مدار مجتمع (آی سی) آی سی‌کاربرد ویژه

Product Attributes

Introduction

The MAX4923–MAX4926 overvoltage protection controllers protect low-voltage systems against highvoltage faults of up to +28V when used with a -30V pFET. When the input voltage exceeds the OVLO threshold, these devices turn off the external pFET to prevent damage to protected components. The typical overvoltage trip level is set to 7.18V (MAX4923), 6.16V (MAX4924), 5.65V (MAX4925), and 4.46V (MAX4926). When the supply drops below the UVLO threshold, the devices turn off the external pFET. IN is ESD protected to ±15KV (Human Body Model) when bypassed with a 1µF ceramic capacitor to ground. Undervoltage Lockout (UVLO) The MAX4923–MAX4926 have a fixed 2.44V (typ) UVLO level. When VIN is less than VUVLO, GATE is high and FLAG is high. Overvoltage Lockout (OVLO) The MAX4923 has a 7.18V (typ) OVLO; the MAX4924 has a 6.16V (typ) OVLO; the MAX4925 has a 5.65V (typ) OVLO; and the MAX4926 has a 4.46V (typ) OVLO. When VIN is greater than VOVLO, GATE is high and FLAG is high. FLAG Output The open-drain FLAG output is used to signal to the host system that there is a fault with the input voltage. FLAG goes high during an overvoltage or undervoltage fault. Connect a pullup resistor from FLAG to the logic 1/0 voltage of the host system. Device Operation The MAX4923–MAX4926 have an on-board state machine to control device operation. At initial power up, if VIN < VUVLO or if VIN > VOVLO, both GATE and FLAG are high. When VUVLO < VIN < VOVLO, an internal timer starts counting and the device enters its on state after a 20ms delay. At any time if VIN drops below VUVLO or above VOVLO, both GATE and FLAG transition high.

Features

• Overvoltage protection up to ±28V
• Preset 7.18V, 6.16V, 5.65V, and 4.46V typical overvoltage trip levels
• Preset 2.44V typical undervoltage trip level
• ±2.5% accurate overvoltage/undervoltage trip levels
• Low 13µA (typ) supply current
• Drives external pFET
• 20ms adapter debounce time
• Fault flag indicator
• 6-Pin (1.5mm x 1.0mm) µDFN package

Applications

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