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ALM2402-Q1: Dual Supply & EPAD Connection

Mike Adams2
Prodigy 30 points

Part Number: ALM2402-Q1
Other Parts Discussed in Thread: ALM2402F-Q1, , ALM2403-Q1

Tool/software:

The ALM2402Q1 op-amp is to be placed in a circuit with dual supply configuration.  There are two pins labeled as ground, and not V- like usual amps, which are to be connected to the negative rail.  The EPAD is noted, "It is recommended to connect the Exposed Pad to ground for best thermal performance. Must not be connected to any other pin than ground. However, it can be left floating.".  What is the required connection of the EPAD, i.e. 1. attach to negative supply the same as the ground pins 2. Attach to ground separate from the ground pins, 3. attach to copper for thermal dissipation but keep no electrical connection.

  • 0
    TI__Mastermind 18386 points

    Hi Mike,

    Good question,

    This device uses slightly older terminology for this pin, and your understanding is correct that "GND" can be V- in a dual supply configuration. 

    Since these devices tend to often be connected in single supply this also contributes to the verbiage used in the data sheet. 

    In your use-case we can connect the thermal pad to V- or float. If you go the route of electrically floating the pin, I would still use a copper pour to help pull away heat during high current operation. 

    If using dual supply, just remember that OTF/SHDN pin will now reference the V- supply. Due to V- being negative, it may be necessary to level shift if using something like an MCU to interface with this pin. 

    In some scenarios, ALM2402-Q1 is the better choice, but I also wanted to let you know we also have newer product offerings being the ALM2403-Q1 (wider supply range, more BW, more SR, low IIB) and ALM2402F-Q1 (similar to ALM2402 but with higher slew rate and BW). 

    These devices are all somewhat P2P with some slight differences. 

    Please reach out if I can offer any assistance with the design process. 

    Thanks,

    Jacob