HAL740 replacement

Hi Everyone.

I’ve been looking for a hall effect sensor to replace HAL740SF-K or HAL740SF-E which is obsolete now. We bought a huge stockpile when it went EOL but we will soon run out of them.

It was SOT89B, It was dual output (North and south), Its open drain, Unipolar (ie the pin will stay high as long as field is present and go low once removed), Threshold is 8 to 11mT or 80gauss to 110gauss and ran at 5V.

Ideally, I would like a pin to pin compatible replacement. If not I like to find a replacement thats at least dual output, unipolar runs at 5V and about the same sensitivity.

Please advice.

Unfortunately I am not having any luck finding an option that is a Dual Unipolar switch and Open Drain. The package is also a basic no go.

Here are some options, however both will require modification.

EM1791TR-ND ia a Dual Unipolar Switch, however Push/Pull Output. It does accept the 5V, sensing range -3.5mT Trip, -1.1mT Release; 3.5mT Trip, 1.1mT Release in a 4-SOP package.

TLE49643KXTSA1CT-ND would keep the open drain output, however is a single Unipolar switch. will also accept the 5V with a sensitiity of 12.5mT Trip, 9.5mT Release so we are off there. and a package of TO-3

Hi Robert,

Thank you for getting back to me so quickly. The EM1791 looks pretty good. It is more sensitive but we can test and see if it works for us. Is it actively in production, I see it is out of stock on your website and mouser.

TLE49643 looks interesting too, but having only one polarity is a problem for us. In the past we used a similar IC, we have two on the PCB, and flipped one upside down and soldered it, our mechanical assembly won’t accept two-sided PCB. Flipping the IC and bending down the pins decreased their reliability.

I won’t mind single output hall sensors if they came in pairs where one is sensitive to the north pole and the other south.

Hello @kvikramg

The EM1791 is active, however not a part we actively stock. You may be able to request a sample through AKM using their Contact us Form.

I am not having much luck in finding a matched pair. It may be possible to find two parts that would work individually with a north/south pole.