6

®

ISO150

T

ISOLATION BARRIER

Data is transmitted by coupling complementary logic pulses

to the receiver through two 0.4pF capacitors. These capaci-

tors are built into the ISO150 package with Faraday shield-

ing to guard against false triggering by external electrostatic

fields.

The integrity of the isolation barrier of the ISO150 is

verified by partial discharge testing. 2400Vrms, 60Hz, is

applied across the barrier for one second while measuring

any tiny discharge currents that may flow through the

barrier. These current pulses are produced by localized

ionization within the barrier. This is the most sensitive and

reliable indicator of barrier integrity and longevity, and does

not damage the barrier. A device fails the test if five or more

current pulses of 5pC or greater are detected.

FIGURE 1. Basic Operation Diagram.

Conventional isolation barrier testing applies test voltage far

in excess of the rated voltage to catastrophically break down

a marginal device. A device that passes the test may be

weakened, and lead to premature failure.

APPLICATIONS INFORMATION

Figure 1 shows the ISO150 connected for basic operation.

Channel 1 is configured to transmit data from side B to A.

Channel 2 is set for transmission from side A to B. The R/T pins

for each of the four transceivers are shown connected to the

required logic level for the transmission direction shown. The

transmission direction can be controlled by logic signals

applied to the R/T pins. Channel 1 and 2 can be independently

controlled for the desired transmission direction.

TYPICAL INSULATION RESISTANCE vs TEMPERATURE

0

20

40

60

80

100

120

140

160

180

Temperature (°C)

NOTES: (1) Power Supplies and grounds on

side A and side B are isolated. (2) Recommended

bypass: 0.1

µF in parallel with 1nF.

Data In

(1)

(1)

(2)

(1)

(1)

(2)

Channel 2

Data Out

Channel 1

Data Out

Channel 2

Data In

Channel 1

(Transmit)

(Transmit)

(Receive)

(Receive)

Channel 2

Channel 1

Side A

Side B