MIC2159 SYNCHRONOUS-itty Step-Down Converter IC General Description Features The MIC2159 is a high efficiency, simple to use Small footprint 10-lead ePAD MSOP synchronous buck controller ICs housed in a 10-pin MSOP 3V to 14.5V input voltage range ePAD package. The MIC2159 switches at 400kHz, Adjustable output voltage down to 0.8V allowing the smallest possible external components and is 400KHz operation designed to drive loads up to 30A. The devices feature high output driver capability, combined with an all n- Drives two n-channel MOSFETs channel synchronous architecture. - Built-in 3 drivers The MIC2159 operates from a 3V to 14.5V input and can Simple control: voltage-mode PWM be configured to generate output voltages as low as 0.8V. Fast transient response Efficiencies of over 95% can be achieved within the - Externally compensated smallest possible printed circuit board space area. Over-current protection The MIC2159 is available in a thermally capable 10-pin Hiccup mode short-circuit protection ePAD MSOP package, with a junction operating range from 40C to +125C. Dual function COMP & EN pin - I = 50A SD Short minimum ON time - 30ns - Very low duty cycle possible Applications Point-of-Load DC/DC conversion High Current Power Supplies Telecom/datacom and Networking Power Supplies Servers and Workstations Graphics Cards and other PC Peripherals Typical Application MIC2159 Adjustable Output 400kHz Converter MLF and MicroLead Frame is a registered trademark of Amkor Technology, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC2159 Ordering Information Part Number Output Voltage Frequency Juction Temperature Range Package 10-pin ePAD MSOP MIC2159YMME Adj 400KHz -40C to +125C Pin Configuration 10-lead e-PAD MSOP (MME) Pin Description Pin Number Pin Name Pin Function (MSOP-10) 1 V Supply voltage (Input): 3V to 14.5V IN 2 V 5V Internal Linear Regulator (Output): V is the external MOSFET gate drive supply voltage DD DD and an internal supply bus for the IC. When Vin is 5V, V should be connected to Vin. DD 3 CS Current Sense. Current-limit comparator non-inverting input. The current limit is sensed across the FET during the ON time. The current can be set by the resistor in series with the CS pin. 4 COMP/EN Compensation (Input): Dual function pin. Pin for external compensation. If this pin is pulled below 0.2V, with the reference fully up the device shuts down (50A typical current draw) 5 FB Feedback (Input): Input to error amplifier. Regulates error amplifier to 0.8V. 6 GND Ground (Return) 7 LSD Low-Side Drive (Output): High-current driver output for external synchronous MOSFET. 8 VSW Switch (Return): High-side MOSFET driver return 9 HSD High-Side Drive (Output): High current output-driver for the high-side MOSFET. When Vin is below 5v, 2.5v threshold FETs should be used. At Vin > 5V, 4.5V threshold FETs should be used. 10 BST Boost (Input): Provides the drive voltage for the high-side MOSFET driver. The gate drive voltage is higher than the source voltage by V minus a diode drop. IN March 2009 2 M9999-030509-B