For use in sub-power rails in server applications, the 5A eFuses are in a compact 3mm x 3mm DFN package. They are constructed with the company’s co-packaging technology, combining an IC with protection features and a high SOA (safe operating area) trench MOSFET.  

The back-to-back MOSFETs isolate the load from the input bus when the eFuse is switched off.

The high-reliability requirements for server products means that all critical power rails are monitored and protected by an eFuse device to protect the main power bus from interruption due to abnormal load under fault conditions. The eFuse continuously monitors the current flowing through the power switch.  If the current is higher than the set limit, the switch will limit the current to the maximum allowed.  If the high current load persists, the switch will eventually turn off, protecting downstream loads from damage.

The series comprises the AOZ18101DI-01, AOZ18101DI-02, AOZ18101DI-03 and AOZ18101DI-04. The AOZ18101DI-01and AOZ18101DI-02 integrate true reverse current blocking (TRCB) for the fault conditions that the power rail at Vout is higher than the main bus at Vin, allowing no reverse current. Control for the external blocking FET is also available for designs already in production - a drop-in replacement to existing eFuse products which requires external FETs to implement the TRCB feature. 

For loads with high inductive kickback such as hard disc drive and server fans, the AOZ18101DI-03 and AOZ18101DI-04 has the TRCB feature disabled to avoid shut down of the input power bus due to a reverse current.  All devices feature start up SOA management, programmable over-current protection, under-voltage lock-out, over-voltage clamp, thermal shutdown protection and true reverse current clocking (AOZ18101DI-01 and AOZ18101DI-02) contribute to a glitch-free power-up of the system or hot plug into the 12V backplane, says the company.

Operating range is 3.5 to 14V, with 22V absolute maximum rating.

The eFuses are available in production quantities now with a lead time of 14 weeks.