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LTM2881IV-5#PBF Transceiver IC 's Inbuilt DC-DC Converter


We are using  LTM2881IV-5#PBF IC, in our Project. Output of inbuilt DC-DC Converter is zero while measuring IC's ON Pin, it is 5V. so in which conditions the inbuilt DC-DC Converter 's output becomes Zero ?

  • Hello, 

    While the ON pin is asserted, the LTM2881 should power up . 

    What are the measured voltages on the VCC and VL supply voltages? Does the VCC in particular have a clean stable power supply in the 4.5V - 5.5V range? 

    Is it possible to capture a waveform of the VCC and VISO output voltages as the ON pin is asserted from 0V to VL? This will allow us to debug the start up behavior of the device, 



  • Hi,

    VCC and VL supply voltages and ON Pins are +5V. VCC2 supply voltage is captured, which is 0V. 

  • Thanks for the response,

    We will need a bit more information to debug this issue, 

    Can you capture an oscilloscope waveform of the LTM2881 VCC2 output voltage and VCC input voltage during either of these conditions: 

    • VCC is already powered up, switch ON from 0V to VL, trigger oscilloscope on rising edge of ON signal.
    • ON = VL. Bring up VCC from 0V to 5V, trigger oscilloscope on the rising edge of VCC.  

    What external circuitry, if any, are connected to the VCC2 supply output of the LTM2881?