FEATURES TYPICAL APPLICATION CIRCUIT Input start-up voltage range: 2.15 V to 6.50 V Operates down to 2.00 V voltage Ultralow 180 nA quiescent current with no load Selectable output voltage of 1.2 V to 3.6 V or 0.8 V to 5.0 V 1.5% output accuracy over full temperature range in PWM mode Selectable hysteresis mode or PWM operation mode Output current Up to 50 mA in hysteresis mode Up to 500 mA in PWM mode VOUTOK flag monitors the output voltage 100% duty cycle operation mode 2 MHz switching frequency with optional synchronization input from 1.5 MHz to 2.5 MHz QOD option UVLO, OCP, and TSD protection 9-ball, 1.65 mm x 1.87 mm WLCSP -40C to +125C junction temperature VIN = 3.6V 2.2H 10F ADP5301 10F (9-BALL WLCSP) ON OFF PWM HYS VOUT SW PVIN EN PGND SYNC/ MODE 13169-001 Data Sheet 50 mA/500 mA, High Efficiency, Ultralow Power Step-Down Regulator ADP5301 FB VOUTOK VID RVID AGND VID0: 1.2V VID1: 1.5V VID2: 1.8V VID3: 2.0V VID4: 2.1V VID5: 2.2V VID6: 2.3V VID7: 2.4V VID8: 2.5V VID9: 2.6V VID10: 2.7V VID11: 2.8V VID12: 2.9V VID13: 3.0V VID14: 3.3V VID15: 3.6V Figure 1. APPLICATIONS Energy (gas and water) metering Portable and battery-powered equipment Medical applications Keep-alive power supplies GENERAL DESCRIPTION The ADP5301 is a high efficiency, ultralow quiescent current step-down regulator that draws only a 180 nA quiescent current to regulate the output at no load. The ADP5301 runs from an input startup voltage range of 2.15 V to 6.50 V, allowing the use of multiple alkaline/NiMH, Li-Ion cells, or other power sources. The output voltage is selectable from 0.8 V to 5.0 V by an external VID resistor and factory fuse. The total solution requires only four tiny external components. The ADP5301 can operate between hysteresis mode and PWM mode via the SYNC/MODE pin. The regulator in hysteresis mode achieves excellent efficiency at a power of less than 1 mW and provides up to 50 mA of output current. The regulator in PWM mode produces a lower output ripple and supplies up to 500 mA of output current. The flexible configuration capability during operation of the device enables very efficient power management to meet both the longest battery life and low system noise requirements. Rev. C The ADP5301 contains a VOUTOK flag, which monitors the output voltage and runs at a 2 MHz switching frequency in PWM mode. SYNC/MODE can synchronize to an external clock from 1.5 MHz to 2.5 MHz. Other key features in the ADP5301 include separate enabling, quick output discharge (QOD), and safety features such as overcurrent protection (OCP), thermal shutdown (TSD), and input undervoltage lockout (UVLO). The ADP5301 is available in a 9-ball, 1.65 mm x 1.87 mm WLCSP rated for a -40C to +125C junction temperature range. Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 (c)2015-2019 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com ADP5301 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Short-Circuit Protection............................................................ 15 Applications ....................................................................................... 1 Soft Start ...................................................................................... 15 Typical Application Circuit ............................................................. 1 Startup with a Precharged Output ........................................... 15 General Description ......................................................................... 1 100% Duty Cycle Operation ..................................................... 15 Revision History ............................................................................... 2 Active Discharge ......................................................................... 15 Functional Block Diagram .............................................................. 3 VOUTOK Function ................................................................... 15 Specifications..................................................................................... 4 Thermal Shutdown .................................................................... 15 Absolute Maximum Ratings ............................................................ 6 Applications Information .............................................................. 16 Thermal Resistance ...................................................................... 6 External Component Selection ................................................ 16 ESD Caution .................................................................................. 6 Selecting the Inductor ................................................................ 16 Pin Configuration and Function Descriptions ............................. 7 Output Capacitor........................................................................ 16 Typical Performance Characteristics ............................................. 8 Input Capacitor ........................................................................... 17 Theory of Operation ...................................................................... 14 Efficiency ..................................................................................... 17 Buck Regulator Operation Modes............................................ 14 Printed Circuit Board (PCB) Layout Recommendations ..... 18 Oscillator and Synchronization ................................................ 14 Typical Application Circuits ......................................................... 19 Adjustable and Fixed Output Voltages .................................... 14 Factory Programmable Options ................................................... 20 Undervoltage Lockout (UVLO) ............................................... 15 Outline Dimensions ....................................................................... 21 Enable/Disable ............................................................................ 15 Ordering Guide .......................................................................... 21 Current Limit .............................................................................. 15 REVISION HISTORY 7/2019--Rev. B to Rev. C Changes to Adjustable and Fixed Output Voltages Section ...... 15 Changes to Table 8, Table 9, and Table 10 ................................... 20 Changes to Ordering Guide .......................................................... 21 Updated Outline Dimensions ....................................................... 21 6/2016--Rev. A to Rev. B Changes to Features Section and General Description Section....... 1 Change to SYNC Clock Range Parameter, Table 1 ...................... 4 Change to Table 4 ..............................................................................7 Change to Oscillator and Synchronization Section ................... 14 Changes to Table 8.......................................................................... 20 12/2015--Rev. 0 to Rev. A Changes to Ordering Guide .......................................................... 21 6/2015--Revision 0: Initial Version Rev. C | Page 2 of 21 Data Sheet ADP5301 FUNCTIONAL BLOCK DIAGRAM VOUTOK PVIN PVIN 90% 87% DRIVER ILIM_PWM FB SW ILIM_HYS -0.6A(PWM) 0A(HYS) CONTROL LOGIC PWM PVIN SLOPE COMPENSATION DRIVER PGND STANDBY 0.808V 0.8V FB INTERNAL FEEDBACK RESISTOR DIVIDER 0.8V V TO I VID MODE 1.2V 0.4V SOFT START EN PVIN UVLO AGND BAND GAP BIAS AND HOUSEKEEPING 2.06V 2.00V SYNC/ MODE SYNC KEEP ALIVE BLOCK MODE Figure 2. Rev. C | Page 3 of 21 2MHz OSC 13169-002 1.2V 0.4V ADP5301 Data Sheet SPECIFICATIONS VIN = 3.6 V, VOUT = 2.5 V, TJ = -40C to +125C for minimum and maximum specifications, and TA = 25C for typical specifications, unless otherwise noted. Table 1. Parameter INPUT SUPPLY VOLTAGE RANGE SHUTDOWN CURRENT Symbol VIN ISHUTDOWN QUIESCENT CURRENT Operating Quiescent Current in Hysteresis Mode Operating Quiescent Current in PWM Mode UNDERVOLTAGE LOCKOUT UVLO Threshold Rising Falling OSCILLATOR CIRCUIT Switching Frequency in PWM Mode FB Threshold of Frequency Fold SYNCHRONIZATION THRESHOLD SYNC Clock Range SYNC High Level Threshold SYNC Low Level Threshold SYNC Duty Cycle Range SYNC/MODE Leakage Current MODE TRANSITION Transition Delay from Hysteresis Mode to PWM Mode EN PIN Input Voltage Threshold High Low Input Leakage Current FB PIN Output Options by VID Resistor PWM Mode Fixed VID Code Voltage Accuracy Adjustable VID Code Voltage Accuracy Hysteresis Mode Fixed VID Code Threshold Accuracy from Active Mode to Standby Mode Adjustable VID Code Threshold Accuracy from Active Mode to Standby Mode Hysteresis of Threshold Accuracy from Active Mode to Standby Mode Feedback Bias Current 18 18 Max 6.50 40 130 Unit V nA nA IQ_HYS 180 180 570 260 350 1400 nA nA nA IQ_PWM UVLO 425 630 A 2.06 2.00 2.14 V V 2.0 0.3 2.3 MHz V 2.5 MHz V V ns VUVLO_RISING VUVLO_FALLING Min 2.15 1.90 fSW VOSC_FOLD 1.7 SYNCCLOCK SYNCHIGH SYNCLOW SYNCDUTY 1.5 1.2 Typ 100 ISYNC_LEAKAGE 50 tHYS_TO_PWM 20 VIH VIL IEN_LEAKAGE 1.2 VOUT_OPT 0.4 1/fSW - 150 150 Test Conditions/Comments VEN = 0 V, -40C TJ +85C VEN = 0 V, -40C TJ +125C -40C TJ +85C -40C TJ +125C 100% duty cycle operation, VIN = 3.0 V, VOUT set to 3.3 V nA VSYNC/MODE = 3.6 V Clock cycles SYNC/MODE goes logic high from logic low 0.4 25 V V nA 0.8 5.0 V 0.8 V to 5.0 V in various factory options VFB_PWM_FIX -0.6 +0.6 % VFB_PWM_ADJ -1.2 -1.5 +1.2 +1.5 % % TJ = 25C, output voltage setting via factory fuse -40C TJ +125C Output voltage setting via VID resistor VFB_HYS_FIX -0.75 +0.75 % TJ = 25C VFB_HYS_ADJ -2.5 -3 +2.5 +3 % % -40C TJ +125C -40C TJ +125C VFB_HYS (HYS) 1 IFB 66 25 Rev. C | Page 4 of 21 % 95 45 nA nA Output Option 0, VOUT = 2.5 V Output Option 1, VOUT = 1.3 V Data Sheet Parameter SW PIN High-Side Power FET On Resistance Low-Side Power FET On Resistance Current-Limit in PWM Mode Peak Current in Hysteresis Mode Minimum On Time VOUTOK PIN Monitor Threshold Monitor Hysteresis Monitor Rising Delay Monitor Falling Delay Leakage Current Output Low Voltage SOFT START Default Soft Start Time Start-Up Delay COUT DISCHARGE SWITCH ON RESISTANCE THERMAL SHUTDOWN Threshold Hysteresis ADP5301 Symbol RDS (ON) H RDS (ON) L ILIM_PWM ILIM_HYS tMIN_ON VOUTOK (RISE) VOUTOK (HYS) tVOUTOK_RISE tVOUTOK_FALL IVOUTOK_LEAKAGE VOUTOK_LOW Min Typ Max Unit Test Conditions/Comments 800 324 196 1000 265 40 470 320 1200 m m mA mA ns Pin to pin measurement Pin to pin measurement SYNC/MODE = high SYNC/MODE = low 90 3 40 10 0.1 50 93 87 70 1 80 % % s s A mV tSS tSTART_DELAY RDIS 350 2 290 s ms TSHDN THYS 142 127 C C Rev. C | Page 5 of 21 IVOUTOK = 100 A Factory trim, 1 bit (350 s and 2800 s) Delay from the EN pin being pulled high ADP5301 Data Sheet ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Table 2. Parameter PVIN to PGND SW to PGND FB to AGND VID to AGND EN to AGND VOUTOK to AGND SYNC/MODE to AGND PGND to AGND Storage Temperate Range Operational Junction Temperature Range Rating -0.3 V to +7 V -0.3 V to PVIN + 0.3 V -0.3 V to +7 V -0.3 V to +7 V -0.3 V to +7 V -0.3 V to +7 V -0.3 V to +7 V -0.3 V to +0.3 V -65C to +150C -40C to +125C JA is specified for the worst case conditions, that is, a device soldered in a circuit board for surface-mount packages. Table 3. Thermal Resistance Package Type 9-Ball WLCSP ESD CAUTION Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability. Rev. C | Page 6 of 21 JA 132 Unit C/W Data Sheet ADP5301 A1 A2 A3 SW PVIN EN ADP5301 B1 B2 B3 PGND AGND SYNC/ MODE C1 C2 C3 VOUTOK FB VID 13169-003 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 3. Pin Configuration (Top View) Table 4. Pin Function Descriptions Pin No. A1 A2 A3 B1 B2 B3 Mnemonic SW PVIN EN PGND AGND SYNC/MODE C1 C2 C3 VOUTOK FB VID Description Switching Node Output for the Regulator. Power Input for the Regulator. Enable Input for the Regulator. Set this pin to logic low to disable the regulator. Power Ground. Analog Ground. Synchronization Input Pin (SYNC). To synchronize the switching frequency of the device to an external clock, connect this pin to an external clock with a frequency from 1.5 MHz to 2.5 MHz. PWM or Hysteresis Mode Selection Pin (MODE). When this pin is logic high, the regulator operates in PWM mode. When this pin is logic low, the regulator operates in hysteresis mode. Output Power-Good Signal. This open-drain output is the power-good signal for the output voltage. Feedback Sensing Input for the Regulator. Voltage Configuration Pin. Connect an external resistor (RVID) from this pin to ground to configure the output voltage of the regulator (see Table 5). Rev. C | Page 7 of 21 ADP5301 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS VIN = 3.6 V, VOUT = 2.5 V, L = 2.2 H, CIN = COUT = 10 F, fSW = 2 MHz, TA = 25C, unless otherwise noted. 100 100 90 90 60 VIN = 2.5V VIN = 3.0V VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 50 40 0.010 0.100 1.000 LOAD CURRENT (mA) 10.000 40 0.001 0.010 0.100 1.000 LOAD CURRENT (mA) 10.000 Figure 7. Hysteresis Efficiency vs. Load Current, VOUT = 1.5 V 100 100 90 90 EFFICIENCY (%) 80 70 VIN = 2.5V VIN = 3.0V VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 60 50 0.010 0.100 1.000 LOAD CURRENT (mA) 10.000 80 70 VIN = 3.0V VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 60 13169-005 EFFICIENCY (%) VIN = 2.5V VIN = 3.0V VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 60 50 Figure 4. Hysteresis Efficiency vs. Load Current, VOUT = 1.2 V 40 0.001 70 50 0.001 Figure 5. Hysteresis Efficiency vs. Load Current, VOUT = 1.8 V 0.010 0.100 1.000 LOAD CURRENT (mA) 13169-008 30 0.001 80 13169-007 EFFICIENCY (%) 70 13169-004 EFFICIENCY (%) 80 10.000 Figure 8. Hysteresis Efficiency vs. Load Current, VOUT = 2.5 V 100 100 90 90 80 60 50 40 VIN = 2.5V VIN = 3.0V VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 30 VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 60 50 0.001 0.010 0.100 1.000 LOAD CURRENT (mA) 10.000 20 10 0 0 Figure 6. Hysteresis Efficiency vs. Load Current, VOUT = 3.3 V 100 200 300 LOAD CURRENT (mA) 400 Figure 9. PWM Efficiency vs. Load Current, VOUT = 1.2 V Rev. C | Page 8 of 21 500 13169-009 EFFICIENCY (%) 70 13169-006 EFFICIENCY (%) 70 80 ADP5301 100 100 90 80 70 70 60 50 40 VIN = 2.5V VIN = 3.0V VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 10 20 10 0 0 100 200 300 LOAD CURRENT (mA) 400 500 0 90 80 80 70 70 EFFICIENCY (%) 90 60 50 40 100 200 300 LOAD CURRENT (mA) 400 60 50 40 10 500 0 200 300 LOAD CURRENT (mA) 400 6.5 350 QUIESCENT CURRENT (nA) -40C +25C +85C +125C 100 80 60 40 300 -40C +25C +85C +125C 250 200 150 20 0 2.3 2.9 3.5 4.1 4.7 VIN (V) 5.3 5.9 6.5 13169-012 SHUTDOWN CURRENT (nA) 100 Figure 14. PWM Efficiency vs. Load Current, VOUT = 3.3 V 160 120 500 0 Figure 11. PWM Efficiency vs. Load Current, VOUT = 2.5 V 140 VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 20 0 0 500 30 VIN = 3.0V VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 13169-011 EFFICIENCY (%) 100 10 400 Figure 13. PWM Efficiency vs. Load Current, VOUT = 1.8 V 100 20 300 200 LOAD CURRENT (mA) 100 0 Figure 10. PWM Efficiency vs. Load Current, VOUT = 1.5 V 30 VIN = 2.5V VIN = 3.0V VIN = 3.6V VIN = 4.2V VIN = 5.0V VIN = 6.0V 13169-014 20 40 30 13169-015 30 60 50 13169-013 EFFICIENCY (%) 90 80 13169-010 EFFICIENCY (%) Data Sheet 100 2.3 Figure 12. Shutdown Current vs. VIN, EN = Low 2.9 3.5 4.7 4.1 VIN (V) 5.3 5.9 Figure 15. Hysteresis Quiescent Current vs. VIN, SYNC/MODE = Low Rev. C | Page 9 of 21 ADP5301 Data Sheet 810 801 808 FEEDBACK VOLTAGE (mV) FEEDBACK VOLTAGE (mV) ACTIVE TO STANDBY 800 799 798 806 804 STANDBY TO ACTIVE 802 800 798 796 797 -40 +25 +85 TEMPERATURE (C) +125 792 Figure 19. Feedback Voltage vs. Temperature, Hysteresis Mode 400 700 -40C +25C +125C -40C +25C +125C 350 LOW-SIDE RDS (ON) L (m) 500 400 300 200 300 250 200 3.5 4.1 4.7 VIN (V) 5.3 5.9 6.5 100 2.3 2.9 Figure 17. High-Side RDS (ON) H vs. VIN 3.5 4.1 4.7 VIN (V) 5.3 5.9 6.5 13169-020 2.9 13169-017 150 5.9 6.5 13169-021 HIGH-SIDE RDS (ON) H (m) 600 Figure 20. Low-Side RDS (ON) L vs. VIN 1200 1090 1150 PEAK CURRENT LIMIT (mA) 1040 990 940 1100 -40C +25C +125C 1050 1000 950 900 890 850 840 -40 +25 +85 TEMPERATURE (C) +125 13169-018 PEAK CURRENT LIMIT (mA) +125 +85 +25 TEMPERATURE (C) -40 Figure 16. Feedback Voltage vs. Temperature, PWM Mode 100 2.3 13169-019 13169-016 794 Figure 18. Peak Current Limit vs. Temperature 800 2.3 2.9 3.5 4.1 4.7 VIN (V) 5.3 Figure 21. Peak Current Limit vs. VIN Rev. C | Page 10 of 21 Data Sheet ADP5301 2.10 2.3 SWITCHING FREQUENCY (kHz) 2.08 2.04 2.02 FALLING 2.00 2.1 2.0 1.9 1.8 1.96 -40 +25 +85 TEMPERATURE (C) +125 1.7 2.3 2.9 3.5 4.1 4.7 VIN (V) 5.3 5.9 6.5 Figure 25. Switching Frequency vs. VIN Figure 22. UVLO Threshold, Rising and Falling vs. Temperature 1 VOUT VOUT (AC) 1 SW IL 2 4 IL 4 2 M 200s A CH4 T 39.60% 140mA B CH1 10.0mV Figure 23. Steady Waveform of Hysteresis Mode, ILOAD = 1 mA (IL is the Inductor Current) W CH2 2.00V M 400ns A CH2 CH4 200mA BW T 90.60% 2.72V 13169-026 CH2 2.00V CH4 500mA 13169-023 SW CH1 100mV Figure 26. Steady Waveform of PWM Mode, ILOAD = 300 mA VIN VIN VOUT 3 VOUT 1 1 IL IL 4 4 SW SW 2 CH1 1.00V CH3 2.00V B W B W CH2 5.00V M 200s A CH1 CH4 500mA BW T 50.60% 1.22V CH1 500mV CH3 2.00V Figure 24. Soft Start, ILOAD = 300 mA B B W W CH2 5.00V M 100s A CH1 CH4 500mA BW T 40.00% Figure 27. Soft Start with Precharge Function Rev. C | Page 11 of 21 1.05V 13169-027 2 13169-025 13169-022 1.98 13169-024 UVLO THRESHOLD (V) RISING 2.06 -40C +25C +125C 2.2 ADP5301 Data Sheet VOUT (AC) 1 1 VOUT (AC) IOUT IOUT CH1 50.0mV B W M 200s A CH4 CH4 50.0mA BW T 20.80% 111mA CH1 50.0mV Figure 28. Load Transient of Hysteresis Mode, ILOAD from 0 mA to 50 mA B W CH4 200mA B W M 200s A CH4 T 20.40% 308mA 13169-031 4 13169-028 4 Figure 31. Load Transient of PWM Mode, ILOAD from 125 mA to 375 mA 1 1 VOUT (AC) VOUT (AC) VIN VIN IL 3 4 IL 4 SW 2 2 B B W W CH2 5.00V CH4 500mA B W M 2.00ms A CH3 T 30.00% 4.72V B CH1 10.0mV CH3 2.00V Figure 29. Line Transient of Hysteresis Mode, ILOAD = 10 A, VIN from 2.5 V to 6 V W B W CH2 5.00V CH4 500mA B W M 2.00ms A CH3 T 30.20% 4.28V 13169-032 CH1 50.0mV CH3 2.00V 13169-029 SW Figure 32. Line Transient of PWM Mode, ILOAD = 500 mA, VIN from 2.5 V to 6 V VIN VOUT VOUT 1 VOUTOK 3 1 IL SW 4 B B W W CH4 200mA B W M 10.0ms A CH3 T 40.20% 4.80V CH1 1.00V CH3 1.00V Figure 30. Input Voltage Ramp Up and Ramp Down in Hysteresis Mode Rev. C | Page 12 of 21 B W B W CH2 2.00V B W M 200s A CH1 T 40.00% Figure 33. VOUTOK Function 1.32V 13169-033 CH1 1.00V CH3 1.00V 13169-030 2 Data Sheet ADP5301 VOUT VOUT 1 1 IL IL 4 4 SW SW W CH2 2.00V CH4 500mA M 10.0s A CH1 T 40.20% 1.44V B CH1 2.00V W Figure 34. Output Short Protection CH2 2.00V CH4 500mA M 1.00ms A CH1 T 40.20% 1.44V 13169-036 B 13169-034 CH1 2.00V 1.64V 13169-037 2 2 Figure 36. Output Short Recovery EN 1 SYNC/ MODE 3 VOUT SW 1 2 2 CH1 2.00V B W CH2 2.00V M 400ns A CH2 T 50.00% 1.40V 13169-035 SW CH1 1.00V CH3 2.00V Figure 35. Synchronized to 2.5 MHz B W B W CH2 2.00V B W M 4.00ms A CH3 T 40.00% Figure 37. Quick Output Discharge Function Rev. C | Page 13 of 21 ADP5301 Data Sheet THEORY OF OPERATION The ADP5301 is a high efficiency, ultralow quiescent current step-down regulator in a 9-ball WLCSP to meet demanding performance and board space requirements. The device enables direct connection to the wide input voltage range of 2.15 V to 6.50 V, allowing the use of multiple alkaline/NiMH or Li-Ion cells and other power sources. BUCK REGULATOR OPERATION MODES The user can alternate between hysteresis mode and PWM mode during operation. The flexible configuration capability during operation of the device enables efficient power management to meet high efficiency and low output ripple requirements when the system switches between active mode and standby mode. OSCILLATOR AND SYNCHRONIZATION The ADP5301 operates at a 2 MHz switching frequency typical in PWM operation mode. PWM Mode In PWM mode, the buck regulator in the ADP5301 operates at a fixed frequency that is set by an internal oscillator. At the start of each oscillator cycle, the high-side MOSFET switch turns on and sends a positive voltage across the inductor. The inductor current increases until the current sense signal exceeds the peak inductor current threshold, which turns off the high-side MOSFET switch. This threshold is set by the error amplifier output. During the high-side MOSFET off time, the inductor current decreases through the low-side MOSFET until the next oscillator clock pulse starts a new cycle. Hysteresis Mode In hysteresis mode, the buck regulator in the ADP5301 charges the output voltage slightly higher than its nominal output voltage with PWM pulses by regulating the constant peak inductor current. When the output voltage increases until the output sense signal exceeds the hysteresis upper threshold, the regulator enters standby mode. In standby mode, the high-side and low-side MOSFETs and a majority of the circuitry are disabled to allow a low quiescent current as well as high efficiency performance. During standby mode, the output capacitor supplies energy into the load and the output voltage decreases until it falls below the hysteresis comparator lower threshold. The buck regulator wakes up and generates the PWM pulses to charge the output again. Because the output voltage occasionally enters standby mode and then recovers, the output voltage ripple in hysteresis mode is larger than the ripple in PWM mode. Mode Selection The ADP5301 includes the SYNC/MODE pin to allow flexible configuration in hysteresis mode or PWM mode. When a logic high level is applied to the SYNC/MODE pin, the buck regulator is forced to operate in PWM mode. In PWM mode, the regulator can supply up to 500 mA of output current. The regulator can provide lower output ripple and output noise in PWM mode, which is useful for noise sensitive applications. When a logic low level is applied to the SYNC/MODE pin, the buck regulator is forced to operate in hysteresis mode. In hysteresis mode, the regulator draws only 180 nA of quiescent current typical to regulate the output under zero load, which allows the regulator to act as a keep-alive power supply in a battery-powered system. In hysteresis mode, the regulator supplies up to 50 mA of output current with a relatively large output ripple compared to PWM mode. The switching frequency of the ADP5301 can be synchronized to an external clock with a frequency range from 1.5 MHz to 2.5 MHz. The ADP5301 automatically detects the presence of an external clock applied to the SYNC/MODE pin, and the switching frequency transitions to the frequency of the external clock. When the external clock signal stops, the device automatically switches back to the internal clock. ADJUSTABLE AND FIXED OUTPUT VOLTAGES The ADP5301 provides adjustable output voltage settings by connecting one resistor through the VID pin to AGND. The VID detection circuitry works in the start-up period, and the voltage ID code is sampled and held into the internal register and does not change until the next power recycle. Furthermore, the ADP5301 provides a fixed output voltage programmed via the factory fuse. In this condition, connect the VID pin to the PVIN pin. For the output voltage settings, the feedback resistor divider is built into the ADP5301, and the feedback pin (FB) must be tied directly to the output. An ultralow power voltage reference and an integrated high impedance (50 M typical) feedback divider network contribute to the low quiescent current. Table 5 lists the output voltage options by the VID pin configurations. Table 5. Output Voltage (VOUT) Options Using the VID Pin VID Configuration Short to Ground Short to PVIN RVID = 499 k RVID = 316 k RVID = 226 k RVID = 174 k RVID = 127 k RVID = 97.6 k RVID = 76.8 k RVID = 56.2 k RVID = 43 k RVID = 32.4 k RVID = 25.5 k RVID = 19.6 k RVID = 15 k RVID = 11.8 k Rev. C | Page 14 of 21 VOUT (V) Factory Option 0 Factory Option 1 3.0 3.1 2.5 1.3 3.6 5.0 3.3 4.5 2.9 4.2 2.8 3.9 2.7 3.4 2.6 3.2 2.4 1.9 2.3 1.7 2.2 1.6 2.1 1.4 2.0 1.1 1.8 1.0 1.5 0.9 1.2 0.8 Data Sheet ADP5301 Any of the individual VID settings are available as internally fixed options. Contact an Analog Devices, Inc., sales representative for more information on generating new models. UNDERVOLTAGE LOCKOUT (UVLO) The undervoltage lockout circuitry monitors the input voltage level on the PVIN pin. If input voltage falls below 2.00 V (typical), the regulator turns off. After the input voltage rises above 2.06 V (typical), the soft start period is initiated, and the regulator is enabled when the EN pin is high. ENABLE/DISABLE The ADP5301 includes a separate enable pin (EN). A logic high in the EN pin starts the regulator. Due to the low quiescent current design, it is typical for the regulator to start switching after a delay of a few milliseconds from the EN pin being pulled high. A logic low on the EN pin immediately disables the regulator and brings the regulator into extremely low current consumption. CURRENT LIMIT The buck regulator in the ADP5301 has protection circuitry that limits the direction and the amount of current to a certain level that flows through the high-side MOSFET and the low-side MOSFET in cycle-by-cycle mode. The positive current limit on the high-side MOSFET limits the amount of current that can flow from the input to the output. The negative current limit on the low-side MOSFET prevents the inductor current from reversing direction and flowing out of the load. SHORT-CIRCUIT PROTECTION The buck regulator in ADP5301 includes frequency foldback to prevent current runaway on a hard short. When the output voltage at the FB pin falls below 0.3 V typical, indicating the possibility of a hard short at the output, the switching frequency (in PWM mode) is reduced to one-fourth of the internal oscillator frequency. The reduction in the switching frequency allows more time for the inductor to discharge, preventing a runaway of output current. SOFT START The ADP5301 has an internal soft start function that ramps up the output voltage in a controlled manner upon startup, thereby limiting the inrush current. This feature prevents possible input voltage drops when a battery or a high impedance power source is connected to the input of the device. The default typical soft start time is 350 s for the regulator. A different soft start time (2800 s) can be programmed for ADP5301 by the factory fuse. STARTUP WITH A PRECHARGED OUTPUT The buck regulator in the ADP5301 includes a precharged start-up feature to protect the low-side MOSFET from damage during startup. If the output voltage is precharged before the regulator turns on, the regulator prevents reverse inductor current--which discharges the output capacitor--until the internal soft start reference voltage exceeds the precharged voltage on the feedback pin. 100% DUTY CYCLE OPERATION When the input voltage approaches the output voltage, the ADP5301 stops switching and enters 100% duty cycle operation. It connects the output via the inductor and the internal high-side power switch to the input. When the input voltage is charged again and the required duty cycle falls to 95% typical, the buck immediately restarts switching and regulation without allowing overshoot on the output voltage. In hysteresis mode, the ADP5301 draws an ultralow quiescent current of only 570 nA typical during 100% duty cycle operation ACTIVE DISCHARGE The ADP5301 integrates an optional, factory programmable discharge switch from the switching node to ground. This switch turns on when its associated regulator is disabled, which helps discharge the output capacitor quickly. The typical value of the discharge switch is 290 for the regulator. By default, the discharge function is not enabled. The active discharge function can be enabled by the factory fuse. VOUTOK FUNCTION The ADP5301 includes an open-drain power-good output (VOUTOK pin) that is active high when the buck regulator is operating normally. By default, the VOUTOK pin monitors the output voltage. A logic high on the VOUTOK pin indicates that the regulated output voltage of the buck regulator is above 90% (typical) of its nominal output. When the regulated output voltage of the buck regulator falls below 87% (typical) of its nominal output for a delay time greater than approximately 10 s, the VOUTOK pin goes low. THERMAL SHUTDOWN If the ADP5301 junction temperature exceeds 142C, the thermal shutdown circuit turns off the IC except for the internal linear regulator. Extreme junction temperatures can be the result of high current operation, poor circuit board design, or high ambient temperature. A 15C hysteresis is included so that the ADP5301 does not return to operation after thermal shutdown until the junction temperature falls below 127C. When the device exits thermal shutdown, a soft start is initiated for the buck regulator. Rev. C | Page 15 of 21 ADP5301 Data Sheet APPLICATIONS INFORMATION This section describes the external components selection for the ADP5301. A typical application circuit is shown in Figure 38. VIN = 2.15V TO 6.50V 2.2H VOUT = 1.8V A minimum requirement of the dc current rating of the inductor is for it to be equal to the maximum load current plus half of the inductor current ripple (IL), as shown by the following equations: SW PVIN 10F MLCC ADP5301 10F MLCC (9-BALL WLCSP) EN I L = VOUT PGND R1 1M SYNC/ MODE FB I I PK = I LOAD ( MAX ) + L 2 VOUTOK Use the inductor series from different vendors shown in Table 6. VID RVID 20k 13169-038 AGND VOUT 1 - VIN + L x f SW Figure 38. Typical Application Circuit EXTERNAL COMPONENT SELECTION The ADP5301 is optimized for operation with a 2.2 H inductor and 10 F output capacitors for various output voltages using the closed-loop compensation and adaptive slope compensation circuits. The selection of components depends on the efficiency, the load current transient, and other application requirements. The trade-offs among performance parameters, such as efficiency and transient response, are made by varying the choice of external components. SELECTING THE INDUCTOR The high switching frequency of the ADP5301 allows the use of small surface-mount power inductors. The dc resistance (DCR) value of the selected inductor affects efficiency. In addition, it is recommended to select a multilayer inductor rather than a magnetic iron inductor because the high switching frequency increases the core temperature rise and enlarges the core loss. OUTPUT CAPACITOR Output capacitance is required to minimize the voltage overshoot, the voltage undershoot, and the ripple voltage present on the output. Capacitors with low equivalent series resistance (ESR) values produce the lowest output ripple. Furthermore, use capacitors such as X5R and X7R dielectric capacitors. Do not use Y5V and Z5U capacitors, which are unsuitable choices due to their large capacitance variation over temperature and their dc bias voltage changes. Because ESR is important, select the capacitor using the following equation: ESRCOUT VRIPPLE I L where: ESRCOUT is the ESR of the chosen capacitor. VRIPPLE is the peak-to-peak output voltage ripple. Increasing the output capacitor value has no effect on stability and may reduce output ripple and enhance load transient response. When choosing the output capacitor value, it is important to account for the loss of capacitance due to output voltage dc bias. Use the capacitor series from different vendors shown in Table 7. Table 6. Recommended Inductors Vendor TDK Wurth Coilcraft 1 Model MLP2016V2R2MT0S1 74479889222 LPS3314-222MR Inductance (H) 2.2 2.2 2.2 Dimensions (mm) 2.0 x 1.6 x 0.85 2.5 x 2.0 x 1.2 3.3 x 3.3 x 1.3 DCR (m) 280 250 100 ISAT 1 (A) 1.0 1.7 1.5 ISAT is the dc current at which the inductance drops 30% (typical) from its value without current. Table 7. Input and Output Capacitors Vendor Murata Murata Murata Model GRM188D71A106MA73 GRM21BR71A106KE51 GRM31CR71A106KA01 Capacitance (F) 10 10 10 Rev. C | Page 16 of 21 Size 0603 0805 1206 Data Sheet ADP5301 INPUT CAPACITOR An input capacitor is required to reduce the input voltage ripple, input ripple current, and source impedance. Place the input capacitor as close as possible to the PVIN pin. A low ESR X7R or X5R capacitor is highly recommended to minimize the input voltage ripple. Use the following equation to determine the rms input current: I RMS I LOAD ( MAX ) VOUT (VIN - VOUT ) VIN For most applications, a 10 F capacitor is sufficient. The input capacitor can be increased without any limit for better input voltage filtering. EFFICIENCY Efficiency is the ratio of output power to input power. The high efficiency of the ADP5301 has two distinct advantages. First, only a small amount of power is lost in the dc-to-dc converter package, which in turn reduces thermal constraints. Second, the high efficiency delivers the maximum output power for the given input power, thereby extending battery life in portable applications. Power Switch Conduction Losses Power switch dc conduction losses are caused by the flow of output current through the high-side P-channel power switch and the low-side N-channel synchronous rectifier, which have internal resistances (RDS (ON)) associated with them. The amount of power loss is approximated by To estimate the total amount of power lost in the inductor, use the following equation: PL = DCR x IOUT2 + Core Losses Driver Losses Driver losses are associated with the current drawn by the driver to turn on and turn off the power devices at the switching frequency. Each time a power device gate is turned on and turned off, the driver transfers a charge from the input supply to the gate, and then from the gate to ground. Estimate driver losses using the following equation: PDRIVER = (CGATE_H + CGATE_L) x VIN2 x fSW where: CGATE_H is the gate capacitance of the internal high-side switch. CGATE_L is the gate capacitance of the internal low-side switch. fSW is the switching frequency in PWM mode. The typical values for the gate capacitances are 69 pF for CGATE_H and 31 pF for CGATE_L. Transition Losses Transition losses occur because the P-channel switch cannot turn on or turn off instantaneously. In the middle of a switch node transition, the power switch provides all of the inductor current. The source to drain voltage of the power switch is half of the input voltage, resulting in power loss. Transition losses increase with both load current and input voltage and occur twice for each switching cycle. Use the following equation to estimate transition losses: PSW_COND = (RDS (ON) H x D + RDS (ON) L x (1 - D)) x IOUT2 PTRAN = VIN/2 x IOUT x (tR + tF) x fSW where: where: tR is the rise time of the SW node. tF is the fall time of the SW node. V D = OUT VIN The typical value for the rise and fall times, tR and tF, is 2 ns. The internal resistance of the power switches increases with temperature and with the input voltage decrease. Inductor Losses Inductor conduction losses are caused by the flow of current through the inductor, which has an internal DCR associated with it. Larger size inductors have smaller DCR, which can decrease inductor conduction losses. Inductor core losses relate to the magnetic permeability of the core material. Because the ADP5301 is a high switching frequency dc-to-dc regulator, shielded ferrite core material is recommended because of its low core losses and low electromagnetic interference (EMI). Rev. C | Page 17 of 21 ADP5301 Data Sheet PRINTED CIRCUIT BOARD (PCB) LAYOUT RECOMMENDATIONS VOUT VIN L1 - 2.2H 0603 A2 A3 PVIN EN ADP5301 B1 B2 B3 PGND AGND SYNC/ MODE C1 C2 C3 VOUTOK FB VID 10F 10V/XR5 0603 3.00 GND 100k 0201 3.60 Figure 39. Typical PCB Layout Rev. C | Page 18 of 21 13169-039 10F 6.3V/XR5 0603 A1 SW Data Sheet ADP5301 TYPICAL APPLICATION CIRCUITS The ADP5301 can be used as a keep-alive, ultralow step-down power regulator to extend the battery life (see Figure 40) and as a batterypowered equipment or wireless sensor network controlled by a microcontroller or a processor (see Figure 41). 2.2H VIN = 3.0V TO 4.2V 10F Li-Ion BATTERY ADP5301 RVID 20k 1% VOUT = 1.8V SW PVIN 10F EN PGND VID FB VOUTOK SYNC/MODE 13169-040 AGND Figure 40. Typical ADP5301 Application with Li-Ion Battery 2.2H VIN = 2.0V TO 3.0V 10F ADP5301 RVID 20k 1% VOUT = 1.8V SW PVIN ADC/RF/AFE 10F EN PGND VID FB R1 1M VOUTOK MCU (ALWAYS ON) SYNC/MODE AGND 13169-041 TWO ALKALINE OR NiMH BATTERIES Figure 41. Typical ADP5301 Application with Two Alkaline/NiMH Batteries Rev. C | Page 19 of 21 ADP5301 Data Sheet FACTORY PROGRAMMABLE OPTIONS To order a device with options other than the default options, contact your local Analog Devices sales or distribution representative. Table 8. Output Voltage VID Setting Options Option Option 0 Option 1 Option 2 Description VID resistor to set the output voltage as follows: 1.2 V, 1.5 V, 1.8 V, 2.0 V, 2.1 V, 2.2 V, 2.3 V, 2.4 V, 2.5 V, 2.6 V, 2.7 V, 2.8 V. 2.9 V, 3.0 V, 3.3 V, or 3.6 V (ADP5301ACBZ-1-R7 and ADP5301ACBZ-2-R7 default) VID resistor to set the output voltage as follows: 0.8 V, 0.9 V, 1.0 V, 1.1 V, 1.3 V, 1.4 V, 1.6 V, 1.7 V, 1.9 V, 3.1 V, 3.2 V, 3.4 V, 3.9 V, 4.2 V, 4.5 V, or 5.0 V (ADP5301ACBZ-3-R7 default) 3.3 V fixed output voltage without VID setting: ADP5301ACBZ-4-R7 Table 9. Output Discharge Functionality Options Option Option 0 Option 1 Description Output discharge function disabled for buck regulator (ADP5301ACBZ-2-R7 and ADP5301ACBZ-4-R7 default) Output discharge function enabled for buck regulator (ADP5301ACBZ-1-R7 and ADP5301ACBZ-3-R7 default) Table 10. Soft Start Time Options Option Option 0 Option 1 Description 350 s (ADP5301ACBZ-1-R7, ADP5301ACBZ-2-R7, and ADP5301ACBZ-3-R7 default) 2800 s (ADP5301ACBZ-4-R7 default) Rev. C | Page 20 of 21 Data Sheet ADP5301 OUTLINE DIMENSIONS 1.690 1.650 1.610 0.455 0.435 0.415 3 2 1 A BALL A1 IDENTIFIER 1.910 1.870 1.830 1.00 REF B C 0.50 BSC TOP VIEW BOTTOM VIEW (BALL SIDE DOWN) 0.660 0.600 0.540 0.390 0.360 0.330 END VIEW 0.345 0.325 0.305 (BALL SIDE UP) SEATING PLANE PKG-003136 0.360 0.320 0.280 0.270 0.240 0.210 05-23-2019-A COPLANARITY 0.04 Figure 42. 9-Ball Wafer Level Chip Scale Package [WLCSP] (CB-9-6) Dimensions shown in millimeters ORDERING GUIDE Model 1 ADP5301ACBZ-1-R7 ADP5301ACBZ-2-R7 ADP5301ACBZ-3-R7 ADP5301ACBZ-4-R7 ADP5301-EVALZ 1 Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package Description 9-Ball Wafer Level Chip Scale Package [WLCSP] 9-Ball Wafer Level Chip Scale Package [WLCSP] 9-Ball Wafer Level Chip Scale Package [WLCSP] 9-Ball Wafer Level Chip Scale Package [WLCSP] Evaluation Board Z = RoHS Compliant Part. (c)2015-2019 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D13169-0-7/19(C) Rev. C | Page 21 of 21 Package Option CB-9-6 CB-9-6 CB-9-6 CB-9-6