EL7516 ® Data Sheet October 27, 2004 600kHz/1.2MHz PWM Step-Up Regulator Features The EL7516 is a high frequency, high efficiency step-up voltage regulator operated at constant frequency PWM mode. With an internal 1.5A, 200mΩ MOSFET, it can deliver up to 600mA output current at over 90% efficiency. The selectable 600kHz and 1.2MHz allows smaller inductors and faster transient response. An external compensation pin gives the user greater flexibility in setting frequency compensation allowing the use of low ESR Ceramic output capacitors. • > 90% efficiency When shut down, it draws < 10µA of current and can operate down to 2.5V input supply. These features along with 1.2MHz switching frequency makes it an ideal device for portable equipment and TFT-LCD displays. The EL7516 is available in an 8-pin MSOP package with a maximum height of 1.1mm. The device is specified for operation over the full -40°C to +85°C temperature range. FN7333.3 • 1.6A, 200mΩ power MOSFET • VIN > 2.5V • 600kHz/1.2MHz switching frequency selection • Adjustable soft-start • Internal thermal protection • 1.1mm max height 8-pin MSOP package • Pb-free available (RoHS compliant) Applications • TFT-LCD displays • DSL modems • PCMCIA cards • Digital cameras Pinout • GSM/CDMA phones EL7516 (8-PIN MSOP) TOP VIEW • Portable equipment • Handheld devices COMP 1 8 SS FB 2 7 FSEL SHDN 3 6 VDD GND 4 5 LX Ordering Information PACKAGE TAPE & REEL PKG. DWG. # EL7516IY 8-Pin MSOP - MDP0043 EL7516IY-T7 8-Pin MSOP 7” MDP0043 EL7516IY-T13 8-Pin MSOP 13” MDP0043 EL7516IYZ (See Note) 8-Pin MSOP (Pb-Free) - MDP0043 EL7516IYZ-T7 (See Note) 8-Pin MSOP (Pb-Free) 7” MDP0043 EL7516IYZ-T13 (See Note) 8-Pin MSOP (Pb-Free) 13” MDP0043 PART NUMBER NOTE: Intersil Pb-free products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020C. 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright © Intersil Americas Inc. 2002-2004. All Rights Reserved. Elantec is a registered trademark of Elantec Semiconductor, Inc. All other trademarks mentioned are the property of their respective owners. EL7516 Absolute Maximum Ratings (TA = 25°C) LX to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18V VDD to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6V COMP, FB, SHDN, SS, FSEL to GND . . . . . . -0.3V to (VDD +0.3V) Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C Operating Ambient Temperature . . . . . . . . . . . . . . . .-40°C to +85°C Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . +135°C CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless otherwise noted, all tests are at the specified temperature and are pulsed tests, therefore: TJ = TC = TA Electrical Specifications PARAMETER VIN = 3.3V, VOUT = 12V, IOUT = 0mA, FSEL = GND, TA = 25°C unless otherwise specified. DESCRIPTION CONDITIONS MIN TYP MAX UNIT 10 µA IQ1 Quiescent Current - Shut-down SHDN = 0V 0.6 IQ2 Quiescent Current - Not Switching SHDN = VDD, FB = 1.3V 0.7 IQ3 Quiescent Current - Switching SHDN = VDD, FB = 1.0V 1.3 2 mA VFB Feedback Voltage 1.294 1.309 V IB-FB Feedback Input Bias Current 0.01 0.5 µA VDD Start-Up Input Voltage Range 5.5 V DMAX-600kHz Maximum Duty Cycle FSEL = 0V 84 90 % DMAX-1.2MHz Maximum Duty Cycle FSEL = VDD 84 90 % ILIM Current Limit - Max Peak Input Current 1.3 1.5 A ISHDN Shut-down Input Bias Current SHDN = 0V 0.01 RDS-ON Switch ON Resistance VDD = 2.7V, ILX = 1A 0.2 ILX-LEAK Switch Leakage Current VSW = 18V 0.01 ∆VOUT/∆VIN Line Regulation 3V < VIN < 5.5V, VOUT = 12V 0.1 % ∆VOUT/∆IOUT Load Regulation VIN = 3.3V, VOUT = 12V, IO = 30mA to 200mA 6.7 mV/A FOSC1 Switching Frequency Accuracy FSEL = 0V 500 620 740 kHz FOSC2 Switching Frequency Accuracy FSEL = VDD 1000 1250 1500 kHz VIL SHDN, FSEL Input Low Level 0.5 V VIH SHDN, FSEL Input High Level GM Error Amp Tranconductance AV Voltage Gain VDD-ON VDD UVLO On Threshold 2.40 2.51 2.60 V VDD-OFF VDD UVLO Off Threshold 2.20 2.30 2.40 V ISS Soft-start Charge Current 4 6 8 µA RCS Current Sense Transresistance 0.08 V/A OTP Over Temperature Protection 130 °C 1.272 2.6 mA 0.1 Ω 3 2.7 ∆I = 5µA 90 µA V 130 170 350 2 µA 1µ/Ω V/V FN7333.3 EL7516 Block Diagram SHDN FSEL REFERENCE GENERATOR VDD OSCILLATOR SS SHUTDOWN & START-UP CONTROL LX PWM LOGIC CONTROLLER FET DRIVER COMPARATOR CURRENT SENSE GND FB GM AMPLIFIER COMP Pin Descriptions PIN NUMBER PIN NAME DESCRIPTION 1 COMP Compensation pin. Output of the internal error amplifier. Capacitor and resistor from COMP pin to ground. 2 FB Voltage feedback pin. Internal reference is 1.294V nominal. Connect a resistor divider from VOUT. VOUT = 1.294V (1 + R1 / R2). See Typical Application Circuit. 3 SHDN 4 GND 5 LX 6 VDD Analog power supply input pin. 7 FSEL Frequency select pin. When FSEL is set low, switching frequency is set to 620kHz. When connected to high or VDD, switching frequency is set to 1.25MHz. 8 SS Shutdown control pin. Pull SHDN low to turn off the device. Analog and power ground. Power switch pin. Connected to the drain of the internal power MOSFET. Soft-start control pin. Connect a capacitor to control the converter start-up. Typical Application Circuit R3 3.9kΩ 1 COMP R1 85.2kΩ C5 R2 4.7nF 10kΩ 2 FB 3 SHDN 4 GND SS 8 FSEL 7 VDD 6 LX 5 C3 27nF C4 2.7V TO 5.5V + C1 0.1µF 22µF 10µH D1 3 + C2 12V 22µF FN7333.3 EL7516 Typical Performance Curves 95 0.6 LOAD REGULATION (%) EFFICIENCY (%) 0.4 90 85 80 0.2 0 -0.2 -0.4 -0.6 -0.8 75 0 100 200 300 -1 400 0 50 100 IOUT (mA) LOAD REGULATION (%) EFFICIENCY (%) 300 350 1 85 80 0 100 200 300 0.5 0 -0.5 -1 400 0 50 100 150 200 250 300 350 IOUT (mA) IOUT (mA) FIGURE 3. EFFICIENCY - 3.3V VIN TO 12V VOUT @ 620kHz FIGURE 4. LOAD REGULATION - 3.3V VIN TO 12V VOUT @ 620kHz 95 LOAD REGULATION (%) 1 90 EFFICIENCY (%) 250 FIGURE 2. LOAD REGULATION - 3.3V VIN TO 12V VOUT @ 1.3MHz 90 85 80 75 70 200 IOUT (mA) FIGURE 1. EFFICIENCY - 3.3V VIN TO 12V VOUT @ 1.3MHz 75 150 0 100 200 300 400 500 IOUT (mA) FIGURE 5. EFFICIENCY - 3.3V VIN TO 9V VOUT @ 1.2MHz 4 0.5 0 -0.5 -1 0 100 200 300 400 500 IOUT (mA) FIGURE 6. LOAD REGULATION - 3.3V VIN TO 9V VOUT @ 1.2MHz FN7333.3 EL7516 Typical Performance Curves (Continued) 1 LOAD REGULATION (%) EFFICIENCY (%) 90 85 80 75 0 100 200 300 400 0.6 0.2 -0.2 -0.6 -1 500 0 100 200 IOUT (mA) 300 400 500 IOUT (mA) FIGURE 7. EFFICIENCY - 3.3V VIN TO 9V VOUT @ 600kHz FIGURE 8. LOAD REGULATION - 3.3V VIN TO 9V VOUT @ 600kHz 0.8 95 LOAD REGULATION (%) EFFICIENCY (%) 0.6 90 85 80 0.4 0.2 1 -0.2 -0.4 -0.6 -0.8 75 0 100 200 300 400 500 -1 600 0 100 200 IOUT (mA) 300 400 500 600 IOUT (mA) FIGURE 9. EFFICIENCY - 5V VIN TO 12V VOUT @ 1.2MHz FIGURE 10. LOAD REGULATION - 5V VIN TO 12V VOUT @ 1.2MHz 0.8 92 LOAD REGULATION (%) EFFICIENCY (%) 0.6 90 88 86 0.4 0.2 1 -0.2 -0.4 -0.6 -0.8 84 0 100 200 300 400 500 600 IOUT (mA) FIGURE 11. EFFICIENCY - 5V VIN TO 12V VOUT @ 600kHz 5 -1 0 100 200 300 400 500 600 IOUT (mA) FIGURE 12. LOAD REGULATION - 5V VIN TO 12V VOUT @ 600kHz FN7333.3 EL7516 Typical Performance Curves (Continued) 0.6 95 LOAD REGULATION (%) EFFICIENCY (%) 0.4 90 85 80 0.2 0 -0.2 -0.4 -0.6 -0.8 75 0 400 200 800 600 -1 1K 0 200 400 FIGURE 13. EFFICIENCY - 5V VIN TO 9V VOUT @ 1.2MHz LINE REGULATION (%) LINE REGULATION (%) 0.1 1.2MHz 0 600kHz -0.1 -0.2 2 4 3 0.05 1.2MHz 0 600kHz -0.05 -0.1 2.5 6 5 VOUT=8V IOUT=80mA 4.5 3.5 FIGURE 15. LINE REGULATION FIGURE 16. LINE REGULATION 95 0.5 1.2MHz LOAD REGULATION (%) 600kHz 90 EFFICIENCY (%) 6.5 5.5 VIN (V) VIN (V) 85 1.2MHz 80 75 70 10 1K FIGURE 14. LOAD REGULATION - 5V VIN TO 9V VOUT @ 1.2MHz VOUT=12V IOUT=80mA 0.1 800 IOUT (mA) IOUT (mA) 0.2 600 110 210 310 410 510 610 IOUT (mA) FIGURE 17. EFFICIENCY vs IOUT - 3.3V TO 8V 6 0.3 0.1 -0.1 600kHz -0.3 -0.5 0 100 200 300 400 500 600 IOUT (mA) FIGURE 18. LOAD REGULATION - 3.3V TO 8V FN7333.3 EL7516 (Continued) 94 1.29 92 1.28 90 1.27 FREQUENCY (MHz) EFFICIENCY (%) Typical Performance Curves 88 1.2MHz 86 84 82 80 600kHz 78 76 0 200 600 400 800 1.26 1.25 1.24 1.23 1.22 1.21 1K 1.2 2.5 1.2K 3 IOUT (mA) 4.5 4 5 5.5 VIN (V) FIGURE 19. EFFICIENCY vs IOUT FIGURE 20. FREQUENCY (1.2MHz) vs VIN 670 93 660 91 EFFICIENCY (kHz) FREQUENCY (kHz) 3.5 650 640 630 620 89 87 85 83 610 600 2.5 3 3.5 4.5 4 5 5.5 81 VIN (V) 0 200 400 600 800 1K IOUT (mA) FIGURE 21. FREQUENCY (600kHz) vs VIN FIGURE 22. EFFICIENCY - 5V VIN TO 9V VOUT @ 600kHz LOAD REGULATION (%) 0.4 VIN = 3.3V VOUT = 12V IOUT = 50mA TO 300mA 0.2 0 200mV/DIV -0.2 -0.4 0 200 400 600 800 1K 0.1ms/DIV IOUT (mA) FIGURE 23. LOAD REGULATION - 5V VIN TO 9V VOUT @ 600kHz 7 FIGURE 24. TRANSIENT REPONSE - 600kHz FN7333.3 EL7516 Typical Performance Curves (Continued) 1 VIN = 3.3V VOUT = 12V IOUT = 50mA TO 300mA JEDEC JESD51-7 HIGH EFFECTIVE THERMAL CONDUCTIVITY TEST BOARD POWER DISSIPATION (W) 0.9 200mV/DIV 870mW 0.8 0.7 θ JA = 0.6 0.5 0.4 M SO 11 P8 5° C/ W 0.3 0.2 0.1 0 0.1ms/DIV 0 25 50 75 85 100 125 AMBIENT TEMPERATURE (°C) FIGURE 25. TRANSIENT RESPONSE - 1.2MHz POWER DISSIPATION (W) 0.6 FIGURE 26. PACKAGE POWER DISSIPATION vs AMBIENT TEMPERATURE JEDEC JESD51-3 LOW EFFECTIVE THERMAL CONDUCTIVITY TEST BOARD 0.5 486mW 0.4 θ JA = 0.3 M SO P8 20 6° C/ W 0.2 0.1 0 0 25 50 75 85 100 125 AMBIENT TEMPERATURE (°C) FIGURE 27. PACKAGE POWER DISSIPATION vs AMBIENT TEMPERATURE Applications Information The EL7516 is a high frequency, high efficiency boost regulator operated at constant frequency PWM mode. The boost converter stores energy from an input voltage source and deliver it to a higher output voltage. The input voltage range is 2.5V to 5.5V and output voltage range is 5V to 18V. The switching frequency is selectable between 600KHz and 1.2MHz allowing smaller inductors and faster transient response. An external compensation pin gives the user greater flexibility in setting output transient response and tighter load regulation. The converter soft-start characteristic can also be controlled by external CSS capacitor. The SHDN pin allows the user to completely shut-down the device. Boost Converter Operations Figure 28 shows a boost converter with all the key components. In steady state operating and continuous conduction mode where the inductor current is continuous, 8 the boost converter operates in two cycles. During the first cycle, as shown in Figure 29, the internal power FET turns on and the Schottky diode is reverse biased and cuts off the current flow to the output. The output current is supplied from the output capacitor. The voltage across the inductor is VIN and the inductor current ramps up in a rate of VIN / L, L is the inductance. The inductance is magnetized and energy is stored in the inductor. The change in inductor current is: V IN ∆I L1 = ∆T1 × --------L D ∆T1 = -----------F SW D = Duty Cycle I OUT ∆V O = ---------------- × ∆T 1 C OUT FN7333.3 EL7516 During the second cycle, the power FET turns off and the Schottky diode is forward biased, Figure 30. The energy stored in the inductor is pumped to the output supplying output current and charging the output capacitor. The Schottky diode side of the inductor is clamp to a Schottky diode above the output voltage. So the voltage drop across the inductor is VIN - VOUT. The change in inductor current during the second cycle is: L D VOUT VIN COUT CIN EL7516 IL ∆IL2 V IN – V OUT ∆I L = ∆T2 × -------------------------------L ∆T2 ∆VO 1–D ∆T2 = ------------F SW For stable operation, the same amount of energy stored in the inductor must be taken out. The change in inductor current during the two cycles must be the same. ∆I1 + ∆I2 = 0 V IN 1 – D V IN – V OUT D ------------ × --------+ ------------- × -------------------------------- = 0 L F SW L F SW V OUT 1 ---------------- = ------------1–D V IN L D VOUT VIN FIGURE 30. BOOST CONVERTER - CYCLE 2, POWER SWITCH OPEN Output Voltage An external feedback resistor divider is required to divide the output voltage down to the nominal 1.294V reference voltage. The current drawn by the resistor network should be limited to maintain the overall converter efficiency. The maximum value of the resistor network is limited by the feedback input bias current and the potential for noise being coupled into the feedback pin. A resistor network less than 100K is recommended. The boost converter output voltage is determined by the relationship: R 1⎞ ⎛ V OUT = V FB × ⎜ 1 + -------⎟ R 2⎠ ⎝ COUT CIN The nominal VFB voltage is 1.294V. EL7516 Inductor Selection FIGURE 28. BOOST CONVERTER L VOUT VIN COUT CIN EL7516 The inductor selection determines the output ripple voltage, transient response, output current capability, and efficiency. Its selection depends on the input voltage, output voltage, switching frequency, and maximum output current. For most applications, the inductance should be in the range of 2µH to 33µH. The inductor maximum DC current specification must be greater than the peak inductor current required by the regulator. The peak inductor current can be calculated: I OUT × V OUT V IN × ( V OUT – V IN ) I L ( PEAK ) = ------------------------------------ + 1 ⁄ 2 × ----------------------------------------------------V IN L × V OUT × FREQ IL ∆IL1 ∆T1 ∆VO FIGURE 29. BOOST CONVERTER - CYCLE 1, POWER SWITCH CLOSED Output Capacitor Low ESR capacitors should be used to minimized the output voltage ripple. Multilayer ceramic capacitors (X5R and X7R) are preferred for the output capacitors because of their lower ESR and small packages. Tantalum capacitors with higher ESR can also be used. The output ripple can be calculated as: I OUT × D ∆V O = --------------------------- + I OUT × ESR F SW × C O 9 FN7333.3 EL7516 For noise sensitive application, a 0.1µF placed in parallel with the larger output capacitor is recommended to reduce the switching noise coupled from the LX switching node. Shut-Down Control Schottky Diode Maximum Output Current In selecting the Schottky diode, the reverse break down voltage, forward current and forward voltage drop must be considered for optimum converter performance. The diode must be rated to handle 1.5A, the current limit of the EL7516. The breakdown voltage must exceed the maximum output voltage. Low forward voltage drop, low leakage current, and fast reverse recovery will help the converter to achieve the maximum efficiency. The MOSFET current limit is nominally 1.5A and guaranteed 1.3A. This restricts the maximum output current IOMAX based on the following formula: Input Capacitor The value of the input capacitor depends the input and output voltages, the maximum output current, the inductor value and the noise allowed to put back on the input line. For most applications, a minimum 10µF is required. For applications that run close to the maximum output current limit, input capacitor in the range of 22µF to 47µF is recommended. The EL7516 is powered from the VIN. To. High frequency 0.1µF by-pass cap is recommended to be close to the VIN pin to reduce supply line noise and ensure stable operation. Loop Compensation The EL7516 incorporates an transconductance amplifier in its feedback path to allow the user some adjustment on the transient response and better regulation. The EL7516 uses current mode control architecture which has a fast current sense loop and a slow voltage feedback loop. The fast current feedback loop does not require any compensation. The slow voltage loop must be compensated for stable operation. The compensation network is a series RC network from COMP pin to ground. The resistor sets the high frequency integrator gain for fast transient response and the capacitor sets the integrator zero to ensure loop stability. For most applications, the compensation resistor in the range of 2K to 7.5K and the compensation capacitor in the range of 3nF to 10nF. When shut-down in is pulled low, the EL7516 is shut-down reducing the supply current to <3µA. I L = I L-AVG + ( 1 ⁄ 2 × ∆I L ) where: IL = MOSFET current limit IL-AVG = average inductor current ∆IL = inductor ripple current V IN × [ ( V O + V DIODE ) – V IN ] ∆I L = -----------------------------------------------------------------------------L × ( V O + V DIODE ) × F S VDIODE = Schottky diode forward voltage, typically, 0.6V FS = switching frequency, 600KHz or 1.2MHz I OUT I L-AVG = ------------1–D D = MOSFET turn-on ratio: V IN D = 1 – -------------------------------------------V OUT + V DIODE The following table gives typical maximum Iout values for 1.2MHz switching frequency and 22µH inductor: TABLE 1. VIN (V) VOUT (V) IOMAX (mA) 2.5 5 570 2.5 9 325 2.5 12 250 Soft-Start 3.3 5 750 The soft-start is provided by an internal 6µA current source charges the external CSS, the peak MOSFET current is limited by the voltage on the capacitor. This in turn controls the rising rate of the output voltage. The regulator goes through the start-up sequence as well after the SHDN pin is pulled to HI. 3.3 9 435 3.3 12 330 5 9 650 5 12 490 Thermal Performance Frequency Selection The EL7516 switching frequency can be user selected to operate at either at constant 620kHz or 1.25MHz. Connecting FSEL pin to ground sets the PWM switching frequency to 620kHz. When connect FSEL high or VDD, switching frequency is set to 1.25MHz. 10 The EL7516 uses a fused-lead package, which has a reduced θJA of 100°C/W on a four-layer board and 115°C/W on a two-layer board. Maximizing copper around the ground pins will improve the thermal performance. This device also has internal thermal shut-down set at around 130°C to protect the component. FN7333.3 EL7516 Layout Considerations To achieve highest efficiency, best regulation and most stable operation, a good printed circuit board layout is essential. It is strongly recommended that the demoboard layout to be followed as closely as possible. Use the following general guidelines when laying out the print circuit board: 1. Place C4 as close to the VDD pin as possible. C4 is the supply bypass capacitor of the device. 2. Keep the C1 ground, GND pin and C2 ground as close as possible. 3. Keep the two high current paths a) from C1 through L1, to the LX pin and GND and b) from C1 through L1, D1, and C2 as short as possible. 4. High current traces should be short and as wide as possible. 5. Place feedback resistor close to the FB pin to avoid noise pickup. 6. Place the compensation network close to the COMP pin. The demo board is a good example of layout based on these principles; it is available upon request. All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 11 FN7333.3