LM3508TLEV National Semiconductor, LM3508TLEV Datasheet
LM3508TLEV
Specifications of LM3508TLEV
Related parts for LM3508TLEV
LM3508TLEV Summary of contents
Page 1
... During shutdown, the output is disconnected from the input preventing a leakage current path through the LEDs to ground. The LM3508 is available in a tiny 9-bump chip-scale micro-SMD package. Typical Application Circuit © 2008 National Semiconductor Corporation Features ■ Drives 4 Series White LEDs with up to 30mA ■ ...
Page 2
Connection Diagram 9-Bump (Large) µ-SMD (1.514mm x 1.514mm x 0.6mm) NS Package Number TLA09 Ordering Information Part Number LM3508TL LM3508TLX Pin Descriptions/Functions Pin Name A1 PGND Power Ground Connection Inductor connection and drain connection for both NMOS and ...
Page 3
... Junction to Ambient Thermal Resistance (θ Internally Limited ESD Caution Notice +150°C National Semiconductor recommends that all integrated cir- +300°C cuits be handled with appropriate ESD precautions. Failure to -65°C to +150°C observe proper ESD handling techniques can result in dam- age to the device. ...
Page 4
... J Note 4: 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 5: In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be derated ...
Page 5
LED Efficiency vs I LED = 0.66Ω TDK VLF3012AT-220MR33 Efficiency 20mA) IN LED Peak Current Limit Converter Output Voltage vs LED Current 30004258 Efficiency vs V 30004260 Switching ...
Page 6
Maximum Duty Cycle vs V Quiescent Current vs V (Device Not Switching, V SET Voltage vs DIM Frequency (50% Duty Cycle at DIM) www.national.com IN 30004215 30004216 30004219 6 Quiescent Current ...
Page 7
SET Voltage vs DIM Duty Cycle 30004262 PFET On-Resistance vs Temperature (V = 10.4V 10V) SW OUT Over Voltage Limit Falling) IN OUT NFET On-Resistance Over Voltage Limit 30004225 ...
Page 8
Over-Voltage Protection Function VIN = 3.6V 18.86V OUT Channel 1: V (1V/div) OUT Channel 4: I (500mA/div) IN Time Base: 400µs/div Output Short-Circuit Response V = 3.6V 30mA IN LED Channel 1: V (10V/div) OUT Channel ...
Page 9
Operation The LM3508 utilizes a synchronous step-up current mode PWM controller and a regulated current sink to provide a highly efficient and accurate LED current for white LED bias. The internal synchronous rectifier increases efficiency and eliminates the need for ...
Page 10
DIM Operation DIM is the input to the gate of an internal switch that accepts a logic level PWM waveform and modulates the internal 200mV reference through an internal RC filter. This forces the current source regulation point (V SET ...
Page 11
Once I is set, the LED current can be adjusted from LED_MAX I down applying a logic level PWM signal LED_MAX LED_MIN to DIM. This results in: where D is the duty cycle of the PWM pulse ...
Page 12
Table 2. Recommended Inductor Manufacturers Manufacture L Part r Number TDK 22µ VLF3010 2.6mm×2. H AT-220M 8mm×1m R33 TDK 22µ VLF3012 2.6mm×2. H AT-220M 8mm×1.2 R33 Toko 22u D3313FB 3.3mm×3. H (1036FB- 3mm×1.3 220M) Layout Considerations Proper layout is essential ...
Page 13
Physical Dimensions inches (millimeters) unless otherwise noted For Ordering, Refer to Ordering Information Table X1 = 1.514mm (±0.03mm 1.514mm (±0.03mm 0.6mm (±0.075mm) 9-Bump Micro SMD Package (TL09AAA) NS Package Number TLA09AAA 13 www.national.com ...
Page 14
... For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock Conditioners www.national.com/timing Data Converters www.national.com/adc Displays www.national.com/displays Ethernet www.national.com/ethernet Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www ...