1.8 V fixed LDO — 500 mA rail for noise-sensitive loads
The ADP7105ARDZ-1.8 is a single-output LDO linear regulator from Analog Devices, delivering a fixed 1.8 V at up to 500 mA from a maximum input of 20 V. Control features include Enable, Power Good output, and Under Voltage Lockout — the Power Good flag lets a downstream FPGA or MCU sequence its core rail after the 1.8 V settles, avoiding indeterminate logic states on power-up. Protection covers Over Current, Over Temperature, and Reverse Polarity, so a miswired bench supply or a short on the output won't cascade into the upstream rail.
Package and thermal — exposed pad matters
Housed in an 8-SOIC with exposed pad (0.154" body width), the ADP7105ARDZ-1.8 relies on the pad for heat sinking. The copper area under the pad on the PCB sets the junction-to-ambient thermal resistance — a solid ground-plane pour with multiple vias drops the RthJA significantly compared to a standard SOIC-8. The tube packaging suits prototype and low-volume builds; the same die is also available in tape-and-reel as ADP7105ACPZ-1.8-R7 for production reels.