SEMTECH SC4509

SC4509 Highly Integrated Step-Up Converter for White LED Applications in MLPD-W8-2x2 PO POWER MANA WER MANA GEMENT GEMENT Description Features The SC4509 is a highly integrated step-up DC/DC convert- ‹ VIN range: 2.7V — 10V er targeted for white LED backlighting applications. It is ‹ Integrated Schottky diode designed to drive up to Ţ ve LEDs with a wide input voltage ‹ 81% efŢ ciency range of 2.7 to 10 volts. Designed for 20V output voltage, ‹ Requires only 4 external components the SC4509 operates with a constant 1.2MHz PWM fre- ‹ Up to 20V of output voltage quency. To optimize efŢ ciency, the feedback voltage is set ‹ 30mA maximum LED current to only 199mV, minimizing the power loss in the current ‹ Open LED protection (OVP) setting resistor. The product requires only four external ‹ 1.2MHz PWM switching frequency components (CIN, COUT, L and R ), making it ideal for ‹ Low feedback voltage (20OmV typical) SET applications that require low cost and minimal PCB area. ‹ Wide range of PWM dimming ‹ Drives up to 5 LEDs The SC4509 offers current limit and over-voltage protec- ‹ 500mA switch current limit tion (OVP) to safeguard the device under extreme operat- ‹ 220nF output capacitor ing conditions. If the LEDs become disconnected or fail in ‹ Available in 2mm x 2mm x 0.75mm MLPD-W8 and an open state condition, OVP circuitry will be activated to SOT23-6 packages shut down the device. The EN/SS pin allows the device ‹ Packages are fully WEEE and RoHS compliant to be placed in power-down mode, disabling the control circuitry to reduce input current. Applications ‹ Digital Video Cameras ‹ White LED Backlight Driver ‹ OLED Display Driver ‹ Portable Media Players ‹ GPS Receivers ‹ Cellular Phones ‹ PDAs and Handheld Computers Typical Application Circuit Vin L1 Vo 22μH LED1 LED2 C2 0.22μF LED3 U2 VIN 5 LED4 SC4509 EN/SS EN/SS FB 4 3 R1 C1 1μF March 26, 2007 www.semtech.com 1 6 SW 2 GND 1 VOUT SC4509 POWER MANAGEMENT PRELIMINARY Absolute Maximum Rating Exceeding the speciŢ cations below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters speciŢ ed in the Electrical Characteristics section is not implied. Exposure to Absolute Maximum rated conditions for extended periods of time may affect device reliability. Parameter Symbol Maximum Units V Input Supply Voltage -0.3 to 20 V IN SW Voltage V -0.3 to 30 V SW Maximum Output Voltage V 30 V OUT Feedback Voltage V -0.3 to 20 V FB EN/SS Voltage V -0.3 to V + 0.3 V EN/SS IN Maximum Junction Temperature T 125 °C J Storage Temperature Range T -65 to +150 °C STG MLPD-W8 78 Thermal Impedance θ C/W (1) JA Junction to Ambient SOT23-6 165 Lead Temperature (Soldering), 10s (SOT23-6 package only) T 300 °C LEAD Peak IR Flow Temperature, (10-40sec) T 260 °C PKG (2) ESD Rating (Human Body Model) V 2kV ESD Note: 1) Calculated from package in still air, mounted to 3”x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. 2) Tested in accordance to JEDEC standard JESD22-A114B. Electrical Characteristics Unless speciŢ ed: V = V = 3.6V; C = 1μF; C = 0.22μF; L = 22μH; unless otherwise noted, T = +25°C for Typ, -40ºC to 85°C for Min and Max. IN EN/SS IN OUT A Parameter Symbol Conditions Min Typ Max Units Input Voltage V 2.7 10 V IN Quiescent Current I No switching 2.6 3.3 mA Q Feedback Voltage V 182 199 216 mV FB Feedback Pin Bias Current I 35 100 nA QFB Switching Frequency f T =25 °C 1.0 1.2 1.4 MHz OSC A Maximum Output Voltage V 20 V OUT Switch Saturation Voltage V I = 85mA; T =25 °C 160 300 mV CESAT SW A Maximum Duty Cycle D V = GND 90 % MAX FB Switch Current Limit I I = 0; T =25 °C 300 500 700 mA cl LOAD A Switch Leakage Current I V = 5V; V = Open 0.01 5.0 μA LKG SW OUT Shutdown Current I V = GND; V = 3V; V = Open 3 5 μA SHD EN/SS IN OUT (1) PWM Dimming Frequency f 110kHz DIM EN/SS Threshold Low V 50mV IL EN/SS Threshold High V 1.8 V IH © 2007 Semtech Corp. www.semtech.com 2 SC4509 POWER MANAGEMENT Electrical Characteristics (Cont.) Unless speciŢ ed: V = V = 3.6V; C = 1μF; C = 0.22μF; L = 22μH; unless otherwise noted, T = +25°C for Typ, -40ºC to 85°C for Min and Max. IN EN/SS IN OUT A Parameter Symbol Conditions Min Typ Max Units EN/SS Input Low Current I V = GND 1.0 μA IL EN/SS EN/SS Input High Current I 60 100 μA IH Output Over-Voltage Protection OVP 25 30 V Schottky Forward Drop V I = 150mA 0.7 V f_sch D Schottky Leakage Current I V = 25V; V = GND 1.0 4.0 μA f_sch OUT SW Note: 1. Guaranteed by design. © 2007 Semtech Corp. www.semtech.com 3 SC4509 POWER MANAGEMENT PRELIMINARY Pin ConŢ guration Ordering Information Part Numbers Package 1 6 SW VOUT (1)(2) SC4509SKTRT SOT23-6 VIN GND 2 5 (1)(2) SC4509WLTRT MLPD-W8 2mmx2mmx0.75mm EN/SS FB 3 4 (3) SC4509EVB Evaluation Board Notes: 6-pin - SOT23 (1) Only available in tape and reel packaging. A reel contains 3000 devices. (2) Lead-free package. This product is fully WEEE and RoHS compliant. (3) Specify package preference when ordering. EN/SS 1 8 FB TOP VIEW 2 7 VIN GND 3 6 SW GND 4 5 VOUT VOUT T 8-pin - MLPD 2X2 Marking Information TOP MARK BP00 BOTTOM MARK yyww Marking for SOT23, 6 Lead Package: yyww = Datecode (Example: 0652) © 2007 Semtech Corp. www.semtech.com 4 SC4509 POWER MANAGEMENT Pin Descriptions SOT23 MLPD 2X2 Pin Name Function Cathode side of the Schottky output voltage. Connect a 0.22μF capacitor from this 1 4, 5 VOUT pin to ground. 2 2,3 GND Ground connection Feedback input pin. Connect a resistor from this pin to GND to program the LED 31 FB current. Enable pin. When connected to logic high, the converter is enabled. When con- 4 8 EN/SS nected to logic low, the converter is disabled. The LED brightness can be controlled by applying a PWM signal to this pin. 5 7 VIN Input voltage pin. Connect a 1μF capacitor from this pin to GND. 6 6 SW Switching pin - collector of the internal switch. N/A T Exposed pad (bottom); connect to GND directly beneath package. © 2007 Semtech Corp. www.semtech.com 5 SC4509 POWER MANAGEMENT PRELIMINARY Block Diagram SW Internal Schottky VOUT FB 199mV PWM V OVP REF VIN 1.25V Q R S ∑ S GND EN/SS Ramp Generator 1.2MHz Oscillator Theory of Operation The SC4509 is a constant frequency PWM step-up regu- Over-Voltage Protection (OVP) lator IC designed to operate with an input voltage range To prevent the output voltage from exceeding the maxi- mum switch voltage rating (30V), an over-voltage protec- from 2.7V to 10V. tion circuit is integrated. As soon as the output voltage exceeds the OVP threshold, the converter stops switching A maximum output voltage of 20V allows for up to Ţ ve LEDs and the output voltage starts to drop. When the output to be connected in series, providing even illumination by voltage drops back below the OVP threshold, the convert- passing the same output current through each LED. er resumes operation. This sequence will repeat for as long as is necessary. Designed for a low 199mV, the feedback voltage has a direct effect on the converter efŢ ciency. Because the volt- Enable and PWM Dimming age drop across the feedback resistor does not contribute The SC4509 provides the EN/SS pin to serve multiple to the output power (LED brightness), the lower the feed- functions. Its main function is as an enable pin (active back voltage, the higher the efŢ ciency. A 1.2MHz oscillator high). It also can be used to control LED brightness frequency saves board space by reducing external compo- when a PWM signal (up to 10kHz) of varying duty cycle is nent sizes, making the SC4509 ideal for battery-operated applied. A third function acts as a soft-start control. Soft products. start can be implemented by ramping the voltage applied to the pin at startup or by slowly increasing the PMW duty The SC4509 can be conŢ gured as a voltage regulated cycle. boost converter or as a current-regulating boost converter for driving white LEDs. The device is designed to be stable without additional external components in both cases. © 2007 Semtech Corp. www.semtech.com 6 SC4509 POWER MANAGEMENT Applications Information Programming the LED Current Please refer to the Typical Application Circuit on page 1. The LED current is programmed by connecting a resistor (R1) between the FB pin and GND. The LED current in mA is given by the following equation: I = 199/R1 LED where R1 value is in Ohms. Setting the Output Voltage The non-inverting input of the internal error ampliŢ er is tied to a 199mV voltage reference. A simple voltage divider (R1 at the top and R2 at the bottom) sets the converter output voltage. Please refer to the Application Circuit for OLED Panels on the next page. The voltage feedback gain h = 0.199/Vo is related to the divider resistors value as R2 h R1 R2 Once either R1 or R2 is chosen, the other can be calcu- lated for the desired output voltage Vo. Since the number of standard resistance values is limited, the calculated resistance may not be available as a standard value resis- tor. As a result, there will be a set error in the converter output voltage. This non-random error is caused by the feedback voltage divider ratio. It cannot be corrected by the feedback loop. © 2007 Semtech Corp. www.semtech.com 7 SC4509 POWER MANAGEMENT PRELIMINARY Application Circuit for OLED Panels L1 Vo VIN 22μH OLED PANEL R1 U2 5 VIN SC4509 C2 1μF 4 3 EN/SS EN/SS FB R2 C1 1μF © 2007 Semtech Corp. www.semtech.com 8 6 SW 2 GND 1 VOUT SC4509 POWER MANAGEMENT Typical Characteristics EfŢ ciency vs. LED Current EfŢ ciency vs. LED Current V = 2.7V, V = 16V, (4 LED) V = 3.3V, V = 16V, (4 LED) IN OUT IN OUT 80% 85% 75% 80% 75% 70% 70% 65% 65% 60% 60% 55% 55% 50% 50% 45% 45% 40% 40% 35% 35% 30% 30% 0 2 4 6 8 10 1214 1618 2022 0 2 4 6 8 101214 1618 2022 2426 28 3032 I (mA) I (mA) LED LED EfŢ ciency vs. LED Current EfŢ ciency vs. LED Current vs. Input Voltage V = 3.6V, V = 16V, (4 LED) V = 12V, (3 LED) IN OUT OUT 85% 85% 80% 80% 75% 75% 70% 70% VIN = 2.7V 65% 65% VIN = 3.6V 60% 60% 55% 55% 50% 50% 45% 45% 40% 40% 35% 35% 0 2 4 6 8 10 121416 1820 2224 2628 3032 0 5 10 15 20 25 30 35 I (mA) I (mA) LED LED Feedback Voltage vs. Temperature vs. LED Current, Frequency vs. Temperature vs. Input Voltage, V = 16V V = 16V OUT OUT 203.0 1.20 VIN = 2.7V 202.0 1.15 ILED = 20mA 201.0 ILED = 30mA VIN = 3.3V 1.10 200.0 VIN = 3.6V 199.0 1.05 198.0 197.0 1.00 -40 -20 0 20 40 60 80 100 -40 -20 0 20406080 Temperature (Deg. C) Temperature (Deg. C) © 2007 Semtech Corp. www.semtech.com 9 FBK (mV) EfŢ ciency (%) EfŢ ciency (%) Frequency (MHz) EfŢ ciency (%) EfŢ ciency (%) SC4509 POWER MANAGEMENT PRELIMINARY Typical Characteristics (Cont.) EN/SS Input Current vs. EN/SS Voltage vs. Temperature, Output Voltage vs. EN/SS Voltage vs. Temperature, V = 3.6V; V = 16V V = 3.6V; V = 16V IN OUT IN OUT 55.0 16.0 50.0 45.0 14.0 40°C 40.0 25°C 25°C 12.0 35.0 30.0 10.0 85°C 40°C 25.0 8.0 20.0 15.0 6.0 85°C 10.0 4.0 5.0 0.0 2.0 0.00.4 0.81.2 1.62.0 2.42.8 3.2 3.6 4.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 VEN/SS (Volts) VEN/SS (Volts) LED Current vs. PWM Dimming Duty Cycle LED Current vs. PWM Dimming Duty Cycle V = 3.6V; V = 16V; FPWM = 10kHz V = 3.6V; V = 16V; FPWM = 1kHz IN OUT IN OUT 22 22 20 20 18 18 16 14 16 12 14 10 12 8 6 10 4 8 2 0 6 0 1020 3040 50 6070 8090 100 15 25 35 45 55 65 75 85 95 DTY (%) DTY (%) Switch Current Limit vs. Complementary Switch Current Limit vs. Temperature vs. Duty Cycle (1-D) vs. Temperature Complementary Duty Cycle (1-D) 700 800 -40°C 650 700 10% 20% 600 600 550 500 500 0°C 450 60% 400 400 25°C 90% 350 300 40% 85°C 300 200 250 100 200 -40 -20 0 20 40 60 80 100 0 10203040 5060708090 100 (1-D) (%) Temperature (Deg. C) © 2007 Semtech Corp. www.semtech.com 10 Current Limit (mA) I (mA) I (μA) LED EN/SS Current Limit (mA) I (mA) VOUT (V) LED SC4509 POWER MANAGEMENT Typical Characteristics (Cont.) Startup Current Switch Complementary Duty Cycle vs. V = 3.6V; I = 30mA; V = 16V (4 LEDs) Input Voltage vs. LED Current, V = 16V, (4 LED) IN LED OUT OUT 35.0% 30.0% 25.0% ILED = 20mA 20.0% ILED = 30mA 15.0% 10.0% 5.0% 0.0% 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 VIN (V) Switching Waveform V = 3.6V; I = 20mA; V = 16V (4 LEDs) IN LED OUT © 2007 Semtech Corp. www.semtech.com 11 (1-D) (%) SC4509 POWER MANAGEMENT PRELIMINARY Layout Example Top Layer Bottom Layer © 2007 Semtech Corp. www.semtech.com 12 SC4509 POWER MANAGEMENT Outline Drawing - SOT23-6 DIMENSIONS INCHES MILLIMETERS A DIM MIN NOM MAX MIN NOM MAX A - .057 0.90 - 1.45 .035 e1 D - - A1 .000 .006 0.00 0.15 A2 .035 .045 .051 .90 1.15 1.30 N b .010 - .020 0.25 - 0.50 2X E/2 c .003 - .009 0.08 - 0.22 EI E D .110 .114 .122 2.80 2.90 3.10 E1 .060 .063 .069 1.50 1.60 1.75 12 E .110 BSC 2.80 BSC ccc C e .037 BSC 0.95 BSC e1 .075 BSC 1.90 BSC 2X N/2 TIPS L .012 .018 .024 0.30 0.45 0.60 e (.024) (0.60) L1 B N 6 6 01 0° - 10° 0° - 10° aaa .004 0.10 bbb .008 0.20 D ccc .008 0.20 aaa C A2 A SEATING H PLANE A1 C c bxN GAGE PLANE bbb C A-B D 0.25 L 01 (L1) DETAIL A SEE DETAIL A SIDE VIEW NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS AND TO -A- -B- BE DETERMINED AT DATUM PLANE -H- 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. Land Pattern - SOT23-6 X DIMENSIONS DIMENSIONS DIM DIM INCHES INCHES MILLIMETERS MILLIMETERS (.098) (2.50) C C G G .055 1.40 (C) G Z P P .037 0.95 X X .024 0.60 Y Y Y .043 1.10 Z Z .141 3.60 P NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. © 2007 Semtech Corp. www.semtech.com 13 SC4509 POWER MANAGEMENT PRELIMINARY Outline Drawing - MLPD-W8 2x2 B A D DIMENSIONS INCHES MILLIMETERS DIM MIN NOM MAX MIN NOM MAX E A .028 .030 .031 0.70 0.75 0.80 PIN 1 A1 .000 .001 .002 0.00 0.02 0.05 INDICATOR A2 (.008) (0.20) (LASER MARK) b .007 .010 .012 0.18 0.25 0.30 D .075 .079 .083 1.90 2.00 2.10 D1 .059 .063 .067 1.50 1.60 1.70 E .075 .079 .083 1.90 2.00 2.10 E1 .031 .035 .039 0.80 0.90 1.00 A e .020 BSC 0.50 BSC SEATING L .008 .012 .016 0.20 0.40 0.30 PLANE aaa C N 8 8 aaa .003 0.08 A1 A2 C bbb .003 0.08 D1 1 2 LxN E/2 E1 N bxN bbb C A B e e/2 D/2 NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. Land Pattern - MLPD-W8 2x2 H DIMENSIONS R DIM INCHES MILLIMETERS C (.079) (2.00) G .051 1.30 .063 1.60 Z H (C) G K K.035 0.90 P .020 0.50 R .006 0.15 Y X .012 0.30 Y .028 0.70 Z .106 2.70 X P NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 3. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. © 2007 Semtech Corp. www.semtech.com 14 SC4509 POWER MANAGEMENT Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com © 2007 Semtech Corp. www.semtech.com 15