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Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
_______________________________________________________Switching Waveforms
DI
3V
0V
Z
Y
VO
0V
-VO
VO
1.5V
tPLH
1/2 VO
10%
tR
90%
90%
tPHL
1.5V
1/2 VO
10%
tF
VDIFF = V (Y) - V (Z)
VDIFF
tSKEW = | tPLH - tPHL |
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0V
Y, Z
VOL
Y, Z
0V
1.5V
1.5V
VOL +0.5V
VOH -0.5V
2.3V
2.3V
tZL(SHDN), tZL
tLZ
tZH(SHDN), tZH
tHZ
DE
VOH
VOL
VID
-VID
1.5V
0V
1.5V
OUTPUT
INPUT
0V
RO
A-B
tPLH
tPHL
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0V
VCC
RO
RO
0V
1.5V
1.5V
VOL + 0.5V
VOH - 0.5V
1.5V
1.5V
tZL(SHDN), tZL
tLZ
tZH(SHDN), tZH
tHZ
RE
_________________Function Tables (HWD481/HWD483/HWD485/HWD487/HWD1487)
Figure 8. Driver Propagation Delays
Figure 9. Driver Enable and Disable Times (except HWD488 and
HWD490)
Figure 10. Receiver Propagation Delays
Figure 11. Receiver Enable and Disable Times (except HWD488
and HWD490)
Table 1. Transmitting
Table 2. Receiving
INPUTS
OUTPUT
RE
DE
A-B
RO
0
0
0
1
0
0
0
0
> +0.2V
< -0.2V
Inputs open
X
1
0
1
High-Z
*
X = Don't care
High-Z = High impedance
* Shutdown mode for HWD481/HWD483/HWD487
INPUTS
OUTPUTS
RE
DE
DI
Z
Y
X
X
0
1
1
1
0
0
1
0
X
X
0
1
High-Z
High-Z
*
1
0
High-Z
High-Z
*
X = Don't care
High-Z = High impedance
* Shutdown mode for HWD481/HWD483/HWD487
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