FAN5343 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface Features Description Asynchronous Boost Converter − VOUT up to 24V Internal Schottky Diode Up to 500mW Output Power 2.7V to 5.5V Input Voltage Range Single-Wire Digital Control Interface to Set LED Brightness Levels − 32 Linear Steps Fixed Switching Frequency: 1.2MHz Soft-Start Capability Input Under-Voltage Lockout (UVLO) Output Over-Voltage Protection (OVP) Short-Circuit Detection Thermal Shutdown Protection (TSD) Small 6-Lead 2.0 x 2.0 x 0.55mm UMLP Package The FAN5343 is an asynchronous constant-current LED driver capable of efficiently delivering up to 500mW to a string of six (6) LEDs in series. Optimized for small form factor applications, the 1.2MHz fixed switching frequency allows the use of small chip inductors and capacitors. The FAN5343 uses a single-wire digital control interface to program the brightness levels of the LEDs in 32 linear steps by applying digital pulses. For safety, the device features integrated over-voltage, overcurrent, short circuit detection, and thermal shutdown protection. In addition, input under-voltage lockout protection is triggered if the battery voltage is too low. The FAN5343 is available in a very low profile, small form factor 2mm x 2mm x 0.55mm 6-lead UMLP package that is green and RoHS compliant. Applications Cellular Mobile Handsets Mobile Internet Devices Portable Media Players PDA, DSC, MP3 Players Ordering Information Part Number Temperature Range Package Packing FAN5343UMPX -40 to 85 °C 6-Lead, Ultra-Thin Molded Leadless (UMLP) Package Tape and Reel © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 www.fairchildsemi.com FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface August 2010 FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface Typical Application Diagram Figure 1. Typical Application Block Diagram Figure 2. Block Diagram © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 www.fairchildsemi.com 2 VOUT 1 VIN 2 EN 3 P1 GND 6 GND 5 SW 4 FB Figure 3. UMLP6 Package (Top View) Pin Definitions Pin # Name Description 1 VOUT Boost Output Voltage. Output of the boost regulator. Connect the LEDs to this pin. Connect COUT to GND. 2 VIN Input Voltage. Connect to power source and decouple with CIN to GND. 3 EN Enable Brightness Control. Program dimming levels by driving this pin with digital pulses. 4 FB Voltage Feedback. The boost regulator regulates this pin to 0.25V to control the LED string current. Tie this pin to a current setting resistor (RSET) between GND and the cathode of the LED string. 5 SW Switching Node. Tie inductor L1 from the VIN to SW pin. 6 GND Ground. Tie directly to a GND plane. © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 www.fairchildsemi.com 3 FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface Pin Configuration Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. Symbol Min. Max. Units Voltage on VIN Pin –0.3 6.0 V Voltage on FB and EN Pins –0.3 VIN + 0.3 V VSW Voltage on SW Pin –0.3 25 V VOUT Voltage on VOUT Pin –0.3 25 V VIN VFB, VEN ESD TJ TSTG TL Parameter Electrostatic Discharge Protection Level Human Body Model per JESD22-A114 3.3 Charged Device Model per JESD22-C101 2.0 kV Junction Temperature –40 Storage Temperature –65 Lead Soldering Temperature, 10 Seconds +150 °C +150 °C +260 °C Recommended Operating Conditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to absolute maximum ratings. Symbol VIN Parameter Conditions VIN Supply Voltage (1) VOUT VOUT Voltage IOUT VOUT Load Current 500mW Maximum Output Power Min. Max. Units 2.7 5.5 V 6.2 24.0 V 5 25 mA TA Ambient Temperature –40 +85 °C TJ Junction Temperature –40 +125 °C Note: 1. Application should guarantee that minimum and maximum duty-cycle should fall between 20-85% to meet the specified range. Thermal Properties Junction-to-ambient thermal resistance is a function of application and board layout. This data is measured with four-layer 2s2p boards in accordance to JEDEC standard JESD51. Special attention must be paid not to exceed junction temperature TJ(max) at a given ambient temperate TA. Symbol θJA Parameter Junction-to-Ambient Thermal Resistance © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 Typical Units 70 °C/W www.fairchildsemi.com 4 FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface Absolute Maximum Ratings VIN = 2.7V to 5.5V and TA = -40°C to +85°C unless otherwise noted. Typical values are at TA = 25°C and VIN = 3.6V. Symbol Parameter Conditions Min. Typ. Max. Units 0.30 0.75 μA Power Supplies ISD Shutdown Supply Current EN = GND, VIN = 3.6V VUVLO Under-Voltage Lockout Threshold VUVHYST Under-Voltage Lockout Hysteresis VIN Rising 2.10 2.35 2.60 V VIN Falling 1.90 2.15 2.40 V 250 mV EN: Enable Pin VIH HIGH-Level Input Voltage VIL LOW-Level Input Voltage 1.2 200 V 300 0.4 V 400 kΩ 300.0 µs REN EN Pull-Down Resistance tLO EN Low Time for Dimming VIN = 3.6V; See Figure 14 0.5 tHI Time Delay Between Steps VIN = 3.6V; See Figure 14 0.5 µs TSD EN Low, Shutdown Pulse Width VIN = 3.6V; from Falling Edge of EN 1 ms Feedback and Reference VFB Feedback Voltage ILED = 20mA from -40°C to +85°C, 2.7V ≤ VIN ≤ 5.5V IFB Feedback Input Current 237 250 263 mV VFB = 250mV 0.1 1.0 μA VIN = 3.6V, ISW = 100mA 600 VIN = 2.7V, ISW = 100mA 650 SW Node Leakage EN = 0, VIN = VSW = VOUT = 5.5V, VLED = 0 0.1 Boost Switch Peak Current Limit VIN = 3.6V 750 Power Outputs RDS(ON)_Q1 Boost Switch On-Resistance ISW(OFF) ILIM-PK (2) mΩ 2.0 μA mA Oscillator fSW Boost Regulator Switching Frequency 1.0 1.2 22.5 24.5 1.4 MHz Output and Protection VOVP Boost Output Over-Voltage Protection OVP Hysteresis V 1.0 VTLSC VOUT Short Circuit Detection Threshold VOUT Falling VIN – 1.4 V VTHSC VOUT Short Circuit Detection Threshold VOUT Rising VIN – 1.2 V (3,4) DMAX Maximum Boost Duty Cycle DMIN Minimum Boost Duty Cycle 85 % TTSD Thermal Shutdown 150 °C THYS Thermal Shutdown Hysteresis 35 °C (3,4) 20 % Notes: 2. SW leakage current includes the leakage current of two internal switches; SW to GND and SW to VOUT. 3. Not tested in production, but guaranteed by design 4. Application should guarantee that minimum and maximum duty cycle fall between 20-85% to meet the specified range. © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 www.fairchildsemi.com 5 FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface Electrical Specifications VIN = 3.6V, TA = 25°C, ILED = 25mA, L = 10µH, COUT = 1.0µF 6 LEDs L = 10µH COUT = 1.0µF 6 LEDs L = 10µH COUT = 1.0µF ILED = 25mA Figure 4. 6 LEDs: Efficiency vs. LED Current vs. Input Voltage Figure 5. Frequency vs. Input Voltage vs. Temperature 0.8 Delta Feedback Voltage (mV) 5 LEDs L = 10µH COUT = 1.0µF 0.6 0.4 0.2 0 -0.2 -40°C +25°C -0.4 +85°C -0.6 2.7 3 3.3 3.6 3.9 4.2 Input Voltage (V) Figure 6. 5 LEDs: Efficiency vs. LED Current vs. Input Voltage Figure 7. Delta of VFB Over Input Voltage and Temperature for 6 LEDs with L=10µH and COUT=1.0µF 6 LEDs L = 10µH COUT = 1.0µF ILED = 25mA 6 LEDs L = 10µH COUT = 1.0µF ILED = 25mA Figure 8. Efficiency vs. Input Voltage vs. Temperature © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 Figure 9. Over-Voltage Protection vs. Input Voltage www.fairchildsemi.com 6 FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface Typical Characteristics VIN = 3.6V, TA = 25°C, ILED = 25mA, L = 10µH, COUT = 1.0µF Figure 10. Line Transient Response for 6 LEDs Figure 11. Dimming Operation of FAN5343 Figure 12. Startup Waveform for Switch Voltage, Inductor Current, VFB, and EN for 6 LEDs Figure 13. Steady-State Waveform for VOUT, Switch Voltage, and Inductor Current for 6 LEDs © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 www.fairchildsemi.com 7 FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface Typical Characteristics Overview Digital Dimming Control The FAN5343 is an inductive current-mode boost serial LED driver that achieves LED current regulation by maintaining 0.25V across the RSET resistor. The current through the LED string (ILED) is therefore given by: The FAN5343 starts driving the LEDs at the maximum brightness level. After startup, the control logic is ready to accept programming pulses to decrease the brightness level by the positive edges applied to the EN pin. Figure 14 illustrates the digital pulse dimming control for the FAN5343. ILED = 0.25 R SET (1) The voltage VOUT is determined by the the sum of the forward voltages across each LED, plus the voltage across RSET, which is always 250mV. Over-Current and Short-Circuit Detection The boost regulator employs a cycle-by-cycle peak inductor current limit of ~750mA to protect the switching elements and the device itself from being damaged. Over-Voltage / Open-Circuit Protection UVLO and Soft-Start If EN has been LOW for more than 1ms, the IC may initiate a “cold start” soft-start cycle when EN rises, provided VIN is above the UVLO threshold. Digital Interface The FAN5343 implements a single-wire digital interface to program the LED brightness to one of thirty two (32) levels spaced in linear steps. With this single-wire solution, the FAN5343 does not require the system processor to constantly supply a signal to drive the LEDs. If the LED string is open circuit, FB remains at 0V and the output voltage continues to increase in the absence of an Over-Voltage Protection (OVP) circuit. The FAN5343’s OVP circuit disables the boost regulator when VOUT exceeds 24.5V and keeps the regulator off until VOUT drops below 22.5V. Thermal Shutdown When the die temperature exceeds 150°C, a reset occurs and remains in effect until the die cools to 125°C; at which time, the circuit is allowed to begin the soft-start sequence. Figure 14. Digital Pulse-Dimming Control Diagram © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 www.fairchildsemi.com 8 FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface Functional Description Inductor and Output Capacitor Selection Table 1. # of LEDs 5, 6 Recommended External Components L 10.0µH Part Number Manufacturer Min. COUT LQH43MN100K03 Murata NLCV32T-100K-PFR TDK VLF3010AT-100MR49-1 TDK 1.00µF Part Number Manufacturer UMK212BJ105KG Taiyo Yuden Component Placement and PCB Recomendations Figure 15. Recommended Component Placement PCB Recommendations Input Capacitance In a typical application, the input and output capacitors should be placed as close to the IC as possible; no additional capacitance is needed to ensure proper functionality. However, in a testing environment, where the FAN5343 is typically powered by a power supply with relatively long cables, an additional input capacitor (10µF) may be needed to ensure stable functioning. This capacitor should be placed close to where the power supply cables attach to the FAN5343 evaluation board. © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 The inductor can be connected to VIN with vias through another layer if needed. The feedback pin should be connected back to the IC on a sub-layer. www.fairchildsemi.com 9 FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface Application Information 0.10 C A 2.0 2X B 1.45 2.0 PIN1 IDENT (0.25) 0.10 C 0.80 1.80 2X 6X 0.50 TOP VIEW 6X 0.35 0.55 MAX 0.65 A 0.10 C RECOMMENDED LAND PATTERN (0.15) 0.08 C 0.05 0.00 C SEATING PLANE SIDE VIEW NOTES: A. PACKAGE CONFORMS TO JEDEC MO-229 EXCEPT WHERE NOTED. 1.35 1.45 PIN1 IDENT 1 3 B. DIMENSIONS ARE IN MILLIMETERS. 6X 0.35 0.25 0.10 C A B 0.05 C C. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994. 0.70 0.80 6 D. LANDPATTERN RECOMMENDATION IS BASED ON FSC DESIGN ONLY. E. DRAWING FILENAME: MKT-UMLP06Erev2. 4 0.65 0.35 6X 0.25 BOTTOM VIEW Figure 16. 6-Lead, Ultra-Thin Molded Leadless Package (UMLP) Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4 www.fairchildsemi.com 10 FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface Physical Dimensions FAN5343 — 6-LED Series Boost LED Driver with Integrated Schottky Diode and Single-Wired Digital Interface 11 www.fairchildsemi.com © 2009 Fairchild Semiconductor Corporation FAN5343 • Rev. 1.0.4