NJM3775 DUAL STEPPER MOTOR DRIVER n GENERAL DESCRIPTION n PACKAGE OUTLINE The NJM3775 is a switch-mode (chopper), constant- current driver with two channels: one for each winding of a two-phase stepper motor. NJM3775 is equipped with a Disable input to simplify half-stepping operation. The NJM3775 contains a clock oscillator, which is common for both driver channels, a set of comparators and flip-flops implementing the switching control, and NJM3775E3 NJM3775D2 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. NJM3775FM2 n FEATURES Dual chopper driver 750 mA continuous output current per channel Digital filter on chip eliminates external filtering components Packages DIP22 / PLCC28 / SOP24 JEDEC 300mil (Batwing) n BLOCK DIAGRAM E Phase Dis V C 1 1 1 R1 1 NJM3775 V V CC CC R Q + S M A1 Logic M B1 V MM1 + V MM2 M B2 Logic M A2 RC S Q + R Dis E Phase V C GND 2 2 2 R2 2 Figure 1. Block diagramNJM3775 n PIN CONFIGURATIONS M 1 22 M B1 B2 NC 1 24 NC E E 2 21 1 2 2 23 MB MB 2 1 M 3 20 M E E A1 A2 3 22 2 1 M 5 25 Phase A2 2 21 MA 4 MA 2 1 V 4 19 V MM1 MM2 E 6 24 Dis 2 2 20 VMM 5 VMM 1 2 M 7 23 V B2 CC NJM GND 5 18 GND GND GND 6 19 M 8 22 RC B1 NJM3775FM2 3775E3 NJM GND 6 17 GND GND 9 21 GND 7 18 Dis GND 1 3775D2 E 10 20 Phase 1 1 8 17 VR VR 1 2 V 7 16 V R1 R2 M 11 19 C A1 1 16 C2 9 C 1 C 8 15 C 1 2 15 Phase 10 Phase 2 1 Phase Phase 9 14 Dis 11 14 Dis 1 2 2 1 RC 12 13 V cc Dis 10 13 Dis 1 2 12 RC 11 V CC Figure 2. Pin configurations n PIN DESCRIPTION SOP DIP PLCC Symbol Description 2 1 8 M Motor output B, channel 1. Motor current flows from M to M when Phase is HIGH. B1 A1 B1 1 32 10 E Common emitter, channel 1. This pin connects to a sensing resistor R to ground. 1 S 43 11 M Motor output A, channel 1. Motor current flows from M to M when Phase is HIGH. A1 A1 B1 1 54 12 V Motor supply voltage, channel 1, +10 to +40 V. V and V should be connected together. MM1 MM1 MM2 6,7 5, 6, 1-3, 9, GND Ground and negative supply. Note: these pins are used thermally for heat-sinking. 18,19 17, 18 13-17, Make sure that all ground pins are soldered onto a suitably large copper ground plane 28 for efficient heat sinking. 87 18 V Reference voltage, channel 1. Controls the comparator threshold voltage and hence the output R1 current. 98 19 C Comparator input channel 1. This input senses the instantaneous voltage across the sensing 1 resistor, filtered by the internal digital filter or an optional external RC network. 10 9 20 Phase Controls the direction of motor current at outputs M and M . Motor current flows from M to 1 A1 B1 A1 M when Phase is HIGH. B1 1 11 10 21 Dis Disable input for channel 1. When HIGH, all four output transistors are turned off, which results 1 in a rapidly decreasing output current to zero. 12 11 22 RC Clock oscillator RC pin. Connect a 12 kohm resistor to V and a 4 700 pF capacitor to ground CC to obtain the nominal switching frequency of 23.0 kHz and a digital filter blanking time of 1.0m s. 13 12 23 V Logic voltage supply, nominally +5 V. CC 14 13 24 Dis Disable input for channel 2. When HIGH, all four output transistors are turned off, which results 2 in a rapidly decreasing output current to zero. 15 14 25 Phase Controls the direction of motor current at outputs M and M . Motor current flows from M to 2 A2 B2 A2 M when Phase is HIGH. B2 2 16 15 26 C Comparator input channel 2. This input senses the instantaneous voltage across the sensing 2 resistor, filtered by the internal digital filter or an optional external RC network. 17 16 27 V Reference voltage, channel 2. Controls the comparator threshold voltage and hence the output R2 current. 20 19 4 V Motor supply voltage, channel 2, +10 to +40 V. V and V should be connected together. MM2 MM1 MM2 21 20 5 M Motor output A, channel 2. Motor current flows from M to M when Phase is HIGH. A2 A2 B2 2 22 21 6 E Common emitter, channel 2. This pin connects to a sensing resistor R to ground. 2 S 23 22 7 M Motor output B, channel 2. Motor current flows from M to M when Phase is HIGH. B2 A2 B2 2 V 12 4 V MM1 MM2 GND 13 3 GND GND 14 2 GND GND 15 1 GND GND 16 28 GND GND 17 27 V R2 V 18 26 C R1 2