Consider this: your boss just gave you a power supply design to finish that was started by a co-worker. He just retired and now it’s your turn to finish his job. The design calls for a 3-A buck converter, but the last 3 projects you've worked on have had last-minute increases to the load current requirement. There’s this funny feeling in your gut that this might happen to you again. What’s the prudent design engineer to do? What decisions can you make to minimize your risk of needing to entirely redesign this power supply?
For cases like these, pin to pin compatible devices are a lifesaver. Very similar devices with the same pinout and different load current levels. If you need more (or sometimes less!) current, just plop a different part number into your design and leave everything else the same. Use the higher current device when the load current requirements increase and the lower current ones when the power estimates weren't even close. A scalable power supply. What a great idea!
The TPS62095 is the latest such device. Pin to pin compatible with its 3-A predecessor, the TPS62090, the TPS62095 offers 4A of output current in the same 3 x 3 mm package (following schematic shows the device supporting a 1.8V output application).
For higher input voltages, the TPS62150A, TPS62140A, and TPS62130A are 1-, 2-, and 3-A buck converters in a similarly small 3 x 3 mm package. Don’t think you need an entire Amp? The TPS62125 (300 mA), TPS62160 (1000 mA), and TPS62170 (500 mA) are all pin to pin in a 2 x 2 mm package. Quite a few lifesavers for your next scope-widening, power supply design.
How have pin-to-pin compatible devices saved your designs?