Low Dropout Regulators

[vik1501]

Plz suggest me some commonly available LDOs 3
Input Voltage Range = 5-8 V
Current = 1A

I tried LM2940...... But something wrong is happening. The o/p voltage increases as the i/p voltage........ when i/p is say 6 V o/p is something like 5.2..... But when i/p is increased further to say 9V... still o/p becomes 8.2 .....when in actual case it should not go over 5 V. :roll:


Regards,

 

[Nigel Goodwin]

Plz suggest me some commonly available LDOs 3
Input Voltage Range = 5-8 V
Current = 1A

I tried LM2940...... But something wrong is happening. The o/p voltage increases as the i/p voltage........ when i/p is say 6 V o/p is something like 5.2..... But when i/p is increased further to say 9V... still o/p becomes 8.2 .....when in actual case it should not go over 5 V. :roll:

Are you sure you've connected it the correct way?. Many regulators include a reverse biased diode from input to output, if you connect the input and output the wrong way round this diode is then forward biased - resulting in the output being about 0.7V less than the input.

 

[vik1501]

How to Interface DTMF generator with Telephone Line

I DID it !!!


The problem is after all not following the datasheet word by word :shock:

I simply missed input capacitor of 0.47 uF & o/p cap of 22uF shown in national datasheet thinking that they are not useful for testing purposes????? :evil:

So friends my qdvice to you "Follow each and every word given in datasheet, or u will make bullsheet of your work"

 

[Nigel Goodwin]

Re: How to Interface DTMF generator with Telephone Line

I DID it !!!


The problem is after all not following the datasheet word by word :shock:

I simply missed input capacitor of 0.47 uF & o/p cap of 22uF shown in national datasheet thinking that they are not useful for testing purposes????? :evil:

The capacitors are crucial to the operation of most three pin regulators - without them they tend to oscillate - which is presumably what yours was doing?.