Datasheet

MAX1480E/MAX1490E
±15kV ESD-Protected, Isolated RS-485/RS-422
Data Interfaces
8 _______________________________________________________________________________________
________________________________________________________________Pin Description
MAX1490EA/
MAX1490EB
MAX1480EA/
MAX1480EC
ISO RO LED
ISO COM2
ISO COM120 16
Isolated Common. For MAX1480EA/MAX1480EC, connect to ISO COM2 (pin
16) (Figures 1 and 2).
15 13
Isolated Receiver Output LED. Internal LED anode in MAX1480EA/MAX1480EC and
LED cathode in MAX1490EA/MAX1490EB. Connect to ISO RO DRV through a resis-
tor (Table 1 for MAX1480EA/MAX1480EC; Table 2 for MAX1490EA/MAX1490EB).
16 — Isolated Common. Connect to ISO COM1 (pin 20).
ISO DE DRV
ISO V
CC2
ISO DI DRV
17 —
Isolated Driver-Enable Drive. The driver outputs, A and B, are enabled by bringing
DE
´ high. The driver outputs are high impedance when DE´ is low. If the driver
outputs are enabled, the device functions as a line driver. While the driver outputs
are high impedance, the device functions as a line receiver. Open-collector out-
put; must have pullup to ISO VCC_ and be connected to ISO DE IN for normal
operation (Table 1).
18 14
Isolated Supply Voltage. Connect to ISO V
CC1
(pin 26 for MAX1480EA/
MAX1480EC, or pin 22 for MAX1490EA/MAX1490EB).
19 15
Isolated Driver-Input Drive. With DE´ high (MAX1480EA/MAX1480EC only), a low on
DI
´ forces output A low and output B high. Similarly, a high on DI´ forces output A
high and output B low. Connect to ISO DI IN (on the MAX1480EA/MAX1480EC only)
for normal operation. Open-collector output; connect a pullup resistor to ISO V
CC_
(Table 1 for MAX1480EA/MAX1480EC, Table 2 for MAX1490EA/MAX1490EB).
DI
DE
RO
9 9
Driver Input. With DE´ high (MAX1480EA/MAX1480EC only), a low on DI´ forces
output A low and output B high. Similarly, a high on DI
´ forces output A high and
output B low. Drives internal LED cathode through a resistor (see Table 1 for
MAX1480EA/MAX1480EC, Table 2 for MAX1490EA/MAX1490EB).
11 —
Driver-Enable Input. The driver outputs, A and B, are enabled by bringing DE´
high. The driver outputs are high impedance when DE´ is low. If the driver out-
puts are enabled, the device functions as a line driver. While the driver outputs
are high impedance, the device functions as a line receiver. Drives internal
LED cathode through a resistor (Table 1).
— 11
Receiver Output. If A > B by 200mV, RO is high; if A < B by 200mV, RO is low.
Open collector; must have pullup to V
CC
(Table 2).
GND2
V
CC5
12 12 Logic-Side Ground. Connect to GND1 (pin 5).
14 — Logic-Side (Nonisolated Side) +5V Supply Voltage
GND1
FS
SD
5 5 Logic-Side Ground. Connect to GND2 (pin 12).
6 6
Frequency Select Input. If FS = V
CC_
or is open, switch frequency is high; if FS
= GND, switch frequency is low. For optimal performance and minimal supply
current, connect FS to V
CC_
or leave unconnected.
7 7
Shutdown Input. Ground for normal operation. When high, the power oscillator is
disabled.
NAME
V
CC1
–V
CC4
D1, D2
PIN
FUNCTION
1, 2, 8, 10 1, 2, 8, 10 Logic-Side (Nonisolated Side) +5V Supply Voltages
3, 4 3, 4 Internal Connections. Leave these pins unconnected.
RO
13 —
Receiver Output. If A > B by 200mV, RO is low; if A < B by 200mV, RO is high.
Open collector; must have pullup to V
CC
(Table 1).