The TLV1117CDCYG3 is a Texas Instruments adjustable positive LDO regulator rated for 800 mA output with a 75 dB power-supply rejection ratio at 120 Hz. That PSRR figure means it attenuates full-wave-rectifier ripple by roughly 5600:1 — a 100 mVpp 120 Hz ripple on the input becomes under 18 µVpp at the output, which is clean enough to feed an analog front-end or a 12-bit ADC reference without additional post-filtering. The output adjusts from a 1.25 V reference up to 13.7 V via an external resistor divider, so one BOM line covers multiple rail voltages across a design family.
SOT-223-4 footprint and thermal path
The supplier device package is SOT-223-4, which maps to the TO-261-4 case code. For 800 mA output with a 1.3 V dropout, the power dissipation is roughly 1 W; a 1-inch-square copper pad on a 2-layer board keeps the junction below 125°C at 25°C ambient. The 10 mA quiescent current is higher than modern micropower LDOs — this part is suited for line-powered or always-on rails where the 10 mA bias is a small fraction of the load, not for battery-operated gear where every microamp counts.
Protection features and temperature grade
Built-in over-current and over-temperature protection means the regulator self-limits rather than failing open — useful for a rail that might see a momentary short during board assembly or a field fault. The operating temperature range is 0°C to 125°C, which covers commercial and most industrial environments but does not extend below freezing; a cold-start at -20°C is outside the guaranteed operating window.