This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMG1210: Can I use only the upper side as an driver amplifier?

Part Number: LMG1210

Hi Experts,

Our customer wants to use only a half part of the LMG1210 as a driver amplifier. Is it possible to connect HS and VSS together to the GND? Thus the customer will only use the upper side as a driver amplifier and HO is the output of the driver. Please see the picture below.

Another inquiry, if  the customer only use the lower side, shall he need to connect HS to GND aiming to avoid any influence from the circuits or just leave HS pad floating?

Kind regards, 

Marvin

  • Hi Marvin,

    Using the upper side as an amplifier should work as described as long as the device is in HI/LI mode rather that PWM. Also it will require HB to be connected to VDD.

    If using LO, HS should be connected to ground as you have mentioned.

    Thanks,

    Daniel W

  • Hi Daniel, 

    Thank you for your prompt response. Additional info was asked by the customer.

    "Could I add another question, if I only use the lower side as a driver, should the HS pad be connected to GND aiming to avoid influence from circuits or be left floating i.e. be open without connecting?"

    Kind regards, 

    Marvin

  • Hi Marvin,

    If using LO only, HS and its pad should be connected to GND

    Thanks,

    Daniel W

  • Hi Daniel, 

    Thank you for the information. Additional info is requested and your response is highly appreciated.

    "My input signal is a Pulse signal generated by a crystal oscillator. I want to use LMG1210 as a driver of a switch mode amplifier which works in Class E/F mode. I only use a half part of the LMG1210, and I need to tune the dead time to get the desired duty cycle by which to optimize the amplifier's performance. Either the upper side or the lower side is ok for me if only it can work under my requirement.

    If I understand you correctly, do you mean that I have to make LMG1210 work under the HI/LI mode if I only use half part of it, and under this mode I can't adjust the dead time by DLH and DHL pins, so the LMG1210 is not able to achieve my design requirement? 

    I notice that the maximum deadtime is 20ns with a minimum of 20Kohm resistor. Does it mean even though I decrease the resistor's value less than 20Kohm, I can't get a deadtime more than 20ns? or the resistor can't be less than 20kohm to avoid something unexpected?"

    Kind regards, 

    Marvin

  • Hi Marvin,

    Operation of the device is not guaranteed outside of the datasheet guidelines, in this case, 20kohm minimum dead time resistance. The maximum dead time spec (20ns typ) is achievable with 20kohm resistance.

    In the case of using only one side of the driver while in PWM mode, it is important to note that the other side will still switch, and the output will need to be floating, not grounded.

    HI/LI would just provide better operation if possible since the unused driver will not be switching.

    Thanks,

    Daniel W