Test Procedure for the STK681-332GEVB Evaluation Board Evaluation Board Setup [Supply Voltage] Vcc (10 to 38V: STK681-332-E): Power Supply for stepping motor Vcc (10 to 29V: STK681-352-E): Power Supply for stepping motor Vref (0 to 2.0V): Const. Current Control for Reference Voltage VDD (5V) : Power Supply for internal logic IC [Operation Guide] 1. Motor Connection: Connect the motor to OUT1 and OUT2. 2. Initial Condition Setting: Set to signal condition IN1=H, IN2=H, and ENABLE=L. 3. Power Supply: <STK681-332-E> At first, supply DC voltage to VDD (5.0V), and VREF. Next, supply DC voltage to Vcc. <STK681-352-E> At first, supply DC voltage to VDD (3.3V or 5.0V), and VREF. Next, supply DC voltage to Vcc. 4. Set to Forward or Reverse signal condition with ENABLE=Low. Turn “High” ENABLE signal. Output current flows between OUT1 and OUT2. 5. Motor Operation [Setting the current limit using the Vref pin] Output current peak (Iop) = (Vref÷4.9) ÷Rs “4.9” in the above formula indicates the portion of the Vref voltage that is divided using the circuit inside the control IC. Vref=(R2÷(R1+R2))×5.0V(or 3.3V) Rs is the external current detection resistance value of the HIC, and Vref≦2.0V must be satisfied so that overcurrent detection is not triggered. 12/30/2013 1 www.onsemi.com Allowable power dissipation, PdPK - W Allowable power dissipation (Reference value) Allowable power dissipation, PdPK (no heat sink) - Ambient temperature, Ta 3 2.5 2 1.5 1 0.5 0 0 20 40 60 80 100 120 Ambient temperature, Ta - °C If you need heat sink to STK681-332 and 352, mount heat sink with something such as clips. Waveform example STK681-332 (Current limit 5A setting) IN1 and IN2; 5V/div, Output current; 5A/div IN1 IN2 OUT2 Output current Positive direction is source current. Peak 8.5A 12/30/2013 2 www.onsemi.com FORWARD BRAKING STK681-332 (Current limit 5A setting) IN1 5V/div, OUT2 20V/div, Output current; 5A/div IN1 OUT2 OUT2 Output current Positive direction is source current. Current limit active. Output is chopped. FORWARD Current control is slow decay. STK681-332 and 352 control MOSFET at Low side by constant-current PWM control system. Current control enters Slow decay mode. 12/30/2013 3 www.onsemi.com STK681-332 and 352 have ENABLE terminal built-in, which controls motor rotation. At the point of ENABLE=High, F3 or F4 at Low side turns on. STK681-332, 352(ENABLE: 20kHz) ENABLE ; 5V/div, OUT1 ; 20V/div, Output current; 0.5A/div ENABLE High duty 60% OUT1 Output current 12/30/2013 4 www.onsemi.com