General Description
   The AP1021 is a complete microstepping motor driver that can drive two stepper motors, to operate up to 28V motor supply voltage. N-channel LDMOS FETs are built in both high and low side for output driver to achieve small package. It also includes under voltage detection and thermal shut down circuits. It is suitable for driving various types of stepper motors.

FEATUREs
• Built-in PWM Current Control Stepper Motor Driver
• SPI Interface
• Full Programmable Excitation Mode up to 1/64 step
• Control Supply Voltage (VC) 3.0V to 5.5V
• Motor Drive Operating Voltage(VM) 2.0V to 28V
• H-Bridge On Resistance 1.0
• Adjustable PWM Motor Current by VIS pins.
• Built-in UVLO(Under Voltage Lock Out circuit)
• Built-in TSD(Thermal Shut Down circuit)
• Built-in Charge Pump Circuit
• Operating Temperature Range -40°C to +85°C
• Small 32-pin QFN (5mm×5mm) Package