MPM38222 Dual 2A, 2.7V-6V, Power Module, Synchronous, Step-Down Converter with Integrated Inductors DESCRIPTION FEATURES The MPM38222 is a dual-channel DC/DC module. The module includes a monolithic, step-down, switch-mode converter with built-in, internal power MOSFETs and inductors. The MPM38222 is designed to simplify power system design and provide ease of use. The MPM38222 operates from a 2.7V to 6V input, generates an output voltage as low as 0.608V, and has a 45µA quiescent current, making it ideal for powering portable equipment that run on a single-cell Lithium-ion (Li+) battery. The MPM38222 integrates dual, 80mΩ, high-side switches and 35mΩ synchronous rectifiers for high efficiency without an external Schottky diode. Peak-current-mode control and internal compensation limit the minimum number of readily available external components. Full protection features include cycle-by-cycle current limiting and thermal shutdown. The MPM38222 is available in a small, surfacemounted, QFN-14 (4mmx4mmx1.6mm) package. Dual 2A Output Current >93% Peak Efficiency >80% Light-Load Efficiency Ultra-Low IQ: 45μA 80mΩ and 35mΩ Internal Power MOSFET Wide 2.7V to 6V Operating Input Range Default 1MHz Switching Frequency 180° Phase-Shifted Operation 100% Duty Cycle Operation Cycle-by-Cycle Over-Current Protection (OCP) Short-Circuit Protection (SCP) with Hiccup Mode Thermal Shutdown Available in a Small QFN-14 (4mmx4mmx1.6mm) Package APPLICATIONS Optical Modules Industrial Products IoT Devices LDO Replacements Medical Devices All MPS parts are lead-free, halogen-free, and adhere to the RoHS directive. For MPS green status, please visit the MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 1 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS ORDERING INFORMATION Part Number* Package Top Marking MPM38222GR QFN-14 (4mmx4mmx1.6mm) See Below * For Tape & Reel, add suffix –Z (e.g. MPM38222GR–Z) TOP MARKING MPS: MPS prefix Y: Year code WW: Week code M38222: Product code of MPM38222GR LLLLLL: Lot number M: Module PACKAGE REFERENCE TOP VIEW GND VIN 14 13 GND 1 12 FB1 GND 2 11 FB2 EN1 3 10 EN2 SW1 4 9 SW2 OUT1 5 8 OUT2 6 7 OUT1 OUT2 QFN-14 (4mmx4mmx1.6mm) MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 2 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance (4) Supply voltage (VIN) ...................................6.5V VSW ............................... -0.3V (-5V for <10ns) to 6.5V (9V for <10ns) All other pins ............................... -0.3V to +6.5V Junction temperature ............................... 150°C Lead temperature .................................... 260°C Continuous power dissipation (TA = +25°C) (2) ..................................................................2.8W QFN-14 (4mmx4mmx1.6mm) ... 44 ..... 9 .... °C/W Recommended Operating Conditions (3) Supply voltage (VIN) ......................... 2.7V to 6V Output voltage (VOUT) ................... 0.608V to VIN Operating junction temp. (TJ). .. -40°C to +125°C 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 produces an excessive die temperature, causing the regulator to 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 JEDEC51-7, 4 layer PCB. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 3 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS ELECTRICAL CHARACTERISTICS VIN = EN = 3.6V, TJ = -40°C to +125°C(5), typical value is tested at TJ = +25°C. The limit over temperature is guaranteed by characterization, unless otherwise noted. Parameters Feedback voltage Feedback bias current Symbol Condition VFB IBIAS(FB) 2.7V VIN 6V Min Typ Max TJ = 25°C -2% 0.608 2% TJ = -40°C to 125°C -3% VFB = 0.63V 3% ±10 50 Units V/% nA P-FET switch on resistance RDS(ON)_P VIN = 5V 80 mΩ N-FET switch on resistance RDS(ON)_N VIN = 5V 35 mΩ LDCR 45 mΩ L 1 μH Inductor DC resistance Inductor inductance(7) Inductor rated DC current(7) ISAT ∆L/L = 30% 3.3 A IR ∆T = 40°C 2.7 A Switch leakage current P-FET peak current limit Switching frequency ILIMIT_HS fSW VEN = 0V, VIN = 6V, VSW = 0V and 6V, TJ = 25°C -1 0 1 μA Sourcing, D = 40% 2.7 3.5 4.5 A -20% 1000 +20% kHz/% TJ = -40°C to +125°C(5) Max duty cycle 100 % Minimum off time TMIN_OFF 100 ns Minimum on time(6) TMIN_ON 90 ns Internal soft-start time TSS_ON 0.5 ms IN under-voltage lockout threshold IN under-voltage lockout threshold hysteresis Rising edge 2.5 2.65 300 EN input logic high voltage -40°C TJ +125°C EN input logic low voltage -40°C TJ +125°C Supply current (shutdown) ISD VEN = 0V, TJ = 25°C Supply current (quiescent) IQ VIN = 3.6V, VEN = 2V, VFB = 0.65V, TJ = -25°C Thermal shutdown threshold(6) 2.4 Hysteresis = 30°C Phase shift mV 1.2 35 V V 0.4 V 0 1 μA 45 55 μA 160 °C 180 degree NOTES: 5) Not tested in production, guaranteed by over-temperature correlation. 6) Guaranteed by engineering sample characterization. 7) Not tested in production, guaranteed by the inductor’s datasheet. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 4 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS TYPICAL PERFORMANCE CHARACTERISTICS VIN = 5V, VOUT1 = 1.8V, VOUT2 = 1.2V, COUT1 = COUT2 = 22µF, TA = 25°C, unless otherwise noted. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 5 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V, VOUT1 = 1.8V, VOUT2 = 1.2V, COUT1 = COUT2 = 22µF, TA = 25°C, unless otherwise noted. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 6 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V, VOUT1 = 1.8V, VOUT2 = 1.2V, L = 1µH, COUT1 = COUT2 = 22µF, TA = 25°C, unless otherwise noted. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 7 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V, VOUT1 = 1.8V, VOUT2 = 1.2V, L = 1µH, COUT1 = COUT2 = 22µF, TA = 25°C, unless otherwise noted. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 8 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V, VOUT1 = 1.8V, VOUT2 = 1.2V, L = 1µH, COUT1 = COUT2 = 22µF, TA = 25°C, unless otherwise noted. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 9 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V, VOUT1 = 1.8V, VOUT2 = 1.2V, L = 1µH, COUT1 = COUT2 = 22µF, TA = 25°C, unless otherwise noted. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 10 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS PIN FUNCTIONS Pin # Name Description 1, 2, 14 3 GND EN1 4 SW1 5, 6 7, 8 OUT1 OUT2 9 SW2 10 EN2 11 FB2 12 FB1 13 VIN Power ground. Channel 1 enable. Switch node. SW1 connects to the channel 1 internal high-side and low-side power MOSFETs. SW1 also connects to the inductor. Channel 1 power output. Channel 2 power output. Switch node. SW2 connects to the channel 2 internal high-side and low-side power MOSFETs. SW2 also connects to the inductor. Channel 2 enable. Feedback 2. FB2 is the error amplifier input. Connect FB2 to the tap of an external resistor divider between the output and GND. FB2 sets the regulation voltage. Feedback 1. FB1 is the error amplifier input. Connect FB1 to the tap of an external resistor divider between the output and GND. FB1 sets the regulation voltage. Input supply. VIN requires a decoupling capacitor to ground to reduce switching spikes. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 11 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS BLOCK DIAGRAM UVLO VIN UVLO & Bandgap MAIN SWITCH PCH 0.608V INTERNAL SS FB1 CONTROL LOGIC COMP1 0.608V PWM VOUT1 Hi-Z SW1 ISLOPE1 EN1 PH1 Slope Comp SYNCHRONOUS RECTIFIER NCH OSC1 1MHz OSCILLAT OR LOW SIDE GATE DRIVER GND PH2 EN2 OSC2 Slope Comp MAIN SWITCH PCH ISLOPE2 INTERNAL SS FB2 0.608V COMP2 PWM CONTROL LOGIC VOUT2 Hi-Z SW2 SYNCHRONOUS RECTIFIER NCH LOW SIDE GATE DRIVER GND Figure 1: Functional Block Diagram MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 12 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS OPERATION Table 1: Modes of Operation The MPM38222 is a dual-channel DC/DC module that includes a monolithic, step-down, switch-mode converter with built-in, internal power MOSFETs and inductors. Both channels have peak-current mode with internal compensation for faster transient response and cycle-by-cycle current limit. Condition The MPM38222 is optimized for low-voltage, space-constrained applications where efficiency and small size are critical. 180° Phase Shift By default, the MPM38222’s two channels operate at a 180° phase shift to reduce input current ripple (see Table 1). The smaller current ripple allows for use of a smaller input bypass capacitor. In continuous conduction mode (CCM), two internal clocks control the switching. The high-side MOSFET (HS-FET) turns on at the corresponding clock’s rising edge. CLK1 CLk1, 2 has a 180o phase shift CLK2 SW1 SW2 t Figure 2: Clock/Switching Timing The switching frequency drops below 1MHz with a fixed off time when operating at a low dropout voltage. Once the input voltage recovers to a high value, switching for PWM mode resumes normally and synchronizes with the master oscillator for phase-shifted operation. Light-Load Operation In light loads, the MPM38222 uses a proprietary control scheme to save power and improve efficiency (see Table 1). The MPM38222 turns off the low-side switch when the inductor current starts to reverse, and then works in discontinuous conduction mode (DCM) operation. When either channel enters DCM or low-dropout operation, it will not be controlled by the internal 1MHz oscillator. CH1 CH2 1 Heavy load 2 Light load 3 Low dropout 4 5 6 7 8 9 Heavy load Light load Heavy load Low dropout Light load Low dropout Light load Heavy load Low dropout Heavy load Low dropout Light load Mode CH1 1MHz CCM DCM Fixed off time 0.95MHz CCM DCM 0.95MHz CCM Fixed off time DCM Fixed off time CH2 1MHz CCM,180° phase DCM Fixed off time DCM 0.95MHz CCM Fixed off time 0.95MHz CCM Fixed off time DCM DCM occurs only after the low-side switch is turned off by the ZCD circuit. Considering the ZCD circuit propagation time, the typical delay is 50ns. This means that the inductor current continues falling after ZCD is triggered during this delay. If the inductor current falling slew rate is fast (VOUT is high or close to VIN), the low-side MOSFET (LS-FET) is turned off at the moment the inductor current is negative. This prevents the MPM38222 from entering DCM operation. If DCM operation is required, the off time of the LS-FET in CCM should be longer than 100ns. For example, if VIN is 3.4V, and VOUT is 3.3V, then the off time in CCM is about 30ns. It is difficult to enter DCM at light load. Soft Start (SS) The MPM38222 has a built-in soft start (SS) that ramps up the output voltage at a controlled slew rate to avoid overshooting at start-up. The soft-start time is about 0.5ms. Over-Current Protection (OCP) and Hiccup The MPM38222 has a cycle-by-cycle overcurrent limit when the inductor current peak value exceeds the set current-limit threshold. The output voltage drops until VFB is below the under-voltage (UV) threshold, typically 75% below the reference. Once UV is triggered, the MPM38222 enters hiccup mode to restart the MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 13 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS part periodically. This protection mode is especially useful when the output is deadshorted to ground, and reduces the average short-circuit current greatly to alleviate thermal issues and protect the regulator. The curve is based on MPS’s standard evaluation board (EVB). The junction-toambient thermal resistance (θJA) of the MPS EVB is 47°C/W. The thermal resistance may differ with different layouts. De-Rating Current Operation Figure 3 provides guidelines for the maximum allowed power loss on the IC at a certain ambient temperature. It describes the maximum allowed IC power loss when the junction temperature reaches 125°C. For example, the application condition is VIN = 5V, VOUT1 = 1.2V/2A, VOUT2 = 1.8V/2A. From the efficiency curve, if the single-channel efficiency is about 81% at 1.2V/2A and 86% at 1.8V/2A, then the total power loss is about 1.15W. Figure 3 also shows that the maximum allowable power loss is 2.1W at a 25°C ambient temperature. Since the IC power loss is less than 2.1W, the application is safe when the two channels take a 2A load at TA = 25°C. If the IC power loss is higher than the maximum allowable value, the junction temperature is over 125°C. It is recommended to de-rate the load current or lower the ambient temperature. Figure 3: De-Rating Power Loss MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 14 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS APPLICATION INFORMATION Output Voltage External resistor dividers connected to the FB pins set the output voltage. The feedback resistor connected to FB1 (R1) also sets the feedback loop bandwidth (fC). fC does not exceed 0.1xfSW. When using a ceramic output capacitor (CO), set the range to 50kHz and 100kHz for optimal transient performance and good phase margin. When using an electrolytic capacitor, set the loop bandwidth no higher than a quarter of the ESR zero frequency (fESR). fESR can be calculated with Equation (1): fESR 1 (1) 2π RESR CO Choose R1 by referring to Table 2. R2 can then be calculated with Equation (2): R2 R1 VOUT 1 0.608V (2) Table 2: Resistor Values vs. Output Voltage VOUT R1 R2 1.2V 1.5V 200kΩ 200kΩ 200kΩ 133kΩ COUT (Ceramic) 22μF 22μF 1.8V 2.5V 3.3V 200kΩ 150kΩ 120kΩ 100kΩ 47.5kΩ 26.7kΩ 22μF 22μF 22μF Selecting the Input Capacitor The input current to the step-down converter is discontinuous and therefore requires a capacitor to supply AC current to the step-down converter while maintaining the DC input voltage. Use low ESR capacitors for the best performance. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. For most applications, a 22μF capacitor is sufficient. Since the input capacitor absorbs the input switching current, it requires an adequate ripple current rating. The RMS current in the input capacitor can be estimated with Equation (3): IC1 ILOAD x VOUT V x(1 OUT ) VIN VIN (3) The worst-case condition occurs at VIN = 2VOUT, shown in Equation (4): IC1 ILOAD 2 (4) The input capacitor can be electrolytic, tantalum, or ceramic. When using electrolytic or tantalum capacitors, add a small, high-quality, ceramic capacitor (e.g.: 0.1μF) as close to the IC as possible. When using ceramic capacitors, ensure that they have enough capacitance to provide a sufficient charge to prevent excessive voltage ripple at the input. The input voltage ripple caused by capacitance can be estimated with Equation (5): ∆VIN= ILOAD VOUT VOUT × ×(1) FS × C1 VIN VIN (5) Output Capacitor The output capacitor limits the output voltage ripple and ensures a stable regulation loop. Select an output capacitor with a low impedance at the switching frequency. Use ceramic capacitors with X5R or X7R dielectrics. Using an electrolytic capacitor may result in additional output voltage ripple and thermal issues, and requires additional care when selecting the feedback resistor (R1) due to the large ESR. The output ripple (∆VOUT) can be approximated with Equation (6): ΔVOUT (6) VOUT (VIN VOUT ) 1 ESR VIN fOSC L 8 fOSC CO MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 15 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS PCB Layout Guidelines Efficient PCB layout of the switching power supplies is critical for stable operation. A poor layout design can result in poor line or load regulation and stability issues. For best results, refer to Figure 4 and follow the guidelines below. 1. Place the high-current paths (GND, VIN) very close to the device with short, direct, and wide traces. 2. Place the input capacitor as close to VIN and GND as possible. 3. Place the external feedback resistors next to FB. Design Example Table 3 is a design example following the application guidelines for the specifications below. Table 3: Design Example VIN 5V VOUT1 1.8V VOUT2 1.2V The detailed application schematic is shown in Figure 5. The typical performance and circuit waveforms are shown in the Typical Performance Characteristics section. For more device applications, please refer to the related evaluation board datasheets. Top Layer GND R5 EN1 R6 EN2 Bottom Layer Figure 4: Recommended Layout MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 16 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS TYPICAL APPLICATION CIRCUIT VIN 5V C1 22μF R5 100kΩ R6 100kΩ EN1 VIN EN2 VOUT1 1.8V C2 22μF EN2 EN1 VOUT2 1.2V VOUT1 VOUT2 MPM38222 R1 200kΩ R3 200kΩ C3 22μF FB1 GND FB2 R2 100kΩ R4 200kΩ Figure 5: Typical Application Circuit MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 17 MPM38222 – 6V, 2A, DUAL-CHANNEL MODULE WITH INTEGRATED INDUCTORS PACKAGE OUTLINE DRAWING FOR 14L FCMQFN (4X4mm) PACKAGE INFORMATIONMF-PO-D-0246 revision 0.0 QFN-14 (4mmx4mmx1.6mm) PIN 1 ID MARKING PIN 1 ID INDEX AREA BOTTOM VIEW TOP VIEW SIDE 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. RECOMMENDED LAND PATTERN NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications. 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. MPM38222 Rev. 1.0 www.MonolithicPower.com 8/4/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 18