LM2936: output voltage is shifting to 100mV

Hello Murthy,

                     Could you provide us a few more details on your circuit, perhaps a snapshot of the circuit diagram, load current and initial VIN value? Thanks!

Regards,

Srikanth

Dear Sir,

Please find the attached Schematic in PDF.

Input Value: 12V
Output Volatge: 3.3V
Load Current: 10 to 15mA

Regards
MurthyTest Power.pdf

Hello Murthy,

                     The schematic, in principle, looks good. Could you add a 1 Ohm resistor in series with the output cap (C3) and verify if the output voltage shifts as much? I am concerned if C3 has sufficient ESR by itself. If you still observe the shift, could you provide us scope shots of Vin, Vout and Iout showing the this shift in Voltage? Thanks!

Regards,

Srikanth 

Dear Sir,

C3 has ESR of : 1.35ohm
Part No: EEEFN1C220R
Capacitance: 22µF
Voltage Rating: 16V
ESR: 1.35ohm

I will try to check by adding a 1E series resistor to the output cap.

Can you suggest an equivalent IC of the same footprint SOIC-8 and pin-compatible with an output current of (400mA to 500mA) @ 3.3V?

Regards
Murthy

Hello Murthy,

                     We do have some devices that have the same footprint and are pin-compatible (TL751L, TL750L, LM2931, UA78L & LM9036), but none of them can support 500mA of load current. The capacitor EEEFN1C220R has a maximum ESR value of 1.35Ohms, however I am not sure what its typical value would be. The device needs an output capacitor that has 0.8Ohm of ESR for stability. It would be interesting to see the impact of a 1Ohm resistor in series with the output cap. Thanks!

Regards,

Srikanth 

Sir, most of the Suggested IC's for 5VDC Output,

Can you suggest an equivalent IC of the same footprint SOIC-8 and pin-compatible with an output current of greater than 100mA @ 3.3V?

100mA Output current is also enough Sir.

Regards
Murthy