LP2998-Q1 Shutdown Current

Hi Kei Sato-San,

The Shutdown current has a max rating of 150 uA, when AVIN=PVIN=VDDQ=2.5V, so I'd assume the shutdown current will not be as high for PVIN=VDDQ=1.5V.

There shouldn't be "amperes" of current flowing through AVIN, VDDQ, and PVIN when Shutdown is pulled low, as the part is off. However there is a small amount of current in the "uA" flowing through VDDQ and AVIN. 

Therefore, I'd say there will be less than 150uA of current when Shutdown is pulled low to 0V.

Thanks,

Shashank

Hello Shashank,

Thank you for reply.

I think that shutdown current becomes larger than 150uA when AVIN = 3.3V.

Please check Figure. 8 of the datasheet p6.

Please tell me total shutdown current of LP2998 at "AVIN=3.3V PVIN=VDDQ=1.5V SD=0V"

Kei Sato

Hello Kei Sato-San,

I was looking for an a graph with Shutdown current, but somehow skipped right over that one. According to that chart, looks like the shutdown current is slightly higher than 150uA. That chart is for PVIN=2.5V, so there might be less leakage at a lower PVIN.

Thanks,

Shashank

Hello Shashamk,

Thank you for reply.

Question1

Is the total shutdown current rigth a calculation formula below?

I_SD(total) = I_SD + IQ_SD + (VDDQ / Z_VDDQ)

Question2

Is "I_SD" 190uA when AVIN=3.3V? (by Figure 8)

Is " (VDDQ / Z_VDDQ)" 15uA when VDDQ=1.5V?

What kind of shutdown current is " IQ_SD"? Is "IQ_SD" PVIN shutdown current?

Hi Kei Sato-San,

Yes, the total shutdown current is I_SD + Iq_SD + IDDQ      where IDDQ=(VDDQ/Z_VDDQ)   and Z_DDQ=100kOhms

You can also look at figure 3 which is a little clearer since it doesn't show three different curves for the temperatures. According to this, at room temp, the Iq at SD for AVIN=3.3V is around 175-180uA.

Yes, I_DDQ=15uA when VDDQ=1.5V since Z_VDDQ is 100kOhms.

I'm not 100% sure what IQ_SD current is. I'll have to double check.

Thanks,

Shashank

Hello Shashank,

Thank you for having you reply to various questions.

Please check about IQ_SD and tell me.

Hello Shashank,

progress -- how is it?

The customer is waiting for your reply.

Thank you.

Hello Shashank,

There are some additional questions.

Please tell me the total shutdown current max value.

Question

What uA is the maximum of I_SD at the time AVIN=3.3V?

What kohm is the maximum of Z_VDDQ?

What uA is the maximum of IQ_SD at the time "AVIN=3.3V PVIN=VDDQ=1.5V"?

Hi Kei Sato-San,

Sorry for the delay!

The SD pin has an internal pull up to AVIN, so I'm sure the IQ_SD is leakage current from that path.

As for your other questions, haven't these been already answered in the previous posts?

The max uA of I_SD when AVIN=3.3V is around 180uA.

Z_VDDQ always keeps its impedance at 100kOhms.

IQ_SD max spec is 5uA.

Thanks,

Shashank