LM3431QMH/NOPB National Semiconductor, LM3431QMH/NOPB Datasheet
LM3431QMH/NOPB
Specifications of LM3431QMH/NOPB
Related parts for LM3431QMH/NOPB
LM3431QMH/NOPB Summary of contents
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... IC and LED array. The enhanced LM3431A features reduced offset voltge for higher accuracy LED current. Typical Application Circuit © 2009 National Semiconductor Corporation LM3431/LM3431A/LM3431Q/ LM3431AQ Features ■ LM3431Q/LM3431AQ are Automotive Grade products that are AEC-Q100 grade 1 qualified (-40° ...
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Connection Diagram Ordering Information Order Number Operating Temp Range LM3431MHX -40°C to 125°C LM3431MH -40°C to 125°C LM3431AMHX -40°C to 125°C LM3431AMH -40°C to 125°C LM3431QMHX -40°C to 125°C LM3431QMH -40°C to 125°C LM3431AQMHX -40°C to 125°C LM3431AQMH -40°C to ...
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Pin Descriptions Pin # Pin Name 1 VIN Power supply input. 2 PGND Power ground pin. Connect to ground. 3 VCC Internal reference voltage output. Bypass to PGND with a minimum 4.7 µF capacitor Boost controller gate drive ...
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... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Voltages from the indicated pins to SGND: VIN EN DIM MODE/F REFIN THM DLY SNSx NDRVx CFB SC AFB Electrical Characteristics apply over the junction temperature (TJ) range of -40°C to +125°C. Unless otherwise stated, V limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm 25° ...
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Symbol Parameter bw SNSx amp bandwidth V LEDOFF voltage LEDOFF V DIM threshold DIM hysteresis T Minimum internal DIM pulse width DIM (Note 8) DIM DIM to NDRV delay time DLY_R DIM DIM to NDRV delay time DLY_F TH MODE/F ...
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Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device is intended to be functional. For guaranteed specifications and test conditions, see the Electrical Characteristics. ...
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Typical Performance Characteristics 12V 25° vs. Temperature REF SNS Temperature (LM3431 or LM3431A) OS IQ_SB vs Temperature Unless otherwise specified the following conditions apply Voltage vs. Temperature FB 30041104 ...
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Normalized Switching Frequency vs. Temperature (700 kHz) Line Transient Response LED Ripple Current www.national.com Efficiency vs. Input Voltage LED Current = 140 LED Vf = 25V 30041110 Dimming Transient Response 30041112 30041114 8 30041111 30041113 NDRV Waveforms ...
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Block Diagram 9 30041116 www.national.com ...
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www.national.com 10 ...
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Operation Description The LM3431 combines a boost controller and 3 constant cur- rent regulator controllers in one device. To simplify the de- scription, these two blocks will be described separately as Boost Controller and LED Current Regulator. All descriptions and ...
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SS/SH voltage below its maximum. The AFB pin voltage at the end of softstart is 1.85V typically, which determines the ratio of the feedback resistors according to the following equa- tion: The AFB resistors also set the output over-voltage (OVP) ...
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Where I is the sum of all LED string currents at 100% dim- OUT ming. I will be highest at the minimum input voltage. L(AVE) Then determine the minimum L based on Δi ing equation: A good starting point is ...
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It may also be necessary to add additional V capacitance for low V operation. IN DIODE SELECTION The average current through D1 is the average load current (total LED current), and the peak current through the diode is the ...
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INPUT CAPACITOR SELECTION Because the inductor is at the input of a boost converter, the input current waveform is continuous and triangular. The in- ductor ensures that the input capacitor sees relatively low ripple currents. The rms current in the ...
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Once the control-to-output response has been determined, the compensation components are selected. A series combi- nation of Rc and Cc is recommended for the compensation network, shown as R9 and C4 in the typical application circuit. The series combination of ...
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NDRV The NDRV pins drive the base of the external NPN or N- channel MOSFET current regulators. Each pin is capable of driving base current typically. Therefore, NPN devices with sufficient gain must be selected. ...
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To ensure good linearity, select NPN regulators with short and similar rise and fall times. SETTING FF To minimize voltage transients during LED dimming, the out- put voltage is regulated via the AFB pin during LED off times. However, ...
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DLY pin remains high. In this condition, the DLY pin will charge to a maximum of 3.6V (typical). In case of a Type 2 fault, when the DLY voltage reaches 2.8V (typical), the LM3431 will shut down ...
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DLY to charge. Shorted LED If an LED fails short circuit, the SC voltage will increase. When SC reaches 3.1V, the same Type 1 fault as an open LED ...
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During startup (and re-start), the THM monitor is active. Therefore, the thermistor temperature must be below the restart threshold for the LM3431 to startup. TSD If the LM3431 ...
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The current sensing circuitry in current mode controllers can be easily affected by switching noise. Although the LM3431 imposes 170ns of blanking time at the beginning of every cy- cle to ignore this noise, some may remain after the blanking ...
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Physical Dimensions inches (millimeters) unless otherwise noted eTSSOP-28 Package 28 Lead Exposed Pad TSOP Package NS Package Number MXA28A 23 www.national.com ...
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