The NJM3773 is a switch-mode (chopper), constant-current driver with two channels: one for each winding of a two-phase stepper motor. The NJM3773 is also equipped with a Disable input to simplify half-stepping operation. The circuit is well suited for microstepping applications together with an external micro controller. The current control inputs are low current, high impedance inputs, which allows the use of unbuffered DAC or external high resistive resistor divider network. The NJM3773 contains a clock oscillator, which is common for both driver channels, a set of comparators and flip-flops implementing the switching control, and two output H-bridges, including recirculation diodes. Voltage supply requirements are +5 V for logic and +10 to +45 V for the motor. Maximum output current is 750mA per channel.