KA7905 DATASHEET PDF
March 24, 2020 | by admin
KA A 1 Amp -5V Voltage Regulator. Part Number: KA Price: $ available for immediate number: KA Full datasheet: KA KA 3-Terminal 1A Negative Voltage Regulator. Features. Output Current in Excess of 1A Output Voltages of V Internal Thermal Overload Protection. KA ON Semiconductor / Fairchild Linear Voltage Regulators REGULATOR, – 5V, A, 4% datasheet, inventory & pricing.
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Well, I bought a new L by ST. So, according to our measuremets, you can get up to 20V at the output of a L without a load. Tomas Kouba Jan Rehak Translated by: In most cases, only a single sample of a given type by a given manufacturer was available; exceptions are MC 3 samples measured and, of course, stabilizers by ST 5 samples of each type measured; dattasheet purchased at different times in different stores.
We have contacted local subsidiary of the Motorola company since they develop and manufacture similar series of IC’s here in the Czech Republic. The internal schematics of 79xx and 78xx are very different you can see both internal schematics in datasheets, datashedt are kx7905 at the end of this article.
There is no such information in L79xx datasheets see picture way above. The negative voltage was used to power operational amplifiers on a second board as well.
The company says, that they make compatible parts. Recommended operating circuit is shown. This is probably the cause of the problem. Possible cause of the problem: As I have said at the beginning of this article, I believe this fault is significant enough that we should inform about it.
So, we examined the datasheets more closely. If this is an intention to reduce internal consumption of the circuit to a minimum, at the expense of problems with output voltage with no load, it should have been mentioned in the datasheet. The whole thing worked about a year or so.
Voltage regulators (stabilizers) 78xx and 79xx
We will be glad to publish a response from the manufacturer, as well as readers’ comments to this issue. Figure shows the dependencies of the output voltage on the input voltage for a L, TAS, KA; both with and without a 1k load.
However, the fault does not occur for commonly used input voltages. Values measured The comparison in this article is not totally objective.
PDF datasheet of a 79xx by National Semiconductors. There, they do clearly state that the output voltage is guaranteed in a certain load current range; however, there is NO warning, that a voltage four times higher than the nominal output can appear at the output pin.
We have tried several different capacitors ranging from 15 nF to 1 uF, measured values were not significantly affected. Of course, the output voltage may fluctuate; however, it can’t be four times the nominal output voltage. Conclusion is, that oscillations are not the cause of our overvoltage problem. The TAS is interesting too – it has the same fault. Again, there was V. Unfortunately, we could not get a sample to measure. Then, we have studied carefully the datasheets. As a supply, we have used a BS DC power supply and a transformer with one-way rectifier.
So, keep this possibility in mind when designing your own applications. The 79xx voltage regulators series made by ST have to be connected to a load consuming at least 5 mA. The situation is similar with other stabilizers.
Voltage regulators (stabilizers) 78xx and 79xx |
May – 0: Stabilizers by ST differ, beginning from a certain voltage. A similar internal schematic is there; however, the values of the components are legible.
In datasheef LM datasheet by the same company, minimal load current is specified see picture below. We do our own development, too, and we do understand that it is not that easy to design and document something. The fault is definitely caused by ST, the manufacturer.
KA Datasheet PDF –
For datashheet, input current of a positive voltage stabilizer is mentioned, too. Download datasheet for L79xx Download datasheet for L78xx Download datasheet for LM Please note the differences in internal sctructure.
Consumption no load Consumption 1k load LCV 1. However, components by other manufacturers behave differently. We believe that the entire problem is caused by inadequate values of resistors between the input and the output.
Input voltage 26V DC. The fact that we found this fault in ST parts only does not signify that other manufacturers’ ICs are free from it. The ST stabilizer is clearly distinct.