The PG pin pull up to the 3.3V_ASIC by 1M ohm resistor then connector to the other TLV62085's enable pin. When the temp is lower about 70 degree it is work,
When The temp higher over 70 degree the PG pin's voltage only has 0.9V. (3.3*400k/1400k.) It's 3.3V_ASIC output is still correct 3.3V but PG signal could not push the the next power IC.
I need to reduce the 1M ohm to 10k or 100k that it can work normally.
Channel 1 (Y): Vout . Channel 2 (B) : PG. When the pull up resistor is 1M ohm, PG Pin Could not go to High to push the next TLV62085 that the channel 3 power could not wake up.
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Channel 1 (Y): Vout . Channel 2 (B) : PG. When the pull up resistor is 10k ohm, PG Pin is work.
Hello Pingyuan,
The PG pin clamps to 0.8V with 1Mohm pull-up resistor (R444) is due to increase on input leakage current (~2.5uA) into PG pin at high temperature. Decreasing the R444 value to 10K will compensate in the drop in PG pin voltage. See figure below for details.
To calculate for R444 value, determine the minimum high level for PG (PGhigh_min) for the 1.5VDDR to enable. Adding a 20% margin on ILK is highly recommended.
R444 = (3.3V - PGhigh_min) / ILK
Best regards,
Excel
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Hi Regidor sir:
I could not find the relationship about the temp and leakage current on the SPEC,
It describe the average leakage current IPG about 0.01uA and It also use the 1M ohm pull up resistor on the PG pin on the SPEC (Typical Application).
I have another question about the following figure.
How to confirm the enable pin is working or the pull down 400k ohm resistor is exit or not.
