MPQ4462DN-AEC1-LF

MPQ4462-AEC1 3.5A, 4MHz, 36V, Step-Down Converter AEC-Q100 Qualified DESCRIPTION FEATURES The MPQ4462 is a high-frequency, step-down, switching regulator with an integrated, high-side, high-voltage, power MOSFET. It provides a 3.5A output with current-mode control for fast loop response and easy compensation.     The wide 3.8V-to-36V input range accommodates a variety of step-down applications, including those in an automotive input environment. A 120µA operational quiescent current allows for battery-powered applications.    Switching-frequency scaling allows for high power-conversion efficiency over a wide load range by scaling down the switching frequency at light loads to reduce the switching and gate driving losses. The frequency foldback prevent inductor-current runaway during startup, and thermal shutdown provides reliable and fault tolerant operation. The MPQ4462 can operate at up to 4MHz for EMI-sensitive applications, such as AM radio and ADSL applications. The MPQ4462 is available in both 3mm×3mm QFN10 and SOIC8E packages.    120μA Quiescent Current Wide 3.8V-to-36V Input Range 150mΩ Internal Power MOSFET Up to 4MHz Programmable Switching Frequency Stable with a Ceramic Capacitor Internal Soft-Start Internally-Set Current Limit without a Current Sensing Resistor Output Adjustable from 0.8V to 30V Available in 3mm×3mm QFN10 and SOIC8E Packages. Available in AEC-Q100 Qualified Grade 1 APPLICATIONS      High-Voltage Power Conversion Automotive Systems Industrial Power Systems Distributed Power Systems Battery Powered 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 MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 1 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED ORDERING INFORMATION Part Number Package Top Marking MPQ4462DQ* QFN10 (3mm×3mm) Z2 MPQ4462DN** SOIC8E MP4462DN MPQ4462DQ-AEC1* QFN10 (3mm×3mm) Z2 MPQ4462DN-AEC1** SOIC8E MP4462DN *For Tape & Reel, add suffix –Z (e.g. MPQ4462DQ–AEC1-Z); For RoHS, compliant packaging, add suffix –LF (e.g. MPQ4462DQ–AEC1-LF–Z). **For Tape & Reel, add suffix –Z (e.g. MPQ4462DN–AEC1-Z); For RoHS, compliant packaging, add suffix –LF (e.g. MPQ4462DN–AEC1-LF–Z). PACKAGE REFERENCE QFN10 SOIC8E ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance Supply Voltage (VIN).................... –0.3V to +40V Switch Voltage (VSW)............ –0.3V to VIN + 0.3V BST to SW .................................... –0.3V to +6V All Other Pins ................................ –0.3V to +6V (2) Continuous Power Dissipation (TA = +25°C) QFN10 (3mmx3mm) ..................................2.5W SOIC8E .....................................................2.5W Junction Temperature .............................. 150°C Lead Temperature ................................... 260°C Storage Temperature .............. –65°C to +150°C QFN10 (3mm×3mm) .............. 50 ...... 12 ... °C/W SOIC8E .................................. 50 ...... 10 ... °C/W Recommended Operating Conditions (3) Supply Voltage VIN .......................... 3.8V to 36V Output Voltage VOUT........................ 0.8V to 30V Operating Junct. 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. MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 2 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED ELECTRICAL CHARACTERISTICS VIN = 12V, VEN = 2.5V, VCOMP = 1.4V, TJ = −40°C to +125°C, unless otherwise noted. Typical values are at TJ = 25°C. Parameter Symbol Condition Feedback Voltage VFB (5) Min Typ Max VIN = 4.5V to 36V, TJ = 25°C 0.786 0.792 0.803 VIN = 4.5V to 36V 0.773 0.812 VBST – VSW = 5V 150 Upper Switch Leakage VEN = 0V, VSW = 0V, VIN = 36V 0.01 Current Limit Duty Cycle = 50% Upper Switch On Resistance COMP to Current Sense (5) Transconductance Error Amp Voltage Gain RDS(ON) 4.0 GCS (6) V mΩ 1 μA 5.5 A 9 A/V 200 V/V Error Amp Transconductance ICOMP = ±3µA Error Amp Min Source Current VFB = 0.7V 5 µA Error Amp Min Sink Current VFB = 0.9V –5 µA VIN UVLO Threshold 35 Units 2.6 VIN UVLO Hysteresis Soft-Start Time (5) VFB = 0V to 0.8V Oscillator Frequency RFREQ = 45.3kΩ Shutdown Supply Current Quiescent Supply Current Thermal Shutdown Minimum OFF Time 3.0 95 3.4 µA/V V 400 mV 1.5 ms 2 2.4 MHz VEN = 0V 11 18 µA No load, VFB = 0.9V 120 160 µA (5) Thermal Shutdown Hysteresis Minimum ON Time 1.6 60 (5) (5) (5) 150 °C 15 °C 100 ns 80 ns EN Rising Threshold 1.4 1.5 1.7 V EN Falling Threshold 1.1 1.2 1.4 V EN Threshold Hysteresis 300 mV Note: 5) Derived from bench characterization. Not tested in production. 6) Guaranteed by design. Not tested in production. MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 3 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED PIN FUNCTIONS QFN Pin # SOIC8E Pin # Name 1, 2 1 SW 3 2 EN 4 3 COMP 5 4 FB 6 5 GND 7 6 FREQ 8, 9 7 VIN 10 8 BST Description Switch Node. Output of the high-side switch. Requires a low-forward-drop Schottky diode to ground. Place the diode close to the SW pins to reduce switching spikes. Enable. Pull below the specified threshold to shut the chip down. Pull it up above the specified threshold or leave it floating to enable the chip. Compensation. Output of the error amplifier. Includes control-loop frequency compensation. Feedback. Input to the error amplifier. The tap of a resistor divider between the output and GND sets the output voltage to the internal +0.8V reference. Ground. Switching Frequency Set. Connect a resistor from this pin to ground to set the switching frequency. Input Supply. Supplies power to all internal control circuitry. Requires a decoupling capacitor to ground to minimize switching spikes. Bootstrap. Positive power supply to the internal, floating, high-side MOSFET driver. Connect a bypass capacitor between this pin and SW. Exposed Ground Pad. Connect to GND plane for optimal thermal performance. Pad MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 4 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED TYPICAL CHARACTERISTICS MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 5 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED TYPICAL CHARACTERISTICS (continued) MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 6 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED TYPICAL PERFORMANCE CHARACTERISTICS VIN = 12V, VOUT = 3.3V, C1 = 10µF, C2 = 22µF, L = 10µH and TA = +25°C, unless otherwise noted. MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 7 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 12V, VOUT = 3.3V, C1 = 10µF, C2 = 22µF, L = 10µH and TA = +25°C, unless otherwise noted. MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 8 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED BLOCK DIAGRAM Figure 1: Functional Block Diagram MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 9 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED OPERATION The MPQ4462 is a variable-frequency, asynchronous, step-down switching regulator with an integrated, high-side, high-voltage, power MOSFET. It provides a highly efficient output with current mode control for fast loop response and easy compensation. It features a wide input-voltage range, internal soft-start control, and precise current limiting. Its very-low operational quiescent current makes it suitable for battery-powered applications. disable the chip. Its falling threshold is precisely 1.2V, and its rising threshold is 1.5V (300mV higher). When floating, EN is pulled up to about 3.0V by an internal 1µA current source to remain enabled. To pull-down requires a 1µA current. When VEN is pulled down below 1.2V, the chip enters its lowest shutdown current mode. When VEN exceeds 0V but remains below its rising threshold, the chip remains in shutdown mode but the shutdown current increases slightly. PWM Control At moderate-to-high output current, the MPQ4462 operates in a fixed-frequency, peakcurrent-control mode to regulate the output voltage. The internal clock initiates a PWM cycle that turns the power MOSFET on. This MOSFET remains on until its current reaches the value set by VCOMP. When the power MOSFET is off, it remains off for at least 100ns before the next cycle starts. If the current in the power MOSFET does not reach the COMP set current value within one PWM period, the power MOSFET remains on to save a turn-off operation. Under-Voltage Lockout (UVLO) Under-voltage lockout (UVLO) protects the chip from operating at insufficient supply voltages. The UVLO rising threshold is about 3.0V while its falling threshold is a consistent 2.6V. Error Amplifier The error amplifier compares VFB to the internal reference (VREF) and outputs a current proportional to the difference between the two. This output current charges the external compensation network to form VCOMP, which controls the power MOSFET current. Thermal Shutdown Thermal shutdown prevents the chip from operating at exceedingly high temperatures. When the die temperature exceeds its upper threshold, the chip shuts down. When the temperature falls below its lower threshold, chip function resumes. While operating, the VCOMP minimum is clamped to 0.9V and its maximum is clamped to 2.0V. COMP is internally pulled down to GND in shutdown mode. COMP should not be pulled up beyond 2.6V. Floating Driver and Bootstrap Charging An external bootstrap capacitor powers the floating power MOSFET driver. This floating driver has its own UVLO protection, with a UVLO rising threshold of 2.2V with a falling threshold of 150mV. Internal Regulator The 2.6V internal regulator powers most of the internal circuits. This regulator takes VIN and operates in the full VIN range. When VIN exceeds 3.0V, the output of the regulator is in full regulation. When VIN falls below 3.0V, the output decreases. Enable Control The MPQ4462 has a dedicated enable-control pin (EN). Enable uses logic-high to enable and Internal Soft-Start The soft-start prevents the converter output voltage from overshooting during startup. When the chip starts, the internal circuitry generates a soft-start voltage (VSS) that ramps up from 0V to 2.6V. When VSSVREF, VREF resumes as the reference. A dedicated, internal, bootstrap regulator charges and regulates the bootstrap capacitor ~5V. When the voltage between the BST and SW nodes falls below its regulation voltage, a PMOS pass transistor connected from VIN to BST turns on. The current-charging path is VIN → BST → SW. The external circuit should provide enough voltage headroom to facilitate charging. MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 10 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED If VIN is sufficiently higher than VSW, the bootstrap capacitor charges. When the power MOSFET is ON, VIN≈VSW so the bootstrap capacitor cannot charge. When the external diode is ON, the VIN−VSW is at its maximum for optimal charging. When there is no current in the inductor, VSW=VOUT so VIN−VOUT charges the bootstrap capacitor. triggering any faults. VCOMP and the internal supply rail are then pulled down. Programmable Oscillator An external resistor (RFREQ) from the FREQ pin to ground sets the MPQ4462 oscillating frequency. At higher duty cycles, the bootstrap-charging period is shorter so the bootstrap capacitor may not charge sufficiently. If the internal circuit does not have sufficient voltage and the bootstrap capacitor is not charged, an external circuit can ensure the bootstrap voltage is in the normal operational region. The floating driver’s DC quiescent current ~20µA. Select a bleeding current at the SW node meets the following criterion: IO  VO  20A (R1  R2) Current Comparator and Current Limit A current-sense MOSFET accurately senses the power-MOSFET current. The sense value is compared to VCOMP by a high-speed current comparator. When the power MOSFET turns on, the comparator is first blanked till the end of the turn-on transition. When the sensed current exceeds VCOMP, the comparator output is low, turning off the power MOSFET. The cycle-bycycle maximum current of the internal power MOSFET is internally limited. Startup and Shutdown If both VIN and VEN exceed their respective thresholds, the chip starts. The reference block starts first, generating stable reference voltage and currents, and then the internal regulator is enabled. The regulator provides a stable supply for the remaining circuits. While the internal supply rail is up, an internal timer holds the power MOSFET OFF for about 50µs to blank the startup noise. When the internal soft-start block is enabled, it first holds VSS low before slowly ramping up. Three events can shut down the chip: VEN LOW, VIN LOW, and thermal shutdown. For shutdown, the power MOSFET turn off to avoid MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 11 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED APPLICATION INFORMATION `COMPONENT SELECTION Frequency The MPQ4462 has an externally-adjustable frequency using RFREQ. See Table1 for a list of recommended RFREQ value for various fS. Table 1: fS vs. RFREQ The inductor supplies constant current to the output load while being driven by the switching input voltage. A larger inductor will reduce ripple current and lower output ripple voltage, but is physically larger, and have a higher series resistance and/or lower saturation current. To choose a balanced inductor value, allow the peak-to-peak inductor ripple current approximately equal 30% of the maximum switching current limit. To ensure that the peak inductor current is below the maximum switch current limit estimate and inductor value as: RFREQ (kΩ) fS (MHz) 18 4 20 3.8 22.1 3.5 24 3.3 26.7 3 30 2.8 33.2 2.5 39 2.2 45.3 2 51 1.8 57.6 1.6 68 1.4 80.6 1.2 100 1 133 0.8 Output Rectifier Diode 200 0.5 340 0.3 536 0.2 The output rectifier diode supplies the current to the inductor when the high-side switch is off. To reduce losses due to the diode forward voltage and recovery times, use a Schottky diode. Output Voltage Connecting FB to the tap of a resistor divider from VOUT to ground sets VOUT such that: VOUT  VFB (R1  R2) R2 Without a load, the MPQ4462 outputs ~20µA from its high-side BST circuitry. Keep R2 ≤40kΩ to absorb this small amount of current. Selecting R2=40.2kΩ, R1 is then: R1  50.25  (VOUT  0.8)(k) For example, for VOUT=3.3V and R2=40.2kΩ, then R1 is 127kΩ. L1  VOUT fS  ΔIL  V    1  OUT  VIN   Where VOUT is the output voltage, VIN is the input voltage, fS is the switching frequency, and ΔIL is the peak-to-peak inductor-ripple current. Choose an inductor that will not saturate under the maximum inductor peak current, which is: ILP  ILOAD   V  VOUT   1  OUT  2  fS  L1  VIN  Where ILOAD is the load current. Choose a diode whose maximum reverse voltage rating exceeds the maximum input voltage, and whose current rating exceeds the maximum load current. Input Capacitor The input current to the step-down converter is discontinuous and requires a capacitor to supply the AC current to the step-down converter while maintaining the DC input voltage. Use low-ESR capacitors for the best performance. Ceramic capacitors are best, but tantalum or low-ESR electrolytic capacitors may also suffice. Inductor MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 12 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED For simplicity, choose an input capacitor with an RMS current rating greater than half of the maximum load current. The input capacitor (C1) can be electrolytic, tantalum, or ceramic. Electrolytic or tantalum capacitors will need a small, high-quality ceramic capacitor (0.1μF) placed as close to the IC as possible. Ceramic capacitors must have enough capacitance to prevent excessive input voltage ripple. The capacitor-incurred input voltage ripple is approximately: VIN   V  ILOAD V  OUT   1  OUT  fS  C1 VIN  VIN  Output Capacitor The output capacitor (C2) maintains the output DC voltage. Use ceramic, tantalum, or low-ESR electrolytic capacitors. Low-ESR capacitors are best at limiting the output voltage ripple. The output voltage ripple is approximately: VOUT   VOUT  VOUT   1  1      RESR  fS  L  VIN   8  fS  C2  Compensation Components The MPQ4462 employs current-mode control for easy compensation and fast transient response. The COMP pin—the output of the internal error amplifier—controls system stability and transient response. A series RC combination adds a pole-zero pair to the control system . The DC gain of the voltage feedback loop is: A VDC  RLOAD  GCS  A VEA  Where AVEA is the error amplifier voltage gain (200V/V) GCS is the current sense transconductance (9A/V), and RLOAD is the load resistor value. The system has two important poles: the compensation capacitor (C3) and the error amplifier’s output resistor; and the output capacitor and the load resistor. These poles are located at: Where L is the inductor and RESR is the output capacitor’s equivalent series resistance. fP1  GEA 2  C3  A VEA If using ceramic capacitors, the capacitance dominates the impedance at the switching frequency and contributes to the majority of the output voltage ripple. The output voltage ripple is approximately: fP2  1 2  C2  RLOAD ΔVOUT  VOUT  VOUT   1  8  fS2  L  C2  VIN  If using either tantalum or electrolytic capacitors, the ESR dominates the impedance at the switching frequency. The output ripple is approximately: ΔVOUT  VOUT  V   1  OUT fS  L  VIN    RESR  The output capacitor also affects the regulatorysystem’s stability. The MPQ4462 can be optimized for a wide range of capacitances and ESR values. VFB VOUT Where, GEA is the transconductance, 60μA/V. error amplifier’s The system has one important zero due to the compensation capacitor (C3) and the compensation resistor (R3). This zero is located at: fZ1  1 2  C3  R3 The system may have another important zero if the output capacitor is large and/or has a highESR. The zero is located at: fESR  1 2  C2  RESR In case requires a third pole set by the compensation capacitor (C6) and the MPQ4462 Rev. 1.12 www.MonolithicPower.com 5/24/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 13 MPQ4462 – 3.5A, 4MHz, 36V, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED compensation resistor (R3). This pole is located at: 1 2  C6  R3 fP3  The compensator shapes the converter transfer function for a desired loop gain. The feedback loop’s unity-gain crossover frequency is important. Lower crossover frequencies result slow line and load transient responses, while higher crossover frequencies increase system instability. For most applications, set the crossover frequency to ~0.1×fS. Table 2 lists some typical compensation-component values for standard output voltages. The component values are optimized for fast transient responses and good stability at given conditions. 3. Determine if C6 is required. Add C6 if the ESR zero of the output capacitor is located at