MAX13487E Datasheet, PDF (11/17 Pages) Maxim Integrated Products – Half-Duplex RS-485-/RS-422-Compatible Transceiver with AutoDirection Control

Half-Duplex RS-485-/RS-422-Compatible
Transceiver with AutoDirection Control
Pin Description
PIN
NAME
FUNCTION
1
RO
Receiver Output. When receiver is enabled and V(A) - V(B) > +200mV, RO is high. If V(A) - V(B)
< -200mV, RO is low.
2
RE
Receiver Output Enable. Drive RE low to enable the RO. Drive RE high to let the AutoDirection circuit
control the receiver. RE is a hot-swap input (see the Hot-Swap Capability section for more details).
3
SHDN
Shutdown. Drive SHDN high to let the device operate in normal operation. Drive SHDN low to put the part
in shutdown.
Driver Input. Drive DI low to force noninverting output low and inverting output high. Drive DI high to force
4
DI
noninverting output high and inverting output low. DI is an input to the internal state machine that
automatically enables and disables the driver. See the Function Tables and General Description for more
information. DI is a hot-swap input (see the Hot-Swap Capability section for more details).
5
GND
Ground
6
A
Noninverting Receiver Input and Noninverting Driver Output
7
B
Inverting Receiver Input and Inverting Driver Output
8
V_CC
Positive Supply, V_CC = +5V ±5%. Bypass V_CC to GND with a 0.1µF capacitor.
SHDN
1
1
1
1
0
Function Tables
TRANSMITTING
INPUTS
OUTPUTS
DI
A-B > V_DT
ACTION
A
B
0
X
Turn driver ON
0
1
1
False
If driver was OFF, keep it OFF
HIGH IMPEDANCE
HIGH IMPEDANCE
1
False
If driver was ON, keep it ON
1
0
1
True
Turn driver OFF
HIGH IMPEDANCE
HIGH IMPEDANCE
X
X
X
SHUTDOWN
RECEIVING
SHDN
1
INPUTS
RE
A-B
DRIVER STATE
0
≥+200mV
X
RECEIVER STATE
ON
1
0
≤-200mV
X
ON
1
1
X
ON
OFF
1
1
>+200mV
OFF
ON
1
1
≤-200mV
OFF
ON
0
X
X
X
X
X = Don’t care, shutdown mode, driver, and receiver outputs are in high impedance.
OUTPUT
RO
1
0
HIGH IMPEDANCE
1
0
SHUTDOWN
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