Using UCC28C43 as 5V regulator

[cupoftea]

Hi,
Looking on www's for 5v reg thats in stock and likely to stay so.....cant find many of any at all.......what about just using the VREF outptu of a UCC28C43 and being done with it....ok its 4.9V to 5.1V but thats close enough for driving Vcc(max) opamps of 5.5V.

Supplies 20mA happily, which is plenty

UCC28C43

https://www.ti.com/lit/ds/symlink/ucc28c43.pdf?ts=1649852088463&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FUCC28C43

 

[stenzer]

Hi,

why aren't you considering a zener-BJT voltage regulator, if you are not that concerned about the accuracy? By using the discrete approach, one would be more flexible by means of selecting the diode as well as the BJT. For further flexibility, you could even design a Darlington structure (two single BJT packages & 0 Ohm bridge). So you would be able to use a 5.6 V zener and a single BJT or a 6.2 V zener and two BJTs. But of course, this approach highly depends on your input voltage and your ambient temperature. If you are using opamps which accept input voltages of ~6 V (> 5.5 V), you could use a 6.2 V zener and a single BJT, which would have the best temperature stability.

BR

 

[FvM]

Digikey lists more than 600 different SMD 5V linear voltage regulator types on stock. Don't understand which problem is addressed by this thread.

 

[KlausST]

Hi,

I agree with the others.
On the other hand I don´t see a big problem to use it. Even the datasheet talks about "external loads" at VRef.
You are surely on the safe side if you use some kind of buffer.

Klaus

 

[cupoftea]

...Very sorry i forgot to add, its for going on a 4kw main power SMPS board, so must be thru hole.
Sorry i forgot to add that.
Theres very little in PTH.....i mean, a DPAK might be ok because its not likely to get warped or dry jointed by the board bending/abuse that happens to an 4kW SMPS main board....ucc28c43 comes in DIP, so it would be ok

 

[FvM]

...Very sorry i forgot to add, its for going on a 4kw main power SMPS board, so must be thru hole.
Sorry i forgot to add that.
Theres very little in PTH

O.k., only 150 devices on stock at Digikey. You can choose between TO92, DIP8 and TO-220 at least..

 

[stenzer]

so must be thru hole.

I do not know where you are located at, or what's the required quantity, but a LM7805 or LM317are classic candidates in a TO-220 package. Those are THT components you even get in the "smallest" / "worst assorted" electronics store. At my local dealer (non store-chain), I'm getting L7805CV regulators for 0.40 € per piece. TI has over 11 k in stock right now, and for a quantity of 1k+ the LM7805 is even cheaper than the UCC28C43P (0.668 € @ 1k+ @ TI).

 

[Easy peasy]

you did not state the current required - a 4v7 zener and a schottky diode can create a 5V reference, for higher currents out an emitter follower with a 5v6 zener base to gnd, will give 5V out, just choose a suitable C-B resistor to give 5mA in the zener, and a suitable npn xtor to drop the volts without overheating ... ( a green & amber LED in series also give ~ 5.5 volts for same use )

or as above the 7805 IC in all its forms, TO-92, TO-220 ...