5–1

FEATURES

• Couples AC and DC signals

• 0.01% Servo Linearity

• Wide Bandwidth, >200 KHz

• High Gain Stability,

±0.005%/C

• Low Input-Output Capacitance

• Low Power Consumption, < 15mw

1 sec.

• Internal Insulation Distance, >0.4

mm

for VDE

• Underwriters Lab File #E52744

• VDE Approval #0884 (Optional with

Option 1, Add -X001 Suffix)

• IL300G Replaced by IL300-X006

APPLICATIONS

• Power Supply Feedback Voltage/

Current

• Medical Sensor Isolation

• Audio Signal Interfacing

• Isolate Process Control Transducers

• Digital Telephone Isolation

DESCRIPTION

The IL300 Linear Optocoupler consists of

an AlGaAs IRLED irradiating an isolated

feedback and an output PIN photodiode

in a bifurcated arrangement. The feed-

back photodiode captures a percentage

of the LED's flux and generates a control

LED drive current. This technique com-

pensates for the LED's non-linear, time,

and temperature characteristics. The out-

put PIN photodiode produces an output

servo optical flux created by the LED.

The time and temperature stability of the

input-output coupler gain (K3) is insured

by using matched PIN photodiodes that

accurately track the output flux of the

LED.

A typical application circuit (Figure 1)

uses an operational amplifier at the circuit

input to drive the LED. The feedback

photodiode sources current to R1 con-

nected to the inverting input of U1. The

photocurrent, IP1, will be of a magnitude

DESCRIPTION (continued)

The magnitude of this current is directly proportional to the feedback transfer gain

rent to force sufficient photocurrent to keep the node voltage (Vb) equal to Va

The output photodiode is connected to a non-inverting voltage follower amplifier. The

photodiode load resistor, R2, performs the current to voltage conversion. The output

amplifier voltage is the product of the output forward gain (K2) times the LED current

output forward gain (K2) times the photodiode load resistor (R2) to the product of the

(K2 • R2)/(K1 • R1). The overall transfer gain is completely independent of the LED

forward current. The IL300 transfer gain (K3) is expressed as the ratio of the ouput

gain (K2) to the feedback gain (K1). This shows that the circuit gain becomes the

Figure 1. Typical application circuit

Dimensions in inches (mm)

1

2

3

4

8

7

6

5

K2

K1

Pin One I.D.

.268 (6.81)

.255 (6.48)

3

4

6

5

.390 (9.91)

.379 (9.63)

.045 (1.14)

.030 (.76)

4

° Typ.

.100 (2.54) Typ.

10

° Typ.

3

°–9°

.305 Typ.

(7.75) Typ.

.022 (.56)

.018 (.46)

.012 (.30)

.008 (.20)

.135 (3.43)

.115 (2.92)

1

2

8

7

.150 (3.81)

.130 (3.30)

.040 (1.02)

.030 (.76 )

8

7

6

5

K1

V

CC

V

CC

1

2

3

4

K2

V

CC

R1

Vc

R2

IL300

Vb

Va

+

-

U1

Vin

lp 1

V

CC

-

U2

+

lp 2

Vout

+

IF

IL300

LINEAR OPTOCOUPLER