36V Boost Controller with 3.5A Synchronous Buck Converter For Automotive Applications

The MAX20458 is an automotive grade PMIC that includes a 3.5A synchronous buck converter and an asynchronous boost controller with 2.1MHz and 400kHz options. The boost controller can be used to provide power to buck converters and keep them in regulation during cold-crank operation down to 2V battery input. The IC operates with an input voltage supply from 3.5V to 36V and can operate in dropout conditions by running at 95% duty cycle. It is intended for applications with mid- to high-power requirements that operate at a wide input voltage range, such as during automotive cold-crank or engine stop-start conditions.

High switching frequency up to 2.1MHz allows small external components, reduced output ripple, and guarantees no AM band interference. The switching frequency is fixed at 400kHz or 2.1MHz. FSYNC input programmability enables three modes for optimized performance: forced fixed-frequency operation, skip mode with ultra-low quiescent current, and phase-locked synchronization to an external clock. The spread spectrum option minimizes EMI interference.

The IC features the power-OK indicators for buck converters and undervoltage lockout for each power rail. Protection features include cycle-by-cycle current limit and thermal shutdown. The MAX20458 is specified for operation over the -40°C to +125°C automotive temperature range.

Applications

* Automotive Start-Stop System

* Distributed DC Power Systems

* Instrument Cluster

* Navigation and Radio Head Units

* Meets Stringent OEM Module Power Consumption and Performance Specifications

* 10μA Supply Current with 5V Buck On

* OUT Can Be Either 5V or 3.3V

* 30µA Supply Current with All Regulators On

* Enables Crank-Ready Designs

* Output Voltages in Regulation Through Cold Crank Down to 2V Battery Voltage

* Wide Input Supply Range from 3.5V to 36V

* EMI Reduction Features Reduce Interference with Sensitive Radio Bands without Sacrificing Wide Input Voltage Range

* 20ns (typ) Minimum On-Time Guarantees Skip-Free Operation for 3.3V Output at 2.1MHz

* Spread-Spectrum Option

* Phase-Locked Loop (PLL) Frequency Synchronization