MIC2194YM Microchip

MIC2194 Micrel MIC2194 400kHz SO-8 Buck Control IC General Description Features Micrels MIC2194 is a high efficiency PWM buck control IC 2.9V to 14V input voltage range housed in the SO-8 package. Its 2.9V to 14V input voltage 400kHz oscillator frequency range allows it to efficiently step down voltages in 3.3V, 5V, PWM current mode control and 12V systems as well as 1- or 2-cell Li Ion battery powered 2 output drivers applications. The flexible architecture of the MIC2194 allows 100% maximum duty cycle for it to be configured as a buck or a buck-boost converter. 0.5 A micro-power shutdown Programmable UVLO The MIC2194 solution saves valuable board space. The Front edge blanking device is housed in the space-saving SO-8 package, whose Cycle-by-cycle current limiting low pin-count minimizes external components. Its 400kHz Frequency foldback short circuit protection PWM operation allows a small inductor and small output 8-lead SOIC package capacitors to be used. The MIC2194 can implement all- ceramic capacitor solutions. Applications The MIC2194 drives a high-side P-channel MOSFET. A low Point of load power supplies output driver impedance of 2 allows the MIC2194 to drive Negative voltage buck-boost power supplies large external MOSFETs to generate a wide range of output Distributed power systems currents. The MIC2194 can achieve maximum duty cycles of Base stations 100%, which can be useful in low headroom applications. Wireless modems The MIC2194 is available in an 8 pin SOIC package with a ADSL line cards junction temperature range of 40C to +125C. Servers Step down conversion in 3.3V, 5V, 12V systems 1-and 2-cell Li Ion battery operated equipment Typical Application V IN 12V 0.012 47 F MIC2194BM Si4431A 20V (2) VIN CS (2) V OUT EN/ OUTP 5.2 H 5V, 5A UVLO VDD FB 10k B530 1 F 2k COMP GND 220 F 2.2nF 10V 3.32k (2) Adjustable Output Buck Converter V IN +3.3V 22 H 0.040 Si9803 10 F MIC2194BM 16V 22nF VIN CS B530 EN/ OUTP 220 F 3.01k UVLO 10 F 10V 16V (2) VDD FB 1 F 4.99k 1k COMP GND 10nF V OUT 5V, 0.6A Positive-to-Negative Buck-Boost Converter Micrel, Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 MIC2194 Micrel Ordering Information Part Number Standard Lead-Free Output Voltage Frequency Junction Temp. Range Package MIC2194BM MIC2194YM Adjustable 400kHz 40C to +125C 8-lead SOP Pin Configuration COMP 1 8 VIN FB 2 7 OUTP EN/UVLO 3 6 GND CS 4 5 VDD 8 Lead SOIC (M) Pin Description Pin Number Pin Name Pin Function 1 COMP Compensation (Output): Internal error amplifier output. Connect to a capacitor or series RC network to compensate the regulators control loop. 2 FB Feedback (Input): The circuit regulates this pin to 1.245V. 3 EN/UVLO Enable/Undervoltage Lockout (Input): A low level on this pin will power down the device, reducing the quiescent current to under 0.5 A. This pin has two separate thresholds, below 1.5V the output switching is disabled, and below 0.9V the device is forced into a complete micropower shutdown. The 1.5V threshold functions as an accurate undervoltage lockout (UVLO) with hysteresis. 4 CS The () input to the current limit comparator. A built-in offset of 110mV between VIN and CSL in conjunction with the current sense resistor sets the current limit threshold level. This is also the () input to the current amplifier. 5 VDD 3V internal linear-regulator output. VDD is also the supply voltage bus for the chip. Bypass to GND with 1 F. 6 GND Ground. 7 OUTP High current drive for the synchronous N-channel MOSFET. Voltage swing is from ground to VIN. On-resistance is typically 3 5V . IN 8 VIN Input voltage to the circuit. Also the high side input to the current sense amplifier supplies power to the gate drive circuit. MIC2194 2 April 2005