AT1604 5-Bit Synchronous-Rectifier PWM Controller Features General Description ˙Drives two N-channel MOSFETs ˙Operates from +5V and +12V input ˙Simple single-loop control -Voltage-mode PWM control ˙Fast transient response - High-bandwidth error amplifier - Full 0% to 100% duty ratio ˙Excellent output voltage regulation - ± 1% over line voltage and temperature ˙TTL-compatible 5 bit digital-to-analog output voltage selection - Wide range 1.3VDc to 3.5VDC - 0.1V binary steps from 2.1VDC to 3.5VDC - 0.05V binary steps from 1.3VDC to 2.05VDC ˙Power-good output voltage monitor ˙Over-voltage and over-current fault monitors -Does not require extra current sensing element ˙Small converter size -Constant frequency operation -200 kHz free-running oscillator programmable from 50 kHz to over 1 MHz The AT1604 provides complete control and protection for a DC-DC converter optimized for high-performance microprocessor applications. It is designed to drive two N-channel MOSFETs in a synchronous-rectified buck topology. The AT1604 integrates all of the control, output adjustment, monitoring and protection functions into a single package. Applications ˙Power supply for PentiumTM, PentiumTM Pro, PowerPCTM and AlphaTM Microprocessors ˙High-power 5V to 3.xV DC-DC regulators ˙Low-voltage distributed power supplies The AT1604 includes a fully-TTL compatible 5-bit digital-to-analog converter (DAC) that adjusts the output voltage from 2.1VDC to 3.5VDC in 0.1V increments and from 1.3VDC to 2.1VDC in 0.05V steps. The precision reference and voltage–mode regulator hold the selected output voltage to within ± 1% over temperature and line voltage variations. The AT1604 provides simple, single feedback loop, voltage-mode control with fast transient response. It includes a 200kHz free-running triangle-wave oscillator that is adjustable from below 50kHz to over 1MHz. The error amplifier features a 12MHz gain-bandwidth product and 6V/μs slew rate which enable high converter bandwidth for fast transient performance. The resulting PWM duty ratio ranges from 0% to 100%. The AT1604 monitors the output voltage with a window comparator that tracks the DAC output and issues a Power Good signal when the output is within ± 10% of the targeted value. The AT1604 protects against over-current conditions by inhibiting PWM operation. Built-in over-voltage protection triggers an external SCR to crowbar the input supply. The AT1604 monitors the current by using the rDS(on) of the upper MOSFET, which eliminates the need for a current sensing resistor. 2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: [email protected] Preview the document, detail datasheet contact to our service department. AT1604 5-Bit Synchronous-Rectifier PWM Controller Block Diagram Pin Configuration AT1604 (20-Pin SOIC) 2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: [email protected] Preview the document, detail datasheet contact to our service department.