The REG103 is a family of low noise, low dropout linear regulators with low ground pin current. Its new DMOS topology provides significant improvement over previous designs, including low dropout voltage (only 115mV typ at full load), and better transient performance. In addition, no output capacitor is required for stability, unlike conventional low dropout regulators that are difficult to compensate and require expensive low ESR capacitors greater than 1F. Typical ground pin current is only 1mA (at IOUT = 500mA) and drops to 0.5A in "not enabled" mode. Unlike regulators with PNP pass devices, quiescent current remains relatively constant over load variations and under dropout conditions. The REG103 has very low output noise (typically 33Vrms for VOUT = 3.3V with CNR = 0.01F), making it ideal for use in portable communications equipment. On-chip trimming results in high output voltage accuracy. Accuracy is maintained over temperature, line, and load variations. Key parameters are guaranteed over the specified temperature range (40C to +85C).