Our customer is using STEF01 e-fuse in a system with 24V input at VCC. See schematic below. Without any load in parallel to C25 they get around 23V at the output. But as soon as they put any charge (e.g. 10Kohm resistor) at VOUT, output voltage goes down to lower than 2V (!).
Customer has tried several different configurations of the STEF01, but did not figure out what is causing the problem.
NOTE: This question and answer originated from a customer support case which was handled by us. We regularly review support cases and add any helpful ones here for all to benefit from.
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Accepted Solutions
In interaction with customer we also checked the PCB layout and finally identified the root cause: the “exposed pad�? was not connected. In fact, the exposed pad is internally connected to the power element drain and essential to proper power and thermal dissipation of the device.
Therefore it is absolutely mandatory to connect the input pins and exposed pad of the STEF01, see datasheet.
In interaction with customer we also checked the PCB layout and finally identified the root cause: the “exposed pad�? was not connected. In fact, the exposed pad is internally connected to the power element drain and essential to proper power and thermal dissipation of the device.
Therefore it is absolutely mandatory to connect the input pins and exposed pad of the STEF01, see datasheet.
