MPQ8612

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High Efficiency, 12A/16A/20A, 6V Synchronous Step-down Converter MPQ8612 Rev. 1.21 www.MonolithicPower.com 1 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. The Future of Analog IC Technology

DESCRIPTION

The MPQ8612 is fully integrated high frequency synchronous rectified step-down switch mode converter. It offers very compact solutions to achieve 12A/16A/20A output current from a 3V to 6V input with excellent load and line regulation. Constant-On-Time (COT) control mode provides fast transient response and eases loop stabilization. The MPQ8612 can operate with a low-cost electrolytic capacitor and can support ceramic output capacitor with external slope compensation. Operating frequency is programmed by an external resistor and is compensated for variations in V IN. Under voltage lockout is internally set at 2.8 V, but can be increased by programming the threshold with a resistor network on the enable pin. The output voltage startup ramp is controlled by the soft start pin. A power good signal indicates the output is within its nominal voltage range. Full fault protection including OCP, SCP, OVP UVP and OTP is provided by internal comparators. The MPQ8612 requires a minimum number of readily available standard external components and are available in QFN3X4/4X4/4X4 packages.

FEATURES

 1.5V to 6V Wide Input Range  3V to 6V VCC Operating Supply  12A/16A/20A Output Current  Low R DS(ON) Internal Power MOSFETs  Proprietary Switching Loss Reduction Technique  Adaptive COT for Ultrafast Transient Response  1% Reference Voltage Over -20 C to +85C Junction Temperature Range  Programmable Soft Start Time  Pre-Bias Start up  Programmable Switching Frequency from 300kHz to 1MHz.  Minimum On Time T ON_MIN=60ns Minimum Off Time TOFF_MIN=75ns  Non-latch OCP, non-latch OVP Protection and Thermal Shutdown  Output Adjustable from 0.608V to 4.5V

APPLICATIONS

 Telecom System Base Stations  Networking Systems  Server  Personal Video Recorders  Flat Panel Television and Monitors  Distributed Power Systems 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

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 2 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved.

ORDERING INFORMATION

Part Number* Package Top Marking MPQ8612GL-12 QFN (3x4mm) MP8612 MPQ8612GR-16 QFN (4x4mm) MP8612 MPQ8612GR-20 QFN (4x4mm) MP8612 * For Tape & Reel, add suffix –Z (e.g. MPQ8612GL–Z); PACKAGE REFERENCE TOP VIEW 789 101112 13 14 SW SW FREQ IN IN AGND FB SS EN VCC PG BST GND GND EXPOSED PAD ON BACKSIDE Part Number* Package MPQ8612GL-12 QFN14 (3x4mm) *For Tape & Reel, add suffix –Z (eg. MPQ8612GL–12–Z) TOP VIEW 789 1114 15 16SW SW FREQ IN IN AGND FB SS EN VCC PG BST GND GND EXPOSED PAD ON BACKSIDE IN GND 1213 17SW TOP VIEW 789 1114 15 16SW SW FREQ IN IN AGND FB SS EN VCC PG BST GND GND EXPOSED PAD ON BACKSIDE IN GND 1213 17SW Part Number** Package Part Number* Package MPQ8612GR-16 QFN17 (4x4mm) MPQ8612GR-20 QFN17 (4x4mm) For Tape & Reel, add suffix –Z (eg. MPQ8612GR-16–Z) ***For Tape & Reel, add suffix –Z (eg. MPQ8612GR-20–Z)

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 3 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. ABSOLUTE MAXIMUM RATINGS (1) Continuous Power Dissipation (TA=+25) (2)…… Recommended Operating Conditions (3) Operating Junction Temp. (TJ). -40°C to +125°C Thermal Resistance (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 T J(MAX), the junction-to- ambient 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.

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 4 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved.

ELECTRICAL CHARACTERISTICS

VIN = 5V, TJ = -40 to +125C, unless otherwise noted. Parameters Symbol Condition Min Typ Max Units Supply Current Supply Current (Shutdown) I IN V EN = 0V 0.001 2 μA VEN = 2V, VFB = 1V, MPQ8612-12 850 1100 1300 μA Supply Current (Quiescent) I IN VEN = 2V, VFB = 1V, MPQ8612-16, MPQ8612-20 600 1000 1300 μA MOSFET MPQ8612-12, TJ =25C 10 18 MPQ8612-16, TJ =25C 7.4 13 High-side Switch On Resistance HSRDS-ON MPQ8612-20, TJ =25C 6.6 12 mΩ MPQ8612-12, TJ =25C 7.8 10 MPQ8612-16, TJ =25C 5.5 11 Low-side Switch On Resistance LS RDS-ON MPQ8612-20, TJ =25C 4.6 9.5 mΩ Switch Leakage SW LKG VEN = 0V, VSW = 0V or 5V, TJ =25C 0.001 5 μA Current Limit MPQ8612-12 17 21 26 MPQ8612-16 23 28 33 High-side Current Limit I LIMIT MPQ8612-20 29 35 41 A Timer RFREQ=82kΩ,VOUT=1.2V, MPQ8612-12 170 ns One-Shot On Time t ON RFREQ=82kΩ,VOUT=1.2V, MPQ8612-16, MPQ8612-20 200 ns MPQ8612-12 30 75 150 ns Minimum Off Time t OFF MPQ8612-16, MPQ8612-20 30 110 160 ns Fold back Timer(5) t FOLDBACK OCP Happens 2.5 μs Over-voltage and Under-voltage Protection OVP Threshold V OVP1 110 120 130 %V REF OVP Delay(5) t OVP 1 μs UVP Threshold(5) V UVP 50 %V REF

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 5 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. ELECTRICAL CHARACTERISTICS (continued) VIN = 5V, TJ = -40 to +125C, unless otherwise noted. Parameters Symbol Condition Min Typ Max Units Reference And Soft Start TJ = -20C to +85C, MPQ8612-12 602 608 614 TJ = -20C to +85C, MPQ8612-16, MPQ8612-20 604 610 616 TJ = -40C to +125C, MPQ8612-12 599 608 617 Reference Voltage V REF TJ = -40C to +125C, MPQ8612-16, MPQ8612-20 601 610 619 mV Feedback Current I FB V FB = 608mV 0.001 50 nA Soft Start Charging Current I SS V SS=0V 5.5 7.5 9 μA Enable And UVLO Enable Rising Threshold EN Vth-Hi 1.4 1.8 V Enable Hysteresis EN Vth-Hy 890 mV VEN = 2V 1 1.5 2 Enable Input Current I EN VEN = 0V 0.001 μA VCC UVLO VCC Under Voltage Lockout Threshold Rising VCCVth 2.3 2.8 2.95 V VCC Under Voltage Lockout Threshold Hysteresis VCCHYS 300 mV Power Good Power Good Rising Threshold PG Vth-Hi 84 90 96 %V REF Power Good Falling Threshold PG Vth-Lo 63 70 73 %V REF Power Good Deglitch Timer PG Td T SS=1ms, 1.6 2.2 ms Power Good Sink Current Capability VPG Sink 4mA 0.4 V Power Good Leakage Current I PG_LEAK V PG = 3.3V 50 nA Thermal Protection Thermal Shutdown T SD Note 5 150 160 °C Thermal Shutdown Hysteresis 25 °C Note: 5) Guaranteed by design.

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 6 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL CHARACTERISTICS Performance waveforms are tested on the evaluation board of the Design Example section. VIN=5V, VCC=5V, VOUT=1.2V, L=1.0µH, TA=+25°C, unless otherwise noted. 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 -50 -25 0 25 50 75 100 125 150 1000 1050 1100 1150 -50 -25 0 25 50 75 100 125 150 -50 0 50 100 150 -50 0 50 100 150 20.50 20.60 20.70 20.80 20.90 21.00 21.10 21.20 21.30 21.40 21.50 -50 -25 0 25 50 75 100 125 150 146 148 150 152 154 156 158 160 162 -50 -25 0 25 50 75 100 125 150 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 -50 -25 0 25 50 75 100 125 150 27. 2 27. 4 27. 6 27. 8 28. 2 28. 4 - 40 0 25 85 125 34.4 34.6 34.8 35.2 35.4 35.6 35. .8 - 40 0 25 85 125

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 7 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL CHARACTERISTICS (continued) Performance waveforms are tested on the evaluation board of the Design Example section. VIN=5V, VCC=5V, VOUT=1.2V, L=1.0µH, TA=+25°C, unless otherwise noted. VCC UVLO Threshold vs. Temperature 2.55 2.60 2.65 2.70 2.75 2.80 2.85 2.90 -50 -25 0 25 50 75 100 125 150 VCC Rising Threshold VCC Falling Threshold Soft-Start/Shutdown Current vs. Temperature EN Threshold vs. Temperature 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 -50 -25 0 25 50 75 100 125 150 6.90 6.95 7.00 7.05 7.10 7.15 7.20 7.25 7.30 7.35 7.40 -50 0 50 100 150 EN Rising Threshold EN Falling Threshold Reference Voltage vs. Temperature OVP Threshold vs. Temperature 606 607 608 609 610 611 612 613 614 615 -50 0 50 100 150 119.5 120.0 120.5 121.0 121.5 122.0 122.5 -50 -25 0 25 50 75 100 125 150 MPQ8612-12 MPQ8612-16 MPQ8612-20

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 8 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS (continued) Performance waveforms are tested on the evaluation board of the Design Example section. MPQ8612-12, VIN=5V, VCC=5V, VOUT=1.2V, L=1.0µH, TA=+25°C, unless otherwise noted. OUTPUT CURRENT (A)OUTPUT CURRENT (A) OUTPUT CURRENT (A) OUTPUT CURRENT (A) OUTPUT CURRENT (A) OUTPUT CURRENT (A)OUTPUT CURRENT (A) OUTPUT CURRENT (A) OUTPUT CURRENT (A) 100 0.01 0.1 1 10 100 VIN=6V VIN=5V VIN=4.2V VIN=3.3V 100 0.01 0.1 1 10 100 VIN=6V VIN=5V VIN=4.2V VIN=3.3V 100 0.01 0.1 1 10 100 VIN=3.3V VIN=4.2V VIN=5V VIN=6V 100 0.01 0.1 1 10 100 VIN=6V VIN=5V VIN=4.2V VIN=3.3V 100 0.01 0.1 1 10 100 VIN=4.2V VIN=5V VIN=6V 100 0.01 0.1 1 10 100 VIN=4.2V VIN=3.3V VIN=5V VIN=6V 100 0.01 0.1 1 10 100 VIN=5V VIN=6V VIN=4.2V VIN=3.3V 100 0.01 0.1 1 10 100 VIN=4.2V VIN=5V VIN=6V VIN=3.3V 100 0.01 0.1 1 10 100 VIN=4.2V VIN=5V VIN=6V VIN=3.3V

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 9 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS (continued) Performance waveforms are tested on the evaluation board of the Design Example section. MPQ8612-12, VIN=5V, VCC=5V, VOUT=1.2V, L=1.0µH, TA=+25°C, unless otherwise noted. 100 0.01 0.1 1 10 100 -1.00 -0.50 0.00 0.50 1.00 -0.6 -0.4 -0.2 0.2 0.4 0.6 0 2 4 6 8 10 123456 200 400 600 800 1000 1200 200 400 600 800 1000 1200 550 570 590 610 630 650 3 3.5 4 4.5 5 5.5 6 100 200 300 400 500 600 700 024 68 1 0 1 2

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 10 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS (continued) Performance waveforms are tested on the evaluation board of the Design Example section. MPQ8612GL-12, VIN=5V, VCC=5V, VOUT=1.2V, L=1.0µH, TA=+25°C, unless otherwise noted. VSW 200mV/div. VSW 1V/div. Dead Time (on) IOUT =12A Dead Time Off IOUT =12A VSW 5V/div. VIN AC Coupled 10mV/div. VOUT AC Coupled 20mV/div. IL 2.5A/div. VSW 5V/div. VIN AC Coupled 10mV/div. VOUT AC Coupled 10mV/div. IL 1A/div. VSW 5V/div. VIN AC Coupled 100mV/div. VOUT AC Coupled 10mV/div. IL 10A/div. VPG 1V/div. VIN 2V/div. VOUT 1V/div. VPG 2V/div. VIN 2V/div. VOUT 1V/div. VPG 5V/div. VEN 5V/div. VOUT 1V/div. VPG 5V/div. VEN 5V/div. VOUT 1V/div. Input/Output Voltage Rippl IOUT = 0A Input/Output Voltage Ripple IOUT = 0.4A Input/Output Voltage Ripple IOUT = 12A Power Good Through Vin Start-Up IOUT = 12A Power Good Through Vin Shutdown IOUT = 12A Power Good Through EN Start-Up IOUT = 12A Power Good Through EN Shutdown IOUT = 12A

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 11 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS (continued) Performance waveforms are tested on the evaluation board of the Design Example section. MPQ8612GL-12, VIN=5V, VCC=5V, VOUT=1.2V, L=1.0µH, TA=+25°C, unless otherwise noted. VOUT 1V/div. VIN 5V/div. VSW 5V/div. IL 1A/div. VOUT 1V/div. VIN 5V/div. VSW 5V/div. IL 10A/div. VOUT 1V/div. VEN 5V/div. VSW 5V/div. IL 2.5A/div. VOUT 1V/div. VEN 5V/div. VSW 5V/div. IL 1A/div. VOUT 1V/div. VEN 5V/div. VSW 5V/div. IL 10A/div. VOUT 1V/div. VIN 5V/div. VSW 5V/div. IL 10A/div. VOUT 1V/div. VIN 5V/div. VSW 2V/div. IL 1A/div. VOUT 1V/div. VIN 5V/div. VSW 5V/div. IL 10A/div. Start-Up Through Vin IOUT = 0A Start-Up Through Vin IOUT = 12A Shutdown Through Vin IOUT = 0A Shutdown Through Vin IOUT = 12A Start-Up Through EN IOUT = 0A Start-Up Through EN IOUT = 12A Shutdown Through EN IOUT = 0A Shutdown Through EN IOUT = 12A VOUT AC Coupled 200mV/div. IL 5A/div.

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 12 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS (continued) Performance waveforms are tested on the evaluation board of the Design Example section. MPQ8612GL-12, VIN=5V, VCC=5V, VOUT=1.2V, L=1.0µH, TA=+25°C, unless otherwise noted. VOUT 1V/div. VSW 5V/div. IL 10A/div. VOUT 1V/div. VSW 5V/div. IL 10A/div. VOUT 1V/div. VSW 5V/div. IL 10A/div. Short Circuit Protection Thermal Shutdown IOUT = 12A Thermal Recovery IOUT = 12A

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 13 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. PIN FUNCTIONS MPQ8612GL-12 PIN # Name Description 1 AGND Analog ground. 2 FB Feedback. An external resistor divider from the output to GND, tapped to the FB pin, sets the output voltage. It is recommended to place t he resistor divider as close to FB pin as possible. Vias should be avoided on the FB traces. 3 SS Soft Start. Connect on external capacitor to program the soft start time for the switch mode regulator. 4 EN Enable pin. Pull this pin higher than 1.25V to enable the chip. For automatic start-up, connect EN pin to VIN with 100KΩ resistor. Can be used to set the on/off threshold (adjust UVLO) with two additional resistors.

5 VCC

External bias supply voltage for driver and control circuits. For 1.5V to 3V input application, provide VCC with separate 3.3V /5V bias supply. For 3V to 6V input application, provide VCC with separate 3. 3V/5V bias or tie VCC to VIN with 10ohm resistor. Decouple with a minimum 4.7µF ceramic capacitor as close to the pin as possible. X7R or X5R grade dielectric ceramic capacitors are recommended for their stable temperature characteristics.

6 PG Power good output, and it is high if the output voltage is higher than 90% of the nominal

voltage. There is a delay from FB ≥ 90% to PGOOD goes high. 7 BST Bootstrap. A capacitor connected between SW and BS pins is required to form a floating supply across the high-side switch driver. 8-9 GND System Ground. This pin is the reference ground of the regulated output voltage. For this reason care must be taken in PCB layout. 10-11 IN Supply Voltage. The IN pin supplies power for internal MOSFET and regulator. The MPQ8612 operate from a +3V to +6V input rail. An input capacitor is needed to decouple the input rail. Use wide PCB traces and multiple vias to make the connection.

12 FREQ

Frequency set during CCM operation. A resi stor connected between FREQ and IN is required to set the switching frequency. The ON time is determined by the input voltage and the resistor connected to the FREQ pin. IN connect through a resistor is used for line feed-forward and makes the frequency basically constant during input voltage’s variation. Recommend a 10pF decoupling capacitor from FREQ to GND. 13-14 SW Switch Output. Connect this pin to the inductor and bootstrap capacitor. This pin is driven up to the VIN voltage by the high-side switch during the on-time of the PWM duty cycle. The inductor current drives the SW pin negative during the off-time. The on-resistance of the low-side switch and the internal Scho ttky diode fixes the negative voltage. Use wide PCB traces to make the connection.

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 14 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. PIN FUNCTIONS (continued) MPQ8612GR-16, MPQ8612GR-20 PIN # Name Description 1 AGND Analog ground. 2 FB Feedback. An external resistor divider from the output to GND, tapped to the FB pin, sets the output voltage. It is recommended to place t he resistor divider as close to FB pin as possible. Vias should be avoided on the FB traces. 3 SS Soft Start. Connect on external capacitor to program the soft start time for the switch mode regulator. 4 EN Enable pin. Pull this pin higher than 1.25V to enable the chip. For automatic start-up, connect EN pin to VIN with 100KΩ resistor. Can be used to set the on/off threshold (adjust UVLO) with two additional resistors. External bias supply voltage for driver and control circuits. For 1.5V to 3V input application, provide VCC with separate 3. 3V/5V bias supply. For 3V to 6V input application, provide VCC with separate 3. 3V/5V bias or tie VCC to VIN with 10ohm resistor. Decouple with a minimum 4.7µF ceramic capacitor as close to the pin as possible. X7R or X5R grade dielectric cera mic capacitors are recommended for their stable temperature characteristics. voltage. There is a delay from FB ≥ 90% to PGOOD goes high. 7 BST Bootstrap. A capacitor connected between SW and BS pins is required to form a floating supply across the high-side switch driver. 8-10 GND System Ground. This pin is the reference gr ound of the regulated output voltage. For this reason care must be taken in PCB layout. 11-13 IN Supply Voltage. The IN pin supplies power for internal MOSFET and regulator. The MPQ8612 operate from a +3V to +6V input rail. An input capacitor is needed to decouple the input rail. Use wide PCB traces and multiple vias to make the connection.

14 FREQ

Frequency set during CCM operation. A resistor connected between FREQ and IN is required to set the switching frequency. The ON time is determined by the input voltage and the resistor connected to the FREQ pin. IN connect through a resistor is used for line feed-forward and makes the frequency basically constant during input voltage’s variation. Recommend a 10pF decoupling capacitor from FREQ to GND. 15-17 SW Switch Output. Connect this pin to the inductor and bootstrap capacitor. This pin is driven up to the VIN voltage by the high-side switch during the on-time of the PWM duty cycle. The inductor current drives the SW pin negativ e during the off-time. The on-resistance of the low-side switch and the internal Schottky diode fixes the negative voltage. Use wide PCB traces to make the connection.

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 15 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. BLOCK DIAGRAM 0.6V 0.3V 0.75V FREQ VCC EN SS FB PG IN BST SW GND AGND RSEN HS-FETHS Driver LS-FETLS Driver Current Modulator LOGIC Current Sense Amplifer Refresh Timer OCOver-Current Timer xS xR Q PWM BSTREG OFF Timer ILIM HS Limit Comparator START ON TimerLoop Comparator UV OV UV Detect Comparator OV Detect Comparator PGOOD Comparator SOFT START/STOP REFERENCE 1MEG VCC VCC Figure 1—Functional Block Diagram

3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TSW is the switching period. for design steps with small ESR caps. Figure 7. The external ramp is derived from the slope1 should be design follow equation 9. Where Io is the load current.

12 O O U T

Where Ro is the equivalent load resistor.

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 19 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. larger. If one wants a system with less jitter during ultra light load condition, the values of the VFB resistors should not be too big, however, that will decrease the light load efficiency. Soft Start/Stop The MPQ8612 employs soft start/stop (SS) mechanism to ensure smooth output during power up and power down. When the EN pin becomes high, an internal current source (8μA) charges up the SS capacitor C6. The SS capacitor voltage takes over the REF voltage to the PWM comparator. The output voltage smoothly ramps up with the SS voltage. Once the SS voltage reaches the same level as the REF voltage, it keeps ramping up while V REF takes over the PWM comparator. At this point, the soft start finishes and it enters into steady state operation. When the EN pin is pulled to low, the SS CAP voltage is discharged through an 8uA internal current source. Once the SS voltage reaches REF voltage, it takes over the PWM comparator. The output voltage will decrease smoothly with SS voltage until zero level. The SS capacitor value can be determined as follows: SS SS SS REF t( m s ) I( A )C( n F ) V  (11) If the output capacitors have large capacitance value, it’s not recommended to set the SS time too small. Otherwise, it’s easy to hit the current limit during SS. A minimum value of 4.7nF should be used if the output capacitance value is larger than 330μF. Pre-Bias Startup If the output is pre-biased to a certain voltage during startup, the MPQ8612 will disable the switching of both high-side and low-side switches until the voltage on the internal soft-start capacitor exceeds the sensed output voltage at the FB pin. Power Good (PG) The MPQ8612 has power-good (PG) output. It can be connected to V CC or other voltage source through a resistor (e.g. 100k). When the MPQ8612 is powered on and FB voltage reaches above 90% of REF voltage, the PG pin is pulled high. When the FB voltage drops to 70% of REF voltage or the part is not powered on, the PG pin will be pulled low. Over-Current Protection (OCP) The MPQ8612 enters over-current protection mode when the inductor current hits the current limit, and tries to recover from over-current fault with hiccup mode. That means in over-current protection, the chip will disable output power stage, discharge soft-start capacitor and then automatically try to soft-start again. If the over- current condition still holds after soft-start ends, the chip repeats this operation cycle till over- current disappears and output rises back to regulation level. The MPQ8612 also operates in hiccup mode when short circuit happens. Over/Under –Voltage Protection (OVP/UVP) The MPQ8612 has non-latching over voltage protection. It monitors the output voltage through a resistor divider feedback (FB) voltage to detect over-voltage on the output. When the FB voltage is higher than 120% of the REF voltage (0.608V), the LS-FET will be turned on while the HS-FET will be off. The LS-FET keeps on until it hits the negative current limit and turns off for 100ns. If over voltage condition still holds, the chip repeats this operation cycle till the FB voltage drops below 110% of the REF voltage. When the FB voltage is below 50% of the REF voltage (0.608V), it is recognized as under- voltage (UV). Usually, UVP accompanies a hit in current limit and results in OCP. Configuring the EN Control The EN pin provides electrical on/off control of the device. Set EN high to turn on the regulator and low to turn it off. Do not float this pin. For automatic start-up, the EN pin can be pulled up to input voltage through a resistive voltage divider. Choose the values of the pull-up resistor UP from VIN pin to EN pin) and the pull-down resistor (R DOWN from EN pin to GND) to determine the automatic start-up voltage: UP DOWN IN START DOWN RRV1 . 4 R  (12)

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 22 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. should be not larger than 0.47uF considering start up performance. In case one wants to use larger Cdc for a better FB noise immunity,combined with reduced R1 and R2 to limit the Cdc in a reasonable value without affecting the system start up. Be noted that even when the Cdc is applied, the load and line regulation are still Vramp related. Ceramic SW FB VoL Cdc R4 C4 Figure 12—Simplified Circuit of Ceramic Capacitor with DC blocking capacitor Input Capacitor The input current to the step-down converter is discontinuous. Therefore, a capacitor is required to supply the AC current to the step-down converter while maintaining the DC input voltage. Ceramic capacitors are recommended for best performance. In the layout, it’s recommended to put the input capacitors as close to the IN pin as possible. The capacitance varies significantly over temperature. Capacitors with X5R and X7R ceramic dielectrics are recommended because they are fairly stable over temperature. The capacitors must also have a ripple current rating greater than the maximum input ripple current of the converter. The input ripple current can be estimated as follows: OUT OUT CIN OUT IN IN VVII ( 1 ) VV   (20) The worst-case condition occurs at V IN = 2V OUT, where: OUT CIN II 2 (21) For simplification, choose the input capacitor whose RMS current rating is greater than half of the maximum load current. The input capacitance value determines the input voltage ripple of the converter. If there is input voltage ripple requirement in the system design, choose the input capacitor that meets the specification The input voltage ripple can be estimated as follows: OUT OUT OUT IN SW IN IN IN (22) The worst-case condition occurs at VIN = 2VOUT, where: OUT IN SW IN I1V 4f C   (23) Output Capacitor The output capacitor is required to maintain the DC output voltage. Ceramic or POSCAP capacitors are recommended. The output voltage ripple can be estimated as: OUT OUT OUT ESR SW IN SW OUT (24) In the case of ceramic capacitors, the impedance at the switching frequency is dominated by the capacitance. The output voltage ripple is mainly caused by the capacitance. For simplification, the output voltage ripple can be estimated as: OUT OUT OUT 2 INSW OUT (25) The output voltage ripple caused by ESR is very small. Therefore, an external ramp is needed to stabilize the system. The external ramp can be generated through resistor R4 and capacitor C4 following equation 5, 8 and 9. In the case of POSCAP capacitors, the ESR dominates the impedance at the switching frequency. The ramp voltage generated from the ESR is high enough to stabilize the system. Therefore, an external ramp is not needed. A minimum ESR value around 12m Ω is required to ensure stable operation of the converter. For simplification, the output ripple can be approximated as: OUT OUT OUT ESR SW IN (26) Inductor The inductor is required to supply constant current to the output load while being driven by the switching input voltage. A larger value

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 23 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. inductor will result in less ripple current and lower output ripple voltage. However, a larger value inductor will have a larger physical size, higher series resistance, and/or lower saturation current. A good rule for determining the inductor value is to allow the peak-to-peak ripple current in the inductor to be approximately 10~30% of the maximum output current. Also, make sure that the peak inductor current is below the current limit of the device. The inductance value can be calculated as: OUT OUT SW L IN (27) Where ΔIL is the peak-to-peak inductor ripple current. Choose an inductor that will not saturate under the maximum inductor peak current. The peak inductor current can be calculated as: OUT OUT LP OUT SW IN (28) The inductors listed in Table 1 are highly recommended for the high efficiency they can provide. Table 1—Inductor Selection Guide Part Number Manufacturer Inductance (µH) DCR (mΩ) Current Rating (A) Dimensions L x W x H (mm3) Switching Frequency (kHz) Typical Design Parameter Tables The following tables include recommended component values for typical output voltages (1.0V, 1.2V, 1.8V, 3.3V) and switching frequencies (600kHz, 800kHz, and 1MHz). Refer to Tables 2-4 for design cases without external ramp compensation and Tables 5-7 for design cases with external ramp compensation. External ramp is not needed when high-ESR capacitors, such as electrolytic or POSCAPs are used. External ramp is needed when low-ESR capacitors, such as ceramic capacitors are used. For cases not listed in this datasheet, a calculator in excel spreadsheet can also be requested through a local sales representative to assist with the calculation. Table 2—C OUT-Poscap, 600kHz, 5VIN VOUT (V) L (μH) (kΩ) (kΩ) (kΩ) 1.0 1.0 19.8 30 300 1.2 1.0 29.4 30 365 1.5 1.0 29.4 20 453 1.8 1.0 39.2 20 549 3.3 1.0 44.2 10 1000 Table 3—C OUT-Poscap, 800kHz, 5VIN VOUT (V) L (μH) (kΩ) (kΩ) (kΩ) 1.0 0.75 20 30 210 1.2 0.75 20 20 270 1.5 0.75 30 20 330 1.8 0.75 39 20 499 3.3 0.75 44.2 10 750 Table 5—C OUT-Ceramic, 600kHz, 5VIN VOUT (V) L (μH) (kΩ) (kΩ) (kΩ) (pF) (kΩ) 1.0 1.0 21 30 240 470 309 1.2 1.0 33 30 220 470 365 1.5 1.0 51 30 330 390 464 1.8 1.0 45 20 270 470 549 3.3 1.0 62 10 160 680 953 Table 6—C OUT-Ceramic, 800kHz, 5VIN VOUT (V) L (μH) (kΩ) (kΩ) (kΩ) (pF) (kΩ) 1.0 0.75 21 30 200 470 226 1.2 0.75 34 30 200 470 270 1.5 0.75 34 20 220 470 324 1.8 0.75 47.5 20 225 470 402 3.3 0.75 57.6 10 200 560 750

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER MPQ8612 Rev. 1.21 www.MonolithicPower.com 26 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved.

PACKAGE INFORMATION

QFN (3mmx4mm) SIDE VIEW BOTTOM VIEW NOTE: 1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH . 3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETERS MAX. 4) JEDEC REFERENCE IS MO -220. 5) DRAWING IS NOT TO SCALE. PIN 1 ID MARKING TOP VIEW PIN 1 ID INDEX AREA RECOMMENDED LAND PATTERN 0.1x45

MPQ8612 ― 12A/16A/20A, 6V, SYNCHRONOUS STEP-DOWN CONVERTER NOTICE: The information in this document is subject to change wi thout notice. Please contact M PS for current specifications. Users should warrant and guarantee that third party Intellectual Property rights ar e not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MPQ8612 Rev. 1.21 www.MonolithicPower.com 27 3/9/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. QFN (4mmx4mm)

Summary

High Efficiency, 12A/16A/20A, 6V Synchronous Step-down Converter

Description