Sample & Buy Product Folder Support & Community Tools & Software Technical Documents LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 LMR14020-Q1 SIMPLE SWITCHER® 40 V, 2 A Step-Down Converter with 40 µA IQ 1 Features 3 Description • • The LMR14020-Q1 is a 40 V, 2 A step down regulator with an integrated high-side MOSFET. With a wide input range from 4 V to 40 V, it’s suitable for various applications from industrial to automotive for power conditioning from unregulated sources. An extended family is available in 3.5 A and 5 A options in pin-to-pin compatible packages, including LMR14030-Q1 and LMR14050-Q1. The regulator’s quiescent current is 40 µA in Sleep-mode, which is suitable for battery powered systems. An ultra-low 1 μA current in shutdown mode can further prolong battery life. A wide adjustable switching frequency range allows either efficiency or external component size to be optimized. Internal loop compensation means that the user is free from the tedious task of loop compensation design. This also minimizes the external components of the device. A precision enable input allows simplification of regulator control and system power sequencing. The device also has built-in protection features such as cycle-by-cycle current limit, thermal sensing and shutdown due to excessive power dissipation, and output overvoltage protection. 1 • • • • • • • • • • • • • • • Qualified for Automotive Applications AEC-Q100 Qualified With the Following Results: - Device Temperature Grade 1: -40 °C to 125 °C Ambient Operating Temperature Range - Device HBM ESD Classification Level H1C - Device CDM ESD Classification Level C4A 4 V to 40 V Input Range 2 A Continuous Output Current Ultra-low 40 µA Operating Quiescent Current 90 mΩ High-Side MOSFET Minimum Switch-On Time: 75 ns Current Mode Control Adjustable Switching Frequency from 200 kHz to 2.5 MHz Frequency Synchronization to External Clock Spread Spectrum Option for Reduced EMI Internal Compensation for Ease of Use High Duty Cycle Operation Supported Precision Enable Input 1 µA Shutdown Current External Soft-start Thermal, Overvoltage and Short Protection The LMR14020-Q1 is available in an 8-pin HSOIC or 10-pin WSON package with exposed pad for low thermal resistance. Device Information 2 Applications • • • • Automotive Battery Regulation Industrial Power Supplies Telecom and Datacom Systems General Purpose Wide Vin Regulation space (1) PART NUMBER PACKAGE BODY SIZE (NOM) LMR14020SQDDARQ1 HSOIC (8) 4.89 mm x 3.90 mm LMR14020SSQDDARQ1 (Spread Spectrum) HSOIC (8) 4.89 mm x 3.90 mm LMR14020QDPRRQ1 WSON (10) 4.10 mm x 4.10 mm LMR14020SQDPRRQ1 (Spread Spectrum) WSON (10) 4.10 mm x 4.10 mm (1) For all available packages, see the orderable addendum at the end of the datasheet. Simplified Schematic Efficiency vs Output Current VIN up to 40 V 100 CIN 90 VIN CBOOT 80 L RT/SYNC VOUT SW RT D RFBT COUT SS FB CSS GND RFBB 70 Efficiency (%) BOOT EN 60 50 40 30 20 10 VOUT = 5 V VOUT = 3.3 V VIN = 12 V, gSW = 1 MHz 0 0.001 0.01 0.1 IOUT (A) 1 10 D001 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 6.7 4 4 4 5 5 6 7 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions ...................... Thermal Information .................................................. Electrical Characteristics........................................... Switching Characteristics .......................................... Typical Characteristics .............................................. Detailed Description .............................................. 9 7.1 Overview ................................................................... 9 7.2 Functional Block Diagram ......................................... 9 7.3 Feature Description................................................. 10 7.4 Device Functional Modes........................................ 16 8 Application and Implementation ........................ 17 8.1 Application Information............................................ 17 8.2 Typical Application ................................................. 17 9 Power Supply Recommendations...................... 22 10 Layout................................................................... 22 10.1 Layout Guidelines ................................................. 22 10.2 Layout Example .................................................... 23 11 Device and Documentation Support ................. 24 11.1 11.2 11.3 11.4 11.5 11.6 11.7 Device Support .................................................... Documentation Support ........................................ Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 24 24 24 24 24 24 24 12 Mechanical, Packaging, and Orderable Information ........................................................... 25 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Original (November 2015) to Revision A Page • Added DPR package information ........................................................................................................................................... 1 • Added new column for WSON package................................................................................................................................. 3 • Added new row for PGOOD ................................................................................................................................................... 4 • Added new row for PGOOD ................................................................................................................................................... 4 • Added new section for PGOOD.............................................................................................................................................. 5 • Added PGOOD section ........................................................................................................................................................ 14 2 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 5 Pin Configuration and Functions DDA Package 8-Pin (HSOIC) Top View DPR Package 10-Pin (WSON) Top View BOOT 1 8 SW VIN 2 7 GND EN 3 6 SS Thermal Pad (9) 4 RT/SYNC 5 BOOT 1 VIN 2 10 SW 9 GND 8 PGOOD Thermal Pad VIN 3 EN 4 7 FB RT/SYNC 5 6 SS (11) FB Pin Functions NAME NO. TYPE (1) DESCRIPTION SO-8 WSON-10 BOOT 1 1 P Bootstrap capacitor connection for high-side MOSFET driver. Connect a high quality 0.1 μF capacitor from BOOT to SW. VIN 2 2, 3 P Connect to power supply and bypass capacitors CIN. Path from VIN pin to high frequency bypass CIN and GND must be as short as possible. EN 3 4 A Enable pin, with internal pull-up current source. Pull below 1.2 V to disable. Float or connect to VIN to enable. Adjust the input under voltage lockout with two resistors. See the Enable and Adjusting Under voltage lockout section. RT/SYNC 4 5 A Resistor Timing or External Clock input. An internal amplifier holds this pin at a fixed voltage when using an external resistor to ground to set the switching frequency. If the pin is pulled above the PLL upper threshold, a mode change occurs and the pin becomes a synchronization input. The internal amplifier is disabled and the pin is a high impedance clock input to the internal PLL. If clocking edges stop, the internal amplifier is re-enabled and the operating mode returns to frequency programming by resistor. FB 5 7 A Feedback input pin, connect to the feedback divider to set VOUT. Do not short this pin to ground during operation. SS 6 6 A Soft-start control pin. Connect to a capacitor to set soft-start time. N/A 8 A Open drain output for power-good flag. Use a 10 kΩ to 100 kΩ pull-up resistor to logic rail or other DC voltage no higher than 7V. GND 7 9 G System ground pin. SW 8 10 P Switching output of the regulator. Internally connected to high-side power MOSFET. Connect to power inductor. Thermal Pad 9 11 G Major heat dissipation path of the die. Must be connected to ground plane on PCB. PGOOD (1) A = Analog, P = Power, G = Ground Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 3 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings (1) Over the recommended operating junction temperature range of -40°C to 125°C (unless otherwise noted) Input Voltages MIN MAX VIN, EN to GND -0.3 44 BOOT to GND -0.3 49 SS to GND -0.3 5 FB to GND -0.3 7 RT/SYNC to GND -0.3 3.6 PGOOD to GND -0.3 V 7 BOOT to SW Output Voltages UNIT 6.5 V SW to GND -3 44 TJ Junction temperature -40 150 °C Tstg Storage temperature -65 150 °C (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.2 ESD Ratings VALUE V(ESD) (1) Electrostatic discharge Human-body model (HBM), per AEC Q100-002 (1) Charged-device model (CDM), per AEC Q100-011 UNIT ±2000 V ±750 AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification. 6.3 Recommended Operating Conditions Over the recommended operating junction temperature range of -40°C to 125°C (unless otherwise noted) VIN VOUT Buck Regulator Control Temperature (1) 4 MIN MAX 4 40 0.8 28 BOOT 45 SW -1 FB 0 5 EN 0 40 RT/SYNC 0 3.3 SS 0 3 PGOOD to GND Frequency (1) UNIT V 40 0 5 Switching frequency range at RT mode 200 2500 Switching frequency range at SYNC mode 250 2300 Operating junction temperature, TJ -40 125 V kHz °C Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications, see Electrical Characteristics . Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 6.4 Thermal Information LMR14020-Q1 THERMAL METRIC (1) (2) DDA (HSOIC) DPR (WSON) 8 PINS 10 PINS UNIT 42.5 36.5 °C/W RθJA Junction-to-ambient thermal resistance ψJT Junction-to-top characterization parameter 9.9 0.3 °C/W ψJB Junction-to-board characterization parameter 25.4 13.8 °C/W RθJC(top) Junction-to-case (top) thermal resistance 56.1 35.2 °C/W RθJC(bot) Junction-to-case (bottom) thermal resistance 3.8 3.1 °C/W RθJB Junction-to-board thermal resistance 25.5 13.6 °C/W (1) (2) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953. Power rating at a specific ambient temperature TA should be determined with a maximum junction temperature (TJ) of 125°C, which is illustrated in Recommended Operating Conditions section. 6.5 Electrical Characteristics Limits apply over the recommended operating junction temperature (TJ) range of -40°C to +125°C, unless otherwise stated. Minimum and Maximum limits are specified through test, design or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Unless otherwise specified, the following conditions apply: VIN = 4.0 V to 40 V PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 40 V POWER SUPPLY (VIN PIN) VIN Operation input voltage 4 UVLO Under voltage lockout thresholds Rising threshold 3.5 3.7 Hysteresis 285 ISHDN Shutdown supply current VEN = 0 V, TJ = 25 °C, 4.0 V ≤ VIN ≤ 40 V 1.0 IQ Operating quiescent current (nonswitching) VFB = 1.0 V, TJ = 25 °C 40 3.9 V mV 3.0 μA μA ENABLE (EN PIN) VEN_TH EN Threshold Voltage IEN_PIN EN PIN current IEN_HYS 1.05 1.20 Enable threshold +50 mV -4.6 Enable threshold -50 mV -1.0 EN hysteresis current 1.38 V μA -3.6 μA TJ = 25 °C -3.0 μA Power-good flag under voltage tripping threshold POWER GOOD (% of FB voltage) 94% POWER BAD (% of FB voltage) 92% Power-good flag over voltage tripping threshold POWER BAD (% of FB voltage) 109% POWER GOOD (% of FB voltage) 107% VPG_HYS Power-good flag recovery hysteresis % of FB voltage 2% IPG PGOOD leakage current at high level output VPull-Up = 5 V 10 VPG_LOW PGOOD low level output voltage IPull-Up = 1 mA 0.1 VIN_PG_MIN Minimum VIN for valid PGOOD output VPull-Up < 5 V at IPull-Up = 100 μA 1.6 1.95 V EXTERNAL SOFT-START ISS SS pin current POWER GOOD (PGOOD PIN) VPG_UV VPG_OV 200 nA V VOLTAGE REFERENCE (FB PIN) VFB Feedback voltage TJ = 25 °C 0.744 0.750 0.756 V TJ = -40 °C to 125 °C 0.735 0.750 0.765 V 90 180 mΩ HIGH-SIDE MOSFET RDS_ON On-resistance VIN = 12 V, BOOT to SW = 5.8 V Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 5 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com Electrical Characteristics (continued) Limits apply over the recommended operating junction temperature (TJ) range of -40°C to +125°C, unless otherwise stated. Minimum and Maximum limits are specified through test, design or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Unless otherwise specified, the following conditions apply: VIN = 4.0 V to 40 V PARAMETER TEST CONDITIONS MIN TYP MAX UNIT VIN = 12 V, TJ = -40 °C to 125 °C, Open Loop 2.13 3.15 4.6 A HIGH-SIDE MOSFET CURRENT LIMIT ILIMT Current limit THERMAL PERFORMANCE TSHDN Thermal shutdown threshold 170 THYS Hysteresis 12 °C 6.6 Switching Characteristics Over the recommended operating junction temperature range of -40°C to 125°C (unless otherwise noted) PARAMETER TEST CONDITIONS Switching frequency fSW RT = 11.5 kΩ Switching frequency range at SYNC mode MIN TYP MAX 1758 1912 2066 250 kHz FDITHER Switching frequency dithering VSYNC_HI SYNC clock high level threshold VSYNC_LO SYNC clock low level threshold TSYNC_MIN Minimum SYNC input pulse width Measured at 500 kHz, VSYNC_HI > 3 V, VSYNC_LO < 0.3 V 30 ns TLOCK_IN PLL lock in time Measured at 500 kHz 100 µs TON_MIN Minimum controllable on time VIN = 12 V, BOOT to SW = 5.8 V, ILoad = 1A 75 ns DMAX Maximum duty cycle fSW = 200 kHz 6 Spread spectrum option, frequency dithering over center frequency 2300 UNIT ±6% 1.7 0.5 Submit Documentation Feedback V 97% Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 6.7 Typical Characteristics 100 100 90 90 80 80 70 70 Efficiency (%) Efficiency (%) Unless otherwise specified the following conditions apply: VIN = 12 V, fSW = 1 MHz, L = 5.5 µH, COUT = 47 µF, TA = 25°C. 60 50 40 30 60 50 40 30 20 20 VIN = 12 V VIN = 24 V VIN = 36 V 10 0 0.001 0.01 VOUT = 5 V 0.1 IOUT (A) 1 VIN = 24 V VIN = 12 V VIN = 6 V 10 0 0.001 10 0.01 fSW = 1 MHz VOUT = 5 V 1 10 D003 fSW = 2.2 MHz Figure 2. Efficiency vs. Load Current 100 100 90 90 80 80 70 70 Efficiency (%) Efficiency (%) Figure 1. Efficiency vs. Load Current 60 50 40 30 60 50 40 30 20 20 VIN = 24 V VIN = 12 V VIN = 5 V 10 0 0.001 0.01 VOUT = 3.3 V 0.1 IOUT (A) 1 VIN = 20 V VIN = 12 V VIN = 5 V 10 0 0.001 10 0.01 0.1 (A) 1 10 IOUT D009 fSW = 1 MHz VOUT = 3.3 V Figure 3. Efficiency vs. Load Current D010 fSW = 2.2 MHz Figure 4. Efficiency vs. Load Current 125 0.2 Nominal Switching Frequency (%) VIN = 36 V VIN = 24 V VIN = 12 V 0.15 VOUT Deviation (%) 0.1 IOUT (A) D002 0.1 0.05 0 -0.05 -0.1 -0.15 0.001 VOUT = 5 V VFB Falling VFB Rising 100 75 50 25 0 0.01 0.1 IOUT (A) 1 10 0 0.1 D004 0.2 0.3 0.4 VFB (V) 0.5 0.6 0.7 D005 fSW = 1 MHz Figure 5. Load Regulation Figure 6. Frequency vs VFB Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 7 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com Typical Characteristics (continued) 6 6 5.5 5.5 5 5 4.5 4.5 VOUT (V) VOUT (V) Unless otherwise specified the following conditions apply: VIN = 12 V, fSW = 1 MHz, L = 5.5 µH, COUT = 47 µF, TA = 25°C. 4 3.5 4 3.5 3 3 IOUT = 2 A IOUT = 1 A IOUT = 0.2 A 2.5 IOUT = 2 A IOUT = 1 A IOUT = 0.2 A 2.5 2 2 4 4.5 5 5.5 6 6.5 VIN (V) VOUT = 5 V 4 4.5 5.5 6 fSW = 1 MHz VOUT = 5 V D012 fSW = 2.2 MHz Figure 8. Dropout Curve 3.6 3.3 3.3 VOUT (V) 3.6 3 2.7 3 2.7 IOUT = 2 A IOUT = 1 A IOUT = 0.2 A 2.4 3.5 3.75 4 VOUT = 3.3 V IOUT = 2 A IOUT = 1 A IOUT = 0.2 A 2.4 3.5 4.25 VIN (V) 3.75 4 4.25 VIN (V) D013 fSW = 1 MHz VOUT = 3.3 V Figure 9. Dropout Curve D014 fSW = 2.2 MHz Figure 10. Dropout Curve 45 3.75 40 3.7 IQ 35 UVLO_H 3.65 30 UVLO (V) IQ & ISHDN (µA) 6.5 VIN (V) Figure 7. Dropout Curve VOUT (V) 5 D011 25 20 15 3.6 3.55 3.5 UVLO_L 10 ISHDN 5 3.45 0 0 5 10 15 20 25 VIN (V) 30 35 40 45 3.4 -50 -25 0 D006 25 50 75 Temperature (°C) 100 125 150 D007 IOUT = 0 A Figure 11. Shut-down Current and Quiescent Current 8 Submit Documentation Feedback Figure 12. UVLO Threshold Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 7 Detailed Description 7.1 Overview The LMR14020-Q1 SIMPLE SWITCHER® regulator is an easy to use step-down DC-DC converter that operates from a 4.0 V to 40 V supply voltage. It integrates a 90 mΩ (typical) high-side MOSFET, and is capable of delivering up to 2 A DC load current with exceptional efficiency and thermal performance in a very small solution size. The operating current is typically 40 μA under no load condition (not switching). When the device is disabled, the supply current is typically 1 μA. An extended family is available in 3.5 A and 5 A load options in pin to pin compatible packages. The LMR14020-Q1 implements constant frequency peak current mode control with Sleep-mode at light load to achieve high efficiency. The device is internally compensated, which reduces design time, and requires fewer external components. The switching frequency is programmable from 200 kHz to 2.5 MHz by an external resistor RT. The LMR14020-Q1 is also capable of synchronization to an external clock within the 250 kHz to 2.3 MHz frequency range, which allows the device to be optimized to fit small board space at higher frequency, or high efficient power conversion at lower frequency. Other features are included for more comprehensive system requirements, including precision enable, adjustable soft-start time, and approximate 97% duty cycle by BOOT capacitor recharge circuit. These features provide a flexible and easy to use platform for a wide range of applications. Protection features include over temperature shutdown, VOUT over voltage protection (OVP), VIN under-voltage lockout (UVLO), cycle-by-cycle current limit, and short-circuit protection with frequency fold-back. 7.2 Functional Block Diagram EN VIN Enable Comparator Thermal Shutdown UVLO Shutdown Shutdown Logic Voltage Reference Enable Threshold Boot Charge OV Boot UVLO FB ERROR AMPLIFIER Shutdown PWM Comparator BOOT PWM Control Logic Comp Components 6 Slope Compensation SW Frequency Shift Bootstrap Control VIN Oscillator with PLL SS GND RT/SYNC Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 9 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com 7.3 Feature Description 7.3.1 Fixed Frequency Peak Current Mode Control The following operating description of the LMR14020-Q1 will refer to the Functional Block Diagram and to the waveforms in Figure 13. LMR14020-Q1 output voltage is regulated by turning on the high-side N-MOSFET with controlled ON time. During high-side switch ON time, the SW pin voltage swings up to approximately VIN, and the inductor current iL increase with linear slope (VIN – VOUT) / L. When high-side switch is off, inductor current discharges through freewheel diode with a slope of –VOUT / L. The control parameter of Buck converter is defined as Duty Cycle D = tON / TSW, where tON is the high-side switch ON time and TSW is the switching period. The regulator control loop maintains a constant output voltage by adjusting the duty cycle D. In an ideal Buck converter, where losses are ignored, D is proportional to the output voltage and inversely proportional to the input voltage: D = VOUT / VIN. VSW SW Voltage D = tON/ TSW VIN tON tOFF t 0 -VD Inductor Current iL TSW ILPK IOUT ûiL t 0 Figure 13. SW Node and Inductor Current Waveforms in Continuous Conduction Mode (CCM) The LMR14020-Q1 employs fixed frequency peak current mode control. A voltage feedback loop is used to get accurate DC voltage regulation by adjusting the peak current command based on voltage offset. The peak inductor current is sensed from the high-side switch and compared to the peak current to control the ON time of the high-side switch. The voltage feedback loop is internally compensated, which allows for fewer external components, makes it easy to design, and provides stable operation with almost any combination of output capacitors. The regulator operates with fixed switching frequency at normal load condition. At very light load, the LMR14020-Q1 will operate in Sleep-mode to maintain high efficiency and the switching frequency will decrease with reduced load current. 7.3.2 Slope Compensation The LMR14020-Q1 adds a compensating ramp to the MOSFET switch current sense signal. This slope compensation prevents sub-harmonic oscillations at duty cycles greater than 50%. The peak current limit of the high-side switch is not affected by the slope compensation and remains constant over the full duty cycle range. 7.3.3 Sleep-mode The LMR14020-Q1 operates in Sleep-mode at light load currents to improve efficiency by reducing switching and gate drive losses. If the output voltage is within regulation and the peak switch current at the end of any switching cycle is below the current threshold of 300 mA, the device enters Sleep-mode. The Sleep-mode current threshold is the peak switch current level corresponding to a nominal internal COMP voltage of 400 mV. When in Sleep-mode, the internal COMP voltage is clamped at 400 mV and the high-side MOSFET is inhibited, and the device draws only 40 μA (typical) input quiescent current. Since the device is not switching, the output voltage begins to decay. The voltage control loop responds to the falling output voltage by increasing the internal COMP voltage. The high-side MOSFET is enabled and switching resumes when the error amplifier lifts internal COMP voltage above 400 mV. The output voltage recovers to the regulated value, and internal COMP voltage eventually falls below the Sleep-mode threshold at which time the device again enters Sleep-mode. 10 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 Feature Description (continued) 7.3.4 Low Dropout Operation and Bootstrap Voltage (BOOT) The LMR14020-Q1 provides an integrated bootstrap voltage regulator. A small capacitor between the BOOT and SW pins provides the gate drive voltage for the high-side MOSFET. The BOOT capacitor is refreshed when the high-side MOSFET is off and the external low side diode conducts. The recommended value of the BOOT capacitor is 0.1 μF. A ceramic capacitor with an X7R or X5R grade dielectric with a voltage rating of 16 V or greater is recommended for stable performance over temperature and voltage. When operating with a low voltage difference from input to output, the high-side MOSFET of the LMR14020-Q1 will operate at approximate 97% duty cycle. When the high-side MOSFET is continuously on for 5 or 6 switching cycles (5 or 6 switching cycles for frequency lower than 1 MHz, and 10 or 11 switching cycles for frequency higher than 1 MHz) and the voltage from BOOT to SW drops below 3.2 V, the high-side MOSFET is turned off and an integrated low side MOSFET pulls SW low to recharge the BOOT capacitor. Since the gate drive current sourced from the BOOT capacitor is small, the high-side MOSFET can remain on for many switching cycles before the MOSFET is turned off to refresh the capacitor. Thus the effective duty cycle of the switching regulator can be high, approaching 97%. The effective duty cycle of the converter during dropout is mainly influenced by the voltage drops across the power MOSFET, the inductor resistance, the low side diode voltage and the printed circuit board resistance. 7.3.5 Adjustable Output Voltage The internal voltage reference produces a precise 0.75 V (typical) voltage reference over the operating temperature range. The output voltage is set by a resistor divider from output voltage to the FB pin. It is recommended to use 1% tolerance or better and temperature coefficient of 100 ppm or less divider resistors. Select the low side resistor RFBB for the desired divider current and use Equation 1 to calculate high-side RFBT. Larger value divider resistors are good for efficiency at light load. However, if the values are too high, the regulator will be more susceptible to noise and voltage errors from the FB input current may become noticeable. RFBB in the range from 10 kΩ to 100 kΩ is recommended for most applications. VOUT RFBT FB RFBB Figure 14. Output Voltage Setting RFBT VOUT 0.75 u RFBB 0.75 (1) 7.3.6 Enable and Adjustable Under-voltage Lockout The LMR14020-Q1 is enabled when the VIN pin voltage rises above 3.7 V (typical) and the EN pin voltage exceeds the enable threshold of 1.2 V (typical). The LMR14020-Q1 is disabled when the VIN pin voltage falls below 3.42 V (typical) or when the EN pin voltage is below 1.2 V. The EN pin has an internal pull-up current source (typically IEN = 1 μA) that enables operation of the LMR14020-Q1 when the EN pin is floating. Many applications will benefit from the employment of an enable divider RENT and RENB in Figure 15 to establish a precision system UVLO level for the stage. System UVLO can be used for supplies operating from utility power as well as battery power. It can be used for sequencing, ensuring reliable operation, or supply protection, such as a battery. An external logic signal can also be used to drive EN input for system sequencing and protection. When EN terminal voltage exceeds 1.2 V, an additional hysteresis current (typically IHYS = 3.6 μA) is sourced out of EN terminal. When the EN terminal is pulled below 1.2 V, IHYS current is removed. This additional current facilitates adjustable input voltage UVLO hysteresis. Use Equation 2 and Equation 3 to calculate RENT and RENB for desired UVLO hysteresis voltage. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 11 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com Feature Description (continued) IEN_HYS IEN VIN VIN RENT VEN EN RENB Figure 15. System UVLO By Enable Dividers RENT RENB VSTART VSTOP IHYS VEN VSTART VEN RENT (2) IEN (3) where VSTART is the desired voltage threshold to enable LMR14020-Q1, VSTOP is the desired voltage threshold to disable device. 7.3.7 External Soft-start The LMR14020-Q1 has soft-start pin for programmable output ramp up time. The soft-start feature is used to prevent inrush current impacting the LMR14020-Q1 and its load when power is first applied. The soft-start time can be programed by connecting an external capacitor CSS from SS pin to GND. An internal current source (typically ISS = 3 μA) charges CSS and generates a ramp from 0 V to VREF. The soft-start time can be calculated by Equation 4: CSS (nF) u VREF (V) tSS (ms) ISS (PA) (4) For LMR14020-Q1 in WSON package, the maximum value of CSS is 4.7 nF. The soft-start resets while device is disabled or in thermal shutdown. 7.3.8 Switching Frequency and Synchronization (RT/SYNC) The switching frequency of the LMR14020-Q1 can be programmed by the resistor RT from the RT/SYNC pin and GND pin. The RT/SYNC pin can’t be left floating or shorted to ground. To determine the timing resistance for a given switching frequency, use Equation 5 or the curve in Figure 16. Table 1 gives typical RT values for a given fSW. RT (k:) 12 42904 u ¦SW N+] 1.088 (5) Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 Feature Description (continued) 140 120 RT (k:) 100 80 60 40 20 0 0 500 1000 1500 Frequency (kHz) 2000 2500 D008 Figure 16. RT vs Frequency Curve Table 1. Typical Frequency Setting RT Resistance fSW (kHz) RT (kΩ) 200 133 350 73.2 500 49.9 750 32.4 1000 23.2 1500 15.0 1912 11.5 2200 9.76 The LMR14020-Q1 switching action can also be synchronized to an external clock from 250 kHz to 2.3 MHz. Connect a square wave to the RT/SYNC pin through either circuit network shown in Figure 17. Internal oscillator is synchronized by the falling edge of external clock. The recommendations for the external clock include: high level no lower than 1.7 V, low level no higher than 0.5 V and have a pulse width greater than 30 ns. When using a low impedance signal source, the frequency setting resistor RT is connected in parallel with an AC coupling capacitor CCOUP to a termination resistor RTERM (e.g., 50 Ω). The two resistors in series provide the default frequency setting resistance when the signal source is turned off. A 10 pF ceramic capacitor can be used for CCOUP. Figure 18, Figure 19 and Figure 20 show the device synchronized to an external system clock. CCOUP PLL PLL Lo-Z Clock Source RT RT/SYNC RTERM Hi-Z Clock Source RT/SYNC RT Figure 17. Synchronizing to an External Clock Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 13 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com SYNC (2 V/DIV) SYNC (2 V/DIV) SW (5 V/DIV) SW (5 V/DIV) iL (1 A/DIV) iL (500 mA/DIV) Time (1 µs/DIV) Time (1 µs/DIV) Figure 18. Synchronizing in CCM Figure 19. Synchronizing in DCM SYNC (2 V/DIV) SW (5 V/DIV) iL (500 mA/DIV) Time (4 µs/DIV) Figure 20. Synchronizing in Sleep-mode Mode For spread spectrum option, the internal frequency dithering is disabled if the device is synchronized to an external clock. Equation 6 calculates the maximum switching frequency limitation set by the minimum controllable on time and the input to output step down ratio. Setting the switching frequency above this value will cause the regulator to skip switching pulses to achieve the low duty cycle required at maximum input voltage. ¦SW(max) § IOUT u RIND VOUT VD · u¨ ¸ tON ¨© VIN_MAX IOUT u RDS_ON VD ¸¹ 1 (6) where • IOUT = Output current • RIND = Inductor series resistance • VIN_MAX = Maximum input voltage • VOUT = Output voltage • VD = Diode voltage drop • RDS_ON = High-side MOSFET switch on resistance • tON = Minimum on time 7.3.9 Power Good (PGOOD) The LMR14020-Q1 in WSON-10 package has a built in power-good flag shown on PGOOD pin to indicate whether the output voltage is within its regulation level. The PGOOD signal can be used for start-up sequencing of multiple rails or fault protection. The PGOOD pin is an open-drain output that requires a pull-up resistor to an appropriate DC voltage. Voltage seen by the PGOOD pin should never exceed 7 V. A resistor divider pair can be used to divide the voltage down from a higher potential. A typical range of pull-up resistor value is 10 kΩ to 100 kΩ. 14 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 Refer to Figure 21. When the FB voltage is within the power-good band, +7% above and -6% below the internal reference VREF typically, the PGOOD switch will be turned off and the PGOOD voltage will be pulled up to the voltage level defined by the pull-up resistor or divider. When the FB voltage is outside of the tolerance band, +9% above or -8% below VREF typically, the PGOOD switch will be turned on and the PGOOD pin voltage will be pulled low to indicate power bad. VREF 109% 107% 94% 92% PGOOD High Low Figure 21. Power-Good Flag 7.3.10 Over Current and Short Circuit Protection The LMR14020-Q1 is protected from over current condition by cycle-by-cycle current limiting on the peak current of the high-side MOSFET. High-side MOSFET over-current protection is implemented by the nature of the Peak Current Mode control. The high-side switch current is compared to the output of the Error Amplifier (EA) minus slope compensation every switching cycle. Please refer to Functional Block Diagram for more details. The peak current of high-side switch is limited by a clamped maximum peak current threshold which is constant. So the peak current limit of the high-side switch is not affected by the slope compensation and remains constant over the full duty cycle range. The LMR14020-Q1 also implements a frequency fold-back to protect the converter in severe over-current or short conditions. The oscillator frequency is divided by 2, 4, and 8 as the FB pin voltage decrease to 75%, 50%, 25% of VREF. The frequency fold-back increases the off time by increasing the period of the switching cycle, so that it provides more time for the inductor current to ramp down and leads to a lower average inductor current. Lower frequency also means lower switching loss. Frequency fold-back reduces power dissipation and prevents overheating and potential damage to the device. 7.3.11 Overvoltage Protection The LMR14020-Q1 employs an output overvoltage protection (OVP) circuit to minimize voltage overshoot when recovering from output fault conditions or strong unload transients in designs with low output capacitance. The OVP feature minimizes output overshoot by turning off high-side switch immediately when FB voltage reaches to the rising OVP threshold which is nominally 109% of the internal voltage reference VREF. When the FB voltage drops below the falling OVP threshold which is nominally 107% of VREF, the high-side MOSFET resumes normal operation. 7.3.12 Thermal Shutdown The LMR14020-Q1 provides an internal thermal shutdown to protect the device when the junction temperature exceeds 170 °C (typical). The high-side MOSFET stops switching when thermal shundown activates. Once the die temperature falls below 158 °C (typical), the device reinitiates the power up sequence controlled by the internal soft-start circuitry. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 15 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com 7.4 Device Functional Modes 7.4.1 Shutdown Mode The EN pin provides electrical ON and OFF control for the LMR14020-Q1. When VEN is below 1.0 V, the device is in shutdown mode. The switching regulator is turned off and the quiescent current drops to 1.0 µA typically. The LMR14020-Q1 also employs under voltage lock out protection. If VIN voltage is below the UVLO level, the regulator will be turned off. 7.4.2 Active Mode The LMR14020-Q1 is in Active Mode when VEN is above the precision enable threshold and VIN is above its UVLO level. The simplest way to enable the LMR14020-Q1 is to connect the EN pin to VIN pin. This allows self startup when the input voltage is in the operation range: 4.0 V to 40 V. Please refer to Enable and Adjustable Under-voltage Lockout for details on setting these operating levels. In Active Mode, depending on the load current, the LMR14020-Q1 will be in one of three modes: 1. Continuous conduction mode (CCM) with fixed switching frequency when load current is above half of the peak-to-peak inductor current ripple. 2. Discontinuous conduction mode (DCM) with fixed switching frequency when load current is lower than half of the peak-to-peak inductor current ripple in CCM operation. 3. Sleep-mode when internal COMP voltage drop to 400 mV at very light load. 7.4.3 CCM Mode CCM operation is employed in the LMR14020-Q1 when the load current is higher than half of the peak-to-peak inductor current. In CCM operation, the frequency of operation is fixed, output voltage ripple will be at a minimum in this mode and the maximum output current of 2 A can be supplied by the LMR14020-Q1. 7.4.4 Light Load Operation When the load current is lower than half of the peak-to-peak inductor current in CCM, the LMR14020-Q1 will operate in DCM. At even lighter current loads, Sleep-mode is activated to maintain high efficiency operation by reducing switching and gate drive losses. 16 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information The LMR14020-Q1 is a step down DC-to-DC regulator. It is typically used to convert a higher DC voltage to a lower DC voltage with a maximum output current of 2 A. The following design procedure can be used to select components for the LMR14020-Q1. This section presents a simplified discussion of the design process. 8.2 Typical Application The LMR14020-Q1 only requires a few external components to convert from wide voltage range supply to a fixed output voltage. A schematic of 5 V / 2 A application circuit based on LMR14020-Q1 in SO-8 package is shown in Figure 22. The external components have to fulfill the needs of the application, but also the stability criteria of the device’s control loop. 7 V to 36 V VIN CIN CBOOT BOOT L EN 5V/2A SW COUT D RFBT RT/SYNC FB RFBB SS RT GND CSS Figure 22. Application Circuit, 5V Output 8.2.1 Design Requirements This example details the design of a high frequency switching regulator using ceramic output capacitors. A few parameters must be known in order to start the design process. These parameters are typically determined at the system level: Table 2. Design Parameters Input Voltage, VIN 7 V to 36 V, Typical 12 V Output Voltage, VOUT 5.0 V Maximum Output Current IO_MAX 2A Transient Response 0.2 A to 2 A 5% Output Voltage Ripple 50 mV Input Voltage Ripple 400 mV Switching Frequency fSW 1 MHz Soft-start time 5 ms Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 17 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com 8.2.2 Detailed Design Procedure 8.2.2.1 Output Voltage Set-Point The output voltage of LMR14020-Q1 is externally adjustable using a resistor divider network. The divider network is comprised of top feedback resistor RFBT and bottom feedback resistor RFBB. Equation 7 is used to determine the output voltage: VOUT 0.75 RFBT u RFBB 0.75 (7) Choose the value of RFBT to be 100 kΩ. With the desired output voltage set to 5 V and the VFB = 0.75 V, the RFBB value can then be calculated using Equation 7. The formula yields to a value 17.65 kΩ. Choose the closest available value of 17.8 kΩ for RFBB. 8.2.2.2 Switching Frequency For desired frequency, use Equation 8 to calculate the required value for RT. RT (k:) 42904 u ¦SW N+] 1.088 (8) For 1 MHz, the calculated RT is 23.36 kΩ and standard value 23.2 kΩ can be used to set the switching frequency at 1 MHz. 8.2.2.3 Output Inductor Selection The most critical parameters for the inductor are the inductance, saturation current and the RMS current. The inductance is based on the desired peak-to-peak ripple current ΔiL. Since the ripple current increases with the input voltage, the maximum input voltage is always used to calculate the minimum inductance LMIN. Use Equation 9 to calculate the minimum value of the output inductor. KIND is a coefficient that represents the amount of inductor ripple current relative to the maximum output current. A reasonable value of KIND should be 20%-40%. During an instantaneous short or over current operation event, the RMS and peak inductor current can be high. The inductor current rating should be higher than current limit. VOUT u (VIN_MAX VOUT ) 'iL VIN _ MAX u L u ¦SW (9) LMIN VIN_MAX VOUT IOUT u KIND u VOUT VIN_MAX u ¦SW (10) In general, it is preferable to choose lower inductance in switching power supplies, because it usually corresponds to faster transient response, smaller DCR, and reduced size for more compact designs. But too low of an inductance can generate too large of an inductor current ripple such that over current protection at the full load could be falsely triggered. It also generates more conduction loss since the RMS current is slightly higher. Larger inductor current ripple also implies larger output voltage ripple with same output capacitors. With peak current mode control, it is not recommended to have too small of an inductor current ripple. A larger peak current ripple improves the comparator signal to noise ratio. For this design example, choose KIND = 0.4, the minimum inductor value is calculated to be 5.38 µH, and a nearest standard value is chosen: 5.5 µH. A standard 5.5 μH ferrite inductor with a capability of 2.5 A RMS current and 4 A saturation current can be used. 8.2.2.4 Output Capacitor Selection The output capacitor(s), COUT, should be chosen with care since it directly affects the steady state output voltage ripple, loop stability and the voltage over/undershoot during load current transients. The output ripple is essentially composed of two parts. One is caused by the inductor current ripple going through the Equivalent Series Resistance (ESR) of the output capacitors: 'VOUT_ESR 'iL u ESR KIND u IOUT u ESR (11) The other is caused by the inductor current ripple charging and discharging the output capacitors: KIND u IOUT 'iL 'VOUT_C 8 u ¦SW u COUT 8 u ¦SW u COUT 18 Submit Documentation Feedback (12) Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 The two components in the voltage ripple are not in phase, so the actual peak-to-peak ripple is smaller than the sum of two peaks. Output capacitance is usually limited by transient performance specifications if the system requires tight voltage regulation with presence of large current steps and fast slew rate. When a fast large load increase happens, output capacitors provide the required charge before the inductor current can slew up to the appropriate level. The regulator’s control loop usually needs three or more clock cycles to respond to the output voltage droop. The output capacitance must be large enough to supply the current difference for three clock cycles to maintain the output voltage within the specified range. Equation 13 shows the minimum output capacitance needed for specified output undershoot. When a sudden large load decrease happens, the output capacitors absorb energy stored in the inductor. The catch diode can’t sink current so the energy stored in the inductor results in an output voltage overshoot. Equation 14 calculates the minimum capacitance required to keep the voltage overshoot within a specified range. 3 u (IOH IOL ) COUT ! ¦SW u 9US (13) COUT ! 2 2 IOH IOL (VOUT VOS )2 2 VOUT uL (14) where • KIND = Ripple ratio of the inductor ripple current (ΔiL / IOUT) • IOL = Low level output current during load transient • IOH = High level output current during load transient • VUS = Target output voltage undershoot • VOS = Target output voltage overshoot For this design example, the target output ripple is 50 mV. Presuppose ΔVOUT_ESR = ΔVOUT_C = 50 mV, and chose KIND = 0.4. Equation 11 yields ESR no larger than 62.5 mΩ and Equation 12 yields COUT no smaller than 2 μF. For the target over/undershoot range of this design, VUS = VOS = 5% × VOUT = 250 mV. The COUT can be calculated to be no smaller than 21.6 μF and 8.5 μF by Equation 13 and Equation 14 respectively. For stability consideration, one 47 μF output capacitor is needed at least. In summary, the most stringent criteria for the output capacitor is 47 μF. One 47 μF, 16 V, X7R ceramic capacitors with 5 mΩ ESR is used. 8.2.2.5 Schottky Diode Selection The breakdown voltage rating of the diode is preferred to be 25% higher than the maximum input voltage. The current rating for the diode should be equal to the maximum output current for best reliability in most applications. In cases where the input voltage is much greater than the output voltage the average diode current is lower. In this case it is possible to use a diode with a lower average current rating, approximately (1-D) × IOUT however the peak current rating should be higher than the maximum load current. A 2 A rated diode is a good starting point. 8.2.2.6 Input Capacitor Selection The LMR14020-Q1 device requires high frequency input decoupling capacitor(s) and a bulk input capacitor, depending on the application. The typical recommended value for the high frequency decoupling capacitor is 4.7 μF to 10 μF. A high-quality ceramic capacitor type X5R or X7R with sufficiency voltage rating is recommended. To compensate the derating of ceramic capacitors, a voltage rating of twice the maximum input voltage is recommended. Additionally, some bulk capacitance can be required, especially if the LMR14020-Q1 circuit is not located within approximately 5 cm from the input voltage source. This capacitor is used to provide damping to the voltage spike due to the lead inductance of the cable or the trace. For this design, two 2.2 μF, X7R ceramic capacitors rated for 100 V are used. A 0.1 μF for high-frequency filtering and place it as close as possible to the device pins. 8.2.2.7 Bootstrap Capacitor Selection Every LMR14020-Q1 design requires a bootstrap capacitor (CBOOT). The recommended capacitor is 0.1 μF and rated 16 V or higher. The bootstrap capacitor is located between the SW pin and the BOOT pin. The bootstrap capacitor must be a high-quality ceramic type with an X7R or X5R grade dielectric for temperature stability. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 19 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 8.2.2.8 www.ti.com Soft-start Capacitor Selection Use Equation 15 in order to calculate the soft-start capacitor value: t (ms) u ISS (PA) CSS (nF) SS VREF (V) (15) where • CSS = Soft-start capacitor value • ISS = Soft-start charging current (3 μA) • tSS = Desired soft-start time For the desired soft-start time of 5 ms and soft-start charging current of 3.0 μA, the Equation 15 yields a soft-start capacitor value of 20 nF, a standard 22 nF ceramic capacitor is used. For LMR14020-Q1 in WSON package, the maximum value of CSS is 4.7 nF. 8.2.3 Application Curves Unless otherwise specified the following conditions apply: VIN = 12 V, fSW = 1 MHz, L = 5.5 µH, COUT = 47 µF, TA = 25 °C. VIN (5 V/DIV) VIN (5 V/DIV) EN (1 V/DIV) VOUT (1 V/DIV) VOUT (1 V/DIV) iL (1 A/DIV) Time (2 ms/DIV) VIN = 12 V VOUT = 5 V Time (2 ms/DIV) IOUT = 1 A VIN = 12 V Figure 23. Start-up By EN SW (5 V/DIV) SW (5 V/DIV) iL (500 mA/DIV) iL (500 mA/DIV) VOUT(ac) (10 mV/DIV) VOUT(ac) (10 mV/DIV) VIN = 12 V VOUT = 5 V IOUT = 1 A Figure 24. Start-up By VIN Time (2 ms/DIV) Time (1 µs/DIV) IOUT = 0 A VIN = 12 V Figure 25. Sleep-mode 20 VOUT = 5 V VOUT = 5 V IOUT = 100 mA Figure 26. DCM Mode Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 Unless otherwise specified the following conditions apply: VIN = 12 V, fSW = 1 MHz, L = 5.5 µH, COUT = 47 µF, TA = 25 °C. SW (5 V/DIV) IOUT (1 A/DIV) iL (1 A/DIV) VOUT(ac) (200 mV/DIV) VOUT(ac) (10 mV/DIV) Time (1 µs/DIV) VIN = 12 V VOUT = 5 V Time (100 µs/DIV) IOUT = 2 A IOUT: 10% → 100% of 2 A Slew rate = 100 mA/μs Figure 27. CCM Mode Figure 28. Load Transient VOUT (2 V/DIV) VOUT (2 V/DIV) iL (1 A/DIV) iL (1 A/DIV) Time (40 µs/DIV) VIN = 12 V VOUT = 5 V Time (1.6 ms/DIV) VIN = 12 V Figure 29. Output Short VOUT = 5 V Figure 30. Output Short Recovery Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 21 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com 9 Power Supply Recommendations The LMR14020-Q1 is designed to operate from an input voltage supply range between 4 V and 40 V. This input supply should be able to withstand the maximum input current and maintain a stable voltage. The resistance of the input supply rail should be low enough that an input current transient does not cause a high enough drop at the LMR14020-Q1 supply voltage that can cause a false UVLO fault triggering and system reset. If the input supply is located more than a few inches from the LMR14020-Q1, additional bulk capacitance may be required in addition to the ceramic input capacitors. The amount of bulk capacitance is not critical, but a 22 μF or 47 μF electrolytic capacitor is a typical choice . 10 Layout 10.1 Layout Guidelines Layout is a critical portion of good power supply design. The following guidelines will help users design a PCB with the best power conversion performance, thermal performance, and minimized generation of unwanted EMI. 1. The feedback network, resistor RFBT and RFBB, should be kept close to the FB pin. VOUT sense path away from noisy nodes and preferably through a layer on the other side of a shielding layer. 2. The input bypass capacitor CIN must be placed as close as possible to the VIN pin and ground. Grounding for both the input and output capacitors should consist of localized top side planes that connect to the GND pin and PAD. 3. The inductor L should be placed close to the SW pin to reduce magnetic and electrostatic noise. 4. The output capacitor, COUT should be placed close to the junction of L and the diode D. The L, D, and COUT trace should be as short as possible to reduce conducted and radiated noise and increase overall efficiency. 5. The ground connection for the diode, CIN, and COUT should be as small as possible and tied to the system ground plane in only one spot (preferably at the COUT ground point) to minimize conducted noise in the system ground plane. 6. For more detail on switching power supply layout considerations see SNVA021 Application Note AN-1149. 22 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 10.2 Layout Example Output Bypass Capacitor Output Inductor Rectifier Diode BOOT Capacitor Input Bypass Capacitor BOOT UVLO Adjust Resistor SW VIN GND EN SS RT/SYNC FB Soft-Start Capacitor Output Voltage Set Resistor Frequency Set Resistor Thermal VIA Signal VIA Figure 31. Layout Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 23 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 www.ti.com 11 Device and Documentation Support 11.1 Device Support 11.1.1 Third-Party Products Disclaimer TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE. 11.2 Documentation Support 11.2.1 Related Documentation For related documentation see the following: • AN-1149 Layout Guidelines for Switching Power Supplies ( SNVA021). 11.2.2 Related Product Part Number VIN (V) IOUT (A) Comments LMR14030-Q1 4.0 - 40 3.5 Non-synchronous Step-down Converter, IQ = 40 µA, Sleep-mode, Spread Spectrum, SO-8 or WSON-10 Package LMR14050-Q1 4.0 - 40 5 Non-synchronous Step-down Converter, IQ = 40 µA, Sleep-mode, Spread Spectrum, SO-8 or WSON-10 Package 11.3 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 11.4 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 11.5 Trademarks E2E is a trademark of Texas Instruments. SIMPLE SWITCHER is a registered trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.6 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 11.7 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 24 Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 LMR14020-Q1 www.ti.com SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 25 LMR14020-Q1 SNVSAG4A – NOVEMBER 2015 – REVISED JULY 2016 26 www.ti.com Submit Documentation Feedback Copyright © 2015–2016, Texas Instruments Incorporated Product Folder Links: LMR14020-Q1 PACKAGE OPTION ADDENDUM www.ti.com 2-Aug-2016 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) LMR14020QDPRRQ1 ACTIVE WSON DPR 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 125 LMR 14020Q LMR14020QDPRTQ1 ACTIVE WSON DPR 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 125 LMR 14020Q LMR14020SQDDAQ1 ACTIVE SO PowerPAD DDA 8 75 Green (RoHS & no Sb/Br) CU NIPDAUAG Level-2-260C-1 YEAR -40 to 125 14020Q LMR14020SQDDARQ1 ACTIVE SO PowerPAD DDA 8 2500 Green (RoHS & no Sb/Br) CU NIPDAUAG Level-2-260C-1 YEAR -40 to 125 14020Q LMR14020SQDPRRQ1 ACTIVE WSON DPR 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 125 LMR 1402SQ LMR14020SQDPRTQ1 ACTIVE WSON DPR 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 125 LMR 1402SQ LMR14020SSQDDAQ1 ACTIVE SO PowerPAD DDA 8 75 Green (RoHS & no Sb/Br) CU NIPDAUAG Level-2-260C-1 YEAR -40 to 125 1402SQ LMR14020SSQDDARQ1 ACTIVE SO PowerPAD DDA 8 2500 Green (RoHS & no Sb/Br) CU NIPDAUAG Level-2-260C-1 YEAR -40 to 125 1402SQ (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com (4) 2-Aug-2016 There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. 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OTHER QUALIFIED VERSIONS OF LMR14020-Q1 : • Catalog: LMR14020 NOTE: Qualified Version Definitions: • Catalog - TI's standard catalog product Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 29-Jul-2016 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing LMR14020QDPRRQ1 WSON DPR 10 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 3000 330.0 12.4 4.25 4.25 1.15 8.0 12.0 Q2 LMR14020QDPRTQ1 WSON DPR 10 250 180.0 12.4 4.25 4.25 1.15 8.0 12.0 Q2 LMR14020SQDDARQ1 SO Power PAD DDA 8 2500 330.0 12.8 6.4 5.2 2.1 8.0 12.0 Q1 LMR14020SQDPRRQ1 WSON DPR 10 3000 330.0 12.4 4.25 4.25 1.15 8.0 12.0 Q2 LMR14020SQDPRTQ1 WSON DPR 10 250 180.0 12.4 4.25 4.25 1.15 8.0 12.0 Q2 LMR14020SSQDDARQ1 SO Power PAD DDA 8 2500 330.0 12.8 6.4 5.2 2.1 8.0 12.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 29-Jul-2016 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMR14020QDPRRQ1 WSON DPR 10 3000 367.0 367.0 35.0 LMR14020QDPRTQ1 WSON DPR 10 250 210.0 185.0 35.0 LMR14020SQDDARQ1 SO PowerPAD DDA 8 2500 366.0 364.0 50.0 LMR14020SQDPRRQ1 WSON DPR 10 3000 367.0 367.0 35.0 LMR14020SQDPRTQ1 WSON DPR 10 250 210.0 185.0 35.0 LMR14020SSQDDARQ1 SO PowerPAD DDA 8 2500 366.0 364.0 50.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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