NJM3717 STEPPER MOTOR DRIVER n GENERAL DESCRIPTION n PACKAGE OUTLINE NJM3717 is a stepper motor diver, which consists of a LS-TTL compatible logic input stage, a current sensor, a monostable multivibrator and a high power H-bridge output stage with built-in protection diodes. The output current is up to 1200mA. Two NJM3717 and a small number of external components form a complete control and drive NJM3717D2 NJM3717E2 unit for stepper motor systems. n FEATURES NJM3717FM2 Half-step and full-step modes Switched mode bipolar constant current drive Wide range of current control 5 - 1200 mA Wide voltage range 10 - 50 V Thermal overload protection Packages DIP16 / PLCC28 / EMP20 n BLOCK DIAGRAM V V V CC MM MM Schmitt Time Trigger Delay Phase 1 1 1 M A I 1 M I B 0 V R 1 1 & & & & + Output Stage + Monostable + t = 0.69 R C off T T GND Current Sensor NJM3717 E T Figure 1. Block diagramNJM3717 n PIN CONFIGURATIONS M 1 20 B E M E B 1 16 T 2 19 M A T M 2 15 A V 3 18 V MM MM N/C 5 25 N/C V V MM 3 14 MM GND 4 17 GND M 6 24 V A R GND NJM GND 4 13 16 GND 5 GND N/C 7 23 C NJM 3717D2 E 8 NJM3717FM2 22 N/C 3717E2 GND GND GND 6 15 5 12 GND GND 9 21 I 0 14 7 GND GND V V 6 11 CC R M 10 20 Phase B V 13 CC 8 V R T 11 19 I 1 I C 7 10 1 I 1 9 12 C Phase I 8 9 0 Phase 10 11 I 0 Figure 2. Pin configurations n PIN DESCRIPTION DIP EMP PLCC Symbol Description 11 10 M Motor output B, Motor current flows from M to M when Phase is high. B A B 2 2 11 T Clock oscillator. Timing pin connect a 56 kW resistor and a 820 pF in parallel between T and Ground. 3,14 3,18 12,4 V Motor supply voltage, 10 to 45 V. V pins should be wired together on MM MM 4,5, 4,5,6,7,14 1,2,3,9,13, PCB. 12,13 15,16,17 14,15,16,17 GND Ground and negative supply. Note these pins are used for heatsinking. 28 Make sure that all ground pins are soldered onto a suitable large copper ground plane for efficient heat sinking. 68 18 V Logic voltage supply normally +5 V. CC 79 19 I Logic input, it controls, together with the I input, the current level in the 1 0 output stage. The controllable levels are fixed to 100, 60, 20, 0%. 8 10 20 Phase Controls the direction of the motor current of M and M outputs. Motor A B current flows from M to M when the phase input is high. A B 911 21 I Logic input, it controls, together with the I input, the current level in the 0 1 output stage. The controlable levels are fixed to 100, 60, 20, 0%. 10 12 23 C Comparator input. This input senses the instantaneous voltage across the sensing resistor, filtered through a RC Network. 11 13 24 V Reference voltage. Controls the threshold voltage of the comparator and R hence the output current. Input resistance: typically 6.8kW 20%. 15 19 6 M Motor output A, Motor current flows from M to M when Phase is high. A A B 16 20 8 E Common emitter. Connect the sense resistor between this pin and ground. V 12 4 V MM MM GND 13 3 GND GND 14 2 GND GND 15 1 GND GND 16 28 GND GND 17 27 N/C V 18 26 N/C CC