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LMZ34002: Alternate part number

Vishwajit Vivek
Prodigy 160 points
Part Number: LMZ34002
Other Parts Discussed in Thread: LMZM33604, LMZM33606,

Hi,

I need a regulator that would generate negative 5 volts from positive 5 volts. Kindly suggest me a switching regulator which has a current rating of more than 2 Ampere.

  • 0
    TI__Guru 50120 points

    Hi Vishwajit,

    You can try configuring the LMZM33604 into an inverting buck boost topology to achieve the desired application of 5Vin to -5Vout @ 2A. 
    For reference, please take a look at this app note.

    Regards,

    Jimmy 

  • 0
    TI__Mastermind 19891 points
    Hello Vishwajit,

    Do you need 2A of total load current on the -5V rail or 2A of switch current rating?

    If you need 2A of load current, the current rating of the device should be at least 4A for 5V to -5V design.

    The LMZM33606 is a 3.5V to 36V Input, 6A Power Module in 10x16x4mm QFN Package.
    This device can cover a wide range of applications and will certainly work for 5V in to -5V out at 2A load. Here is an application note for the inverting application:
    www.ti.com/.../snva835.pdf

    Cheers,
    Denislav
  • 0 in reply to Denislav Petkov
    Prodigy 160 points
    Hi,
    The links given in the comment section are not opening. Kindly resend a new link.
  • 0 in reply to Denislav Petkov
    Prodigy 160 points

    A) I need a regulator that would convert 5 volts input to -5 volts output and it must carry current of 2 Ampere to 2.2 Ampere of current which is the load current. Kindly suggest me a regulator which can meet this requirement as soon as possible.

    B) Let me know whether is there any OR-ing option available to generate -5V from LMZ34002 or any regulator which has less current rating so that I can short their outputs to meet the requirement. Also mention their efficiency. 

  • 0 in reply to Vishwajit Vivek
    TI__Guru 50120 points

    Hi Vishwajit,

    The app note was recently revised to more accurately model the maximum output current limit. This is the link to the new app note. Please let me know if there is anything else that you might need.

  • 0 in reply to Jimmy Hua
    Prodigy 160 points

    Thanks. I have gone through the app note. Kindly revert back with some solution for my previous post posted on NOV 5, 2018 03:33 PM.

  • 0 in reply to Vishwajit Vivek
    TI__Guru 50120 points

    Hi Vishwajit,

    To answer your two questions on Nov.5

    1. Use the LMZM33606 device in an inverting topology following the previously linked app note to achieve 5Vin to -5Vout for 2.2A. The math checks out using the worse expected efficiency(70%) as follows:

    • D = -5 / ( -5 - 5(0.7)) = 0.58823
    • Iout = Irated * (1 - D) = 6* ( 1 - 0.58823) = 2.47A (maximum recommended continuous output current)

    2. The LMZ34002 does not have any dedicated SH pin for current sharing capabilities. Because of this the LMZ34002 cannot be configured in a way to share current larger than the maximum 0.6A shown in the efficiency graph for your 5Vin to -5Vout @ 2 - 2.2A application.

    Regards,

    Jimmy