UC3770A

High Performance Stepper Motor Drive Circuit UC3770A UC3770B FEATURES Full-Step, Half-Step and Micro-Step Capability. Bipolar Output Current up to 2A. Wide Range of Motor Supply Voltage: 10–50V Low Saturation Voltage Wide Range of Current Control: 5mA–2A. Current Levels Selected in Steps or Varied Continuously. Thermal Protection and Soft Intervention. DESCRIPTION The UC3770A and UC3770B are high-performance full bridge drivers that offer higher current and lower saturation voltage than the UC3717 and the UC3770. Included in these devices are LS-TTL compatible logic inputs, current sense, monostable, thermal shutdown, and a power H-bridge output stage. Two UC3770As or UC3770Bs and a few external components form a complete microprocessor-controllable stepper motor power system. Unlike the UC3717, the UC3770A and the UC3770B require external high-side clamp diodes. The UC3770A and UC3770B are identical in all regards except for the current sense thresholds. Thresholds for the UC3770A are identical to those of the older UC3717 permitting drop-in replacement in applications where high-side diodes are not required. Thresholds for the UC3770B are tailored for half stepping applications where 50%, 71%, and 100% current levels are desirable. The UC3770A and UC3770B are specified for operation from 0°C to 70°C ambient. BLOCK DIAGRAM SLUS403A - FEBRUARY 2000 UDG-92039-1 ABSOLUTE MAXIMUM RATINGS Logic Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . ....