LM3500TLX-21 National Semiconductor, LM3500TLX-21 Datasheet
LM3500TLX-21
Available stocks
Related parts for LM3500TLX-21
LM3500TLX-21 Summary of contents
Page 1
... In shutdown, the LM3500 completely disconnects the input from output, creating total isolation and preventing any leakage currents from trickling into the LEDs. Typical Application Circuit © 2005 National Semiconductor Corporation Features n Synchronous rectification, high efficiency and no external schottky diode required ...
Page 2
... Connection Diagram Ordering Information Maximum Order Number Output Voltage 16V LM3500TL-16 16V LM3500TLX-16 21V LM3500TL-21 21V LM3500TLX-21 Pin Description/Functions Pin Name A1 AGND OUT GND SHDN AGND(pin A1): Analog ground pin. The analog ground pin should tie directly to the GND pin. ...
Page 3
... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications (LM3500-16)(Note 2) OUT V (LM3500-21)(Note 2) OUT V (Note 2) SW FB, SHDN, and NC Voltages Maximum Junction Temperature Lead Temperature (Note 3) ESD Ratings (Note 4) ...
Page 4
Electrical Characteristics Specifications in standard type face are for T Range −10˚C to +85˚C. Unless otherwise specified V A 21. Symbol Parameter I Switch Leakage Current L (LM3500-16) Switch Leakage Current (LM3500-21) UVP Input Undervoltage Lockout OVP ...
Page 5
... IN OUT Note 3: For more detailed soldering information and specifications, please refer to National Semiconductor Application Note 1112: Micro SMD Wafer Level Chip Scale Package (AN-1112), available at www.national.com. Note 4: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each pin ...
Page 6
Typical Performance Characteristics Switching Quiescent Current LED Efficiency vs LED Current L = Coilcraft DT1608C-223, Efficiency = 100*(P /( LED Efficiency vs LED Current L = Coilcraft DT1608C-223, Efficiency = 100*(P /(3V IN www.national.com Non-Switching ...
Page 7
Typical Performance Characteristics 4 LED Efficiency vs LED Current L = Coilcraft DT1608C-223, Efficiency = 100*(P /( LED Efficiency Coilcraft DT1608C-223, Efficiency = 100*(P /( LED Efficiency Coilcraft ...
Page 8
Typical Performance Characteristics Output Power LM3500- Coilcraft DT1608C-223) Switch Current Limit vs V Switch Current Limit vs Temperature LM3500-16, V OUT www.national.com (Continued) Output Power vs Temperature: LM3500-16 20065784 Switch Current Limit vs Temperature ...
Page 9
Typical Performance Characteristics Switch Current Limit vs Temperature LM3500-21, V =8V OUT Switch Current Limit vs Temperature LM3500-21, V =18V OUT V DC Bias vs V Voltage: LM3500-16 OUT OUT (Continued) Switch Current Limit vs Temperature LM3500-21, V 20065792 Oscillator ...
Page 10
Typical Performance Characteristics FB Voltage vs Temperature NMOS DSON (I = 300mA) SW Typical V Ripple IN LM3500-16, 3 LEDs 22Ω 3.0V LED IN 1) SW, 10V/div 100mA/div, DC ...
Page 11
Typical Performance Characteristics Start-Up: LM3500-21 3 LEDs 22Ω 3.0V LED IN 1) SHDN, 1V/div 100mA/div 10/div, DC OUT T = 200µs/div V = 2.7V CONT Typical V ...
Page 12
Operation The LM3500 utilizes a synchronous Current Mode PWM control scheme to regulate the feedback voltage over almost all load conditions. The DC/DC controller acts as a controlled current source ideal for white LED applications. The LM3500 is internally compensated ...
Page 13
Application Information ADJUSTING LED CURRENT The White LED current is set using the following equation: The LED current can be controlled using a PWM signal on the SHDN pin with frequencies in the range of 100Hz (greater than visible frequency ...
Page 14
Application Information Typical Peak Inductor Currents (mA) # LEDs LED Current (V) series 2 100 134 3 118 138 190 4 142 174 244 5 191 232 319 3.3 ...
Page 15
Application Information FIGURE 2. Evaluation Board Layout (2X Magnification) FIGURE 3. Evaluation Board Layout (2X Magnification) (Continued) Top Layer Bottom Layer (as viewed from the top) 15 20065777 20065778 www.national.com ...
Page 16
Application Information www.national.com (Continued) FIGURE 4. 2 White LED Application FIGURE 5. Multiple 2 LED String Application 16 20065709 20065754 ...
Page 17
Application Information (Continued) FIGURE 6. Multiple 3 LED String Application FIGURE 7. LM3500-21 5 LED Application 17 20065783 20065790 www.national.com ...
Page 18
... BANNED SUBSTANCE COMPLIANCE National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. ...