Part Number: LM78L12, Maunfacturer: National Semiconductor, Part Family: LM, File type: PDF, Document: Datasheet – semiconductor. VOLTAGE REGULATOR. LM78L TO Lead Plastic Package. 2. It is recommended that you completely review our Data Sheet(s) so as to. LM78L12 Linear Voltage Regulators are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for LM78L12 Linear Voltage Regulators.
|Published (Last):||28 July 2017|
|PDF File Size:||18.22 Mb|
|ePub File Size:||5.31 Mb|
|Price:||Free* [*Free Regsitration Required]|
But another manufacturer Texas Instruments have different C1 recommendation on their datasheet which is 0. For C1, can I use these three caps in parallel as their sum is 0.
From Texas Instruments datasheet:. If the device is more than six inches from the input filter capacitors, an input bypass capacitor, 0. Although all the circuits datasheey Fairchild data sheet show 0.
As the TI datasheet says 0. Better than 3 capacitors in parallel. If needed, use 0. When using large capacitors at the output of these regulators, a protection diode connected input to output Figure 15 may be required if the input is shorted to ground. Without the protection diode, an input short causes the input to rapidly approach ground potential, while the output remains near the initial VOUT because of the stored charge in the large output capacitor.
The capacitor will then discharge through a large internal input to output diode and lm78l2 transistors. If the energy released by the capacitor is large enough, this datashwet, low current metal, and the regulator are destroyed. The fast dagasheet in Figure 15 shunts most of the capacitors discharge current around the regulator. So you are free to pick appropriate capacitors for input and output to reduce ripple, noise, etc.
LM78L12 Datasheet(PDF) – National Semiconductor (TI)
I’d go with the application information as indicated by the TI datasheet. The Fairchild datashset is limited to just data, with minimal application guidance.
Ci can be as large as you want. A 0 impedance input voltage isn’t going to hurt the regulator. In fact, the lower the better. What you quote doesn’t say what Co needs to be, only what value the rest of the specs are for.
You have to look elsewhere in the datasheet to find the min and max allowed values. If I remember right your job to checkthe 78xx series regulators are stable with 0 ESR output caps. The only real limitation is therefore the initial surge current as the output cap is charged up.
Since these regulators protect themselves from output shorts, there is effectively no upper limit from the regulator’s point of view.
LM voltage regulator is recommended to be used with decoupling capacitors at its input and output as in the below ratasheet And here is the part from the manufacturer Fairchild see recommended C1 is 0. I have two lm78l21 I’m not sure those are exactly recommended values. Rather those are what THEY had on hand to build the test circuit with and tabulate the numbers. Trevor I put 0. But what if I use a single 0. Another thing I never understood sometimes they put decoupling caps for power rails in parallel like 1u and n ect.
But 1u already does the job of n. Do you have any idea about it? There’s no sense in trying to get closer than that.
It really does not matter much. Those values are really the recommended minimums. You see them in parallel because different cap types have different high frequency characteristics. Some low ESR caps in parallel with some bulk 10uF caps won’t hurt. Paralelling is a little less common these dataeheet since you can get some pretty large value ceramics nowadays. Trevor Oh never thought of it. Did I get you correct?
From Texas Instruments datasheet: CI is required if regulator is located an appreciable distance from the power supply filter. On the output, TI states: StainlessSteelRat 3, 6 Olin Lathrop k 30 You mean tantalum type?
No, I mean caps with 0 ESR. Of course there is no such thing, but some technologies, like ceramic, have low ESR with large enough values to be useful in this application. Sign up or log in Sign up using Google. Sign up using Facebook.