ADI regulators reduce component count, increase power density

According to ADI, the ADP5041 and ADP5040 regulators meet the increasing demand for greater power density by combining a 3MHz, 1.2A buck regulator and two 300mA low dropout regulators (LDOs) in a 20 lead LFCSP package. Many discrete power solutions require up to 14 components and 126mm² of board space, whereas ADI's regulators use only nine components and 50mm² of board space. ADI says the devices are suitable power management companions to mid-range fpga, microprocessor and dsp systems where core, IO and memory voltages are necessary. The ADP5041's on chip watchdog timer is designed to provide greater reliability by monitoring code execution integrity in processor based systems and resetting the processor if it fails to strobe within a preset timeout period. It incorporates a ±1.5% over temperature accuracy reset generator that can be externally programmed to monitor low voltage power supply rails. The device also has a circuit that detects a three state condition when applied to the watchdog refresh input at the WDI pin typically controlled by a processor/dsp output port. When the processor sets this port in three state mode, the watchdog refresh timer is disabled, preventing a watchdog reset to the processor. According to ADI, this feature is important when supporting processor/dsp sleep operation where the core is disabled and watchdog timer cannot be refreshed. ADI states that both regulators reduce thermal dissipation by using high efficiency switching regulators with up to 96% buck power efficiency. For low noise analogue circuit applications, the LDOs maintain a power supply rejection greater than 60dB for frequencies as high as 10kHz while operating with a low headroom voltage. The devices also provide a three rail system power supply (1.2-A buck regulator and two 300mA LDOs) with adjustable output voltages, which allows output voltages to be easily set using an external resistor divider network. The 3MHz buck regulator switching frequency allows small ceramic inductors to be used, enabling them to be quickly modified for applications with short product design schedules such as portable medical and industrial devices.