General Instructions
The ADM1070 is a negative voltage hot-swap controller allowing boards to be safely inserted and removed from the field - 48V backplane. Partially implemented by providing robust current limit protection from transient and nontransient short circuits and overvoltage and undervoltage conditions. "The ADM1070 is typically limited from negative voltages -80 V and can tolerate transient voltages of -200 V inrush current limiting by controlling the gate drive of an external N-channel FET with a programmable value. The current limit can be controlled by the sense resistor's Select, RSENSE. Controlled by inrush current is by an on-chip timer that allows maximum current to flow using PWM, only 3% of the time. An auto-restart occurs after a current-limit timeout. After 7 consecutive autorestarts, A fault will be latched, part of the entry results in shutdown, and the external FETs are disabled until power is reset. The ADM1070 also has single-pin undervoltage and overvoltage detection. The FET is turned off if a nontransient voltage falls below the undervoltage threshold, typically is -36 V, or the detected overvoltage threshold is larger, typically -77 V, UV/OV pin. The operating voltage window of the ADM1070 is programmable and is determined by the ratio of R1/R2. Undervoltage and overvoltage detection times Filtering and current limit are programmable through the TIMER pin. An external capacitor connected between the TIMER pin and VEE determines the undervoltage/overvoltage time filter and timeout during current limit. If the pin is connected to VEE, the time filter The timer timeout value and current limit revert to default numbers. The ADM1070 is built with minimal power dissipation in BiCMOS technology. The part is available in a small 6-pin SOT-23 package.