5V fixed rail for noise-sensitive analog supplies
The MCP1804T-5002I/MT is a 150 mA low-dropout linear regulator with a fixed 5 V output, designed for applications where a clean, regulated supply rail is critical — think sensor front-ends, ADC references, or MCU analog sections that cannot tolerate the ripple from a switching converter. Its 50 dB PSRR at 1 kHz means that a 100 mV ripple on the input at that frequency is attenuated to roughly 0.3 mV at the output — a meaningful margin for a 10-bit ADC's LSB budget.
Input headroom and dropout — sizing the supply rail
The maximum input voltage is 28 V, which lets this part connect directly to a 24 V industrial bus without an intermediate pre-regulator — a common requirement in PLC analog modules or field-transmitter power supplies. At lower loads the dropout is proportionally smaller, but the 1.3 V ceiling is the number to use for worst-case headroom budgeting. Quiescent current is 105 µA typical — low enough for always-on circuits in battery-backed systems, though not in the sub-µA class reserved for energy-harvesting designs.
Thermal and package considerations for the SOT-89-5
The part is offered in a 5-pin SOT-89 package (supplier device package SOT-89-5), which includes an exposed pad on the bottom — this is the primary heat path. Protection features include over-current and over-temperature shutdown — the regulator folds back or shuts off before the silicon exceeds its safe operating area, so the external circuitry does not need to guarantee fault-free operation.
Active lifecycle and compliance status
ROHS3 compliant, which covers the full ten restricted substances including the four phthalates — no exemption paperwork needed for EU or global shipments.