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MAX13415EESA+
Datasheet (Maxim)
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Datasheet MAX13410E, MAX13415EESA+ Datasheet (Maxim)

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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 V
REG
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.
Features
o Wide +6V to +28V Input Supply Range
o +5V Output Supplies Up to 20mA to External
Circuitry
o Internal LDO
o Low 65µA (typ) Shutdown Supply Current
o Extended ESD Protection
±15kV Human Body Model (MAX13412E/ MAX13413E) ±14kV Human Body Model (MAX13410E/ MAX13411E)
o 1/8-Unit Load, Allowing Up to 256 Transceivers on
the Bus
o -40°C to +85°C Operating Temperature Range
o Fail-Safe
o Slew-Rate Limited and Full-Speed Versions
o Up to 16Mbps Data Rate on Full-Speed Versions
Applications
-
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
________________________________________________________________
Maxim Integrated Products
1
19-1058; Rev 0; 11/07
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.
Ordering Information/Selector Guide
Note: All devices operate over the -40°C to +85°C operating temperature range.
+
Denotes a lead-free package.
*
EP = Exposed paddle.
Ordering Information/Selector Guide continued at end of data sheet.
PART PIN-PACKAGE AutoDirection DATA RATE (max) SLEW-RATE LIMITED PKG CODE
MAX13410EESA+ 8 SO-EP* No 500kbps Yes S8E+14
MAX13411EESA+ 8 SO-EP* No 16Mbps No S8E+14
Isolated RS-485 Interfaces
Utility Meters
Industrial Equipment
Telecomm Equipment
A
GNDDI
1
2
87V
CC
BRE
DE
RO
SO
TOP VIEW
3
4
6
5
MAX13410E MAX13411E
+
*EP
*EXPOSED PADDLE CONNECTED TO GROUND
Pin Configurations
Pin Configurations continued at end of data sheet.
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout Regulator and AutoDirection Control
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
(All voltages referenced to GND.) V
CC
.........................................................................-0.3V to +30V
RE, DE/RE, DE, DI, RO, V
REG
..................................-0.3V to +6V
A, B............................................................................-8V to +13V
Short-Circuit Duration (RO, A, B) to GND ................. Continuous
Continuous Power Dissipation (T
A
= +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
θ
JA
(Note 1)...................................................................52.0°C/W
θ
JC
(Note 1).....................................................................6.0°C/W
Lead Temperature (soldering, 10s) ................................+300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage V
CC
(Note 3) 6.0 28.0 V
VCC = +7.5V, I
LOAD
= 20mA 4.5 5 5.5
LDO Output Voltage V
REG
VCC = +28V, I
LOAD
= 0mA 4.5 5 5.5
V
LDO Output Current I
REG
VCC > +7.5V 20
mA
LDO Dropout Voltage V
DO
VCC = +5V, I
OUT
= 20mA 0.5 V
Minimum Bypass Capacitor on V
REG
C
S
Guaranteed by design, MAX13412E–MAX13415E
1µF
RE, DE = high/no load (MAX13410E/MAX13411E)
10
Supply Current I
CC
RE, DE/RE = high, DI = low/no load (MAX13412E–MAX13415E)
10
mA
Shutdown Current I
SHDN
DE = low, RE = high (MAX13410E/MAX13411E)
45 µA
Thermal-Shutdown Threshold T
TS
+150 °C
Thermal-Shutdown Threshold Hysteresis
T
TSH
15 °C
DRIVER
R
DIFF
= 100Ω, Figure 1 2.0 5.5
R
DIFF
= 54Ω, Figure 1 1.5 5.5Differential Driver Output V
OD
No load 5.5
V
Change in Magnitude of Differential Output Voltage
ΔV
ODRDIFF
= 100Ω or 54Ω, Figure 1 0.2 V
Driver Common-Mode Output Voltage V
OC
R
DIFF
= 100Ω or 54Ω, Figure 1 1 3 V
Change In Magnitude of Common­Mode Voltage
ΔV
OCRDIFF
= 100Ω or 54Ω, Figure 1 0.2 V
Input High Voltage V
IH
DI, DE, RE, DE/RE 2.0 V
Input Low Voltage V
IL
DI, DE, RE, DE/RE 0.8 V
Input Current I
IN
DI, DE, RE, DE/RE ±1 µA
Driver-Disable Threshold V
DT
TA = +25°C (MAX13412E/MAX13413E) 0.6 1.0 V
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.
ELECTRICAL CHARACTERISTICS
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC= +7.5V, CS= 1µF, and TA= +25°C.) (Note 2)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
_______________________________________________________________________________________ 3
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
0V < V
OUT
< +12V +250
Driver Short-Circuit Output Current I
OSD
-7V < V
OUT
< 0V -250
mA
(VCC - 1V) < V
OUT
< +12V 20
Driver Short-Circuit-Foldback Output Current
I
OSDF
-7V < V
OUT
< 0V -20
mA
RECEIVER
VIN = +12V 125
Input Current (A and B) I
A, B
RE, DE, DE/RE = GND, V
CC
= GND
V
IN
= -7V -100
µA
-7V < VCM < +12V (MAX13410E/MAX13411E)
-200 -50
Receiver Differential Threshold Voltage
V
TH
-7V < VLM < +12V (MAX13412E/MAX13413E)
-100 100
mV
Receiver Input Hysteresis ΔV
TH
VA + VB = 0V 15 mV
Output High Voltage V
OHIO
= -1mA, VA - VB > V
TH
V
REG
- 0.6 V
Output Low Voltage V
OL
IO = +1mA, VA - VB < -V
TH
0.4 V
Thr ee- S tate O utp ut C ur r ent at Recei ver I
OZR
0 < VO < V
REG
0.01 ±1 µA
Receiver-Input Resistance R
IN
-7V < VCM < +12V 96 kΩ
Receiver-Output Short-Circuit Current I
OSR
0V < V
RO
< V
REG
±8 ±95
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= T
MIN
to T
MAX
, 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
t
DPLH
150 1000
Driver Propagation Delay
t
DPHL
R
DIFF
= 54Ω, CL = 50pF,
Figures 2a and 3a
150 1000
ns
t
HL
250 900
Driver Differential Output Rise or Fall Time
t
LH
R
DIFF
= 54Ω, CL = 50pF,
Figures 2a and 3a
250 900
ns
Driver Differential Output Skew | t
DPLH
- t
DPHL
|
t
DSKEW
R
DIFF
= 54Ω, CL = 50pF,
Figures 2a and 3a
140 ns
Maximum Data Rate f
MAX
500 kbps
Driver Enable from Shutdown to Output High
t
DZH(SHDN
)
S2 closed, Figure 4, R
L
= 500Ω, CL = 100pF
11 µs
Driver Enable from Shutdown to Output Low
t
DZL(SHDN
)
S2 closed, Figure 4, R
L
= 500Ω, CL = 100pF
6µs
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC= +7.5V, CS= 1µF, and TA= +25°C.) (Note 2)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout Regulator and AutoDirection Control
4 _______________________________________________________________________________________
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Driver Enable to Output High t
DZH
S2 closed, Figure 4, R
L
= 500Ω, CL = 100pF
2500 ns
Driver Enable to Output Low t
DZL
S1 closed, Figure 4, R
L
= 500Ω, CL = 100pF
2500 ns
Driver Disable from Output High t
DHZ
S2 closed, Figure 4, R
L
= 500Ω, CL = 100pF
100 ns
Driver Disable from Output Low t
DLZ
S1 closed, Figure 4, R
L
= 500Ω, CL = 100pF
100 ns
Time to Shutdown t
SHDN
50 340 700 ns
RECEIVER
t
RPLH
200
Receiver Propagation Delay
t
RPHL
CL = 15pF (at RO), Figures 5 and 6
200
ns
Receiver Output Skew t
RSKEW
CL = 15pF (at RO), Figures 5 and 6 30 ns
Maximum Data Rate f
MAX
500 kbps
Receiver Enable to Output High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable to Output Low t
RZL
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from Low t
RLZ
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable from Shutdown to Output High
t
RZH(SHDN
)
S2 closed, Figure 7, CL = 15pF 14 µs
Receiver Enable from Shutdown to Output Low
t
RZL(SHDN
)
S1 closed, Figure 7, CL = 15pF 3.5 µs
SWITCHING CHARACTERISTICS–MAX13411E
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, 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
t
DPLH
50
Driver Propagation Delay
t
DPHL
R
DIFF
= 54Ω, CL = 50pF, Figures 2a
and 3a
50
ns
t
HL
15
Driver Differential Output Rise or Fall Time
t
LH
R
DIFF
= 54Ω, CL = 50pF, Figures 2a
and 3a
15
ns
Driver Differential Output Skew | t
DPLH
- t
DPHL
|
t
DSKEW
R
DIFF
= 54Ω, CL = 50pF, Figures 2a
and 3a
8ns
Maximum Data Rate f
MAX
16 Mbps
Driver Enable from Shutdown to Output High
t
DZH(SHDN
)
S2 closed, Figure 4, R
L
= 500Ω, CL = 100pF
11 µs
Driver Enable from Shutdown to Output Low
t
DZL(SHDN
)
S2 closed, Figure 4, R
L
= 500Ω, CL = 100pF
6µs
Driver Enable to Output High t
DZH
S2 closed, Figure 4, R
L
= 500Ω, CL = 100pF
70 ns
SWITCHING CHARACTERISTICS–MAX13410E (continued)
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC= +7.5V, CS= 1µF, and TA= +25°C.) (Note 2)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
_______________________________________________________________________________________ 5
SWITCHING CHARACTERISTICS–MAX13411E (continued)
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, 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 Low t
DZL
S1 closed, Figure 4, R
L
= 500Ω, CL = 100pF
70 ns
Driver Disable from Output High t
DHZ
S2 closed, Figure 4, R
L
= 500Ω, CL = 100pF
50 ns
Driver Disable from Output Low t
DLZ
S1 closed, Figure 4, R
L
= 500Ω, CL = 100pF
50 ns
RECEIVER
t
RPLH
75
Receiver Propagation Delay
t
RPHL
CL = 15pF (at RO), Figures 5 and 6
75
ns
Receiver Output Skew t
RSKEW
CL = 15pF (at RO), Figures 5 and 6 8 ns
Maximum Data Rate f
MAX
16 Mbps
Receiver Enable to Output High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable to Output Low t
RZL
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from High t
RZH
S2 closed, Figure 7 , CL = 15pF 50 ns
Receiver Disable Time from Low t
RLZ
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable from Shutdown to Output High
t
RZH(SHDN
)
S2 closed, Figure 7, CL = 15pF 14 µs
Receiver Enable from Shutdown to Output Low
t
RZL(SHDN
)
S1 closed, Figure 7, CL = 15pF 3.5 µs
SWITCHING CHARACTERISTICS–MAX13412E
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, 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
t
DPLH
200 1000
Driver Propagation Delay
t
DPHL
RL = 110Ω, CL = 50pF, Figures 2b and 3b
200 1000
ns
t
HL
250 900
Driver Differential Output Rise or Fall Time
t
LH
RL = 110Ω, CL = 50pF, Figures 2b and 3b
250 900
ns
Maximum Data Rate f
MAX
500 kbps
Driver Disable Delay t
DDD
RL = 110Ω, CL = 50pF, Figure 3b 2500 ns
RECEIVER
t
RPLH
200
Receiver Propagation Delay
t
RPHL
CL = 15pF, Figures 5 and 6
200
ns
Receiver Output Skew t
RSKEW
CL = 15pF, Figures 5 and 6 30 ns
Maximum Data Rate f
MAX
500 kbps
Receiver Enable to Output High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable to Output Low t
RZL
S1 closed, Figure 7, CL = 15pF 50 ns
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout Regulator and AutoDirection Control
6 _______________________________________________________________________________________
SWITCHING CHARACTERISTICS–MAX13412E (continued)
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, 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
Receiver Disable Time from Low t
RLZ
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable Delay t
RED
RL = 110Ω, CL = 50pF, Figure 3 2500 ns
SWITCHING CHARACTERISTICS–MAX13413E
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, 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
t
DPLH
50
Driver Propagation Delay
t
DPHL
RL = 110Ω, CL = 50pF, Figures 2b and 3b
50
ns
t
HL
15
Driver Differential Output Rise or Fall Time
t
LH
RL = 110Ω, CL = 50pF, Figures 2b and 3b
15
ns
Maximum Data Rate f
MAX
16 Mbps
Driver Disable Delay t
DDD
RL = 110Ω, CL = 50pF, Figure 3b 70 ns
RECEIVER
t
RPLH
80
Receiver Propagation Delay
t
RPHL
CL = 15pF, Figures 5 and 6
80
ns
Receiver Output Skew t
RSKEW
CL = 15pF, Figures 5 and 6 13 ns
Maximum Data Rate f
MAX
16 Mbps
Receiver Enable to Output High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable to Output Low t
RZL
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from Low t
RLZ
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable Delay t
RED
RL = 110Ω, Figure 3, CL = 50pF 70 ns
SWITCHING CHARACTERISTICS–MAX13414E
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, 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
t
DPLH
200 1000
Driver Propagation Delay
t
DPHL
R
DIFF
= 54Ω, CL = 50pF, Figures 2a
and 3a
200 1000
ns
t
HL
250 900
Driver Differential Output Rise or Fall Time
t
LH
R
DIFF
= 54Ω, CL = 50pF, Figures 2a
and 3a
250 900
ns
Driver Differential Output Skew | t
DPLH
- t
DPHL
|
t
DSKEW
R
DIFF
= 54Ω, CL = 50pF, Figures 2a
and 3a
140 ns
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
_______________________________________________________________________________________ 7
SWITCHING CHARACTERISTICS–MAX13414E (continued)
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, 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
Maximum Data Rate f
MAX
500 kbps
Driver Enable to Output High t
DZH
S2 closed, Figure 4, R
L
= 500Ω CL = 100pF
2500 ns
Driver Enable to Output Low t
DZL
S1 closed, Figure 4, R
L
= 500Ω CL = 100pF
2500 ns
Driver Disable from Output High t
DHZ
S2 closed, Figure 4, R
L
= 500Ω, CL = 100pF
100 ns
Driver Disable from Output Low t
DLZ
S1 closed, Figure 4, R
L
= 500Ω, CL = 100pF
100 ns
RECEIVER
t
RPLH
200
Receiver Propagation Delay
t
RPHL
CL = 15pF (at RO), Figures 5 and 6
200
ns
Receiver Output Skew t
RSKEW
CL = 15pF (at RO), Figures 5 and 6 30 ns
Maximum Data Rate f
MAX
500 kbps
Receiver Enable to Output High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable to Output Low t
RZL
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from Low t
RLZ
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
SWITCHING CHARACTERISTICS–MAX13415E
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, 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
t
DPLH
50
Driver Propagation Delay
t
DPHL
R
DIFF
= 54Ω, CL = 50pF, Figures 2a
and 3a
50
ns
t
HL
15
Driver Differential Output Rise or Fall Time
t
LH
R
DIFF
= 54Ω, CL = 50pF, Figures 2a
and 3a
15
ns
Driver Differential Output Skew | t
DPLH
- t
DPHL
|
t
DSKEW
R
DIFF
= 54Ω, CL = 50pF, Figures 2a
and 3a
8ns
Maximum Data Rate f
MAX
16 Mbps
Driver Enable to Output High t
DZH
S2 closed, Figure 4, R
L
= 500Ω, CL = 15pF
70 ns
Driver Enable to Output Low t
DZL
S1 closed, Figure 4, R
L
= 500Ω, CL = 15pF
70 ns
Driver Disable from Output High t
DHZ
S2 closed, Figure 4, R
L
= 500Ω, CL = 15pF
50 ns
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout Regulator and AutoDirection Control
8 _______________________________________________________________________________________
SWITCHING CHARACTERISTICS–MAX13415E (continued)
(VCC= +6.0V to +28V, TA= T
MIN
to T
MAX
, 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 Disable from Output Low t
DLZ
S1 closed, Figure 4, R
L
= 500Ω, CL = 15pF
50 ns
RECEIVER
t
RPLH
75
Receiver Propagation Delay
t
RPHL
CL = 15pF (at RO), Figures 5 and 6
75
ns
Receiver Output Skew t
RSKEW
CL = 15pF (at RO), Figures 5 and 6 8 ns
Maximum Data Rate f
MAX
16 Mbps
Receiver Enable to Output High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Receiver Enable to Output Low t
RZL
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from Low t
RLZ
S1 closed, Figure 7, CL = 15pF 50 ns
Receiver Disable Time from High t
RZH
S2 closed, Figure 7, CL = 15pF 50 ns
Note 2: CSis the compensation capacitor on V
REG
for the MAX13412E–MAX13415E versions. CSmust have an ESR value of 20mΩ or less.
Note 3: Parameters are guaranteed for +6.0V ≤ V
CC
≤ +28V.
8.0
6.0
4.0
2.0
0
-40 10-15 35 60 85
SUPPLY CURRENT
vs. TEMPERATURE
MAX13410E-15E toc01
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
NO LOAD
DE = HIGH
DE = LOW
0
10
5
20
15
30
25
35
021345
OUTPUT CURRENT
vs. RECEIVER OUTPUT HIGH VOLTAGE
MAX13410E-15E toc02
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
0
20
10
40
30
50
60
05
OUTPUT CURRENT
vs. RECEIVER OUTPUT LOW VOLTAGE
MAX13410E-15E toc03
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
2134
Typical Operating Characteristics
(VCC= +7.5V, TA= +25°C, unless otherwise noted.)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
_______________________________________________________________________________________
9
4.0
4.4
4.2
4.8
4.6
5.2
5.0
5.4
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
MAX13410E-15E toc04
TEMPERATURE (°C)
OUTPUT HIGH VOLTAGE (V)
-40 10-15 35 60 85
IO = +1mA
0
0.1
0.3
0.2
0.4
0.5
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
MAX13410E-15E toc05
TEMPERATURE (°C)
OUTPUT LOW VOLTAGE (V)
-40 10-15 35 60 85
IO = -1mA
80
60
40
20
0
021 345
DIFFERENTIAL OUTPUT CURRENT
vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX13410E-15E toc06
OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
MAX13410E-15E toc07
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
-40 10-15 35 60 85
R
DIFF
= 54Ω
0
40
20
80
60
100
120
-7 -5 -4 -3-6 -2 0-1 12345
OUTPUT CURRENT
vs. TRANSMITTER OUTPUT HIGH VOLTAGE
MAX13410E-15E toc08
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
0
40
20
80
60
100
120
OUTPUT CURRENT
vs. TRANSMITTER OUTPUT LOW VOLTAGE
MAX13410E-15E toc09
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
046281012
0
30
20
10
40
50
60
70
80
90
100
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX13410E-15E toc10
TEMPERATURE (°C
)
SHUTDOWN CURRENT (μA)
-40 10-15 35 60 85
0
200
100
400
300
600
500
700
DRIVER PROPAGATION vs. TEMPERATURE
(MAX13412E)
MAX13410E-15E toc11
TEMPERATURE (°C
)
DRIVER PROPAGATION DELAY (ns)
-40 10-15 35 60 85
RL = 110Ω
t
RPLH
t
RPHL
0
5
10
15
20
25
30
35
40
DRIVER PROPAGATION vs. TEMPERATURE
(MAX13413E)
MAX13410E-15E toc12
TEMPERATURE (°C
)
DRIVER PROPAGATION DELAY (ns)
-40 10-15 35 60 85
RL = 110Ω
t
RPHL
t
RPLH
Typical Operating Characteristics (continued)
(VCC= +7.5V, TA= +25°C, unless otherwise noted.)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout Regulator and AutoDirection Control
10 ______________________________________________________________________________________
60
45
30
15
0
-40 10-15 35 60 85
RECEIVER PROPAGATION vs.TEMPERATURE
(MAX13410E/MAX13412E)
MAX13410E-15E toc13
TEMPERATURE (°C)
RECEIVER PROPAGATION DELAY (ns)
t
RPHL
t
RPLH
60
45
30
15
0
-40 10-15 35 60 85
RECEIVER PROPAGATION vs.TEMPERATURE
(MAX13411E/MAX13413E)
MAX13410E-15E toc14
TEMPERATURE (°C)
RECEIVER PROPAGATION DELAY (ns)
t
RPHL
t
RPLH
DRIVER PROPAGATION (250kbps)
(MAX13412E)
MAX13410E-15E toc15
1μs/div
DI 2V/div
A - B 5V/div
DRIVER PROPAGATION (16kbps)
(MAX13413E)
MAX13410E-15E toc16
20ns/div
DI 2V/div
A - B 5V/div
RECEIVER PROPAGATION (16kbps)
(MAX13413E)
MAX13410E-15E toc17
20ns/div
A 2V/div
B 2V/div
RO 2V/div
DRIVING A LARGE CAPACITIVE LOAD 16nF
(19.2kbps) (MAX13412E)
MAX13410E-15E toc18
10μs/div
DI 2V/div
A - B 2V/div
DRIVING A LARGE CAPACITIVE LOAD 16nF
(1Mbps) (MAX13413E)
MAX13410E-15E toc19
400ns/div
DI 2V/div
A - B 5V/div
DRIVING A LARGE CAPACITIVE LOAD 16nF
(50kbps) (MAX13413E)
MAX13410E-15E toc20
1μs/div
DI 2V/div
A - B 2V/div
Typical Operating Characteristics (continued)
(VCC= +7.5V, TA= +25°C, unless otherwise noted.)
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
______________________________________________________________________________________ 11
V
OD
C
L
V
OC
A
B
R
DIFF
/ 2
R
DIFF
/ 2
Figure 1. Driver DC Test Load
1.5V
1.5V
0
DI
B
A
t
DPLH
t
DPHL
1/2 V
O
1/2 V
O
V
O
10%
90%
10%
90%
0
V
O
-V
O
V
DIFF
t
DSKEW
= |t
DPLH
- t
DPHL
|
V
DIFF
= VA - V
B
t
HLt
LH
5V
f = 1MHz, tLH ≤ 3ns, tHL ≤ 3ns
Figure 3a. Driver Propagation Delays
Test Circuits and Waveforms
A
B
DE
DI
5V
R
DIFF
C
L
V
ID
Figure 2a. Driver-Timing Test Circuit
A
B
DI
R
L
V
ID
R
L
V
REG
GND
C
L
Figure 2b. Driver-Timing Test Circuit
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout Regulator and AutoDirection Control
12 ______________________________________________________________________________________
Test Circuits and Waveforms (continued)
1.5V
1.5V
0
DI
B
A
t
DPLH
t
DPHL
1/2 V
O
1/2 V
O
V
O
t
DDD
, t
RED
RO
(RO PULLED LOW)
10%
90%
10%
90%
0
V
O
O
-V
O
V
DIFF
V
DIFF
= VA - V
B
t
HL
t
LH
f = 1MHz, tLH ≤ 3ns, tHL ≤ 3ns
5V
RE = V
CC
Figure 3b. Driver Propagation Delays
1.5V
1.5V
A, B
0
0
OUTPUT NORMALLY LOW
DE
OUTPUT NORMALLY HIGH
t
DZL(SHDN)
t
DZH(SHDN)
t
DLZ
t
DHZ
2.3V
2.3V
V
OL
+ 0.5V
V
OH
+ 0.5V
V
OH
A, B
V
OL
V
CC
OUTPUT
UNDER TEST
5V
C
L
S
1
S
2
500Ω
Figure 4. Driver Enable and Disable Times
V
ID
A
B
R
RECEIVER OUTPUT
ATE
Figure 5. Receiver-Propagation-Delay Test Circuit
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
______________________________________________________________________________________ 13
Test Circuits and Waveforms (continued)
1.5V
1.5V
1V
-1V
f = 1MHz, t
LH
≤ 3ns, tHL ≤ 3ns
t
RPHL
t
RSKEW
= | t
RPHL
- t
RPLH |
t
RPLH
V
OH
V
OL
RO
A
B
Figure 6. Receiver Propagation Delays
1.5V
1.5V
RO
0
0
OUTPUT NORMALLY LOW
RO
OUTPUT NORMALLY HIGH
t
RZH(SHDN)
, t
RZH
t
RHZ
t
RHZ
2.3V
2.3V V
OH
+ 0.5V
V
OH
+ 0.5V
DI = 0V
RE
V
REG
V
REG
V
REG
0
t
RZL(SHDN)
, t
RZL
5V
C
L
15pF
S
1
S
2
1kΩ
RO
Figure 7. Receiver Enable and Disable Times
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout Regulator and AutoDirection Control
14 ______________________________________________________________________________________
Pin Description
PIN
MAX13410E/
MAX13411E
MAX13412E/
MAX13413E
MAX13414E/
MAX13415E
NAME FUNCTION
1—1RO
Receiver Output. When receiver is enabled and V
A
- VB ≥ -50mV,
RO is high. If V
A
- VB ≤ -200mV, RO is low. Note: RO is referenced to
the LDO output (V
REG
).
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
D r i ver Outp ut E nab l e. D r i ve D E l ow to p ut the d r i ver outp ut i n thr ee- state. D r i ve D E hi g h to enab l e the d r i ver .
444DI
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.
5 5 5 GND Ground
6 6 6 A Noninverting Receiver Input and Noninverting Driver Output
7 7 7 B Inverting Receiver Input and Inverting Driver Output
888V
CC
Positive Supply. Bypass VCC with a 0.1µF ceramic capacitor to GND.
—1—RO
Receiver Output. When receiver is enabled and V
A
- VB ≥ -100mV,
RO is high. If V
A
- VB ≤ -100mV, RO is low. Note: RO is referenced to
the LDO output (V
REG
).
—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 3V
REG
LDO Output. V
REG
is fixed at +5V. Bypass V
REG
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
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.
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
______________________________________________________________________________________ 15
Function Tables for the MAX13410E/MAX13411E
TRANSMITTING
INPUT OUTPUT
RE DE DI B A
X11 0 1
X10 1 0
0 0 X High impedance High impedance
1 0 X High impedance (shutdown)
RECEIVING
INPUT OUTPUT
RE DE A - B RO
0X > -50mV 1
0X < -200mV 0
0 X Open/Short 1
1 1 X High impedance
10 X
High impedance
(shutdown)
X
= Don’t care, shutdown mode, driver, and receiver outputs are in high impedance.
Function Tables for the MAX13414E/MAX13415E
TRANSMITTING
INPUT OUTPUT
DE/RE DI B A
0 X High impedance High impedance
11 0 1
10 1 0
RECEIVING
INPUT OUTPUT
DE/RE A - B RO
0 > -50mV 1
0 < -200mV 0
0 Open/Short 1
1 X High impedance
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 > V
DT
ACTION A B
0 X Turn driver ON 0 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
X
= Don’t care, shutdown mode, driver, and receiver outputs are in 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
MAX13410E–MAX13415E
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 V
REG
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 V
REG
output. This allows additional external circuitry to be powered without the need for additional external regulators. The V
REG
output can
source up to 20mA.
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:
T
DIE
= [(
θ
JC
+
θ
CA
) x P
DISS
] + T
AMBIENT
, where
T
DIE
= Temperature of the Die
θ
JC
= 6.0°C/W = Junction-to-Case Thermal Resist-
ance
θ
CA
= Case-to-Ambient Thermal Resistance
θ
JA
=
θ
JC
+
θ
CA
= 52.0°C/W = Junction-to-Ambient
Thermal Resistance
P
DISS
= (ICC- VCC) + [(VCC- V
REG
) x I
REG
)] + [(VCC-
VOD) x I
DRIVER
] = Power Dissipation of the Part
T
AMBIENT
= Ambient Temperature
VCC= Voltage on the VCCInput
ICC= Current in to V
CC
V
REG
= Voltage on the V
REG
Output
I
REG
= Current Drawn from the V
REG
Output
VOD= Voltage at the Driver Output (|VA- VB|)
I
DRIVER
= 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:
•V
CC
•I
REG
•
θ
CA
Measuring the VCCCurrent
Measured current at the VCCpin 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 V
REG
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
16 ______________________________________________________________________________________
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.
θθ
CA
θ
CA
is the thermal resistance from case to ambient and
is independent of the MAX13410E–MAX13415E.
θ
CA
is
primarily a characteristic of the circuit-board design. The
largest contributing factor of
θ
CA
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
θ
JC
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
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
______________________________________________________________________________________ 17
Functional Diagrams
Functional Diagram for the MAX13410E/MAX13411E/MAX13414E/MAX13415E
A
GNDDI
1
2
87V
CC
BRE
DERO3
4
6
5
R
D
+
LDO
MAX13410E MAX13411E
A
GNDDI
1
2
87V
CC
BDE/RE
V
REG
RO
3
4
6
5
R
D
+
LDO
MAX13414E MAX13415E
Functional Diagram for the MAX13412E/MAX13413E
V
CC
8
-
+
+
-
STATE
MACHINE
D
R
A
B
RE
DI
RO
COM
V
REG
RE
GND
V
REG
1
3
2
4
6
7
5
RI
DI
V
DT
MAX13412E MAX13413E
V
REG
LDO
V
REG
DE
MAX13410E–MAX13415E
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
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
18 ______________________________________________________________________________________
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 V
REG
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.
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 V
REG
output that can be used to power external circuit-
ry 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 V
REG
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 prop-
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
______________________________________________________________________________________ 19
CHARGE-CURRENT-
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE CAPACITOR
C
s
100pF
R
C
1MΩ
R
D
1500Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
Figure 8a. Human Body ESD Test Model
IP 100%
90%
36.8%
t
RL
TIME
t
DL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE)
I
r
10%
0
0
AMPS
Figure 8b. Human Body Current Waveform
MAX13410E–MAX13415E
er 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. RS­485 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
Applications
section of the Maxim website or to TIA/EIA publication TSB89 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.
Reduced EMI and Reflections
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
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 t
ZH
and tZL(see the
Switching Character-
istics
table) assume the devices were not in a low-power
shutdown state. Enable times t
ZH(SHDN)
and t
ZL(SHDN)
assume the devices were in shutdown state. It takes dri­vers and receivers longer to become enabled from low­power shutdown mode (t
ZH(SHDN)
, t
ZL(SHDN)
) than from
driver/receiver disable mode (tZH, tZL).
Line Length
The Telecommunications Industry Association (TIA) pub­lished the document TSB-89:
Application Guidelines for
TIA/EIA-485-A
, which is a good reference for determin-
ing maximum data rate vs. 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
20 ______________________________________________________________________________________
A
GND
DI
1
2
8
7
V
CC
B
DE
RO
3
4
6
5
R
D
+
MAX13410E MAX13411E
LDO
RE
ISO_V
CC
ISO_V
CC
ISO_V
CC
MCU AND
RELATED
CIRCUITRY
V
SYS
V
SYS
V
SYS
ISO_V
CC
UNREGULATED ISOLATED
POWER SUPPLY
R
t
R
t
0.1μF
Figure 9. Typical Application Circuit for the MAX13410E/MAX13411E
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.
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
A
GND
DI
1
2
8
7
V
CC
B
V
REG
RO
3
4
6
5
R
D
+
MAX13412E MAX13413E
LDO
RE
ISO_V
CC
ISO_V
CC
MCU AND
RELATED
CIRCUITRY
V
SYS
V
SYS
0.1μF
R
t
R
t
ISO_V
CC
ISO_V
CC
1μF
C
S
DETECT
CIRCUIT
ISO_V
CC
UNREGULATED ISOLATED
POWER SUPPLY
Figure 10. Typical Application Circuit for the MAX13412E/MAX13413E
______________________________________________________________________________________ 21
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout Regulator and AutoDirection Control
22 ______________________________________________________________________________________
A
GND
DI
1
2
8
7
V
CC
B
V
REG
RO
3
4
6
5
R
D
+
MAX13414E MAX13415E
LDO
DE/RE
ISO_V
CC
ISO_V
CC
ISO_V
CC
MCU AND
RELATED
CIRCUITRY
V
SYS
V
SYS
V
SYS
R
t
R
t
C
S
1μF
ISO_V
CC
0.1μF
UNREGULATED ISOLATED
POWER SUPPLY
Figure 11. Typical Application Circuit for the MAX13414E/MAX13415E
MAX845
D1
D2FS
GND1 GND2
V
CC
1
8
46
27
3
V
IN
SD
FREQUENCY
SELECT
C2
C1
C3
5V AT 150mA
OUTPUT
5V
ON / OFF
T1
CR2
CR1
Figure 12. Using the MAX845 to Obtain an Isolated Power Supply
MAX5021/
MAX5022
V
OUT
V
SUPPLY
OPTO NDRV
CS
V
CC
V
IN
GND
Figure 13. The MAX5021 and MAX5022 provide an isolated power supply with tighter regulation due to feedback using an opto-isolator coupler.
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout
Regulator and AutoDirection Control
______________________________________________________________________________________ 23
Ordering Information/Selector Guide (continued)
Note: All devices operate over the -40°C to +85°C operating temperature range.
+
Denotes a lead-free package.
*
EP = Exposed paddle.
**
Future product—contact factory for availability.
PART PIN-PACKAGE AutoDirection DATA RATE (max) SLEW-RATE LIMITED PKG CODE
MAX13412EESA+ 8 SO-EP* Yes 500kbps Yes S8E+14
MAX13413EESA+ 8 SO-EP* Yes 16Mbps No S8E+14
MAX13414EESA+** 8 SO-EP* No 500kbps Yes S8E+14
MAX13415EESA+** 8 SO-EP* No 16Mbps No S8E+14
TOP VIEW
A
GNDDI
1
2
87V
CC
BRE
V
REG
RO
SO
3
4
6
5
MAX13412E MAX13413E
+
*EP
A
GNDDI
1
2
87V
CC
BDE/RE
V
REG
RO
SO
3
4
6
5
MAX13414E MAX13415E
+
*EP
*EXPOSED PADDLE CONNECTED TO GROUND
Pin Configurations (continued)
Chip Information
PROCESS TECHNOLOGY: BiCMOS
MAX13410E–MAX13415E
RS-485 Transceiver with Integrated Low-Dropout Regulator and AutoDirection Control
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
© 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
SPRINGER
8L, SOIC EXP. PAD.EPS
C
1
1
21-0111
PACKAGE OUTLINE 8L SOIC, .150" EXPOSED PAD
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages
.)
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