A Product Line of Diodes Incorporated AP3585A/B/C SINGLE PHASE SYNCHRONOUS BUCK PWM CONTROLLER Description Pin Assignments The AP3585A/B/C is a compact synchronous-rectified buck controller (Top View) specifically designed to operate from 4.5V to 13.2V supply voltage and deliver high-quality output voltage as low as 0.8V (AP3585A) or 0.6V (AP3585B/C). This SO-8EP device operates at fixed 1 8 PHASE BOOT 300kHz/200kHz frequency and provides an optimal level of integration to reduce size and cost of the power supply. 2 7 UGATE COMP/EN This controller integrates internal MOSFET drivers that support 3 6 FB GND 12V+12V bootstrapped voltage for high- efficiency power conversion. The bootstrap diode is built-in to simplify the circuit design and 5 LGATE/OCSET 4 VCC minimize external part count. This controller provides single feedback loop, voltage-mode control with fast transient response. The error amplifier features a 10MHz (SO-8/ M Package) gain-bandwidth product and 6V/ s slew rate which enables high converter bandwidth for fast transient performance. (Top View) Other features include internal soft-start, under voltage protection, over current protection and shutdown function. With afore mentioned functions, this part provides customers a compact, high efficiency, BOOT 1 8 PHASE well-protected and cost-effective solution. UGATE 2 Exposed 7 COMP/EN The AP3585A/B/C is available in SO-8 and SO-8EP packages. Pad FB GND 3 6 9 Features 5 VCC LGATE/OCSET 4 Supply Voltage: 4.5V to 13.2V V Input Range: 3.3V to 12V IN (SO-8EP/ MP Package) 0.8V/0.6V to 80% of V Output Range IN Internal Reference: 0.8V/0.6V Simple Single-loop Control Voltage-mode PWM Control Applications Duty Cycle: 0% to 80% Fast Transient Response Subsystem Power Supplies 10MHz High-bandwidth Error Amplifier with 6V/ s Slew Rate PCI, AGP, Graphics Cards, Digital TV Fixed Oscillator Frequency: 300kHz/200kHz SSTL-2 and DDR/2/3 SDRAM Bus Termination Supply Lossless, Programmable Over Current Protection Cable Modems, Set Top Boxes, and DSL Modems (Uses Lower MOSFET R ) DS(ON) Industrial Power Supplies and General Purpose Supplies Start-up into Pre-biased Load Built-in Thermal Shutdown Built-in Soft-start Over Current Protection Over Voltage Protection Under Voltage Protection Integrated Boot Diode Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. Green Device (Note 3) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See A Product Line of Diodes Incorporated AP3585A/B/C Typical Applications Circuit Pin Descriptions Pin Number Pin Name Function SO-8 SO-8EP Bootstrap pin. Connect a bootstrap capacitor from this pin to PHASE for 1 1 BOOT creating a BOOT voltage suitable to drive a standard N-Channel MOSFET. Upper-gate drive pin. Connect this pin to the upper MOSFET gate providing the gate drive. This pin is monitored by the adaptive shoot- 2 2 UGATE through protection circuitry to determine when the upper MOSFET has turned off. Ground for the IC. All voltage levels are measured with respect to this pin. Connect this pin directly to the low side MOSFET source and ground 3 3 GND plane with the lowest impedance. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Low-side Gate Driver Output and Over-Current Setting Input. This pin is 4 4 LGATE/OCSET the gate driver for low-side MOSFET. It is also used to set the maximum inductor current. Refer to the section in Function Description for detail. Bias supply pin. Provides a 4.5V to 13.2V bias supply for the chip from this 5 5 VCC pin. The pin should be bypassed with a capacitor to GND. Feedback pin. This pin is the inverting input of the internal error amplifier. Use FB pin, in combination with the COMP pin, to compensate the voltage 6 6 FB control feedback loop of the converter. A resistor divider from output to GND is used to set the output voltage. Compensation and disable pin. This pin is the output of the Error Amplifier. 7 7 COMP/EN Pull COMP pin low will shut down the IC. This pin connects to the source of the upper MOSFET and the drain of the 8 8 PHASE lower MOSFET. This pin is also monitored by the adaptive shoot-through protection circuitry to determine when the upper MOSFET has turned off. 9 Exposed Pad Exposed Pad as ground pin. 2 of 18 January 2014 AP3585A/B/C Diodes Incorporated www.diodes.com Document number: DS36819 Rev. 1 - 2 NEW PRODUCT