lm26484sqx National Semiconductor Corporation, lm26484sqx Datasheet
lm26484sqx
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lm26484sqx Summary of contents
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... MHz PWM switching frequency ■ ±1% feedback voltage accuracy ■ Automatic soft start ■ Current overload protection ■ PWM/PFM efficiency modes available © 2008 National Semiconductor Corporation LINEAR REGULATOR (LDO) CONTROLLER ■ 3.0V–5.5V Input range ■ Externally adjustable V ■ ±1.5% feedback voltage accuracy ■ ...
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Application Circuit www.national.com FIGURE 1. Application Circuit 2 30066101 ...
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... UZXYTT format: ‘U’ – wafer fab code; ‘Z’ – assembly code; ’XY’ 2 digit date code; ‘TT” – die run code. See http://www.national.com/quality/marking_conventions.html for more information on marking information. Ordering Information Part Number Package Marking LM26484SQE 26484SQ LM26484SQ 26484SQ LM26484SQX 26484SQ 24-Lead LLP Package (top view) Ordering Buck1 Buck2 Spec NOPB PWM ...
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Pin Descriptions Pins Name 1 VIN1 2 ENSW1 3 FB1 4 AVIN 5 FB2 6 ENSW2 7 VIN2 8 VIN2 9 SW2 10 SW2 11 PGND_SW2 12 PGND_SW2 13 ENLDO 14 LDOGATE 15 LDOFB 16 AGND 17 GND 18 nPOR ...
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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. VIN1, VIN2, AVDD, AVIN nPOR, ENSW1, FB1, ENSW2, FB2, ENLDO, LDO_FB GND to GND SLUG Junction Temperature (T ) ...
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Buck Converters SW1, SW2 Unless otherwise noted, AVDD=AVIN=VIN1=VIN2 = 3.3V, C Buck2 is configured to 1.0V. Typical values and limits appearing in normal type apply for T type apply over the entire junction temperature range for operation, −40°C to +125°C. ...
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Typical Performance Characteristics — LDO Load Transient V — 1.0V, I OUT Typical Performance Characteristics — Buck Startup of Buck1 1.8V; I OUT Startup of Buck2 1.0V; I OUT T = 200 mA-1A Load Transient V ...
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Line Transient 250 mA; V OUT Buck1 Load Transient 1.8V 250 mA - 1.5A OUT OUT Buck2 Load Transient 1.0V 250 mA - 1.5A OUT OUT ...
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Efficiency of Buck1 1.8V, at Room Temp OUT Efficiency of Buck1 3.5V at Room Temp OUT Flexible Power Sequencing of Multiple Power Supplies The two bucks and the LDO in the LM26484 can be individ- ually ...
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LDO Functional Description The LDO is a linear regulator which targets analog loads characterized by low noise requirements. The LDO is enabled through the ENLDO pin. The output voltage is determined by the configuration of the external feedback resistors, as ...
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Buck Regulator Functional Description The LM26484 incorporates two high efficiency synchronous switching buck regulators which are 180° out of phase, SW1 and SW2 that deliver voltages from a single DC input voltage. Using a voltage mode architecture with synchronous rectifi- ...
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SOFT START The soft-start feature allows the power converter to gradually reach the initial steady state operating point, thus reducing start-up stresses and surges. The two LM26484 buck con- verters have a soft-start circuit that limits in-rush current dur- ing ...
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Component Selection SW1, SW2 OPERATION TABLE 2. Buck1/2 Configuration and Component Selection Guide Target Ideal Resistor Values V (V) R1/3 (KΩ) R2/4 (KΩ) OUT 0.8 120 200 0.9 160 200 1 200 200 1.1 240 200 1.2 280 200 1.3 ...
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FIGURE 4. Typical Variation in Capacitance vs. DC Bias As shown in , increasing the DC Bias condition can result in a capacitance value that falls below the minimum value given in the recommended capacitor specifications table. Note that the ...
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I : Inductor saturation current at operating tempera- SAT ture I : Peak inductor current during worst case conditions LPEAK Inductor Value Unit L1 and L2 0.5 µH SUGGESTED INDUCTORS AND THEIR SUPPLIERS Model Vendor Dimensions (mm) LPS4414–501ML Coilcraft ...
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A simplified “worst case” assumption is that all of the PFET current is supplied by the input capacitor. This will result in conservative estimates of input ripple voltage and capacitor RMS current. Input ripple voltage is estimated as follows: Model ...
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Physical Dimensions inches (millimeters) unless otherwise noted 0.8 mm 24-Pin LLP Package Order Number LM26484SQA NS Package SQA24B 17 www.national.com ...
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