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DC2973A / LTC3337 Does Not Power on Loads Greater than 20mA

Category: Hardware
Product Number: LTC3337
Software Version: N/A

I am using the DC2973A Demonstration Board to evaluate the LTC3337 battery monitor.
I am using a Lab' PSU set to 2.9V and resistors to simulate a load; with all the IPK links set to 1 for 100mA peak load.
Our target has very low quiescent current, with periodic peaks when the device wakes up.
I initially used a 47K load, to simulate quiescent current, and the the system works as expected.
If I use a 47R resistor to simulate a running system at 60mA, the LTC3337 limits the current to about 20mA on power on and locks up in this state, with an output voltage of 0.97V.
However; if I power the system with the 47K load; and then use a switch to add the 47R in parallel with the 47K load; the PSU is sourcing 60mA and there is 2.75V across the load resistors.

Is this a one off problem with my DC2976A board, or is this a limitation of the LTC3337 device?

Parents Reply
  • Thanks for the explanation.
    I now know what the Start-Up BAT_OUT = 0V reference is on the datasheet; but the meaning - to me at least - is ambiguous; might I suggest that any future revision of the datasheet includes a note that the device locks on to this current limit until the BAT_OK line comes up?

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