19-1058; Rev 1; 8/09
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
Features
♦ Wide +6V to +28V Input Supply Range
♦ +5V Output Supplies Up to 20mA to External
Circuitry
♦ Internal LDO
♦ Low 65µA (typ) Shutdown Supply Current
♦ Extended ESD Protection
±15kV Human Body Model (MAX13412E/
MAX13413E)
±14kV Human Body Model (MAX13410E/
MAX13411E)
♦ 1/8-Unit Load, Allowing Up to 256 Transceivers on
the Bus
♦ -40°C to +85°C Operating Temperature Range
♦ Fail-Safe
♦ Slew-Rate Limited and Full-Speed Versions
♦ Up to 16Mbps Data Rate on Full-Speed Versions
Applications
Isolated
- RS-485 Interfaces
Industrial Equipment
Utility Meters
Telecomm Equipment
Pin Configurations
TOP VIEW
RO
1
RE
2
DE
+
3
MAX13410E
MAX13411E
DI 4
*EP
8
VCC
7
B
6
A
5
GND
SO
*EXPOSED PAD CONNECTED TO GROUND
Pin Configurations continued at end of data sheet.
Ordering Information/Selector Guide
PART
PIN-PACKAGE
AutoDirection
DATA RATE (max)
5V LDO OUTPUT
MAX13410EESA+
8 SO-EP*
No
500kbps
No
MAX13411EESA+
8 SO-EP*
No
16Mbps
No
Note: All devices operate over the -40°C to +85°C operating
temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Ordering Information/Selector Guide continued at end of data
sheet.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX13410E–MAX13415E
General Description
The MAX13410E–MAX13415E are half-duplex RS-485-/RS422-compatible transceivers optimized for isolated applications. These devices feature an internal low-dropout
regulator (LDO), one driver, and one receiver. The internal LDO allows the part to operate from an unregulated
power supply of up to 28V. The AutoDirection feature
reduces the number of optical isolators needed in isolated applications. Other features include enhanced ESD
protection, fail-safe circuitry, slew-rate limiting, and fullspeed operation.
The MAX13410E–MAX13415E internal LDO generates a
5V ±10% power supply that is used to power its internal
circuitry. The MAX13412E–MAX13415E bring the 5V to an
output VREG that allows the user to power additional
external circuitry with up to 20mA to further reduce external components. The MAX13410E/MAX13411E do not
have a 5V output and come in industry-compatible
pinouts. This allows easy replacement in existing designs.
The MAX13410E–MAX13415E feature a 1/8-unit load
receiver input impedance, allowing up to 256 transceivers on the bus. All driver outputs are ESD protected
using the Human Body Model. These devices also
include fail-safe circuitry (MAX13410E/MAX13411E/
MAX13414E/MAX13415E only), guaranteeing a logichigh receiver output when the receiver inputs are open
or shorted. The receiver outputs a logic-high when the
transmitter on the terminated bus is disabled (high
impedance).
The MAX13412E/MAX13413E feature Maxim’s proprietary AutoDirection control. This architecture eliminates
the need for the DE and RE control signals. In isolated
applications, this reduces the cost and size of the system by reducing the number of optical isolators required.
The MAX13410E/MAX13412E/MAX13414E feature
reduced slew-rate drivers that minimize EMI and reduce
reflections caused by improperly terminated cables,
allowing error-free transmission up to 500kbps. The
MAX13411E/MAX13413E/MAX13415E are not slew-rate
limited, allowing transmit speeds up to 16Mbps.
The MAX13410E–MAX13415E are available in an 8-pin
SO package with an exposed paddle to improve power
dissipation, and operate over the extended -40°C to
+85°C temperature range.
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND.)
VCC .........................................................................-0.3V to +30V
RE, DE/RE, DE, DI, RO, VREG ..................................-0.3V to +6V
A, B............................................................................-8V to +13V
Short-Circuit Duration (RO, A, B) to GND ................. Continuous
Continuous Power Dissipation (TA = +70°C)
8-Pin SO-EP (derate 19.2mW/°C above +70°C) ........1539mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range ............................-65°C to +150°C
Junction Temperature ......................................................+150°C
θJA (Note 1)...................................................................52.0°C/W
θJC (Note 1).....................................................................6.0°C/W
Lead Temperature (soldering, 10s) ................................+300°C
Note 1: Package thermal resistances were obtained using the method described in JEDEC specificactions JESD51-7 using a four layer board.
For detailed information on package consitencies refer to www.maxim-ic/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 = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
Supply Voltage
SYMBOL
VCC
CONDITIONS
5.5
VCC = +28V, ILOAD = 0mA
4.5
5
5.5
IREG
VCC > +7.5V
VDO
VCC = +5V, IOUT = 20mA
CS
Guaranteed by design,
MAX13412E–MAX13415E
ISHDN
V
5
LDO Dropout Voltage
Shutdown Current
UNITS
28.0
4.5
LDO Output Current
ICC
MAX
VCC = +7.5V, ILOAD = 20mA
VREG
Supply Current
TYP
6.0
LDO Output Voltage
Minimum Bypass Capacitor on VREG
MIN
(Note 3)
20
0.5
V
mA
V
1
µF
RE, DE = high/no load
(MAX13410E/MAX13411E)
10
RE, DE/RE = high, DI = low/no load
(MAX13412E–MAX13415E)
10
mA
DE = low, RE = high
(MAX13410E/MAX13411E)
45
µA
Thermal-Shutdown Threshold
TTS
+150
°C
Thermal-Shutdown Threshold
Hysteresis
TTSH
15
°C
DRIVER
Differential Driver Output
Change in Magnitude of Differential
Output Voltage
Driver Common-Mode Output Voltage
Change In Magnitude of CommonMode Voltage
VOD
RDIFF = 100Ω, Figure 1
2.0
5.5
RDIFF = 54Ω, Figure 1
1.5
5.5
5.5
ΔVOD
RDIFF = 100Ω or 54Ω, Figure 1
0.2
V
VOC
RDIFF = 100Ω or 54Ω, Figure 1
3
V
ΔVOC
RDIFF = 100Ω or 54Ω, Figure 1
0.2
V
0.8
V
±1
µA
1.0
V
Input High Voltage
VIH
DI, DE, RE, DE/RE
Input Low Voltage
VIL
DI, DE, RE, DE/RE
Input Current
IIN
DI, DE, RE, DE/RE
Driver-Disable Threshold
VDT
TA = +25°C (MAX13412E/MAX13413E)
2
V
No load
1
2.0
0.6
_______________________________________________________________________________________
V
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
Driver Short-Circuit Output Current
IOSD
Driver Short-Circuit-Foldback Output
Current
IOSDF
CONDITIONS
MIN
TYP
0V < VOUT < +12V
MAX
+250
-7V < VOUT < 0V
-250
(VCC - 1V) < VOUT < +12V
20
-7V < VOUT < 0V
-20
UNITS
mA
mA
RECEIVER
Input Current (A and B)
Receiver Differential Threshold
Voltage
IA, B
VTH
RE, DE, DE/RE =
GND, VCC = GND
VIN = +12V
VIN = -7V
125
-100
-7V < VCM < +12V
(MAX13410E/MAX13411E)
-200
-50
-7V < VLM < +12V
(MAX13412E/MAX13413E)
-100
100
µA
mV
Receiver Input Hysteresis
ΔVTH
VA + VB = 0V
Output High Voltage
VOH
IO = -1mA, VA - VB > VTH
Output Low Voltage
VOL
IO = +1mA, VA - VB < -VTH
Three-State Output Current at Receiver
IOZR
0 < VO < VREG
Receiver-Input Resistance
RIN
-7V < VCM < +12V
96
Receiver-Output Short-Circuit Current
IOSR
0V < VRO < VREG
±8
15
mV
VREG - 0.6
V
0.01
0.4
V
±1
µA
±95
kΩ
mA
ESD PROTECTION
ESD Protection (A, B)
Human Body Model
(MAX13412E/MAX13413E)
±15
kV
ESD Protection (A, B)
Human Body Model
(MAX13410E/MAX13411E)
±14
kV
ESD Protection (All Other Pins)
Human Body Model
±2
kV
SWITCHING CHARACTERISTICS–MAX13410E
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Driver Propagation Delay
Driver Differential Output
Rise or Fall Time
Driver Differential Output Skew
|tDPLH - tDPHL|
Maximum Data Rate
tDPLH
tDPHL
tHL
tLH
tDSKEW
RDIFF = 54Ω, CL = 50pF,
Figures 2a and 3a
RDIFF = 54Ω, CL = 50pF,
Figures 2a and 3a
150
1000
150
1000
250
900
250
900
RDIFF = 54Ω, CL = 50pF,
Figures 2a and 3a
fMAX
140
500
ns
ns
ns
kbps
Driver Enable from Shutdown to
Output High
S2 closed, Figure 4,
tDZH(SHDN)
RL = 500Ω, CL = 100pF
11
µs
Driver Enable from Shutdown to
Output Low
tDZL(SHDN)
S2 closed, Figure 4,
RL = 500Ω, CL = 100pF
6
µs
_______________________________________________________________________________________
3
MAX13410E–MAX13415E
ELECTRICAL CHARACTERISTICS (continued)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
SWITCHING CHARACTERISTICS–MAX13410E (continued)
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Driver Enable to Output High
tDZH
S2 closed, Figure 4,
RL = 500Ω, CL = 100pF
2500
ns
Driver Enable to Output Low
tDZL
S1 closed, Figure 4,
RL = 500Ω, CL = 100pF
2500
ns
Driver Disable from Output High
tDHZ
S2 closed, Figure 4,
RL = 500Ω, CL = 100pF
100
ns
Driver Disable from Output Low
tDLZ
S1 closed, Figure 4,
RL = 500Ω, CL = 100pF
100
ns
700
ns
Time to Shutdown
tSHDN
50
340
RECEIVER
Receiver Propagation Delay
Receiver Output Skew
tRPLH
tRPHL
tRSKEW
200
CL = 15pF (at RO), Figures 5 and 6
200
CL = 15pF (at RO), Figures 5 and 6
30
500
ns
ns
Maximum Data Rate
fMAX
Receiver Enable to Output High
tRZH
S2 closed, Figure 7, CL = 15pF
50
kbps
ns
Receiver Enable to Output Low
tRZL
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Disable Time from High
tRZH
S2 closed, Figure 7, CL = 15pF
50
ns
Receiver Disable Time from Low
tRLZ
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Enable from Shutdown to
Output High
tRZH(SHDN) S2 closed, Figure 7, CL = 15pF
14
µs
Receiver Enable from Shutdown to
Output Low
tRZL(SHDN) S1 closed, Figure 7, CL = 15pF
3.5
µs
SWITCHING CHARACTERISTICS–MAX13411E
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Driver Propagation Delay
Driver Differential Output
Rise or Fall Time
Driver Differential Output Skew
|tDPLH - tDPHL|
Maximum Data Rate
tDPLH
tDPHL
tHL
tLH
tDSKEW
RDIFF = 54Ω, CL = 50pF, Figures 2a
and 3a
50
RDIFF = 54Ω, CL = 50pF, Figures 2a
and 3a
15
50
15
RDIFF = 54Ω, CL = 50pF, Figures 2a
and 3a
fMAX
8
16
ns
ns
ns
Mbps
Driver Enable from Shutdown to
Output High
S2 closed, Figure 4,
tDZH(SHDN)
RL = 500Ω, CL = 100pF
11
µs
Driver Enable from Shutdown to
Output Low
tDZL(SHDN)
S2 closed, Figure 4,
RL = 500Ω, CL = 100pF
6
µs
tDZH
S2 closed, Figure 4,
RL = 500Ω, CL = 100pF
70
ns
Driver Enable to Output High
4
_______________________________________________________________________________________
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
70
ns
Driver Enable to Output Low
tDZL
S1 closed, Figure 4,
RL = 500Ω, CL = 100pF
Driver Disable from Output High
tDHZ
S2 closed, Figure 4,
RL = 500Ω, CL = 100pF
50
ns
Driver Disable from Output Low
tDLZ
S1 closed, Figure 4,
RL = 500Ω, CL = 100pF
50
ns
RECEIVER
Receiver Propagation Delay
Receiver Output Skew
tRPLH
tRPHL
tRSKEW
75
CL = 15pF (at RO), Figures 5 and 6
75
CL = 15pF (at RO), Figures 5 and 6
8
16
ns
ns
Maximum Data Rate
fMAX
Receiver Enable to Output High
tRZH
S2 closed, Figure 7, CL = 15pF
50
Mbps
ns
Receiver Enable to Output Low
tRZL
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Disable Time from High
tRZH
S2 closed, Figure 7 , CL = 15pF
50
ns
Receiver Disable Time from Low
tRLZ
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Enable from Shutdown to
Output High
tRZH(SHDN) S2 closed, Figure 7, CL = 15pF
14
µs
Receiver Enable from Shutdown to
Output Low
tRZL(SHDN) S1 closed, Figure 7, CL = 15pF
3.5
µs
SWITCHING CHARACTERISTICS–MAX13412E
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Driver Propagation Delay
Driver Differential Output
Rise or Fall Time
tDPLH
tDPHL
tHL
tLH
Maximum Data Rate
fMAX
Driver Disable Delay
tDDD
RL = 110Ω, CL = 50pF, Figures 2b
and 3b
200
1000
200
1000
RL = 110Ω, CL = 50pF, Figures 2b
and 3b
250
900
250
900
500
RL = 110Ω, CL = 50pF, Figure 3b
ns
ns
kbps
2500
ns
RECEIVER
Receiver Propagation Delay
Receiver Output Skew
tRPLH
tRPHL
tRSKEW
200
CL = 15pF, Figures 5 and 6
200
CL = 15pF, Figures 5 and 6
30
500
ns
ns
Maximum Data Rate
fMAX
Receiver Enable to Output High
tRZH
S2 closed, Figure 7, CL = 15pF
50
kbps
ns
Receiver Enable to Output Low
tRZL
S1 closed, Figure 7, CL = 15pF
50
ns
_______________________________________________________________________________________
5
MAX13410E–MAX13415E
SWITCHING CHARACTERISTICS–MAX13411E (continued)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
SWITCHING CHARACTERISTICS–MAX13412E (continued)
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
MAX
UNITS
Receiver Disable Time from Low
PARAMETER
SYMBOL
tRLZ
S1 closed, Figure 7, CL = 15pF
CONDITIONS
MIN
TYP
50
ns
Receiver Disable Time from High
tRZH
S2 closed, Figure 7, CL = 15pF
50
ns
Receiver Enable Delay
tRED
RL = 110Ω, CL = 50pF, Figure 3
2500
ns
SWITCHING CHARACTERISTICS–MAX13413E
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Driver Propagation Delay
Driver Differential Output
Rise or Fall Time
tDPLH
tDPHL
tHL
tLH
Maximum Data Rate
fMAX
Driver Disable Delay
tDDD
RL = 110Ω, CL = 50pF, Figures 2b
and 3b
50
RL = 110Ω, CL = 50pF, Figures 2b
and 3b
15
50
15
16
ns
ns
Mbps
RL = 110Ω, CL = 50pF, Figure 3b
70
ns
RECEIVER
Receiver Propagation Delay
Receiver Output Skew
tRPLH
tRPHL
tRSKEW
80
CL = 15pF, Figures 5 and 6
80
CL = 15pF, Figures 5 and 6
13
16
ns
ns
Maximum Data Rate
fMAX
Receiver Enable to Output High
tRZH
S2 closed, Figure 7, CL = 15pF
50
Mbps
ns
Receiver Enable to Output Low
tRZL
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Disable Time from Low
tRLZ
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Disable Time from High
tRZH
S2 closed, Figure 7, CL = 15pF
50
ns
Receiver Enable Delay
tRED
RL = 110Ω, Figure 3, CL = 50pF
70
ns
SWITCHING CHARACTERISTICS–MAX13414E
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Driver Propagation Delay
Driver Differential Output
Rise or Fall Time
Driver Differential Output Skew
|tDPLH - tDPHL|
6
tDPLH
tDPHL
tHL
tLH
tDSKEW
RDIFF = 54Ω, CL = 50pF, Figures 2a
and 3a
RDIFF = 54Ω, CL = 50pF, Figures 2a
and 3a
200
1000
200
1000
250
900
250
900
RDIFF = 54Ω, CL = 50pF, Figures 2a
and 3a
_______________________________________________________________________________________
140
ns
ns
ns
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
500
UNITS
Maximum Data Rate
fMAX
kbps
Driver Enable to Output High
tDZH
S2 closed, Figure 4,
RL = 500Ω CL = 100pF
2500
ns
Driver Enable to Output Low
tDZL
S1 closed, Figure 4,
RL = 500Ω CL = 100pF
2500
ns
Driver Disable from Output High
tDHZ
S2 closed, Figure 4,
RL = 500Ω, CL = 100pF
100
ns
Driver Disable from Output Low
tDLZ
S1 closed, Figure 4,
RL = 500Ω, CL = 100pF
100
ns
RECEIVER
Receiver Propagation Delay
Receiver Output Skew
tRPLH
tRPHL
tRSKEW
200
CL = 15pF (at RO), Figures 5 and 6
200
CL = 15pF (at RO), Figures 5 and 6
30
500
ns
ns
Maximum Data Rate
fMAX
Receiver Enable to Output High
tRZH
S2 closed, Figure 7, CL = 15pF
50
kbps
ns
Receiver Enable to Output Low
tRZL
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Disable Time from Low
tRLZ
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Disable Time from High
tRZH
S2 closed, Figure 7, CL = 15pF
50
ns
SWITCHING CHARACTERISTICS–MAX13415E
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Driver Propagation Delay
Driver Differential Output
Rise or Fall Time
Driver Differential Output Skew
|tDPLH - tDPHL|
tDPLH
tDPHL
tHL
tLH
tDSKEW
RDIFF = 54Ω, CL = 50pF, Figures 2a
and 3a
50
RDIFF = 54Ω, CL = 50pF, Figures 2a
and 3a
15
50
15
RDIFF = 54Ω, CL = 50pF, Figures 2a
and 3a
8
16
ns
ns
ns
Maximum Data Rate
fMAX
Mbps
Driver Enable to Output High
tDZH
S2 closed, Figure 4,
RL = 500Ω, CL = 15pF
70
ns
Driver Enable to Output Low
tDZL
S1 closed, Figure 4,
RL = 500Ω, CL = 15pF
70
ns
Driver Disable from Output High
tDHZ
S2 closed, Figure 4,
RL = 500Ω, CL = 15pF
50
ns
_______________________________________________________________________________________
7
MAX13410E–MAX13415E
SWITCHING CHARACTERISTICS–MAX13414E (continued)
SWITCHING CHARACTERISTICS–MAX13415E (continued)
(VCC = +6.0V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +7.5V, CS = 1µF, and TA = +25°C.) (Note 2)
PARAMETER
SYMBOL
Driver Disable from Output Low
CONDITIONS
MIN
TYP
S1 closed, Figure 4,
RL = 500Ω, CL = 15pF
tDLZ
MAX
UNITS
50
ns
RECEIVER
tRPLH
Receiver Propagation Delay
75
CL = 15pF (at RO), Figures 5 and 6
tRPHL
Receiver Output Skew
tRSKEW
ns
75
CL = 15pF (at RO), Figures 5 and 6
8
ns
Maximum Data Rate
fMAX
Receiver Enable to Output High
tRZH
S2 closed, Figure 7, CL = 15pF
50
ns
Receiver Enable to Output Low
tRZL
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Disable Time from Low
tRLZ
S1 closed, Figure 7, CL = 15pF
50
ns
Receiver Disable Time from High
tRZH
S2 closed, Figure 7, CL = 15pF
50
ns
16
Mbps
Note 2: CS is the compensation capacitor on VREG for the MAX13412E–MAX13415E versions. CS must have an ESR value of 20mΩ or less.
Note 3: Parameters are guaranteed for +6.0V ≤ VCC ≤ +28V.
Typical Operating Characteristics
(VCC = +7.5V, TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. TEMPERATURE
2.0
DE = LOW
20
15
10
-15
10
35
TEMPERATURE (°C)
60
85
50
40
30
20
10
0
-40
MAX13410E-15E toc03
25
5
0
8
30
60
OUTPUT CURRENT (mA)
DE = HIGH
MAX13410E-15E toc02
6.0
35
OUTPUT CURRENT (mA)
NO LOAD
4.0
OUTPUT CURRENT
vs. RECEIVER OUTPUT LOW VOLTAGE
OUTPUT CURRENT
vs. RECEIVER OUTPUT HIGH VOLTAGE
MAX13410E-15E toc01
8.0
SUPPLY CURRENT (mA)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
0
0
1
2
3
OUTPUT HIGH VOLTAGE (V)
4
5
0
1
2
3
OUTPUT LOW VOLTAGE (V)
_______________________________________________________________________________________
4
5
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
5.0
4.8
4.6
4.4
IO = -1mA
0.4
0.3
0.2
80
0.1
MAX13410E-15E toc06
OUTPUT HIGH VOLTAGE (V)
5.2
0.5
OUTPUT CURRENT (mA)
IO = +1mA
OUTPUT LOW VOLTAGE (V)
MAX13410E-15E toc04
5.4
DIFFERENTIAL OUTPUT CURRENT
vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX13410E-15E toc05
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
60
40
20
4.2
4.0
-40
10
35
60
-15
10
35
60
85
0
1
2
3
4
5
TEMPERATURE (°C)
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
OUTPUT CURRENT
vs. TRANSMITTER OUTPUT HIGH VOLTAGE
OUTPUT CURRENT
vs. TRANSMITTER OUTPUT LOW VOLTAGE
2.5
2.0
1.5
1.0
80
60
40
100
-15
10
35
60
85
40
-7 -6 -5 -4 -3 -2 -1
0 1
2
3
4
0
5
2
4
6
8
10
12
OUTPUT LOW VOLTAGE (V)
SHUTDOWN CURRENT
vs. TEMPERATURE
DRIVER PROPAGATION vs. TEMPERATURE
(MAX13412E)
DRIVER PROPAGATION vs. TEMPERATURE
(MAX13413E)
70
60
50
40
30
20
10
0
-15
10
35
TEMPERATURE (°C)
60
85
RL = 110Ω
600
500
tRPLH
400
300
tRPHL
200
100
0
-40
40
DRIVER PROPAGATION DELAY (ns)
80
700
DRIVER PROPAGATION DELAY (ns)
MAX13410E-15E toc10
90
MAX13410E-15E toc12
OUTPUT HIGH VOLTAGE (V)
MAX13410E-15E toc11
TEMPERATURE (°C)
100
-40
60
0
0
-40
80
20
20
0.5
MAX13410E-15E toc09
100
120
OUTPUT CURRENT (mA)
3.0
MAX13410E-15E toc08
3.5
120
OUTPUT CURRENT (mA)
RDIFF = 54Ω
0
SHUTDOWN CURRENT (μA)
0
-40
85
MAX13410E-15E toc07
DIFFERENTIAL OUTPUT VOLTAGE (V)
4.0
0
-15
RL = 110Ω
35
30
tRPHL
25
20
15
10
tRPLH
5
0
-15
10
35
TEMPERATURE (°C)
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
9
MAX13410E–MAX13415E
Typical Operating Characteristics (continued)
(VCC = +7.5V, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = +7.5V, TA = +25°C, unless otherwise noted.)
RECEIVER PROPAGATION vs.TEMPERATURE
(MAX13410E/MAX13412E)
RECEIVER PROPAGATION vs.TEMPERATURE
(MAX13411E/MAX13413E)
30
tRPLH
15
0
MAX13410E-15E toc14
RECEIVER PROPAGATION DELAY (ns)
tRPHL
45
DRIVER PROPAGATION (250kbps)
(MAX13412E)
MAX13410E-15E toc15
60
MAX13410E-15E toc13
60
RECEIVER PROPAGATION DELAY (ns)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
45
DI
2V/div
tRPHL
30
A-B
5V/div
15
tRPLH
0
-40
-15
10
35
60
85
-40
-15
10
35
60
TEMPERATURE (°C)
TEMPERATURE (°C)
DRIVER PROPAGATION (16kbps)
(MAX13413E)
RECEIVER PROPAGATION (16kbps)
(MAX13413E)
MAX13410E-15E toc16
85
1μs/div
DRIVING A LARGE CAPACITIVE LOAD 16nF
(19.2kbps) (MAX13412E)
MAX13410E-15E toc18
MAX13410E-15E toc17
A
2V/div
DI
2V/div
DI
2V/div
B
2V/div
A-B
2V/div
RO
2V/div
A-B
5V/div
20ns/div
10μs/div
20ns/div
DRIVING A LARGE CAPACITIVE LOAD 16nF
(50kbps) (MAX13413E)
DRIVING A LARGE CAPACITIVE LOAD 16nF
(1Mbps) (MAX13413E)
MAX13410E-15E toc20
MAX13410E-15E toc19
DI
2V/div
DI
2V/div
A-B
5V/div
400ns/div
10
A-B
2V/div
1μs/div
______________________________________________________________________________________
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
A
RDIFF / 2
VOD
CL
RDIFF / 2 VOC
B
Figure 1. Driver DC Test Load
5V
DE
RL
A
DI
VID
RDIFF
DI
CL
B
A
VREG
GND
VID
B
CL
RL
Figure 2a. Driver-Timing Test Circuit
Figure 2b. Driver-Timing Test Circuit
f = 1MHz, tLH ≤ 3ns, tHL ≤ 3ns
5V
DI
1.5V
1.5V
0
1/2 VO
tDPHL
tDPLH
B
A
1/2 VO
VO
VDIFF = VA - VB
VO
VDIFF
90%
90%
0
-VO
10%
10%
tHL
tLH
tDSKEW = |tDPLH - tDPHL|
Figure 3a. Driver Propagation Delays
______________________________________________________________________________________
11
MAX13410E–MAX13415E
Test Circuits and Waveforms
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
MAX13410E–MAX13415E
Test Circuits and Waveforms (continued)
RE = VCC
5V
f = 1MHz, tLH ≤ 3ns, tHL ≤ 3ns
1.5V
DI
1.5V
0
1/2 VO
tDPHL
tDPLH
B
VO
A
1/2 VO
RO
tDDD, tRED
(RO PULLED LOW)
O
VDIFF = VA - VB
VO
VDIFF
90%
90%
0
10%
10%
-VO
tHL
tLH
Figure 3b. Driver Propagation Delays
VCC
1.5V
DE
1.5V
0
tDLZ
tDZL(SHDN)
A, B
500Ω
OUTPUT
UNDER TEST
S1
2.3V
5V
OUTPUT NORMALLY LOW
VOL
S2
CL
VOL + 0.5V
OUTPUT NORMALLY HIGH
A, B
2.3V
VOH
VOH + 0.5V
0
tDZH(SHDN)
Figure 4. Driver Enable and Disable Times
B
ATE
R
VID
RECEIVER
OUTPUT
A
Figure 5. Receiver-Propagation-Delay Test Circuit
12
______________________________________________________________________________________
tDHZ
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
f = 1MHz, tLH ≤ 3ns, tHL ≤ 3ns
A
1V
-1V
B
tRPLH
tRPHL
VOH
RO
1.5V
VOL
1.5V
tRSKEW = | tRPHL - tRPLH |
Figure 6. Receiver Propagation Delays
VREG
RE
1.5V
1.5V
0
tRZL(SHDN), tRZL
tRHZ
2.3V
VOH + 0.5V
VREG
1kΩ
RO
CL
15pF
S1
5V
RO
0
S2
OUTPUT NORMALLY HIGH
VREG
RO
OUTPUT NORMALLY LOW
2.3V
VOH + 0.5V
tRZH(SHDN), tRZH
tRHZ
0
DI = 0V
Figure 7. Receiver Enable and Disable Times
______________________________________________________________________________________
13
MAX13410E–MAX13415E
Test Circuits and Waveforms (continued)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
Pin Description
PIN
MAX13410E/
MAX13411E
MAX13412E/
MAX13413E
MAX13414E/
MAX13415E
NAME
FUNCTION
1
—
1
RO
Receiver Output. When receiver is enabled and VA - VB ≥ -50mV,
RO is high. If VA - VB ≤ -200mV, RO is low. Note: RO is referenced to
the LDO output (VREG).
2
—
—
RE
Receiver Output Enable. Drive RE low to enable RO. Drive RE high to
disable the RO output and put the RO output in a high-impedance
state.
3
—
—
DE
Driver Output Enable. Drive DE low to put the driver output in three-state.
Drive DE high to enable the driver.
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 an input to the internal state
machine that automatically enables and disables the driver (for the
MAX13412E/MAX13413E). See the function tables and General
Description for more information.
14
4
4
4
DI
5
5
5
GND
6
6
6
A
Noninverting Receiver Input and Noninverting Driver Output
7
7
7
B
Inverting Receiver Input and Inverting Driver Output
8
8
8
VCC
Positive Supply. Bypass VCC with a 0.1µF ceramic capacitor to GND.
—
1
—
RO
Receiver Output. When receiver is enabled and VA - VB ≥ -100mV,
RO is high. If VA - VB ≤ -100mV, RO is low. Note: RO is referenced to
the LDO output (VREG).
—
2
—
RE
Receiver Output Enable. Drive RE low to force the RO output to be
enabled. Drive RE high to let the AutoDirection circuit control RO.
—
3
3
VREG
LDO Output. VREG is fixed at +5V. Bypass VREG with a low ESR
(20mΩ or less) and a 1µF (min) ceramic capacitor.
—
—
2
DE/RE
Receiver and Driver Output Enable. Drive DE/RE low to enable RO
and disable the driver. Drive DE/RE high to disable RO and enable
the driver.
EP
EP
EP
EP
Ground
Exposed Pad. EP is internally connected to GND. For enhanced
thermal dissipation, connect EP to a copper area as large as
possible. Do not use EP as a sole ground connection.
______________________________________________________________________________________
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
RECEIVING
TRANSMITTING
INPUT
MAX13410E–MAX13415E
Function Tables for the MAX13410E/MAX13411E
INPUT
OUTPUT
OUTPUT
RE
DE
DI
B
A
RE
DE
A-B
RO
X
1
1
0
1
0
X
> -50mV
1
X
< -200mV
0
X
1
0
1
0
0
0
0
X
High impedance
High impedance
0
X
Open/Short
1
1
0
X
1
1
X
High impedance
1
0
X
High impedance
(shutdown)
High impedance (shutdown)
X = Don’t care, shutdown mode, driver, and receiver outputs are in high impedance.
Function Tables for the MAX13412E/MAX13413E
TRANSMITTING
INPUTS
OUTPUTS
DI
A - B > VDT
ACTION
A
0
X
Turn driver ON
0
B
1
1
False
If driver was OFF, keep it OFF
High impedance
High impedance
1
False
If driver was ON, keep it ON
1
0
1
True
Turn driver OFF
High impedance
High impedance
RECEIVING
INPUTS
OUTPUT
RE
A-B
DRIVER STATE
RECEIVER STATE
RO
0
> -100mV
X
ON
1
0
< -100mV
X
ON
0
1
X
ON
OFF
High impedance
1
> -100mV
OFF
ON
1
1
< -100mV
OFF
ON
0
X = Don’t care, shutdown mode, driver, and receiver outputs are in high impedance.
Function Tables for the MAX13414E/MAX13415E
RECEIVING
TRANSMITTING
INPUT
INPUT
OUTPUT
OUTPUT
DE/RE
DI
B
A
DE/RE
A-B
RO
0
X
High impedance
High impedance
0
> -50mV
1
< -200mV
0
1
1
0
1
0
1
0
1
0
0
Open/Short
1
1
X
High impedance
X = Don’t care, shutdown mode, driver, and receiver outputs are in high impedance.
______________________________________________________________________________________
15
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
Detailed Description
The MAX13410E–MAX13415E are half-duplex RS-485/
RS-422-compatible transceivers optimized for isolated
applications. These devices feature an internal LDO regulator, one driver, and one receiver. The internal LDO
allows the part to operate from an unregulated +6V to
+28V power supply. The AutoDirection feature reduces
the number of optical isolators needed in isolated applications. Other features include ±15kV ESD protection
(MAX13412E/MAX13413E only), ±14kV (MAX13410E/
MAX13411E only) fail-safe circuitry, slew-rate limiting, and
full-speed operation.
The MAX13410E–MAX13415E internal LDO generates a
5V ±10% power supply that is used to power its internal
circuitry. The MAX13412E–MAX13415E bring the 5V to an
output VREG that allows the user to power additional external circuitry with up to 20mA to further reduce external
components. The MAX13410E/MAX13411E do not have a
5V output and come in industry-compatible pinouts. This
allows easy replacement in existing designs.
The MAX13412E/MAX13413E feature Maxim’s proprietary AutoDirection control. This architecture eliminates
the need for the DE and RE control signals. In isolated
applications, this reduces the cost and size of the system by reducing the number of optical isolators required.
The MAX13410E/MAX13412E/MAX13414E feature
reduced slew-rate drivers that minimize EMI and reduce
reflections caused by improperly terminated cables,
allowing error-free transmission up to 500kbps. The
MAX13411E/MAX13413E/MAX13415E are not slew-rate
limited, allowing transmit speeds up to 16Mbps.
The MAX13410E–MAX13415E feature a 1/8-unit load
receiver input impedance, allowing up to 256 transceivers on the bus. All driver outputs are protected to
±15kV ESD using the Human Body Model. These
devices also include fail-safe circuitry, MAX13410E/
MAX13411E/MAX13414E/MAX13415E, guaranteeing a
logic-high receiver output when the receiver inputs are
open or shorted. The receiver outputs a logic-high
when the transmitter on the terminated bus is disabled
(high impedance).
Internal Low-Dropout Regulator
The MAX13410E–MAX13415E include an internal lowdropout regulator that allows it to operate from input voltages of up to +28V. The internal LDO has a set output
voltage of 5V ±10% that is used to power the internal circuitry of the device. The MAX13412E–MAX13415E offer
the LDO output at the VREG output. This allows additional
external circuitry to be powered without the need for
additional external regulators. The VREG output can
source up to 20mA.
16
When using these devices with high input voltages and
heavily loaded networks, special care must be taken
that the power dissipation rating of the package and
the maximum die temperature of the device is not
exceeded. Die temperature of the part can be calculated using the equation:
TDIE = [(θJC + θCA) x PDISS] + TAMBIENT, where
TDIE = Temperature of the Die
θJC = 6.0°C/W = Junction-to-Case Thermal Resistance
θCA = Case-to-Ambient Thermal Resistance
θJA = θJC + θCA = 52.0°C/W = Junction-to-Ambient
Thermal Resistance
PDISS = (ICC - VCC) + [(VCC - VREG) x IREG)] + [(VCC VOD) x IDRIVER] = Power Dissipation of the Part
TAMBIENT = Ambient Temperature
VCC = Voltage on the VCC Input
ICC = Current in to VCC
VREG = Voltage on the VREG Output
IREG = Current Drawn from the VREG Output
VOD = Voltage at the Driver Output (|VA - VB|)
IDRIVER = Current Driven Out of the Driver. Typically,
this is the current through the termination resistor.
The absolute maximum rating of the die temperature of
the MAX13410E–MAX13415E is +150°C. To protect the
part from overheating, there is an internal thermal shutdown that shuts down the part when the die temperature reaches +150°C. To prevent damage to the part,
and to prevent the part from entering thermal shutdown,
keep the die temperature below +150°C, plus some
margin. The circuit designer can minimize the die temperature by controlling the following parameters:
• VCC
•
IREG
•
θCA
Measuring the VCC Current
Measured current at the VCC pin is a function of the
quiescent current of the part, the amount of current that
the drivers must supply to the load, and in the case of
the MAX13412E–MAX13415E, the load on the VREG
output. In most cases, the load that the drivers must
supply will be the termination resistor(s). Ideally, the termination resistance should match the characteristic
impedance of the cable and is usually not a parameter
the circuit designer can easily change. In some lowspeed, short-cable applications, proper termination
______________________________________________________________________________________
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
Functional Diagram for the MAX13410E/MAX13411E/MAX13414E/MAX13415E
MAX13410E
MAX13411E
MAX13414E
MAX13415E
+
+
RO 1
LDO
8
VCC
RE 2
7
B
DE
6
A
5
GND
R
3
D
DI 4
RO 1
LDO
8
VCC
DE/RE 2
7
B
3
6
A
5
GND
VREG
R
D
DI 4
Functional Diagram for the MAX13412E/MAX13413E
LDO
VREG
MAX13412E
MAX13413E
1
RO
2
RE
VCC
8
VREG
+
R
-
3
RE
VREG
-
VDT
B 7
COM
+
RI
DI
A 6
STATE
MACHINE
DE
VREG
4
D
DI
GND
may not be necessary. In these cases, the drive current
can be reduced to minimize the die temperature.
Minimizing the load on the V REG output lowers the
power dissipation of the part and ultimately reduces the
maximum die temperature.
θCA
θCA is the thermal resistance from case to ambient and
is independent of the MAX13410E–MAX13415E. θCA is
primarily a characteristic of the circuit-board design. The
5
largest contributing factor of θCA will be the size and
weight of the copper connected to the exposed paddle
of the MAX13410E–MAX13415E. Lower the thermal
resistance by using as large a pad as possible.
Additionally, vias can be used to connect the pad to
other ground planes in the circuit board.
Note that θJC is the thermal resistance of the part from
junction-to-case temperature and is fixed at 6.0°C/W. It is
solely based on the die and package characteristics of
______________________________________________________________________________________
17
MAX13410E–MAX13415E
Functional Diagrams
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
the MAX13410E–MAX13415E. The circuit-board designer
has no control over this parameter.
Fail Safe
The MAX13410E/MAX13411E/MAX13414E/MAX13415E
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 0 by the termination.
With the receiver thresholds of the MAX13410E/
MAX13411E/MAX13414E/MAX13415E, the result is a
logic-high with a 50mV minimum noise margin. Unlike
previous fail-safe devices, the -50mV to -200mV threshold complies with the ±200mV EIA/TIA-485 standard.
AutoDirection Circuitry
The AutoDirection circuitry in the MAX13412E/
MAX13413E is a technique to minimize the number of
signals needed to drive the part. This is especially useful
in very low cost, isolated systems. In a typical isolated
system, an optocoupler is used for each control signal to
cross the isolation barrier. These optocouplers add cost,
size and consume power. Without the AutoDirection circuitry, three to four optocouplers may be required for
each transceiver. With the AutoDirection circuitry, the
number of optocouplers can be reduced to two.
Typical RS-485 transceivers have four signals on the
control side of the part. These are RO (receiver output),
RE (receiver enable), DE (driver enable), and DI (driver
input). In some cases, DE and RE may be connected
together to reduce the number of control signals to
three. In half-duplex systems, the RE and DE signals
determine if the part is transmitting or receiving. When
the part is receiving, the transmitter is in a high-impedance state. In a fully compliant RS-485 system, all three
or four signals are required. However, with careful
design and Maxim’s AutoDirection feature, the number
of control signals can be reduced to just RO and DI in
an RS-485 compatible system. This feature assumes the
DI input idles in the high state while the receiver portion
of the MAX13412E/MAX13413E is active. It also requires
an external pullup resistor on A and pulldown resistor on
B (see the typical application circuit, Figure 10). The following is a description of how AutoDirection works.
When DI is low, the MAX13412E/MAX13413E always
drive the bus low. When DI transitions from a low to a
18
high, the drivers actively drive the output until (A - B) >
VDT. Once (A - B) is greater than VDT, the drivers are
disabled, letting the pullup/pulldown resistors hold the
A and B lines in the correct state. This allows other
transmitters on the bus to pull the bus low.
Pullup and Pulldown Resistors
The pullup and pulldown resistors on the A and B lines
are required for proper operation of the MAX13412E
and MAX13413E, although their exact value is not critical. They function to hold the bus in the high state (A - B
> 200mV) when all the transmitters are in a high-impedance state due to either a shutdown condition or
AutoDirection. Determining the best value to use for
these resistors depends on many factors, such as termination resistor values, noise, number of transceivers on
the bus, etc. Size these resistors so that, under all conditions, (A - B) > 200mV for ALL receivers on the bus.
Idle State
When not transmitting data, the MAX13412E/
MAX13413E require the DI input to be driven high to
remain in the idle state. A conventional RS-485 transceiver has DE and RE inputs that are used to enable
and disable the driver and receiver. However, the
MAX13412E/MAX13413E do not have a DE input, and
instead use an internal state machine to enable and
disable the drivers. DI must be driven high to go to the
idle state.
Enhanced 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 MAX13410E–
MAX13415E have extra protection against static electricity.
Maxim’s engineers have developed state-of-the-art structures to protect these pins against ESD of ±15kV
(MAX13412E/MAX13413E) and ±14kV (MAX13410E/
MAX13411E) without damage. The ESD structures withstand high ESD in all states: normal operation, shutdown,
and powered down. After an ESD event, the MAX13410E–
MAX13415E keep working without latchup or damage.
ESD protection can be tested in various ways. The transmitter outputs and receiver inputs of the MAX13410E–
MAX13415E are characterized for protection to the
following limits:
±15kV using the Human Body Model (MAX13412E/
MAX13413E)
±14kV using the Human Body Model (MAX13410E/
MAX13411E)
______________________________________________________________________________________
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
CHARGE-CURRENTLIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
100pF
RD
1500Ω
IP 100%
90%
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Ir
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
AMPS
DEVICE
UNDER
TEST
36.8%
10%
0
0
Figure 8a. Human Body ESD Test Model
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 8a shows the Human Body Model, and Figure
8b 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 1.5kΩ resistor.
Applications Information
Typical Applications
The MAX13410E–MAX13415E transceivers are designed
for half-duplex, bidirectional data communications on
multipoint bus transmission lines. To minimize reflections,
terminate the line at both ends in its characteristic
impedance, and keep stub lengths off the main line as
short as possible. The slew-rate-limited MAX13410E/
MAX13412E/MAX13414E are more tolerant of imperfect
termination.
Typical Application Circuit for the
MAX13410E and MAX13411E
This application circuit shows the MAX13410E/
MAX13411E being used in an isolated application (see
Figure 9). The MAX13410E/MAX13411E use the industrystandard pin out but do not have a VREG output for
biasing external circuitry. The positive temperature coefficient (PTC) and transient voltage suppressor (TVS)
clamp circuit on the RS-485 outputs are intended to provide overvoltage fault protection and are optional based
on the requirements of the design.
tRL
TIME
tDL
CURRENT WAVEFORM
Figure 8b. Human Body Current Waveform
Typical Application Circuit for the
MAX13412E and MAX13413E
This application circuit shows the MAX13412E and
MAX13413E being used in an isolated application
where the AutoDirection feature is implemented to
reduce the number of optical isolators to two (see
Figure 10). The MAX13412E/MAX13413E provide a
VREG output that can be used to power external circuitry up to 20mA.
Typical Application Circuit for the
MAX13414E and MAX13415E
This application circuit shows the MAX13414E/
MAX13415E being used in an isolated application using
an unregulated power supply with three optical isolators
(see Figure 11). The MAX13414E/MAX13415E provide a
VREG output that can be used to power external circuitry
up to 20mA.
256 Transceivers on the Bus
The RS-485 standard specifies the load each receiver
places on the bus in terms of unit loads. An RS-485compliant transmitter can drive 32 one-unit load
receivers when used with a 120Ω cable that is terminated on both ends over a -7V to +12V common-mode
range. The MAX13410E–MAX13415E are specified as
1/8 unit loads. This means a compliant transmitter can
drive up to 256 devices of the MAX13410E–MAX13415E.
Reducing the common mode, and/or changing the characteristic impedance of the cable, changes the maximum number of receivers that can be used. Refer to the
TIA/EIA-485 specification for further details.
Proper Termination and Cabling/
Wiring Configurations
When the data rates for RS-485 are high relative to the
cable length it is driving, the system is subject to proper
______________________________________________________________________________________
19
MAX13410E–MAX13415E
RC
1MΩ
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
Rt
UNREGULATED ISOLATED
POWER SUPPLY
ISO_VCC
VSYS
+
MCU AND
RELATED
CIRCUITRY
ISO_VCC
N
RO
RE
DE
ISO_VCC
DI
1
LDO
R
8
ISO_VCC
0.1μF
2
7
3
6
4
VCC
5
D
B
A
GND
MAX13410E
MAX13411E
Rt
Figure 9. Typical Application Circuit for the MAX13410E/MAX13411E
transmission line design. In most cases, a single, controlled-impedance cable or trace should be used and
should be properly terminated on both ends with the
characteristic impedance of the cable/trace. RS-485
transceivers should be connected to the cable/ traces
with minimum-length wires to prevent stubs. Star configurations and improperly terminated cables can cause
data loss. Refer to the Application Notes section of the
Maxim website or to TIA/EIA publication TSB-89-A for
further information. While proper termination is always
desirable, in some cases, such as when data rates are
very low, it may be desirable and advantageous to not
properly terminate the cables. In such cases, it is up to
the designer to ensure that the improper termination
and resultant reflections (etc.) will not corrupt the data.
RE high. In shutdown, the devices draw 65µA (typ) of
supply current.
The devices are guaranteed not to enter shutdown if
DE is low (while RE is high) for less than 50ns. If the
inputs are in this state for at least 700ns, the devices
are guaranteed to enter shutdown.
Enable times tZH and tZL (see the switching characteristics table) assume the devices were not in a low-power
shutdown state. Enable times tZH(SHDN) and tZL(SHDN)
assume the devices were in shutdown state. It takes drivers and receivers longer to become enabled from lowpower shutdown mode (tZH(SHDN), tZL(SHDN)) than from
driver/receiver disable mode (tZH, tZL).
Reduced EMI and Reflections
The Telecommunications Industry Association (TIA) published the document TSB-89-A: Application Guidelines
for TIA/EIA-485-A, which is a good reference for determining maximum data rate vs. line length.
The MAX13410E/MAX13412E/MAX13414E feature
reduced slew-rate drivers that minimize EMI and reduce
reflections caused by improperly terminated cables,
allowing error-free data transmission up to 500kbps.
Low-Power Shutdown Mode
Low-power shutdown mode is initiated in the
MAX13410E/MAX13411E by driving DE low and driving
20
Line Length
Isolated RS-485 Interface
An isolated RS-485 interface electrically isolates different
nodes on the bus to protect the bus from problems due
to high common-mode voltages that exceed the RS-485
common-mode voltage range, conductive noise, and
______________________________________________________________________________________
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
MAX13410E–MAX13415E
Rt
ISO_VCC
UNREGULATED ISOLATED
POWER SUPPLY
VSYS
+
RO
MCU AND
RELATED
CIRCUITRY
1
R
LDO
8
VCC
0.1μF
ISO_VCC
RE
ISO_VCC
2
ISO_VCC
VREG
VSYS
CS
DETECT
CIRCUIT
7
3
6
1μF
DI
5
D
4
MAX13412E
MAX13413E
B
A
GND
ISO_VCC
Rt
Figure 10. Typical Application Circuit for the MAX13412E/MAX13413E
ground loops. The typical application circuits show an
isolated RS-485 interface using the MAX13410E–
MAX13415E. The transceiver is powered separately from
the controlling circuitry. The AutoDirection feature of the
MAX13412E/MAX13413E (see the AutoDirection Circuitry
section) requires only two optocouplers to electrically
isolate the transceiver.
An isolated RS-485 interface electrically isolates different nodes on the bus to protect the bus from problems
due to high common-mode voltages that exceed the
RS-485 common-mode voltage range. An isolated RS485 interface has two additional design challenges not
normally associated with RS-485 design. These are 1)
isolating the control signals and 2) getting isolated
power to the transceiver. Optical isolators are the most
common way of getting the control signals across the
isolation barrier.
Isolated power is typically done using a transformer in
either a push-pull or flyback configuration. The MAX845
is an example of an inexpensive, unregulated push-pull
converter (see Figure 12). While in theory, the output of
an unregulated push-pull converter is predictable, the
output voltage can vary significantly due to the non-ideal
characteristics of the transformer, load variations, and
temperature drift of the diodes, etc. Variances of ±20%
or more would not be uncommon. This would require the
addition of a linear regulator to get standard RS-485
transceivers to work. Since the MAX13410E–
MAX13415E have the linear regulator built in, this external regulator and its associated cost and size penalties
are not necessary. A nominal +7.5V output with a ±20%
tolerance would provide a +6V to +9V supply voltage.
This is well within the operating range of the
MAX13410E–MAX13415E. If the output tolerance is even
greater than ±20%, adjust the design of the power supply for a higher output voltage to ensure the minimum
input voltage requirements are met.
Flyback converters are typically regulated. A TL431 type
error amplifier and an optical isolator usually close the
loop. The MAX5021 is an example of a small, inexpensive, flyback controller (see Figure 13). While the primary output of the flyback converter is tightly regulated,
secondary outputs will not be. As with the unregulated
push-pull converter, the MAX13410E–MAX13415E are
ideally suited for use with these secondary outputs.
______________________________________________________________________________________
21
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
Rt
ISO_VCC
UNREGULATED ISOLATED
POWER SUPPLY
VSYS
ISO_VCC
+
VSYS
RO
MCU AND
RELATED
CIRCUITRY
DE/RE
ISO_VCC
LDO
R
8
2
7
3
6
VCC
0.1μF
B
ISO_VCC
VREG
CS
VSYS
1
1μF
DI
5
D
4
A
GND
MAX13414E
MAX13415E
Rt
Figure 11. Typical Application Circuit for the MAX13414E/MAX13415E
VIN
ON / OFF
4
6
SD
VCC
D1
5V
VSUPPLY
C1
CR1
1
VOUT
OUTPUT
5V AT 150mA
C2
MAX845
3
FREQUENCY
SELECT
FS
D2
GND1
GND2
2
7
VCC
8
T1
C3
VIN
MAX5021/
MAX5022
OPTO
NDRV
CR2
GND
CS
Figure 12. Using the MAX845 to Obtain an Isolated Power Supply
Figure 13. The MAX5021 and MAX5022 provide an isolated
power supply with tighter regulation due to feedback using an
opto-isolator coupler.
22
______________________________________________________________________________________
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
TOP VIEW
RO 1
+
RE 2
VREG
3
MAX13412E
MAX13413E
DI 4
*EP
8
VCC
7
B
RO
1
DE/RE
2
VREG
6
A
5
GND
3
+
MAX13414E
MAX13415E
DI 4
*EP
8
VCC
7
B
6
A
5
GND
SO
SO
*EXPOSED PAD CONNECTED TO GROUND
Ordering Information/Selector Guide (continued)
PART
PIN-PACKAGE
AutoDirection
DATA RATE (max)
5V LDO OUTPUT
MAX13412EESA+
8 SO-EP*
Yes
500kbps
Yes
MAX13413EESA+
8 SO-EP*
Yes
16Mbps
Yes
MAX13414EESA+**
8 SO-EP*
No
500kbps
Yes
MAX13415EESA+**
8 SO-EP*
No
16Mbps
Yes
Note: All devices operate over the -40°C to +85°C operating
temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
**Future product—contact factory for availability.
Package Information
Chip Information
PROCESS TECHNOLOGY: 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.
8 SO-EP
S8E+14
21-0111
______________________________________________________________________________________
23
MAX13410E–MAX13415E
Pin Configurations (continued)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
Revision History
REVISION
NUMBER
REVISION
DATE
0
11/07
1
8/09
DESCRIPTION
PAGES
CHANGED
Initial release.
—
Replaced Figure 9.
20
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.
24 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2009 Maxim Integrated Products
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