MIC2178 2.5A Synchronous Buck Regulator Features General Description Input Voltage Range: +4.5V to +16.5V The MIC2178 is a 200kHz synchronous buck (step-down) switching regulator designed for Dual-Mode Operation for High Efficiency (up to high-efficiency, battery-powered applications. 96%): - PWM Mode for >200 mA Load Current The MIC2178 operates from a 4.5V to 16.5V input and features internal power MOSFETs that can supply up to - Skip Mode for <200 mA Load Current 2.5A output current. It can operate with a maximum 100 m Internal Power MOSFETs at 12V Input duty cycle of 100% for use in low-dropout conditions. It 200 kHz Preset Switching Frequency also features a shutdown mode that reduces quiescent Low Quiescent Current current to less than 5 A. - 1.0 mA in PWM Mode The MIC2178 achieves high efficiency over a wide - 600 A in Skip Mode output current range by operating in either PWM or skip -< 5 A in Shutdown Mode mode. The operating mode is externally selected, typically by an intelligent system, which chooses the Current-Mode Control appropriate mode according to operating conditions, - Simplified Loop Compensation efficiency, and noise requirements. The switching - Superior Line Regulation frequency is preset to 200kHz and can be 100% Duty Cycle for Low Dropout Operation synchronized to an external clock signal of up to Current Limit 300 kHz. Thermal Shutdown The MIC2178 uses current-mode control with internal Undervoltage Lockout current sensing. Current-mode control provides superior line regulation and makes the regulator control Applications loop easy to compensate. The output is protected with pulse-by-pulse current limiting and thermal shutdown. High-Efficiency, Battery-Powered Supplies Undervoltage lockout turns the output off when the Buck (Step-Down) DC/DC Converters input voltage is less than 4.5V. Palmtop Computers The MIC2178 is packaged in a 20-lead wide power Laptop Computers SOIC package with an operating temperature range of Cellular Telephones -40C to +85C. Handheld Instruments See the MIC2177 for automatic selection of PWM or Battery Chargers skip mode operation. Package Type MIC2178 20-Lead Wide SOIC (WM) (Top View) VIN 1 20 EN VIN 2 19 BIAS SW 3 18 SYNC PGND 4 17 SGND PGND 5 16 SGND PGND 6 15 SGND PGND 7 14 SGND SW 8 13 COMP VIN 9 12 FB 10 11 PWM PWRGD 2021 Microchip Technology Inc. DS20006283B-page 1MIC2178 Typical Application Circuit V IN 5.4V to 16.5V C2 C1 22F ON 22F ENABLE 1,2,9 35V U1 35V OFF VIN R1 20 10 20k V EN OUT OUT L1, 33H 5V/2.5A 11 3,8 Ouput Good PWRGD Output Low SW D1 MIC2178-5.0 Skip Mode 10 47 MBRS140 C5 C6 PWM Mode PGND PWM 220F 220F 18 12 10V 10V SYNC FB COMP SGND BIAS 13 1417 19 R1 C4 10k R2 0.01F 10k C3 6.8nF Functional Block Diagram V IN 4.5V to 16.5V 100F VIN 1 2 9 UVLO, Thermal R1 Shutdown 100m V 1.245 1 OUT P-channel R2 Output I SW SENSE Control 3 L V Amp. OUT Logic EN Enable 3.3V 8 Shutdown 20 Regulator D C OUT BIAS 100m 19 PGND N-channel 10k 0.01F 4 internal 5 * I LIMIT supply Voltage 6 Comp. * Connect 7 PWM PWM/ S to P Skip Mode GND GND Skip-Mode I PWM Mode LIMIT 10 Select Thresh. Voltage Bold lines indicate high current traces Corrective Ramp SYNC Stop 200kHz 18 Oscillator R1 Skip-Mode Reset Pulse Comp. FB R 12 Q R2 S V IN Power Good 20k Comp. PWM PWRGD Output Good Comp. 11 R C COMP 13 C 1.13V C V 1.245V REF MIC2178 Adjustable SGND 14 15 16 17 DS20006283B-page 2 2021 Microchip Technology Inc.