Where the 28V input and 30mA output matter
The headline number here is the 28V input maximum — that is unusually high for a linear regulator this small. It means you can pull power directly from a 24V industrial supply, a 12V automotive bus through load-dump transients, or an unregulated wall-wart without stacking a switching pre-regulator. The trade-off is the 30mA output ceiling: this is a bias-supply part, not a rail for a microcontroller or a sensor heater. Typical loads are the always-on wake-up controller, a CAN transceiver in standby, an op-amp reference, or the keep-alive rail for an RTC or SRAM.
The MAX1615EUK+T comes in the SOT-23-5 package — five pins. That is a hand-reworkable footprint with a fine-tip iron or hot air.