LM340: TO-220FP type LM340

Hi,

The tab/case back on the LM340 TO-220 is a Ground connection to the die.

If you need to isolate the metal tab from your board or heatsink, you can use non-conductive thermal interface material (pad) between the TO-220 case and your board/heatsink. You can use a nylon shoulder washer through the hole in the tab to isolate the mounting screw from your board or heatsink.

Can I use the way to control the voltage with some zener diodes on the ground, though it has the grounded metal tab ?

Do not have you the TO-220FP type LM340?

Hi Koichi-san,

The LM340 is not available in full pack TO-220FP with isolated tab.
The only two TO-220 packages available for LM340 are:

NDE 3-pin:
www.ti.com/.../mmsf014.pdf

NDG 3-pin:
www.ti.com/.../mmsf017.pdf

Can you please explain how you want to control the voltage with zener diodes? Are you trying to modify the output voltage?

I see.

I try to modify the output voltage as you say. Is not it basic method to adjust the voltage regulater's voltage with some diode on the ground terminal of the voltage regulator though I don't know basic electric knowledge?

Hi Koichi-san,

There are adjustable linear regulators available where you can set the output voltage using a resistor divider. Alternatively, you could look at other part numbers with more fixed output voltage versions. What are your requirements for input voltage, output voltage, output current?

I would like to just set the voltage X.1~X.9V. Is your answer more popular method than what I asked?

"The LM340 is not available in full pack TO-220FP with isolated tab. "
Is this including National Semiconductor brand items?
They had the several TO-220FP type ones.

Hi Koichi-san,

TI acquired National Semiconductor in 2011, 7 years ago. You will need to look at currently offered packages for LM340 from TI for orderable parts.

You will need an adjustable linear regulator to set the output voltage to the values you listed. Please look for a TI part number with adjustable output voltage.

"The LM340 is not available in full pack TO-220FP with isolated tab. "
Is this including National Semiconductor brand items?
They had the several TO-220FP type ones.
I found items, but there are not the type, so I asked.

My requirements is 12V input voltage, 9.X V output voltage, 1A output current.
Which part of the adjustable linear regulator do you recommend?

Can not I use TO-220 type LM340 with some diodes what I mentioned?
Can you answer yes or no.

Hi Koichi-san,

How do you propose to use diodes to change the output voltage?

TI does not sell products with the National Semiconductor brand or logo. You may be able to find old stock, but we do not sell products that are not in production.

You can use our selection tool to find the LDO you require:
www.ti.com/.../products.html

Here are some suggestions:
LM317
LM1086
LM117

There are not National Semiconductor brand now, National Semiconductor products changed to All Ti brand, right?