The STMicroelectronics LD39020ADTPU18R is a single-output, positive fixed LDO regulator delivering 1.8V at up to 200mA. It's built for noise-sensitive rails where PSRR matters — the 80 dB at 1 kHz dropping to 55 dB at 100 kHz cleans up switching ripple from a preceding DC-DC converter.
Package and mounting — field-swap reality
Package is 4-DFN (1x1 mm), surface-mount only. The exposed pad needs a via stitch for heat dissipation.
Protection features — built-in safety nets
Over-current, over-temperature, and soft-start protection are on-chip. Soft-start limits inrush at power-up.
It's a current-production part from ST, available through independent distribution. Pricing and stock are confirmed at quote time — submit an RFQ for the current market picture.