0.9 V fixed rail for noise-sensitive loads
The MCP1801T-0902I/OT is a fixed-output LDO delivering 0.9 V at up to 150 mA — a sub-1 V rail typically used to bias low-voltage logic cores, sensor front-ends, or RF transceiver supplies that need a clean, regulated feed from a higher bus voltage. With 70 dB PSRR at 10 kHz, this LDO attenuates switching-regulator ripple by a factor of ~3000 at that frequency — useful when the 0.9 V rail is fed from a buck converter that switches in the 500 kHz to 2 MHz range, where the PSRR still holds meaningful rejection.
Industrial temp grade and package constraints
The SOT-23-5 package (SC-74A) has a junction-to-ambient thermal resistance around 220°C/W typical — at 150 mA with a 0.9 V output and 5 V input, power dissipation is 0.615 W, which would raise the junction about 135°C above ambient, exceeding the 85°C limit. In practice, the LDO can deliver 150 mA only with adequate copper area or at lower input-output differentials. Quiescent current is 50 µA — not ultra-low for always-on battery applications, but acceptable for a rail that stays powered during operation and is disabled via the Enable pin when idle.
It is safe to design into new BOMs today. Fully ROHS3 compliant, with no exempt substances — no REACH or EU compliance risk for global shipments.