Called MAX77540, it comes in a 2.5 x 2.3mm 30bump wafer-level package and peaks at 94% efficiency when converting 7.4V to 3.3V.
Outputs can be set between 500mV to 5.2V, and the two halves can be paralleled to produce a single 6A output.
“Default power on configuration only requires two external resistors, and an I2C interface allows further control for advanced power management techniques,” according to the company. “External frequency tracking and spread spectrum modulation provide low EMI power conversions for data sensing and processing equipment.”
Inside is a proprietary adaptive constant on-time current-mode control scheme which “provides fast response to load transients, inherent compensation to input voltage variation and stable performance at low duty cycles”, said ADI.
The top mosfet is controlled by an on-time generator circuit which calculates on-time based on the input voltage, output voltage and the target switching frequency (FSW1). A PWM comparator regulates Vout modulating off-time. The comparator’s positive input is a voltage proportional to the actual output voltage error, and its negative input is a voltage proportional to the inductor current sensed through the bottom mosfet. The comparator begins an on-time when the error voltage becomes higher than the current-sense signal.
A phase-locked loop stabilises the switching frequency and controls phase spacing – splitting the two converters 180° when they are used to create a single output. At low power there is a choice of two efficiency-boosting modes. Operation is at one of three nominals: 500kHz, 1MHz or 1.6MHz.
The chip has an alternative low-voltage input (ALT_IN. 5.5Vmax) that can be used to power the internal system linear regulators from a voltage lower than the main input source to decrease internal power waste. This input can, for example, be connected to on of the dc-dc converter outputs. Automatic reversion re-connects the main input if the secondary source is not present.
Applications is expected in augmented and virtual reality head gear, land mobile radios and digital single-lens reflex cameras.
There is an evaluation board: MAX77540EVKIT.