SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r November 2012 Rev. 2. 2.0 GENERAL DESCRIPTION APPLICATIONS The SP6669 is a synchronous current mode PWM step down (buck) converter capable of delivering up to 600mA of current. It features a pulse skip mode (PSM) for light load efficiency and a LDO mode for 100% duty cycle. With a 2.5V to 5.5V input voltage range and a 1.5MHz switching frequency, the SP6669 allows the use of small surface mount inductors and capacitors ideal for battery power ed portable applications. The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Low output voltages are easily supported with the 0.6V feedback reference voltage. The SP6669 is available in an adjustab le output voltage version, using an external resistor divider circuit, as well as fixed output voltage v ersions of 1.2V, 1.5V and 1.8V. Built - in over temperature and output over voltage lock - out protections insure safe operations under abnormal operating conditions. The SP6669 is offered in a RoHS compliant, ³JUHHQ´KDORJHQIUHH - pin SOT23 package. TYPICAL APPLICATION x Portable Equipments x Battery Operated Equipments x Audio - Video Equipments x Networking & Telecom Equipments FEATURES x Guaranteed 600mA Output Current In put Voltage: 2.5V to 5.5V x 1.5MHz PWM Current Mode Control 100% Duty Cycle LDO Mode Operations Achieves 95% Efficiency x Fixed/Adjustable Output Voltage Range As Low as 0.6V with ±3% Accuracy 1.2V, 1.5V, 1.8V Fixed Voltage Options x Excellent Line/Load Response Transient x 200 µA Quiescent Current x Over Temperature Protection x 5R+6&RPSOLDQW³*UHHQ´+DORJ 5 - Pin SOT23 Package DIAGRAM Fig. 1: SP6669 Application Diagram Exar Corporation 48720 Kato Road, Fremont CA 94538, USA (Adj. version shown) Tel. +1 510 668 www.exar.com - 70 00 ±Fax. +1 510 668 - 70 01 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r ABSOLUTE MAXIMUM RAT INGS OPERATING RATINGS These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolut e maximum rating conditions for extended periods of time may affect reliability. Input Voltage Range V IN ............................... Operating Temperature Range ................... 7KHUPDO5HVLVWDQFHLJ JA ................................ 7KHUPDO5HVLVWDQFHLJ Jc................................ Input Voltage VIN ................................ ....... - 0.3V to 6.0V Enable VFB Voltage ................................ ....... - 0.3V to V IN SW Voltage ................................ ...... - 0.3V to ( VIN +0.3V) PMOS Switch Source Current (DC) ........................ 800mA NMOS Switch Sink Current ................................ .. 800mA Peak Switch Sink/Source Current ............................ 1.3A Operating Junction Temperature 1 .......................... 125 °C Storage Temperature .............................. - 65°C to 150°C Lead Temperature (Soldering, 10 sec) .................... 260°C ESD Rating (HBM - Human Body Model) .................... 2kV ESD Rating (MM - Machine Model) ........................... 200V Note 1: T J is a function of the ambient temperature T power dissipation P D (T J= T A + P D x 250°C/W). ELECTRICAL SPECIFICA 2.7V to 5.5V - 40°C to 85 °C ..... 250 °C/W ....... 90 °C/W A and TIONS Specifications with standard type are for an Operating Junction Temperature of T J = 25°C only; limits applying over the full 2SHUDWLQJ -XQFWLRQ 7HPSHUDWXUH UDQJH DUH GHQRWHG E\ D ³´ 0LQLPXP DQ design, or statistical correlation. Typical values represent the most likely parametric norm at T A = 25°C, and are provided for reference purposes only. Unless otherwise indicated, V IN = 3.6 V. Parameter Feedback Current I Min. Typ. VFB Regulated Feedback Voltage V FB 0.588 0.600 Reference Voltage Line 5HJXODWLRQƩ9 FB 2XWSXW9ROWDJH$FFXUDF\Ʃ9 -3 OUT% 50 20 Output Over - Voltage Lockout Ʃ9 OVL 7.8 2.5 Output Voltage Line Regulation Ʃ9 OUT Peak Inductor Current I PK Output Voltage Load Regulation VLOADREG Quiescent Current 2 IQ Shutdown Current I SHTDWN Oscillator Frequency f OSC 1.2 Max. Units ±30 nA 0.612 V 0.4 %/V Conditions TA=25°C VIN =2.5V to 5.5V +3 % 80 mV Ʃ9 OVL = V OVL ±VFB (Adj.) 13 % Ʃ9 OVL = V OVL ±VOUT (Fixed) 0.4 %/V 1.0 A 0.5 % VIN =2.5V to 5.5V VIN =3V, V FB=0.5V or V cycle <35% 200 340 µA VFB=0.5V or 0.1 1 µA VEN=0V, V 1.5 1.8 MHz 290 Hz PFET 0.45 0.55 ƻ I SW =100mA NFET 0.40 0.50 ƻ I SW =100mA ±1 µA 1.2 V V ±1 µA Enable Threshold V EN Shutdown Threshold V EN Leakage Current I EN EN 0.4 VOUT=90% VFB=0.6V or V OUT=100% VFB=0V or V OUT=0V RDS(ON) of NMOS R LSW Duty IN =4.2V RDS(ON) of PMOS R SW Leakage I OUT =90%, VEN=0V, V SW =0V or 5V, V IN =5V Note 1: The Switch Current Limit is related to the Duty Cycle. Please refer to figure 15 for details. Note 2: Dynamic quiescent current is higher due to the gate charge being delivered at the switching frequency. © 2012 Exar Corporation 2/ 11 Rev. 2. 2.0 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r BLOCK DIAGRAM Fig. 2: SP6669 Block Diagram PIN ASSIGNMENT Fig. 3: SP6669 Pin Assignment © 2012 Exar Corporation 3/ 11 Rev. 2. 2.0 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r PIN DESCRIPTION Name Pin Number Description EN 1 Enable Pin. Do not leave the pin floating. VEN<0.4V: Shutdown mode VEN>1.2V: Device enabled GND 2 Ground Signal SW 3 Switching Node VIN 4 Power Supply Pin. Must be decoupled to ground with a 4.7µF or greater ceramic capacitor. Adjustable Version Feedback Input Pin. Connect VFB to the center point of the resistor divider. VFB 5 VOUT Fixed Output Voltage Version, Output Voltage Pin. An internal resistive divider divides the output voltage down for comparison to the internal reference voltage. ORDERING INFORMATION Temperature Range Part Number Marking Packing Quantity Package Note 1 SP6669AEK - L/TRR3 - &7 A& QBWW SOT23 - 5 3K/Tape & Reel Halogen Free SP6669BEK - L/TRR3 - &7 A& RBWW SOT23 - 5 3K/Tape & Reel Halogen Free SP6669CEK - L/TRR3 - &7 A& SBWW SOT23 - 5 3K/Tape & Reel Halogen Free SP6669DEK - L/TRR3 - &7 A& TBWW SOT23 - 5 3K/Tape & Reel Halogen Free SP6669EB ³<<´ Note 2 Adjustable output voltage 1.2V fixed output voltage 1.5V fixed output voltage 1.8V fixed output voltage SP6669 Evaluation Board <HDU ±³::´ :RUN:HHN ±³;´ /RW1XPEHU ; when applicable. Note that the SP6669 series is packaged in Tape and Reel with a reverse part orientation as per the following diagram © 2012 Exar Corporation 4/ 11 Rev. 2. 2.0 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r TYPICAL PERFORMANCE CHARACTERISTICS All data taken at V IN = 2.7V to 5.5V, T Information section of this datasheet. J = T A = 25°C, unless otherwise specified - Schematic and BOM from Application Fig. 4: Efficiency vs Output Current (mA) Fig. 5: Efficiency vs Output Current (mA) Fig. 6: Efficiency vs Fig. 7: Efficiency vs Output Current (mA) Output Current (mA) Fig. 9: Reference Voltage vs Temperature Fig. 8: Output Voltage vs Load Current © 2012 Exar Corporation 5/ 11 Rev. 2. 2.0 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r Fig. 10 : R DS(ON) vs Temperature Fig. 11 : R DS(ON) vs Input Voltage Fig. 12 : Dynamic Supply Current vs Temperature Fig. 13 : Dynamic Supply Current vs Supply Voltage Fig. 14 : Oscillator Frequency vs Temperature Fig. 15 : Oscillator Frequency vs Supply Voltage © 2012 Exar Corporation 6/ 11 Rev. 2. 2.0 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r Fig. 16 : Discontinuous Operation Fig. 17 : Start - up from Shutdown Fig. 18 : Load Step Fig. 19 : Load Step Fig. 20 : Load Step Fig. 21 : Load Step © 2012 Exar Corporation 7/ 11 Rev. 2. 2.0 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r THEORY OF OPERATION The ESR rating of the capacitor is an important parameter to select C OUT. The output ripple VOUT is determined by: A PPLICATIONS The typical application circuit of the adjustable output voltage option and the fixed output voltage option are shown below. Eq. 3: § 1 'VOUT #'I L ¨ ¨ESR 8 f COUT © · ¸ ¸ ¹ Higher values, lower cost ceramic capacitors are now available in smaller sizes. These capacitors have high ripple currents, high voltage ratings and low ESR that makes them ideal for switching regulator applications. As COUT does not affect the internal control loop stability, its value can be optimized to balance very low output ripple and circuit size. It is recommended to use an X5R or X7R rated capacitors which have the best temperature and voltage characteristics of all the ceramics for a given value and size. Fig. 22 : Adjustable Output Voltage Version O UTPUT V OLTAGE ±A DJUSTABLE V ERSION The adjustable output voltage version is determined by: Fig. 23 : Fixed Output Voltage Version Eq. 4: I NDUCTOR SELECTION Inductor ripple current and core saturation are two factors considered to select the inductor value. Eq. 1: 'I L § VOUT 1 VOUT ¨ 1 ¨ f L © VIN Although the SP6669 has an on board over temperature circuitry, the total power dissipation it can support is based on the package thermal capabilities. The formula to ensure safe operation is given in note 1. IN PCB L AYOUT The following PCB layout guidelines should be taken into account to ensure proper operation and performance of the SP6669: CIN AND COUT S ELECTION 1- The GND, SW and V short, direct and wide. A low ESR input capacitor can prevent large voltage transients at V IN . The RMS current rating of the input capacit or is required to be larger than I RMS calculated by: Eq. 2: I RMS #I OMAX © 2012 Exar Corporation § R2 · ¨ 0.6V 1 ¸ ¨ ¸ © R1 ¹ T HERMAL CONSIDERATIONS · ¸ ¸ ¹ Equation 1 shows the inductor ripple current as a function of the frequency, inductance, V and V OUT. It is recommended to set the ripple current between 30% to 40% of the maximum load current . A low ESR inductor is preferred. VOUT IN traces shoul d be kept 2- VFB pin must be connected directly to the feedback resistors. The resistor divider network must be connected in parallel to the COUT capacitor. VOUT VIN VOUT 3- The input capacitor C close as possible to the V VIN 8/ 11 must be kept as pin. IN IN Rev. 2. 2.0 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r 4- The SW and VFB nodes should be kept as separate as possible to minize possible effects from the high frequency and voltage swings of the SW node. 5- The ground plates of C kept as close as possible. IN D ESIGN EXAMPLE In a single Lithium -Ion battery powered application, the V IN range is about 2.7V to 4.2V. The desired output voltage is 1.8V. and C OUT should be The inductor value needed can be calculated using the following equation O UPTUT V OLTAGE R IPPLE FOR V IN CLOSE TO V OUT L When the input voltage V IN is close to the output voltage V OUT, the SP6669 transitions smoothly from the switching PWM converter mode into a LDO mode. The following diagram shows the output voltage ripple versus the input voltage for a 3.3 V output setting and a 200mA current load. Fig. 24 : VOUT Ripple Voltage for VIN decreasing close to V © 2012 Exar Corporation § VOUT 1 VOUT ¨ 1 ¨ f 'I L © VIN · ¸ ¸ ¹ Substituting V OUT=1.8V, V IN 9Ʃ, L=180mA to 240mA (30% to 40%) and f=1.3MHz gives ܮൌʹǤ ͺ ߤܪ ݐ ͵Ǥ ͺͳ ߤܪ A 3.3 µH inductor can be chosen with this application. An inductor of greater value with less equivalent series resistance would provide better efficiency. The CIN capacitor requires an RMS current rating of at least I LOAD(MAX) /2 and low ESR. In most cases, a ceramic capacitor will sati sfy this requirement. OUT 9/ 11 Rev. 2. 2.0 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r PACKAGE SPECIFICATIO N 5 - P IN SOT23 Unit: mm Symbol Min. Nom. Max A 0.90 1.30 1.40 A1 0.00 0.075 0.15 A2 0.90 1.20 1.25 b 0.30 - 0.50 c 0.08 - 0.20 D 2.80 2.90 3.00 E 2.60 2.80 3.00 E1 1.50 1.60 1.70 e 0.95 BSC e1 1.90 BSC L 0.30 0.45 0.60 0.60 REF L1 0.25 BSC L2 Ĭ 0 5 10 Ĭ 3 5 7 Ĭ 6 8 10 Note: JEDEC Outline MO - 178 AA © 2012 Exar Corporation 10 / 11 Rev. 2. 2.0 SP 6 6 6 9 6 0 0 m A 1 . 5 M H z S y n c h r o n o u s S t e p D o w n Co n v e r t e r REVISION HISTORY Revision Date Description 2.0 .0 07/15/2011 Reformat of datasheet Updated package specification 2.1.0 02/07/2012 Updated Typical Application 2.2.0 11/08/2012 Reformat of datasheet (New logo) Updated Absolute Maximum Ratings, Lead Temperature (Soldering, 10 sec) FOR FURTHER ASSISTAN schematics and Design example to 260 ° C CE Email: [email protected] powertechsup [email protected] Exar Technical Documentation: http://www.exar.com/TechDoc/default.aspx? EXAR CORPORATION H EADQUARTERS AND SALES O FFICES 48720 Kato Road Fremont, CA 94538 ±USA Tel.: +1 (510) 668 - 7000 Fax: +1 (510) 668 -7030 www.exar.com NOTICE EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein, conveys no li cense under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained here in are only for illustration purposes and may vary depending upon a XVHU¶VVSHFLILFDSSOLFDWLRQ:KLOH the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of th e product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writing, assurances to it s satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Reproduction, in part or whole, without the prior wr © 2012 Exar Corporation itten consent of EXAR Corporation is prohibited. 11 / 11 Rev. 2. 2.0