IC 7660 showing -2.5 v ?

[Sharagim]

Hello,
With a typical circuit as datasheet with a IC 7660 I am getting -2.5v between pin 5 and GND is this correct (Vin is +5v)?

BR,

 

[FvM]

In a (correctly built) typical circuit, 2.5V output would be achieved with about 40 mA load current.

 

[Sharagim]

but isnt it a 5v >>> -5v ? why -2.5?

 

[KonstanU]

No. It is very bad result. It means that you have overload. What is your load and what storage capacitors do you use (nominal capacitance)?

 

[Sharagim]

load is a voltmeter only and I use a 10u capacitor between pin 2 and 4

 

[KonstanU]

But, what about capacitance between output and ground?

 

[Sharagim]

Sorry I forget it , when I put it there (10u) now I see -5
10u is ok ? or I should use more?

 

[KonstanU]

10u is OK. In your case there is no reasons to try change recommended value because you have very low load (high input impedance of voltmeter).

 

[snail888]

Hi,the exact result should be -5V.And could you post your circuit?