MXL1535ECWI+T [MAXIM]
Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, BICMOS, PDSO28, SOIC-28;型号: | MXL1535ECWI+T |
厂家: | MAXIM INTEGRATED PRODUCTS |
描述: | Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, BICMOS, PDSO28, SOIC-28 |
文件: | 总25页 (文件大小:792K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
19-3270; Rev 0; 4/04
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
General Description
Features
♦ 2500V
RS-485 Bus Isolation Using On-Chip
RMS
The MAX3535E/MXL1535E isolated RS-485/RS-422 full-
duplex transceivers provide 2500V of galvanic isola-
High-Voltage Capacitors
RMS
tion between the RS-485/RS-422 side and the processor
or control logic side. These devices allow fast,
1000kbps communication across an isolation barrier
when the common-mode voltages (i.e., the ground
potentials) on either side of the barrier are subject to
large differences. Isolation is achieved through integrat-
ed high-voltage capacitors. The MAX3535E/MXL1535E
also feature a 420kHz transformer driver that allows
power transfer to the RS-485 side using an external
transformer.
♦ 1000kbps Full-Duplex RS-485/RS-422
Communication
♦ +3V to +5.5V Power-Supply Voltage Range
(MAX3535E)
♦ +4.5V to +5.5V Power-Supply Voltage Range
(MXL1535E)
♦ 1/8 Unit Receiver Load, Allowing 256 Devices on
Bus
♦
15kV ESD Protection Using HBM
♦ Pin-Selectable Slew-Rate Limiting Controls EMI
♦ Hot-Swap-Protected Driver-Enable Input
♦ Undervoltage Lockout
The MAX3535E/MXL1535E include one differential driver,
one receiver, and internal circuitry to send the RS-485
signals and control signals across the isolation barrier
(including the isolation capacitors). The MAX3535E/
MXL1535E RS-485 receivers are 1/8 unit load, allowing
up to 256 devices on the same bus.
♦ Isolation-Barrier Fault Detection
♦ Short-Circuit Protected
♦ Thermal Shutdown
The MAX3535E/MXL1535E feature true fail-safe circuitry.
The driver outputs and the receiver inputs are protected
from 15kV electrostatic discharge (ESꢀ) on the inter-
face side, as specified in the Human Body Model (HBM).
♦ Open-Line and Shorted-Line Fail-Safe Receiver
Inputs
Ordering Information
The MAX3535E/MXL1535E feature driver slew-rate
select that minimizes electromagnetic interference (EMI)
and reduces reflections. The driver outputs are short-cir-
cuit and overvoltage protected. Other features are hot-
swap capability and isolation-barrier fault detection.
POWER-
SUPPLY
RANGE
(V)
PIN-
PACKAGE
PART
TEMP RANGE
+3.0 to +5.5
+3.0 to +5.5
+4.5 to +5.5
+4.5 to +5.5
MAX3535ECWI 0°C to +70°C 28 Wide SO
MAX3535EEWI -40°C to +85°C 28 Wide SO
MXL1535ECWI 0°C to +70°C 28 Wide SO
The MAX3535E operates with a single +3V to +5.5V
power supply. The improved secondary supply range of
the MAX3535E allows the use of step-down transformers
for +5V operation, resulting in considerable power sav-
ings. The MXL1535E operates with a single +4.5V to
+5.5V power supply. The MXL1535E is a function-/pin-
compatible improvement of the LTC1535. The
MAX3535E/MXL1535E are available over the commer-
cial 0°C to +70°C and extended -40°C to +85°C temper-
ature ranges.
MXL1535EEWI -40°C to +85°C
28 Wide SO
ꢁin Configuration
TOP VIEW
V
1
2
3
4
28 RO1
27 RE
26 DE
25 DI
CC1
ST1
ST2
Applications
GND1
Isolated RS-485 Systems
Systems with Large Common-Mode Voltages
Industrial-Control Local Area Networks
Telecommunications Systems
MAX3535E
MXL1535E
GND2 11
18 SLO
17 RO2
Z
12
13
14
Y
16
15
A
B
Typical Application Circuit appears at end of data sheet.
V
CC2
WIDE SO
PINS 5–10 and 19–24 ARE REMOVED FROM THE PACKAGE
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
ABSOLUTE MAXIMUM RATINGS
Logic Side—All Voltages Referenced to GNꢀ1.
.........................................................................-0.3V to +6V
Y, Z Maximum Current.............................Short-Circuit Protected
ST1, ST2 Maximum Current............................................ 300mA
V
CC1
RE, ꢀE, ꢀI.................................................................-0.3V to +6V
Continuous Power ꢀissipation (T = +70°C)
28-Pin Wide SO
(derate 9.5mW/°C above +70°C).................................750mW
Operating Temperature Range
A
RO1, ST1, ST2 ..........................................-0.3V to (V
Isolated Side—All Voltages Referenced to GNꢀ2.
+ 0.3V)
CC1
V
.........................................................................-0.3V to +8V
CC2
SLO...........................................................-0.3V to (V
+ 0.3V)
MXL1535ECWI, MAX3535ECWI .........................0°C to +70°C
MXL1535EEWI, MAX3535EEWI.......................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
CC2
A, B ...................................................................................... 14V
RO2 .....................-0.3V to the lower of (V + 0.3V) and +3.4V
CC2
Y, Z ............................................................................-8V to +13V
ꢀigital Outputs Maximum Current
RO1, RO2 ..................................................................... 20mA
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.
DC ELECTRICAL CHARACTERISTICS TABLE (MAX3535E)
(V
= +3.0V to +5.5V, V
= +3.13V to +7.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at V
CC1
= +3.3V,
UNITS
V
CC1
CC2
A
V
= +5V, T = +25°C.)
CC2
A
PARAMETER
SYMBOL
, GND1)
CONDITIONS
MIN
TYP
MAX
LOGIC-SIDE SUPPLY (V
CC1
Logic-Side Supply Voltage
V
3.0
5.5
13
CC1
Transformer not driven, ST1 and ST2
Logic-Side Supply Current
I
unconnected, RE = low, ꢀE = high,
5.9
mA
CC1
f
= 0, RO1 = no load
ꢀATA
V
Undervoltage-Lockout
CC1
V
2.53
2.63
2.69
2.80
2.85
2.97
V
V
UVL1
Falling Trip
V
Undervoltage-Lockout
CC1
V
UVH1
Rising Trip
LOGIC INPUTS (DI, DE, RE)
Input High Voltage, ꢀE, ꢀI, RE
Input Low Voltage, ꢀE, ꢀI, RE
Logic-Side Input Current, ꢀE, ꢀI
LOGIC OUTPUTS (RO1, RE)
V
V
V
is measured with respect to GNꢀ1
is measured with respect to GNꢀ1
2.0
V
V
IH
IH
IL
V
0.8
2
IL
I
µA
INC
I
I
I
I
= 4mA, V
= 4mA, V
= +4.5V
= +3V
3.7
2.4
SOURCE
CC1
CC1
Receiver-Output High Voltage
(RO1)
V
V
RO1H
SOURCE
= 4mA, V
= +4.5V
= +3V
0.4
0.4
SINK
SINK
CC1
Receiver-Output Low Voltage
(RO1)
V
V
RO1L
= 4mA, V
CC1
Receiver-Output (RO1) Leakage
Current
RE = high, V
= +5.5V,
CC1
I
1
µA
µA
OZR
0 ≤ V
≤ V
CC1
RO1
RE Low Output Current for Fault
ꢀetect
I
RE = +0.4V, fault not asserted
40
60
80
OL
2
_______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
DC ELECTRICAL CHARACTERISTICS TABLE (MAX3535E) (continued)
(V
= +3.0V to +5.5V, V
= +3.13V to +7.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at V = +3.3V,
CC1
CC1
CC2
A
V
= +5V, T = +25°C.)
CC2
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RE High Output Current for Fault
ꢀetect
I
RE = V
- 0.5V, fault asserted
-140
-100
-60
µA
OH
CC1
TRANSFORMER DRIVER (ST1, ST2)
ꢀC-Converter Switching
Frequency (ST1, ST2)
f
ST1, ST2, not loaded
290
460
590
kHz
SW
V
V
= +4.5V, Figure 13
= +3V, Figure 13
1.6
1.8
50
2.6
2.9
56
CC1
CC1
ꢀC-Converter Total Impedance
R
OHL
Ω
R
OH
+ R (ST1, ST2)
OL
ST1, ST2 ꢀuty Cycle
ST1, ST2, not loaded
44
%
ISOLATED-SIDE SUPPLY (V , GND2)
CC2
Isolated-Side Supply Voltage
V
3.13
7.50
70
V
CC2
f
= 0, SLO floating,
R = 27Ω
56
10
ꢀATA
L
Isolated-Side Supply Current
I
RO2 = no load,
A, B floating, Figure 1
mA
CC2
R = ∞
L
16
V
Undervoltage-Lockout
CC2
V
2.68
2.77
2.85
2.95
3.02
V
V
UVL2
Falling Trip
V
Undervoltage-Lockout
CC2
V
3.13
4
UVH2
Rising Trip
DRIVER OUTPUTS (Y, Z)
No load, V
GNꢀ2
is measured with respect to
ꢀOH
ꢀriver-Output High Voltage
ꢀifferential ꢀriver Output
V
V
V
ꢀOH
R = 50Ω (RS-422), V
= +3.13V,
= +3.13V,
L
CC2
2.0
1.5
1.0
2.35
1.95
Figure 1
V
Oꢀ
OC
R = 27Ω (RS-485), V
L
CC2
Figure 1
ꢀriver Common-Mode Output
Voltage
R = 27Ω or 50Ω, V
is measured with
L
OC
V
3.0
0.2
V
V
respect to GNꢀ2, Figure 1
Change in Magnitude of ꢀriver
ꢀifferential Output Voltage for
Complementary Output States
∆V
∆V
R = 27Ω or 50Ω, Figure 1
L
Oꢀ
OC
Change in Magnitude of ꢀriver
Common-Mode Output Voltage
for Complementary Output States
R = 27Ω or 50Ω, Figure 1
L
0.2
V
ꢀriver enabled (ꢀE =1 )
ꢀI = high, V > -7V
-250
Y
ꢀI = low, V > -7V
Z
ꢀriver Short-Circuit Output
Current
I
mA
OSꢀ
ꢀriver enabled (ꢀE =1 )
ꢀI = high, V < +12V
Z
+250
ꢀI = low, V < +12V
Y
_______________________________________________________________________________________
3
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
DC ELECTRICAL CHARACTERISTICS TABLE (MAX3535E) (continued)
(V
= +3.0V to +5.5V, V
= +3.13V to +7.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C,
CC1
CC2
A
A
V
= +3.3V, V
= +5V).
CC1
CC2
PARAMETER
SYMBOL
CONDITIONS
ꢀI = high
MIN
TYP
MAX
UNITS
-7V < V < min[(V
Y
- 1V) +2V]
- 1V) +2V]
CC2
-25
ꢀI = low
-7V < V < min[(V
Z
ꢀriver
enabled
(ꢀE =1)
CC2
ꢀriver Short-Circuit Foldback
Output Current
I
µA
OSFꢀ
ꢀI = high
+1V < V < +12V
Z
+25
3.0
ꢀI = low
+1V < V < +12V
Y
SLEW-RATE SELECT (SLO)
Input High Voltage SLO
Input Low Voltage SLO
SLO Pullup Resistor
V
V
V
V
is measured with respect to GNꢀ2
is measured with respect to GNꢀ2
V
V
IHS
IHS
ILS
V
1.0
ILS
R
SLO
= +3V
100
-90
kΩ
SLO
RECEIVER INPUTS (A, B)
V
V
or V = +12V
+125
-100
A
A
B
Receiver Input Current
I
µA
AB
or V = -7V
B
Receiver ꢀifferential Threshold
Voltage
V
-7V ≤ V
-7V ≤ V
≤ +12V
-200
-10
mV
TH
CM
≤ +12V, T = 0°C to +70°C
10
5
30
30
70
70
CM
CM
A
Receiver-Input Hysteresis
Receiver-Input Resistance
∆V
mV
kΩ
V
TH
-7v ≤ V
-7V ≤ V
≤ +12V, T = -40°C to +85°C
A
R
≤ +12V (Note 1)
96
200
IN
CM
Receiver-Input Open Circuit
Voltage
V
2.6
OAB
RECEIVER OUTPUT (RO2)
Receiver-Output (RO2) High
Voltage
V
I
I
= 4mA, V = +3.13V
CC2
2.4
V
V
RO2H
SOURCE
Receiver-Output (RO2) Low
Voltage
V
= 4mA, V = +3.13V
CC2
0.4
RO2L
SINK
ISOLATION
60s
1s
2500
3000
100
Isolation Voltage (Notes 2, 3)
V
V
RMS
ISO
Isolation Resistance
Isolation Capacitance
ESꢀ Protection
R
T
A
T
A
= +25°C, V
= +25°C
= 50V (Note 3)
ISO
10,000
MΩ
pF
ISO
ISO
C
2
Human Body Model (A, B, Y, Z)
15
kV
4
_______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
SWITCHING ELECTRICAL CHARACTERISTICS (MAX3535E)
(V
are at V
= +3.0V to +5.5V, V
= +3.13V to +7.5V, R = 27Ω, C = 50pF, T = -40°C to +85°C, unless otherwise noted. Typical values
CC1
CC2
L
L
A
= +3.3V, V
= +5V, T = +25°C.)
CC1
CC2 A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ꢀata Sample Jitter
t
Figure 6
220
285
ns
J
t = 25% of data cell, receiver and driver,
J
SLO = high (Note 4)
Maximum ꢀata Rate
f
877
1136
kbps
kHz
ns
ꢀATA
SLO = high, Figure 5
SLO = low, Figure 5
250
200
450
375
490
850
30
Self-Oscillating Frequency
f
SOS
SLO = high, Figures 2, 6
SLO = low, Figures 2, 6
SLO = high, Figures 2, 6
SLO = low, Figures 2, 6
855
1560
100
ꢀriver-ꢀifferential Output ꢀelay
Time
t
ꢀꢀ
ꢀriver-ꢀifferential Output
Transition Time
t
Tꢀ
ns
120
220
1000
SLO = high, ꢀI = high or low,
Figures 3, 7
ꢀriver-Output Enable Time
ꢀriver-Output ꢀisable Time
t
t
, t
730
720
440
1400
1300
855
ns
PZL PZH
SLO = high, ꢀI = high or low,
Figures 3, 7
, t
ns
PHZ PLZ
Receiver-Propagation ꢀelay Time
to RO1
t
t
,
PLH1
Figures 4, 8
ns
PHL1
Receiver-Propagation ꢀelay Time
to RO2
t
t
,
PLH2
Figures 4, 8
Figures 4, 8
Figures 4, 9
40
40
30
ns
ns
ns
PHL2
RO1, RO2 Rise or Fall Time
t , t
R F
Receiver-Output Enable Time
RO1
t
t
,t
ZL ZH
Receiver-Output ꢀisable Time
RO1
,t
Figures 4, 9
(Note 5)
30
ns
ns
ns
LZ HZ
Initial Startup Time (from Internal
Communication Fault)
1200
1200
Internal Communication Timeout
Fault Time
(Note 5)
_______________________________________________________________________________________
5
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
ELECTRICAL CHARACTERISTICS (MXL1535E)
(V
= +4.5V to +5.5V, V
= +4.5V to +7.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at V
= +5V,
CC1
CC1
CC2
A
V
= +5V, T = +25°C.)
CC2
A
PARAMETER
SYMBOL
CONDITIONS
MIN
4.5
TYP
MAX
5.5
UNITS
Logic-Side Supply Voltage
Isolated-Side Supply Voltage
V
V
V
V
CC1
CC2
4.5
7.5
Transformer not driven, ST1 and ST2
Logic-Side Supply Current
Isolated-Side Supply Current
I
I
unconnected, RE = low, ꢀE = high,
5.9
13
mA
mA
CC1
CC2
f
= 0, RO1 = no load
ꢀATA
f
= 0, SLO floating,
R = 27Ω
L
56
10
70
16
ꢀATA
RO2 = no load, A, B
floating, Figure 1
R = ∞
L
R = 50Ω (RS-422), V
= +4.5V, Figure 1
= +4.5V, Figure 1
2.0
1.5
3.0
2.5
L
CC2
ꢀifferential ꢀriver Output
ꢀriver Output High Voltage
V
V
V
V
Oꢀ
R = 27Ω (RS-485), V
L
CC2
No load, V
GNꢀ2
is measured with respect to
ꢀOH
V
5.0
3.0
ꢀOH
ꢀriver Common-Mode Output
Voltage
R = 27Ω or 50Ω, V
is measured with
L
OC
V
1.0
OC
respect to GNꢀ2, Figure 1
Change in Magnitude of ꢀriver
ꢀifferential Output Voltage for
Complementary Output States
∆V
∆V
R = 27Ω or 50Ω, Figure 1
0.2
0.2
V
V
Oꢀ
OC
L
Change in Magnitude of ꢀriver
Common-Mode Output Voltage
for Complementary Output States
R = 27Ω or 50Ω, Figure 1
L
ꢀriver enabled (ꢀE =1)
ꢀI = high, V > -7V
Y
-250
ꢀI = low, V > -7V
Z
ꢀriver Short-Circuit Output
Current
I
mA
OSꢀ
ꢀriver enabled (ꢀE =1)
ꢀI = high, V < +12V
ꢀI = low, V < + 12V
Y
+250
-25
Z
ꢀriver enabled (ꢀE =1)
ꢀI = high
-7V < V < min[(V
Y
- 1V) +2V]
CC2
ꢀI = low
-7V < V < min[(V
- 1V) +2V]
Z
CC2
ꢀriver Short-Circuit Foldback
Output Current
I
mA
OSFꢀ
ꢀriver enabled (ꢀE =1)
ꢀI = high
+1V < V < +12V
Z
+25
ꢀI = low
+1V < V < +12V
Y
6
_______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
ELECTRICAL CHARACTERISTICS (MXL1535E) (continued)
(V
= +4.5V to +5.5V, V
= +4.5V to +7.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at V
= +5V,
CC1
CC1
CC2
A
V
= +5V, T = +25°C.)
CC2
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Input High Voltage, ꢀE, ꢀI, RE
Input High Voltage, SLO
V
V
V
V
V
is measured with respect to GNꢀ1
2.0
1.45
V
IH
IH
V
is measured with respect to GNꢀ2
4.0
2.1
1.45
2.1
V
V
IHS
IHS
Input Low Voltage, ꢀE, ꢀI, RE
Input Low Voltage, SLO
V
is measured with respect to GNꢀ1
0.8
1.0
2
IL
ILS
INC
IL
V
is measured with respect to GNꢀ2
V
ILS
Logic-Side Input Current, ꢀE, ꢀI
Receiver Input Current
I
µA
mA
mV
V
V
or V = +12V
+0.25
-0.20
A
A
B
I
AB
or V = -7V
B
Receiver ꢀifferential Threshold
Voltage
V
-7V ≤ V
-7V ≤ V
≤ +12V
-200
10
-90
30
-10
70
TH
CM
CM
≤ +12V, T = 0°C to +70°C
A
Receiver-Input Hysteresis
Receiver-Input Resistance
∆V
mV
TH
-7V ≤ V
-7V ≤ V
≤ +12V, T = -40°C to +85°C
5
30
140
2.6
70
CM
CM
A
R
≤ +12V (Note 1)
96
200
kΩ
IN
Receiver-Input Open-Circuit
Voltage
V
V
OAB
Receiver-Output High Voltage
(RO1)
V
I
I
= 4mA, V = +4.5V
CC1
3.7
4.3
0.4
30
V
V
RO1H
SOURCE
Receiver-Output Low Voltage
(RO1)
V
= 4mA, V = +4.5V
CC1
0.8
RO1L
SINK
ꢀE = low
-7V < V < +12V, -7V < V < +12V
ꢀriver-Output Leakage Current
ꢀriver-Output Leakage Current
I
I
µA
µA
V
OZ
OZ
Y
Z
ꢀE = low
-7V < V < +12V, -7V < V < +12V
30
100
Y
Z
Receiver-Output (RO2) High
Voltage
V
I
= 4mA, V
= +4.5V
CC2
2.8
3.4
0.4
460
RO2H
SOURCE
Receiver-Output (RO2) Low
Voltage
V
I = 4mA, V
SINK
= +4.5V
0.8
V
RO2L
CC2
ꢀC-Converter Switching
Frequency (ST1, ST2)
f
ST1, ST2 not loaded
290
590
kHz
SW
_______________________________________________________________________________________
7
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
ELECTRICAL CHARACTERISTICS (MXL1535E) (continued)
(V
= +4.5V to +5.5V, V
= +4.5V to +7.5V, T = -40°C to +85°C, unless otherwise noted. Typical values are at V
= +5V,
CC1
CC1
CC2
A
V
= +5V, T = +25°C.)
CC2
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ꢀC-Converter Impedance High
ST1, ST2
R
Figure 13
Figure 13
4
6
Ω
OH
ꢀC-Converter Impedance Low
ST1, ST2
R
2.5
-50
5
Ω
µA
µA
V
OL
OL
RE Low Output Current for Fault
ꢀetect
RE = sink current,
RE = +0.4V, fault not asserted
I
-40
60
-80
RE High Output Current for Fault
ꢀetect
RE = source current,
I
100
2.85
2.95
2.69
2.80
140
3.02
3.13
2.85
2.97
OH
RE = +V
- 0.5V, fault asserted
CC1
V
Undervoltage-Lockout
CC2
V
2.68
2.77
2.53
2.63
UVL2
Falling Trip
V
Undervoltage-Lockout
CC2
V
V
UVH2
Rising Trip
V
Undervoltage-Lockout
CC1
V
V
UVL1
Falling Trip
V
Undervoltage-Lockout
CC1
V
V
UVH1
Rising Trip
60s
1s
2500
3000
Isolation Voltage (Note 2)
SLO Pullup Resistor
V
V
RMS
ISO
R
SLO
V
= +3V
SLO
100
kΩ
8
_______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
SWITCHING ELECTRICAL CHARACTERISTICS (MXL1535E)
(V
are at V
= +4.5V to +5.5V, V
= +4.5V to +7.5V, R = 27Ω, C = 50pF, T = -40°C to +85°C, unless otherwise noted. Typical values
CC1
CC2
L
L
A
= +5V, V = +5V, T = +25°C.)
CC2 A
CC1
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
220
450
430
850
45
MAX
UNITS
ns
ꢀata Sample Jitter
Max Baud Rate
t
Figure 6
285
J
f
SLO = high, Figure 5, (Note 6)
SLO = high, Figures 2, 6
SLO = low, Figures 2, 6
250
kBd
MAX
855
1560
100
ꢀriver-ꢀifferential Output ꢀelay
Time
t
ns
ns
ns
ns
ns
ꢀꢀ
SLO = high, V
= +4.5V
CC2
ꢀriver-ꢀifferential Output
Transition Time
t
Tꢀ
SLO = low, V
= +4.5V
150
260
1000
CC2
SLO = high, ꢀI = high or low,
ꢀriver-Output Enable Time
ꢀriver-Output ꢀisable Time
t
t
, t
730
720
440
1400
1300
855
PZL PZH
Figure 3, 7
SLO = high, ꢀI = high or low,
, t
PHZ PLZ
Figures 3, 7
Receiver-Propagation ꢀelay Time
to RO1
t ,
PLH1
Figures 4, 8
t
PHL1
Receiver-Propagation ꢀelay Time
to RO2
t
t
,
PLH2
Figures 4, 8
Figures 4, 8
Figures 4, 9
40
40
30
ns
ns
ns
PHL2
RO1, RO2 Rise or Fall Time
t , t
R F
Receiver-Output Enable Time
RO1
t
, t
ZL ZH
Receiver-Output ꢀisable Time
RO1
t
,t
Figures 4, 9
(Note 5)
30
ns
ns
ns
LZ HZ
Initial Startup Time (from Internal
Communication Fault)
1200
1200
Internal Communication Timeout
Fault Time
(Note 5)
0°C to +70°C
56
57
ST1, ST2 ꢀuty Cycle
ESꢀ Protection
%
-40°C to +85°C
Human Body Model (A, B, Y, Z)
15
kV
Note 1: Receiver inputs are 96kΩ minimum resistance, which is 1/8 unit load.
Note 2: 60s test result is guaranteed by correlation from 1s result.
Note 3:
V
is the voltage difference between GNꢀ1 and GNꢀ2.
ISO
Note 4: The maximum data rate is specified using the maximum jitter value according to the formula: data rate = 1 / (4t ). See the
J
Skew section for more information.
Note 5: Initial startup time is the time for communication to recover after a fault condition. Internal communication timeout fault time
is the time before a fault is indicated on RE, after internal communication has stopped.
Note 6: Bd = 2 bits.
_______________________________________________________________________________________
9
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
Typical Operating Characteristics
(V
= +5V, C = 50pF (Figure 1), unless otherwise noted.)
L
CC1
I
SUPPLY CURRENT
vs. TEMPERATURE
CC1
I
SUPPLY CURRENT
vs. TEMPERATURE
I
SUPPLY CURRENT
vs. TEMPERATURE
CC1
CC2
100
80
60
40
20
0
100
80
60
40
20
0
80
70
60
50
40
30
HALO
TGM-250NS
1:1:1 TRANSFORMER
HALO
TGM-240NS
1:1.3:1.3 TRANSFORMER
f
= 700kbps
DATA
V
= +3.3V
CC1
SLO = LOW
R = 27Ω
L
R = 27Ω
L
R = 27Ω
L
V
= +6V
CC2
R = 60Ω
L
R = 60Ω
L
V
= +3.9V
CC2
(MAX3535E)
R = OPEN
L
R = OPEN
L
V
= +3.13V
CC2
FIGURE 1
FIGURE 1
-15
FIGURE 1
-15
(MAX3535E)
-40
-15
10
35
60
85
-40
-40
-40
10
35
60
85
85
85
-40
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
SELF-OSCILLATION FREQUENCY
vs. TEMPERATURE
V
SUPPLY VOLTAGE
DRIVER DIFFERENTIAL OUTPUT
TRANSITION TIME vs. TEMPERATURE
CC2
vs. TEMPERATURE
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
500
450
400
350
300
250
100
90
80
70
60
50
40
30
20
10
0
V
= V
CC2
CC1
L
R = 27Ω
L
SLO = HIGH
R = OPEN, V
L
= +5V
R = 27Ω
CC1
SLO = V
CC2
R = 27Ω, V
L
= +5V
CC1
HALO
TGM-240NS
1:1.3:1.3 TRANSFORMER
SLO = LOW
V
= +5V
CC2
V
= +3.13V (MAX3535E)
FIGURES 2, 6
CC2
R = 27Ω, V
= +3V
L
CC1
(MAX3535E)
FIGURE 5
-15
FIGURE 1
60
-40
-15
10
35
85
10
35
60
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
SWITCHER FREQUENCY
vs. SUPPLY VOLTAGE
SWITCHER FREQUENCY
vs. TEMPERATURE
DRIVER DIFFERENTIAL OUTPUT
TRANSITION TIME vs. TEMPERATURE
600
550
500
450
400
350
300
600
550
500
450
400
350
300
800
700
600
500
400
300
200
R = 27Ω
SLO = GND2
L
V
= +5V
CC2
V
= +3.13V (MAX3535E)
CC2
FIGURES 2, 6
60 85
3.0
3.5
4.0
4.5
(V)
5.0
5.5
-15
10
35
60
-40
-15
10
35
V
TEMPERATURE (°C)
TEMPERATURE (°C)
CC1
10 ______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
Typical Operating Characteristics (continued)
(V
= +5V, C = 50pF (Figure 1), unless otherwise noted.)
CC1
L
RECEIVER-OUTPUT (RO1) HIGH VOLTAGE
vs. TEMPERATURE
RECEIVER-OUTPUT (RO1) LOW VOLTAGE
vs. TEMPERATURE
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. DIFFERENTIAL OUTPUT CURRENT
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.0
0.8
0.6
0.4
0.2
0
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
I
= 4mA
DE = HIGH
SINK
V
= +5V
CC1
V
= +3.9V
(MAX3535E)
CC2
V
= +4.5V
CC1
V
= +3.13V
CC2
V
= +3V
(MAX3535E)
CC1
(MAX3535E)
V
= +4.5V
CC1
V
= +7.5V
CC2
V
= +3V
CC1
(MAX3535E)
I
= 4mA
SOURCE
60
V
= +5V
CC1
-40
-15
10
35
85
-40
-15
10
35
60
85
0
20
40
60
80
100
120
TEMPERATURE (°C)
TEMPERATURE (°C)
DRIVER DIFFERENTIAL OUTPUT CURRENT (mA)
DRIVER-OUTPUT HIGH VOLTAGE
vs. DRIVER SOURCE CURRENT
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. V SUPPLY VOLTAGE
DRIVER-OUTPUT LOW VOLTAGE
vs. DRIVER SINK CURRENT
CC2
5
4
2.8
2.6
2.4
2.2
2.0
1.8
1.6
12
11
10
9
DE = HIGH
DE = HIGH
R = 27Ω
L
3
2
V
= +7.5V
CC2
1
V
= +3.13V
(MAX3535E)
8
CC2
0
7
V
= +3.9V
CC2
-1
-2
-3
-4
-5
-6
-7
6
(MAX3535E)
5
4
V
= +7.5V
V
= +3.13V
CC2
(MAX3535E)
CC2
3
2
V
= +3.9V
CC2
1
(MAX3535E)
FIGURE 1
0
0
20
40
60
80
100
120
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5
(V)
0
20
40
60
80
100
120
DRIVER SOURCE CURRENT (mA)
V
DRIVER SINK CURRENT (mA)
CC2
I
SUPPLY CURRENT
SUPPLY VOLTAGE
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
RECEIVER OUTPUT (RO1) VOLTAGE
vs. LOAD CURRENT
CC1
CC1
vs. V
10
9
8
7
6
5
4
3
2
1
0
5
4
3
2
1
0
5
4
3
2
1
0
R = OPEN
TRANSFORMER IS NOT DRIVEN
R = 27Ω
SLO = GND2
L
L
OUTPUT HIGH, SOURCING
V
= +7.5V
CC2
V
= +6V
CC2
V
= +3.13V
CC2
(MAX3535E)
OUTPUT LOW, SINKING
5
FIGURE 1
3.0
3.5
4.0
SUPPLY VOLTAGE (V)
CC1
4.5
5.0
5.5
0
10
15
-40
-15
10
35
60
85
V
LOAD CURRENT (mA)
TEMPERATURE (°C)
______________________________________________________________________________________ 11
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
Typical Operating Characteristics (continued)
(V
= +5V, C = 50pF (Figure 1), unless otherwise noted.)
L
CC1
RECEIVER (RO1) PROPAGATION DELAY
(t
DRIVER PROPAGATION DELAY
(SLO = HIGH)
DRIVER PROPAGATION DELAY
(SLO = LOW)
)
PLH1
MAX3535E toc19
MAX3535E toc21
MAX3535E toc20
A-B
1V/div
DI
2V/div
DI
2V/div
Y
Y
2V/div
2V/div
RO
1V/div
Z
Z
2V/div
2V/div
100ns/div
400ns/div
400ns/div
DRIVER ENABLE
TIME PLUS JITTER
JITTER vs. TEMPERATURE
MAX3535E toc23
300
280
260
240
220
200
DE
2V/div
Y
2V/div
V
V
= 3.13V
= 5.5V
CC1
CC1
-40
-15
10
35
60
85
200ns/div
TEMPERATURE (°C)
RECEIVER (RO1) PROPAGATION DELAY
(t
DRIVER DISABLE
TIME PLUS JITTER
)
PHL1
MAX3535E toc25
MAX3535E toc24
A-B
1V/div
DE
2V/div
Y
RO
1V/div
2V/div
100ns/div
200ns/div
12 ______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
ꢁin Description
PIN
NAME
ISOLATION SIDE
FUNCTION
Logic-Side/Transformer-ꢀriver Power Input. Bypass V
capacitors.
to GNꢀ1 with 10µF and 0.1µF
CC1
1
V
Logic
CC1
Transformer-ꢀriver Phase 1 Power Output. Connect ST1 to isolation-transformer
primary to send power to isolation side of barrier.
2
ST1
Logic
Transformer-ꢀriver Phase 2 Power Output. Connect ST2 to isolation-transformer
primary to send power to isolation side of barrier.
3
4
ST2
GNꢀ1
—
Logic
Logic
—
Logic-Side Ground. For isolated operation do not connect to GNꢀ2.
5–10,
19–24
Removed from Package
11
GNꢀ2
Z
Isolated
Isolated
Isolation-Side Ground. For isolated operation do not connect to GNꢀ1.
RS-485/RS-422 Inverting ꢀriver Output. Output floats when ꢀE is low or in a barrier fault
event. (See the Detailed Description section for more information.)
12
RS-485/RS-422 Noninverting ꢀriver Output. Output floats when ꢀE is low or in a barrier
fault event. (See the Detailed Description section for more information.)
13
14
Y
Isolated
Isolated
Isolated-Side Power Input. Connect V
to the rectified output of transformer
CC2
V
CC2
secondary. Bypass V
to GNꢀ2 with 10µF and 0.1µF capacitors.
CC2
15
16
B
A
Isolated
Isolated
RS-485/RS-422 ꢀifferential-Receiver Inverting Input
RS-485/RS-422 ꢀifferential-Receiver Noninverting Input
Isolated-Side Receiver Output. RO2 is always enabled. RO2 goes high if A - B > -10mV.
RO2 goes low if A - B < -200mV. Fail-safe circuitry causes RO2 to go high when A and B
float or are shorted.
17
RO2
Isolated
ꢀriver Slew-Rate Control Logic Input. Connect SLO to GNꢀ2 for data rates up to
18
25
SLO
Isolated
Logic
400kbps. Connect SLO to V
or leave floating for high data rates.
CC2
ꢀriver Input. Pull ꢀI low (high) to force driver output Y low (high) and driver output Z
high (low).
ꢀI
ꢀriver-Enable Input. The driver outputs are enabled and follow the driver input (ꢀI)
when ꢀE is high. When ꢀE is floated, the driver is disabled. ꢀE does not affect whether
the receiver is on or off.
26
27
28
ꢀE
RE
Logic
Logic
Logic
Receiver-Output Enable and Fault Current Output. The receiver output (RO1) is
enabled and follows the differential-receiver inputs, A and B, when RE is low, otherwise
RO1 floats. RE does not affect RO2 and does not disable the driver. The asserted fault
output is a pullup current, otherwise RE shows a pulldown current.
Receiver Output. RO1 is enabled when RE is low. RO1 goes high if A - B > -10mV. RO1
goes low if A - B < -200mV. Fail-safe circuitry causes RO1 to go high when A and B
float or are shorted.
RO1
______________________________________________________________________________________ 13
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
Test Circuits
Y
V
CC2
500Ω
500Ω
R
R
L
L
Y/Z
V
V
OC
OD
C
L
GND2
Z
Figure 1. Driver DC Test Load
Figure 3. Driver Timing Test Load
HIGH
V
/V
CC1 CC2
1kΩ
1kΩ
C
R
R
L
L
L
L
DE
Y
RO1/RO2
DI
C
L
Z
GND2
C
GND1/GND2
GND
Figure 4. Receiver Timing Test Load
Figure 2. Driver Timing Test Circuit
1/2
BAT54C
TGM-240
CONTROL GROUND
RS485 GROUND
0.1µF
10µF
1/2
BAT54C
ST1
ST2
TRANSFORMER
GND2
V
CC2
+3.0V TO +5.5V
V
CC1
DRIVER
VOLTAGE
REGULATOR
0.1µF
10µF
A
RO1
B
RECEIVER
RO2
RE
DE
DRIVER
Y
Z
2R
L
DI
V
CC2
C
C
L
L
MAX3535E
GND1
BARRIER
TRANSCEIVER
BARRIER
TRANSCEIVER
SLO
ISOLATION BARRIER
Figure 5. Self-Oscillating Configuration
14 ______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
Switching Waveforms
t
< 10ns, t < 10ns
F
R
t
< 10ns, t < 10ns
F
R
DI
1.5V
1.5V
V
- V
B
0V
0V
A
INPUT
t
t
DD
t
PHL1
DD
t
PLH1
t
PLH1
Z
V
V
/2
RO1H
RO1H
V
/2
RO1H
V
DOH
RO1
V
OUTPUT
Y
t
t
RO1L
J
J
1/2 V
DOH
RO2
V
DOH
0V
80%
80%
80%
V
= V - V
OD Y Z
80%
20%
20%
20%
20%
-V
DOH
t
t
PLH2
PLH2
t
t
TD
TD
t
t
R
F
t
J
Figure 8. Receiver Propagation Delays
Figure 6. Driver Propagation Delay
t
R
< 10ns, t < 10ns
F
1.5V
1.5V
PZL
DE
RE
1.5V
1.5V
t
< 10ns, t < 10ns
F
R
t
t
PLZ
V
DOH
Y, Z
t
t
LZ
ZL
V
RO1H
RO1
V
/2
V
+ 0.5V
- 0.5V
DOH
DOL
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
V
+ 0.5V
- 0.5V
RO1L
RO1H
V
DOL
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
V
RO1L
V
DOH
Y, Z
V
RO1H
RO1
0V
V
V
/2
DOH
DOH
V
0V
t
t
PHZ
PZH
t
HZ
t
ZH
2 x t
J
t
J
Figure 9. Receiver Enable and Disable Times
Figure 7. Driver Enable and Disable Times
______________________________________________________________________________________ 15
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
driver outputs are short-circuit protected for sourcing or
Detailed Description
sinking current and have overvoltage protection. Other
features include hot-swap capability, which holds the
driver off if the driver logic signals are floated after
power is applied. The MAX3535E/MXL1535E have
error-detection circuitry that alerts the processor when
there is a fault and disables the driver until the fault is
removed.
The MAX3535E/MXL1535E isolated RS-485/RS-422 full-
duplex transceivers provide 2500V
of galvanic isola-
RMS
tion between the RS-485/RS-422 isolation side and the
processor or logic side. These devices allow fast,
1000kbps communication across an isolation barrier even
when the common-mode voltages (i.e., the ground poten-
tials) on either side of the barrier are subject to large dif-
ferences. The isolation barrier consists of two parts. The
first part is a capacitive isolation barrier (integrated high-
voltage capacitors) that allows data transmission
between the logic side and the RS-485/RS-422 isolation
side. ꢀata is sampled and encoded before it is transmit-
ted across the isolation barrier introducing sampling jitter
and further delay into the communication system.
Fail Safe
The MAX3535E/MXL1535E guarantee a logic-high
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 (A - B) is greater than or equal to
-10mV, RO1 is logic-high (Table 2). In the case of a ter-
minated bus with all transmitters disabled, the receiv-
er’s differential input voltage is pulled to zero by the
termination. ꢀue to the receiver thresholds of the
MAX3535E/MXL1535E, this results in a logic-high at
RO1 with a 10mV minimum noise margin.
The second part of the isolation barrier consists of an
external transformer with the required primary-to-sec-
ondary isolation, allowing the transmission of operating
power from the logic side across the isolation barrier to
the isolation side. Connect the primary of the external
transformer to the MAX3535E/MXL1535E’s 420kHz
transformer driver outputs ST1 and ST2. Since the
MXL1535E and the MAX3535E operate with different
supply-voltage requirements at their respective isolated
and logic sides, different isolation transformers must be
used with each device (see the Transformer Selection
section). The only external components needed to
complete the system are the isolation transformer, two
diodes, and two low-voltage, 10µF decoupling capaci-
tors (see the Typical Application Circuit).
Driver Output ꢁrotection
Two mechanisms prevent excessive output current and
power dissipation caused by faults or by bus con-
tention. The first, a foldback current limit on the output
stage, provides immediate protection against short cir-
cuits 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 tempera-
ture exceeds +150°C.
The MAX3535E/MXL1535E include one differential dri-
ver, one receiver, and internal circuitry to send the RS-
485 signals and logic signals across the isolation barrier
(including the isolation capacitors). The MAX3535E/
MXL1535E receivers are 1/8 unit load, allowing up to 256
devices on a single bus.
Monitoring Faults on RE
RE functions as both an input and an output. As an
input, RE controls the receiver output enable (RO1). As
an output, RE is used to indicate when there are faults
associated with the operation of the part. This dual
functionality is made possible by using an output driver
stage that can easily be overdriven by most logic
gates. When an external gate is not actively driving RE,
it is driven either high using a 100µA internal pullup
current (fault present), or low using a 60µA internal pull-
down current (no fault). When using RE to control the
receiver-enable output function, be sure to drive it
using a gate that has enough sink and source capabili-
ty to overcome the internal drive.
The MAX3535E/MXL1535E feature fail-safe circuitry
ensuring the receiver output maintains a logic-high
state when the receiver inputs are open or shorted, or
when connected to a terminated transmission line with
all drivers disabled (see the Fail-Safe section).
The MAX3535E/MXL1535E feature driver slew-rate
select that minimizes electromagnetic interference
(EMI) and reduces reflections caused by improperly
terminated cables at data rates below 400kbps. The
16 ______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
When not actively driving RE, it functions as the fault
Read RE for fault conditions by using a bidirectional
microcontroller I/O line or a tri-stated buffer as shown in
Figure 10. When using a tri-stated buffer, enable the
driver whenever the voltage on RE needs to be forced
to a logic-high or logic-low. To read RE for a fault con-
dition, disable the driver.
indicator (Table 3). A low on RE indicates the part is
functioning properly, while a high indicates a fault is
present. The four causes of a fault indication are:
1) The voltage on V
is below its undervoltage-lock-
CC1
out threshold (2.69V nominal)
2) The voltage on V
is below its undervoltage-lock-
Slew-Rate Control Logic
The SLO input selects between a fast and a slow slew
rate for the driver outputs. Connecting SLO to GNꢀ2
selects the slow slew-rate option that minimizes EMI
and reduces reflections caused by improperly terminat-
ed cables at data rates up to 400kbps. This occurs
because lowering the slew rate decreases the rise and
fall times for the signal at the driver outputs, drastically
reducing the high-frequency components and harmon-
CC2
out threshold (2.80V nominal)
3) There is a problem that prevents the MAX3535E/
MXL1535E from communicating across its isolation
barrier
4) The die temperature exceeds +150°C nominally,
causing the part to go into thermal shutdown
When a fault occurs, RO1 is switched to a logic-high
state if RE is low (Table 3). Open-circuit or short-circuit
conditions on the receiver inputs do not generate fault
conditions; however, any such condition also puts RO1
in a logic-high state (see the Fail Safe section).
ics at the output. Floating SLO or connecting it to V
CC2
selects the fast slew rate, which allows high-speed
operation.
V
CC1
TRI-STATED BUFFER/
BIDIRECTIONAL MICROCONTROLLER I/O
V
CC1
RO1
RE
RE
D
OE
DRIVER OUTPUT BECOMES HIGH IMPEDANCE
MAX3535E
MXL1535E
OE
DE
DI
FAULT
FAULT DETECTED
FAULT
R
GND1
Figure 10. Reading a Fault Condition
______________________________________________________________________________________ 17
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
Functional Tables
Table 1. Transmitting Logic
TRANSMITTING LOGIC
INPUTS
OUTPUTS
DE
1
DI
1
Y
1
0
Z
0
1
0
1
0
X
High impedance
High impedance
Table 2. Receiving Logic
RECEIVING LOGIC
INPUTS
OUTPUTS
RE
0
V
- V
RO1
RO2
A
B
>-10mV
1
1
0
1
1
0
1
0
<-200mV
0
0
1
1
1
Inputs open/shorted
>-10mV
1
High impedance
High impedance
High impedance
<-200mV
Inputs open/shorted
Table 3. Fault Mode
NORMAL
MODE
FAULT MODES
FUNCTION
INTERNAL
COMMUNICATION
FAULT
V
CC1
V
CC2
> V
> V
V
CC1
V
CC2
< V
> V
V
V
> V
< V
V
CC1
V
CC2
< V
< V
THERMAL
SHUTDOWN
UVH1
UVH2
UVL1
UVH2
CC1
UVH1
UVL1
UVL2
CC2
UVL2
Transformer
driver
On
On
On
On
Off
On
(ST1, ST2)
RE = 0
Active
High
High
High
impedance
High
High
impedance
High
High
High
impedance
High
impedance
High
impedance
RE = V
High impedance
CC1
RO1
High
impedance
High
impedance
High
impedance
High
impedance
RE = floating
Active
Active
Active
High impedance
Active
RO2
Active
Active
Active
Active
High
impedance
High
impedance
High
impedance
High
impedance
ꢀriver outputs (Y, Z)
High impedance
Internal barrier
communication
Communication
attempted
Active
ꢀisabled
ꢀisabled
ꢀisabled
ꢀisabled
Low
(60µA pull-
down)
High
High
High
High
High
(100µA pullup)
(100µA pullup) (100µA pullup) (100µA pullup) (100µA pullup)
Fault indicator on RE
18 ______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
multidrop-network applications circuit. Figure 12 shows
the MAX3535E/MXL1535E functioning as line repeaters
Applications Information
Typical Applications
The MAX3535E/MXL1535E transceivers facilitate bi-
directional data communications on multipoint bus
transmission lines. Figure 11 shows a typical RS-485
with cable lengths longer than 4000ft. To minimize
reflections, terminate the line at both ends in its charac-
teristic impedance. Keep stub lengths off the main line
as short as possible.
B
DI
D
120Ω
A
DE
A
B
A
B
RO
R
R
R
RE
RE
RE
D
D
RO DE
DI
RO DE
DI
1/2
BAT54C
TGM-240
CONTROL GROUND
RS-485 GROUND
0.1µF
10µF
1/2
BAT54C
ST1
ST2
GND2
V
CC2
+3.3V
V
CC1
TRANSFORMER
DRIVER
VOLTAGE
REGULATOR
0.1µF
10µF
A
RO1
R
B
RECEIVER
RO2
RE
DE
DRIVER
Y
Z
120Ω
D
V
DI
CC2
SLO
MAX3535E
GND1
BARRIER
BARRIER
TRANSCEIVER
TRANSCEIVER
ISOLATION BARRIER
Figure 11. Typical Half-Duplex Multidrop RS-485 Network
______________________________________________________________________________________ 19
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
1/2
BAT54C
TGM-250
CONTROL GROUND
RS-422 GROUND
0.1µF
10µF
1/2
BAT54C
+5V
V
GND2
ST2
ST1
CC2
V
CC1
TRANSFORMER
DRIVER
10µF
0.1µF
VOLTAGE
REGULATOR
A
MAX488
Y
RO1
120Ω
D
R
D
B
DI
Z
RECEIVER
RE
DE
RO2
A
R
RO
DRIVER
Y
Z
B
R
120Ω
D
DI
V
CC2
GND1
MAX3535E
MXL1535E
BARRIER
TRANSCEIVER
BARRIER
TRANSCEIVER
SLO
ISOLATION BARRIER
Figure 12. Using the MAX3535E/MXL1535E as an RS-422 Line Repeater
Transformer Selection
The MXL1535E is a pin-for-pin compatible upgrade of
the LTC1535, making any transformer designed for that
device suitable for the MXL1535E (see Table 4). These
transformers all have a turns ratio of about 1:1.3CT.
TRANSFORMER DRIVER OUTPUT STAGE
V
CC1
The MAX3535E can operate with any of the transformers
listed in Table 4, in addition to smaller, thinner transform-
ers designed for the MAX845 and MAX253. The 420kHz
transformer driver operates with single primary and cen-
ter-tapped secondary transformers. When selecting a
transformer, do not exceed its ET product, the product of
the maximum primary voltage and half the highest period
of oscillation (lowest oscillating frequency). This ensures
that the transformer does not enter saturation. Calculate
the minimum ET product for the transformer primary as:
R
R
OH
OH
ST1
ST2
TRANSFORMER
PRIMARY
R
OL
R
OL
ET = V
/ (2 x f
)
MAX
MIN
GND1
where, V
is the worst-case maximum supply voltage,
is the minimum frequency at that supply voltage.
Using +5.5V and 290kHz gives a required minimum ET
MAX
and f
MIN
Figure 13. Transformer Driver Output Stage
20 ______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
product of 9.5V-µs. The commercially available trans-
less than 0.1in. To minimize power consumption, select
the turns ratio of the transformer to produce the minimum
formers for the MAX845 listed in Table 5 meet that
requirement. In most cases, use half of the center-tapped
primary winding with the MAX3535E and leave the other
end of the primary floating. Most of the transformers in
Table 5 are 1:1:1 or 1:1:1:1 turns ratio.
ꢀC voltage required at V
(+3.13V) under worst-case,
CC2
high-temperature, low-V
, and full-load conditions. For
CC1
light loads on the isolated side, ensure that the voltage at
does not exceed +7.5V. For example, the CTX01-
V
CC2
14659 transformer results in 85mA (typ) V
supply cur-
CC1
For +3.3V operation (+3.6V maximum) the required pri-
mary ET product is 6.2V-µs. All of the previously men-
tioned transformers meet this requirement. Table 6 lists
some other transformers with step-up turns ratios
specifically tailored for +3.3V operation. Most of the
transformers in Table 6 are 1:1:1.3:1.3.
rent with full load on the RS-485 driver. Using a TGM250
1:1:1 transformer lowers the V supply current to 65mA
CC1
(typ), while maintaining good margin on the V
supply.
CC2
A slight step-down transformer can result in extra power
savings in some situations. A custom wound sample
transformer with 23 primary turns and 20:20 secondary
turns on a Ferronics 11-050B core operates well with a
By using a HALO TGM-010 or Midcom 95061 trans-
former, it becomes possible to build a complete isolated
RS-485/RS-422 transceiver with a maximum thickness
V
CC1
supply current of 51mA (typ).
Table 4. Transformers for the MXL1535E/MAX3535E
MANUFACTURER
PART NUMBER
CTX01-14659
CTX01-14608
ISOLATION VOLTAGE (1s)
PHONE NUMBER
561-241-7876
Cooper Electronic Technologies, Inc.
Cooper Electronic Technologies, Inc.
500V
3750V
561-241-7876
RMS
EPCOS AG (Germany)
(USA)
0 89-626-2-80-00
800-888-7724
B78304-A1477-A3
500V
Midcom, Inc.
31160R
P1597
1250V
500V
100V
500V
605-886-4385
33-3-85-35-04-04
03-3667-3320
775-852-0145
Pulse FEE (France)
Sumida Corporation (Japan)
Transpower Technologies, Inc.
S-167-5779
TTI7780-SM
Table 5. Transformers for MAX3535E at +5V
PART
NUMBER
ISOLATION
VOLTAGE (1s)
PHONE
NUMBER
MANUFACTURER
WEBSITE
TGM-010
TGM-250
TGM-350
TGM-450
500V
RMS
2000V
3000V
4500V
RMS
RMS
RMS
HALO Electronics, Inc.
650-903-3800
952-894-9590
www.haloelectronics.com/6pin.html
www.bhelectronics.com/PꢀFs/ꢀC-
ꢀCConverterTransformers.pdf
BH Electronics, Inc.
Coilcraft, Inc.
500-1749
U6982-C
3750V
1500V
RMS
RMS
800-322-2645
44-1236-730595
www.coilcraft.com/minitrans.cfm
7825355
7625335
95061
1500V
Newport/C&ꢀ Technologies
520-295-4300
www.dc-dc.com/products/productline.asp?Eꢀ=9
4000V
1250V
Midcom, Inc.
605-886-4385
818-894-5791
714-898-0960
949-452-0511
www.midcom-inc.com
PCA Electronics, Inc.
Rhombus Industries, Inc.
Premier Magnetics, Inc.
EPC3115S-5
T-1110
700V ꢀC
www.pca.com/ꢀatasheets/EPC3117S-X.pdf
www.rhombus-ind.com/pt-cat/maxim.pdf
www.premiermag.com/pdf/pmsm15.pdf
1800V
RMS
RMS
PM-SM15
1500V
______________________________________________________________________________________ 21
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
Table 6. Transformers for MAX3535E at +3.3V
PART
NUMBER
ISOLATION
VOLTAGE (1s)
PHONE
NUMBER
MANUFACTURER
WEBSITE
TGM-040
TGM-240
TGM-340
TGM-340
500V
RMS
2000V
3000V
4500V
RMS
RMS
RMS
HALO Electronics, Inc.
650-903-3800
952-894-9590
www.haloelectronics.com/6pin.html
www.bhelectronics.com/PꢀFs/ꢀC-
ꢀCConverterTransformers.pdf
BH Electronics, Inc.
Coilcraft, Inc.
500-2582
Q4470-C
2000V
1500V
RMS
RMS
800-322-2645
44-1236-730595
www.coilcraft.com/minitrans.cfm
www.dc-dc.com/products/productline.asp?Eꢀ=9
www.midcom-inc.com
78253335
76253335
95062
1500V
Newport/C&ꢀ Technologies
Midcom, Inc.
520-295-4300
605-886-4385
4000V
1250V
95063
1250V
PCA Electronics, Inc.
EPC3115S-2
T-1107
700V ꢀC
818-894-5791
714-898-0960
www.pca.com/ꢀatasheets/EPC3117S-X.pdf
www.rhombus-ind.com/pt-cat/maxim.pdf
Rhombus Industries, Inc.
1800V
RMS
Premier Magnetics Inc.
PM-SM16
1500V
949-452-0511
www.premiermag.com/pdf/pmsm15.pdf
RMS
15ꢀV ESD ꢁrotection
As with all Maxim devices, ESꢀ-protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assembly. The driver outputs and receiver inputs have
extra protection against static electricity. Maxim’s engi-
neers have developed state-of-the-art structures to pro-
tect these pins against ESꢀ of 15kV without damage.
The ESꢀ structures withstand high ESꢀ in all states.
After an ESꢀ event, the MAX3535E/MXL1535E keep
working without latchup. ESꢀ protection can be tested
in various ways. The transmitter outputs and receiver
inputs of this product family are characterized for pro-
tection to 15kV using the Human Body Model.
R
1MΩ
R 1500Ω
D
C
DISCHARGE
RESISTANCE
CHARGE-CURRENT-
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
C
STORAGE
CAPACITOR
s
100pF
SOURCE
ESD Test Conditions
The 15kV ESꢀ test specifications apply only to the A,
B, Y, and Z I/O pins. The test surge is referenced to
GNꢀ2. All remaining pins are 2kV ESꢀ protected.
Figure 14. Human Body ESD Test Model
charged into low impedance. This model consists of a
100pF capacitor charged to the ESꢀ voltage of interest,
which is then discharged into the test device through a
1.5kΩ resistor.
Human Body Model
Figure 14 shows the Human Body Model, and Figure
15 shows the current waveform it generates when dis-
22 ______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
DATA SKEW vs. DATA RATE
50
45
I 100%
P
90%
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
r
40
35
30
25
20
15
10
5
AMPERES
36.8%
10%
0
TYP SKEW
MAX SKEW
TIME
0
t
RL
t
DL
0
CURRENT WAVEFORM
0
250 500 750 1000 1250 1500 1750 2000
DATA RATE (kbps)
Figure 15. Human Body Current Waveform
Figure 16. Data Skew vs. Data Rate Graph
Machine Model
Higher rates are possible but with more distortion and
jitter. The data rate should always be limited below
1.75Mbps for both receiver and driver to avoid interfer-
ence with the internal barrier communication.
The Machine Model for ESꢀ tests all pins using a
200pF storage capacitor and zero discharge resis-
tance. Its objective is to simulate the stress caused by
contact that occurs with handling and assembly during
manufacturing. All pins require this protection during
manufacturing, not just inputs and outputs. Therefore,
after PC board assembly, the Machine Model is less
relevant to I/O ports.
Layout Considerations
The MAX3535E/MXL1535E pin configurations enable
optimal PC board layout by minimizing interconnection
lengths and crossovers:
• For maximum isolation, the isolation barrier should not
be breached except by the MAX3535E/MXL1535E and
the transformer. Connections and components from
one side of the barrier should not be located near those
of the other side of barrier.
Sꢀew
The self-oscillation circuit shown in Figure 5 is an excel-
lent way to get an approximate measure of the speed
of the MAX3535E/MXL1535E. An oscillation frequency
of 250kHz in this configuration implies a data rate of at
least 500kbps for the receiver and transmitter com-
bined. In practice, data can usually be sent and
received at a considerably higher data rate, normally
limited by the allowable jitter and data skew. If the sys-
tem can tolerate a 25% data skew, (the difference
• A shield trace connected to the ground on each side of
the barrier can help intercept capacitive currents that
might otherwise couple into the ꢀI and SOL inputs. In a
double-sided or multilayer board, these shield traces
should be present on all conductor layers.
between t
and t
), the 285ns maximum jitter
PHL1
• Try to maximize the width of the isolation barrier
wherever possible. A clear space of at least 0.25in
between GNꢀ1 and GNꢀ2 is recommended.
PLH1
specification implies a data rate of 877kbps. Lower
data rates result in less distortion and jitter (Figure 16).
______________________________________________________________________________________ 23
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
Typical Application Circuit
TGM-240
1/2
BAT54C
CONTROL GROUND
RS-485 GROUND
0.1µF
10µF
1/2
BAT54C
ST1
ST2
TRANSFORMER
GND2
V
CC2
+3.3V
V
CC1
DRIVER
VOLTAGE
REGULATOR
0.1µF
10µF
A
RO1
B
µC
RECEIVER
RO2
RE
DE
DRIVER
Y
Z
DI
V
CC2
MAX3535E
GND1
BARRIER
TRANSCEIVER
BARRIER
TRANSCEIVER
SLO
ISOLATION BARRIER
Chip Information
PROCESS: BiCMOS
TRANSISTOR COUNT: 7379
24 ______________________________________________________________________________________
+3V to +5V, 2500V
Isolated RS-485/RS-422
RMS
Transceivers with 15ꢀV ESD ꢁrotection
ꢁacꢀage 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.)
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.
Maxim Integrated ꢁroducts, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 25
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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