Product Change Notices PCN No.:20081201 Date: 12/17/2008 This is to inform you that AME5144 datasheet has been changed from Rev. C.01 to Rev. D.01. This notification is for your information and concurrence. If you require data or samples to qualify this change, please contact AME, Inc. within 30 days of receipt of this notification. If we do not receive any response from you within 30 calendar days from the date of this notification, we will consider that you have accepted this PCN. If you have any questions concerning this change, please contact: PCN Originator: Name: Sean Huang Email: sean_huang @ame.com.tw Expected 1st Device Shipment Date: 12/20/2008 Earliest Year/Work Week of Changed Product: 0842 Description of Change : 1. Add Load Current Calculation on Page 10. 2. Add Duty Cycle Calculation and description on Page 10. 3. Change Soft-Start And Shutdown Response Curve on Page 11. 4. Change test condition and limits of Electrical Specifications as following: Parameter Adjustable Output Range Switch Leakage Current Symbol Test Condition Min VOUT Note 1 VIN-VD ISW,LK VSW=36Æ37V,CTRL=GND Typ 0.01 Max Units 36Æ37 V 5 uA Note 1: VD is the forward-voltage drop of the Schottky diode in Typical Application. Reason for Change: 1. For customer application. 2. For customer application. 3. Correct the waveform of production version. 4. Correct error to comply with AME5144 specification. QPM018B-B AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 n General Description n Features The AME5144 is an efficient driver for up to ten white LED applications. They are ideal for large LCD backlight displays in Cell Phone, PDAs, and other handheld devices. The AME5144 is switch-mode boost converter with constant LED current, rather than output voltage. The series connection allows the LED currents to be identical for uniform brightness and minimizes the number of trace to the LEDs. The AME5144 drives series-connected LEDs to controlled-current pin which connected a typically 13Ω sense resistor, not an expensive fraction-ohm value. l Up to 10 LEDs at 25mA l 86% Efficiency l 1.7% Current-Regulation Accuracy l Output Overvoltage Protection l Flexible Dimming Control Analog Direct-PWM Internal Filter l 1MHz PWM Switching Frequency Fast 1MHz current-mode PWM operation allows for small input and output capacitors and a small inductor while minimizing ripple on the input supply/battery. Soft-start eliminates inrush current during startup. To control LED brightness, the LED current can be pulsed by applying a single analog/PWM signal with a frequency range from 200Hz to 30KHz for the control pin CTRL. The AME5144 is available in space saving, 8 pin, 3mm x 3mm x 0.75mm DFN package. l 0.1uF Output Capacitor l Soft-Start Eliminates Inrush Current l 2.6V to 5.5V Input Range l 0.3uA Shutdown current l DFN 3mm x 3mm x 0.75mm Package with Exposed Paddle l All AME’ s Lead Free Products Meet RoHS Standards n Applications l Cell Phones and Smart Phones C l PDAs, Palmtops, and Wireless Handhelds l e-Books and Subnotebooks l White LED Display Backlighting ie S - Rev.D.01 1 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 n Typical Application L=22µH Output Up to 37V VIN CIN OUT SW 2.2µF COUT 0.1µF AME5144 IN Analog or PWM Dimming PGND CTRL 200Hz to 30KHz CS GND COMP CCOMP 0.1µF 2 to 10 LEDs RSENSE 13Ω n Function Block Diagram 170mV Comp Shutdown 8.2ms CTRL Bright Control OVLO OUT Gm CS SW Ramp Generator PWM Control Driver PGND GND Oscillator 2 Current Limit UVP IN Rev. D.01 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 n Pin Configuration DFN-8C (3mmx3mmx0.75mm) Top View 8 7 6 5 AME5144-AVAxxx 1. OUT 2. IN 3. CTRL 4. CS AME5144 5. COMP 6. GND 7. PGND 1 2 3 4 8. SW * Die Attach: Conductive Epoxy n Pin Description Pin Number Pin Name 1 OUT 2 IN Pin Description Overvoltage Sense. When OUT is greater than 38.5V(Typ.), the internal nchannel MOSFET turns off until OUT drops below 37V(Min), then the IC reenters soft-start Connect a 0.1uf ceramic capacitor from OUT to ground. In shutdown, VOUT is one diode drop below VIN . C Input Voltage Supply. The input voltage range is 2.6V to 5.5V. Connect a 2.2uF ceramic capacitor from IN to GND. Brightness Control pin. Either an Analog or PWM control signal can be used. ie The PWM signal must be between 200Hz and 30KHz. Varying the voltage from +0.24V to +1.65V adjusts the brightness from dim to 100% brightness, respectively. Any voltage above +1.65V does not increase brightness. Hold CTRL below 100mV to shut down the IC after an 8.2ms delay. 3 CTRL 4 CS Current Sense Feedback input. Connect a resistor from CS to GND to set the LED bias current. The voltage at CS regulates to VCRTL/5 or 0.330V. 5 COMP Compensation input. Connect a 0.1µF Ceramic Capacitor(Ccomp) from COMP to GND. Ccomp stabilizes the converter, controls soft-start and lowpass filters direct PWM dimming at CTRL. Ccomp discharges to 0V through an internal 20KΩ resistor in showdown. 6 GND 7 PGND Power Ground. Connect to PGND and exposed pad directly under the IC. 8 SW Inductor Connection. Connect SW to the node between the inductor and schottky diode. SW is high impedance in shutdown. Rev.D.01 Ground. Connect to PGND and exposed pad directly under the IC. 3 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 n Ordering Information AME5144 - x x x xxx Output Voltage Number of Pins Package Type Pin Configuration & Special Feature Pin Configuration & Special Feature A (DFN-8C) 1. OUT 2. IN 3. CTRL 4. CS 5. COMP 6. GND 7. PGND 8. SW Package Type Number of Pins V: DFN A: 8 Output Voltage ADJ: Adjustable n Available Options Part Number Marking* Output Voltage Package Operating Ambient Temperature Range AME5144-AVAADJ A5144 AMYMXX ADJ DFN-8C -40OC to +85OC Note: 1. The first 2 places represent product code. It is assigned by AME such as AM. 2. Y is year code and is the last number of a year. Such as the year code of 2008 is 8. 3. A bar on top of first letter represents Green Part such as A5144. 4. The last 3 places MXX represent Marking Code. It contains M as date code in "month", XX as LN code and that is for AME internal use only. Please refer to date code rule section for detail information. 5. Please consult AME sales office or authorized Rep./Distributor for the availability of output voltage and package type. 4 Rev. D.01 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 n Absolute Maximum Ratings Parameter Maximum Unit -0.3 to 6.0 V -0.3 to (V IN + 0.3) V SW, OUT to GND -0.3 to 40 V PGND to GND -0.3 to 0.3 V VIN , to GND CTRL, CS, COMP, to GND B* ESD Classification Caution: Stress above the listed absolute maximum rating may cause permanent damage to the device. * HBM B: 2000V ~ 3999V n Recommended Operating Conditions Parameter Rating Unit Storage Temperature Range -65 to +150 o Ambient Temperature Range -40 to +85 o Junction Temperature Range -40 to +125 o C C C C n Thermal Information Parameter ie Package Die Attach Thermal Resistance* (Junction to Case) Thermal Resistance (Junction to Ambient) DFN-8C Conductive Epoxy Symbol Maximum θJC 17 o C/W θJA 125 o C/W PD 800 Internal Power Dissipation Solder Iron (10 Sec)** 350 Unit mW o C * Measure θJC on backside center of molding compund if IC has no tab. ** MIL-STD-202G 210F Rev.D.01 5 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 n Electrical Specifications VIN = 3V, L=22µH, CIN=2.2µF, COUT=0.1µF, CCOMP=0.1µF, RSENSE =13Ω, TA = 25oC, unless otherwise noted. Parameter Input voltage Symbol Test Condition VIN Typ Max Units 2.6 5.5 V 37 V 2.55 V Adjustable Output Range VOUT Note 1 VIN -VD Input Undervoltage Locked UVP Rising edge 2.10 Input Undervoltage Locked Hysteresis UVP Hysteresis 2.38 30 mV Quiescent Current IQ No Switching, VCS=0.5V 0.5 0.7 mA Shutdown Current ISHDN CTRL=GND, VOUT=VIN 0.3 2 µA Over Voltage Protection OVP VOUT Rising 38.5 40 V Over Voltage Protection Hysteresis OVP,HYST OUT Input Bias Current IB,OUT VCTRL=1.5V, VCS CS Input Bias Current ICS VCS=VCTRL/5 VCS(MAX) VCTRL=3V CTRL Input Resistance VIN=2.6V to 5.5V RCTRL VDM CTRL Dual-Mode Hysteresis VDM Hysteresis V 20 35 0.01 1 µA 0.290 0.300 0.310 V 0.01 1 µA 330 347 mV 310 VCTRL(MAX) CTRL Dual-Mode Threshold CTRL Shutdown Enable Delay 9 OUT=IN, CTRL=GND CTRL to CS Regulation CS Maximum Brightness Clamp Voltage CTRL Voltage for CS Maximum Brightness Clamp 37 2 VOUT=32V, VCTRL>0.24V 6 Min 1.65 VCTRL<=1.5V V 250 500 780 KΩ 100 170 240 mV 5 Note 2 6.0 8.2 mV 10.5 mS Rev. D.01 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 n Electrical Specifications (contd.) Parameter Symbol Test Condition Min Typ CS to Comp Transconductance Gm VCOMP=1.5V 32 50 COMP Input Resistance to Ground In shutdown, UVLO or OVLO Switch Frequency fOSC Minimum Duty Cycle DMIN Max Units 82 20 0.75 1.0 PWM Mode 12 Pulse Skipping 0 µS KΩ 1.25 MHz % Maximum Duty Cycle DMAX CTRL=IN, CS=GND 94 Switch On-Resistance RDS,ON ISW =190mA 0.8 1.35 Ω Switch Leakage Current ISW,LK VSW =37V, CTRL=GND 0.01 5 µΑ Switch Current Limit ISW,CL Duty Cycle=90% 700 900 mA 500 95 % Note 1: VD is the forward-voltage drop of the Schottky diode in Typical Application. Note 2: Time from CTRL going below the Dual-Mode threshold to IC shutdown. C ie Rev.D.01 7 AME AME5144 n Detailed Description The high efficiency and small size of the AME5144 make them ideally suited to driver up to ten series-connected LEDs. They operate as a boost DC-DC converter that controls output current rather than voltage. A low 300mV current-sense threshold minimized the losses. The AME5144 provide even illumination by sourcing the same output current through each LED, eliminating the need for expensive factory calibration. The fast 1MHz internal oscillator allows for small inductor and small input and output capacitors while minimizing input and output ripple. The single analog control input (CTRL) allows easy adjustment of LED brightness and on/off control. This allows simple logic-level on/off control, analog voltage control, or PWM duty-cycle control of both brightness and shutdown. In shutdown, supply current is reduced to a low 0.3µA (Typ.). A soft-start gradually illuminates the LEDs, eliminating the inrush current during startup. Shutdown The AME5144 enter shutdown when VCTRL is less than 100mV for more than 8.2ms. When shutdown, the supply current is reduced to 0.3µA (Typ.) approximately. The 0.3uA supply current is applied for the voltage-detection circuitry. CCOMP is discharge during shutdown, allowing the device to reinitiate soft-start when enabled. Although the internal n-channel MOSFET does not switch in shutdown, there is still a DC current path between the input and the LEDs through the inductor and Schottky diode. The minimum forward voltage of the LED array must exceed the maximum input voltage to ensure that the LEDs remain off in shutdown. However, with two or more LEDs, the forward voltage is enough to keep leakage current low, less than 1µA (Typ.). Soft-Start The AME5144 attain soft-start by charging CCOMP gradually with a current source. When V COMP rises above 1.25V, the internal MOSFET begins switching at a reduced duty cycle. When VCOMP rises above 2.25V, the duty cycle is at its maximum. See the Typical Operation Characteristics for an example of soft-start operation. 8 High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs Over Voltage Protection OVP is designed to prevent the output voltage from exceeding the maximum switch voltage rating of 38.5V (Typ.). The protection circuitry stops the internal MOSFET from switching. There is a 1.5V hysteresis associated with this circuitry which will cause the output to fluctuate between 38.5V and 37V. Adjusting LED Current Adjusting the output current of the AME5144 changes the brightness of the LEDs. An analog input (CTRL) and the sense-resistor values set the output current. Output current is given by: ILED =VCTRL/(5xRSENSE) The VCTRL voltage range for adjusting output current is 0.24V to 1.65V. To set maximum current, calculate RSENSE when VCTRL is at its maximum as follows: RSENSE=1.65V / (5 x ILED ) Power dissipation in RSENSE is typical less than 10mW, allowing the use of small surface-mount resistor. PWM Dimming Control A. Using DC Signal for CTRL Pin For CTRL, applying a DC signal in the range of 0.24V to 1.65V control the LED current. CTRL can be overdriven; however, applying a CTRL greater than 1.65V does not increased the LED current above the level at 1.65V. B. Using PWM signal forc CTRL pin The CTRL input is used as a digital input allowing LED brightness control with a logic-level PWM signal applied directly to CTRL. The frequency range is from 200Hz to 30KHz, while 0% duty cycle corresponds to minimum current, and 100% duty cycle corresponds to full current. The error amplifier and compensation capacitor form a low pass filter so PWM dimming results in DC current to the LEDs without the need for any additional RC filters. Rev. D.01 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 Capacitor Selection Schottky Diode Selection Ceramic capacitors with X5R, X7R, or better dielectric are recommended for stable operation over the entire operating temperature range. The exact values of input and output capacitors are not critical. The typical value for input capacitor is 2.2µF, and the typical value for output capacitor is 0.1µF. Higher values capacitors can be used to reduce input and output ripple, but at the expense of size and higher cost. CCOMP stabilizes the converter and control soft-start. Connect a 0.1µF capacitor from COMP to GND. Inductor values range from 10µH to 47µH. A 22µH inductor optimizes the efficiency for most applications while maintaining low 12mVp-p input ripple. Inductor with low DCR can be more efficiency. To prevent core saturation, ensure that the inductor-saturation current rating exceeds the peak inductor current for the application. Calculate the peak inductor current with the following formula: VOUT ( MAX ) × I LED( MAX ) 0.9 × VIN ( MIN ) I DIODE( RMS) = I OUT × I PEAK 200mA, 40V Schottky diode SOD-523 or Central Semiconductor CMOSH-4E are recommended for applications. Inductor Selection I PEAK = The high switching frequency of the AME5144 demands a high-speed rectification diode (D1) for optimum efficiency. A Schottky diode is recommended due to its fast recovery time and low forward-voltage drop. Ensure that the diode's average and peak current rating exceed the average output current and peak inductor current. In addition, the diode's reverse breakdown voltage must exceed V OUT. The RMS diode current can be approximated from: + VIN ( MIN ) × 0.9us 2× L Layout Consideration Due to fast switching waveforms and high-current paths, careful PC board layout is required. When laying out a board, minimum trace lengths between the IC and RSENSE, the inductor, the diode, the input capacitor and output capacitor. Keep trace short and wide. Keep noisy traces, such as the SW node trace, away from CS. 22µH, 250mA inductor Murata LQH32CN220K and The input bypass capacitor CIN should be placed as close C to the IC as possible. This will reduce copper trace resisSumida CDRH5D16NP- 220MB are recommended. tance, which effect the input voltage ripple of the IC. The output capacitor, COUT, should also be placed close to the i e IC and connected directly between the OUT and GND pins. PGND and GND should be connected directly to the exposed paddle underneath the IC. The ground connections of CIN and COUT should be as close together as possible. Any copper trace connections with the COUT capacitor can increase the series resistance which directly effects output ripple and efficiency. The current setting resistor, RSENSE, should be kept close to the CS pin to minimize copper trace connections that can inject noise in to the system. The traces from IN to the inductor and from Schottky diode to the LEDs can be longer. Rev.D.01 9 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 Duty Cycle The maximum duty cycle of the switching regulator determines the maximum boost ratio of output-to-input voltage that the converter can attain in mode of operation. The duty cycle for a given boost application is defined as: This applies for continuous mode operation. D= VOUT + VDIODE - V IN VOUT + VDIODE - VSW Calculating Load Current The load current is related to the average inductor current by the relation: ILOAD = IIND (AVG) x (1 - D) Where “ D” is the duty cycle of the application. The switch current can be found by: ISW = IIND (AVG) + 1 /2 (IRIPPLE) Inductor ripple current is dependent on inductance, duty cycle, input voltage and frequency: IRIPPLE = D x (V IN-V SW) / (f x L) Combining all terms, we can develop an expression which allows the maximum available load current to be calculated: ILOAD = ( 1-D ) x ( ISW (max) - 10 D ( VIN-VSW ) ) 2fL Rev. D.01 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 Efficiency vs LED Current Efficiency vs Input Voltage 95 100 3 LEDs 95 6 LEDs 3 LEDs 90 4 LEDs 90 85 Efficiency(%) Efficiency(%) 85 80 75 6 LEDs 70 8 LEDs 65 60 10 LEDs 80 75 8 LEDs 10 LEDs 70 65 60 55 55 50 45 50 2 3 4 5 6 0 5 10 Input Voltage(V) 15 20 25 LED Current(mA) LED Current vs Ambient Temperature LED Current vs Direct-PWM Dimming 26 30 24 25 LED Current(mA) LED Current(mA) 22 20 15 10 20 18 ILED =15mA 16 14 12 5 C 0 0 20 40 60 80 10 8 -40 100 Duty Cycle(%) -20 0 20 40 60 80 100 Temperature(o C) ie Switching Waveforms Soft-Start And Shutdown Response 20mV/div AC-coupled VIN VLX 10V/div VOUT 200mV/div AC-coupled IL 100mA/div 400 ns/div Rev.D.01 VCTRL 2V/div IIN 100mA/div ILED 50mA/div VOUT 10V/div 20ms/div 11 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 Ctrl Step Response Direct-PWM Dimming Response V CTRL 1V/ div VCTRL 2V/div 32kHZ 50% Duty cycle IIN 100mA/div V IN 20mV/div AC -coupled ILED 50mA/div V OUT 500 mV/div AC -coupled VOUT 10V /div I LED 20ms /div 10m A/div 10µs/div VFB vs VIN 310 308 306 TA = -40OC VF B(mV) 304 302 300 298 296 TA =85OC T A=25OC 294 292 290 2.6 3.6 4.6 5.6 VIN(V) 12 Rev. D.01 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 n Date Code Rule Month Code 1: January 7: July 2: February 8: August 3: March 9: September 4: April A: October 5: May B: November 6: June C: December n Tape and Reel Dimension DFN-8C (3mmx3mmx0.75mm) P PIN 1 W AME AME C ie Carrier Tape, Number of Components Per Reel and Reel Size Rev.D.01 Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size DFN-8C (3x3x0.75mm) 12.0±0.1 mm 4.0±0.1 mm 3000pcs 330±1 mm 13 AME High Efficiency, 37V Step-Up Converter for 2 to 10 White LEDs AME5144 n Package Dimension DFN-8C (3mmx3mmx0.75mm) b D e L E E1 PIN #1 TOP VIEW D1 BOTTOM VIEW A G1 G REAR VIEW SYMBOLS 14 MILLIMETERS INCHES MIN MAX MIN MAX A 0.700 0.800 0.028 0.031 D 2.900 3.100 0.114 0.122 E 2.900 3.100 0.114 0.122 e 0.600 0.700 0.024 0.028 D1 2.200 2.400 0.087 0.094 E1 1.400 1.600 0.055 0.063 b 0.200 0.320 0.008 0.013 L 0.375 0.575 0.015 0.023 G 0.153 0.253 0.0060 0.010 G1 0.000 0.050 0.0000 0.002 Rev. D.01 www.ame.com.tw E-Mail: [email protected] Life Support Policy: These products of AME, Inc. are not authorized for use as critical components in life-support devices or systems, without the express written approval of the president of AME, Inc. AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and advises its customers to obtain the latest version of relevant information. AME, Inc. , December 2008 Document: 1241-DS5144-D.01 Corporate Headquarter AME, Inc. 2F, 302 Rui-Guang Road, Nei-Hu District Taipei 114, Taiwan. Tel: 886 2 2627-8687 Fax: 886 2 2659-2989