UC3725

UC1725 UC2725 UC3725 Isolated High Side FET Driver FEATURES Receives Both Power and Signal Across the Isolation Boundary 9 to 15 Volt High Level Gate Drive Under-voltage Lockout Programmable Over-current Shutdown and Restart Output Enable Function DESCRIPTION The UC1725 and its companion chip, the UC1724, provide all the necessary features to drive an isolated MOSFET transistor from a TTL input signal. A unique modulation scheme is used to transmit both power and signals across an isolation boundary with a minimum of external components. Protection circuitry, including under-voltage lockout, over-current shutdown, and gate voltage clamping provide fault protection for the MOSFET. High level gate drive is guaranteed to be greater than 9 volts and less than 15 volts under all conditions. Uses include isolated off-line full bridge and half bridge drives for driving motors, switches, and any other load requiring full electrical isolation. The UC1725 is characterized for operation over the full military temperature range of -55°C to +125°C while the UC2725 and UC3725 are characterized for -25°C to +85°C and 0°C to +70°C respectively. BLOCK DIAGRAM UDG-92051-1 1/94 UC1725 UC2725 UC3725 ABSOLUTE MAXIMUM RATINGS Supply Voltage (pin 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30V Power inputs (pins 7 & 8) . . . . . . . . . . . . . . . . . . . . . . . . . . . 30V Output current, source or sink (pin 2) DC. . . . . . . . . . . . . . . . . . . . . . . . . ...