Torex - 1A, 0.5v Ultra-low Dropout Voltage Regulator With Soft-start

It is thanks to its integrated N-ch driver transistor that the minimum input and output voltages of the XC6602 can be much lower than more traditional LDO’s with their integrated P-ch transistors. Another advantage of the XC6602 integrated N-ch driver transistor is that it dramatically reduces the on-resistance at low output voltages, leading to dropout voltages as low as 155mV @ 1A with VOUT=1.2V (VBIAS=3.6V). This makes the XC6602 ideally suited for low input/output voltage applications which require high output current and extended battery life.

With the XC6602, ceramic capacitors values as low as 1µF (VIN, VBIAS) and 2.2µF (VOUT) can be used, even with an output current of 1A. This can provide a very compact solution. Although the use of such small capacitor values contributes to lower the inrush current at start-up, the built-in soft-start circuit (XC6602A only) makes sure that this inrush current is always kept under control, even under very high output current variations at start-up.

In addition to its inrush current protection, the XC6602 comprises a combination of a current limiter circuit and a foldback short-circuit protection, as well as a thermal shutdown circuit that turns the N-ch driver transistor off when the junction temperature of the IC reaches 150°C.

Other functionalities of the XC6602 include an enable pin which turns the IC on and off, a CL discharge function which quickly brings the output voltage down to VSS level when entering standby mode, and an under voltage lock out (UVLO) circuit which makes sure that the voltage at the VBIAS and VIN pins are high enough to guarantee proper regulation of the output voltage.

The XC6602 is available in USP-6C package for applications that require both a small form factor and a good amount of power dissipation, in SOT-89-5 package for handling even higher power dissipations, and in SOT-26W package.