Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters

The MAX20028 power-management integrated circuit (PMIC) is a 2.1MHz, multichannel, DC-DC converter designed for automotive applications. The device integrates three supplies in a small footprint. The device includes one high-voltage step-down controller (OUT1) designed to run directly from a car battery, and two low-voltage step-down converters (OUT2/OUT3) cascaded from OUT1. Under no-load conditions, the MAX20028 consumes only 30µA of quiescent current, making it ideal for automotive applications.

The high-voltage synchronous step-down DC-DC controller (OUT1) operates from a voltage up to 36V continuous and is protected from load-dump transients up to 42V. There is a pin-selectable frequency option of either 2.1MHz or a factory-set frequency for 1.05MHz, 525kHz, 420kHz, or 350kHz. The low-voltage, synchronous step-down DC-DC converters run directly from OUT1 and can supply output currents up to 3A. The device provides a spread-spectrum enable input (SSEN) to provide quick improvement in electromagnetic interference when needed. There is also a SYNC I/O for providing either an input to synchronize to an external clock source or an output of the internally generated clock (see the Selector Guide for the different options available). The device includes overtemperature shutdown and overcurrent limiting. The device also includes individual active-low RESET1 outputs and individual enable inputs. The individual active-low RESET1 outputs provide voltage monitoring for all output channels. The MAX20028 is available in a 32-pin (5mm x 5mm x 0.75mm) side-wettable TQFN-EP package and is specified for operation over the -40°C to +125°C automotive temperature range.Applications

* Automotive * Industrial * ADAS

* High-Efficiency Voltage DC-DC Controller Saves Power

* 3.5V to 36V Operating Supply Voltage

* Output Voltage: Pin Selectable, Fixed, or Resistor-Divider Adjustable

* 350kHz to 2.1MHz Operation

* 30µA Quiescent Current with DC-DC Controller Enabled

* Dual 2.1MHz DC-DC Converters with Integrated FETs Saves Space

* OUT2 and OUT3 Are Cascaded from OUT1, Improving Efficiency

* 3A Output Current

* 0.8V to 3.95V Output Voltage

* 25% Lower COUT2 and COUT3 Compared to the MAX16993

* Fixed or Resistor-Divider-Adjustable Output Voltage

* 180° Out-of-Phase Operation

* High Accuracy to Meet ASIL Specification

* ±1% FB Accuracy, ±2% Output-Voltage Accuracy, and ±0.5% OV/UV Accuracy

* Excellent Load-Transient Performance

* Robust for the Automotive Environment

* Current-Mode Architecture with Forced-PWM and Skip Modes of Operations

* Frequency Synchronization Input/Output Reduces System Noise

* Individual Enable Inputs and Active-Low RESET1 Outputs

* Overtemperature and Short-Circuit Protection

* AECQ-100 Qualified