So I was attempting my first use of a DS1307 Real Time Clock, and had the most miserable failure imaginable. I was using the surface mount module, and I had made a custom circuit board for it. I want to interface the device with a PIC16F874A. I got everything set up and plugged in 5 volts, and a few seconds later the DS1307 started smoking. I figured it must be some sort of basic hardware error, so I got out the multimeter and started checking for shorts. But I couldn't find anything wrong. VCC was getting 5V, the ground checked out, no short across the crystal, etc... So what could make a DS1307 explode? One thing that I could find no information on was whether the SQW/OUT pin required a connection (I just left it floating). So I tied a 10K pullup to SQW and the thing still heated up (of course, the IC could have been permanently fried at that point).

So I figure one of two things is happening. 1) the IC was damaged to begin with or 2) I am ignorant of something fundamental about using the device.

Here are some details that will be of interest to all you DS1307 experts: I'm not using a battery; Vbat is attached directly to GND. I have 10K pullup resistors on SCL and SDA. When I powered the board up, I did not have the PIC installed, so SCL and SDA were attached to nothing but the pullups.

So am I missing something, or do I have a bad IC? I've got another factory-fresh DS1307 that I can install, but I'd like to hear some advice before I potentially trash another IC. Thanks for any help.

Search terms: DS1307, RTC, overheating, burned up