MIC2165 Adaptive On-Time DC-DC Controller Featuring HyperLight Load Hyper Speed Control Family General Description Features The Micrel MIC2165 is a synchronous adaptive on-time Hyper Speed Control architecture enables buck controller targeting high-performance, cost-sensitive High V Low V operation (V =28V & V =0.8V) IN OUT IN OUT applications such as set-top boxes, gateways, routers, Small output capacitance computing peripherals, and telecom/networking HyperLight Load Efficiency equipment. Built-in 5V regulator for single-supply operation TM The MIC2165 operates over a supply range of 4.5V to Any Capacitor stable 28V. It has an internal linear regulator which provides a - Zero ESR to high ESR regulated 5V supply to power the internal control circuitry. Power-Good output MIC2165 operates at a constant 600kHz switching Input voltage range: 4.5V to 28V frequency and can be used to drive up to 25A of output 5 A typical shutdown current current. The output voltage is adjustable from 0.8V to 25A output current drive capability 5.5V. Adjustable output from 0.8V to 5.5V with 1% FB A unique Hyper Speed Control architecture enables Accuracy ultra-fast transient response while reducing the output 600kHz switching frequency capacitance and also makes High V /Low V operation IN OUT Internal 5ms digital Soft Start possible. Thermal shutdown and hiccup current-limit protection A UVLO feature is provided to ensure proper operation No external current-sense resistor required under power-sag conditions to prevent the external power Safe start-up into pre-biased loads MOSFET from over heating. Also, a soft start feature is 10-pin MSOP ePad package provided to reduce the inrush current. Short current 40 C to +125 C junction temperature range sensing on the bottom MOSFET with hiccup mode current limiting ensures protection in case of an output short Applications circuit. Further, the MIC2165 includes an EN pin to shut Set-top box, gateways, routers and DSL modems down the converter and a Power Good (PGOOD) pin to Printers, scanners, graphic and video cards allow simple sequencing. Servers, PCs and processor core supply The MIC2165 is available in a 10-pin MSOP ePad Low-Voltage Distributed Power package with a junction operating temperature ranging from 40C to +125C. All support documentation can be found on Micrels web site at: www.micrel.com. Typical Application 12V to 3.3V Efficiency 100 90 80 70 60 50 40 30 20 10 0 0.01 0.10 1.00 10.00 OUTPUT CURRENT (A) MIC2165 Adjustable Output 600kHz Buck Converter MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. HyperLight Load is a registered trademark of Micrel, Inc. Hyper Speed Control and Any Capacitor are trademarks of Micrel, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC2165 Ordering Information Part Number Voltage Switching Frequency Junction Temp. Range Package Lead Finish MIC2165YMME Adj. 600kHz 40 to +125C 10-pin ePad MSOP Pb-Free Pin Configuration 10-Pin ePad MSOP (MME) Pin Description Pin Pin Name Pin Function Number Feedback (Input): Input to the transconductance amplifier of the control loop. The FB pin is regulated to 1 FB 0.8V. A resistor divider connecting the output to FB is used to set the desired output voltage. Power Good (Output): Open Drain Output. The PGOOD pin is externally tied with a resistor to VDD. 2 PGOOD High output when V >90% nominal. OUT Enable (Input): A logic level control of the output. The EN pin is CMOS-compatible. Logic high = enable, 3 logic low = shutdown. In the off state, supply current of the device is greatly reduced (typically 5A). The EN EN pin should not be left open. Connect to VIN if sequencing not required. Supply Voltage: Input voltage for the internal +5V linear regulator. The VIN operating voltage range is 4 VIN from 4.5V to 28V. A 0.1F capacitor between VIN and the ground is required. 5V Internal Linear Regulator (Output): VDD is the external MOSFET gate drive supply voltage and an VDD internal supply bus for the IC. VDD is created by internal LDO from VIN. When VIN <+5.5V, VDD Should 5 be tied to VIN. A 2.2F (minimum) ceramic capacitor from VDD to GND is recommended for clean operation. Low-Side Gate Drive (Output): High-current driver output for external low-side MOSFET. The DL driving 6 DL voltage swings from ground to VDD. Power Ground. PGND is the ground path for the MIC2165 buck converter power stage. The PGND pin connects to the sources of low-side N-Channel MOSFETs, the negative terminals of input capacitors, 7 PGND and the negative terminals of output capacitors. The loop for the power ground should be as small as possible and separate from the Signal ground (GND) loop. High-Side Gate Drive (Output): High-current driver output for external high-side MOSFET. The DH 8 DH driving voltage is floating on the switch node voltage (SW). It swings from ground-to-VDD minus the diode drop. Switch Node (Input): High current output driver return. The SW pin connects directly to the switch node. Due to the high speed switching on this pin, the SW pin should be routed away from sensitive nodes. Current-Sense Input (Input): SW pin also senses the current by monitoring the voltage across the low- 9 SW side MOSFET during OFF-time. The current sensing is necessary for short circuit protection and zero current cross comparator. In order to sense the current accurately, connect the low-side MOSFET drain to SW using a Kelvin connection. Boost (Output): Bootstrapped voltage to the high-side N-channel MOSFET driver. A Schottky diode is connected between the VDD pin and the BST pin. A boost capacitor of 0.1F is connected between the 10 BST BST pin and the SW pin. Adding a small resistor at BST pin can slow down the turn-on time of high-side N-Channel MOSFETs. Thermal Pad and Signal ground. GND is the ground path for VDD and the control circuitry. The loop for EP GND the signal ground should be separate from the power ground (PGND) loop. 2 September 2010 M9999-092410-E