PAM2800 High Power White LED Driver Features n n n n n n n n n General Descriptio n High Efficiency 92% Up to 350mA Constant Source Current Low Quiescent Current: Typ. 65 μ A 0.5 μ A Shutdown Current Short Circuit Protection Open Load LED Protection Thermal Protection Space Saving Package SOT23-5 Pb-Free Package The PAM2800 is a high power white LED driver with 350mA constant rated source current. It features high efficiency and low quiescent current, making it ideal for battery powered applications. Applications n High Power White LED Driver Typical Application Circuit Efficiency vs Supply Voltage 100 IN C IN 1μF 90 R1 R2 1W WLED CO 2.2 μ F Efficiency(%) VOUT PAM2800 EN GND FB 95 VIN 85 80 75 70 65 RS 60 4.8 4.5 4.2 3.9 3.6 3.3 Supply Voltage(V) Figure 1 Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.1 1 PAM2800 High Power White LED Driver Pin Configuration & Marking Information Top View SOT23-5 5 4 EG: I: Y: W: EG I Y W 1 Pin Number 1 2 3 4 5 2 Product Code of PAM2800 Current Code Year Week 3 Name VIN GND EN FB VOUT Function Input Ground Chip Enable (Active High) Feedback Output Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.1 2 PAM2800 High Power White LED Driver Absolute Maximum Ratings These are stress ratings only and functional operation is not implied . Exposure to absolute maximum ratings for prolonged time periods may affect device reliability . All voltages are with respect to ground . Input Voltage..............................................6.6V Output Current........................................350mA Output Pin Voltage...............GND -0.3to V IN+0.3V Lead Soldering Temperature (5sec)...........300 ° C Storage Temperature...................-65 ° C to 150 ° C Recommended Operating Conditions Max. Supply Voltage (for Max. duration of 30 minutes)..............................................6.4V Junction Temperature.................-40 ° C to 125 ° C Ambient Temperature...................-40 ° C to 85 ° C Thermal Information Parameter Symbol Package Maximum Thermal Resistance (Junction to Case) θJC SOT23-5 130 Thermal Resistance (Junction to Ambient) θJA SOT23-5 250 Internal Power Dissipation PD SOT23-5 400 Unit °C/W mW Electrical Characteristic T A=25 ° C , V IN=3.7V, C IN=1 μ F, C O=2.2 μ F, unless otherwise noted . Parameter Symbol Input Voltage VIN Output Current IO Quiescent Current IQ Test Conditions Min Typ Max Unit 5.5 V 300 No Load mA 65 Efficiency 90 90 μA 92 % Over Temperature Shutdown OTS IO=1mA 150 °C Over Temperature Hysteresis OTH IO=1mA 30 °C Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.1 3 PAM2800 High Power White LED Driver Typical Performance Characteristics T A=25°C,C IN=1 μ F,C O=2.2 μ F,R1=62k Ω, R2=33k Ω ,R S=0.22 Ω. Output Current vs Supply Voltage Efficiency vs Supply Voltage 400 100 95 Output Current(mA) 350 Efficiency(%) 90 85 80 75 70 300 250 200 150 65 60 100 4.8 4.5 4.2 3.9 3.6 3.3 4.8 4.5 4.2 3.9 3.6 3.3 Supply Voltage(V) Supply Voltage(V) Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.1 4 PAM2800 High Power White LED Driver Application Information In the typical application (see Figure 1), the LED current will come to constant current level little by little after the device is powered. A 62ΚΩ resistor is recommended for R1, and the value for R2 should be adjusted around 33ΚΩ due to LED forward voltage variation from lot-to-lot or brandto-brand. maximum power dissipation can be calculated by the following formula: P D(MAX) = (T J(MAX)-T A)/θ JA Where T J(MAX) is the maximum operation junction temperature 125°C.TA is the ambient temperature, and θ JA is the thermal resistance from the junction to the ambient. Power Dissipation and Thermal Consideration Thermal protection limits power dissipation in the PA M 2 8 0 0 . W h e n t h e o p e r a t i o n j u n c t i o n temperature exceeds 150°C, the OTP (Over Temperature Protection) starts the thermal shutdown and turns the pass transistor off. The pass transistor resumes operation after the junction temperature drops below 120°C. For example, as θ JA is 250°C/W for SOT-23, based on the standard JEDEC 51-3 for a singlelayer thermal test board, the maximum power dissipation for SOT-23 package at T A=25°C can be calculated by following formula: P D(MAX)= (125°C-25°C)/250=0.4W For continuous operation, the junction temperature should be maintained below 125°C. The power dissipation is defined as: To calculate the junction temperature of the PAM2800 SOT-23 package, if we use input voltage V IN=4V at an output current I O=300mA and the case temperature T A=40°C measured by the thermal couple while operating, the power dissipation is defined as: P D= (V IN-V OUT)*I O+V IN*I GND The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surrounding airflow and temperature difference between junction and ambient. The P D=(4V-2.8V)*300mA+4V*70μA≈360mW Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.1 5 PAM2800 High Power White LED Driver Ordering Information PAM2800 X X X X Shipping Package Number of Pins Package Type Pin Configuration Pin Configuration A Type Package Type Number of Pins A ：SOT-23 B：5 Shipping Package R：Tape & Reel 1. VIN 2. GND 3. EN 4. FB 5. VOUT Part Number Output Current Marking Package Type MOQ PAM2800AABR 350mA EGAYW SOT23-5 3,000 Units/Tape&Reel Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.1 6 PAM2800 High Power White LED Driver Outline Dimension c (REF.) SOT23-5 0.25 D e1 θ L1 (REF.) A2 A1 A E1 E L REF. REF. A A1 A2 c D E E1 L L1 θ b e e1 Min 0 0.70 2.70 2.60 1.40 0º 0.30 Millimeter Nom 1.10MAX 0.05 1.00 0.12REF. 2.90 2.80 1.60 0.45REF. 0.60REF. 5º 0.40 0.95REF. 1.90REF. Max 0.10 1.295 3.10 3.00 1.80 10º 0.50 Power Analog Microelectronics , Inc www.poweranalog.com 09/2008 Rev 1.1 7