LM34904 Datasheet, PDF (6/9 Pages) Texas Instruments – 500mA Current Limited Power Switch

LM34904
Block Diagram
30194203
Application Hints
To turn on the PFET switch, both the ENABLE and the ACC_DET pins need to be asserted. In addition, ACC_DET needs to be
asserted no later than the rising edge of the ENABLE signal. De-assertion of either the ENABLE or the ACC_DET will result in
turned-off PFET switch and de-asserted POK signal.
To prevent a glitch in the otherwise asserted ACC_DET from keeping the FETs turned off, it is a good practice to cycle the ENABLE
following every falling edge in the ACC_DET signal. When cycling the ENABLE, make sure it stays low for at least T₃ long before
toggling back high. If ENABLE logic high level is not 1.8V, make sure ENABLE stays low for at least 1µs.
When laying out the PCB, try to keep the ENABLE and ACC_DET traces as short as possible and away from noisy traces.
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