AAC243E-S8A-G-LF-TR Microchip

Power Management AAC242/243 AAC242/243 PRELIMINARY DATA Current Mode PWM Contoller DESCRIPTION The AAC242 and AAC243 are part of AAIs 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 FEATURES AAC24X parts in offline applications. Low Start-up current The AAC242 and AAC243 are identical except for the Pulse by pulse current limiting Under Voltage Lockout. The AAC242 has UVLO on On board voltage reference threshold of 16V and off of 10V making it easy to use Under Voltage Lockout with hysteresis in offline supplies where startup requirements for Simple oscillator circuit energy storage is necessary. For applications using lower supply voltages the AAC243 has UVLO of on Over Voltage protection zener 8.4V and UVLO of 7.6V. off High current output driver Less than 30ns rise and fall times The AAC24X family is offered in DIP and SMD Operation to over 1MHz packages. The packages are industry standards and are ROHS compliant. Extended temperature is Peak Current Mode control standard with the AAC24X family. Integrated Soft-Start Function (~330 Clock Cycles) The greater than 1A output driver is ideal for driving 100ns leading edge current blanking for reduced MOSFETs and low power IGBTs. Rise and fall times filtering are typically less that 30ns with a 1000pF load. The 250mV current sense improvements in switching speed can provide improvements in efficiency, higher operating frequency and over current protection. PIN CONFIGURATION: 8-Lead DIP and SOIC8 The AAC24X family has a minimum pulse width of View of the AAC24X shown from the top. 0.4% allowing operation at very low power without pulse skipping or erratic operation. The narrower COMP 1 8 VREF pulse width capibilities enhances operation at higher AAC242 VFB VCC frequencies and voltages. AAC243 ISENSE OUT Rt/Ct 4 5 GND Copyright 2010- ASIC Advantage, Inc. AADS00012 / R127B - Preliminary - October 2010 1 / 8 Power Management AAC242/243 BLOCK DIAGRAM 8 Vcc 5.00VREF UVLO 5V Vref 7 34V REF DVR 5 GND REF 2.5V OSC OK OUTPUT 6 4 Rt/Ct Error Amp 11R 2R + S - - 2 Vf b R Q R 1V + Current Sense 1 COMP Comparator 3 Isense Open Loop Test Circuit A V+ Rt 4.7K 100K 0.1uF 1 8 COMP Vref 2N3904 2 7 FB Vcc 1K 1K/1W 3 6 OUTPUT Isense OUT 4 5 R/C GND 5K 0.1uF 4.7K Ct MAXIMUM RATINGS PARAMETER PARAMETERS UNITS CONDITIONS MIN. MAX. Supply Voltage (V Ground) 0 30 V Low impedance source cc V and I Amp Inputs -0.3 5.5 V fb sense Output Current 1 A 1200 mW DIP Power Dissipation 1000 mW SOIC8 Operating Junction Temperature 150 C Extended industrial temp. rated Operating Ambient Temperature -40 105 C devices Operating Ambient Temperature -40 125 C Automotive temp. rated devices Storage Temperature Range -65 150 C Lead Temperature (10 Second) 300 C Soldering Copyright 2010- ASIC Advantage, Inc. AADS00012 / R127B - Preliminary - October 2010 2 / 8