M
High CMRR RS-485 Transceiver
with ±50V Isolation
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
All voltages referenced to GND unless otherwise noted.
Supply Voltage (V
CC
).............................................................+7V
Cable Ground (ISOCOM) ....................................................±75V
Isolated Supply ISOVCC Relative to Cable Ground
(ISOCOM)............................................................................+7V
Digital Input, Output Voltage
(DI, DE,
RE
, TXP, RXP, RO)......................-0.3V to (V
CC
+ 0.3V)
Digital Inputs (H/
F
) Relative to Cable Ground
(ISOCOM)..........................................-0.3V to (ISOVCC + 0.3V)
Driver Output Voltage (Y, Z), Relative to Cable Ground
(ISOCOM).............................................................-8V to +12.5V
Receiver Input Voltage (A, B), Relative to Cable Ground
(ISOCOM).............................................................-8V to +12.5V
Termination Connections (YR, ZR, AR, BR) Relative to Cable
Ground (ISOCOM)................................................-8V to +12.5V
ELECTRICAL CHARACTERISTICS
(V
CC
= +5V ±5%, YR = ZR = AR = BR = ISOCOM, C1 = C2 = 0.047μF, C3 = C4 = 1μF, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at V
CC
= +5V and T
A
= +25°C.) (Note 1)
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.
Charge-Pump Capacitance Low
(C1LO, C2LO) .......................................-0.3V to (V
CC
+ 0.3V)
Charge-Pump Capacitance High (C1HI, C2HI) Relative
to Cable Ground (ISOCOM)...........-0.3V to (ISOVCC + 0.3V)
Continuous Power Dissipation
28-Pin SSOP (derate 10.8mW/°C above +70°C) ........860mW
28-Pin PDIP (derate 14.3mW/°C above +70°C)........1143mW
Operating Temperature Ranges
MAX3157C_I .....................................................0°C to +70°C
MAX3157E_I ..................................................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range ............................-65°C to +160°C
Lead Temperature (soldering, 10s) ................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DRIVER
Differential Driver Output,
No Load
V
OD1
Figure 1, R = 10M
6
V
Figure 1, R = 50
(RS-422)
Figure 1, R = 27
(RS-485)
2.0
1.5
Differential Driver Output,
Loaded
V
OD2
V
Change in Magnitude of
Differential Output Voltage
(Note 2)
V
OD
Figure 1, R = 50
or R = 27
0.2
V
Driver Common-Mode Voltage
V
OC
Figure 1, R = 50
or R = 27
,
V
OC
relative to ISOCOM
3.5
V
Change in Magnitude of
Common-Mode Voltage
(Note 2)
V
OC
Figure 1, R = 50
or R = 27
0.2
V
Input High Voltage
V
IH
DE, DI,
RE
, TXP, RXP, relative to GND,
H/
F
relative to ISOCOM
2.0
V
Input Low Voltage
V
IL
DE, DI,
RE
, TXP, RXP, relative to GND,
H/
F
relative to ISOCOM
0.8
V
DI Input Hysteresis
V
HYS
I
IN1
I
IN2
100
mV
DE, DI,
RE
H/
F
, TXP, RXP internal pulldown
±2
40
Input Current
10
μA
DE = GND, V
CC
= GND or 5.25V, -7V
≤
(V
IN
-
V
ISOCOM
)
≤
12V, AR = BR = ISOCOM
-5.0
8.0
Input Current (A and B)
I
IN3
DE = GND, V
CC
= GND or 5.25V, -7V
≤
(V
IN
-
V
ISOCOM
)
≤
12V, AR open, BR open
-0.58
1.0
mA