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TS5A3159A: Excess current draw

Part Number: TS5A3159A

Hi Team, 

Working on the TS5A3159A. We did an isolated test on TS5A3159A since it is used in many designs and it keeps coming back with the following issues:

  • Select input is digital 5v tolerant: it can go above VCC up to 5v, but going below VCC will cause excess current (from VCC). Excess current starts showing up beyond 0.2~0.3v divergence from GND/VCC.
  • NO/NC channels can have any analog voltage below VCC. After going 0.2~0.3v above VCC, internal clamping diodes will start draining NO/NC voltages into VCC.

Our application has a 2.8V drive on the control line and ~4.2V supply voltage and would need the DSBGA package. 

The attached spreadsheet shows the measured current draws in the common earth return for 3 analogue switches. You can clearly see that as the Vin voltage starts to deviate from the power supply voltage that the current draw by the device deviates hugely from what the datasheet says it should be.

Regards,

RJ

anlogue switch currents.xlsx

  • Hi RJ,

    This is not excessive current draw - this is how the switch functions. We spec supply current at Vin = VDD because that is the operational point which has the smallest current draw (nA range). However as the control voltage begins to deviate - this control circuitry will begin to draw more current. This is because for this device when the logic circuits are biased at VDD or GND the impedance to VDD or GND is very high. As the control voltage begins to deviate the logic circuit will essentially become a resistor divider from VDD to GND. 

    When using this device within the proper threshold ranges (Supply = 4.2V; Threshold >= 2.4) there won't be damage to the Mux and the enabled switch will work as normal - at the cost of a higher power consumption. At uA currents there is no concern with how the switch is functioning.

    That being said is there a specific power budget that the customer is trying to hit that this is preventing them from reaching? If you can share a power budget I would be happy to see if we have parts that will be better suited for the application condtions.

    Please let me know!

    Best,

    Parker Dodson