IL610A NVE Corp., IL610A Datasheet - Page 11

• Manufacturer Part Number: IL610A
• Description: Passive-input Digital Isolators ? Open Drain Outputs
• Manufacturer: NVE Corp.

Illustrative Applications
Isolated RS-485 and RS-422 Receivers
Using IL610As
IL610As can be used as simple isolated
RS-485 or RS-422 receivers, terminating
signals at the IL610A for a fraction of the
cost of an isolated node. Cabling is greatly
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 chip. Placement of the current-limiting resistors on both lines provides
better dynamic signal balance. There is no need for line termination resistors
because the IL610A coil resistance of approximately 85 Ω is close to the
characteristic impedance of most cables. The circuit is intrinsically open circuit
failsafe because the IL610A is guaranteed to switch to the high state when the
coil input current is less than 500 µA. For higher speed, a faster output device
(such the CMOS-output IL600-Series Isolators) are needed as well as possibly
better impedance matching.
V
R
D
DD1
C
1
8
1
4
5
GND
ISL8485
1
1
7
6
B/Z
A/Y
Notes:
All other capacitors are 47 nF ceramic
C
boost
is application specific
C
boost
3
3
2
+
IL610A
-
Number of
Nodes
1
2
3
4
5
6
7
8
11
Current Limit
Resistors (Ω)
GND
None
8
7
6
5
17
22
27
27
27
30
30
C
2
2
2
2
R
V
DD2
IL600A Series