SP485EN-L Datasheet, PDF (7/11 Pages) Exar Corporation – Low Power Half-Duplex RS-485 Transceivers

INPUTS
OUTPUTS
LINE
RE DE DI CONDITION A B
X
1
1
No Fault
1
0
X
1
0
No Fault
0
1
X
0
X
X
ZZ
X
1
X
Fault
ZZ
Table 1. Transmit Function Truth Table
Function Truth Tables
INPUTS
RE DE
00
00
00
10
A-B
+0.2V
-0.2V
Inputs Open
X
OUTPUTS
R
1
0
1
Z
Table 2. Receive Function Truth Table
SWITCHING WAVEFORMS
fSP485 = 1MHz; fSP483 = 100kHz; t_R ≤10ns; t_F ≤10ns
+3V
DE
0V
5V
A, B
V_OL
1.5V
t _ZL
2.3V
Output normally LOW
1.5V
t _LZ
0.5V
V_OH
A, B
0V
2.3V
t _ZH
Output normally HIGH
0.5V
t _HZ
Figure 6. Driver Enable and Disable Times
V_OD2⁺
A– B
V_OD2^–
0V
INPUT
0V
V_OH
R
V_OL
t_PHL
1.5V
OUTPUT
t_PLH
1.5V
t _SKEW = |t _PLH - t_PHL |
fSP485 = 1MHz; fSP483 = 100kHz; t_R ≤10ns; t_F ≤10ns
Figure 7. Receiver Propagation Delays
+3V
RE
0V
5V
R
V_IL
V_IH
R
0V
fSP485 = 1MHz; fSP483 = 100kHz; t_R ≤10ns; t_F ≤10ns
1.5V
t _ZL
1.5V
Output normally LOW
1.5V
t _LZ
0.5V
1.5V
t _ZH
Output normally HIGH
0.5V
t _HZ
Figure 8. Receiver Enable and Disable Times
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com

SP483_SP485_100_071410