, TERM100 = low
101
120
139
I
Single-Ended Input Capacitance
vs. GND
CIN
f = 1MHz (MAX13451E only)
40
pF
ESD PROTECTION
ESD Protection (A, B, Y, Z)
ESD Protection (All Other Pins)
Human Body Model
Q30
IEC 61000-4-2 Air Gap Discharge
Q15
IEC 61000-4-2 Contact Discharge
Q7
Human Body Model
Q2
kV
_______________________________________________________________________________________ 3
MAX13450E/MAX13451E
ELECTRICAL CHARACTERISTICS (continued)
MAX13450E/MAX13451E
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
SWITCHING CHARACTERISTICS—SRL = HIGH
(VCC = +4.5V to +5.5V, VL = +1.62V to 4.2V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V,
VL = +1.8V and TA = +25NC.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Driver Propagation Delay
Differential Driver Output Skew
|tDPLH - tDPHL|
Driver Differential Output Rise or
Fall Time
Maximum Data Rate
tDPLH
tDPHL
tDSKEW
tHL
tLH
800
RDIFF = 54I, CL = 50pF, Figures 2 and 3
800
100
RDIFF = 54I, CL = 50pF, Figure 3
RDIFF = 54I, CL = 50pF, Figures 2 and 3
DRMAX
100
600
100
600
500
ns
ns
ns
kbps
Driver Enable from Shutdown to
Output High
S2 closed, RL = 500I, CL = 100pF,
tDZH(SHDN)
Figures 4 and 5
4500
ns
Driver Enable from Shutdown to
Output Low
tDZL(SHDN)
S1 closed, RL = 500I, CL = 100pF,
Figures 4 and 5
5200
ns
Driver Disable Delay
tDLZ, tDHZ
Figures 4 and 5
100
ns
Driver Enable Delay
tDZL, tDZH
Figures 4 and 5
2500
ns
CL = 15pF, |VID| R 2.0V; tLH, tHL P 15ns,
Figures 6 and 7
200
RECEIVER
Receiver Propagation Delay
tRPLH
tRPHL
Receiver Output Skew
tRSKEW
Maximum Data Rate
DRMAX
200
CL = 15pF, Figures 6 and 7
30
500
ns
ns
kbps
Receiver Enable to Output High
tRZH
S2 closed, CL = 100pF, RL = 500I,
Figures 8 and 9
50
ns
Receiver Enable to Output Low
tRZL
S1 closed, CL = 100pF, RL = 500I,
Figures 8 and 9
50
ns
Receiver Disable from High
tRHZ
Figures 8 and 9
50
ns
Receiver Disable from Low
tRLZ
Figures 8 and 9
50
ns
Receiver Enable from Shutdown
to Output High
tRZH(SHDN) Figures 8 and 9
5000
ns
Receiver Enable from Shutdown
to Output Low
tRZL(SHDN) Figures 8 and 9
5000
ns
TERMINATION RESISTOR
Turn-Off Time
tRTZ
Figure 10
120
Fs
Turn-On Time
tRTEN
Figure 10
1
Fs
4 _______________________________________________________________________________________
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
(VCC = +4.5V to +5.5V, VL = +1.62V to 4.2V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V,
VL = +1.8V, and TA = +25NC.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Driver Propagation Delay
tDPLH
tDPHL
50
RDIFF = 54I, CL = 50pF, Figures 2 and 3
50
ns
Differential Driver Output Skew
|tDPLH - tDPHL|
tDSKEW
RDIFF = 54I, CL = 50pF, Figure 3
6
ns
Driver Differential Output Rise or
Fall Time
tHL, tLH
RDIFF = 54I, CL = 50pF, Figures 2 and 3
15
ns
Maximum Data Rate
DRMAX
20
Mbps
Driver Enable from Shutdown to
Output High
S2 closed, RL = 500I, CL = 100pF,
tDZH(SHDN)
Figures 4 and 5
2000
ns
Driver Enable from Shutdown to
Output Low
tDZL(SHDN)
S1 closed, RL = 500I, CL = 100pF,
Figures 4 and 5
2000
ns
Driver Disable Delay
tDLZ, tDHZ
Figures 4 and 5
100
ns
Driver Enable Delay
tDZL, tDZH
Figures 4 and 5
100
ns
CL = 15pF, |VID| R 2.0V; tLH, tHL P 15ns,
Figures 6 and 7
50
RECEIVER
Receiver Propagation Delay
tRPLH
tRPHL
Receiver Output Skew
tRSKEW
Maximum Data Rate
DRMAX
50
CL = 15pF, Figures 6 and 7
6
20
ns
ns
Mbps
Receiver Enable to Output High
tRZH
S2 closed, CL = 100pF, RL = 500I,
Figures 8 and 9
50
ns
Receiver Enable to Output Low
tRZL
S1 closed, CL = 100pF, RL = 500I,
Figures 8 and 9
50
ns
Receiver Disable Time from High
tRHZ
Figures 8 and 9
50
ns
Receiver Disable Time from Low
tRLZ
Figures 8 and 9
50
ns
Receiver Enable from Shutdown
to Output High
tRZH(SHDN) Figures 8 and 9
2000
ns
Receiver Enable from Shutdown
to Output Low
tRZL(SHDN) Figures 8 and 9
2000
ns
TERMINATION RESISTOR
Turn-Off Time
tRTZ
Figure 10
120
Fs
Turn-On Time
tRTEN
Figure 10
1
Fs
Note 2: All devices are 100% production tested at TA = +25°C. Limits over temperature are guaranteed by design.
Note 3: Termination resistance is disabled (TERM = high).
_______________________________________________________________________________________ 5
MAX13450E/MAX13451E
SWITCHING CHARACTERISTICS—SRL = LOW
Typical Operating Characteristics
(VCC = +5V, VL = +1.8V, TA = +25NC, unless otherwise noted.)
SHUTDOWN CURRENT
vs. TEMPERATURE
RL = 100Ω
30
20
6
5
4
3
1
10
2
1
0
-40 -25 -10 5 20 35 50 65 80 95 110 125
100
0
10
20
30
40
50
60
TEMPERATURE (°C)
OUTPUT CURRENT (mA)
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
RECEIVER PROPAGATION DELAY
vs. TEMPERATURE
1.6
1.4
1.2
IOUT = 1mA
0.4
0.3
0.2
0.1
100
RECEIVER PROPAGATION DELAY (ns)
1.8
0.5
RECEIVER OUTPUT LOW VOLTAGE (V)
IOUT = 1mA
MAX13450E/51E toc05
DATA RATE (Mbps)
MAX13450E/51E toc04
2.0
3
SINK
0
0
0.1
SOURCE
4
1
NO LOAD
MAX13450E/51E toc03
7
2
10
0
1.0
INV = HIGH
80
60
70
INV = LOW
40
20
0
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
DRIVER DIFFERENTIAL OUTPUT CURRENT
vs. DIFFERENTIAL OUTPUT VOLTAGE
TRANSMITTER OUTPUT CURRENT
vs. TRANSMITTER OUTPUT HIGH VOLTAGE
TRANSMITTER OUTPUT CURRENT
vs. TRANSMITTER OUTPUT LOW VOLTAGE
60
40
20
100
80
60
40
20
0
0
0
1
2
3
4
DRIVER DIFFERENTIAL OUTPUT VOLTAGE (V)
5
200
MAX13450E/51E toc09
80
120
TRANSMITTER OUTPUT CURRENT (mA)
MAX13450E/51E toc07
100
TRANSMITTER OUTPUT CURRENT (mA)
RECEIVER OUTPUT HIGH VOLTAGE (V)
8
5
MAX13450E/51E toc06
40
MAX13450E/51E toc02
RL = 54Ω
50
9
MAX13450E/51E toc08
SUPPLY CURRENT (mA)
60
10
SHUTDOWN CURRENT (µA)
MAX13450E/51E toc01
70
RECEIVER OUTPUT VOLTAGE
vs. OUTPUT CURRENT
RECEIVER OUTPUT VOLTAGE (V)
SUPPLY CURRENT
vs. DATA RATE
DRIVER DIFFERENTIAL OUTPUT CURRENT (mA)
MAX13450E/MAX13451E
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
180
160
140
120
100
80
60
40
20
0
-7
-2
3
TRANSMITTER OUTPUT HIGH VOLTAGE (V)
-3
2
7
TRANSMITTER OUTPUT LOW VOLTAGE (V)
6 _______________________________________________________________________________________
12
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
RDIFF = 54Ω
3
2
100
80
-10
R100 MAGNITUDE
60
R100 PHASE
-20
40
1
20
0
-30
0
-40 -25 -10 5 20 35 50 65 80 95 110 125
0.1
10
100
FREQUENCY (MHz)
120Ω TERMINATION RESISTOR
vs. FREQUENCY
TERMINATION RESISTANCE
vs. TEMPERATURE
0
120
80
60
R120 PHASE
-20
40
20
-30
0
0.1
1
10
100
120
120Ω RESISTOR
110
100
100Ω RESISTOR
90
80
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
FREQUENCY (MHz)
DRIVER PROPAGATION DELAY (250kbps)
(MAX13451E)
DRIVER ENABLE TIME FROM SHUTDOWN
(MAX13451E)
MAX13450E/51E toc14
SRL = HIGH
DE = HIGH
RE = HIGH
PHASE (DEGREE)
-10
R120 MAGNITUDE
TERMINATION RESISTANCE (Ω)
130
MAX13450E/51E toc13
MAX13450E/51E toc12
100
1
TEMPERATURE (°C)
140
MAGNITUDE (Ω)
0
120
MAGNITUDE (Ω)
4
MAX13450E/51E toc11
140
MAX13450E/51E toc10
5
100Ω TERMINATION RESISTOR
vs. FREQUENCY
PHASE (DEGREE)
DRIVER DIFFERENTIAL OUTPUT VOLTAGE (V)
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
MAX13450E/51E toc15
DE
2V/div
DI
1V/div
A
2V/div
A
1V/div
B
1V/div
1µs/div
SRL = LOW
RE = HIGH
B
2V/div
200ns/div
_______________________________________________________________________________________ 7
MAX13450E/MAX13451E
Typical Operating Characteristics (continued)
(VCC = +5V, VL = +1.8V, TA = +25NC, unless otherwise noted.)
MAX13450E/MAX13451E
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
Test Circuits and Waveforms
A/Y
VL
RDIFF
DE
2
A
DI
VOD
VID
CL
RDIFF
B
RDIFF
VOC
2
B/Z
Figure 1. Driver DC Test Load
Figure 2. Driver Timing Test Circuit
f = 1MHz, tLH ≤ 3ns, tHL ≤ 3ns
VL
DI
VL/2
VL/2
0V
1/2 VO
tDPHL
tDPLH
B
A
1/2 VO
VO
VO
VDD
90%
90%
0V
10%
10%
-VO
tHL
tLH
tDSKEW = |tDPLH - tDPHL|
Figure 3. Driver Propagation Delays
8 _______________________________________________________________________________________
CL
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
VL
DE
VL/2
VL/2
0V
tDLZ
tDZL(SHDN),tDZL
VCC
(VCC + VOL)/2
A/Y, B/Z
VOL
VOL + 0.25V
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
VOH
VOH/2
A/Y, B/Z
VOH - 0.25V
0V
tDZH(SHDN),tDZH
tDHZ
Figure 4. Driver Enable and Disable Times
500Ω
OUTPUT
UNDER TEST
S1
VCC
B
CL
RECEIVER
OUTPUT
R
VID
ATE
A
S2
Figure 5. Driver-Enable and Disable-Timing Test Load
Figure 6. Receiver Propagation Delay Test Circuit
f = 1MHz, tLH ≤ 3ns, tHL ≤ 3ns
A
1V
B
-1V
tRPHL
tRPLH
VROH
RO
VL/2
VROL
VL/2
tRSKEW = |tRPHL - tRPLH|
Figure 7. Receiver Propagation Delays
_______________________________________________________________________________________ 9
MAX13450E/MAX13451E
Test Circuits and Waveforms (continued)
MAX13450E/MAX13451E
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
Test Circuits and Waveforms (continued)
VL
RE
VL/2
VL/2
0V
tRZL(SHDN), tRZL
tRHZ
VL
RO
(VL + VROL)/2
VROL
ROH + 0.25V
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
VROH
VROH/2
RO
ROH - 0.25V
0V
tRZH(SHDN), tRZH
DI = 0V
tRHZ
Figure 8. Receiver Enable and Disable Times
VCC
S1
500Ω
RO
CL
S2
Figure 9. Receiver Enable and Disable Times
IA = VAB/RD
VAB = VA - VB
RD = R100 OR R200
A
RO
RECEIVER
TERM
VL
VL/2
TERM
0V
B
tREN
IA
tREN
90%
10%
Figure 10. Termination Resistor Turn-On/-Off Times
10 �������������������������������������������������������������������������������������
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
TOP VIEW
TOP VIEW
+
+
DE
1
14
SRL
DE
1
14
SRL
RE
2
13
TERM100
RE
2
13
TERM100
DI
3
12
Z
DI
3
12
B
VCC
4
11
GND
VCC
4
11
GND
TERM
5
10
Y
TERM
5
10
A
VL
6
9
B
VL
6
9
FAULT
RO
7
8
A
RO
7
8
INV
MAX13450E
EP
TSSOP
MAX13451E
EP
TSSOP
Pin Description
PIN
NAME
FUNCTION
1
DE
Driver-Output Enable. Drive DE low to put the driver output in three-state. Drive DE
high to enable the driver. DE is referenced to VL.
2
2
RE
Receiver-Output Enable. Drive RE low to enable the RO. Drive RE high to disable
the RO output and put the RO output in a high-impedance state. RE is referenced
to VL.
3
3
DI
Driver Input. Drive DI low to force the noninverting output low and the inverting
output high. Drive DI high to force the noninverting output high and inverting output low. DI is referenced to VL.
4
4
VCC
5
5
TERM
6
6
VL
Logic Supply Voltage. Bypass VL to GND with a 0.1FF ceramic capacitor placed
as close as possible to the device.
7
—
RO
Receiver Output. When receiver is enabled and VA - VB R -50mV, RO is high. If
VA - VB P -200mV, RO is low. RO is referenced to VL.
—
7
RO
Receiver Output. When INV is low, receiver is enabled and VA - VB R -50mV, RO is
high. If VA - VB P -200mV, RO is low. When INV is high, receiver is enabled and
VA - VB R -50mV, RO is low. If VA - VB P -200mV, RO is high. RO is referenced to VL.
8
—
A
Noninverting Receiver Input
—
10
A
If INV is low, A is a noninverting receiver input and a noninverting driver output. If
INV is high, A is an inverting receiver input and an inverting driver output.
9
—
B
Inverting Receiver Input
—
12
B
If INV is low, B is an inverting receiver input and an inverting driver output. If INV
is high, B is a noninverting receiver input and a noninverting driver output.
MAX13450E
MAX13451E
1
Power-Supply Voltage. Bypass VCC to GND with a 0.1FF ceramic capacitor
placed as close as possible to the device.
Active-Low Termination Resistor Enable. Drive TERM low to enable the internal termination resistor. TERM is referenced to VL.
______________________________________________________________________________________ 11
MAX13450E/MAX13451E
Pin Configurations
MAX13450E/MAX13451E
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
Pin Description (continued)
PIN
MAX13450E
MAX13451E
NAME
FUNCTION
10
—
Y
11
11
GND
Noninverting Driver Output
12
—
Z
13
13
TERM100
Termination Resistor Value Selection Input. Drive TERM100 low to select a 120I
termination and high to select a 100I termination. The TERM100 input is referenced to VL.
14
14
SRL
Slew-Rate Limiting-Enable Input. Drive SRL high to enable slew-rate limiting and
low to disable slew-rate limiting. The SRL input is referenced to VL.
—
8
INV
Inversion Input. Drive INV high to internally swap RO logic level with respect to A
and B signals.
—
9
FAULT
—
—
EP
Ground
Inverting Driver Output
Fault Flag Output. FAULT asserts high in overcurrent conditions or if A/B are forced
below GND or above VCC when the driver is enabled. FAULT is referenced to VL.
Exposed Pad
Function Tables
Table 1. Termination Resistor Control
(MAX13450E/MAX13451E)
TERM
Low
DE
RE
X
TERMINATION RESISTOR
X
High
X
X
Not activated
Activated
RE
High
Low
TERM
High
STATE
Shutdown
Table 3. Function Table for Transmitter
(MAX13450E)
INPUT
Low
DI
Y
Z
Low
X
High-Z
High-Z
Low
Low
High
High
High
Low
OUTPUT
A-B
RO
X
High-Z
R -50mV or Open
High
P -200mV
Low
Table 5. INV Input Function Table for
Transmitter (MAX13451E)
INPUT
OUTPUT
DE
INV
DI
A
B
Low
X
X
High-Z
High-Z
Low
Low
High
High
High
Low
Low
High
Low
High
Low
High
OUTPUT
DE
High
INPUT
RE
High
Table 2. Shutdown Control (MAX13450E/
MAX13451E)
DE
Table 4. Function Table for Receiver
(MAX13450E)
Low
High
High
12 �������������������������������������������������������������������������������������
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
Table 6. INV Input Function Table for
Receiver (MAX13451E)
INPUT
RE
High
A-B
RO
X
X
High-Z
Low
R -50mV or
Short or Open
High
P -200mV
Low
R -50mV or
Open
Low
P -200mV
High
High
VL
VCC
SRL
OUTPUT
INV
Low
Functional Diagram (MAX13450E)
Detailed Description
The MAX13450E is a full-duplex, RS-485/RS-422compatible transceiver and the MAX13451E is a halfduplex, RS-485/RS-422-compatible transceiver. Both
devices have an internal 100I/120I termination resistor.
The MAX13450E/MAX13451E have a VL supply voltage
input to support down to a +1.8V voltage logic interface.
The MAX13450E/MAX13451E feature a 1/8-unit load
receiver input impedance, allowing up to 256 transceivers on the bus. All line interface pins are protected to
Q30kV ESD based on the HBM. These devices also
include fail-safe circuitry, guaranteeing a defined logiclevel receiver output when the receiver inputs are open
or shorted.
The MAX13450E/MAX13451E allow slew-rate-limited
driver outputs for lower data rates below 500kbps. The
SRL reduces the slew rate, which reduces EMI emissions
and reflections caused by improperly terminated cables.
The MAX13451E has a FAULT output that indicates a
fault condition on the driver. The MAX13451E also has an
INV input that inverts the phase of A and B pins.
Termination Resistor
The MAX13450E/MAX13451E feature a selectable internal termination resistor. Drive the TERM input low to
enable the internal termination resistor. Drive the TERM
input high to disable the internal termination resistor.
Z
DI
D
Y
DE
MAX13450E
TERM
LOGIC-LEVEL
TRANSLATION
RE
B
RO
A
TERM100
GND
Drive the TERM100 input high to select the 100I termination resistor. Drive TERM100 input low to select the
120I termination resistor.
INV Input (MAX13451E)
The INV input of the MAX13451E reverses the polarity
of the RO receiver output (see Table 5 and 6). If the INV
input is high then the RO output is low under fail-safe
receiver conditions. This is the opposite polarity of normal fail-safe operations.
Fault Condition (MAX13451E)
The MAX13451E also has a FAULT output to indicate a
fault condition. The FAULT output is active high when
there is a short circuit at the driver’s output, an over/
undervoltage at the driver’s outputs, or the device’s temperature is higher than +150NC.
______________________________________________________________________________________ 13
MAX13450E/MAX13451E
Function Tables
(continued)
MAX13450E/MAX13451E
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
Thermal Shutdown
When the devices’ temperature goes over +150NC, the
termination resistor turns off, and the transmitter shuts
down while the receiver stays active.
Fail Safe
The MAX13450E 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. This is done by setting the receiver
input threshold between -50mV and -200mV. If the differential receiver input voltage (A - B) is greater than
or equal to -50mV, RO is logic-high. If (A - B) is less
than or equal to -200mV, RO is logic-low. In the case
of a terminated bus with all transmitters disabled, the
receiver’s differential input voltage is pulled to 0V by the
termination resistor. With the receiver thresholds of the
MAX13450E, this results in RO being logic-high.
The MAX13451E has the same fail-safe receiver behavior
as the MAX13450E when the INV input is low. When the
INV input is high, RO is low under the fail-safe condition.
ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electrostatic discharges encountered during handling and
assembly. The driver outputs and receiver inputs of the
MAX13450E/MAX13451E have extra protection against
static electricity. The ESD structures withstand high ESD
in all states: normal operation, shutdown, and powered
down. After an ESD event, the MAX13450E/MAX13451E
keep working without latchup or damage.
ESD protection can be tested in various ways. The transmitter outputs and receiver inputs of the MAX13450E/
MAX13451E are characterized for protection to the following limits:
• Q30kV using the Human Body Model
• Q
15kV using the Air Gap Discharge Method specified
in IEC 61000-4-2
• Q
7kV using the Contact Discharge Method specified
in IEC 61000-4-2
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents test
setup, test methodology, and test results.
Human Body Model
Figure 11a shows the Human Body Model, and Figure
11b shows the current waveform it generates when discharged into a low impedance. This model consists of a
100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the test device through a
1.5kI resistor.
IEC 61000-4-2
The IEC 61000-4-2 standard covers ESD testing and
performance of finished equipment. However, it does not
specifically refer to integrated circuits. The MAX13450E/
MAX13451E help equipment designs to meet IEC 610004-2, without the need for additional ESD-protection
components. The major difference between tests done
using the Human Body Model and IEC 61000-4-2 is
higher peak current in IEC 61000-4-2 because series
resistance is lower in the IEC 61000-4-2 model. Hence,
the ESD withstand voltage measured to IEC 61000-4-2
is generally lower than that measured using the Human
Body Model. Figure 11c shows the IEC 61000-4-2 model,
and Figure 11d shows the current waveform for the IEC
61000-4-2 ESD Contact Discharge test.
Applications Information
Typical Applications
The MAX13450E transceiver is designed for full-duplex,
bidirectional data communications on point-to-point
or multipoint bus transmission lines (Figure 12). The
MAX13451E transceiver is designed for half-duplex,
bidirectional data communications on point-to-point or
multipoint bus transmission lines (Figure 13).
256 Transceivers on the Bus
The standard RS-485 receiver input impedance is oneunit load, and the standard driver can drive up to 32-unit
loads. The MAX13450E/MAX13451E have a 1/8-unit load
receiver input impedance, allowing up to 256 transceivers to be connected in parallel on one communication
line. Any combination of these devices, as well as other
RS-485 transceivers with a total of 32-unit loads or fewer,
can be connected to the line.
Reduced EMI and Reflections
The MAX13450E/MAX13451E feature reduced slew-rate
drivers that minimize EMI and reduce reflections caused
by improperly terminated cables, allowing error-free data
transmission up to 500kbps.
14 �������������������������������������������������������������������������������������
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
RD
1500Ω
CHARGE-CURRENT
LIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
CS
100pF
RC
50MΩ TO 100MΩ
DISCHARGE
RESISTANCE
CHARGE-CURRENT
LIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
STORAGE
CAPACITOR
Figure 11a. Human Body ESD Test Model
IP 100%
90%
DISCHARGE
RESISTANCE
DEVICE
UNDER
TEST
STORAGE
CAPACITOR
Figure 11c. IEC 61000-4-2 ESD Test Model
I
100%
90%
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
IPEAK
Ir
CS
150pF
RD
330Ω
AMPS
36.8%
10%
0
10%
0
TIME
tRL
tr = 0.7ns TO 1ns
tDL
CURRENT WAVEFORM
t
30ns
60ns
Figure 11b. Human Body Current Waveform
Figure 11d. IEC 61000-4-2 ESD Generator Current Waveform
Typical Application Circuits
Z
B
Y
A
B
Z
A
Y
D
R
R
D
MAX13450E
MAX13450E
MASTER
END SLAVE
R
D
R
D
SLAVE 1
R
D
SLAVE 2
SLAVE N
Figure 12. Full-Duplex, Multidrop (MAX13450E)
______________________________________________________________________________________ 15
MAX13450E/MAX13451E
RC
1MΩ
MAX13450E/MAX13451E
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
Typical Application Circuits (continued)
MAX13451E
MAX13451E
D
D
B
B
A
A
R
R
R
D
R
R
D
SLAVE 1
D
SLAVE 2
SLAVE N
Figure 13. Half-Duplex, Multidrop, and Point-to-Point Systems (MAX13451E)
Package Information
Low-Power Shutdown Mode
Drive RE high, DE low, and TERM high to enter lowpower shutdown mode (see Table 2).
Chip Information
PROCESS: BiCMOS
For the latest package outline information and land patterns,
go to www.maxim-ic.com/packages. Note that a “+”, “#”, or
“-” in the package code indicates RoHS status only. Package
drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
14 TSSOP-EP
U14E+3
21-0108
16 �������������������������������������������������������������������������������������
RS-485 Transceivers with Integrated
100Ω/120Ω Termination Resistors
REVISION
NUMBER
REVISION
DATE
0
4/10
DESCRIPTION
Initial release
PAGES
CHANGED
—
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
© 2010
Maxim Integrated Products 17
Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX13450E/MAX13451E
Revision History