LM3409MYX National Semiconductor Corporation, LM3409MYX Datasheet
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LM3409MYX
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LM3409MYX Summary of contents
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... Pro- grammable UVLO, low-power shutdown, and thermal shut- down complete the feature set. Typical Application © 2009 National Semiconductor Corporation LM3409 LM3409HV Features ■ 2Ω, 1A Peak MosFET Gate Drive ■ ...
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... Connection Diagram Ordering Information Order Number NSC Package Drawing LM3409MY MUC10A LM3409MYX MUC10A LM3409HVMY MUC10A LM3409HVMYX MUC10A Pin Descriptions Pin(s) Name Description 1 UVLO Input under-voltage lockout 2 IADJ Analog LED current adjust 3 EN Logic level enable / PWM dimming 4 COFF Off-time programming 5 GND ...
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Absolute Maximum Ratings LM3409/09HV (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. VIN, EN, UVLO to GND VIN to VCC, PGATE VIN to PGATE VIN to CSP, CSN ...
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Symbol Parameter V Rising UVLO threshold UVLO-R I UVLO hysteresis current UVLO-HYS ENABLE I EN pin current pin threshold EN- pin hysteresis EN-HYS t EN pin rising delay EN pin falling delay EN-F ...
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Typical Performance Characteristics T = +25° 24V, and characteristics are identical for LM3409 and LM3409HV unless otherwise specified vs. Junction Temperature CST V vs. Junction Temperature ADJ V vs. Junction Temperature OFT V vs. Junction ...
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LM3409 Efficiency vs. Input Voltage V = 17V (5 LEDs LED LM3409 LED Current vs. Input Voltage = 17V (5 LEDs) (Note Normalized Switching Frequency vs. Input Voltage www.national.com LM3409HV Efficiency vs. Input Voltage = ...
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Internal EN Pin PWM Dimming V = 17V (5 LEDs 24V O IN 20kHz 50% EN pin PWM dimming = 48V (Note 42V (12 LEDs 20kHz 50% EN pin PWM dimming (rising ...
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Block Diagram Theory of Operation The LM3409/09HV are P-channel MosFET (PFET) con- trollers for step-down (buck) current regulators which are ideal for driving LED loads. They have wide input voltage range allowing for regulation of a variety of LED loads. ...
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FIGURE 1. Ideal CCM Buck Converter Inductor Current i CONTROLLED OFF-TIME (COFT) ARCHITECTURE The COFT architecture is used by the LM3409/09HV to con- trol combination of peak current detection and a LED one-shot off-timer that ...
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There are three different methods to set the current sense threshold (V ) using the multi-function IADJ pin: CST 1. IADJ pin left open: 5µA internal current source biases the Zener diode and clamps the IADJ pin voltage (V 1.24V ...
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AVERAGE LED CURRENT For a buck converter, the average LED current is simply the average inductor current. FIGURE 5. Sense Voltage v Using the COFT architecture, the peak transistor current ( sensed as shown in Figure 5, which ...
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FIGURE 7. LED Current i PWM DIMMING USING THE EN PIN The enable pin (EN TTL compatible input for PWM dim- ming of the LED. A logic low (below 0.5V will disable the internal driver and ...
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Design Considerations OPERATION NEAR DROPOUT Because the power MosFET is a PFET, the LM3409/09HV can be operated into dropout which occurs when the input voltage is approximately equal to output voltage. Once the input voltage drops below the nominal output ...
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INPUT CAPACITORS Input capacitors are selected using requirements for mini- mum capacitance and RMS ripple current. The PFET current during t is approximately I , therefore the input capacitors ON LED discharge the difference between I LED current (I ) ...
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FIGURE 10. Ideal LED Current i EXTERNAL PARALLEL FET PWM DIMMING Any buck topology LED driver is a good candidate for parallel FET dimming because high slew rates are achievable, due to the fact that no output capacitance is required. ...
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Design Guide TYPICAL APPLICATION SPECIFICATIONS Nominal input voltage Maximum input voltage: V IN-MAX Nominal output voltage (# of LEDs x forward voltage): V LED string dynamic resistance Switching frequency (at nominal V IN Average LED current: ...
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OUTPUT CAPACITANCE A minimum output capacitance (C ) may be necessary to O-MIN reduce Δi below Δi . With the specified Δi LED-PP L-PP the known dynamic resistance ( the LED string, solve for D the required ...
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Design Example #1 EN PIN PWM DIMMING APPLICATION FOR 10 LEDS SPECIFICATIONS f = 525kHz 48V 75V IN IN-MAX V = 35V LED Δi = Δ LED-PP L-PP Δv ...
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AVERAGE LED CURRENT Determine I : L-MAX Assume V = 1.24V and solve for R ADJ SNS The closest 1% tolerance resistor is 0.1 Ω therefore the I is: The chosen component from step 3 is: 4. OUTPUT CAPACITANCE ...
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INPUT UVLO Solve for R : UV2 The closest 1% tolerance resistor is 49.9 kΩ therefore V is: Solve for R : UV1 Design #1 Bill of Materials Qty Part ID 1 LM3409HV IN1 IN2 ...
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Design Example #2 ANALOG DIMMING APPLICATION FOR 4 LEDS SPECIFICATIONS f = 500kHz 24V 42V IN IN-MAX V = 14V LED Δi = 450mA; Δi = 50mA L-PP LED-PP Δv = ...
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AVERAGE LED CURRENT Determine I : L-MAX Assume V = 1.24V and solve for R ADJ The closest 1% tolerance resistor is 0.2 Ω therefore I The chosen component from step 3 is: 4. OUTPUT CAPACITANCE = 2 Ω ...
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INPUT UVLO Solve for R : UV2 The closest 1% tolerance resistor is 49.9 kΩ therefore V is: Solve for R : UV1 Design #2 Bill of Materials Qty Part ID 1 LM3409 2 C IN1 ...
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Applications Information DESIGN #3: EXTERNAL PARALLEL FET PWM DIMMING APPLICATION FOR 10 LEDS Design #3 Bill of Materials Qty Part ID 1 LM3409HV IN1 IN2 OFF ...
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DESIGN #4: SINGLE POTENTIOMETER ANALOG DIMMING APPLICATION FOR 6 LEDS Design #4 Bill of Materials Qty Part ID 1 LM3409 IN1 IN2 OFF ...
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DESIGN #5: 75°C THERMAL FOLDBACK APPLICATION FOR 16 LEDS Design #5 Bill of Materials Qty Part ID 1 LM3409HV IN1 IN2 OFF ...
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DESIGN #6: HIGH CURRENT APPLICATION FOR 4 LEDS Design #6 Bill of Materials Qty Part ID 1 LM3409 2 C IN1 OFF ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 10-Lead Exposed Pad Plastic eMSOP Package NS Package Number MUC10A 28 ...
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Notes 29 www.national.com ...
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