MPQ2128 2.5V-to-6V Input, 3MHz, 1A Synchronous, Step-Down Converter Available in AEC-Q100 `DESCRIPTION FEATURES The MPQ2128 is a 3MHz, constant-frequency, current-mode, PWM, step-down converter. It has an integrated main switch and synchronous rectifier that make it ideal for low-voltage conversions. • • • • • • • • • • • • • • The MPQ2128 can supply up to 1A load current from a 2.5V-to-6V input voltage. The output voltage can go as low as 0.6V. Additional features include <1μA shutdown current, internal soft-start, cycle-by-cycle overcurrent protection, short-circuit protection, and thermal shutdown. The MPQ2128 is available in a 2mm×2mm 8pin QFN package. Meets Automotive Requirements Highly Efficient: Up to 95% 3MHz Constant-Switching Frequency 1A Available Load Current 2.5V-to-6V Input Voltage Range Output Voltage as Low as 0.6V Current-Mode Control Cycle-by-Cycle Over-Current Protection Short-Circuit Protection Thermal Shutdown <1μA Shutdown Current Internal Soft-Start QFN8 (2mm×2mm) Package AEC-Q100 Qualified APPLICATIONS • Industrial/Automotive All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Products, Quality Assurance page. “MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION MPQ2128 Rev. 1.1 www.MonolithicPower.com 4/1/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 1 MPQ2128 – 3MHz, 1A, SYNCHRONOUS, STEP-DOWN CONVERTER ORDERING INFORMATION Part Number* MPQ2128DG MPQ2128DG-AEC1* Package QFN8 (2mm×2mm) QFN8 (2mm×2mm) Top Marking AY AY * For Tape & Reel, add suffix –Z (eg. MPQ2128DG-Z). For RoHS compliant packaging, add suffix –LF (e.g. MPQ2128DG-LF–Z) PACKAGE REFERENCE QFN8 ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance IN to GND ..................................–0.3V to +6.5V SW to GND .......................... –0.3V to VIN + 0.3V FB, EN to GND.............................–0.3V to +6.5V Continuous Power Dissipation. (TA = +25°C) (2) QFN8 (2mm×2mm) ....................................2.5W Junction Temperature .............................. 150°C Lead Temperature ................................... 260°C Storage Temperature .............. –65°C to +150°C QFN8 (2mmx2mm)................. 50 ...... 12 ... °C/W Recommended Operating Conditions (3) Supply Voltage VIN ............................ 2.5V to 6V Output Voltage VOUT.......................... 0.6V to 6V Operating Junction Temp. ....... –40°C to +125°C (4) θJA θJC Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature TJ (MAX), the junction-toambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD (MAX) = (TJ (MAX)-TA)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7, 4-layer PCB. MPQ2128 Rev. 1.1 www.MonolithicPower.com 4/1/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 2 MPQ2128 – 3MHz, 1A, SYNCHRONOUS, STEP-DOWN CONVERTER ELECTRICAL CHARACTERISTICS (5) VIN = VEN = 3.6V, Tj = -40°C to 125°C, unless otherwise noted. Typical values are at Tj = 25 °C. Parameters Condition Min Supply Current VEN = VIN, VFB = 0.65V Shutdown Current VEN = 0V, VIN = 6V IN Under Voltage Lockout Threshold Rising Edge IN Under Voltage Lockout Hysteresis Tj = +25°C Regulated FB Voltage –40°C ≤ Tj ≤ 125°C FB Input Bias Current VFB = 0.65V PFET Current Limit Duty Cycle ≤ 40% PFET On-Resistance NFET On-Resistance ISW = 100mA ISW = –100mA VEN = 0V; VIN = 6V VSW = 0V or 6V –40°C ≤ TJ ≤125°C –40°C ≤ TJ ≤125°C SW Leakage Current EN High Threshold EN Low Threshold Internal Soft-Start Time Oscillator Frequency Thermal Shutdown Threshold 1.75 0.582 0.574 -200 Tj = 25°C -40°C≤Tj≤125°C Max Units 350 750 μA 0.01 2.1 250 0.594 0.594 1.2 2.3 μA V mV V V nA 0.606 0.614 200 1.8 A 1.2 200 150 –3 mΩ mΩ 3 μA 0.4 V V 1.6 2.2 Hysteresis=20°C Typ 100 2.8 150 3.4 µs MHz °C Note: 5) Production test at +25°C. Specifications over the temperature range are guaranteed by design and characterization. MPQ2128 Rev. 1.1 www.MonolithicPower.com 4/1/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 3 MPQ2128 – 3MHz, 1A, SYNCHRONOUS, STEP-DOWN CONVERTER TYPICAL PERFORMANCE CHARACTERISTICS VIN=6V, VOUT=1.8V, L=1.2µH, C2=10µF, TA=25°C, unless otherwise noted. MPQ2128 Rev. 1.1 www.MonolithicPower.com 4/1/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 4 MPQ2128 – 3MHz, 1A, SYNCHRONOUS, STEP-DOWN CONVERTER PIN FUNCTIONS QFN Pin # Name Description 8 2,4 EN GND Enable. Drive EN above 1.6V to turn on the part. Drive EN below 0.4V to turn it off. Ground. 5,6 SW 3 IN 1 FB Power Switch Output. Connect an inductor to the drains of the internal PFET and NFET switches. Supply. Bypass to GND with a ≥4.7µF ceramic capacitor. Feedback. Connect to the tap of the external resistor divider. The regulated feedback voltage is 0.6V. Exposed Pad BLOCK DIAGRAM Figure 1: Functional Block Diagram MPQ2128 Rev. 1.1 www.MonolithicPower.com 4/1/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 5 MPQ2128 – 3MHz, 1A, SYNCHRONOUS, STEP-DOWN CONVERTER FUNCTIONAL DESCRIPTION MPQ2128 is a 3MHz, constant frequency, current-mode, PWM, step-down converter. The device integrates both a main switch and a synchronous rectifier, which provides high efficiency and eliminates the need for an external Schottky diode. It is ideal for powering portable equipment that runs from a single Li-lon or LiPolymer battery. The MPQ2128 can achieve 100% duty cycle. The duty cycle, D, of the step-down converter is defined as: D =t ON × fOSC × 100% ≈ VOUT × 100% VIN Where, τON: Main Switch ON time fOSC: Switching frequency (3MHz) VOUT: Output voltage VIN: Input voltage Peak-Current –Mode PWM Control Slope-compensated, current-mode, PWM control provides stable switching and cycle-by-cycle current limiting for superior load and line response, and protects the internal main switch and synchronous rectifier. The MPQ2128 switches at a constant frequency (3MHz) and regulates the output voltage. During each cycle the PWM comparator modulates the power transferred to the load by changing the inductor peak current based on the feedback error voltage. current limit. The output voltage is then the difference between the input voltage and the voltage drop across the main switch and the inductor. Short-Circuit Protection The MPQ2128 has short-circuit protection. When the output is shorted to ground, the oscillator frequency reduces to prevent the inductor current from increasing beyond the PFET current limit. The PFET current limit also drops to lower the short-circuit current. The frequency and current limit return to their normal values once the short circuit condition is removed and the feedback voltage reaches 0.6V. Maximum Load Current The MPQ2128 can operate at an input voltage as low as 2.5V. However the maximum load current decreases with the lower input due to a large voltage drop across the main switch and synchronous rectifier. The slope compensation signal reduces the peak inductor current as a function of the duty cycle to prevent subharmonic oscillations at duty cycles greater than 50%. Conversely the current limit increases as the duty cycle decreases. During normal operation, the main switch turnS on to ramp-up the inductor current with each rising edge of the internal oscillator, and switches off when the peak inductor current rises above the error voltage. When the main switch is off, the synchronous rectifier turns on immediately and remains on until the next cycle starts. Dropout Operation The MPQ2128 allows the main switch to remain on for more than one switching cycle and increases the duty cycle while the input voltage drops down to the output voltage. When the duty cycle reaches 100%, the main switch is held ON to deliver current to the output up to the PFET MPQ2128 Rev. 1.1 www.MonolithicPower.com 4/1/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 6 MPQ2128 – 3MHz, 1A, SYNCHRONOUS, STEP-DOWN CONVERTER PACKAGE INFORMATION QFN8 (2mm×2mm) NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MPQ2128 Rev. 1.1 www.MonolithicPower.com 4/1/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 7