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36V Dual 3.5A/2A Synchronous Buck Converters for Automotive Applications

Low Iq Dual Buck Offering High Integration and Low BOM Cost for Automotive Applications

Product Details

The MAX20457 offers two automotive-grade synchronous buck converters with fixed frequency of either 2.1MHz or 400kHz. The two high-voltage synchronous step-down converters operate 180 degrees out of phase. 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 power-OK indicators and undervoltage lockout for the buck converters. Protection features include cycle-by-cycle current limit and thermal shutdown. The MAX20457 is specified for operation over the -40°C to +125°C automotive temperature range.

Key Features

  • Meets Stringent OEM Module Power Consumption and Performance Specifications
    • 10µA Supply Current with 5V Buck On
    • 8µA Supply Current with 3.3V Buck On
    • 10µA Supply Current with Both Bucks On
  • Enables Crank-Ready Designs
    • 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
  • Integration and Thermally Enhanced Packages Save Board Space and Cost
    • Two 2.1MHz Current-Mode Converters with Forced Fixed Frequency and Skip Modes
    • Thermally Enhanced 5mm x 5mm, 28-Pin TQFN-EP Package
  • Protection Features Improve System Reliability
    • Supply Undervoltage Lockout
    • Overtemperature and Short-Circuit Protection

Applications/Uses

  • Automotive Start-Stop System
  • Instrument Cluster
  • Navigation and Radio Head Units
  • Telematics Applications
Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 2.05
VIN (V) (max) 36
VOUT1 (V) (min) 0
VOUT1 (V) (max) 15
IOUT1 (A) (max) 3.5
Switch Type Internal
Preset VOUT (V) 5V & 3.3V
Output Adjust. Method Preset or Adj
Synchronous Switching? Yes
Power Good Signal Yes
# DC-DC Outputs 2
Switching Frequency (kHz) 2100
Design Tools EE-Sim
Package/Pins TQFN/28
Budgetary
Price (See Notes)
$1.64 @1k
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Technical Docs

Design & Development

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Description

The MAX20457 evaluation kit (EV kit) is a fully assembled and tested application circuit that simplifies the evaluation of the MAX20457 2.1MHz dual buck converters. All installed components are rated for the automotive temperature range. Various test points and jumpers are included for evaluation.

The standard EV kit comes with the MAX20457ATIE/VY+ installed (5V, 3.3V, 2.1MHz) and can also be used to evaluate other MAX20457 variants with minimal component changes shown in the MAX20457 EV Kit Bill of Materials.

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Features

  • Dual High-Voltage Step-Down Converters with Integrated Power FETs to Minimize Board-Area Occupancy
  • 3.5V to 40V Input Supply Range
  • Buck1 Provides 5V Output up to 3.5A Output Current
  • Buck2 Provides 3.3V Output up to 2A Output Current
  • Buck Output Voltages Adjustable Between 1V and 4V using External Resistors
  • ±2% Output Voltage Accuracy for Buck Converters
  • Selectable Buck2 Input Source
  • Frequency-Synchronization Input
  • Independent Enable Inputs
  • Voltage-Monitoring PGOOD Outputs
  • Jumpers and Test Points on Key Nodes for Simplified Evaluation
  • Proven PCB Layout
  • Fully Assembled and Tested

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Tools & Models

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Parameters

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 2.05
VIN (V) (max) 36
VOUT1 (V) (min) 0
VOUT1 (V) (max) 15
IOUT1 (A) (max) 3.5
Switch Type Internal
Preset VOUT (V) 5V & 3.3V
Output Adjust. Method Preset or Adj
Synchronous Switching? Yes
Power Good Signal Yes
# DC-DC Outputs 2
Switching Frequency (kHz) 2100
Design Tools EE-Sim
Package/Pins TQFN/28
Budgetary
Price (See Notes)
$1.64 @1k

Key Features

  • Meets Stringent OEM Module Power Consumption and Performance Specifications
    • 10µA Supply Current with 5V Buck On
    • 8µA Supply Current with 3.3V Buck On
    • 10µA Supply Current with Both Bucks On
  • Enables Crank-Ready Designs
    • 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
  • Integration and Thermally Enhanced Packages Save Board Space and Cost
    • Two 2.1MHz Current-Mode Converters with Forced Fixed Frequency and Skip Modes
    • Thermally Enhanced 5mm x 5mm, 28-Pin TQFN-EP Package
  • Protection Features Improve System Reliability
    • Supply Undervoltage Lockout
    • Overtemperature and Short-Circuit Protection

Applications/Uses

  • Automotive Start-Stop System
  • Instrument Cluster
  • Navigation and Radio Head Units
  • Telematics Applications

Description

The MAX20457 offers two automotive-grade synchronous buck converters with fixed frequency of either 2.1MHz or 400kHz. The two high-voltage synchronous step-down converters operate 180 degrees out of phase. 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 power-OK indicators and undervoltage lockout for the buck converters. Protection features include cycle-by-cycle current limit and thermal shutdown. The MAX20457 is specified for operation over the -40°C to +125°C automotive temperature range.

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal