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# TPS57140-EP: How do Io, Iout, and Iout max differ?

Part Number: TPS57140-EP

In section 8.2.2.2 of the datasheet the minimum inductance is calculated using Io, how does this value differ from Iout and Iout max. Additionally, in the design example listed the maximum output current is stated as 1.5A, is this the value that should be used wherever Iout max is stated based on the absolute max of the chip or the absolute max of the circuit that is being designed. For example, if I am designing a circuit with a worst case current draw of 0.5A, is that Iout max?

• Hello,

These can essentially be used interchangeably. For your own design, insert your own worst case output current value (0.5A) for calculating things like the minimum inductance value.

Regards,

Harrison Overturf

• Hi Harrison,

If the variables are interchangeable, then why were the variables differentiated?

• Hi Ian,

Let me discuss with my team and get back to you tomorrow.

Regards,

Harrison Overturf

• Hi Ian,

As you pointed out this design example uses 1.5A which is both the maximum output current for the application as well as for the chip itself. Because of that, Io, Iout, and Ioutmax are used interchangeably within the design example. By using the maximum output current of the chip, the equations calculate the worst case values for the given set of operating conditions.

To better approximate the parameters for your application, try inserting your expected maximum output current into these equations.

There is also a calculator tool available on the product folder that can help you quickly calculate component values for your given application requirements.

Regards,

Harrison Overturf