LM1117MPX-3.3/NOPB

The LM1117MPX-3.3/NOPB is an 800mA low-dropout linear regulator from Texas Instruments, providing a fixed 3.3V output with +/-1% accuracy ensured by a Zener-trimmed bandgap reference. The 1.2V dropout voltage at 800mA allows operation with minimal headroom, while the wide input range (up to 15V) provides flexibility in power supply design. Built-in current limiting and thermal shutdown protect both the device and the load. The SOT-223 package offers a compact footprint with adequate thermal performance for moderate dissipation applications.

The LM1117 uses a PNP pass element to achieve low dropout voltage. An error amplifier compares a divided-down version of the output voltage with an internal bandgap reference (trimmed by Zener zapping for +/-1% accuracy). The amplifier drives the PNP pass transistor base to regulate the output. When the input-output differential falls below the dropout voltage, the PNP saturates and output tracks input minus Vdropout. Current limiting activates when load current exceeds the safe operating area, and thermal shutdown disables the output when junction temperature exceeds approximately 160C.

• 3.3V rail generation from 5V supply in digital systems
• FPGA/CPLD I/O power regulation
• Post-regulation after switching converters for noise-sensitive loads
• Embedded processor and peripheral power
• Battery-powered device regulation