The NCP551 series of fixed output low dropout linear regulators are designed for handheld communication equipment and portable battery powered applications which require low quiescent. The NCP551 series features an ultra-low quiescent current of 4.0 mA. Each device contains a voltage reference unit, an error amplifier, a PMOS power transistor, resistors for setting output voltage, current limit, and temperature limit protection circuits. The NCP551 has been designed to be used with low cost ceramic capacitors and requires a minimum output capacitor of 0.1 mF. The device is housed in the micro-miniature TSOP-5 surface mount package. Standard voltage versions are 1.5, 1.8, 2.5, 2.7, 2.8, 3.0, 3.2, 3.3, and 5.0 V. Other voltages are available in 100 mV steps.