Issue with different circuit performance using CD4501B DIP and SOIC packages

Sasuke,

Thank you for providing some details and diagram around your question.  The CD4501B device only comes in leaded packages and does not come in a surface mount package. 

When you are changing out packages are you referring to different resistor packages?  Have you measured the resistance of the resistors in your network in both package types?  Are these circuits on two different boards?  Maybe there is some leakage path due to some residual flux that is causing your voltage to drop. 

I have contacted the engineer supporting CD4051B products for more help.

Thank you,

Adam

thanks for the reply,

no i am talking about the ic. and this is a part of a complete hardware. I TYPED WRONG ABOUT PACKAGE [my bad]ACTUALLY I WAS TALKING ABOUT PDIP AND SOIC.

hello shreyas

"The PDIP and SOIC both have the same internal die as I checked now . 90uA is little tiny current to work with on the logic switches which consume almost 20uA Idd current at room temp and up to 600uA at high temp."

[Sir, may be 90 u Amp is too tiny current, but thing troubling me is both packages should have perform same.and how ic input current is going to effect  switching of tiny current source]

"what is meant by " it gives 7.6 volt and reduces to 6 volt " is it initial 7.6V transient which settles down to 6V ?
where else is the voltage drop being developed if not at the 100kohm , is the current still 90uA at the COM pin?"

[Let's consider a case to explain my question

1) lets say, i connect a 100 k resistor to the channel 0 of CD4051 and ground the other end of resistor. Now i apply a constant current source of 90 uA to o/p of   cd4051 and power up the mux [vcc = 15V].  then i switch to the channel 0.   ideally my current source (without any leakage) will flow through resistor connected to channel 0 and i should get a voltage drop of 9 V.

but in case of PDIP package i get 8.998 V and in case of SOIC i get different [reduced] voltage which is not stable it further reduces to lower value. and it is not transient it reduces slowly .

and current source entering to mux remains same.90 u Amp

]

the only explanation i could think of is on state leakage current plus off state leakage current per channel. since my current is too low and a few u ampere leakage will result in notable change (since resistance is too high and total leakage of 20 uA will result in  2 volt drop ,7 volt instead of 9 V)  

BUT  DATA SHEET SPECIFIES LIKE BELOW

but again the same question WHY NOT IN DIP?

hello shreyas,

well, since i required 15 PDIP packages in my applications so i have tested 15 and those are working fine. and tested around 20 SOIC packages none of them works. why don't you check it on your side if possible.

hello shreyas,
                           any updates on problem???