High Voltage, 1.2 MHz/600 kHz, 800 mA, Low Quiescent Current Buck Regulator Data Sheet ADP2370/ADP2371 FEATURES TYPICAL APPLICATION CIRCUIT V = 6V IN Input voltage range: 3.2 V to 15 V, output current: 800 mA C Quiescent current < 14 A in power saving mode (PSM) IN 10F >90% efficiency POWER GOOD Force PWM pin (SYNC), 600 kHz/1.2 MHz frequency pin ADP2370/ ADP2371 (FSEL) VIN PGND 1 8 Fixed outputs: 0.8 V, 1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.0 V, 3.3 V, 5 V, and adjustable option 1.2MHz V = 3.3V OUT SW FSEL 2 7 100% duty cycle capability 600kHz C OUT Initial accuracy: 1% ON 10F EN PG 3 6 OFF Low shutdown current: <1.2 A AGND (EXPOSED PAD) Quick output discharge (QOD) option SYNC FB 4 5 Synchronizable to an external clock 8-lead, 0.75 mm 3 mm 3 mm LFCSP (QFN) package Supported by ADIsimPower design tool Figure 1. APPLICATIONS Portable and battery-powered equipment Automatic meter readers (WSN) Point of sales and transaction processing instruments Medical instruments Medium format display tablets and pads GENERAL DESCRIPTION The ADP2370/ADP2371 are high efficiency, low quiescent current, A power-good output is available to indicate when the output 800 mA buck (step-down) dc-to-dc converters in small 8-lead, voltage is below 92% of its nominal value. 3 mm 3 mm LFCSP (QFN) packages. The total solution requires The ADP2371 is identical to the ADP2370 except that the only three tiny external components. ADP2371 includes the addition of an integrated switched The buck regulator uses a proprietary high speed current mode, resistor, quick output discharge function (QOD) that auto- constant frequency PWM control scheme for excellent stability matically discharges the output when the device is disabled. and transient response. The need for an external rectifier is elimi- Both devices include an internal power switch and a synchronous nated by using a high efficiency synchronous rectifier architecture. rectifier for minimal external part count and high efficiency. To ensure the longest battery life in portable applications, the The ADP2370/ADP2371 also include internal soft start and ADP2370/ADP2371 employ a power saving variable frequency internal compensation for ease of use. mode that reduces the switching frequency under light load During a logic controlled shutdown, the input is disconnected conditions. The ADP2370/ADP2371 operate from input voltages from the output and the regulator draws less than 1.2 A from of 3.2 V to 15 V allowing the use of multiple alkaline/NiMH, the input source. Other key features include undervoltage lockout lithium cells, or other standard power sources. to prevent deep battery discharge and soft start to prevent input The ADP2370/ADP2371 offer multiple options for setting the overcurrent at startup. Short-circuit protection and thermal over- load protection circuits prevent damage under adverse conditions. operational frequency. The ADP2370/ADP2371 can be synchro- nized to a 600 kHz to 1.2 MHz external clock or it can be forced The ADP2370/ADP2371 each use one 0805 capacitor, one 1206 to operate at 600 kHz or 1.2 MHz via the FSEL pin. The ADP2370/ capacitor, and one 4 mm 4 mm inductor. The total solution ADP2371 can be forced to operate in PWM mode (FPWM) when 2 size is about 53 mm resulting in a very small footprint solution noise considerations are more important than efficiency. to meet a variety of portable applications. Rev. E 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20122019 Analog Devices, Inc. All rights reserved. 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. Technical Support www.analog.com 09531-001ADP2370/ADP2371 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Undervoltage Lockout ............................................................... 22 Applications ....................................................................................... 1 Thermal Protection .................................................................... 22 Typical Application Circuit ............................................................. 1 Soft Start ...................................................................................... 22 General Description ......................................................................... 1 Current Limit .............................................................................. 22 Revision History ............................................................................... 2 100% Duty Cycle ........................................................................ 23 Specifications ..................................................................................... 3 Synchronizing ............................................................................. 23 Recommended Specifications: Capacitors ................................ 5 Power Good ................................................................................ 24 Absolute Maximum Ratings ....................................................... 6 Applications Information .............................................................. 25 Thermal Data ................................................................................ 6 ADIsimPower Design Tool ....................................................... 25 Thermal Resistance ...................................................................... 6 External Component Selection ................................................ 25 ESD Caution .................................................................................. 6 Selecting the Inductor ................................................................ 25 Pin Configuration and Function Descriptions ............................. 7 Output Capacitor ........................................................................ 25 Typical Performance Characteristics ............................................. 8 Input Capacitor ........................................................................... 25 Buck Output .................................................................................. 8 Adjustable Output Voltage Programming .............................. 25 Theory of Operation ...................................................................... 20 Efficiency ..................................................................................... 26 PWM Operation ......................................................................... 20 Recommended Buck External Components .......................... 26 PSM Operation ........................................................................... 21 Capacitor Selection .................................................................... 28 Features Descriptions ..................................................................... 22 Thermal Considerations ................................................................ 29 Precision Enable ......................................................................... 22 PCB Layout Considerations ...................................................... 30 Forced PWM or PWM/PSM Selection.................................... 22 Packaging and Ordering Information ......................................... 32 Quick Output Discharge (QOD) Function ............................. 22 Outline Dimensions ................................................................... 32 Short-Circuit Protection ............................................................ 22 Ordering Guide .......................................................................... 32 REVISION HISTORY 10/2019Rev. D to Rev. E Changes to Output Capacitor Section ......................................... 25 5/2012Rev. 0 to Rev. A Updated Outline Dimensions ....................................................... 32 Changed Voltage Range for SW to PGND and Ground Plane Change to Ordering Guide ............................................................ 32 from 0.3 V to VIN + 0.3 V to 0.7 V to VIN + 0.3 V ................ 6 Changes to Ordering Guide .......................................................... 32 2/2014Rev. C to Rev. D Change to Figure 13 ......................................................................... 9 4/2012Revision 0: Initial Version Updated Outline Dimensions ....................................................... 32 11/2012Rev. B to Rev. C Change to Figure 6 ........................................................................... 8 Changes to Ordering Guide............................................................. 32 8/2012Rev. A to Rev. B Change to Figure 62 ....................................................................... 17 Changes to Figure 63, Figure 64, Figure 65, and Figure 66 ............ 18 Rev. E Page 2 of 32