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4.5V to 36V, 1A, High-Efficiency, Synchronous Step-Down DC-DC Converter

High-Efficiency, High-Voltage, Synchronous Step-Down DC-DC Converter with Integrated MOSFETs

Product Details

Key Features

Simplified Block Diagram

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Sampling:
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Key Features

  • Reduces External Components and Total Cost
    • No Schottky—Synchronous Operation
    • Internal Control Loop Compensation
    • Internal Soft-Start
    • All Ceramic Capacitors, Ultra-Compact Layout
  • Reduces Number of DC-DC Regulators to Stock
    • Wide 4.5V to 36V Input Voltage Range
    • Adjustable Output from 0.9V up to 89% of VIN
    • Delivers Up to 1A Load Current
  • High Efficiency
    • 90% Full-Load Efficiency (VIN = 24V, VOUT = 5V, IOUT = 1A)
    • 2.2μA (typ) Shutdown Current
    • High Light-Load Efficiency with PFM Mode (MAX17645D)
  • Flexible Design
    • Programmable EN/UVLO Threshold
    • Monotonic Startup into Prebiased Output
    • Open-Drain Output (Actiive-Low RESET) for Output Status Monitoring
  • Robust Operation
    • Built-In Hiccup Mode Overload Protection
    • Overtemperature Protection
    • CISPR32 Class B Compliant
    • Wide -40°C to +125°C Ambient Operating Temperature/-40°C to +150°C Junction Temperature

Applications/Uses

  • Factory Automation
  • Aftermarket Market Automation
  • General Point of Load

Description

The MAX17645 is a high-efficiency, high voltage, synchronous step-down DC-DC converter with integrated MOSFETs, operates over a 4.5V to 36V input. It can deliver up to 1A load current. The MAX17645 operates at 650kHz switching frequency. The MAX17645B operates in pulse-width modulation (PWM) mode at all loads. The MAX17645D operates in pulse-frequency modulation (PFM) mode at light loads. The output voltage is programmable from 0.9V up to 89% of VIN. Built-in control loop compensation across the output voltage range eliminates the need for external compensation components. The feedback voltage regulation accuracy over -40°C to +125°C is ±1.1%.

The device features a peak-current-mode control architecture. In this architecture, while operating in PWM mode the part sets the duty cycle using a transconductance error amplifier, a PWM comparator, a high-side current-sense amplifier, and a slope-compensation generator. At each rising edge of the clock, the high-side MOSFET turns on and remains on until either the appropriate or maximum duty cycle is reached, or the peak current limit is detected. During the high-side MOSFET’s on-time, the inductor current ramps up. During the rest of the switching cycle, the high-side MOSFET remains off and the low-side MOSFET remains on, inductor current ramps down. An appropriate dead time is implemented between the high-side and low-side state transitions to avoid cross conduction.

A fixed soft-start time of 3.15ms (typ) allows users to reduce input inrush current. The device also features an enable/undervoltage lockout pin (EN/UVLO) that allows the user to turn on the part at the desired input-voltage level. An open-drain active-low RESET feature provides a power-good signal to the system upon achieving successful regulation of the output voltage.

Simplified Block Diagram

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 .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.