5804

Combining low-power CMOS logic with high-current and high-voltage bipolar outputs, the UCN5804B and UCN5804LB BiMOS II translator/ drivers provide complete control and drive for a four-phase unipolar steppermotor with continuous output current ratings to 1.25 A per phase (1.5 A startup) and 35 V.

The CMOS logic UCN5804B provides the sequencing logic, DIRECTION and OUTPUT ENABLE control, and a power-on reset function. Three stepper-motor drive formats, wave-drive (one-phase), two-phase, and halfstep are externally selectable. The inputs are compatible with standard CMOS, PMOS, and NMOS circuits. TTL or LSTTL of UCN5804B may require the use of appropriate pull-up resistors to ensure a proper input-logic high.

The wave-drive format of UCN5804B consists of energizing one motor phase at a time in an A-B-C-D (or D-C-B-A) sequence. This excitation mode consumes the least power and assures positional accuracy regardless of any winding inbalance in the motor. Two-phase of UCN5804B drive energizes two adjacent phases in each detent position (AB-BC-CD-DA). This sequence mode offers an improved torque-speed product, greater detent torque, and is less susceptible to motor resonance. Half-step excitation of UCN5804B alternates between the one-phase and two-phase modes (A-AB-B-BC-C-CD-D-DA), providing an eight-step sequence.

The bipolar outputs of UCN5804B are capable of sinking up to 1.5 A and withstanding 50 V in the off state (sustaining voltages up to 35 V). Ground-clamp and flyback diodes provide protection against inductive transients. Thermal protection circuitry disables the outputs when the chip temperature is excessive.

Both UCN5804B and UCN5804LB are rated for operation over the temperature range of -20°C to +85°C. The UCN5804B is supplied in a 16-pin dual in-line plastic batwing package with a copper lead frame and heat-sinkable tabs for improved power dissipation capabilities; the UCN5804LB is supplied in a 16-lead plastic SOIC batwing package with a copper lead frame and heat-sinkable tabs.