MIC2127A 75V, Synchronous Buck Controller Featuring Adaptive On-Time Control Features General Description Hyper Speed Control Architecture Enables: The MIC2127A is a constant-frequency synchronous buck controller featuring a unique adaptive on-time - High Input to Output Voltage Conversion control architecture. The MIC2127A operates over an Ratio Capability input voltage range from 4.5V-75V. The output voltage - Any Capacitor Stable is adjustable down to 0.6V with an accuracy of 1%. - Ultra-Fast Load Transient Response The device operates with programmable switching Wide 4.5V-75V Input Voltage Range frequency from 270 kHz-800 kHz. Adjustable Output Voltage from 0.6V to 30V The MIC2127A features a MODE pin that allows the 270 kHz-800 kHz Programmable Switching Fre- user to select either Continuous Conduction mode or quency Hyper Light Load (HLL) mode under light loads. An auxiliary bootstrap LDO improves the system efficiency Built-In 5V Regulator for Single-Supply Operation by supplying the MIC2127A internal circuit bias power Auxiliary Bootstrap LDO for Improving System and gate drivers from the output of the converter. A Efficiency logic level enable (EN) signal can be used to enable or Internal Bootstrap Diode disable the controller. The MIC2127A can start-up Selectable Light Load Operating Mode monotonically into a prebiased output. The MIC2127A Enable Input and Power Good Output features an open drain power good signal (PG) that Programmable Current Limit signals when the output is in regulation and can be used for simple power supply sequencing. Hiccup Mode Short-Circuit Protection The MIC2127A offers a full suite of protection features Soft Start, Internal Compensation and Thermal to ensure protection of the IC during Fault conditions. Shutdown These include undervoltage lockout to ensure proper Supports Safe Start-Up into a Prebiased Output operation under power-sag conditions, hiccup mode Applications short-circuit protection, internal soft start of 5 ms to reduce inrush current during start-up and thermal shut- Networking/Telecom Equipment down. Base Station, Servers The MIC2127A is available in a 16-pin 3 mm x 3 mm Distributed Power Systems VQFN package, with an operating junction temperature Industrial Power Supplies range from 40C to +125C. Typical Application P VIN V VDD IN * 4.5V to 75V 4.7 F 0.1 F 2.2 FX3 Q1 DH 10 BST L1 VDD 0.1 F 10 H V OUT 4.7 F SW 5V 5A C1 MIC2127A + 330 F 47 F ILIM 1.3 k 0.1 F PG Q2 DL 7.5 k 4.7 nF V EN IN 36 k V DD MODE FB 1 k 100 k EXTVDD V OUT FREQ V IN 1 F AGND PGND 60 k Q1,Q3: SiR878ADP L1: SRP1265A-100M, Bourns C1: 10SVP330M *Output voltage follows input voltage when the input is below the target output voltage 2016 Microchip Technology Inc. DS20005676B-page 1MIC2127A Package Types MIC2127A 3x 3VQFN* (Top View) 13 16 15 14 PG 1 12 MODE I 11 2 LIM FREQ EP SW 3 10 EN BST 4 9 EXTVDD 56 7 8 * Includes Exposed Thermal Pad (EP) see Table 3-1. Functional Block Diagram P V V EXTVDD VDD EN IN DD 9 8 10 15 16 LINEAR LINEAR UVLO REGULATOR REGULATOR 4 BST THERMAL SHUTDOWN 5 DH MODE 12 Control T ON 11 Zero Crossing FREQ Logic ESTIMATION Detection (ZCD) and 3 SW Negative Current Limit COMPENSATION PVDD 13 FB g m 7 DL Soft CURRENT V REF 100 A Start LIMIT 0.6V DETECTION 2 I LIM PG 1 0.9 VREF 6 P GND FB 14 AGND DS20005676B-page 2 2016 Microchip Technology Inc. DH V IN P V GND DD DL A GND FB P VDD