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+/-10V buffer amplifier recommendation

shivaraj r
Prodigy 160 points

Other Parts Discussed in Thread: OPA994, OPA2544, TLV9034

 Hi     Input +/- 10V driving  below 10mA Current. i need buffer output same voltage +/-10v  i need current 50mA each channel drive output Required.

Please suggest device or circuit Reference this is for signal condition circuit

  • 0
    Guru 320660 points

    Why are you saying "each channel"? How many channels are there?

    What power supplies are available?

    The OPA994 should work with ±12 V supplies.

  • 0 in reply to Clemens Ladisch
    Prodigy 160 points

    8 signal condition inputs driving from AIO Card -10v to + 10v output same out i need output but current 50mA

    15v and 28 V i have 12v also ok

  • 0 in reply to shivaraj r
    Guru 320660 points

    In theory, the TLV9034/TLV9534/TLV9634 (they have different speeds) can do this, but with such a high output current, you might get power dissipation problems. You might need to use separate packages (TLV9x32/TLV9x31) that can be better cooled. If that does not help, the OPA2544 has a TO-220 package.

  • 0 in reply to Clemens Ladisch
    TI__Mastermind 22882 points

    Hello Shivaraj, 

    There are many answers to this question since it is open ended. I will explain the needed relationships and you may make the best decision. 

    If this is a DC application (no frequency involved), the op amp does not need large bandwidth (>5MHz). If there is a frequency component, I recommend an op amp with BW 10x the largest frequency of the application. 

    Large output current requires heat dissipation usually in terms of a thermal pad. 

    Since the input and output is ±, this requires the op amp be placed in dual supply.

    Since there are 8 signal condition inputs, often times it is easier to use 2 quad devices but not required. May use 8 single channel devices, or 4 dual channel devices.

    Depending on the power supplies available, rail-to-rail I/O may be required.

    For the buffer design, we have an existing circuit here from our reference analog designs: Buffer (follower) circuit

    I have created a solution for you but feel free to tweak it around as you see fit: 

    I suggest you use the OPA4990IRTER, it is 4 channel high voltage general purpose op amp that has a thermal pad: 

    Each channel may be used in the following configuration: 

    Since you said you have a 28V rail available this may be split into ±14V to provide ample headroom for a ±10V buffer. 
    High output current drive degrades the max output the op amp may provide, Figure 6-14 and Figure 6-15 accurately display this. 

    A safe estimate is to expect 2V from each rail to be limited. This means the application has ±12V of usability, which is ok for the expected ±10V. 
    Here is the TINA sim I used: 10V_buffer.TSC

    All the best,
    Carolina