BQ24052 Output without battery

With TS floating I get 1.8v out with a 4.7v input. If I connect TS to the input I still get 1.8v. I have also tried connecting ISET2 to ground.

Do you have a schematic that you can post?  Are you testing this on your own board or the EVM?

On the EVM, it works as I have described.  The schematic for the EVM is here: http://focus.ti.com/lit/ug/sluu378/sluu378.pdf

With 4.7V in, JMP7 open, and JMP5 open, I get 4.2V on the output.

We are testing on our board.4532.reg.doc

I tested your schematic on the EVM and it outputs 4.2V.  There are two things I would change, however.

First, to disable the TS function, simply float the TS pin.  There is an internal pull-up current source, so you don't need to attach anything to it.

I wouldn't recommend the 10k pull-down on ISET2.  ISET2 is a voltage divider in the IC.  It will sit at 0.9V when you float the pin, so a 10k to ground is not the same as grounding the pin.

Do you have any load on the output?  The IC will only output a current, so if you have a load, it may be drawing all the current and keeping the voltage down.

Have you measured your voltages with a meter?

Without a load the output is 4.2v. When the load ( 300ma) is connected the output goes to 0v. If I read the data sheet correctly it should be capable of supplying 800ma. There are a number of capacitors in the load which could equal a total of 50uF. Is it possible that the surge current is more than the device can support?

Ah, you are loading it.  This affects things greatly.

What kind of load are you using?  Electronic loads often behave erratically and do not accurately represent what a real load will do.  I recommend using resistors for the load and repeating the test.

Also, your 10k to ground on ISET2 may be keeping the ISET2 pin in the voltage range at which it is 'floating'.  This would limit you to 100 mA current vs. grounded, where you get the ISET programmed current, which in your case is set to 540 mA.

Please make the changes to the load, ISET2, and TS and rerun the test.

If I am reading the spec on page 23 the ISET2 wants to be high for max current.

I don't think so.  Low = ISET current; float = 100 mA; high = 500 mA.

From page 23 "A low will program a regulated fast charge current via the ISET resistor and is the maximum allowed input/output current for any ISET2 setting, Float will program a 100mA Current limit and High will program a 500mA Current limit"

From page 8 (pin descriptions) "High = 500mAmax, Low = ISET, FLOAT = 100mA max."