MAX14943 isolated RS-485/PROFIBUS DP transceiver

EVALUATION KIT AVAILABLE
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
General Description
The MAX14943 isolated RS-485/PROFIBUS DP transceiver
provides 5000VRMS (60s) of galvanic isolation between
the cable side (RS-485 driver/receiver side) and the UART
side of the device. Isolation improves communication by
breaking ground loops and reduces noise when there are
large differences in ground potential between ports. This
device allows for robust communication up to 20Mbps.
The device includes an integrated 450kHz transformer
driver for power transfer to the cable side of the transceiver
using an external transformer. An integrated LDO provides
a simple and space-efficient architecture for providing
power to the cable side of the IC.
The device includes one half-duplex driver/receiver channel.
The receiver is 1/4-unit load, allowing up to 128 transceivers
on a common bus.
Integrated true fail-safe circuitry ensures a logic-high on
the receiver output when inputs are shorted or open.
Undervoltage lockout disables the driver when cable-side
or UART-side power supplies are below functional levels.
The driver outputs/receiver inputs are protected from
±35kV electrostatic discharge (ESD) to GNDB on the
cable side, as specified by the Human Body Model (HBM).
The MAX14943 is available in a 16-pin wide-body SOIC
package and operates over the -40°C to +105°C temperature
range.
Benefits and Features
●● High Integration Simplifies Designs
• Integrated LDO for Cable-Side Power
• Integrated Transformer Driver for Power Transfer
to Cable Side Has Up to 80% Efficiency at 150mA
Load
●● High-Performance Transceiver Enables Flexible
Designs
• Compliant with RS-485 and EIA 61158-2 Type 3
PROFIBUS DP Standards
• 20Mbps (max) Data Rate
• Up to 128 Devices on the Bus
●● Integrated Protection for Robust Communication
• ±35kV ESD (HBM) on Driver Outputs/Receiver
Inputs
• 5kVRMS Withstand Isolation Voltage for 60s (VISO)
• 1200VPEAK Maximum Repetitive Peak-Isolation
Voltage (VIORM)
• 848VRMS Maximum Working-Isolation Voltage
(VIOWM)
• > 30 Years Lifetime at Rated Working Voltage
• Withstands ±10kV Surge per IEC 61000-4-5
• Thermal Shutdown
Functional Diagram
Applications
●●
●●
●●
●●
Industrial Automation Equipment
Programmable Logic Controllers
HVAC
Power Meters
Safety Regulatory Approvals Pending
●● UL According to UL1577
●● cUL According to CSA Bulletin 5A
●● VDE 0884-10
VDDA
MAX14943
XFMR
DRIVER
19-7653; Rev 0; 6/15
LDO
VDDB
RE
RXD
TXD
A
B
DE
DEM
GNDA
The PROFIBUS logo is a registered trademark of PROFIBUS
and PROFINET International (PI).
VLDO
TD1 TD2
RS-485
Transceiver
MAX14943
GNDB
Ordering Information appears at end of data sheet.
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Absolute Maximum Ratings
VDDA to GNDA ........................................................-0.3V to +6V
VDDB to GNDB.........................................................-0.3V to +6V
VLDO to GNDB.......................................................-0.3V to +16V
TD1, TD2 to GNDA ...............................................-0.3V to +12V
TXD, DE, RE, RXD to GNDA ..................................-0.3V to +6V
DEM to GNDB .........................................................-0.3V to +6V
A, B to GNDB............................................................-8V to +13V
TD1, TD2 Continuous Current............................................±1.4A
Short-Circuit Duration (RXD to GNDA, A, B, DEM,
VDDB to GNDB).....................................................Continuous
Continuous Power Dissipation (TA = +70°C)
16-pin wide-body SOIC
(derate 14.1mW/°C above +70°C)........................... 1126.8mW
Operating Temperature Range.......................... -40°C to +105°C
Junction Temperature.......................................................+150°C
Storage Temperature Range............................. -65°C to +150°C
Lead Temperature (soldering, 10s).................................. +300°C
Soldering Temperature (reflow)........................................+260°C
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.
Package Thermal Characteristics (Note 1)
Junction-to-Ambient Thermal Resistance (θJA)...............71°C/W
Junction-to-Case Thermal Resistance (θJC)....................23°C/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
DC Electrical Characteristics
(VDDA - VGNDA = 3.0V to 5.5V, VDDB - VGNDB = 4.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA
- VGNDA = 3.3V, VDDB - VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
POWER
Supply Voltage
Supply Current
Undervoltage-Lockout
Threshold
Undervoltage-Lockout
Threshold Hysteresis
VDDA
3.0
5.5
VDDB
4.5
5.5
IDDA
VDDA = 5V, DE = high, RE = TXD =
low, RXD unconnected, no bus load,
TD1/TD2 unconnected
4.7
IDDB
DE = high, RE = TXD = low, RXD unconnected, no bus load, VDDB = 5V
7.7
12.5
VUVLOA
VUVLOB
VUVHYSTA
V
7.7
mA
RE, RXD, DE, TXD, VDDA rising
1.50
1.58
1.65
TD1/TD2 driver, VDDA rising
2.55
2.7
2.85
VDDB rising
2.55
2.7
2.85
RE, RXD, DE, TXD
50
TD1/TD2 driver
200
VUVHYSTB
V
mV
200
TRANSFORMER DRIVER
Output Resistance
RO
TD1, TD2 Current Limit
ILIM
Switching Frequency
fSW
Duty Cycle
Crossover Dead Time
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TD1/TD2 = low, IOUT = 300mA
0.6
1.5
4.5V ≤ VDDA ≤ 5.5V
540
785
1300
3.0V ≤ VDDA ≤ 3.6V
485
730
1170
350
450
550
Ω
mA
kHz
D
50
%
tDEAD
50
ns
Maxim Integrated │ 2
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
DC Electrical Characteristics (continued)
(VDDA - VGNDA = 3.0V to 5.5V, VDDB - VGNDB = 4.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA
- VGNDA = 3.3V, VDDB - VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
LDO Supply Voltage
VLDO
Relative to GNDB, LDO is on (Note 4)
4.68
LDO Supply Current
ILDO
DE = high, TXD = low, no bus load,
VLDO = 5.5V
LDO Output Voltage
VDDB
TYP
MAX
UNITS
14
V
7.8
12.9
mA
5
5.5
V
LDO
4.5
LDO Current Limit
300
mA
Load Regulation
VLDO = 5.68V, ILOAD = 20mA to 40mA
0.19
1.7
mV/mA
Line Regulation
VLDO = 5.68V to 14V, ILOAD = 20mA
0.12
1.8
mV/V
Dropout Voltage
VLDO = 4.68V, IDDB = 120mA
100
180
mV
Load Capacitance
Nominal value (Note 5)
1
10
µF
0.7 x
VDDA
LOGIC INTERFACE (TXD, RXD, DE, RE, DEM)
Input High Voltage
VIH
RE, TXD, DE to GNDA
Input Low Voltage
VIL
RE, TXD, DE to GNDA
VHYS
RE, TXD, DE to GNDA
220
mV
Input Capacitance
CIN
RE, TXD, DE, f = 1MHz
2
pF
Input Pullup Current
IPU
TXD
-10
-4.5
-1.5
µA
Input Pulldown Current
IPD
DE, RE
1.5
4.5
10
µA
Input Hysteresis
Output Voltage High
Output Voltage Low
VOH
VOL
Short-Circuit Output Pullup
Current
ISH_PU
Short-Circuit Output Pulldown
Current
ISH_PD
Three-State Output Current
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IOZ
V
0.8
RXD to GNDA, IOUT = -4mA
VDDA
-0.4
DEM to GNDB, IOUT = -4mA
VDDB
-0.4
V
RXD to GNDA, IOUT = 4mA
0.40
DEM to GNDB, IOUT = 4mA
0.40
0V ≤ VRXD ≤ VDDA, VA - VB > -50mV,
RE = low
-42
0V ≤ VDEM ≤ VDDB, DE = high
-42
+40
0V ≤ VDEM ≤ VDDB, DE = low
+40
-1
V
mA
0V ≤ VRXD ≤ VDDA, VA - VB < -200mV,
RE = low
0V ≤ VRXD ≤ VDDA, RE = high
V
+1
mA
µA
Maxim Integrated │ 3
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
DC Electrical Characteristics (continued)
(VDDA – VGNDA = 3.0V to 5.5V, VDDB – VGNDB = 4.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at
VDDA – VGNDA = 3.3V, VDDB – VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Differential Driver Output
|VOD|
Differential Driver Peak-to-Peak
Output
VODPP
Change in Magnitude of
Differential Driver Output Voltage
ΔVOD
Driver Common-Mode Output
Voltage
Change in Magnitude of
Common-Mode Voltage
Driver Short-Circuit Output
Current
Driver Short-Circuit Foldback
Output Current
VOC
ΔVOC
IOSD
IOSDF
RECEIVER
RL = 54Ω, TXD = high or low,
DE = high, Figure 1a
2.1
RL = 100Ω, TXD = high or low,
DE = high, Figure 1a
2.9
-7V ≤ VCM ≤ +12V, Figure 1b
1.5
5
Figure 2 (Note 6)
4.0
6.8
V
RL = 54Ω, Figure 1b (Note 7)
-0.2
+0.2
V
3
V
+0.2
V
RL = 54Ω, Figure 1a
RL = 54Ω, Figure 1a (Note 7)
1.8
-0.2
GNDB ≤ VOUT ≤ +12V, output low
(Note 8)
+250
mA
-7V ≤ VOUT ≤ VDDB, output high
(Note 8)
-250
(VDDB – 1V) ≤ VOUT ≤ +12V,
output low (Notes 5, 8)
+15
mA
-7V ≤ VOUT ≤ +1V, output high
(Note 5, 8)
Input Current (A and B)
IA, IB
DE = GNDA,
VDDB = GNDB
or 5.5V
Receiver Differential Threshold
Voltage
VTH
-7V ≤ VCM ≤ +12V
-15
VIN = +12V
VIN = -7V
Receiver Input Hysteresis
ΔVTH
Receiver Input Resistance
RIN
-7V ≤ VCM ≤ +12V, DE = low
CA,B
Measured between A and B,
DE = RE = GNDA at 6MHz
Differential Input Capacitance
V
+250
-200
-200
VCM = 0V
-125
15
48
-50
µA
mV
mV
kΩ
8
pF
+160
°C
15
°C
PROTECTION
Thermal-Shutdown Threshold
TSHDN
Thermal-Shutdown Hysteresis
THYST
ESD Protection
(A and B Pins to GNDB)
ESD Protection (All Other Pins)
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Temperature Rising
Human Body Model
±35
IEC 61000-4-2 Air Gap Discharge
±12
IEC 61000-4-2- Contact Discharge
±10
Human Body Model
±4
kV
kV
Maxim Integrated │ 4
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Switching Electrical Characteristics
(VDDA - VGNDA = 3.0V to 5.5V, VDDB - VGNDB = 4.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDDA
- VGNDA = 3.3V, VDDB - VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C.) (Note 5)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DYNAMIC
Common Mode Transient
Immunity
CMTI
Glitch Rejection
(Note 9)
TXD, DE, RXD
35
10
17
kV/μs
29
ns
RL = 54Ω, CL = 50pF, Figure 3 and
tDPLH, tDPHL
Figure 4
68
ns
DRIVER
Driver Propagation Delay
Differential Driver Output Skew
|tDPLH - tDPHL|
tDSKEW
RL = 54Ω, CL = 50pF, Figure 3 and
Figure 4
6
ns
Driver Differential Output Rise
or Fall Time
tLH, tHL
RL = 54Ω, CL = 50pF, Figure 3 and
Figure 4
15
ns
Maximum Data Rate
DRMAX
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
RECEIVER
Receiver Propagation Delay
20
Mbps
tDZH
tDZL
RL = 500Ω, CL = 50pF, Figure 5
88
ns
RL = 500Ω, CL = 50pF, Figure 6
88
ns
tDLZ
tDHZ
RL = 500Ω, CL = 50pF, Figure 6
80
ns
RL = 500Ω, CL = 50pF, Figure 5
80
ns
CL = 15pF, Figure 7 and Figure 8
tRPLH, tRPHL
(Note 10)
68
ns
CL = 15pF, Figure 7 and Figure 8
(Note 10)
6
ns
Receiver Output Skew
tRSKEW
Maximum Data Rate
Receiver Enable to Output
High
DRMAX
20
Mbps
tRZH
RL = 1kΩ, CL = 15pF, S2 closed, Figure 9
20
ns
Receiver Enable to Output Low
tRZL
RL = 1kΩ, CL = 15pF, S2 closed, Figure 9
30
ns
Receiver Disable Time from
Low
tRLZ
RL = 1kΩ, CL = 15pF, S1 closed,
Figure 9
20
ns
Receiver Disable Time from
High
tRHZ
RL = 1kΩ, CL = 15pF, S2 closed,
Figure 9
20
ns
Note 2: All devices are 100% production tested at TA = +25°C. Specifications over temperature are guaranteed by design.
Note 3: All currents into the device are positive. All currents out of the device are negative. All voltages are referenced to their
respective ground (GNDA or GNDB), unless otherwise noted.
Note 4:VLDO max indicates voltage capability of the circuit. Power dissipation requirements may limit VLDO max to a lower value.
Note 5: Not production tested. Guaranteed by design.
Note 6:VODPP is the difference in VOD when TXD is high and when TXD is low.
Note 7: ΔVOD and ΔVOC are the changes in VOD and VOC, respectively, when the TXD input changes state.
Note 8: The short-circuit output current applies to the peak current just prior to foldback-current limiting. The short-circuit foldback
output current applies during current limiting to allow a recovery from bus contention. See TOC6 and TOC7 in the Typical
Operating Characteristics section..
Note 9: CMTI is the maximum sustainable common-mode voltage slew rate while maintaining the correct output states. CMTI
applies to both rising and falling common-mode voltage edges. Tested with the transient generator connected between
GNDA and GNDB. ΔVCM = 1kV.
Note 10:Capacitive load includes test probe and fixture capacitance.
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Maxim Integrated │ 5
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Insulation Characteristics
PARAMETER
Partial Discharge Test Voltage
SYMBOL
VPR
CONDITIONS
VALUE
UNITS
Method B1 = VIORM x 1.875
(t = 1s, partial discharge < 5pC)
2250
VP
Maximum Repetitive Peak Isolation
Voltage
VIORM
(Note 11)
1200
V
Maximum Working Isolation Voltage
VIOWM
(Note 11)
848
VRMS
Maximum Transient Isolation Voltage
VIOTM
t = 1s
8400
VP
Maximum Withstand Isolation Voltage
VISO
t = 60s, f = 60Hz (Note 11, 12)
5000
Maximum Surge Isolation Voltage
10
VRMS
kV
>109
Ω
f = 1MHz
2
pF
CPG
Wide SOIC
8
mm
CLR
Wide SOIC
8
mm
0.015
mm
VISOM
Basic insulation
Insulation Resistance
RS
TA = +150°C, VIO = 500V
Barrier Capacitance Input-to-Output
CIO
Minimum Creepage Distance
Minimum Clearance Distance
Internal Clearance
Comparative Tracking Resistance Index
Distance through insulation
CTI
Material Group II (IEC 60112)
Climatic Category
Pollution Degree (DIN VDE 0110, Table 1)
575
40/125/21
2
Note 11:VIORM, VIOWM, and VISO are defined by the IEC 60747-5-5 standard.
Note 12:Product is qualified VISO for 60 seconds. 100% production tested at 120% of VISO for 1 second.
Regulatory Information
UL
The MAX14943 is certified under UL1577. For more details, see File E351759.
Rate up to 5000VRMS isolation voltage for basic insulation.
cUL
Pending
VDE
Pending
TUV
Pending
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Maxim Integrated │ 6
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
375 Ω
A
A
RL
2
VOD
VOD
60 Ω
+ VCM
-
VOC
RL
2
B
B
375 Ω
(b)
(a)
Figure 1. Driver DC Test Load
VDDB
VDDA
195Ω
A
A
TXD
TXD
110Ω
VODPP
B
VOD
RL
CL
B
195Ω
GNDA
GNDA
GNDB
Figure 2. VODPP Swing Under PROFIBUS Equivalent Load Test
Figure 3. Driver Timing Test Circuit
f = 1MHz, tLH P 3ns, tHL P 3ns
VDDA
50%
TXD
50%
GNDA
1/2 VO
tDPHL
tDPLH
B
A
1/2 VO
VO
VDIFF = VA - VB
VO
80%
80%
VDIFF
0
20%
20%
tLH
-VO
tHL
tDSKEW = |tDPLH - tDPHL|
Figure 4. Driver Propagation Delays
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Maxim Integrated │ 7
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
A
GNDA OR VDDA TXD D
B
DE
S1
VDDA
OUT
CL
50pF
DE
RL = 500I
50%
250mV
OUT
GENERATOR
50%
GNDB
50I
GNDA
tDZH
tDHZ
VOH
GNDB
GNDA
Figure 5. Driver Enable and Disable Times (tDZH, tDHZ)
VDDB
GNDA OR VDDA TXD D
A
B
DE
GENERATOR
RL = 500I
S1
OUT
CL = 50pF
GNDB
50I
GNDA
VDDA
DE
50%
GNDA
tDZL
tDLZ
VDDB
50%
OUT
250mV
VOL
Figure 6. Driver Enable and Disable Times (tDZL, tDLZ)
A
ATE
R
VID
RECEIVER
OUTPUT
B
Figure 7. Receiver Propagation-Delay Test Circuit
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Maxim Integrated │ 8
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
t = 1MHz, tLH P 3ns, tHL P 3ns
A
1V
B
-1V
tRPHL
tRPLH
VDDA
2
RXD
VOH
VDDA
2
VOL
tRSKEW = |tRPHL - tRPLH|
Figure 8. Receiver Propagation Delays
+1.5V
S3
-1.5V
VID
GNDB
GENERATOR
R
RE
RXD
RL
1kI
S1
VDDA
S2
CL
15pF
GNDA
50I
GNDA
VDDA
VDDA
50%
RE
S1 OPEN
S2 CLOSED
GNDA S3 = +1.5V
50%
RE
GNDA
tRZL
tRZH
VOH
VDDA
2
GNDA
RXD
VDDA
50%
RE
VDDA
2
RXD
S1 OPEN
S2 CLOSED
S3 = +1.5V
VDDA
RE
50%
GNDA
GNDA
RXD
VDDA
VOL
S1 CLOSED
S2 OPEN
S3 = -1.5V
tRLZ
tRHZ
0.25V
S1 CLOSED
S2 OPEN
S3 = -1.5V
VDDA
VOH
RXD
GNDA
0.25V
VOL
Figure 9. Receiver Enable and Disable Times
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Maxim Integrated │ 9
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Typical Operating Characteristics
(VDDA - VGNDA = 3.3V, VDDB - VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C, unless otherwise noted.)
VDDA SUPPLY CURRENT
vs. TEMPERATURE
8
toc01
7
4
OUTPUT CURRENT (mA)
5
8
6
3
4
2
NO LOAD
NO SWITCHING
TD1/TD2 UNCONNECTED
1
-45 -30 -15
0
15
30
45
60
75
2
0
90 105
-45 -30 -15
0
15
30
45
60
75
toc04
5.5
DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
4.5
toc05
No load
4.0
VOD (V)
20
15
3.5
3.0
2.5
2.0
10
120Ω LOAD
54Ω LOAD
1.5
2.0
2.5
3.0
0.0
3.5
-45 -30 -15
0
DRIVER OUTPUT CURRENT
vs. OUTPUT HIGH VOLTAGE
toc07
30
25
-20
PROPAGATION DELAY (ns)
OUTPUT CURRENT (mA)
0
-40
-60
-80
-100
-140
15
30
45
60
-7 -6 -5 -4 -3 -2 -1
0
1
2
3
OUTPUT HIGH VOLTAGE (V)
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75
4
5
2.5
3.0
3.5
toc6
80
60
40
0
1
2
3
toc08
50
45
tPDHL
15
tPDLH
10
RL = 54Ω
CL = 50pF
-45 -30 -15
0
15
30
45
60
TEMPERATURE (°C)
4
5
6
7
8
9 10 11 12
OUTPUT LOW VOLTAGE (V)
20
0
2.0
100
0
90 105
TRANSMITTER PROPAGATION
DELAY vs. TEMPERATURE
5
-120
1.5
DRIVER OUTPUT CURRENT
vs. OUTPUT LOW VOLTAGE
TEMPERATURE (°C)
OUTPUT HIGH VOLTAGE (V)
20
1.0
20
PROPAGATION DELAY (ns)
1.5
0.5
120
0.5
1.0
0.0
140
1.0
5
0.5
10
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
25
0.0
15
0
90 105
5.0
0
20
TEMPERATURE (°C)
RECEIVER OUTPUT CURRENT
vs. OUTPUT HIGH VOLTAGE
toc03
5
NO LOAD
NO SWITCHING
TEMPERATURE (°C)
30
RECEIVER OUTPUT CURRENT
vs. OUTPUT LOW VOLTAGE
30
25
10
IDDB (mA)
IDDA (mA)
toc02
12
6
0
VDDB SUPPLY CURRENT
vs. TEMPERATURE
14
75
90 105
RECEIVER PROPAGATION
DELAY vs. TEMPERATURE
toc09
CL = 15pF
40
35
tRPLH
30
25
20
15
tRPHL
10
5
0
-45 -30 -15
0
15
30
45
60
75
90 105
TEMPERATURE (°C)
Maxim Integrated │ 10
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Typical Operating Characteristics (continued)
(VDDA - VGNDA = 3.3V, VDDB - VGNDB = 5V, VGNDA = VGNDB, and TA = +25°C, unless otherwise noted.)
DRIVER ENABLE/DISABLE
DELAY vs. TEMPERATURE
80
DRIVER
PROPAGATION DELAY
toc10
RL = 54Ω
CL = 50pF
ENABLE/DISABLE DELAY (ns)
70
50
tDHZ
tDZL
toc12
CL = 15pF
60
40
RECEIVER
PROPAGATION DELAY
toc11
TXD
2V/div
RXD
2V/div
0V
0V
A
1V/div
A
1V/div
B
1V/div
B
1V/div
30
20
10
0
tDLZ
-45 -30 -15
0
15
tDZH
30
45
60
75
10ns/div
90 105
10ns/div
TEMPERATURE (°C)
7
70
6
60
5
50
4
3
1
10
5
10
15
0
20
120Ω LOAD
NO LOAD
0
DATA RATE (Mbps)
TD1/TD2 VOLTAGE
vs. DRIVE CURRENT
400
600
54Ω LOAD
30
20
0
toc14
40
2
0
VDDB SUPPLY
CURRENT vs. DATA RATE
80
IDDB (mA)
IDDA (mA)
toc13
SWITCHING FREQUENCY (kHz)
VDDA SUPPLY CURRENT
vs. DATA RATE
8
5
10
15
DATA RATE (Mbps)
20
TRANSFORMER DRIVER SWITCHING
FREQUENCY vs. TEMPERATURE toc15
550
500
450
400
350
300
-45 -30 -15
15
30
45
60
75
90 105
TEMPERATURE (°C)
TRANSFORMER DRIVER
toc16
0
toc17
TD1/TD2 DRIVER VOLTAGE (mV)
350
300
VOUTN
250
VINSIDE
200
TD1 & TD2
2V/div
VBACKUP
150
0V
100
50
0
100mA LOAD ON VDDB
0
100
200
300
400
500
600
700
400ns/div
DRIVER CURRENT (mA)
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Maxim Integrated │ 11
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Pin Configuration
TOP VIEW
+
TD1
1
16 VDDB
TD2
2
GNDA
3
VDDA
4
13 B
RXD
5
12 A
RE
6
11 VLDO
DE
7
10 DEM
TXD
8
9
15 GNDB
MAX14943
14 GNDB
GNDB
WIDE SOIC
Pin Description
PIN
NAME
REFERENCE
1
TD1
GNDA
Transformer Driver Output 1
2
TD2
GNDA
Transformer Driver Output 2
3
GNDA
─
4
VDDA
GNDA
Logic-Side Power Input. Bypass VDDA to GNDA with both 0.1μF and 1µF capacitors as
close as possible to the device.
5
RXD
GNDA
Receiver Data Output. Drive RE low to enable RXD. With RE low, RXD is high when
(VA - VB) > -50mV and is low when (VA - VB) < -200mV. RXD is high when VDDB is less
than VUVLOB. RXD is high impedance when RE is high.
6
RE
GNDA
Receiver Output Enable. Drive RE low or connect to GNDA to enable RXD. Drive RE high
to disable RXD. RXD is high impedance when RE is high. RE has an internal 4.5µA
pulldown to GNDA.
www.maximintegrated.com
FUNCTION
UART/Logic-Side Ground. GNDA is the ground reference for digital signals and the
transformer driver.
Maxim Integrated │ 12
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Pin Description (continued)
PIN
NAME
REFERENCE
FUNCTION
7
DE
GNDA
Driver Output Enable. Drive DE high to enable bus-driver outputs A and B. Drive DE low or
connect to GNDA to disable A and B. A and B are high impedance when DE is low. DE has
an internal 4.5µA pulldown to GNDA.
8
TXD
GNDA
Driver Input. With DE high, a low on TXD forces the noninverting output (A) low and the
inverting output (B) high. Similarly, a high on TXD forces the noninverting output high and
the inverting output low. TXD has an internal 4.5µA pullup to VDDA.
9, 14, 15
GNDB
─
Cable-Side Ground. GNDB is the ground reference for the internal LDO, the DEM output,
and the RS-485/PROFIBUS bus signals.
10
DEM
GNDB
Driver Enable Monitor Output. DEM is high when the transmitter is enabled. See the
Function Table for more information.
VLDO
GNDB
LDO Power Input. Connect a minimum voltage of 4.68V to VLDO to power the cable side
of the transceiver. Bypass VLDO to GNDB with both 0.1μF and 1µF capacitors as close to
the device as possible. To disable the internal LDO, leave VLDO unconnected or connect
to GNDB.
12
A
GNDB
Noninverting Receiver Input and Noninverting Driver Output
13
B
GNDB
Inverting Receiver Input and Inverting Driver Output
GNDB
Cable-Side Power Input/Isolated LDO Power Output. Bypass VDDB to GNDB with both
a 0.1μF and 1μF capacitors as close as possible to the device. VDDB is the output of the
internal LDO when power is applied to VLDO. When the internal LDO is not used (VLDO is
unconnected or connected to GNDB), VDDB is the positive supply input for the cable side
of the IC.
11
16
VDDB
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Maxim Integrated │ 13
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Function Tables
TRANSMITTING
INPUTS
OUTPUTS
VDDA
VDDB
DE
TXD
A
B
DEM
≥ VUVLOA
≥ VUVLOB
1
1
1
0
1
≥ VUVLOA
≥ VUVLOB
1
0
0
1
1
≥ VUVLOA
≥ VUVLOB
0
X
High-Z
High-Z
0
< VUVLOA
≥ VUVLOB
X
X
High-Z
High-Z
0
≥ VUVLOA
< VUVLOB
X
X
High-Z
High-Z
0
< VUVLOA
< VUVLOB
X
X
High-Z
High-Z
0
*Drive DE low to disable the transmitter outputs. Drive DE high to enable the transmitter outputs. DE has an internal pulldown to
GNDA.
X = Don’t care.
RECEIVING
INPUTS
OUTPUTS
VDDA
VDDB
RE
(VA - VB)
RXD
≥ VUVLOA
≥ VUVLOB
0
> -50mV
1
≥ VUVLOA
≥ VUVLOB
0
< -200mV
0
≥ VUVLOA
≥ VUVLOB
0
Open/Short
1
≥ VUVLOA
≥ VUVLOB
1
X
High-Z
< VUVLOA
≥ VUVLOB
X
X
High-Z
≥ VUVLOA
< VUVLOB
0
X
1
< VUVLOA
< VUVLOB
X
X
High-Z
*Drive RE high to disable the receiver output. Drive RE low to enable to receiver output. RE has an internal pulldown to GNDA.
X = Don’t care.
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Maxim Integrated │ 14
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Detailed Description
The MAX14943 isolated RS-485/PROFIBUS DP transceiver
provides 5000VRMS (60s) of galvanic isolation between
the RS-485/PROFIBUS DP cable side of the transceiver
and the UART side. This device allows up to 20Mbps
communication across an isolation barrier when a large
potential exists between grounds on each side of the
barrier.
Isolation
Both data and power can be transmitted across the isolation
barrier. Data isolation is achieved using integrated capacitive
isolation that allows data transmission between the UART
side and the cable side of the transceiver.
To achieve power isolation, the device features an integrated
transformer driver to drive an external center-tapped transformer, allowing the transfer of operating power from the UART
side across the isolation barrier to the cable side. Connect
the primary side of the external transformer to the device’s
transformer driver outputs, TD1 and TD2. Connect the primary
center-tap to VDDA.
Integrated LDO
The device includes an internal low-dropout regulator with
a set 5V (typ) output that is used to power the cable side
of the IC. The output of the LDO is VDDB. The LDO has
a 300mA (typ) current limit. If the LDO is unused, connect
VLDO to GNDB and apply +5V directly to VDDB.
True Fail Safe
The device guarantees a logic-high on the receiver output
when the receiver inputs are shorted, open, or when connected
to a terminated transmission line with all drivers disabled.
The receiver threshold is fixed between -50mV and
-200mV. If the differential receiver input voltage (VA - VB)
is greater than or equal to -50mV, RXD is logic high. In
the case of a terminated bus with all transmitters disabled,
the receiver’s differential input voltage is pulled to zero by
the termination resistors. Due to the receiver thresholds
of the device, this results in a logic-high at RXD.
Driver Output Protection
Two mechanisms prevent excessive output current and
power dissipation caused by faults or by bus contention.
The first, a foldback-mode current limit on the output stage,
provides immediate protection against short circuits over
the entire common-mode voltage range. The second, a
thermal-shutdown circuit, forces the driver outputs into
a high-impedance state if the die temperature exceeds
+160°C (typ).
www.maximintegrated.com
Thermal Shutdown
The device is protected from overtemperature damage
by integrated thermal-shutdown circuitry. When the junction
temperature (TJ) exceeds +160°C (typ), the driver
outputs go high impedance. The device resumes normal
operation when TJ falls below +145°C (typ).
Transformer Driver
Overcurrent Limiting
The device features overcurrent limiting to protect the
integrated transformer driver from excessive currents
when charging large capacitive loads or driving into short
circuits. Current limiting is achieved in two stages: internal
circuitry monitors the output current and detects when the
peak current rises above 1.2A. When the 1.2A threshold
is exceeded, internal circuitry reduces the output current
to the 730mA current-limit. The device monitors the driver
current on a cycle-by-cycle basis and limits the current
until the short is removed.
The transformer driver on the device can dissipate large
amounts of power during overcurrent limiting, causing the
IC to enter thermal shutdown. When the junction temperature
of the driver exceeds the thermal-shutdown threshold,
the TD1 and TD2 driver outputs are disabled. The driver
resumes normal operation when the temperature falls
below the thermal-shutdown hysteresis.
Transformer Selection
The integrated push-pull transformer driver allows the
transmission of operating power from the UART side,
across the isolation barrier, to the isolated cable side of
the device. The 450kHz transformer driver operates with
center-tapped primary transformers. Select a transformer
with an ET product greater than or equal to the ET of the
driver to ensure that the transformer does not enter saturation. E is the voltage applied to the transformer and T is the
maximum time it is applied during any one cycle. Calculate
the minimum ET product for the transformer primary as:
ET = VMAX/(2 x fMIN)
Where VMAX is the worst-case maximum supply voltage
on VDDA and fMIN is the minimum frequency at that
supply voltage. For example, using 5.5V and 350kHz, the
required minimum ET product is 7.9Vµs. Table 1 includes
a list of recommended transformers.
Maxim Integrated │ 15
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Applications Information
Profibus Termination
128 Transceivers on the Bus
The standard RS-485 receiver input impedance is one unit
load, and a standard driver can drive up to 32 unit loads.
The device transceiver has a 1/4-unit load receiver, which
allows up to 128 transceivers connected in parallel on one
communication line. Connect any combination of these
devices, and/or other RS-485 devices, for a maximum of
32 unit loads to the line.
Typical Application
The MAX14943 transceiver is designed for bidirectional
data communications on multipoint bus-transmission lines.
Figure 10 and Figure 11 show typical network applications
circuits. To minimize reflections, the bus should be terminated at both ends in its characteristics impedance, and stub
lengths off the main line should be kept as short as possible.
The device is designed for driving PROFIBUS DP
terminated networks. The driver maintains 2.1V (min)
when driving a worst-case loading condition of two
standard 220Ω termination resistors with 390Ω pullups/
pulldowns.
Layout Considerations
It is recommended to design an isolation or keep out channel
underneath the isolator that is free from ground and signal
planes. Any galvanic or metallic connection between the
cable side and UART side defeats the isolation.
Ensure that the decoupling capacitors between VDDA and
GNDA and between VLDO, VDDB and GNDB are located
as close as possible to the IC to minimize inductance.
Route important signal lines close to the ground plane
to minimize possible external influences. On the cable
side of the device, it is good practice to have the bus
connectors and termination resistor as close as possible
to the A and B pins.
Table 1. Recommended Transformers
MANUFACTURER
PART NUMBER
APPLICATION
CONFIGURATION
ISOLATION
(VRMS)
DIMENSIONS
(L x W x H) (mm)
HALO TGMR-1440V6LF
5V to 5V
1CT:1.33CT
5000
9.45 x 10.87 x 10.03
HALO TGMR-1464V6LF
3.3V to 5V
1CT:2.4CT
5000
9.45 x 10.87 x 10.03
WURTH 750315229
5V to 5V
1CT:1.1CT
5000
9.14 x 8.00 x 7.62
WURTH 750315230
5V to 5V
1CT:1.3CT
5000
9.14 x 8.00 x 7.62
WURTH 750315231
3.3V to 5V
1CT:1.7CT
5000
9.14 x 8.00 x 7.62
WURTH 750315232
3.3V to 5V
1CT:2CT
5000
9.14 x 8.00 x 7.62
www.maximintegrated.com
Maxim Integrated │ 16
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
RXD
RE
TXD
DE
A
RS-485 TRANSCEIVER
RS-485 TRANSCEIVER
MAX14943
A
120Ω
120Ω
B
B
B
A
B
RS-485 TRANSCEIVER
RXD
RE
TXD
DE
A
RS-485 TRANSCEIVER
MAX14943
INTEGRATED
ISOLATION BARRIER
DE
TXD RE
RXD
DE
TXD RE
RXD
Figure 10. Typical Isolated Half-Duplex RS-485 Application
VDDA
10µF
1µF
TD1
1µF
1
1
TD2
VDDA
1
2
RE
2
TXD
DE
A
3
VDDB
0.1µF
0.1µF
2
390Ω
390Ω
PROFIBUS A LINE
2
220Ω
B
3
1µF
3
A
220Ω
B
PROFIBUS B LINE
390Ω
390Ω
2
1
4
3
VLDO
MAX14943
TD2
TD1
VDDA
1µF
4
0.1µF
4
RXD
RS-485 Transceiver
RXD
10µF
3
1µF 0.1µF
0.1µF
VLDO
VDDB
MAX14943
1µF
RS-485 Transceiver
0.1µF
3
2
2
VDDA
10µF
10µF
RE
TXD
DE
3
2
3
4
Figure 11. Typical Isolated PROFIBUS Application with Integrated Transformer Driver
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Maxim Integrated │ 17
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Extended ESD Protection
ESD-protection structures are incorporated on all pins
to protect against electrostatic discharge encountered
during handling and assembly. The driver outputs and
receiver inputs of the MAX14943 have extra protection
against static electricity. The ESD structures withstand
high ESD in normal operation and when powered down.
After an ESD event, the devices keep working without
latchup or damage.
Bypass VDDA to GNDA and bypass VDDB and VLDO to
GNDB with 0.1μF and 1μF capacitors to ensure maximum
ESD protection.
ESD protection can be tested in various ways. The
transmitter outputs and receiver inputs of the MAX14943
are characterized for protection to the cable-side ground
(GNDB) to the following limits:
●●
±35kV HBM
●●
±12kV using the Air-Gap Discharge method specified
in IEC 61000-4-2
●●
±10kV using the Contact Discharge method specified
in the IEC 61000-4-2
ESD Test Conditions
Human Body Model (HBM)
Figure 12 shows the HBM test model and Figure 13 shows
the current waveform it generates when discharged in
a low-impedance state. 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.
IEC 61000-4-2
The IEC 61000-4-2 standard covers ESD testing and
performance of finished equipment. However, it does not
specifically refer to integrated circuits. The MAX14943 helps
in designing equipment to meet IEC 61000-4-2 without the
need for additional ESD-protection components.
The major difference between tests done using the HBM
and IEC 61000-4-2 is higher peak current in IEC 61000-4-2
because series resistance is lower in the IEC 61000-4-2
model. Hence, the ESD withstand voltage measured to
IEC 61000-4-2 is generally lower than that measured using
the HBM.
Figure 14 shows the IEC 61000-4-2 model and Figure 15
shows the current waveform for the IEC 61000-4-2 ESD
Contact Discharge Test.
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents test
setup, test methodology, and test results.
RC
1MΩ
CHARGE-CURRENTLIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
100pF
RD
1500Ω
IP 100%
90%
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Ir
AMPS
DEVICE
UNDER
TEST
36.8%
10%
0
0
Figure 12. Human Body ESD Test Model
www.maximintegrated.com
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
tRL
TIME
tDL
CURRENT WAVEFORM
Figure 13. Human Body Current Waveform
Maxim Integrated │ 18
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
CHARGE-CURRENTLIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
150pF
RD
330Ω
I
100%
90%
DISCHARGE
RESISTANCE
IPEAK
RC
50MΩ TO 100MΩ
DEVICE
UNDER
TEST
STORAGE
CAPACITOR
10%
tr = 0.7ns TO 1ns
t
30ns
60ns
Figure 14. IEC 61000-4-2 ESD Test Model
Figure 15. IEC 61000-4-2 ESD Generator Current Waveform
Typical Application Circuit
V DDA
TD1
V LDO
TD2
LDO
V DDA
DRIVER
V DDB
450kHz
OSC
µC
RS-485
TRANSCEIVER
RXD
RE
TXD
DE
GNDA
MAX14943
A
B
DEM
GNDB
ISOLATION
BARRIER
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Maxim Integrated │ 19
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Ordering Information
PART
Package Information
TEMP RANGE
PIN-PACKAGE
MAX14943GWE+
-40°C to +105°C
16 SOIC (W)
MAX14943GWE+T
-40°C to +105°C
16 SOIC (W)
+Denotes a lead(Pb)-free/RoHS-compliant package.
Chip Information
PROCESS: BiCMOS
www.maximintegrated.com
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.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
OUTLINE
NO.
LAND PATTERN
NO.
16 SOIC
W16M+10
21-0042
90-0107
Maxim Integrated │ 20
MAX14943
5kVRMS Isolated 20Mbps Half-Duplex PROFIBUS DP/
RS-485 Transceiver with ±35kV ESD Protection and
Integrated Transformer Driver
Revision History
REVISION
NUMBER
REVISION
DATE
0
6/15
DESCRIPTION
Initial release
PAGES
CHANGED
—
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2015 Maxim Integrated Products, Inc. │ 21