To get the maximum torque, you will need a high power driver like a Geckodrive. However, if you do not need the maximum possible, use an inexpensive chopper driver like the DRV8825 from Pololu and set the winding current to about 1.5 amperes.
abhi11207:
I am building a CNC machine based on NEMA 23 stepper motor with following specifications:
........
Is there any alternative to these IC's? I don't wanna purchase a ready made driver because the cost will increase too much.
The TB6560 is available already built, cheap from China on eBay. However, be prepared to fix them. I forget the details, but many of them seem to share the same flaws, but once fixed, reviews are good.
That said - note that both of these chips are considered "obsolete" - in this case, however - as long as it isn't for a portable or otherwise battery-operated device (and a CNC machine should be plugged in) - it should be perfectly capable, provided that the upper limit on voltage of the L298 isn't lower than that of the motor's limit (otherwise you can't obtain max speed). If you can round up the L297 chips needed, and incorporate them into your design (and you don't need any real advanced drive capabilities which newer systems might have) - then you might want to try them out.
Or - spend the money and get something more recent.
Regarding the need for a chopper driver, the L297 is the complementary controller IC for the L298:
I guess you missed the OP's first post wherein he states his phase current is 2.8A, and other posters have advised the L298/293 devices are not only obsolete but not up to the task at those currents.
It has 2 MOSFET H-bridges using discrete MOSFETs and chopper-control circuitry.
No single-chip solution for 3A is really viable as lots of power would be dissipated in the
chip, almost as much as in the motor, integrated DMOS MOSFETs are 0.2 ohms or
more, discrete MOSFETs (vertical current flow) can be 0.01 ohms or less...