4

UC19432

UC29432

UC39432

UC39432B

OVERVOLTAGE COMPARATOR APPLICATION

input voltage is less than 5.5V, the output is equal to the

is reversed biased which keeps the EA+ pin at 1.3V.

output is driven low. This forward biases the diode and

creates hysteresis by changing the threshold to 4.5V.

OPTOCOUPLER APPLICATION

The optocoupler application shown takes advantage of

the accessible pins REF and ISET. The ISET pin has a

33 ohm resistor to ground that protects the opto-coupler

by limiting the current to about 16mA. This also lowers

the transconductance to approximately 19mS. The ability

to adjust the transconductance gives the designer further

control of the loop gain. The REF pin is available to sat-

isfy any high precision voltage requirements.

Figure 2. 5.5V Overvoltage comparator with hysteresis.

UDG-95096

UDG-95095

UNITRODE CORPORATION

7 CONTINENTAL BLVD. • MERRIMACK, NH 03054

TEL. (603) 424-2410 • FAX (603) 424-3460