There are differences for maximum allowable current, operating voltage, line up by drive. Please refer to below table.
Ezi-STEP Driver is a bipolar step driver series with a PWM operation method with 32Bit DSP and can be distinguished by three different types : MNB, MPB and HPB.
The differences are listed below. 

*1 Voltge boosting by internal DC-Dc converter

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Differences of drive dimension are as below.

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