Power Management AAC242/243 AAC242/243 PRELIMINARY DATA Current Mode PWM Contoller DESCRIPTION The AAC242 and AAC243 are part of AAI’s new family of specialty products for Power Management applications. The AAC242 and AAC243 are high performance integrated circuits designed for Off-line or DC to DC converters using peak current mode control. The AAC24X has a current sense of 250mV in comparison to 1V for AAC14X parts. In offline AC designs the startup is improved by the low start-up current of the family. The integrated soft-start function adds to the easy of using the AAC24X parts in offline applications. The AAC242 and AAC243 are identical except for the Under Voltage Lockout. The AAC242 has UVLOon threshold of 16V and off of 10V making it easy to use in offline supplies where startup requirements for energy storage is necessary. For applications using lower supply voltages the AAC243 has UVLOon of 8.4V and UVLOoff of 7.6V. FEATURES • Low Start-up current • Pulse by pulse current limiting • On board voltage reference • • • • • • • • Under Voltage Lockout with hysteresis The greater than 1A output driver is ideal for driving MOSFETs and low power IGBTs. Rise and fall times are typically less that 30ns with a 1000pF load. The improvements in switching speed can provide improvements in efficiency, higher operating frequency and over current protection. • 100ns leading edge current blanking for reduced filtering • 250mV current sense The AAC24X family has a minimum pulse width of 0.4% allowing operation at very low power without pulse skipping or erratic operation. The narrower pulse width capibilities enhances operation at higher frequencies and voltages. View of the AAC24X shown from the top. The AAC24X family is offered in DIP and SMD packages. The packages are industry standards and are ROHS compliant. Extended temperature is standard with the AAC24X family. © Copyright 2010- ASIC Advantage, Inc. – Simple oscillator circuit Over Voltage protection zener High current output driver Less than 30ns rise and fall times Operation to over 1MHz Peak Current Mode control Integrated Cycles) Soft-Start Function (~330 Clock PIN CONFIGURATION: 8-Lead DIP and SOIC8 AADS00012 / R127B COMP 1 8 VFB AAC242 ISENSE AAC243 5 Rt/Ct 4 - Preliminary - VREF VCC OUT GND October 2010 1/8 Power Management AAC242/243 BLOCK DIAGRAM 8 Vcc UVLO 34V 5.00VREF 5V REF 5 GND REF OK 2.5V OSC 4 Rt/Ct Error Amp OUTPUT 6 11R 2R + S 2 Vf b Vref 7 DVR - R 1V R + Q Current Sense Comparator 1 COMP 3 Isense Open Loop Test Circuit V+ A Rt 4.7K 100K 1 2N3904 2 1K 3 4 4.7K 5K Vref FB Vcc Isense R/C 0.1uF 8 COMP OUT GND 7 1K/1W 6 OUTPUT 5 0.1uF Ct MAXIMUM RATINGS PARAMETER PARAMETERS UNITS CONDITIONS Low impedance source Supply Voltage (Vcc – Ground) MIN. 0 MAX. 30 V Vfb and Isense Amp Inputs -0.3 5.5 V ±1 A 1200 mW DIP 1000 mW SOIC8 150 °C Output Current Power Dissipation Operating Junction Temperature Operating Ambient Temperature -40 105 °C Operating Ambient Temperature -40 125 °C Storage Temperature Range -65 150 °C 300 °C Lead Temperature (10 Second) © Copyright 2010- ASIC Advantage, Inc. – AADS00012 / R127B - Preliminary Extended industrial temp. rated devices Automotive temp. rated devices Soldering - October 2010 2/8 Power Management AAC242/243 ELECTRICAL CHARACTERISTICS Unless otherwise stated, T=25C, Vcc=15V, RT = 10KΩ, CT = 3300pF. PARAMETER PARAMETERS UNITS MIN. TYP. MAX. 4.95 5.00 5.05 V Line Regulation 6 15 mV Load Regulation 3 25 mV CONDITIONS REFERENCE SECTION Output Voltage Temperature Stability Total Output Variation 0.2 4.9 5.1 Long Term Stability Output Short Circuit Current 5 12V<Vcc<25V mV/°C 0C to 130C V Line, Load, and Temperature mV Ta=125°C for 1000 hours -30 -50 -60 mA 47 52 57 KHz Ta=25°C Frequency Change with Voltage 0.2 1 % 12<Vcc<25V Frequency Change with Temp. 1 % Tlow<Ta<Thigh 1.65 Vpp OSCILLATOR SECTION Frequency Initial Accuracy Oscillator Voltage Swing ERROR AMPLIFIER SECTION Voltage Feedback Input 2.45 2.5 Input Bias Current 2.55 V -1 µA Vout=2.5V Open Loop Voltage Gain 90 dB Unity Gain Bandwidth 10 MHz Tj=25°C Power Supply Rejection Ratio 70 dB 12V<Vcc<25V Output Current Sink 12 mA Output Current Source -1 mA Output Voltage Swing High 6 V Output Voltage Swing Low 0.8 V Maximum Duty Cycle 97 % Minimum Duty Cycle 0.4 % PULSE WIDTH MODULATION SECTION Before drop out CURRENT SENSE SECTION Voltage Gain 11.4 12.0 12.6 V Maximum Input Signal 242 250 258 mV Power Supply Rejection Ratio 70 dB Input Bias Current -10 µA Time Delay to Output 300 nS © Copyright 2010- ASIC Advantage, Inc. – AADS00012 / R127B - Preliminary - October 2010 3/8 Power Management AAC242/243 PARAMETER PARAMETERS MIN. TYP. UNITS CONDITIONS MAX. OUTPUT SECTION Voltage Out Low 0.4 V Isink = 20mA Voltage Out Low 2.2 V Isink = 200mA Voltage Out High 13.5 14 V Isink = 20mA Voltage Out High 12.5 13.5 V Isink = 200mA 1.1 V Vcc=6V, Isink = 1mA Voltage Out UVLO Voltage Output Rise Time 30 50 ns CL=1000pF Voltage Output Fall Time 30 50 ns CL=1000pF Current Output Source Peak 1.2 A Current Output Sink Peak 0.7 A UNDER-VOLTAGE LOCKOUT SECTION Voltage Start Threshold (142) 15 16 17 V Voltage Start Threshold (143) 7.8 8.4 9 V Voltage Turnoff Threshold (142) 9 10 11 V Voltage Turnoff Threshold (143) 7 7.6 8.2 V Zener Clamp Voltage 30 34 V Icc≤25mA TOTAL DEVICE SECTION Start-up Supply Current 0.4 Operating Supply Current 0.6 mA 11 mA The improved switching performance increases the high peak current associated with internal and external capacitances and will require careful grounding and PCB trace routing. Bypass and timing capacitors should be of high quality and located carefully with short traces. The reference capacitor must be located very close to the IC with minimum trace lengths. A single point ground should be located at pin 5 ground. The use of a good ground plane is recommended. Under certain conditions of high peak currents it may be advisable to isolate the Vref pin from the bypass capacitor with a resistor to prevent interaction of the high current with the internal oscillator operation. Charge and discharge times are given by the following formulas: TC=0.55RtCt TD=RtCtLn[(0.0063Rt-2.7)/(0.0063Rt-4)] Frequency =( TC+ TD)-1 Oscillator simplified circuit. 1 2 Rt 3 4 COMP Vref FB Vcc Isense OUT R/C GND 8 7 6 5 Ct © Copyright 2010- ASIC Advantage, Inc. – AADS00012 / R127B - Preliminary - October 2010 4/8 Power Management AAC242/243 Dead/delay time verses Ct Delay in µs Rt resistance in KΩ Oscillator Frequency as a function of Rt and Ct Ct Capacitance in nF Oscillator frequency in KHz Peak current is set by the internal comparator with a fixed limit of 0.250V. Raising the current sense pin (3) to 0.250V or higher will cause a termination of the output pulse regardless of the error amplifier output. The peak current is normally determined when the current sense pin exceeds the error amplifier conditioned output. Peak current is determined by the formula: ISENSE(PK) = 0.250V/RS In some cases where leading edge switching transients exceed the 100ns blanking, a small RC filter will be required. RC filter 1 2 3 R Rsense © Copyright 2010- ASIC Advantage, Inc. – C 4 COMP Vref FB Vcc Isense OUT R/C GND AADS00012 / R127B - 8 7 6 5 Preliminary - October 2010 5/8 Power Management AAC242/243 In cases where duty cycle exceeds 50% slope compensation is required. This can be implemented by adding a buffer transistor to the oscillator circuit and using a resistive summing circuit to provide the ramp necessary for slope compensation. Slope compensation Rt 2N3904 1 Rslope 2 3 R Rsense 4 C COMP Vref FB Vcc Isense OUT R/C GND 8 7 6 5 Ct Shut down circuits depend on the desired function. A transistor can be used to allow control on and off of the PWM or an SCR can be used to latch off the PWM. Shutdown circuits 100K 1 2 3 4 shutdown COMP Vref FB Vcc Isense OUT R/C GND 100K 8 7 2 6 3 5 4 shutdown COMP Vref FB Vcc Isense OUT R/C GND 8 7 6 5 2N3904 2N3904 © Copyright 2010- ASIC Advantage, Inc. 1 – AADS00012 / R127B - Preliminary - October 2010 6/8 Power Management AAC242/243 Ordering Information Ordering PN(1) AAC242E‐D8A‐G‐LF Subgroup Controller Description Current Mode, Offline Thresholds Temp. Range Ext. Industrial Package 8‐Pin DIP Packing Type Tube AAC242A‐D8A‐G‐LF Controller AAC242E‐S8A‐G‐LF Packing Qty 50 Current Mode, Offline Thresholds Automotive 8‐Pin DIP Tube 50 Controller Current Mode, Offline Thresholds Ext. Industrial 8‐Pin SOIC Tube 98 AAC242E‐S8A‐G‐LF‐TR Controller Current Mode, Offline Thresholds Ext. Industrial 8‐Pin SOIC 13” T&R (2) 2500 AAC242A‐S8A‐G‐LF Controller Current Mode, Offline Thresholds Automotive 8‐Pin SOIC Tube 98 AAC242A‐S8A‐G‐LF‐TR Controller Current Mode, Offline Thresholds Automotive 8‐Pin SOIC 13” T&R (2) 2500 AAC242E‐F8A‐G‐LF‐W Controller Current Mode, Offline Thresholds Ext. Industrial 3mmx3mm 8‐Pin DFN Waffle Pack TBD AC242E‐F8A‐G‐LF‐TR Controller Current Mode, Offline Thresholds Ext. Industrial 3mmx3mm 8‐Pin DFN T&R (2) TBD AAC242A‐F8A‐G‐LF‐W Controller Current Mode, Offline Thresholds Automotive 3mmx3mm 8‐Pin DFN Waffle Pack TBD AC242A‐F8A‐G‐LF‐TR Controller Current Mode, Offline Thresholds Automotive 3mmx3mm 8‐Pin DFN T&R (2) TBD AAC243E‐D8A‐G‐LF Controller Current Mode, Battery Level Thresholds Ext. Industrial 8‐Pin DIP Tube 50 AAC243A‐D8A‐G‐LF Controller Current Mode, Battery Level Thresholds Automotive 8‐Pin DIP Tube 50 AAC243E‐S8A‐G‐LF Controller Current Mode, Battery Level Thresholds Ext. Industrial 8‐Pin SOIC Tube 98 AAC243E‐S8A‐G‐LF‐TR Controller Current Mode, Battery Level Thresholds Ext. Industrial 8‐Pin SOIC 13” T&R (2) 2500 AAC243A‐S8A‐G‐LF Controller Current Mode, Battery Level Thresholds Automotive 8‐Pin SOIC Tube 98 AAC243A‐S8A‐G‐LF‐TR Controller Current Mode, Battery Level Thresholds Automotive 8‐Pin SOIC 13” T&R (2) 2500 AC243E‐F8A‐G‐LF‐W Controller Current Mode, Battery Level Thresholds Ext. Industrial 3mmx3mm 8‐Pin DFN Waffle Pack TBD AAC243E‐F8A‐G‐LF‐TR Controller Current Mode, Battery Level Thresholds Ext. Industrial 3mmx3mm 8‐Pin DFN T&R (2) TBD AC243A‐F8A‐G‐LF‐W Controller Current Mode, Battery Level Thresholds Automotive 3mmx3mm 8‐Pin DFN Waffle Pack TBD AAC243A‐F8A‐G‐LF‐TR Controller Current Mode, Battery Level Thresholds Automotive 3mmx3mm 8‐Pin DFN T&R (2) TBD (1) Only RoHS/Lead‐Free Packaging is normally offered. (2) T&R ‐ Tape and Reel Package Dimensions and Marking The AAC242 and AAC243 are available in a plastic 8-pin DIP or SOIC package. Refer to the latest version of specification AAPS001 (ASIC Advantage’s “Package Numbering, Marking, and Outline Standard”, available at www.asicadvantage.com) for specific information concerning the package dimensions and package marking. © Copyright 2010- ASIC Advantage, Inc. – AADS00012 / R127B - Preliminary - October 2010 7/8 Power Management AAC242/243 The following is a brief overview of certain terms and conditions of sale of product. For a full and complete copy of all the General Terms and Conditions of Sale, visit our webpage http://www.asicadvantage.com/terms.htm. LIMITED WARRANTY The product is warranted that it will conform to the applicable specifications and be free of defects for one year. Buyer is responsible for selection of, use of and results obtained from use of the product. Buyer indemnifies and holds ASIC Advantage, Inc. harmless for claims arising out of the application of ASIC Advantage, Inc.’s products to Buyer’s designs. 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