MIC2169 Micrel MIC2169 500kHz PWM Synchronous Buck Control IC General Description Features The MIC2169 is a high-ef ciency, simple to use 500kHz PWM 3V to 14.5V input voltage range synchronous buck control IC housed in a small MSOP-10 Adjustable output voltage down to 0.8V package. The MIC2169 allows compact DC/DC solutions Up to 95% ef ciency with a minimal external component count and cost. 500kHz PWM operation Adjustable current limit senses high-side N-Channel The MIC2169 operates using a 3V to 14.5V input, without MOSFET current the need for any additional bias voltage. The output voltage No external current-sense resistor can be precisely regulated down to 0.8V. The adaptive all Adaptive gate drive increases ef ciency N-Channel MOSFET drive scheme allows ef ciencies, over Fast transient response 95%, across a wide load range. Externally compensated The MIC2169 senses current across the high-side N-Channel Overvoltage protection protects the load in fault MOSFET, eliminating the need for an expensive and lossy conditions current-sense resistor. Current limit accuracy is maintained Dual mode current limit speeds up recovery time via a positive temperature coef cient that tracks the increas- Hiccup mode short-circuit protection ing R of the external MOSFET. Additional cost and DS(ON) Small size MSOP 10-lead package space are saved by the internal in-rush-current limiting and digital soft-start. Applications The MIC2169 is available in a 10-pin MSOP package, with a Point-of-load DC/DC conversion wide junction operating range of 40C to +125C. Set-top boxes Graphic cards All support documentation can be found on Micrels web site LCD power supplies at: www.micrel.com. Telecom power supplies Networking power supplies Cable modems and routers Typical Application V = 5V IN SD103BWS MIC2169 Efficiency 100F 100 95 4.7F 90 0.1F 85 VDD BST 1k 80 CS 75 IRF7821 VIN HSD MIC2169 2.5H 3.3V 70 VSW 65 COMP/EN 10k IRF7821 V = 5V 150pF 100nF LSD 60 IN 150F x 2 V = 3.3V 55 OUT FB 4k GND 3.24k 50 0246 8 10 12 14 16 I (A) LOAD MIC2169 Adjustable Output 500kHz Converter Micrel, Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 MIC2169 Micrel Ordering Information Part Number Pb-Free Part Number Frequency Junction Temp. Range Package MIC2169BMM MIC2169YMM 500kHz 40C to +125C 10-lead MSOP Pin Con guration VIN 1 10 BST VDD 2 9 HSD CS 3 8 VSW COMP 4 7 LSD FB 5 6 GND 10-Pin MSOP (MM) Pin Description Pin Number Pin Name Pin Function 1 VIN Supply Voltage (Input): 3V to 14.5V. 2 VDD 5V Internal Linear Regulator (Output): V is the external MOSFET gate DD drive supply voltage and an internal supply bus for the IC. When V is <5V, IN this regulator operates in dropout mode. 3 CS Current Sense (Input): Current-limit comparator noninverting input. The cur- rent limit is sensed across the MOSFET during the ON time. The current can be set by the resistor in series with the CS pin. 4 COMP Compensation (Input): Pin for external compensation 5 FB Feedback (Input): Input to error ampli er. Regulates error ampli er to 0.8V. 6 GND Ground (Return). 7 LSD Low-Side Drive (Output): High-current driver output for external synchro- nous MOSFET. 8 VSW Switch (Return): High-side MOSFET driver return. 9 HSD High-Side Drive (Output): High-current output-driver for the high-side MOS- FET. When V is between 3.0V to 5V, 2.5V threshold MOSFETs should be IN used. At V > 5V, 5V threshold MOSFETs should be used. IN 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 IN diode drop. M9999-032409 2 March 2009