UC494A/AC UC495A/AC Advanced Regulating Pulse Width Modulators FEATURES DESCRIPTION • Dual Uncommitted 40V, 200mA Output Transistors • 1% Accurate 5V Reference • Dual Error Amplifiers • Wide Range, Variable Deadtime • Single-ended or Push-pull Operation • Under-voltage Lockout With Hysteresis This entire series of PWM modulators each provide a complete pulse width modulation system in a single monolithic integrated circuit. These devices include a 5V reference accurate to ±1%, two independent amplifiers usable for both voltage and current sensing, an externally synchronizable oscillator with its linear ramp generator, and two uncommitted transistor output switches. These two outputs may be operated either in parallel for singleended operation or alternating for push-pull applications with an externally controlled dead-band. These units are internally protected against doublepulsing of a single output or from extraneous output signals when the input supply voltage is below minimum. • Double Pulse Protection • Master or Slave Oscillator Operation • UC495A: Internal 39V Zener Diode • UC495A: Buffered Steering Control BLOCK DIAGRAM 10/93 The UC495A contains an on-chip 39V zener diode for high-voltage applications where VCC would be greater than 40V, and a buffered output steering control that overrides the internal control of the pulse steering flip-flop. The UC494A is packaged in a 16-pin DIP, while the UC495A is packaged in an 18 pin DIP. The UC494A, UC495A are specified for operation over the full military temperature range of -55°C to +125°C, while the UC494AC, UC495AC are designed for industrial applications from 0°C to +70°C. UC494A/AC UC495A/AC ABSOLUTE MAXIMUM RATINGS (Note 1, 2, 3) RECOMMENDED OPERATING CONDITIONS Supply Voltage, VCC (Note 2). . . . . . . . . . . . . . . . . . . . . . . . 45V Amplifier Input Voltages . . . . . . . . . . . . . . . . . . . . . . VCC + 0.3V Collector Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . 41V Collector Output Current. . . . . . . . . . . . . . . . . . . . . . . . . 250mA Continuous Total Dissipation . . . . . . . . . . . . . . . . . . . . 1000mW @ (or below) 25°C free air temperature range (Note 3) Storage Temperature Range . . . . . . . . . . . . . . . -65° to +150°C Lead Temperature 1/16" (1.6mm) from case for 60 seconds, J Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300°C Lead Temperature 1/16" (1.6mm) from case for 10 seconds, N Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C Note 1: Over operating free air temperature range unless otherwise noted. Note 2: All voltage values are with respect to network ground terminal 3. Note 3: Consult Packaging Section of Databook regarding thermal specifications and limitations of packages. Supply Voltage VCC . . . . . . . . . . . . . . . . . . . . . . . . . . 7V to 40V Error Amplifier Input Voltages . . . . . . . . . . . . . -0.3V to VCC-2V Collector Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V Collector Output Current (each transistor) . . . . . . . . . . . 200mA Current into Feedback Terminal. . . . . . . . . . . . . . . . . . . . 0.3mA Timing Capacitor, CT . . . . . . . . . . . . . . . . . 0.47nF to 10,000nF Timing Resistor, RT . . . . . . . . . . . . . . . . . . . . . 1.8kΩ to 500kΩ Oscillator Frequency . . . . . . . . . . . . . . . . . . . . 1kHz to 300kHz Operating Free Air Temperature UC494A, UC495A . . . . . . . . . . . . . . . . . . . . -55°C to +125°C UC494AC, UC495AC . . . . . . . . . . . . . . . . . . . . 0°C to +70°C CONNECTION DIAGRAMS DIL-18 (TOP VIEW) J or N Package UC494A/AC DIL-18 (TOP VIEW) J or N Package UC495A/AC ELECTRICAL CHARACTERISTICS: Unless otherwise stated, over recommended operating free-air temperature range, VCC = 15V, f = 10kHz, TA = TJ. PARAMETER TEST CONDITIONS Reference Section Output Voltage VREF IO = 1mA, TA = 25°C Input Regulation VCC = 7V to 40V Output Regulation IO = 1mA to 10mA Output Voltage Over Temperature ∆TA = Min. to Max. Short Circuit Output Current VREF = 0, TA = 25°C (Note 1) Oscillator Section Frequency (Note 2) CT = 0.01µF, RT = 12kΩ Standard Deviation Of Frequency (Note 3) All Values of VCC, CT, RT, TA Constant Frequency Change With Voltage VCC = 7V to 40V, TA = 25°C Frequency Change With Temperature CT = 0.01µF, RT = 12kΩ, ∆TA = Min. to Max. Deadtime Control Section (Output Control Connected to VREF) Input Bias Current (Pin 4) V(PIN 4) = 0V to 5.25V Maximum Duty-Cycle (Each Output) V(PIN 4) = 0V 2 MIN TYP 4.95 5 2 1 4.90 10 35 MAX UNITS 5.05 25 15 5.10 50 V mV mV V mA 2 kHz % % % 10 10 0.1 -2 45 -10 µA % UC494A/AC UC495A/AC ELECTRICAL CHARACTERISTICS: Unless otherwise stated, over recommended operating free-air temperature range, VCC = 15V, f = 10kHz, TA = TJ. PARAMETER TEST CONDITION Deadtime Control Section (cont.) (Output Control Connected to VREF) Input Threshold Voltage (Pin 4) Zero Duty-Cycle Maximum Duty-Cycle Amplifier Section Input Offset Voltage VO (PIN 3) = 2.5V Input Offset Current VO (PIN 3) =2.5V Input Bias Current VO (PIN 3) = 2.5V Common-Mode Input Voltage Range VCC = 7V to 40V Open Loop Voltage Gain ∆VO = 3V, VO = 0.5V to 3.5 V Unity Gain Bandwidth Common-Mode Rejection Ratio VCC = 40V, TA = 25°C Output Sink Current (Pin 3) VID = -15mV to -5V, V(PIN 3) = 0.7V Output Source Current (Pin 3) VID = 15mV to 5V, V(PIN 3) = 3.5V Output Section Collector Off-State Current VCE = 40V, VCC = 40V Emitter Off-State Current VCC = VC = 40V, VE = 0 Collector - Emitter Common-Emitter VE = 0, IC = 200mA Saturation Voltage Emitter-Follower VC = 15V, IE = -200mA Output Control Input Current VI = VREF PWM Comparator Section Input Threshold Voltage (Pin 3) Zero Duty-Cycle Input Sink Current (Pin 3) V(PIN 3) = 0.7V Steering Control (UC495A, See Function Table) Input Current V(PIN 13) = 0.4V, Q1 ACTIVE V(PIN 13) = 2.4V, Q2 ACTIVE Deadband Zener Diode Circuit (UC495A) Breakdown Voltage VCC = 45V, IZ = 2mA Sink Current V(PIN 15) = 1V Total Device Standby Supply Current Pin 6 at VREF, All other inputs and outputs open Under Voltage Lockout Hysteresis Switching Characteristics (TA = 25°C) Output Voltage Rise Time Output Voltage Fall Time Output Voltage Rise Time Output Voltage Fall Time MIN 3.3 V V 2 25 -0.2 10 250 -1 mV nA µA V 0 .03 to VCC -2 70 65 0.3 -2 95 800 80 0.7 µA µA V V mA 4.5 V mA -200 300 µA µA mV 39 0.3 45 0.6 V mA 6 9 10 15 6.5 mA mA V mV 200 100 200 100 ns ns ns ns 1.1 1.5 0.3 dB kHz dB mA mA 100 -100 1.3 2.5 3.5 2 4 0.7 500 36 0.2 VCC = 15V VCC = 40V 300 Common-Emitter Configuration RL = 68Ω, CL = 15pF Emitter-Follower Configuration RL = 68Ω, CL=15pF RTCT Note 3: Standard deviation is a measure of the statistical distribution about the mean as derived from the formula: √ MAX UNITS 3 3.5 Note 1: Duration of the short circuit should not exceed one second. 1.1 Note 2: Frequency for other values of CT and RT is approximately f = σ= TYP n 2 Σ (Xn − X) n=1 . n−1 3 100 25 100 40 UC494A/AC UC495A/AC Figure 1. Slaving Two or More Control Circuits Figure 2. Output Circuit of Error Amplifiers Figure 3. Output Connections for Single-Ended and Push-Pull Configurations Figure 4. Internal Buffer with Deadband for Steering Control on UC495A Figure 5. Operation with VIN > 40V Using Internal Zener Figure 6. Error Amplifier Sensing Techniques UNITRODE INTEGRATED CIRCUITS 7 CONTINENTAL BLVD. •MERRIMACK, NH 03054 TEL. (603) 424-2410 • FAX (603) 424-3460 4 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. 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