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TS5A3359: Right switch for MSP430 fuse blow

Part Number: TS5A3359


I found that TS5A3359 in my case can be right part for blowing MSP430 fuse, but have some questions.

In device absolute maximum ratings there is 6.5 VCC max, but it is not clear to me if device can switch 6.5V (Analog voltage) on VNO and VCOM? Or absolute maximum analog voltage is 5.5V?

For fuse blow 6V 100mA during 1ms is used. Out of this period (99.9% of life time) device will be on 4.5V VCC.

Also want to know real benefit from leaving device off (VCC=GND), except current consumption.

  • Hi Zrno,

    The TS5A3359 can switch voltages up to the VCC voltage level and the absolute max for the VCC pin is 6.5V. This means the NO/COM pins can support up to 6.5V without damaging the device. TI recommends that the VCC be kept at 5.5V which allows for 5.5V switching signals but voltages up to the absolute max of 6.5V will not damage the device.

    The Isolation in Power-Down Mode, VCC = 0 feature eliminates the need for power sequencing solutions, prevents data from being transmitted unintentionally, and protects the system from damage on top of reduced current consumption you mentioned. We have a tech note and a TI precision labs video that go into more detail on the subject. Please note the feature may also be referred to as powered off protection in the linked content.


  • Hi,

    Absolute max ratings are clear now. Here is how switch should be used in my design...

    VDD will be connected to COM. NOx will be connected to LVC clock signal 1.8 - 3.6V up to 10MHz. When switch is disabled (IN1=IN2=0), LVC clock signal is active. When switch is enabled, LVC clock signal is disabled (Hi-Z). I see in datasheet that CNO(OFF) is 18pF with VCC=5V. I am looking for minimum switch (IN1=IN2=0)  impact on clock signal connected to NO pins, off isolation, crosstalk, whatever. There are 6 MSP430 devices, so 2 TSA5A3359 will be used. Some of 6 can be active or not. Some clock lines can be used, some not, at the same time. If clock line is not used it is pulled up with 100k to 1.8 - 3.6V (IN1=IN2=0). Do you see any problems in this design?

    BTW, in datasheet there is 2.4V needed on IN to switch it on with 5.5 VDD. In TINA 2V with 6.1 VDD are enough. What is the real value for switch on with 6.1 VDD?


  • Hi Zrno,

    From the picture above, the schematic looks good. A general recommendation is to tie the unused channels (NO0, NO1) to ground through a 50 ohm resistor. For the IN logic level, it is recommended to follow the datasheet value. The model is a close approximation of the device but not always exact across the entire operating range for a given parameter.