ZXSC380

ZXSC380 Single or multi cell LED driver solution

Document overview

• Manufacturer or author: Diodes Incorporated
• PDF pages: 11

Technical content

Features

• 80% efficiency  User adjustable output current  Single cell operation  Low saturation voltage switching transistor  Simple application circuit  Low external component count  SOT23 package  Available also in die form

Applications

 LED flashlights and torches  LED backlights  White LED driver Pin connections Typical application circuit VCC GND VOUT Top view VCC VOUT GND VIN GND LED1 ZXSC380 NOT RECOMMENDED FOR NEW DESIGN - USE PAM2803 NOT RECOMMENDED FOR NEW DESIGN

Supply voltage (VCC) -0.6V to 10V Output voltage (VOUT) -0.6V to 20V Supply current 20mA Output switch current 200mA Power dissipation SOT23-3 450mW Power dissipation die 1W Operating temperature range 0°C to +85°C Storage temperature range -55°C to +150°C

Electrical characteristics

Measured at Tamb = 25°C, L = 100/H9262H and VCC = 1.5V unless otherwise specified. Pin descriptions Pin descriptions

Ordering information

Parameter Conditions Limits Units Min. Typ. Max. Supply voltage operating range 0.8 6 V Minimum supply start-up voltage 0.9 1.0 V Switch current VOUT = 1.0V 65 80 95 mA Switch saturation voltage IVOUT = 50mA 0.3 0.5 V Mean LED current VLED = 3.5V 18 mA Efficiency VLED = 3.5V 75 % Operating frequency VLED = 3.5V 160 kHz Discharge pulse width 1.4 2.2 3.0 /H9262s Pin No. Name Description 1V CC Supply voltage, generally Alkaline, NiMH or NiCd single cell 2V OUT Switch output external inductor/LED

3 GND Ground

Document number: DS33616 Rev. 4 - 3 March 2024 2024 Copyright Diodes Incorporated. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGN

LED Current vs Supply Voltage for L = 100uH 0 . 511 . 522 . 53 Supply Voltage Vvcc (V) LED Current, ILed (mA) Ivcc vs Supply Voltage for L = 100uH 100 0.5 1 1.5 2 2.5 3 Supply Voltage Vvcc (V) Ivcc (mA) Efficiency vs Supply Voltgae for L = 100uH 100 0.5 1 1.5 2 2.5 3 Supply Voltage Vvcc (V) Efficiency (%) Operating Waveforms Channel 1 (lower): LED current ILed. 50mA/div. Channel 2 (upper): Voltage at Vout pin. 1V/div ZXSC380 Document number: DS33616 Rev. 4 - 3 March 2024 © 2024 Copyright Diodes Incorporated. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGN

LED Current vs Supply Voltage for L = 22, 47, 68 & 100uH Supply Voltage Vvcc (V) LED Current ILed (mA) L = 100uH L = 68uH L = 47uH L = 22uH LED Current vs Supply Voltage for L= 22, 47, 68 & 100uH 11 . 5 22 . 5 Supply Voltage Vvcc (V) LED Current ILed (mA) L = 100uH L = 68uH L = 47uH L=22uH Frequency vs Supply Voltage for L= 22, 47, 68 & 100uH 100 150 200 250 300 350 1 1.5 2 2.5 Supply Voltage Vcc (V) Frequency (k Hz) L = 100uH L = 68uH L = 47uH L = 22uH Efficiency vs Supply Voltage for L= 22, 47, 68 & 100uH 100 120 11 . 522 . 5 Supply Voltage Vvcc (V) Efficiency (%) L = 100uH L = 68uH L = 47uH L = 22uH ZXSC380 Document number: DS33616 Rev. 4 - 3 March 2024 © 2024 Copyright Diodes Incorporated. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGN

The ZXSC380 is non-synchronous PFM, DC-DC cont roller IC which, with a high performance internal transistor, for a high efficiency boost converter for use in single cell applications. A block diagram is shown in Figure 1. Figure 1 ZXSC380 Block diagram The on chip comparator forces the driver circuit and therefore the internal switching transistor to switch off when the voltage at ISENSE exceeds 20mV. This threshold is set by an internal reference circuit and divider. The voltage at ISENSE is taken from a current sense resistor connected in series with the emitter of the switching transistor. This resistor is chosen to give 20mV at I SENSE for an emitter current of 80mA. A monostable following the output of the comparator forces the turn-off time of the output stage to be typically 2.2/H9262s. This ensures that there is sufficient time to discharge a significant proportion of the energy stored in the inductor coil before the next On period. With every On pulse the switching transistor is kept on until the voltage across the current-sense resistor exceeds the threshold of the I SENSE input. The On-pulse length, and therefore the switching frequency, is determined by the programmed peak current, the input voltage and the input to output voltage differential. See applications section for details. The Driver circuit supplies the internal switching transistor with a fixed drive current. To maximize efficiency the internal transistor is switched quickly, typically being switched off within 30ns. RSENSE + VREF GND ISENSE R SENSE + VREF GND ISENSE VCC VOUT ZXSC380 Document number: DS33616 Rev. 4 - 3 March 2024 © 2024 Copyright Diodes Incorporated. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGN

gure 4 Switching frequency vs the supply voltage f or various inductor values Bootstrap operation The ZXSC380 can be operated in bootstrap mode, as shown in Figure 5, to operate down to 0.7V typical after the initial successful start up. The operation down to 0.7V typical allows further cell energy to be extracted beyond typically quoted end of battery voltage of approx. 0.9. This prolongs the battery use time. (Note: Some batteries may have low voltage protections and may switch the supply off.) The schotkky diodes, D1 and D2, should have a very low forward voltage, e.g. of such part is Zetex ZHCS400 (SOD323 package) or Zetex BAT54C (dual schotkky diode with common Cathode). The start up voltage is 0.9V typical without bootstrap, however, due to the additional schotkky, D1, being in the path of the supply to the Vcc pin, the start up voltage can be 1.1V typical for the bootstrap configuration. Figure 5 ZXSC380 in bootstrap mode Frequency vs Supply Voltage for L= 22, 47, 68 & 100uH 100 150 200 250 300 350 11 . 522 . 5 Supply Voltage Vcc (V) Frequency (kHz) L = 100uH L = 68uH L = 47uH L = 22uH VCC VOUT GND VIN GND 100uH LED1 ZXSC380 1uF ZXSC380 Document number: DS33616 Rev. 4 - 3 March 2024 © 2024 Copyright Diodes Incorporated. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGN

Document number: DS33616 Rev. 4 - 3 March 2024 © 2024 Copyright Diodes Incorporated. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGN

Note: Controlling dimensions are in millimeters. Approximate dimensions are provided in inches Dim. Millimeters Inches Dim. Millimeters Inches A - 1.12 - 0.044 e1 1.90 NOM 0.075 NOM e0 . 9 5 N O M0 . 0 3 7 N O M ----- E e L D A c E1L1 b 3 leads ZXSC380 Document number: DS33616 Rev. 4 - 3 March 2024 © 2024 Copyright Diodes Incorporated. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGN

lanstraße 59 D-81541 München Germany Telefon: (49) 89 45 49 49 0 Fax: (49) 89 45 49 49 49 europe.sales@zetex.com Americas Zetex Inc

700 Veterans Memorial Highway

Hauppauge, NY 11788 USA Telephone: (1) 631 360 2222 Fax: (1) 631 360 8222 usa.sales@zetex.com Asia Pacific Zetex (Asia Ltd) 3701-04 Metroplaza Tower 1 Hing Fong Road, Kwai Fong Hong Kong Telephone: (852) 26100 611 Fax: (852) 24250 494 asia.sales@zetex.com Corporate Headquarters Zetex Semiconductors plc Zetex Technology Park, Chadderton Oldham, OL9 9LL United Kingdom Telephone: (44) 161 622 4444 Fax: (44) 161 622 4446 hq@zetex.com Definitions Pro duct change Zetex Semiconductors reserves the right to alter, without notice, specifications, design, price or conditions of supply of any product or service. Customers are solely responsible for obtaining the latest relevant information before placing orders. Applications disclaimer The circuits in this design/application note are offered as desi gn ideas. It is the responsibility of the user to ensure that t he circuit is fit for the user’s application and meets with the user’s requirements. No representation or warranty is given and no liability whatsoev er is assumed by Zetex with respect to the accuracy or use of such in formation, or infringement of patents or other intellectual prop erty rights arising from such use or otherwise. Zetex does not assume any le gal responsibility or will not be held legally liable (whether in contract, tort (including negligence), breach of statutory duty, restricti on or otherwise) for any damages, loss of profit, business, con tract, opportunity or consequential loss in the use of these circuit applications, under any circumstances. Life support Zetex products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Zetex Semiconductors plc. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body or 2. support or sustain life and whose failure to perform when proper ly used in accordance with instructions for use provided in the labelling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support devi ce or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Reproduction The product specifications contained in this publication are issu ed to provide outline information only which (unless agreed by the company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services concerned. Terms and Conditions All products are sold subjects to Zetex’ terms and conditions of sale, and this disclaimer (save in the event of a conflict bet ween the two when the terms of the contract shall prevail) according to region, supplied at the time of order acknowledgement. For the latest information on technology, delivery terms and conditions and prices, please contact your nearest Zetex sales office. Quality of product Zetex is an ISO 9001 and TS16949 certified semiconductor manufacturer. To ensure quality of service and products we strongly advise the purchase of parts dire ctly from Zetex Semiconductors or one of our regionally authorized distributors. For a complete listing of authorized distributors please visit: www.zetex.com/salesnetwork Zetex Semiconductors does not warrant or accept any liability whatsoever in respect of any parts purchased through unauthorized sales channels. ESD (Electrostatic discharge) Semiconductor devices are susceptible to damage by ESD. Suitable precautions should be taken when handling and transporting devices. The possible damage to devices depends on the circumstances of the handling and transporting, and the nature of the device. The extent of damage can vary from immediate functional or parametric malfunc tion to degradation of function or performance in use over ti me. Devices suspected of being affected should be replaced. Green compliance Zetex Semiconductors is committed to envir onmental excellence in all aspects of its operations which includes meeting or exce eding regulatory requirements with respect to the use of hazardous s ubstances. Numerous successful programs have been implemented to reduce the use of hazardous substances and/or emissions. All Zetex components are compliant with the Ro HS directive, and through this it is supporting its customers in their compliance with WEEE and ELV directives. Product status key: “Preview” Future device intended for production at some point. Samples may be available “Active” Product status recommended for new designs “Last time buy (LTB)” Device will be discontinued and last time buy period and delivery is in effect “Not recommended for new designs” Device is still in production to support existing designs and production “Obsolete” Production has been discontinued Datasheet status key: “Draft version” This term denotes a very early datasheet ver sion and contains highly provisional information, which may change in any manner without notice. “Provisional version” This term denotes a pre-release datasheet. It provides a clear indication of anticipated performance. However, changes to the test conditions and specifications may occur, at any time and without notice. “Issue” This term denotes an issued datasheet cont aining finalized specifications. However, changes to specifications may occur, at any time and without notice. ZXSC380 Document number: DS33616 Rev. 4 - 3 March 2024 © 2024 Copyright Diodes Incorporated. All Rights Reserved. NOT RECOMMENDED FOR NEW DESIGN

Document number: DS33616 Rev. 4 - 3

11 March 2024

© 2024 Copyright Diodes Incorporated. All Rights Reserved. ZXSC380 ADVANCED INFORMATION IMPORTANT NOTICE 1. DIODES INCORPORATED (Diodes) AND ITS SUBSIDIARIES MAKE NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO ANY INFORMATION CONTAINED IN THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON -INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 2. The Information contained herein is for informational purpose only and is provided only to illustrate the operation of Diodes ’ products described herein and application examples. Diodes does not assume any liability arising out of the application or use of this document or any product described herein. This document is intended for skilled and technically trained engineering customers and users who d esign with Diodes’ products. Diodes’ products may be used to facilitate safety -related applications; however, in all instances customers and users are responsible for (a) selecting the appropriate Diodes products for their applications, (b) evaluating the suitability of Diodes ’ products for their intended applications, (c) ensuring their applications, which incorporate Diodes ’ products, comply the applicable legal and regulatory requirements as well as safety and functional-safety related standards, and (d) ensuring they design with appropriate safeguards (including testing, validation, quality co ntrol techniques, redundancy, malfunction prevention, and appropriate treatment for aging degradation) to minimize the risks associ ated with their applications. 3. Diodes assumes no liability for any application -related information, support, assistance or feedback that may be provided by Diodes from time to time. Any customer or user of this document or products described herein will assume all risks and liabilities a ssociated with such use, and will hold Diodes and all companies whose products are represented herein or on Diodes’ websites, harmless against al l damages and liabilities. 4. Products described herein may be covered by one or more United States, international or foreign patents and pending patent applications. Product names and markings noted herein may also be covered by one or more United States, international or fore ign trademarks and trademark applications. Diodes does not convey any license under any of its intellectual property rights or the rights of any third parties (including third parties whose products and services may be described in this document or on Diodes’ website) under this docu ment. 5. Diodes’ products are provided subject to Diodes’ Standard Terms and Conditions of Sale (https://www.diodes.com/about/company/terms-and-conditions/terms-and-conditions-of-sales/) or other applicable terms. This document does not alter or expand the applicable warranties provided by Diodes. Diodes does not warrant or accept any liability whatsoever in r espect of any products purchased through unauthorized sales channel. 6. Diodes’ products and technology may not be used for or incorporated into any products or systems whose manufacture, use or sale is prohibited under any applicable laws and regulations. Should customers or users use Diodes ’ products in contravention of any applicable laws or regulations, or for any unintended or unauthorized application, customers and users will (a) be solely responsible for any da mages, losses or penalties arising in connection therewith or as a result thereof, and (b) indemnify and hold Diodes and its representatives a nd agents harmless against any and all claims, damages, expenses, and attorney fees arising out of, directly or indirectly, any claim relating t o any noncompliance with the applicable laws and regulations, as well as any unintended or unauthorized application. 7. While efforts have been made to ensure the information contained in this document is accurate, complete and current, it may c ontain technical inaccuracies, omissions and typographical errors. Diodes does not warrant that information contained in this docume nt is error-free and Diodes is under no obligation to update or otherwise correct this information. Notwithstanding the foregoing, Diodes reserves the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any produ ct described herein. This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the final and determinative format released by Diodes. 8. Any unauthorized copying, modification, distribution, transmission, display or other use of this document (or any portion her eof) is prohibited. Diodes assumes no responsibility for any losses incurred by the customers or users or any third parties arising f rom any such unauthorized use. 9. This Notice may be periodically updated with the most recent version available at https://www.diodes.com/about/company/terms-and- conditions/important-notice The Diodes logo is a registered trademark of Diodes Incorporated in the United States and other countries. All other trademarks are the property of their respective owners. © 2024 Diodes Incorporated. All Rights Reserved. www.diodes.com NOT RECOMMENDED FOR NEW DESIGN