ADM485 half-duplex RS-485 transceiver pinout

The ADM485 connects logic-level data to one shared differential pair. Independent driver and receiver enable inputs control bus ownership.

MSOP-8 (RM-8)

8 contacts Current package

Analog Devices · Mini small-outline package.

Top view. Locate the package index before counting counterclockwise from pin 1.

Input · Data

Driver data input. A is higher than B for a driven logic one.

Analog Devices ADM485 Rev. F, Table 6

Pin	Signal	Direction	Function
1	RO Output	Output	Receiver data. Drives high when enabled and A exceeds B by at least 200 mV.
2	/RE Input	Input	Active-low receiver output enable. RO goes high impedance when this pin is high.
3	DE Input	Input	Active-high driver enable. With DE low the bus outputs go high impedance.
4	DI Input	Input	Driver data input. A is higher than B for a driven logic one.
5	GND Return	Return	Supply and bus voltage reference.
6	A Bidirectional	Bidirectional	Noninverting side of the differential pair.
7	B Bidirectional	Bidirectional	Inverting side of the differential pair.
8	VCC Supply	Supply	5 V supply, within ±5%.

Tie /RE and DE together when the controller should receive while idle and drive only while sending.

Match the peer by polarity and connect a reference conductor where required by the installation. Terminate at the physical ends of the trunk.

Parameter	Limit	Conditions and source
Supply4.75–5.25 V	4.75–5.25 V	Recommended operating supply. Analog Devices ADM485 Rev. F, Table 1
Logic input thresholds0.8 V max low · 2.0 V min high	0.8 V max low · 2.0 V min high	DI, DE and /RE. RO can drive above 3.3 V. Analog Devices ADM485 Rev. F, Table 1
Receiver differential threshold−200 mV to +200 mV	−200 mV to +200 mV	Common-mode range −7 V to +12 V. Analog Devices ADM485 Rev. F, Table 1

The eight contact assignments are shared by three packages with different mechanical drawings.

Analog Devices ADM485 Rev. F· Electrical and timing limits, pin map, wiring and ordering guide.
Source register· Document revisions, applicable order codes, consulted sections and available file checksums.