STC485E Datasheet, PDF (6/11 Pages) List of Unclassifed Manufacturers – ±15kV ESD-Protected,Slew-Rate-Limited, Fail-Safe,True RS-485 Transceivers

Pin Description
PIN
NAME
FUNCTION
1
RO
Receiver Output. If A > B by -50mV, RO will be high; if A < B by 200mV, RO will be low.
2
Receiver Output Enable. RO is enabled when /RE is low; RO is high impedance when /RE is high. If
/RE
/RE is high and DE is low, the device will enter a low-power shutdown mode.
Driver Output Enable. The driver outputs are enabled by bringing DE high. They are high impedance
3
when DE is low. If /RE is high and DE is low, the device will enter a low-power shutdown mode. If the
DE
driver outputs are enabled, the parts function as line drivers. While they are high impedance, they
function as line receivers if /RE is low.
4
Driver Input. A low on DI forces output A low and output B high. Similarly, a high on DI forces output
DI
A high and output B low.
5
GND Ground
6
A
Noninverting Receiver Input and Noninverting Driver Output
7
B
Inverting Receiver Input and Inverting Driver Output
8
VCC Positive Supply: VCC=5V±5%
Function Tables
Table 1. Transmitting
INPUTS
/RE DE DI
X11
X10
00X
10X
OUTPUTS
B
A
0
1
1
0
High-Z High-Z
High-Z High-Z
X = Don’t care; High-Z = High impedance
MODE
Normal
Normal
Normal
Shutdown
Table 2. Receiving
INPUTS
OUTPUTS
/RE DE
A, B
0
X
=?-0.05V
0
X
=?-0.2V
0 X Inputs Open
10
X
RO
1
0
1
High-Z
X = Don’t care; High-Z = High impedance
MODE
Normal
Normal
Normal
Shutdown
Figure 1. STC485E / Pin Configuration and Typical Operating Circuit