UCC3916

UCC3916 SCSI Termpower Manager FEATURES Integrated Circuit Breaker Function Integrated 0.2 Power FET SCSI, SCSI-2, SCSI-3 Compliant 1µA ICC When Disabled Programmable On Time Accurate 1.65A Trip Current and 2.0A Max Current Fixed 3% Duty Cycle Uni-Directional Switch Thermal Shutdown DESCRIPTION The UCC3916 SCSI termpower manager provides complete power management, hot swap capability, and circuit breaker functions with minimal external components. For most applications, the only external component required to operate the device, other than supply bypassing, is a timing capacitor which sets the fault time. The current trip level is internally set at 1.65A, and the maximum current level is also internally programmed for 2A. While the output current is below the trip level of 1.65A, the internal power MOSFET is switched on at a nominal 220mΩ. When the output current exceeds the trip level but remains less than the maximum current level, the MOSFET remains switched on, but the fault timer starts charging CT. Once the fault time is reached, the circuit will shut off for a time which equates to a 3% duty cycle. Finally, when the output current reaches the maximum current level, the MOSFET transitions from a switch to a constant current source. The UCC3916 is designed for uni-directional current flow, emulating a diode in series with the power MOSFET. The UCC3916 can be put in a sleep mode, drawing only 1µA of supply current. Other features include thermal shutd...