| AAC1042/1043 and AAC2042/2043 |
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High Voltage Current Mode PWM Controllers The AAC1042/43 and AAC2042/43 are four new High Voltage versions of the AAC142/143 and AAC242/243 controllers from ASIC Advantage, Inc., designed as upgrades on the workhorse UC1/2/3842 and UC1/2/3843 family of Current Mode PWM Controllers, available from various sources. The AAC1042/43 and AAC2042/43 are intended for Offline or DCDC power converter applications, offered as an ongoing expansion in Power Management and other Mixed Signal solutions available from ASIC Advantage, Inc. Features in common with the x842/x843 design include current mode control, pulse-pulse current limiting, undervoltage lockout with hysteresis and an on-board voltage reference. In addition, as with the x842/x843 controllers, the AAC1042 and AAC2042 are differentiated from the AAC1043 and AAC2043 by their undervoltage lockout thresholds. The AAC1042/2042 have turn-on/turn-off thresholds of 16V and 10V respectively, while the AAC1043/2043 thresholds are 8.4V and 7.6V respectively. The AAC1043 and AAC2043 are targeted for battery applications, based on its lower undervoltage and hysteresis levels. The lower V-ILimit options of the AAC2042/43 of 0.25V, as compared to the 1.0V for the AAC1042/43, allows for lower current sense measurements. Other features designed into this family of Current Mode Controllers are intended to enhance their functionality and range of use. The maximum Start-Up current is substantially lower than the x842/x843. Output drive rise and fall times of 50ns for the AAC1042/43 and the AAC2042/43 compare to 150ns maximum rise and fall times for the x842/x843. Other unique features of the AAC1042/43 and AAC2042/43 include an integrated soft-start function tied to the clock of the internal oscillator (approximately 330 cycles), leading edge current blanking of 100ns and a more robust, higher current MOS output drive stage capable of driving much higher source and sink currents. The enhancements in drive capability, as well as rise and fall times, enable the AAC1042/43 and AAC2042/43 to operate up to 1MHz vs. the 500kHz maximum typically ascribed for the x842/843. The AAC1042/43 and AAC2042/43 are offered in an RoHS compliant 4.0mm by 7.5mm Voltage Enhanced QFN package with a rated operating temperature range of Extended Industrial (-40°C to +105°C) available. An evaluation board, the AAEV1042, AAEV1043, AAEV2042 or AAEV2043, are available for evaluation of the AAC1042, AAC1043, AAC2042 or AAC2043 respectively. Features 
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