RE029

RE029 is a dual mode Low Drop Out (LDO) voltage regulator macrocell with a fixed1.8V output voltage, rated for loads up to 80 mA in full power mode and 5 mA in lowpower mode. (Both modes of RE029 can be selected by the LP8 signal.) It is designed to beintegrated with other analog cells, digital logic, microcontrollers, DSP cores and mem-ory blocks into system-on-chip products.

The circuit RE029 consists of a PMOS pass device, an error amplifier and a feedback resis-tive network, sized to achieve the required closed loop gain. These blocks make upthe regulating loop. An over-current and short circuit protection circuit RE029 has beenincluded to limit the output current delivered by the regulator, thus avoiding destructionin case of a short circuit.

An external reference voltage VBG (bandgap voltage)RE029  is necessary for correct function-ality. The target reference voltage is 1.231V delivered, for example, by BG019. Doublepads on the supply voltage VBAT1B/VBAT1BB and output voltage VMLVA/VMLVAA are used toreduce the total output resistance. Current reference ofRE029 is generated inside the cellthrough a circuit supplied by a 2.5V ± 0.1V of regulated input voltage on VSAUVC.

Remote sense terminal VMLVS provides regulation of the load by connecting it to theoutput terminal near a critical point to improve performance of the regulator (e.g., con-necting RE029 to the package pin by double-bonding, thus avoiding the bonding resistanceinfluence). A ceramic capacitor RE029 of 2.2 µF connected from VMLVA/VMLVAA to ground isneeded as external compensation.