Automotive High-Current Step-Down Converter with USB Protection/Host Charger Adapter Emulator

Industry's First USB Data Protection Switch that Integrates a High-Voltage, Feedback-Adjustable DC-DC Converter


The MAX16984 combines a 5V automotive-grade step-down converter capable of driving up to 2.5A, a USB host charger adapter emulator, and USB protection switches for automotive USB host applications. The USB protection switches provide high-ESD, short-circuit protection and feature integrated host-charger port-detection circuitry adhering to the USB 2.0 Battery Charging Specification BC1.2 battery charging specification and Chinese Telecommunication Industry Standard YD/T 1591-2009. They also include circuitry for iPod®/iPhone® 1.0A and iPad® 2.1A dedicated charging modes. The HVD+ and HVD- ESD protection features include protection to ±15kV Air/±8kV Contact on the HVD+ and HVD- outputs to the IEC 61000-4-2 model and 330Ω, 330pF ESD model.

The high-efficiency step-down DC-DC converter operates from a voltage up to 28V and is protected from load dump transients up to 42V. The device is optimized for high-frequency operation and includes resistor-programmable frequency selection from 220kHz to 2.2MHz to allow optimization of efficiency, noise, and board space based on application requirements. The converter has an internal high-side n-channel switch and uses a low forward-drop freewheeling Schottky diode for rectification. There is a small low-side n-channel switch to maintain fixed frequency under light loads. For lower quiescent current operation requirements, the low-side n-channel switch can be disabled to allow skip mode operation under light loads. The converter can deliver up to 2.1A of continuous current at 105°C. The MAX16984S has an integrated spread-spectrum oscillator to improve EMI performance.

The MAX16984 also includes a USB load current-sense amplifier and configurable feedback adjustment circuit designed to provide automatic USB voltage adjustment to compensate for voltage drops in captive cables associated with automotive applications. The MAX16984 limits the USB load current using both a fixed internal peak current threshold of the DC-DC converter and a user-configurable external USB load current-sense amplifier threshold.
MAX16984: Typical Operating Circuit MAX16984: Typical Operating Circuit Enlarge+

Key Features

  • Integrated DC-DC and USB Host Charge Emulator Enables 1-Chip Solution Directly from Car Battery to Portable Device
    • 4.5V to 28V (42V Load Dump) Operating Voltage
    • 5V, 2.5A Output Current Capability
    • Low-Q Current Skip and Shutdown Modes
    • Soft-Start Reduces Inrush Current
  • Low-Noise Features Prevent Interference with AM Band and Portable Devices
    • Fixed-Frequency 220kHz to 2.2MHz Operation
    • Forced-PWM Option at No Load
    • Spread Spectrum for EMI Reduction
    • SYNC Input for Frequency Parking
  • Optimal USB Power and Communication for Portable Devices
    • User-Adjustable Voltage Gain Adjusts Output Between 5V and 6.15V for Cable Compensation
    • ±3% Accuracy User-Adjustable USB Current Limit
    • 4Ω USB 2.0 480Mbps/12Mbps Data Switches
    • Integrated iPod/iPhone/iPad Charge-Detection Termination Resistors
    • Supports USB BC1.2 Charging Downstream Port(CDP) and Dedicated Charging Port (DCP) Modes
    • Supports Chinese Telecommunication Industry Standard YD/T 1591-2009
    • Compatible with USB On-the-Go Specification
    • High-Speed Pass-Through Mode
  • Robust Design Keeps Vehicle System and Portable Devices Safe in Automotive Environment
    • Short-to-Battery Protection on DC-DC Converter
    • Short-to-Battery Protection on USB Pins
    • ±25kV Air/±8kV Contact ISO 10605
    • ±15kV Air/±8kV Contact IEC 61000-4-2
    • ±15kV Air/±8kV Contact (330Ω, 330pF)
    • Fault-Indication Active-Low, Open-Drain Output
    • Reduced Inrush Current with Soft-Start
    • Overtemperature Protection
    • -40°C to +125°C Operating Temperature Range
    • 28-Pin, 5mm x 5mm, TQFN and Side-Wettable QFND Packages


  • Automotive Connectivity
  • Automotive Radio and Navigation
  • Dedicated USB Power Charger
  • Telematics
  • USB Port for Host and Hub Applications
Part Number VIN
Preset VOUT
Output Adjust. Method IOUT1
Switch Type Synchronous Switching DC-DC Outputs Oper. Freq.
min max min max max
MAX16984  4.5 28 5.05 6.3 5.05
2.5 Internal Yes 1 2200
See All Step-Down Switching Regulators (312)

Part Number Supported Charging Configurations Supported USB Battery Charging Specification Charging Modes Current Limit Switch Control CDP Emulation Remote Wake-Up Support VBUS Reset Time
Package/Pins Oper. Temp.
Apple 1.0A
Apple 2.1A
China YD/T 1591-2009
USB Dedicated Charger
Auto Detection
Auto Detection with Apple 1A
Auto Detection with Apple 2A
CDP Emulation Pass-Through
Forced Dedicated Charger
CEN Yes No 0.016
-40 to +125
See All USB Host Adapter Emulator (20)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

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