# Power consumption of TDA8029 USIM controller for 3V/5V cards

we are using TDA8029 in one of our application board. Just a summary of the circuit.

TDA8029 in our board connects a USIM card and reads the data and sends on UART.

In our board, 2 supply inputs of TDA8029 VDD, VDCIN are connected to 3.3V and we have support for 3V and 5V cards.

We need to find the TDA8029 current consumption for below 2 cases

1. VDD=VDCIN=3.3V and 3V card
2. VDD=VDCIN=3.3V and 5V card

Below picture shows current consumption for other cases.

There is no support from manufacturer currently. How to interpolate/approximate the current for the above 2 cases.

One more thing, as Card power is driven from controller after detecting the card, for table shared above in picture.

for VDD=2.7V 5V card Idd = 250mA but card current is 65mA --> Actual TDA8029 current consumption is 250-65= 185mA

For VDD=2.7, 3V card TDA8029 alone current 125-50 = 75mA (excluding card current)

For VDD=5V, 3V card TDA8029 alone current 65-50 = 15mA

All these 3 situations are giving 3 different values of current consumption for TDA8029, which i couldn't able to interpret correctly. What could be wrong. please help.

There are similar controllers from other manufacturers with 80C51 core like SEC1120/SEC1100 or 73S1209F - These controllers have very less current consumption in 10-30mA.

Is there any issue with datasheet or my interpretation.?

• I don't have that device, but after researching I think I found the reason for that supply current data. However, I see that you haven't accepted any answers to your previous 21 questions, so it seems that you have very high standards! So before I spend lots of time writing a full answer, I want to understand - are you looking for 100% certainty, like it appears that you wanted in your previous questions? Perhaps I should wait to see if someone who has that device, can answer? Or you might get an answer first where you asked at edaboard? Dec 2 '17 at 4:35
• @SamGibson : i prefer answers in general proven by engineering assumptions/datasheets/measurements. But i never followed a pattern for accepting answer/ any preference for answer. I need help . at last about Qtn, I have seen similar controller SEC1120/SEC1100/73S1209F their currents are in max 30mA and even 80C51 CMOS controller will have currents in same range. I don't know why these datasheet mentions current of 250mA...huge....we are seeing many thermal issues.... Dec 2 '17 at 11:25
• "we are seeing many thermal issues" I don't understand how you are seeing those issues, since you explained in your parallel question on edaboard that you "don't have that board [...] with us currently. No measured data even.". Perhaps you expect to see those thermal issues? Anyway, as I said, I don't have that device so my research work produced a (IMHO good) hypothesis which fits your data (and similar data from elsewhere) but is not proven. Therefore since proven answers are what you want, I won't waste any more time. Good luck! Dec 2 '17 at 15:53
• i need help Sam Gibson. need not require any proof. thermal issues are in preliminary simulations, where current consumption is major factor. if you have any data please share. it will definitely v help me Dec 2 '17 at 16:39