EVALUATION KIT AVAILABLE
MAX14853/MAX14855
2.75kV
RMS
Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers with ±35kV ESD
Protection and Integrated Transformer Driver
●
Higher Integration Simplifies Designs
• Integrated LDO for Powering Cable Side
• Integrated Transformer Driver for Power Transfer to
Cable Side
●
High-Performance Transceiver Enables Flexible
Designs
• Compliant with RS-485 EIA/TIA-485 Standard
• 500kbps (MAX14853)/25Mbps (MAX14855)
Maximum Data Rate
• Up to 128 Devices on the Bus
• Slew-Rate Limited Outputs (MAX14853)
• Integrated Receiver Deglitch Filter Increases Noise
Immunity (MAX14853)
●
Integrated Protection Ensures for Robust
Communication
• ±35kV ESD (HBM) on Driver Outputs/Receiver
Inputs
• 2.75kV
RMS
Withstand Isolation Voltage for 60s (V
ISO
)
• 630V
PEAK
Maximum Repetitive Peak Isolation
Voltage (V
IORM
)
• 445V
RMS
Maximum Working Isolation Voltage
(V
IOWM
)
• > 30 Years Lifetime at Rated Working Voltage
• Withstands ±10kV Surge per IEC 61000-4-5
• Thermal Shutdown
General Description
The
MAX14853/MAX14855
isolated
RS-485/
RS-422 transceivers provide 2750V
RMS
(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 (MAX14853) or 25Mbps
(MAX14855).
The MAX14853/MAX14855 include 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 MAX14853/MAX14855 include one drive channel
and one receive channel. The receiver is ¼-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 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 MAX14853/MAX14855 are available in a wide body
16-pin SOIC package and operate over the -40°C to
+105°C temperature range.
Benefits and Features
Functional Diagram
V
DDA
TD1 TD2
V
LDO
MAX14853
MAX14855
V
DDB
A
RS-485
TRANSCEIVER
Applications
●
●
●
●
Industrial Automation Equipment
Programmable Logic Controllers
HVAC
Power Meters
XFMR
DRIVER
LDO
Safety Regulatory Approvals
●
UL According to UL1577
●
cUL According to CSA Bulletin 5A
RE
RXD
TXD
DE
B
Z
Y
Ordering Information
appears at end of data sheet.
GNDA
GNDB
19-7546; Rev 5; 10/17
MAX14853/MAX14855
2.75kV
RMS
Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers with ±35kV ESD
Protection and Integrated Transformer Driver
Absolute Maximum Ratings
V
DDA
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
to GNDA ...........................................-0.3V to +6V
RXD to GNDA......................................... -0.3V to (V
DDA
+ 0.3V)
A, B, Y, Z to GNDB ...................................................-8V to +13V
TD1, TD2 Continuous Current .............................................1.4A
Short-Circuit Duration (RXD to GNDA, A, B, Y, Z,
VDDB to GNDB) ...................................................Continuous
Continuous Power Dissipation (T
A
= +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
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 (θ
JA
) ..............71°C/W
Junction-to-Case Thermal Resistance (θ
JC
) ...................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
(V
DDA
- V
GNDA
= 3.0V to 5.5V, V
DDB
- V
GNDB
= 3.0V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
V
DDA
- V
GNDA
= 3.3V, V
DDB
- V
GNDB
= 3.3V, V
GNDA
= V
GNDB
, and T
A
= +25°C.) (Notes 2, 3)
PARAMETER
POWER
Supply Voltage
V
DDA
V
DDB
I
DDA
Supply Current
I
DDB
Undervoltage Lockout
Threshold
Undervoltage Lockout
Threshold Hysteresis
TRANSFORMER DRIVER
Output Resistance
TD1, TD2 Current Limit
Switching Frequency
Duty Cycle
Crossover Dead Time
R
O
I
LIM
f
SW
D
tDEAD
TD1/TD2 = low, IOUT = 300mA
4.5V ≤ V
DDA
≤ 5.5V
3.0V ≤ V
DDA
≤ 3.6V
540
485
350
0.6
785
730
450
50
50
1.5
1300
1170
550
Ω
mA
kHz
%
ns
V
UVLOA
V
UVLOB
V
UVHYSTA
V
UVHYSTB
RE,
RXD, DE, TXD
TD1/TD2 driver
VDDA = 5V, DE = high,
RE
= TXD =
low, RXD unconnected, no load,
TD1/TD2 unconnected
DE = high,
RE
= TXD = low, RXD
unconnected, no load, VDDB = 3.3V
RE,
RXD, DE, TXD
TD1/TD2 driver
1.50
2.55
2.55
3.0
3.0
4.7
7.4
1.58
2.7
2.7
50
200
200
mV
5.5
5.5
7.7
mA
12.5
1.65
2.85
2.85
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
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Maxim Integrated
│
2
MAX14853/MAX14855
2.75kV
RMS
Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers with ±35kV ESD
Protection and Integrated Transformer Driver
DC Electrical Characteristics (continued)
(V
DDA
- V
GNDA
= 3.0V to 5.5V, V
DDB
- V
GNDB
= 3.0V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
DDA
- V
GNDA
= 3.3V, V
DDB
- V
GNDB
= 3.3V, V
GNDA
= V
GNDB
, and T
A
= +25°C.) (Notes 2, 3)
PARAMETER
LDO
LDO Supply Voltage
LDO Supply Current
LDO Output Voltage
LDO Current Limit
Load Regulation
Line Regulation
Dropout Voltage
LOGIC INTERFACE (TXD, RXD, DE,
RE)
Input High Voltage
Input Low Voltage
Input Hysteresis
Input Capacitance
Input Pullup Current
Input Pulldown Current
Output Voltage High
Output Voltage Low
Short-Circuit Output Pullup
Current
Short-Circuit Output Pulldown
Current
Three-State Output Current
DRIVER
RL
= 54Ω, TXD = high or low,
Figure 1a
RL
= 100Ω, TXD = high or low,
Figure 1a
-7V ≤V
CM
≤ +12V,
Figure 1b
Change in Magnitude of Differ-
ential Driver Output Voltage
Driver Common-Mode Output
Voltage
ΔV
OD
VOC
RL
= 100Ω or 54Ω,
Figure 1a
(Note 6)
RL
= 100Ω or 54Ω,
Figure 1a
(Note 6)
V
DDB
/
2
1.5
2.0
1.5
5
0.2
3
V
V
V
VIH
VIL
VHYS
CIN
IPU
IPD
VOH
VOL
ISH_PU
ISH_PD
IOZ
Load Capacitance
VLDO = 3.3V, ILOAD = -20mA
VLDO = 3.3V, ILOAD = -20mA
VLDO = 3.18V, IDDB = -120mA
Nominal value (Note 5)
1
0.7 x
VDDA
0.8
220
2
-10
1.5
VDDA
-0.4
0.4
6.4
5.5
-1
42
40
+1
-4.5
4.5
-1.5
10
VLDO
ILDO
VDDB
Relative to GNDB, LDO is on (Note 4)
DE = high,
RE
= TXD = low, no load,
V
LDO
= 5.5V
3.0
3.18
7.5
3.3
300
0.19
0.12
100
1.7
1.8
180
10
14
12.9
3.6
V
mA
V
mA
mV/mA
mV/V
mV
µF
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RE,
TXD, DE to GNDA
RE,
TXD, DE to GNDA
RE,
TXD, DE to GNDA
RE,
TXD, DE, f = 1MHz
TXD
DE,
RE
RXD to GNDA, IOUT = -4mA
RXD to GNDA, IOUT = 4mA
0V ≤ V
RXD
≤ V
DDA,
RE
= low
0V ≤ V
RXD
≤ V
DDA,
RE
= low
0V ≤ V
RXD
≤ V
DDA,
RE
= high
V
V
mV
pF
µA
µA
V
V
mA
mA
µA
Differential Driver Output
|VOD|
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Maxim Integrated
│
3
MAX14853/MAX14855
2.75kV
RMS
Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers with ±35kV ESD
Protection and Integrated Transformer Driver
DC Electrical Characteristics (continued)
(V
DDA
- V
GNDA
= 3.0V to 5.5V, V
DDB
- V
GNDB
= 3.0V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
DDA
- V
GNDA
= 3.3V, V
DDB
- V
GNDB
= 3.3V, V
GNDA
= V
GNDB
, and T
A
= +25°C.) (Notes 2, 3)
PARAMETER
Change in Magnitude of
Common-Mode Voltage
Driver Short-Circuit Output
Current
Single-Ended Driver Output
Voltage High
Single-Ended Driver Output
Voltage Low
Differential Driver Output
Capacitance
RECEIVER
Input Current (A and B)
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis
Receiver Input Resistance
Differential Input Capacitance
PROTECTION
Thermal-Shutdown Threshold
Thermal-Shutdown Hysteresis
T
SHDN
T
HYST
Human Body Model
ESD Protection
(A, B, Y, Z Pins to GNDB)
IEC 61000-4-2 Air-Gap Discharge to
GND
IEC 61000-4-2- Contact Discharge to
GND
Human Body Model
Human Body Model
Temperature rising
+160
15
±35
±18
±8
±8
±4
kV
kV
kV
°C
°C
IA, IB
VTH
ΔV
TH
RIN
CA,B
DE = GNDA,
VDDB = VGNDB
or 3.6V
-7V ≤ V
CM
≤ +12V
VCM = 0V
-7V ≤ V
CM
≤ +12V, DE = low
Measured between A and B,
DE =
RE
= GNDA at 2MHz
48
12
VIN = +12V
VIN = -7V
-200
-200
-120
20
-10
+250
µA
mV
mV
kΩ
pF
SYMBOL
ΔV
OC
CONDITIONS
RL
= 100Ω or 54Ω,
Figure 1a
(Note 5)
GNDB ≤ V
OUT
≤ +12V, output low
(Note 7)
-7V ≤ V
OUT
≤ V
DDB, output high
(Note 7)
Y and Z outputs, IY,Z = -20mA
Y and Z outputs, IY,Z = +20mA
DE =
RE
= high, f = 4MHz
12
+30
-250
2.2
0.8
MIN
TYP
MAX
0.2
+250
mA
-30
V
V
pF
UNITS
V
IOSD
VOH
VOL
COD
ESD Protection
(A, B, Y, Z, GNDB Pins to
GNDA)
ESD Protection (All Other Pins)
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Maxim Integrated
│
4
MAX14853/MAX14855
2.75kV
RMS
Isolated 500kbps/25Mbps Full-Duplex
RS-485/RS-422 Transceivers with ±35kV ESD
Protection and Integrated Transformer Driver
Switching Electrical Characteristics (MAX14853)
(V
DDA
- V
GNDA
= 3.0V to 5.5V, V
DDB
- V
GNDB
= 3.0V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
DDA
- V
GNDA
= 3.3V, V
DDB
- V
GNDB
= 3.3V, V
GNDA
= V
GNDB
, and T
A
= +25°C.) (Note 5)
PARAMETER
DYNAMIC
Common-Mode Transient
Immunity
Glitch Rejection
DRIVER
Driver Propagation Delay
Differential Driver Output Skew
|tDPLH - tDPHL|
Driver Differential Output Rise
or Fall Time
Maximum Data Rate
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time From Low
Driver Disable Time From High
RECEIVER
Receiver Propagation Delay
Receiver Output Skew
Maximum Data Rate
Receiver Enable to Output
High
Receiver Enable to Output Low
Receiver Disable Time From
Low
Receiver Disable Time From
High
tRPLH, tRPHL
tRSKEW
DRMAX
tRZH
tRZL
tRLZ
tRHZ
RL
= 1kΩ, C
L = 15pF, S2 closed,
Figure 8
RL
= 1kΩ, C
L = 15pF, S1 closed,
Figure 8
RL
= 1kΩ, C
L = 15pF, S1 closed,
Figure 8
RL
= 1kΩ, C
L = 15pF, S2 closed,
Figure 8
CL = 15pF,
Figure 6
and
Figure 7
(Note 9)
CL = 15pF,
Figure 6
and
Figure 7
(Note 9)
500
20
30
20
20
240
34
ns
ns
kbps
ns
ns
ns
ns
tDPLH, tDPHL
tDSKEW
tLH, tHL
DRMAX
tDZH
tDZL
tDLZ
tDHZ
RL
= 110Ω, C
L = 50pF,
Figure 4
RL
= 110Ω, C
L = 50pF,
Figure 5
RL
= 110Ω, C
L = 50pF,
Figure 5
RL
= 110Ω, C
L = 50pF,
Figure 4
RL
= 54Ω, C
L = 50pF,
Figure 2
and
Figure 3
RL
= 54Ω, C
L = 50pF,
Figure 2
and
Figure 3
R
L
= 54Ω, C
L = 50pF,
Figure 2
and
Figure 3
500
2540
2540
140
140
1040
144
900
ns
ns
ns
kbps
ns
ns
ns
ns
CMTI
(Note 8)
TXD, DE, RXD
10
35
17
29
kV/μs
ns
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
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Maxim Integrated
│
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