Description

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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/iPhone1.0A and iPad2.1A 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.