Micro PMU with 1.2 A Buck Regulator and Two 300 mA LDOs

The ADP5040 combines one high performance buck regulator and two low dropout regulators (LDO) in a small 20-lead LFCSP to meet demanding performance and board space requirements.

The high switching frequency of the buck regulator enables the use of tiny multilayer external components and minimizes board space.

When the MODE pin is set to logic high, the buck regulator operates in forced pulse width modulation (PWM) mode. When the MODE pin is set to logic low, the buck regulator operates in PWM mode when the load is around the nominal value. When the load current falls below a predefined threshold the regulator operates in power save mode (PSM) improving the light-load efficiency. The low quiescent current, low dropout voltage, and wide input voltage range of the ADP5040 LDOs extend the battery life of portable devices. The ADP5040 LDOs maintain a power supply rejection greater than 60 dB for frequencies as high as 10 kHz while operating with a low headroom voltage.

Each regulator in the ADP5040 is activated by a high level on the respective enable pin. The output voltages of the regulators are programmed though external resistor dividers to address a variety of applications.

* Input voltage range: 2.3 V to 5.5 V

* One 1.2 A buck regulator

* Two 300 mA LDOs

* 20-lead, 4 mm × 4 mm LFCSP package

* Overcurrent and thermal protection

* Soft start

* Undervoltage lockout

* Buck key specifications

* Output voltage range: 0.8 V to 3.8 V

* Current mode topology for excellent transient response

* 3 MHz operating frequency

* Peak efficiency up to 96%

* Uses tiny multilayer inductors and capacitors

* Mode pin selects forced PWM or auto PWM/PSM modes

* 100% duty cycle low dropout mode