EVALUATION KIT AVAILABLE Click here for production status of specific part numbers- MAX20457 High-Efficiency, 36V, Dual Synchronous Buck Converters (3.5A/2A) for Automotive Applications General Description Benefits and Features The MAX20457 offers two automotive grade synchronous Meets Stringent OEM Module Power Consumption buck converters with fixed frequency of either 2.1MHz or and Performance Specifications 400kHz. The two high-voltage synchronous step-down 10A Supply Current with 5V Buck On converters operate 180 out-of-phase. The IC operates 8A Supply Current with 3.3V Buck On with an input voltage supply from 3.5V to 36V and can 10A Supply Current with Both Bucks On operate in dropout conditions by running at 95% duty Enables Crank-Ready Designs cycle. It is intended for applications with mid- to high- Wide Input Supply Range from 3.5V to 36V power requirements that operate at a wide input voltage EMI Reduction Features Reduce Interference with range such as during automotive cold-crank or engine Sensitive Radio Bands without Sacrificing Wide Input stop-start conditions. Voltage Range High switching frequency up to 2.1MHz allows small 20ns (typ) Minimum On-Time Guarantees Skip- external components, reduced output ripple, and guaran- Free Operation for 3.3V Output at 2.1MHz tees no AM band interference. The switching frequency is Spread-Spectrum Option fixed at 400kHz or 2.1MHz. FSYNC input programmability Phase-Locked Loop (PLL) Frequency enables three modes for optimized performance: forced Synchronization fixed-frequency operation, skip mode with ultra-low qui- Integration and Thermally Enhanced Packages Save escent current, and phase-locked synchronization to an Board Space and Cost external clock. The spread spectrum option minimizes Two 2.1MHz Current-Mode Converters with Forced EMI interference. Fixed Frequency and Skip Modes The IC features the power-OK indicators and undervolt- Thermally Enhanced 5mm x 5mm, 28-Pin TQFN- age lockout for the buck converters. Protection features EP Package include cycle-by-cycle current limit and thermal shutdown. Protection Features Improve System Reliability The MAX20457 is specified for operation over the -40C Supply Undervoltage Lockout to +125C automotive temperature range. Overtemperature and Short-Circuit Protection Applications Automotive Start-Stop System Ordering Information appears at end of data sheet. Instrument Cluster Distributed DC Power Systems Navigation and Radio Head Units 19-100476 Rev 3 11/19MAX20457 High-Efficiency, 36V, Dual Synchronous Buck Converters (3.5A/2A) for Automotive Applications Simplified Block Diagram BUCK1 CONTROL LOGIC PGOOD1 PGOOD MAX20457 COMP THRESHOLD FB1 FEEDBACK SUPSW1 SELECT LOGIC EAMP1 BST1 INTERNAL EN1 SOFT START OUT1 BUCK1 PWM1 LX1 PWM1 GATE DRIVE CURRENT SENSE LOGIC AND SLOPE COMP BIAS LX1 EN1 CLK1 CLK1 BIAS PGND1 SPREAD SPECTRUM OSCILLATOR ON/OFF OPTION PLL/SYNC INTERNAL BIAS BIAS DETECTION LINEAR REGULATOR FSYNC FSYNC SELECT CLK 180 LOGIC PGND OUT OF PHASE EXTVCC SWITCHOVER AGND BIAS SUPSW2 CLK2 BST2 FB2 EN2 BUCK2 OUT2 GATE DRIVE BUCK2 CONTROL LOGIC LOGIC LX2 EN2 PWM2 SAME AS BUCK1 BIAS PGOOD2 CLK2 PGND2 Maxim Integrated 2 www.maximintegrated.com