SG1846

SG1846/SG2846/SG3846 CURRENT MODE PWM CONTROLLER DESCRIPTION The SG1846 family of control ICs provides all of the necessary features to implement fixed frequency, current mode control schemes while maintaining a minimum external parts count. The superior performance of this technique can be measured in improved line regulation, enhanced load response characteristics, and a simpler, easier-to-design control loop. Topological advantages include inherent pulse-by-pulse current limiting capability, automatic symmetry correction for push-pull converters, and the ability to parallel “power modules” while maintaining equal current sharing. Protection circuitry includes built-in under-voltage lockout and programmable current limit in addition to soft start capability. A shutdown function is also available which can initiate either a complete shutdown with automatic restart or latch the supply off. Other features include fully latched operation, double pulse suppression, deadtime adjust capability, and a ±1% trimmed bandgap reference. FEATURES • Automatic feed forward compensation • Programmable pulse by pulse current limiting • Automatic symmetry correction in push-pull configuration • Enhanced load response characteristics • Parallel operation capability for modular power systems • Differential current sense amplifier with wide common mode range • Double pulse suppression • 200mA totem-pole outputs • ± 1% bandgap reference • Under-voltage lockout • Soft-start capability • Shutdown capability • 500KHz operation HIGH RELIABILITY FEATURES - SG1846 ♦ Available to MIL-STD - 883 ♦ Radiation data available ♦ LMI level "S" processing available BLOCK DIAGRAM 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. SG1846 ABSOLUTE MAXIMUM RATINGS (Note 1 and 2) Supply Voltage (+VIN ) .......................................................... 40V Collector Supply Voltage(VC) .............................................. 40V Analog Inputs (Pins 3, 4, 5, 6, & 16) ...................... -0.3V to +VIN Logic Input ........................................................... -0.3V to 5.5V Soure/Sink Load current (continuous) .......................... 200mA Source/Sink Load Current (peak, 200ns) ...................... 500mA Reference Load Current .................................................. 30mA Soft Start Sink Current ..................................................... 50mA Note 1. Values beyond which damage may occur. Note 2. Pin numbers refer to ceramic J package. Sync Output Current ........................................................... 5mA Error Amplifier Output Current ............................................ 5mA Oscillator Charging current (Pin 9) ..................................... 5mA Operating Junction Temperature Hermetic (J, L, F Packages) ........................................ 150°C Plastic (N, DW Package) ............................................. 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 .................. 30°C/W Thermal Resistance-Junction to Ambient, θ JA .............. 80°C/W N Package: Thermal Resistance-Junction to Case , θ JC .................. 40°C/W Thermal Resistance-Junction to Ambient, θ JA ............. 65°C/W DW Package: Thermal Resistance-Junction to Case , θ JC ................... 40°C/W Thermal Resistance-Junction to Ambient, θ JA ............. 95°C/W F Package: Thermal Resistance-Junction to Case , θ JC .................. 70°C/W Thermal Resistance-Junction to Ambient, θ JA ........... 115°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 3) Supply Voltage Range ............................................... 8V to 40V Collector Supply Voltage Range ............................. 4.5V to 40V Source/Sink Output Current (continuous) ...................... 100mA Source/Sink Output Current (peak 200ns) .................... 200mA Reference Load Current ........................................... 0 to 10mA Oscillator Frequency Range ........................... 1KHz to 500KHz Note 3. Range over which the device is functional. Oscillator Timing Resistor (RT) ........................... 2KΩ to 100KΩ Oscillator Timing Capacitor (CT) .................... 1000 pF to 0.1µF Operating Ambient Temperature Range SG1846 ........................................................... -55°C to 125°C SG2846 ............................................................. -25°C to 85°C SG3846 ................................................................ 0°C to 70°C ELECTRICAL CHARACTERISTICS (Unless otherwise specified, these specifications apply over the operating ambient temperatures for SG1846/SG1847 with -55 ° C ≤ TA ≤ 125°C, SG2846 with -25° C ≤ TA ≤ 85°C, SG3846 with 0° C ≤ TA ≤ 70°C, +VIN = 15V. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.) Parameter Reference Section Output Voltage Line Regulation Load Regulation Temperature Stability (Note 4) Total Output Variation (Note 4) Output Noise Voltage (Note 4) Long Term Stability (Note 4) Short Circuit Output Current Test Conditions SG1846 SG3846 Units SG2846 Min. Typ. Max. Min. Typ. Max. 5.05 5.10 5.15 5.00 5.10 5.20 V 20 5 5 20 mV 15 3 3 15 mV 0.4 0.4 mV/°C 5.20 4.95 5.25 V 5.00 100 100 µV mV 5 5 -10 -45 -10 -45 mA TJ = 25°C, IO = 1mA VIN = 8V to 40V IL = 1mA to 10mA Line, Load and Temperature 10Hz ≤ f ≤ 10KHz. TJ = 25°C TJ = 125°C, 1000Hrs. VREF = 0V 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. SG1846 ELECTRICAL CHARACTERISTICS (continued) Parameter Oscillator Section (Note 9) Initial Accuracy Voltage Stability Temperature Stability (Note 4) Sync Output High Level Sync Output Low Level Sync Input High Level Sync Input Low Level Sync Input Current Error Amp Section Input Offset Voltage Input Bias Current Input Offset Current Common Mode Range Open Loop Voltage Gain Unity Gain Bandwidth (Note 4) CMRR PSRR Output Sink Current Output Source Current High Level Output Voltage Low Level Output Voltage Current Sense Amplifier Section Amplifier Gain (Notes 5 & 6) Maximum Differential (Note 6) Input Signal (VPIN 4 - VPIN 3)(Note 5) Input Offset Voltage (Note 5) CMRR PSRR Input Bias Current (Note 5) Input Offset Current (Note 5) Input Common Mode Range Delay to Outputs (Note 4) Current Limit Adjust Section Current Limit Offset Voltage(Note 5) Input Bias Current Shutdown Terminal Section Threshold Voltage Input Voltage Range Minimum Latching Current (IPIN 1) (Note 7) Maximum Non-Latching Current (IPIN 1) (Note 8) Delay to Outputs (Note 4) Output Section Collector Emitter Voltage Collector Leakage Current Output Low Level Output High Level Rise Time (Note 4) Fall Time (Note 4) Test Conditions SG1846 SG3846 Units SG2846 Min. Typ. Max. Min. Typ. Max. 39 43 1 1 4.35 2.3 47 2 39 43 1 1 4.35 2.3 47 2 KHz % % V V V V mA TJ = 25° C VIN = 8V to 40V Over Operating Range 3.9 Pin 8 = 0V Pin 8 = 0V Sync Voltage = 5.25V, Pin 8 = 0V 3.9 3.9 2.5 3.9 2.5 1.5 5 -1 250 0 80 0.7 75 80 2 -0.4 4.3 2.5 2.5 1.5 10 -2 250 1.2 0.5 -0.6 40 1.2 0.5 -0.6 40 105 1.0 100 105 6 -0.5 4.6 0.7 2.75 1.2 5 83 84 -2.5 0.08 200 VIN = 8V to 40V VO = 1.2V to 3V, VCM = 2V TJ = 25°C VCM = 0V to 38V, VIN = 40V VIN = 8V to 40V VID = - 15mV to -5V, VPIN 7 = 1.2V VID = 15mV to 5V, VPIN 7 = 2.5V RL = 15KΩ (Pin 7) RL = 15KΩ (Pin 7) VPIN 3 = 0V, Pin 1 Open Pin 1 Open RL = 15KΩ (Pin 7) VPIN 1 = 0.5V, Pin 7 Open VCM = 1V to 12V VIN = 8V to 40V VPIN 1 = 0.5V, Pin 7 Open VPIN 1 = 0.5V, Pin 7 Open TJ = 25°C VPIN 3 = 0, VPIN 4 = 0V, Pin 7 Open VPIN 5 = VREF, VPIN 6 = 0V 0 VIN-2V 80 105 0.7 1.0 75 100 80 105 2 6 -0.4 -0.5 4.3 4.6 0.7 1 2.5 1.1 60 60 2.75 1.2 5 83 84 -2.5 0.08 200 0.45 0.5 -10 350 3.0 mV µA nA V VIN -2V dB MHz dB dB mA mA V V 1 3.0 V V mV dB dB µA µA V ns V µA mV V mA 0.8 600 mA ns V µA V V V V ns ns 2.5 1.1 25 60 60 -10 1 VIN -3 25 -10 1 VIN -3 0 0 500 0.55 0.45 -30 400 VIN 250 0 3.0 0.8 600 40 500 0.5 0.55 -10 -30 350 400 VIN 250 0 3.0 1.5 1.5 300 1.5 1.5 300 TJ = 25°C 40 VC = 40V ISINK = 20mA ISINK = 100mA ISOURCE = 20mA ISOURCE = 100mA CL = 1nF, TJ = 25°C CL = 1nF, TJ = 25°C 13 12 0.1 0.4 13.5 13.5 50 300 50 300 200 0.4 2.1 13 12 0.1 0.4 13.5 13.5 50 300 50 300 200 0.4 2.1 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. SG1846 ELECTRICAL CHARACTERISTICS (continued) Parameter Under-Voltage Lockout Section Start-Up Threshold Threshold Hysteresis Total Standby Current Supply Current Note 4. These parameters although guaranteed over the recommended operating conditions, are not tested in production. Note 5. Parameter measured at trip point of latch with VPIN 5 = VREF , VPIN 6 = 0V. ∆ VPIN 7 Note 6. Amplifier gain defined as : G = ; VPIN 4 = 0V to 1.0V ∆ VPIN 4 Test Conditions SG1846 SG3846 SG2846 Units Min. Typ. Max. Min. Typ. Max. 7.7 0.75 17 8.0 7.7 0.75 17 8.0 V V mA 21 21 Note 7. Current into Pin 1 guaranteed to latch circuit in shutdown state. Note 8. Current into Pin 1 guaranteed not to latch circuit in shutdown state. Note 9. RT = 10K Ω, CT = 4.7nF CHARACTERISTIC CURVES FIGURE 1. REFERENCE VOLTAGE VS. TEMPERATURE FIGURE 2. VREF SHORT CIRCUIT CURRENT VS. TEMPERATURE FIGURE 3. CURRENT SENSE THRESHOLD VS. ERROR AMPLIFIER OUTPUT FIGURE 4. CURRENT SENSE GAIN VS. TEMPERATURE FIGURE 5. OSCILLATOR VALLEY VOLTAGE VS. TEMPERATURE FIGURE 6. OSCILLATOR PEAK VOLTAGE VS. TEMPERATURE 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. SG1846 CHARACTERISTIC CURVES (continued) FIGURE 7. MINIMUM SCR LATCH CURRENT FIGURE 8. CURRENT SENSE DELAY VS. TEMPERATURE FIGURE 9. SHUTDOWN DELAY TO OUTPUT VS. TEMPERATURE FIGURE 10. ERROR AMPLIFIER INPUT OFFSET VOLTAGE VS. TEMPERATURE FIGURE 11. ERROR AMP SINK CURRENT VS. TEMPERATURE FIGURE 12. OUTPUT TRANSISTOR SATURATION VOLTAGE VS. OUTPUT CURRENT (SINK TRANSISTOR) FIGURE 13. OUTPUT TRANSISTOR SATURATION VOLTAGE VS. OUTPUT CURRENT (SOURCE TRANSISTOR) FIGURE 14. SYNC PULSEWIDTH VS. TEMPERATURE FIGURE 15. SYNC PULSEWIDTH VS. TEMPERATURE 4/90 Rev 1.1 2/94 Copyright © 1994 5 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc. SG1846 CHARACTERISTIC CURVES (continued) FIGURE 16. OSCILLATOR FREQUENCY VS. TEMPERATURE FIGURE 17. OSCILLATOR FREQUENCY VS. TEMPERATURE FIGURE 18. DUTY CYCLE VS. TEMPERATURE APPLICATION INFORMATION FIGURE 19- OSCILLATOR FREQUENCY CURVES Oscillator frequency is approximated by the formula: f T ≈ FIGURE 20 - OSCILLATOR CIRCUIT 2.2 RTCT 4/90 Rev 1.1 2/94 Copyright © 1994 6 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc. SG1846 APPLICATION INFORMATION (continued) FIGURE 21 - ERROR AMP OUTPUT CONFIGURATION (Error amplifier can source up to 0.5mA) FIGURE 22 - CURRENT SENSE AMPCONNECTIONS A small RC filter may be required in some applications to reduce switch transients. Differential input allows remote, noise free switching. FIGURE 23 - SINGLE ENDED BOOST CONFIGURATION 4/90 Rev 1.1 2/94 Copyright © 1994 7 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc. SG1846 APPLICATIONS INFORMATION (continued) FIGURE 24 - BUCK CONVERTER WITH CURRENT SENSE WINDING FIGURE 25 - PUSH/PULL CONVERTER WITH SLOPE COMPENSATION 4/90 Rev 1.1 2/94 Copyright © 1994 8 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc. SG1846 APPLICATIONS INFORMATION (continued) FIGURE 26 - PULSE BY PULSE CURRENT LIMITING FIGURE 27 - SOFT START AND SHUTDOWN/RESTART FUNCTIONS VREF < 0.8mA R1 FIGURE 28 - SHUTDOWN WITH AUTO-RESTART VREF >3mA (LATCHED OFF) R1 FIGURE 29 - SHUTDOWN WITHOUT AUTO-RESTART (LATCHED) If VREF < 0.8mA the shutdown latch will commutate R1 If VREF > 3mA the device will latch off R1 when ISS < 0.8mA and a restart cycle will be initiated. until power is recycled. 4/90 Rev 1.1 2/94 Copyright © 1994 9 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc. SG1846 CONNECTION DIAGRAMS & ORDERING INFORMATION Package 16-PIN CERAMIC DIP J - PACKAGE (See Notes Below) Part No. SG1846J/883B SG1846J/DESC SG1846J SG2846J SG3846J SG2846N SG3846N SG2846DW SG3846DW Ambient Temperature Range -55°C to 125°C -55°C to 125°C -55°C to 125°C -25°C to 85°C 0°C to 70° C -25°C to 85°C 0°C to 70°C -25°C to 85°C 0°C to 70°C Connection Diagram C.L./SOFTSTART VREF (-) C.S. (+) C.S. (+) ERROR AMP (-) ERROR AMP COMPENSATION CT SHUTDOWN +VIN OUTPUT B VC GROUND OUTPUT A SYNC RT 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 16-PIN PLASTIC DIP N - PACKAGE 16-PIN WIDEBODY PLASTIC S.O.I.C DW - PACKAGE C.L./SOFTSTART VREF (-) C.S. (+) C.S. (+) ERROR AMP (-) ERROR AMP COMPENSATION CT 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 SHUTDOWN +VIN OUTPUT B VC GROUND OUTPUT A SYNC RT 16-PIN CERAMIC FLAT PACK F - PACKAGE (Note 3) SG1846F/DESC -55°C to 125°C C.L./SOFTSTART VREF (-) C.S. (+) C.S. (+) ERROR AMP (-) ERROR AMP COMPENSATION CT 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 SHUTDOWN +VIN OUTPUT B VC GROUND OUTPUT A SYNC RT 20-PIN CERAMIC LEADLESS CHIP CARRIER L - PACKAGE (Note 3) SG1846L/883B SG1846L/DESC SG1846L -55°C to 125°C -55°C to 125°C -55°C to 125°C 3 2 1 20 19 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. N.C. C.L./SOFTSTART VREF (-) C.S. (+) C.S. N.C. (+) ERROR AMP (-) ERROR AMP COMPENSATION CT 4 5 6 7 8 18 17 16 15 14 9 10 11 12 13 11.N.C. 12.RT 13.SYNC 14.OUTPUT A 15.GROUND 16.N.C. 17.VC 18.OUTPUT B 19.VIN 20.SHUTDOWN Notes: 1. Contact factory for JAN and DESC part availability. 2. All parts are viewed from the top. 3. Consult factory for product availability. 4/90 Rev 1.1 2/94 Copyright © 1994 10 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 LINFINITY Microelectronics Inc.