MAX1480E Datasheet, PDF (8/19 Pages) Maxim Integrated Products – 15kV ESD-Protected, Isolated RS-485/RS-422

±15kV ESD-Protected, Isolated RS-485/RS-422
Data Interfaces
________________________________________________________________Pin Description
PIN
MAX1480EA/ MAX1490EA/
MAX1480EC MAX1490EB
NAME
FUNCTION
1, 2, 8, 10
3, 4
5
6
7
9
11
—
12
13
14
1, 2, 8, 10
3, 4
5
6
7
9
—
11
12
—
—
V_CC1–V_CC4
D1, D2
GND1
FS
SD
DI
DE
RO
GND2
RO
V_CC5
Logic-Side (Nonisolated Side) +5V Supply Voltages
Internal Connections. Leave these pins unconnected.
Logic-Side Ground. Connect to GND2 (pin 12).
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.
Shutdown Input. Ground for normal operation. When high, the power oscillator is
disabled.
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).
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).
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).
Logic-Side Ground. Connect to GND1 (pin 5).
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).
Logic-Side (Nonisolated Side) +5V Supply Voltage
Isolated Receiver Output LED. Internal LED anode in MAX1480EA/MAX1480EC and
15
13
ISO RO LED 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
—
ISO COM2 Isolated Common. Connect to ISO COM1 (pin 20).
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
17
—
ISO DE DRV
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
ISO V_CC2
Isolated Supply Voltage. Connect to ISO V_CC1 (pin 26 for MAX1480EA/
MAX1480EC, or pin 22 for MAX1490EA/MAX1490EB).
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
19
15
ISO DI DRV 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).
20
16
ISO COM1
Isolated Common. For MAX1480EA/MAX1480EC, connect to ISO COM2 (pin
16) (Figures 1 and 2).
8 _______________________________________________________________________________________