MIC2012

Features:

• Compliant to USB power distribution specifications
• Two completely independent switches
• Integrated switching matrix supports ACPI S0/S3 state transitions without external FET circuits
• Make-before-break switching ensures glitch-free transitions
• No back-feed of auxiliary supply onto main supply during standby mode
• Bi-level current-limit preserves auxiliary supply voltage regulation in standby mode
• Thermally isolated channels
• Thermal shutdown protection
• Fault status outputs with filter prevents false assertions during hot-plug events
• Latched thermal shutdown options with auto-reset (MIC2072)
• Undervoltage lockout


Application

• Desktop PCs
• Notebook PCs
• Notebook Docking stations
• LAN Servers
• PC Motherboards


Pinout




Specifications

Supply Voltage (V_IN, V_MAIN, V_AUX) ................. 0.3V to 6V
EN1, EN2, S3# Input Pins ............................. 0.3V to 6V
FAULT#, OUT1, OUT2 Output Pins ................ 0.3V to 6V
FAULT Output Current ..............................................25mA
ESD Rating, Note 3 ..................................................... 2kV


Description

The MIC2012 is a dual channel USB power switch designed to support the power distribution requirements for USB Wakeup from the ACPI S3 state. The MIC2012 will directly switch its two outputs between a 5V main supply and a 5V auxiliary supply normally provided in ATX style power supplies.

The MIC2012 will adjust its current-limit threshold according to the ACPI state it is in. In the normal active S0 state the current-limit is set at 500mA minimum per channel satisfying the USB continuous output current specification. In the S3 state the current-limit of MIC2012 can be reduced to only 100mA per channel to minimize the current that is supplied by the auxiliary supply thereby ensuring that voltage regulation is maintained even during fault conditions.

The MIC2012 provides make-before-break switching to ensure glitch-free transitions between the S3 and S0 states.
Each channel is also thermally isolated from the other so that a fault in one channel does not effect the other. FAULT status output signals are also provided indicating overcurrent and thermal shutdown conditions.

The MIC2072 option latches the output off upon detecting an overcurrent condition for more than 5ms minimum. The
output of MIC2012 can be reset by either toggling the EN inputs of the MIC2072-1, -2 or by removing the load. Latching the output off provides a circuit breaker mode of operation which reduces power consumption during fault conditions.