DS481_14 Datasheet, PDF (2/17 Pages) Texas Instruments – Low Power RS-485/RS-422 Multipoint Transceiver with Sleep Mode

DS481
SNLS131B – JULY 2000 – REVISED MARCH 2013
www.ti.com
Pin Name
RO
RE ⁽¹⁾
Number
1
2
DE
3
DI
4
GND
5
DO/RI
6
DO ⁽¹⁾
/RI ⁽¹⁾
7
V_CC
8
(1) Non Terminated, Open Input only
Table 1. Pin Descriptions
DESCRIPTION
Receiver Output: When RE (Receiver Enable) is LOW, the receiver is enabled (ON), if DO/RI
≥ DO ⁽¹⁾/RI ⁽¹⁾ by 200 mV, RO will be HIGH. If DO/RI ≤ DO ⁽¹⁾/RI ⁽¹⁾ by 200 mV, RO will be
LOW. Additionally RO will be HIGH for OPEN (Non-terminated) Inputs.
Receiver Output Enable: When RE ⁽¹⁾ is LOW the receiver output is enabled. When RE ⁽¹⁾ is
HIGH, the receiver output is in TRI-STATE (OFF). When RE ⁽¹⁾ is HIGH and DE is LOW, the
device will enter a low-current sleep mode after 600 ns.
Driver Output Enable: When DE is HIGH, the driver outputs are enabled. When DE is LOW,
the driver outputs are in TRI-STATE (OFF). When RE ⁽¹⁾ is HIGH and DE is LOW, the device
will enter a low-current sleep mode after 600 ns.
Driver Input: When DE (Driver Enable) is HIGH, the driver is enabled, if DI is LOW, then
DO/RI will be LOW and DO ⁽¹⁾/RI ⁽¹⁾ will be HIGH. If DI is HIGH, then DO/RI is HIGH and
DO ⁽¹⁾/RI ⁽¹⁾ is LOW.
Ground Connection.
Driver Output/Receiver Input, 485 Bus Pin.
Driver Output/Receiver Input, 485 Bus Pin.
Positive Power Supply Connection: Recommended operating range for V_CC is +4.75V to
+5.25V.
Truth Table
DRIVER SECTION
RE ⁽¹⁾
DE
X ⁽²⁾
H
X ⁽²⁾
H
X ⁽²⁾
L
RECEIVER SECTION
RE ⁽¹⁾
DE
L
L
L
L
H
X ⁽²⁾
L
L
DI
A
H
H
L
L
X ⁽²⁾
Z ⁽²⁾
A-B
≥+0.2V
≤−0.2V
X ⁽²⁾
OPEN ⁽¹⁾
B
L
H
Z^{(2) (3)}
RO
H
L
Z ^{(2) (3)}
H
(1) Non Terminated, Open Input only
(2) X = indeterminate
Z = TRI-STATE
(3) Device enters sleep mode if enable conditions are held > 600 ns, DE = L and RE = H. RE is Non Terminated and Open Input only.
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
2
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