MAX14856,58 Datasheet by Maxim Integrated

View All Related Products | Download PDF Datasheet
maxim integrated ,,
General Description
The MAX14856/MAX14858 isolated RS-485/RS-422
transceivers provide 5000VRMS (60s) of galvanic
isolation between the cable side (RS-485/RS-422 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. These devices allow for robust
communication up to 500kbps (MAX14856) or 25Mbps
(MAX14858).
The devices include one drive channel and one receive
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 the cable side or UART side
power supplies are below functional levels.
The driver outputs and receiver inputs are protected
from ±35kV electrostatic discharge (ESD) to GNDB on
the cable side, as specified by the Human Body Model
(HBM).
The devices are available in a wide-body 16-pin
SOIC package and operate over the -40°C to +105°C
temperature range.
Benefits and Features
High-Performance Transceiver Enables Flexible Designs
Integrated LDO for Cable Side Power
Compliant with RS-485 EIA/TIA-485 Standard
500kbps (MAX14856)/25Mbps (MAX14858)
Maximum Data Rate
Allows Up to 128 Devices on the Bus
Integrated Protection Ensures for Robust
Communication
±35kV ESD (HBM) on Driver Outputs/Receiver Inputs
5kVRMS Withstand Isolation Voltage for 60
Seconds (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
Safety Regulatory Approvals
UL According to UL1577
cUL According to CSA Bulletin 5A
Applications
Industrial Automation Equipment
Programmable Logic Controllers
HVAC
Power Meters
Ordering Information appears at end of data sheet.
19-7966; Rev 1; 1/17
Functional Diagram
LDO
RS-485
TRANSCEIVER
VDDA
RXD
RE
TXD
DE
A
B
VDDB
VLDO
GNDA GNDB
MAX14856
MAX14858
SBA
Z
Y
MAX14856/MAX14858 5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
EVALUATION KIT AVAILABLE
VDDA to GNDA ......................................................-0.3V to +6V
VDDB to GNDB .......................................................-0.3V to +6V
VLDO to GNDB .....................................................-0.3V to +16V
TXD, DE, RE to GNDA ...........................................-0.3V to +6V
SBA, RXD to GNDA ............................. -0.3V to (VDDA + 0.3V)
A, B, Z, Y to GNDB ..................................................-8V to +13V
Short Circuit Duration (RXD, SBA to GNDA,
A, B, Y, Z ,VDDB to GNDB) ...................................Continuous
Continuous Power Dissipation (TA = +70°C)
16-pin Wide 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
Junction-to-Ambient Thermal Resistance JA) ..............71°C/W Junction-to-Case Thermal Resistance (θJC) ...................23°C/W
(Note 1)
DC Electrical Characteristics
(VDDA – VGNDA = 1.71V to 5.5V, VDDB – VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are
at VDDA – VGNDA = 3.3V, VDDB – VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER
Supply Voltage VDDA 1.71 5.5 V
VDDB 3.0 5.5
Supply Current
IDDA
VDDA = 5V, DE = high, RE = TXD = low,
RXD unconnected, no load 3.9 6.6
mA
IDDB
DE = high, RE = TXD = low, RXD
unconnected, no bus load, VDDB = 3.3V 7 12.5
Undervoltage-Lockout
Threshold
VUVLOA VDDA rising 1.50 1.58 1.65 V
VUVLOB VDDB rising 2.55 2.7 2.85
Undervoltage-Lockout
Threshold Hysteresis
VUVHYSTA 50 mV
VUVHYSTB 200
LDO
LDO Supply Voltage VLDO Relative to GNDB, LDO is on (Note 4) 3.18 14 V
LDO Supply Current ILDO DE = high, TXD = low, no bus load,
VLDO = 5.5V 7.5 12.9 mA
LDO Output Voltage VDDB 3.0 3.3 3.6 V
LDO Current Limit 300 mA
Load Regulation VLDO = 3.3V, ILOAD = 20mA to 40mA 0.19 1.7 mV/mA
Line Regulation VLDO = 3.3V to 14V, ILOAD = 20mA 0.12 1.8 mV/V
Dropout Voltage VLDO = 3.18V, IDDB = -120mA 100 180 mV
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
2
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
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.
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.
Package Thermal Characteristics
DC Electrical Characteristics (continued)
(VDDA – VGNDA = 1.71V to 5.5V, VDDB – VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are
at VDDA – VGNDA = 3.3V, VDDB – VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Load Capacitance Nominal value (Note 7) 1 10 µF
LOGIC INTERFACE (TXD, RXD, DE, RE, SBA)
Input High Voltage VIH
RE, TXD, DE to
GNDA
2.25V VDDA
5.5V
0.7 x
VDDA V
1.71V VDDA
1.89V
0.78 x
VDDA
Input Low Voltage VIL
RE, TXD, DE to
GNDA
2.25V VDDA
5.5V 0.8
V
1.71V VDDA
1.89V 0.6
Input Hysteresis 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
SBA Pullup Resistance RSBA 3 5 8 kΩ
Output Voltage High VOH RXD to GNDA, IOUT = -4mA VDDA
-0.4 V
Output Voltage Low VOL
RXD to GNDA, IOUT = 4mA 0.40
V
SBA to GNDA, IOUT = 4mA 0.45
Short-Circuit Output Pullup
Current ISH_PU 0V ≤ VRXD ≤ VDDA, (VA - VB) > -10mV,
RE = low -42 mA
Short-Circuit Output Pulldown
Current ISH_PD
0V ≤ VRXD ≤ VDDA, (VA - VB) <
-200mV, RE = low 40
mA
0V ≤ VSBA ≤ VDDA, side B is powered
and working 60
Three-State Output Current IOZ 0V ≤ VRXD ≤ VDDA, RE = high -1 +1 µA
DRIVER
Differential Driver Output |VOD|
RL = 54Ω, TXD = high or low, Figure 1a 1.5
V
RL = 100Ω, TXD = high or low, Figure 1a 2.0
-7V VCM +12V, Figure 1b 1.5 5
Change in Magnitude of Differential
Driver Output Voltage ΔVOD RL = 100Ω or 54Ω, Figure 1a (Note 5) 0.2 V
Driver Common Mode Output
Voltage VOC RL = 100Ω or 54Ω, Figure 1a (Note 5) VDDB/
23 V
Change in Magnitude of
Common-Mode Voltage ΔVOC RL = 100Ω or 54Ω, Figure 1a (Note 5) 0.2 V
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
3
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
DC Electrical Characteristics (continued)
(VDDA – VGNDA = 1.71V to 5.5V, VDDB – VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are
at VDDA – VGNDA = 3.3V, VDDB – VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Driver Short-Circuit Output
Current IOSD
GNDB ≤ VOUT ≤ +12V, output low (Note
6) +30 +250
mA
-7V ≤ VOUT ≤ VDDB, output high (Note 6) -250 -30
Single-Ended Driver Output
Voltage High VOH Y and Z outputs, IY, Z = -20mA 2.2 V
Single-Ended Driver Output
Voltage Low VOL Y and Z outputs, IY, Z = +20mA 0.8 V
Differential Driver Output
Capacitance COD DE = RE = high, f = 4MHz 12 pF
RECEIVER
Input Current (A and B) IA, IBDE = low, VDDB
= GNDB or 3.6V
VIN = +12V +250 µA
VIN = -7V -200
Receiver Differential Threshold
Voltage VTH -7V ≤ VCM ≤ +12V -200 -120 -10 mV
Receiver Input Hysteresis ΔVTH VCM = 0V 20 mV
Receiver Input Resistance RIN -7V ≤ VCM ≤ +12V, DE = low 48
Differential Input Capacitance CA,B Measured between A and B, DE = RE =
low at 6MHz 12 pF
PROTECTION
Thermal-Shutdown Threshold TSHDN Temperature Rising +160 °C
Thermal-Shutdown Hysteresis THYST 15 °C
ESD Protection
(A and B Pins to GNDB)
Human Body Model ±35
kV
IEC 61000-4-2 Air Gap Discharge ±18
IEC 61000-4-2 Contact Discharge ±8
ESD Protection (All Other Pins) Human Body Model ±4 kV
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
4
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Switching Electrical Characteristics (MAX14856)
(VDDA – VGNDA = 1.71V to 5.5V, VDDB – VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are
at VDDA – VGNDA = 3.3V, VDDB – VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DYNAMIC
Common Mode Transient
Immunity CMTI (Note 8) 35 kV/μs
Glitch Rejection TXD, DE, RXD 10 17 29 ns
DRIVER
Driver Propagation Delay tDPLH, tDPHL RL = 54Ω, CL = 50pF, Figure 2 and
Figure 3 1040 ns
Differential Driver Output Skew
|tDPLH - tDPHL|tDSKEW RL = 54Ω, CL = 50pF, Figure 2 and
Figure 3 144 ns
Driver Differential Output Rise
or Fall Time tLH, tHL RL = 54Ω, CL = 50pF, Figure 2 and
Figure 3 900 ns
Maximum Data Rate DRMAX 500 kbps
Driver Enable to Output High tDZH RL = 110Ω, CL = 50pF, Figure 5 2540 ns
Driver Enable to Output Low tDZL RL = 110Ω, CL = 50pF, Figure 5 2540 ns
Driver Disable Time from Low tDLZ RL = 110Ω, CL = 50pF, Figure 5 140 ns
Driver Disable Time from High tDHZ RL = 110Ω, CL = 50pF, Figure 4 140 ns
RECEIVER
Receiver Propagation Delay tRPLH, tRPHL CL = 15pF, Figure 6 and Figure 7
(Note 9) 240 ns
Receiver Output Skew
|tRPLH - tRPHL|tRSKEW CL = 15pF, Figure 6 and Figure 7
(Note 9) 34 ns
Maximum Data Rate DRMAX 500 kbps
Receiver Enable to Output
High tRZH RL = 1kΩ, CL = 15pF, S2 closed,
Figure 8 20 ns
Receiver Enable to Output Low tRZL RL = 1kΩ, CL = 15pF, S1 closed,
Figure 8 30 ns
Receiver Disable Time From
Low tRLZ RL = 1kΩ, CL = 15pF, S1 closed,
Figure 8 20 ns
Receiver Disable Time From
High tRHZ RL = 1kΩ, CL = 15pF, S2 closed,
Figure 8 20 ns
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
5
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
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: ΔVOD and ΔVOC are the changes in VOD and VOC, respectively, when the TXD input changes state.
Note 6: The short circuit output current applies to the peak current just prior to current limiting.
Note 7: Not production tested. Guaranteed by design.
Note 8: 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. VCM = 1kV
Note 9: Capacitive load includes test probe and fixture capacitance.
Switching Electrical Characteristics (MAX14858)
(VDDA – VGNDA = 1.71V to 5.5V, VDDB – VGNDB = 3.0V to 5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are
at VDDA – VGNDA = 3.3V, VDDB – VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25°C.) (Notes 2, 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DYNAMIC
Common Mode Transient
Immunity CMTI (Note 8) 35 kV/μs
Glitch Rejection TXD, DE, RXD 10 17 29 ns
DRIVER
Driver Propagation Delay tDPLH, tDPHL RL = 54Ω, CL = 50pF, Figure 2 and
Figure 3 65 ns
Differential Driver Output Skew
|tDPLH - tDPHL|tDSKEW RL = 54Ω, CL = 50pF, Figure 2 and
Figure 3 7 ns
Driver Differential Output Rise
or Fall Time tLH, tHL RL = 54Ω, CL = 50pF, Figure 2 and
Figure 3 10 ns
Maximum Data Rate DRMAX 25 Mbps
Driver Enable to Output High tDZH RL = 110Ω, CL = 50pF, Figure 4 80 ns
Driver Enable to Output Low tDZL RL = 110Ω, CL = 50pF, Figure 5 80 ns
Driver Disable Time from Low tDLZ RL = 110Ω, CL = 50pF, Figure 5 80 ns
Driver Disable Time from High tDHZ RL = 110Ω, CL = 50pF, Figure 4 80 ns
RECEIVER
Receiver Propagation Delay tRPLH, tRPHL CL = 15pF, Figure 6 and Figure 7
(Note 9) 65 ns
Receiver Output Skew
|tRPLH - tRPHL|tRSKEW CL = 15pF, Figure 6 and Figure 7
(Note 9) 7 ns
Maximum Data Rate DRMAX 25 Mbps
Receiver Enable to Output High tRZH RL = 1kΩ, CL = 15pF, S2 closed,
Figure 8 20 ns
Receiver Enable to Output Low tRZL RL = 1kΩ, CL = 15pF, S1 closed,
Figure 8 30 ns
Receiver Disable Time From Low tRLZ RL = 1kΩ, CL = 15pF, S1 closed,
Figure 8 20 ns
Receiver Disable Time From High tRHZ RL = 1kΩ, CL = 15pF, S2 closed,
Figure 8 20 ns
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
6
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Safety Regulatory Approvals
Insulation Characteristics
Note 10: VIORM, VIOWM, and VISO are defined by the IEC 60747-5-5 standard.
Note 11: Product is qualified at VISO for 60 seconds. 100% production tested at 120% of VISO for 1 second.
UL
The MAX14856/MAX14858 is certified under UL1577. For more details, see File E351759.
Rate up to 5000VRMS isolation voltage for basic insulation.
cUL
The MAX14856/MAX14858 is certified under UL1577. For more details, see File E351759. Rate up to 5000VRMS isolation voltage
for basic insulation.
PARAMETER SYMBOL CONDITIONS VALUE UNITS
Partial Discharge Test Voltage VPR
Method B1 = VIORM x 1.875 (t = 1s, par-
tial discharge < 5pC) 2250 VP
Maximum Repetitive Peak Withstand
Voltage VIORM (Note 7) 1200 VP
Maximum Working Isolation Voltage VIOWM (Note 7) 848 VRMS
Maximum Transient Isolation Voltage VIOTM t = 1s 8400 VP
Maximum Withstand Isolation Voltage VISO t = 60s, f = 60Hz (Note 7, 8) 5000 VRMS
Maximum surge Isolation Voltage VIOSM IEC 61000-4-5, 1.2/50μs 10 kV
Insulation Resistance RSTA = +150°C, VIO = 500V >109Ω
Barrier Capacitance Input to Output CIO 2 pF
Creepage Distance CPG Wide SO 8 mm
Clearance Distance CLR Wide SO 8 mm
Internal Clearance Distance through insulation 0.015 mm
Comparitive Tracking Resistance
Index CTI Material Group II (IEC 60112) 575
Climatic Category 40/125/21
Pollution Degree (DIN VDE 0110, Table 1) 2
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
7
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Ii
Figure 1. Driver DC Test Load
R
L
2
R
L
2
V
OC
V
OD
Y
Z
(a)
375
V
CM
Y
Z
(b)
375
+
-
60
V
OD
RLCL
VOD
TXD
GNDA
Y
Z
50% 50%
GNDA
TXD
Z
Y
20%
80%
20%
80%
0
VO
-VO
VDIFF
tDSKEW = |tDPLH - tDPHL|
VDIFF = VY - VZ
VDDA
tLH P 3ns, tHL P 3ns
1/2 VO
tDPLH
tLH tHL
tDPHL
VO
1/2 VO
Figure 2. Driver Timing Test Circuit
Figure 3. Driver Propagation Delays
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
8
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
\‘H
Figure 4. Driver Enable and Disable Times (tDHZ, tDZH)
Figure 5. Driver Enable and Disable Times (tDZL, tDLZ)
GNDA
GNDB
250mV
50%
tDZH
tDHZ
DE
VDDA
VOH
50%
OUT
RL = 500I
50I
OUT
S1
Y
Z
D
TXD
GNDA OR VDDA
GNDA
GNDB
GENERATOR
DE
CL
50pF
RL = 500I
CL = 50pF
50I
GNDB
GNDA
OUT
GNDA
250mV
50%
tDZL
tDLZ
DE
S1
Y
Z
D
TXD
GNDA OR VDDA
VDDB
VDDA
50%
OUT
VDDB
VOL
GENERATOR
DE
Figure 6. Receiver Propagation Delay Test Circuit
VID
B
A
RECEIVER
OUTPUT
ATE R
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
9
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Figure 7. Receiver Propagation Delays
A
B
VOH
VOL
RXD
tRPHL
tRSKEW = |tRPHL - tRPLH|
tLH P 3ns, tHL P 3ns
tRPLH
-1V
1V
2
VDDA
2
VDDA
Figure 8. Receiver Enable and Disable Times
GENERATOR 50I
RL
1kI
CL
15pF
R
-1.5V
+1.5V
RXD
S1 VDDA
GNDA
GNDB
GNDA
S2
S3
VID
RE
RE
RXD
RE
RXD
RE RE
RXD RXD
GNDA
tRHZ tRLZ
0.25V
0.25V
50% 50%
GNDA GNDA
2
S1 OPEN
S2 CLOSED
S3 = +1.5V
S1 OPEN
S2 CLOSED
S3 = +1.5V
S1 CLOSED
S2 OPEN
S3 = -1.5V
S1 CLOSED
S2 OPEN
S3 = -1.5V
VOH
GNDA
GNDA
VOH
VDDA
VDDA
VDDA
50%50%
VDDA
tRZL
VOL
GNDA
VDDA
VDDA
VDDA
VOL
tRZH
2
VDDA
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
10
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
vm sumvcunkw vs. mvawunz MAxmsc wwsumn PROPAGMIOM new v1.1EMPBiA'NRE v”. sumv CURREN'I FERBmAL wmvomai v1. TBAPERAIURE vs. rEMPaumRE MAXIM RECEIVER PNOPAGAYM qumsc DRIVER EMBLEDWLE DELAY u. rEMPBwuns DELAvvx. TWPERATURE mum nan/a? PROPAGATION uaAv mum, qumsc RECEIVER Mums: musmmai PROPAGAIION PROPAGA'IDN new DELAY". TEMPEWURE Ii
(VDDA – VGNDA = 3.3V, VDDB – VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25°C, unless otherwise noted.)
0
100
200
300
400
500
600
700
800
900
1000
-45 -30 -15 015 30 45 60 75 90 105
PROPAGATION DELAY (ns)
TEMPERATURE (°C)
MAX14856 TRANSMITTER PROPAGATION
DELAY vs. TEMPERATURE toc04
RL= 54
CL= 50pF
tPDHL
tPDLH
0
1
2
3
4
5
6
7
8
-45 -30 -15 015 30 45 60 75 90 105
IDDA (mA)
TEMPERATURE (°C)
VDDA SUPPLY CURRENT
vs. TEMPERATURE toc01
NO LOAD
NO SWITCHING
MAX14856 DRIVER
PROPAGATION DELAY
TXD
2V/div
0V
Y
1V/div
Z
1V/div
toc07
100ns/div
VOUTN
VINSIDE
VBACKUP
RL= 54
CL= 50pF
0
2
4
6
8
10
12
14
-45 -30 -15 015 30 45 60 75 90 105
IDDB (mA)
TEMPERATURE (°C)
VDDB SUPPLY CURRENT
vs. TEMPERATURE toc02
NO LOAD
NO SWITCHING
MAX14856 RECEIVER
PROPAGATION DELAY
RXD
2V/div
0V
B
1V/div
A
1V/div
toc08
100ns/div
CL= 15pF
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
-45 -30 -15 015 30 45 60 75 90 105
VOD (V)
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE toc03
No load
120LOAD
54LOAD
0
5
10
15
20
25
30
35
40
45
50
55
60
65
-45 -30 -15 015 30 45 60 75 90 105
PROPAGATION DELAY (ns)
TEMPERATURE (°C)
MAX14858 TRANSMITTER PROPAGATION
DELAY vs. TEMPERATURE toc09
RL= 54
CL= 50pF
tPDHL
tPDLH
0
20
40
60
80
100
120
140
160
180
200
220
240
-45 -30 -15 015 30 45 60 75 90 105
PROPAGATION DELAY (ns)
TEMPERATURE (°C)
MAX14856 RECEIVER PROPAGATION
DELAY vs. TEMPERATURE toc05
tRPHL
tRPLH
CL= 15pF
0
100
200
300
400
500
600
700
800
900
1000
-45 -30 -15 015 30 45 60 75 90 105
ENABLE/DISABLE DELAY (ns)
TEMPERATURE (°C)
MAX14856 DRIVER ENABLE/DISABLE
DELAY vs. TEMPERATURE toc06
tDZH
tDZL
tDHZ
tDLZ
Maxim Integrated
11
www.maximintegrated.com
MAX14856/MAX14858 5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Typical Operating Characteristics
mxmsu RECEIVE: “mama" mime DRIVER mats/DISABLE MAXMSH DRIVER DEMVVI. TBAFEM'URE new". TEMPERANRE PROPABAWN DEN MAXMSH RECEIVER RECEIVE? ENABLHDISABLE Van SUFFLVOURRWY momentum DELAY DEWuJEMPsVANRE mum RATE a vm. snmv wnnaum. mm an: OA
(VDDA – VGNDA = 3.3V, VDDB – VGNDB = 3.3V, VGNDA = VGNDB, and TA = +25°C, unless otherwise noted.)
MAX14858 DRIVER
PROPAGATION DELAY
TXD
2V/div
0V
Y
1V/div
Z
1V/div
toc12
10ns/div
VOUTN
VINSIDE
VBACKUP
RL= 54
CL= 50pF
0
5
10
15
20
25
30
35
40
45
50
55
60
65
-45 -30 -15 015 30 45 60 75 90 105
PROPAGATION DELAY (ns)
TEMPERATURE (°C)
MAX14858 RECEIVER PROPAGATION
DELAY vs. TEMPERATURE toc10
tRPHL
tRPLH
CL= 15pF
0
2
4
6
8
10
12
14
16
18
20
-45 -30 -15 015 30 45 60 75 90 105
ENABLE/DISABLE DELAY (ns)
TEMPERATURE (°C)
RECEIVER ENABLE/DISABLE
DELAY vs. TEMPERATURE toc14
tRZH
tRZL
tRHZ
tRLZ
0
10
20
30
40
50
60
70
80
-45 -30 -15 015 30 45 60 75 90 105
ENABLE/DISABLE DELAY (ns)
TEMPERATURE (°C)
MAX14858 DRIVER ENABLE/DISABLE
DELAY vs. TEMPERATURE toc11
tDZH
tDZL
tDHZ
tDLZ
0
1
2
3
4
5
6
7
8
0 5 10 15 20 25
IDDA (mA)
DATA RATE (Mbps)
VDDA SUPPLY CURRENT
vs. DATA RATE toc15
MAX14858 RECEIVER
PROPAGATION DELAY
A
1V/div
B
1V/div
RXD
2V/div
toc13
10ns/div
VOUTN
VINSIDE
VBACKUP
0V
CL= 15pF
0
10
20
30
40
50
60
70
0 5 10 15 20 25
IDDB (mA)
DATA RATE (Mbps)
VDDB SUPPLY
CURRENT vs. DATA RATE toc16
NO LOAD
54LOAD
120LOAD
Maxim Integrated
12
www.maximintegrated.com
MAX14856/MAX14858 5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Typical Operating Characteristics (continued)
jjjjjjjj R SBA
PIN NAME REFERENCE FUNCTION
1 VDDA GNDA UART/Logic-Side Power Input. Bypass VDDA to GNDA with both 0.1µF and 1µF
capacitors as close to the device as possible.
2, 8 GNDA - UART/Logic-Side Ground. GNDA is the ground reference for digital signals.
3 RXD GNDA
Receiver Data Output. Drive RE low to enable RXD. With RE low, RXD is high when (VA
VB) > -10mV and is low when (VA – VB) < -200mV. RXD is high when VDDB is less than
VUVLOB. RXD is high impedance when RE is high.
4RE GNDA
Receiver Output Enable. Driver 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 pull-
down to GNDA.
5 DE GNDA
Driver Output Enable. Drive DE high to enable bus driver outputs Y and Z. Drive DE low or
connect to GNDA to disable Y and Z. Y and Z are high impedance when DE is low. DE has
an internal 4.5µA pull-down to GNDA.
6 TXD GNDA
Driver Input. With DE high, a low on TXD forces the noninverting output (Y) low and the
inverting output (Z) 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.
7SBA GNDA Side B Active Indicator Output. SBA asserts low when side B is powered and working. SBA
has an internal 5kΩ pull-up resistor to VDDA.
WIDE SOIC
A
BRE
1
2
16
15
V
DDB
GNDBGNDA
RXD
V
DDA
TOP VIEW
3
4
14
13
Y
V
LDO
SBA
5 12 ZDE
TXD 6
7
11
10
GNDBGNDA 8 9
MAX14856
MAX14858
+
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
13
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Pin Configuration
Pin Description
PIN NAME REFERENCE FUNCTION
9, 15 GNDB - Cable Side Ground. GNDB is the ground reference for the internal LDO and the RS-485/
RS-422 bus signals.
10 VLDO GNDB
LDO Power Input. Connect a minimum voltage of 3.18V 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.
11 Y GNDB Noninverting Driver Output
12 Z GNDB Inverting Driver Output
13 B GNDB Inverting Receiver Input
14 A GNDB Noninverting Receiver Input
16 VDDB GNDB
Cable Side Power Input/Isolated LDO Power Output. Bypass VDDB to GNDB with both
0.1µF and 1μF capacitor as close to the device as possible. 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.
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
14
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Pin Description (continued)
*Note: 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
*Note: 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
Function Tables
TRANSMITTING
INPUTS OUTPUTS
VDDA VDDB DE TXD Y Z
≥ VUVLOA ≥ VUVLOB 1110
≥ VUVLOA ≥ VUVLOB 1001
≥ VUVLOA ≥ VUVLOB 0 X High-Z High-Z
< VUVLOA ≥ VUVLOB X X High-Z High-Z
≥ VUVLOA < VUVLOB X X High-Z High-Z
< VUVLOA < VUVLOB X X High-Z High-Z
RECEIVING
INPUTS OUTPUTS
VDDA VDDB RE (VA- VB) RXD
≥ VUVLOA ≥ VUVLOB 0 > -10mV 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
SBA
VDDA VDDB SBA
< VUVLOA < VUVLOB High
< VUVLOA ≥ VUVLOB High
≥ VUVLOA < VUVLOB High
≥ VUVLOA ≥ VUVLOB Low
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
15
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Detailed Description
The MAX14856/MAX14858 isolated RS-485/RS-422
transceivers provide 5000VRMS (60s) of galvanic
isolation between the RS-485/RS-422 cable side of the
transceiver and the UART side. These devices allow up to
500kbps (MAX14856)/25Mbps (MAX14858) communication
across an isolation barrier when a large potential exists
between grounds on each side of the barrier.
Isolation
Data isolation is achieved using high-voltage capacitors
that allow data transmission between the UART side and
the RS-485/RS-422 cable side of the transceiver.
Integrated LDO
The devices include an internal low-dropout regulator with
a set 3.3V (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 +3.3V directly to VDDB.
True Fail-Safe
The devices guarantee a logic-high on the receiver output
when the receiver inputs are shorted or open, or when
connected to a terminated transmission line with all drivers
disabled. The receiver threshold is fixed between -10mV
and -200mV. If the differential receiver input voltage (VA
– VB) is greater than or equal to -10mV, 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 devices, this results in a logic-high at
RXD.
Driver Output Protection
Two mechanisms prevent excessive output current and
power dissipation caused by faults or bus contention.
The first, a 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).
Thermal Shutdown
The devices are 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).
Applications Information
128 Transceivers on the Bus
The standard RS-485 receiver input impedance is one
unit load. A standard driver can drive up to 32 unit-loads.
The devices’ transceivers have 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 MAX14856/MAX14858 full-duplex transceivers are
designed for bidirectional data communications on multi-
point bus transmission lines. Figure 9 and Figure 10 show
typical network application 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.
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
16
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Figure 9. Typical Isolated Full-Duplex RS-485/RS-422 Application
RXD
RE
TXD
DE
RS-485 TRANSCEIVER
Y
Z
RXD
RE
TXD
DE
RS-485 TRANSCEIVER
A
B
RXDRETXDDE
RS-485 TRANSCEIVER
AB
RXDRETXDDE
RS-485 TRANSCEIVER
AB
120
INTEGRATED
ISOLATION
BARRIER
MAX14856
MAX14858
Master Slave
Slave
Slave
Figure 10. Typical Isolated Point-to-Point Application
RXD
RE
TXD
DE
RS-485 TRANSCEIVER
Y
Z
MAX14856
MAX14858
V
LDO
V
DDB
V
DDA
1
1
2
2
1uF 1uF
2
1uF
LDO
1
0.1uF
2
0.1uF
1uF
RXD
RE
TXD
DE
RS-485 TRANSCEIVER
A
B
V
DDB
V
DDA
3
34
4
1uF
V
LDO
1uF
3
MAX14856
MAX14858
3
0.1uF
0.1uF
4
LDO
2
0.1uF
3
0.1uF
120
120
A
B
Y
Z
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
17
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
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 will defeat 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 devices, it is good practice to have the bus connectors
and termination resistor as close as possible to the A and
B pins.
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 MAX14856/MAX14858 have extra
protection against static electricity to both the UART side
and cable side ground references. The ESD structures
withstand high-ESD events during normal operation and
when powered down. After an ESD event, the devices
keep working without latch-up 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 MAX14856/
MAX14858 are characterized for protection to the cable
side ground (GNDB) to the following limits:
±35kV HBM
±18kV using the Air-Gap Discharge method specified
in IEC 61000-4-2
±8kV using the Contact Discharge method specified
in IEC 61000-4-2
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents test
setup, test methodology, and test results.
Human Body Model (HBM)
Figure 11 shows the HBM test model, while Figure 12
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 MAX14856/
MAX14858 help 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 13 shows the IEC 61000-4-2 model and
Figure 14 shows the current waveform for IEC 61000-4-2
ESD Contact Discharge Test.
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
18
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
» o/x AAA [AAA c/ g "\* ************************* 4» +< suns="">
Figure 11. Human Body ESD Test Model Figure 12. Human Body Current Waveform
CHARGE-CURRENT-
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
100pF
RC
1M
RD
1500
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
IP 100%
90%
36.8%
tRL TIME
tDL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Ir
10%
0
0
AMPS
Figure 13. IEC 61000-4-2 ESD Test Model Figure 14. IEC 61000-4-2 ESD Generator Current Waveform
CHARGE-CURRENT-
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
150pF
RC
50M TO 100M
RD
330
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
tr = 0.7ns TO 1ns 30ns
60ns
t
100%
90%
10%
IPEAK
I
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
19
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
LDO
RS-485
TRANSCEIVER
VDDA
RXD
TXD
DE
A
B
VDDB
VLDO
GNDA GNDB
MAX14856
MAX14858
RE
ISOLATION BARRIER
uC
Z
Y
SBA
Typical Application Circuit
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
20
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Package Information
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+9 21-0042 90-0107
Ordering Information
PART TEMP RANGE PIN-PACKAGE
MAX14856GWE+ -40°C to +105°C 16 SOIC (W)
MAX14856GWE+T -40°C to +105°C 16 SOIC (W)
MAX14858GWE+ -40°C to +105°C 16 SOIC (W)
MAX14858GWE+T -40°C to +105°C 16 SOIC (W)
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and Reel.
MAX14856/MAX14858
www.maximintegrated.com Maxim Integrated
21
5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
Chip Information
PROCESS: BiCMOS
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 11/15 Initial release
1 1/17 Updated pending safety approvals 1, 7
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. © 2017 Maxim Integrated Products, Inc.
22
MAX14856/MAX14858 5kVRMS Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers
with ±35kV ESD Protection
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.

Products related to this Datasheet

IC TRANSCEIVER FULL 1/1 16SOIC
IC TRANSCEIVER FULL 1/1 16SOIC
EVAL KIT FOR MAX148
IC TRANSCEIVER FULL 1/1 16SOIC
IC TRANSCEIVER FULL 1/1 16SOIC