IL600 Series Isolators

13

NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617

(952) 829-9217

www.nve.com

YouTube.com/NveCorporation

iso-apps@nve.com

Illustrative Applications

Isolated RS-485 and RS-422 Receivers Using IL610s

Number of

Nodes

Current Limit

Resistors (Ω

Ω

Ω

Ω

)

1

None

2

17

3

22

4

27

5

27

6

27

7

30

8

33

IL610 components can be used as simple isolated RS-485 or RS-422 receivers, terminating

signals at the IL610 for a fraction of the cost of an isolated node. Cabling is simplified by

eliminating the need to power the input side of the receiving board. No current-limiting

resistor is needed for a single receiver because it will draw less current than the driver

maximum. Current limiting resistors allow at least eight nodes without exceeding the

maximum load of the transceiver. Placement of the current-limiting resistors on both lines

provides better dynamic signal balance. There is generally no need for line termination

resistors below data rates of approximately 10 Mbps because the IL610 coil resistance of

approximately 85 Ω is close to the characteristic impedance of most cables. The circuit is

intrinsically open-circuit failsafe because the IL610 is guaranteed to switch to the high state

when the coil input current is less than 0.5 mA.

GND

2

V

DD

B

ISL8485

D

47nF

V

DD1

GND

1

3

2

5

6

7

8

4

5

7

2

1

-

+

IL610

R

RE

A

8

6

1

R

47nF