Does anyone know of a small ic package for a momentary latch?

For a momentary switch to turn something on and off

I know how to use one using bits, but would rather not have the headache

I have not found any ready made IC out there but I'm sure someone makes one.
anyone know of any?

 

I should clarify, small meaning 8 pin dip package area, does not need to be smt

 

I should clarify, small meaning 8 pin dip package area, does not need to be smt

A momentary latch AKA: a monostable - you can make that with a555.

 

a latch for a pushbutton switch to turn something on and off
as opposed to a slider or toggle switch

 

a latch for a pushbutton switch to turn something on and off
as opposed to a slider or toggle switch

That's a bistable, some manufacturers are producing individually packaged logic gates - there may also be individual flip-flop logic elements.

Or you could use 2 transistors and a handful of components.

 

That is true but i was trying to avoid having so many parts

 

I don't think such a part exists. AFAIK there have been very few new MSI IC's introduced since the late 1980's. Everything now is FPGA and microprocessors. So how about an 8-pin ATTiny and a few lines of code?

 

If you dont mind SMD package, there is at least one....

 

DM7475N

http://www.ti.com/lit/ds/symlink/cd74hc75.pdf

 

7475

http://www.ti.com/lit/ds/symlink/cd74hc75.pdf

Maybe you need a flip-flop not a lach

 

As Ian suggested, use a 555.

Connect pins 2&6 together. Fit a 10k resistor between those pins and V+.; that keeps the latch normally off.
Connect a momentary push button between pins 2&6 to V-.. The latch will turn on for as long as the button is pressed.

 

To turn a momentary pushbutton switch into an alternate-action function, you need a little debouncing and a toggle flipflop. Depending on the circuit voltage, you can use 7400 series TTL or 4000 series CMOS 14-pin chips. With the CD4013 you get two toggle flipflops in one package. There are specialized ICs for LED flashlights that are a single toggle ff in one SMT package, but you usually have to buy a large quantity.

ak

 

The NC7SV74 pdf linked above looks be what do you want!

 

Hello,

There is even a smaller one 1G80.

Bertus

 

Or you could just use one of these and not use electronics at all.... but what fun is that?
http://www.jpmsupply.com/product-p/70213.htm?gclid=CMC_n_eMncsCFQwPaQoduB0Beg

 

Or you could just use one of these and not use electronics at all.... but what fun is that?
http://www.jpmsupply.com/product-p/70213.htm?gclid=CMC_n_eMncsCFQwPaQoduB0Beg

Maybe the OP has a specific switch/button that they would like to use and so switching function needs to be designed.

My choice would be to use a µc, the ATtiny85 is an 8 pin package and is also available in SMT. The regular package is the same as a 555 but wouldn't require any external components, just an embedded programme.

 

Hello,

There is even a smaller one 1G80.

Bertus

That's the sort of thing I was thinking of.

Just wire not-Q back to the D input and the output changes state on every CP transition.

 

the problem is i need this thing to pass through about 300ma or so

maybe even 4 or 500ma from a source through it to other components

Still at a stand still with this. Tried several designs so far with no luck

http://www.edn.com/design/power-management/4427218/Latching-power-switch-uses-momentary-pushbutton

This is one i tried but can't make it work

 

Hi!
In this link, we have a lot circuits.
I think, you will can use a Darlington in the flip flop output with a resistor but you need to upload pictures and the flip flop you have with the schematic you has tried.

 

http://www.edn.com/design/power-management/4427218/Latching-power-switch-uses-momentary-pushbutton

That is a simple latch, and what you want is a toggle. In terms of circuit reliability, I think your best solution is to let the logic be logic and the power switch be a power switch: the single latch chip from above driving a small P-channel power MOSFET.

ak