مدار مجتمع (آی سی) آی سی‌کاربرد ویژه

Product Attributes

Introduction

The MAX4843–MAX4846 overvoltage protection controllers protect low-voltage systems against high-voltage faults of up to 28V. When the input voltage exceeds the overvoltage threshold, these devices turn off a low-cost, external n-channel FET(s) to prevent damage to the protected components. An internal charge pump eliminates the need for external capacitors and drives the FET gate for a simple, robust solution. The overvoltage trip level is set to 7.4V (MAX4843), 6.35V (MAX4844), 5.8V (MAX4845), or 4.65V (MAX4846). When the input voltage drops below the undervoltage lockout (UVLO) threshold, the devices enter a low standby current mode (10μA). The MAX4843/MAX4844/MAX4845 have a UVLO threshold of 4.15V, the MAX4845C/MAX4845D have a UVLO threshold of 2.2V, and the MAX4846 has a UVLO threshold of 2.5V. In addition to the single FET configuration, the devices can be configured with back-toback external FETs to prevent currents from being back-driven into the adapter. An additional feature includes a ±15KV ESD-protected input when bypassed with a 1μF capacitor to ground. All devices are offered in small 6-pin μADFN (1.5mm x 1.0mm) and 6-pin ultra-thin LGA (MAX4845 and MAX4846 only) (1.5mm x 1.0mm) packages and are specified for operation over the -40℃ to +85℃ temperature range.

The MAX4843–MAX4846 provide up to 28V overvoltage protection for low-voltage systems. When the input voltage exceeds the overvoltage trip level, the MAX4843–MAX4846 turn off a low-cost external n-channel FET(s) to prevent damage to the protected components. An internal charge pump (see the Functional Diagram) drives the FET gate for a simple, robust solution. On power-up, the device waits for 50ms before driving GATE high. The open-drain FLAG output is kept at high impedance for an additional 50ms after GATE goes high before deasserting. The FLAG output asserts high immediately to an overvoltage fault.

Features

• Overvoltage Protection Up to 28V
• Preset 7.4V, 6.35V, 5.8V, or 4.65V Overvoltage Trip Level
• Low (10μA) Undervoltage Lockout Standby Current
• Drives Low-Cost nMOSFET
• Internal 50ms Startup Delay
• Internal Charge Pump
• Overvoltage Fault FLAG Indicator
• 6-Pin (1.5mm x 1.0mm) μDFN Package

Applications

• Cell Phones
• Digital Still Cameras
• PDAs and Palmtop Devices
• MP3 Players