680 nA quiescent current — the always-on rail enabler
The Toshiba TCR3UG50A,LF is a single-output, positive fixed LDO regulator delivering a regulated 5V rail at up to 300mA. Its standout feature is a quiescent current of just 680 nA, making it a strong candidate for battery-powered systems, IoT edge nodes, and always-on microcontroller supply rails where every microamp counts. The 70 dB PSRR at 1 kHz keeps ripple from upstream switching converters from coupling into sensitive analog or RF loads, while the 195 mV maximum dropout at full load means the input rail can sag to 5.195 V before the output drops out — useful in single-cell Li-ion designs where the battery voltage decays toward 3.6 V with a boost converter ahead of this LDO.
At 300 mA the dropout voltage is specified at 195 mV max. That tells the power-budget engineer the minimum input-to-output differential required: if the 5 V output must stay regulated, the input must never fall below 5.195 V. The device includes inrush current limiting, over-current protection, and thermal shutdown — three protections that let you skip an external current-limit resistor or a separate thermal watchdog in many designs. The enable pin (Control Features: Enable) allows the system to gate the regulator on and off, cutting quiescent draw entirely when the load is asleep.
Package and temperature — assembly and environment check
Housed in a 4-XFBGA, WLCSP package with a 0.65x0.65 mm footprint, this LDO is sized for space-constrained PCBs in portable or wearable products. The surface-mount WLCSP requires careful handling during reflow — stencil design and solder-paste volume must match the small pads to avoid opens or shorts.
Lifecycle and sourcing posture
It is ROHS3 compliant.