FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch Features Description ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The FAN5330 is an LED driver that features fixed frequency mode operation and an integrated FET switch. This device is designed to operate at high switching frequencies in order to minimize switching noise measured at the battery terminal of hand-held communications equipment. Quiescent current in both normal and shutdown mode is designed to be minimal in order to extend battery life. Normal or shutdown mode can be selected by a logic level shutdown circuitry. 1.5MHz Switching Frequency Low Noise Adjustable Output Voltage 0.7W Output Power Capability Low Shutdown Current: <1µA Cycle-by-Cycle Current Limit Low Feedback Voltage (110mV) Over-Voltage Protection Fixed-Frequency PWM Operation Internal Compensation Thermal Shutdown 5-Lead SOT23 Package The low ON-resistance of the internal N-channel switch ensures high efficiency and low power dissipation. A cycle-by-cycle current limit circuit keeps the peak current of the switch below a typical value of 1.5A. The FAN5330 is available in a 5-lead SOT23 package. Applications ■ ■ ■ ■ ■ Cell Phones PDAs Handheld Equipment Display Bias LED Bias Typical Application BAT54 L VIN 6.8µH to 10µH CIN VOUT COUT 0.47µF 2.2µF ILED 5 SW V 1 FAN5330 IN 4 ON OFF SHDN FB GND 3 2 R Figure 1. Typical Application Diagram ©2005 Fairchild Semiconductor Corporation FAN5330 Rev. 1.0.1 1 www.fairchildsemi.com FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch August 2005 Top View SW VIN GND FB SHDN 5-Lead SOT-23 Figure 2. Pin Assignment Pin Description Pin No. Pin Name 1 SW 2 GND 3 FB 4 SHDN 5 VIN Pin Description Switching Node. Analog and Power Ground. Feedback Pin. Feedback node that connects to an external current set resistor. Shutdown Control Pin. Logic HIGH enables, logic LOW disables the device. Input Voltage Pin. 2 FAN5330 Rev. 1.0.1 www.fairchildsemi.com FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch Pin Assignment Parameter Min. Max. Unit 6.0 V FB, SHDN to GND -0.3 VIN + 0.3 V SW to GND -0.3 VIN to GND Lead Soldering Temperature (10 seconds) Junction Temperature Storage Temperature -55 Thermal Resistance (ΘJA) Electrostatic Discharge Protection (ESD) Level (Note 2) HBM 2 CDM 1 Min. Typ. 35 V 300 °C 150 °C 150 °C 210 °C/W KV Recommended Operating Conditions Parameter Max. Unit Input Voltage 1.8 5.5 V Output Voltage VIN 30 V Operating Ambient Temperature -40 Output Capacitance Rated at the Required Output (Note 3) 0.1 25 85 °C µF Notes: 1. Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Absolute maximum ratings apply individually only, not in combination. 2. Using EIA/JESD22A114B (Human Body Model) and EIA/JESD22C101-A (Charge Device Model). 3. This load capacitance value is required for the loop stability. Tolerance, temperature variation, and voltage dependency of the capacitance must be considered. Typically a 0.47µF ceramic capacitor is required to achieve specified value at V OUT = 30V. 3 FAN5330 Rev. 1.0.1 www.fairchildsemi.com FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch Absolute Maximum Ratings (Note1) Unless otherwise noted, VIN = 3.6V, ILED = 20mA, TA = -40°C to 85°C, Typical values are at TA = 25°C, Test Circuit, Figure 3. Parameter Conditions Min. Typ. Max. Units 121 mV Feedback Voltage 99 110 Switch Current Limit VIN = 3.2V 1.1 1.5 Load Current Capability VOUT ≤ 20V VIN = 3.2V 35 Switch On-resistance VIN = 5V 0.6 Ω VIN = 3.6V 0.7 Ω Quiescent Current VSHDN = 3.6V, No Switching 0.6 OFF Mode Current VSHDN = 0V 0.1 Shutdown Threshold Device ON Shutdown Pin Bias Current VSHDN = 0V or VSHDN = 5.5V Feedback Pin Bias Current 2.7V < VIN < 5.5V, VOUT ≤ 20V Maximum Duty Cycle µA V 0.5 V 1 300 nA 1 300 nA 1.75 MHz 1 µA 0.3 Switching Frequency Switch Leakage Current mA 3 1.5 Device OFF Feedback Voltage Line Regulation A mA 1.25 1.5 87 93 No Switching, VIN = 5.5V % % OVP 15 % Thermal Shutdown Temperature 150 °C Test Circuit BAT54 L VIN 10µH CIN COUT 1µF 10µF 5 SW FAN5330 VIN 4 ON OFF VOUT SHDN ILED 1 Electronic Load FB GND 3 R 2 Figure 3. Test Circuit 4 FAN5330 Rev. 1.0.1 www.fairchildsemi.com FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch Electrical Characteristics TA = 25°C, CIN = 4.7µF, COUT = 0.47µF, L = 10µH, unless otherwise noted. LED Current vs Temperature SW Frequency vs. Temperature 2.0 10.8 VIN = 5.5V VIN = 2.2V VOUT = 15V SW Frequency (MHz) LED Current (mA) 10.6 10.4 10.2 VIN = 3.6V 10.0 9.8 9.6 -40 -20 0 20 40 60 80 VOUT = 15V 1.8 VIN = 3.6V VIN = 5.5V 1.6 1.4 VIN = 2.2V 1.2 -40 -20 0 20 40 60 80 Temperature (°C) Start-Up Response Load Current vs. Input Voltage 25 L = 10µH CIN = 10µF COUT = 1µF VIN = 2.7V Output Voltage (5V/div) 15 10 Battery Current (0.5A/div) Load Current (mA) VOUT = 15V 20 5 0 3 4 5 EN Voltage (5V/div) 2 Input Voltage (V) Time (100µs/div) Efficiency vs. Input Voltage Efficiency vs. Input Voltage 100 100 VOUT = 9V VOUT = 15V 90 Efficiency (%) Efficiency (%) 90 80 ILED = 35mA 70 60 ILED = 30mA ILE D = 10mA ILED = 20mA 80 ILED = 35mA 70 ILED = 30mA ILED = 20mA 60 ILED = 10mA 50 2.0 2.5 3.0 3.5 4.0 4.5 5.0 50 5.5 2.0 Input Voltage (V) 5 FAN5330 Rev. 1.0.1 2.5 3.0 3.5 4.0 4.5 Input Voltage (V) 5.0 5.5 www.fairchildsemi.com FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch Typical Performance Characteristics VIN 5 SHDN 4 Shutdown Circuitry FB SW 1 +Over Voltage - Comp 1.15 x VREF Thermal Shutdown R - FB 3 Error Amp + Reference Σ + Comp - R Ramp Generator Q R Current Limit Comparator - n Driver S + Oscillator + Amp - 30mΩ 2 GND Figure 4. Block Diagram Circuit Description Over-Voltage Protection The FAN5330 is a pulse-width modulated (PWM) current-mode boost converter. The FAN5330 improves the performance of battery powered equipment by significantly minimizing the spectral distribution of noise at the input caused by the switching action of the regulator. In order to facilitate effective noise filtering, the switching frequency was chosen to be high, 1.5MHz. The device architecture is that of a current mode controller with an internal sense resistor connected in series with the N-channel switch. The voltage at the feedback pin tracks the output voltage at the cathode of the external Schottky diode (shown in the test circuit). The error amplifier amplifies the difference between the feedback voltage and the internal bandgap reference. The amplified error voltage serves as a reference voltage to the PWM comparator. The inverting input of the PWM comparator consists of the sum of two components: the amplified control signal received from the 30mΩ current sense resistor and the ramp generator voltage derived from the oscillator. The oscillator sets the latch, and the latch turns on the FET switch. Under normal operating conditions, the PWM comparator resets the latch and turns off the FET, thus terminating the pulse. Since the comparator input contains information about the output voltage and the control loop is arranged to form a negative feedback loop, the value of the peak inductor current will be adjusted to maintain regulation. The voltage on the feedback pin is sensed by an OVP Comparator. When the feedback voltage is 15% higher than the nominal voltage, the OVP Comparator stops switching of the power transistor, thus preventing the output voltage from going higher. Every time the latch is reset, the FET is turned off and the current flow through the switch is terminated. The latch can be reset by other events as well. Over-current condition is monitored by the current limit comparator which resets the latch and turns off the switch instantaneously within each clock cycle. The internal reference (VREF) is 110mV (Typical). The output current is set by a resistor divider R connected between FB pin and ground. The output current is given by Open-circuit protection As in any current regulator, if the feedback loop is open, the output voltage increases until it is limited by some additional external circuitry. In the particular case of the FAN5330, the output voltage is limited by the switching transistor breakdown at around 45V, typically (assuming that COUT and the Schottky diode rating voltage are higher). Since at such high output voltage the output current is inherently limited by the discontinuous conduction mode, in most cases, the switching transistor enters non-destructive breakdown and the IC survives. However, to ensure 100% protection for LED disconnection, we recommend limiting VOUT with an external Zener diode or stopping the boost switching with an external voltage supervisory circuit. Applications Information Setting the Output Current V REF I LED = -------------R 6 FAN5330 Rev. 1.0.1 www.fairchildsemi.com FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch Block Diagram Brightness Control The inductor parameters directly related to device performances are saturation current and dc resistance. The FAN5330 operates with a typical inductor value of 10µH. The lower the dc resistance, the higher the efficiency. Usually a trade-off between inductor size, cost and overall efficiency is needed to make the optimum choice. 1. Dimming Using PWM Logic Signal A PWM signal applied to SHDN Table 5 on page 7 can control the LED’s brightness in direct dependence with the duty cycle. The maximum frequency should not exceed 1kHz to ensure a linear dependence of the LED’s average current. The amplitude of the PWM signal should be suitable to turn the FAN5333 ON and OFF. The inductor saturation current should be rated around 1.5A, which is the threshold of the internal current limit circuit. This limit is reached only during the start-up and with heavy load condition; when this event occurs the converter can shift over in discontinuous conduction mode due to the automatic turn-off of the switching transistor, resulting in higher ripple and reduced efficiency. Alternatively, a PWM logic signal can be used to switch a FET ON/OFF to change the resistance that sets the LED’s current Table 6 on page 7. Adjusting the duty cycle from 0% to 100% results in varying the LED’s current between IMIN and IMAX. Where Some recommended inductors are suggested in the table below: Inductor Value V FB V FB I MIN = ------------- and I MAX = -------------------------------R MIN R MIN R SET Comment Vendor Part Number 10µH TDK SLF6025&-100M1R0 10µH MURATA LQH66SN100M01C Highest Efficiency 10µH COOPER SD414-100 Small Size FAN5330 SHDN Table 1: Recommended Inductors Capacitors Selection Figure 5. Dimming Using a PWM Signal For best performance, low ESR input and output capacitors are required. Ceramic capacitors of CIN = 4.7µF and COUT = 0.47µF placed close to the IC pins, are required for optimum performance. The capacitances (COUT) may be reduced to 0.1µF, if higher ripple is acceptable. The output capacitor voltage rating should be according to the VOUT setting. Some capacitors are suggested in the table below Capacitor Value Vendor Part Number 0.47µF Panasonic ECJ-3YB1E474K 4.7µF Murata GRM21BR61A475K FAN5330 FB RSET RMIN Figure 6. Dimming Using a PWM Logic Signal 2. Dimming Using DC Voltage An external adjustable DC voltage Table 7 on page 7 between 0V to 2V can control the LED’s current from 15mA to 0mA, respectively. Table 2: Recommended Capacitors Diode Selection The external diode used for rectification is usually a Schottky diode. Its average forward current and reverse voltage maximum ratings should exceed the load current and the voltage at the output of the converter respectively. A barrier Schottky diode such as BAT54 is preferred, due to its lower reverse current over the temperature range. FAN5330 FB VDC 5Ω Care should be taken to avoid any short circuit of VOUT to GND, even with the IC disabled, since the diode can be instantly damaged by the excessive current. 90KΩ Figure 7. Dimming Using DC Voltage 7 FAN5330 Rev. 1.0.1 1.6KΩ www.fairchildsemi.com FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch Inductor Selection Thermal Shutdown This method allows the use of a greater than 1kHz PWM frequency signal with minimum impact on the battery ripple. The filtered PWM signal Table 8 on page 8 acts as an adjustable DC voltage as long as its frequency is significantly higher than the corner frequency of the RC low pass filter. When the die temperature exceeds 150°C, a reset occurs and will remain in effect until the die cools to 130°C, at that time the circuit will be allowed to restart. PCB Layout Recommendations The inherently high peak currents and switching frequency of power supplies require careful PCB layout design. Therefore, use wide traces for high current paths and place the input capacitor, the inductor, and the output capacitor as close as possible to the integrated circuit terminals. The FB pin connection should be routed away from the inductor proximity to prevent RF coupling. A PCB with at least one ground plane connected to pin 2 of the IC is recommended. This ground plane acts as an electromagnetic shield to reduce EMI and parasitic coupling between components. FAN5330 FB 20KΩ 5Ω 15KΩ 1.6KΩ 0.1µF Figure 8. Dimming Using Filtered PWM Signal 8 FAN5330 Rev. 1.0.1 www.fairchildsemi.com FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch 3. Dimming Using Filtered PWM Signal FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch Mechanical Dimensions 5-Lead SOT-23 B L c e H α E e1 D A A1 Symbol Inches Millimeters Min Max Min Max A .035 .057 .90 1.45 A1 .000 .006 .00 .15 B .008 .020 .20 .50 c .003 .010 .08 .25 D .106 .122 2.70 3.10 E .059 .071 1.50 e .037 BSC e1 Notes 1.80 .95 BSC .075 BSC 1.90 BSC H .087 .126 2.20 3.20 L .004 .024 .10 .60 α 0º 10º 0º 10º Ordering Information Product Number Package Type Order Code FAN5330 5-Lead SOT23 FAN5330SX 9 FAN5330 Rev. 1.0.1 www.fairchildsemi.com The following are registered and unregistered trademarks Fairchild Semiconductor owns or is authorized to use and is not intended to be an exhaustive list of all such trademarks. ACEx™ FAST ActiveArray™ FASTr™ Bottomless™ FPS™ Build it Now™ FRFET™ CoolFET™ GlobalOptoisolator™ CROSSVOLT™ GTO™ DOME™ HiSeC™ EcoSPARK™ I2C™ E2CMOS™ i-Lo™ EnSigna™ ImpliedDisconnect™ FACT™ IntelliMAX™ FACT Quiet Series™ Across the board. Around the world.™ The Power Franchise Programmable Active Droop™ ISOPLANAR™ LittleFET™ MICROCOUPLER™ MicroFET™ MicroPak™ MICROWIRE™ MSX™ MSXPro™ OCX™ OCXPro™ OPTOLOGIC OPTOPLANAR™ PACMAN™ POP™ Power247™ PowerEdge™ PowerSaver™ PowerTrench QFET QS™ QT Optoelectronics™ Quiet Series™ RapidConfigure™ RapidConnect™ µSerDes™ SILENT SWITCHER SMART START™ SPM™ Stealth™ SuperFET™ SuperSOT™-3 SuperSOT™-6 SuperSOT™-8 SyncFET™ TinyLogic TINYOPTO™ TruTranslation™ UHC™ UltraFET UniFET™ VCX™ Wire™ DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. 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PRODUCT STATUS DEFINITIONS Definition of Terms Datasheet Identification Product Status Definition Advance Information Formative or In Design This datasheet contains the design specifications for product development. Specifications may change in any manner without notice. Preliminary First Production This datasheet contains preliminary data, and supplementary data will be published at a later date. Fairchild Semiconductor reserves the right to make changes at any time without notice in order to improve design. No Identification Needed Full Production This datasheet contains final specifications. Fairchild Semiconductor reserves the right to make changes at any time without notice in order to improve design. Obsolete Not In Production This datasheet contains specifications on a product that has been discontinued by Fairchild semiconductor. The datasheet is printed for reference information only. Rev. I16 10 FAN5330 Rev. 1.0.1 www.fairchildsemi.com FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch TRADEMARKS