Active LDO for a 1.9 V local rail
The TCR2EF19,LM(CT is a fixed-output 1.9 V linear regulator from Toshiba's TCR2EF series, rated for 200 mA continuous output. With a PSRR of 73 dB at 1 kHz, this LDO attenuates input ripple by a factor of ~4500 — useful for powering analog front-ends, sensor bias rails, or low-noise oscillator supplies where a switching regulator's ripple would couple into the signal path.
Dropout, quiescent current, and thermal budget
Maximum dropout voltage is 0.31 V at 150 mA. For a 1.9 V output, the input must stay above 2.21 V at that load — a 3.3 V rail or a 2.5 V rail with margin works. The 60 µA quiescent current is moderate; in a battery-powered design drawing 200 mA load, the Iq adds 0.03 % overhead, negligible for most applications. The SC-74A package has no exposed pad, so thermal resistance depends on PCB copper area. At 200 mA and a 1.4 V drop (5.5 V input to 1.9 V output), dissipation is 280 mW — within the package's capability with reasonable copper on a standard FR-4 board.