Device description

RHFL4913A

8/20

Doc ID 10005 Rev 11

5

Device description

The RHFL4913A adjustable voltage regulator contains a PNP type power element

controlled by a signal resulting from an amplified comparison between the internal

temperature-compensated band-gap and the fraction of the desired output voltage value

obtained from an external resistor divider bridge. The device is protected by several

functional blocks.

5.1

ADJ pin

The load output voltage feedback comes from an external resistor divider bridge mid-point

connected to the ADJ pin (allowing all possible output voltage settings as per user

requirements) established between load terminals.

5.2

Inhibit ON-OFF control

By setting the INHIBIT pin TTL high, the device switches off the output current and voltage.

The device is ON when the INHIBIT pin is set low. Since the INHIBIT pin is pulled down

internally, it can be left floating in cases where the inhibit function is not used.

5.3

Overtemperature protection

A temperature detector internally monitors the power element junction temperature. The

device turns off when a temperature of approximately 175 °C is reached, returning to ON

mode when back to approximately 135 °C. Combined with the other protection blocks, the

device is protected from destructive junction temperature excursions in all load conditions. It

should be noted that when the internal temperature detector reaches 175 °C, the active

power element can be as high as 225 °C. Prolonged operation under these conditions far

exceeds the maximum operating ratings and device reliability cannot be guaranteed.

5.4

Overcurrent protection

a typical value range of 10 k

unbiased (as it is in 3 pin packages).

5.5

OCM pin

buffered and can sink 10 mA. The OCM pin is internally pulled up by a 5 k

Ω resistor.