UM3352E_15 Datasheet, PDF (6/13 Pages) Union Semiconductor, Inc. – ESD-Protected, Slew-Rate-Limited, Fail-Safe, True RS-485 Transceivers

Typical Operating Characteristics (Continued)
(V_CC=+5.0V, T_A=+25 C, unless otherwise noted.)
Transmitter Propagation Delay
RL=54Ω, CL=100pF
UM3352E
Receiver Propagation Delay
RL=54Ω, CL=100pF
DI
2V/div
A-B
2V/div
400ns/div
A-B
2V/div
RO
2V/div
400ns/div
Pin Description
Pin Number
1
2
3
4
5
6
7
8
Symbol
RO
______
RE
DE
DI
GND
A
B
V_CC
Function
Receiver Output. If (A-B)≥-50mV, RO will be high; if
(A-B)≤-200mV, RO will be low.
______
Receiver Output Enable_{__}._{___}D_{_} rive RE low to_{___}e_{__}n_{_} able Receiver, RO is
high impedance when RE is high. Drive RE high and DE low to
enter low-power shutdown mode.
Driver Enable. Drive DE high to enab_{_}l_{__}e_{___}drivers. The outputs are high
impedance when DE is low. Drive RE high and DE low to enter
low-power shutdown mode.
Driver Input. 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.
Ground
Non-Inverting Receiver Input and Non-Inverting Driver Output
Inverting Receiver Input and Inverting Driver Output
Power Supply for RS-485 Transceiver
RS-485 Communication Function Table
Table1. Transmitting
______
INPUTS
RE
DE
DI
X
1
1
X
1
0
0
0
X
1
0
X
X=Don’t care; High-Z=High impedance
OUTPUTS
B
A
0
1
1
0
High-Z
High-Z
Shutdown
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http://www.union-ic.com Rev.07 Sep.2015
6/13