REGULATING PULSE WIDTH MODULATOR

SG1526B/SG2526B/SG3526B REGULATING PULSE WIDTH MODULATOR DESCRIPTION The SG1526B is a high-performance pulse width modulator for switching power supplies which offers improved functional and electrical characteristics over the industry-standard SG1526. A direct pin-for-pin replacement for the earlier device with all its features, it incorporates the following enhancements: a bandgap reference circuit for improved regulation and drift characteristics, improved undervoltage lockout, lower temperature coefficients on oscillator frequency and current-sense threshold, tighter tolerance on softstart time, much faster SHUTDOWN response, improved double-pulse supperession logic for higher speed operation, and an improved output driver design with low shoot-through current, and faster rise and fall times. This versatile device can be used to implement single-ended or push-pull switching regulators of either polarity, both transformer-less and transformer-coupled. The SG1526B is specified for operation over the full military ambient temperature range of -55°C to 150°C. The SG2526B is characterized for the industrial range of -25°C to 150°C, and the SG3526B is designed for the commercial range of 0°C to 125°C. FEATURES • • • • • • • • • • • • • • • • • 8 to 35 volt operation 5V low drift 1% bandgap reference 1Hz to 500KHz oscillator range Dual 100mA source/sink Digital current limiting Double pulse suppression Programmable deadtime Improved undervoltage lockout Single pulse metering Programmable soft-start Wide current limit common mode range TTL/CMOS compatible logic ports Symmetry correction capability Guaranteed 6 unit synchronization Shoot thru currents less than 100mA Improved shutdown delay Improved rise and fall time HIGH RELIABILITY FEATURES - SG1526B ♦ Available to MIL-STD-883 ♦ MIL-M38510/12603BVA - JAN1526BJ ♦ Radiation data available ♦ LMI level "S" processing available BLOCK DIAGRAM VREF +VIN GROUND RD RT CT Reference Regulator Undervoltage Lockout +VC To Internal Circuitry Oscillator SYNC OUTPUT A RESET CSOFTSTART COMPENSATION + ERROR Soft Start +VIN S Amp D Q METERING F/F Q S T R Q Q Q TOGGLE F/F OUTPUT B MEMORY F/F — ERROR + C.S. — C.S. SHUTDOWN 4/90 Rev 1.1 2/94 Copyright © 1994 1 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc. SG1526B/SG2526B/SG3526B ABSOLUTE MAXIMUM RATINGS (Note 1) (Note 1) Input Voltage (VIN ) ............................................................... 40V Collector Supply Voltage (VC) ............................................. 40V Logic Inputs ......................................................... -0.3V to 5.5V Analog Inputs .......................................................... -0.3V to V IN Source/Sink Load Current (each output) ....................... 200mA Reference Load Current .................................................. 50mA Note 1. Exceeding these ratings could cause damage to the device. Logic Sink Current ........................................................... 15mA Operating Junction Temperature Hermetic (J, L Packages) ............................................. 150°C Plastic (N, DW Packages) ............................................ 150°C Storage Temperature Range ............................ -65°C to 150°C Lead Temperature (Soldering, 10 Seconds) ................... 300°C THERMAL DATA J Package: Thermal Resistance-Junction to Case, θ JC .................. 25°C/W Thermal Resistance-Junction to Ambient, θ JA .............. 70°C/W N Package: Thermal Resistance-Junction to Case, θ JC .................. 30°C/W Thermal Resistance-Junction to Ambient, θ JA ............. 60°C/W DW Package: Thermal Resistance-Junction to Case, θ JC .................. 35°C/W Thermal Resistance-Junction to Ambient, θ JA ............. 90°C/W L Package: Thermal Resistance-Junction to Case, θ JC ................... 35°C/W Thermal Resistance-Junction to Ambient, θ JA ........... 120°C/W Note A. Junction Temperature Calculation: TJ = TA + (PD x θJA). Note B. The above numbers for θ JC are maximums for the limiting thermal resistance of the package in a standard mounting configuration. The θ JA numbers are meant to be guidelines for the thermal performance of the device/pcboard system. All of the above assume no ambient airflow. RECOMMENDED OPERATING CONDITIONS (Note 2) Input Voltage ............................................................. 8V to 35V Collector Supply Voltage ........................................ 4.5V to 35V Sink/Source Load Current (each output) ................ 0 to 100mA Reference Load Current ........................................... 0 to 20mA Oscillator Frequency Range .............................. 1Hz to 500KHz Oscillator Timing Resistor .................................. 2KΩ to 150KΩ Note 2. Range over which the device is functional. Oscillator Timing Capacitor ............................... 470pF to 20µF Available Deadtime Range at 40KHz ...................... 5% to 50% Operating Junction Temperature Range: SG1526B ....................................................... -55°C to 125°C SG2526B ......................................................... -25°C to 85°C SG3526B ............................................................ 0°C to 70°C ELECTRICAL CHARACTERISTICS (Unless otherwise specified, these specifications apply over the operating ambient temperatures for SG1526B with -55°C ≤ T A ≤ 125°C, SG2526B with -25°C ≤ TA ≤ 85°C, SG3526B with 0°C ≤ TA ≤ 70°C, and VIN = 15V. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.) Parameter Reference Section (Note 3) Output Voltage Line Regulation Load Regulation Temperature Stability (Note 9) Total Output Voltage Range (Note 9) Short Circuit Current Undervoltage Lockout Section RESET Output Voltage RESET Output Voltage Test Conditions TJ = 25°C VIN = 8 to 35V IL = 0 to 20mA Over Operating TJ VREF = 0V VREF = 3.8V VREF = 4.8V SG1526B/2526B SG3526B Units Min. Typ. Max. Min. Typ. Max. 4.95 5.00 5.05 4.90 5.00 5.10 20 10 10 7 10 20 10 25 50 15 50 15 4.90 5.00 5.10 4.85 5.00 5.15 25 50 125 25 50 125 0.2 4.8 0.4 2.4 0.2 4.8 0.4 V mV mV mV V mA V V 2.4 4/90 Rev 1.1 2/94 Copyright © 1994 2 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc. SG1526B/SG2526B/SG3526B ELECTRICAL CHARACTERISTICS (continued) Parameter Oscillator Section (Note 4) Initial Accuracy Voltage Stability Temperature Stability (Note 9) Minimum Frequency (Note 9) Maximum Frequency Sawtooth Peak Voltage Sawtooth Valley Voltage SYNC Pulse Width Error Amplifier Section (Note 5) Input Offset Voltage Input Bias Current Input Offset Current DC Open Loop Gain High Output Voltage Low Output Voltage Common Mode Rejection Supply Voltage Rejection PWM Comparator Section (Note 4) Minimum Duty Cycle Maximum Duty Cycle Test Conditions TJ = 25°C VIN = 8 to 35V Over Operating TJ RT = 150KΩ, CT = 20µF RT = 2KΩ, CT = 470pF VIN = 35V VIN = 8V RL = 2.0KΩ to VREF RS ≤ 2KΩ RL ≥ 10MΩ VPIN1 - VPIN2 ≥ 150mV, ISOURCE = 100µA VPIN2 - VPIN1 ≥ 150mV, ISINK = 100µA RS ≤ 2KΩ VIN = 8V to 35V VCOMPENSATION = 0.4V VCOMPENSATION = 3.6V 64 3.6 70 66 SG3526B SG1526B/2526B Units Min. Typ. Max. Min. Typ. Max. ±3 0.5 7 500 2.5 0.5 ±8 1.0 10 1.0 3.5 1.1 2 500 2.5 0.5 ±3 0.5 3 ±8 1.0 5 1.0 3.5 1.1 2 % % % Hz KHz V V µs mV nA nA dB V V dB dB % % V V µA µA ns mV µA ns V µA V V V V µA µs µs mA 3.0 1.0 1.0 3.0 1.0 1.0 5 2 -350 -1000 35 100 72 60 4.2 3.6 0.2 0.4 94 70 80 66 0 2 10 -350 -2000 35 200 72 4.2 0.2 0.4 94 80 0 45 2.4 49 4 0.2 0.4 -125 -200 -225 -360 200 100 -3 110 -10 400 0.4. 150 45 2.4 49 4 0.2 0.4 -125 -200 -225 -360 200 100 -3 120 -10 400 0.4. 150 Digital Ports (SYNC, SHUTDOWN, and RESET) HIGH Output Voltage ISOURCE = 40µA LOW Output Voltage ISINK = 3.6mA VIH = 2.4V HIGH Input Current VIL = 0.4V LOW Input Current (Note9) SHUTDOWN Delay to Output Current Limit Comparator Section (Note 6) Sense Voltage RS ≤ 50Ω Input Bias Current Delay to Output (Note 9) Soft-Start Section Error Clamp Voltage RESET = 0.4V CS Charging Current RESET = 2.4V Output Drivers (each output) (Note 7) HIGH Output Voltage ISOURCE = 20mA ISOURCE = 100mA LOW Output Voltage ISINK = 20mA ISINK = 100mA Collector Leakage VC = 40V Rise Time CL = 1000pF Fall Time CL = 1000pF Power Consumption Section (Note 8) Standby Current SHUTDOWN = 0.4V Note 3. Note 4. Note 5. Note 6. IL = 0mA FOSC = 40KHz (RT = 4.12KΩ ±1%, CT = .01µF ±1%, RD = 0Ω) VCM = 0 to 5.2V VCM = 0 to 12V 90 80 50 0.1 100 50 0.1 100 12.5 13.5 12.5 13.5 12 13 12 13 0.2 0.3 0.2 0.3 2 1.2 1.2 2 50 150 50 150 0.3 0.4 0.3 0.4 0.1 0.15 0.1 0.15 18 30 18 30 Note 7. VC = 15V Note 8. VIN = 35V Note 9. These parameters, although guaranteed over the recommended operating conditions, are not tested in production. 4/90 Rev 1.1 2/94 Copyright © 1994 3 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc. SG1526B/SG2526B/SG3526B CHARACTERISTIC CURVES FIGURE 1. REFERENCE VOLTAGE VS. SUPPLY VOLTAGE FIGURE 2. REFERENCE TEMPERATURE STABILITY FIGURE 3. REFERENCE SHORT CIRCUIT FIGURE 4. REFERENCE RIPPLE REJECTION FIGURE 5. UNDER VOLTAGE LOCKOUT FIGURE 6. ERROR AMPLIFIER OPEN LOOP GAIN VS. FREQUENCY FIGURE 7. SOFTSTART TIME CONSTANT VS. CS FIGURE 8. CURRENT LIMIT TRANSFER FUNCTION FIGURE 9. COMPARATOR INPUT TO DRIVER OUTPUT DELAY 4/90 Rev 1.1 2/94 Copyright © 1994 4 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc. SG1526B/SG2526B/SG3526B CHARACTERISTIC CURVES (continued) FIGURE 10. STANDBY CURRENT VS. SUPPLY VOLTAGE FIGURE 11. OUTPUT DRIVER DEADTIME VS. CT VALUE FIGURE 12. OUTPUT