UC3770A UC3770B High Performance Stepper Motor Drive Circuit FEATURES DESCRIPTION • 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 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. • Wide Range of Current Control: 5mA–2A. • Current Levels Selected in Steps or Varied Continuously. • Thermal Protection and Soft Intervention. 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 UDG-92039-1 SLUS403A - FEBRUARY 2000 UC3770A UC3770B ABSOLUTE MAXIMUM RATINGS Logic Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V Output Supply Voltage, VMM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50V Logic Input Voltage (Pins 7, 8, 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V Analog Input Voltage (Pin 10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VCC Reference Input Voltage (Pin 11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15V Logic Input Current (Pins 7, 8, 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –10mA Analog Input Current (Pins 10, 11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –10mA Output Current (Pins 1, 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 2A Junction Temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +150°C Note 1: All voltages are with respect to Gnd (DIL Pins 4, 5, 12, 13); all currents are positive into, negative out of the specified terminal. Note 2: Consult Unitrode Integrated Circuits databook for thermal limitations and considerations of packages. CONNECTION DIAGRAMS DIL-16 (Top View) J Or N Package PACKAGE PIN FUNCTION PLCC-28 (Top View) Q Package FUNCTION PIN Gnd VM N/C AOUT N/C Emitters Gnd BOUT Timing VM Gnd VCC I1 Phase I0 N/C Current VR N/C Gnd 1-3 4 5 6 7 8 9 10 11 12 13-17 18 19 20 21 22 23 24 25-27 28 ELECTRICAL CHARACTERISTICS: (All tests apply with VM = 36V, VCC = 5V, VR = 5V, No Load, and 0°C<TA<70°C, unless otherwise stated, TA = TJ.) UC3770A PARAMETER TEST CONDITIONS Supply Voltage VM (Pins 3, 14) TYP 10 Logic Supply Voltage VCC (Pin 6) Logic Supply Current ICC (Pin 6) MIN 4.75 UC3770B MAX MIN 45 10 4.75 TYP MAX UNITS 45 V 5 5.3 5 5.3 V IO = I1 = H, IM = 0 15 25 15 25 mA IO = I1 = L, IM = 0 18 28 18 28 mA IO = I1 = H, IM = 1.3A 33 40 33 40 mA Thermal Shutdown Temperature +170 Logic Threshold (Pins 7, 8, 9) 0.8 °C +170 2.0 0.8 2.0 V Input Current Low (Pin 8) VI = 0.4V -100 -100 µA Input Current Low (Pins 7, 9) VI = 0.4V -400 -400 µA Input Current High (Pins 7, 8, 9) VI = 2.4V 10 µA Comparator Threshold (Pin 10) VR = 5V, I0 = L, I1 = L 400 415 430 400 415 430 mV VR = 5V, I0 = H, I1 = L 240 255 265 290 300 315 mV VR = 5V, I0 = L, I1 = H 70 80 90 195 210 225 mV ±20 µA 35 ms 10 ±20 Comparator Input Current (Pin 10) Off Time RT = 56k, CT = 820pF 25 2 30 35 25 30 UC3770A UC3770B ELECTRICAL CHARACTERISTICS (cont.): (All tests apply with VM = 36V, VCC = 5V, VR = 5V, No Load, and 0°C<TA<70°C, unless otherwise stated, TA = TJ.) UC3770A PARAMETER TEST CONDITIONS MIN TYP UC3770B MAX Turn Off Delay Sink Driver Saturation Voltage Source Driver Saturation Voltage Output Leakage Current MIN 2 2 ms 0.8 0.8 V IM = 1.3A 1.3 1.3 V IM = 1.0A 1.3 1.3 V IM = 1.3A 1.6 1.6 V VM = 45V 100 100 µA TA = +25°C 1.8 5.0 1.6 4.5 ICC – mA VCE SAT HIGH – V MAX UNITS IM = 1.0A TA = +25°C 1.4 1.2 4.0 3.5 1.0 3.0 0.8 2.5 0.6 0.2 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 OUTPUT CURRENT – A OUTPUT CURRENT – A Figure 1. Typical source saturation voltages vs. load current Figure 3. Typical supply current vs. load current. POWER DISSIPATION (W) TA = +25°C VCE SAT LOW – V TYP 1.4 1.2 1.0 0.8 0.6 0.4 0.2 5 4 3 2 1 0 0 0.5 1 1.5 OUTPUT CURRENT (A) 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 OUTPUT CURRENT – A Figure 2. Typical sink saturation voltages vs. load current Figure 4. Typical power dissipation vs. output current. 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