RT8271 RICHTEK [Richtek Technology Corporation], RT8271 Datasheet
RT8271
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RT8271 Summary of contents
Page 1
... Step-Down Converter General Description The RT8271 is a high voltage buck converter that can support the input voltage range from 4.75V to 24V and the output current can 2A. Current Mode operation provides fast transient response and eases loop stabilization. The RT8271 also provides adjustable soft- start flexible solution for customers ...
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... Function Block Diagram VIN V CC Internal Regulator 1µ 10k - Shutdown 3V Comparator V CC 10µA SS www.richtek.com 2 BOOT VIN C IN RT8271 10µF/25V 10nF COMP GND R (kΩ) C (nF 0.56 10 49.9 0. ...
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... If the EN pin is open, it will be pulled to high by internal circuit. Soft-Start Control Input. SS controls the soft start period. Connect a SS capacitor from SS to GND to set the soft-start period. A 10nF capacitor sets the soft-start period to 1ms. Pin Function supplies the power to the IC, as well as the RT8271 www.richtek.com 3 ...
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... RT8271 Absolute Maximum Ratings ----------------------------------------------------------------------------------------- −0.3V to 26V Supply Voltage Switching Voltage, SW ------------------------------------------------------------------------------------- −0. BOOT Voltage ------------------------------------------------------------------------------------------------ (V The Other Pins Voltage ------------------------------------------------------------------------------------- −0. Power Dissipation 25° SOP-8 ---------------------------------------------------------------------------------------------------------- 0.833W MSOP-10 (Exposed Pad) ---------------------------------------------------------------------------------- 1.163W Package Thermal Resistance (Note 2) SOP-8, θ ---------------------------------------------------------------------------------------------------- 120°C/W JA MSOP-10 (Exposed Pad), θ ...
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... Test Conditions SHDN 2V 10nF 25° high effective thermal conductivity four layers test board RT8271 Min Typ 1 0 150 is on the expose pad for MSOP-10 (Exposed Pad) www.richtek.com Max Unit 5.5 V 0.4 μ ...
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... RT8271 Typical Operating Characteristics Efficiency vs. Load Current 100 0.25 0.5 0.75 Load Current (A) Reference Voltage vs. Temperature 0.930 0.925 0.920 0.915 0.910 0.905 0.900 -50 - Temperature (°C) Quiescent Current vs. Temperature 0.80 0.75 0.70 0.65 0.60 0.55 0.50 -50 - Temperature (°C) www.richtek.com 3.3V OUT V = 2.5V OUT V = 12V ...
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... Switching Frequency vs. Temperature 1.30 1.25 1.20 1.15 1.10 1. 12V 1.00 -50 - Temperature (°C) Output Ripple OUT Time (1μs/Div) Load Transient Response V = 12V 2.5V IN OUT OUT OUT I OUT Time (100μs/Div) RT8271 = 2.5V 0.3A OUT OUT 75 100 125 V = 12V 2.5V OUT OUT www.richtek.com 7 ...
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... RT8271 Power On from EN Pin V EN (5V/Div) V OUT (1V/Div (500mA/Div) Time (250μs/Div) www.richtek.com (5V/Div) V OUT (1V/Div (500mA/Div 12V 2.5V OUT OUT Power Off from EN Pin V = 12V 2.5V OUT OUT Time (100μs/Div) DS8271-02 March 2011 ...
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... SW Figure 2. External Bootstrap Diode DS8271-02 March 2011 Soft-Start The RT8271 contains an external soft-start clamp that gradually raises the output voltage. The soft-start timming can be programed by the external capacitor between SS pin and GND. The chip provides a 10μA charge current for the external capacitor. If 10nF capacitor is used to set the soft-start and it’ ...
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... RT8271 Ferrite core material saturates “hard”, which means that inductance collapses abruptly when the peak design current is exceeded. The previous situation results in an abrupt increase in inductor ripple current and consequent output voltage ripple. Do not allow the core to saturate! Different core materials and shapes will change the size/ current and price/current relationship of an inductor ...
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... P D(MAX) SOP-8 The maximum power dissipation depends on operating ambient temperature for fixed T resistance θ . For RT8271 packages, the Figure derating curves allows the designer to see the effect of rising ambient temperature on the maximum power dissipation allowed. DS8271-02 March 2011 1.2 1 ...
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... RT8271 Input capacitor must be placed as close to the IC as possible. Figure 4. PCB Layout Guide for MSOP-10 (Exposed Pad) Input capacitor must be placed as close to the IC as possible. C OUT The output capacitor must be placed near the RT8271. www.richtek.com BOOT 10 BOOT ...
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... C IN OUT Part No. Capacitance (μF) GRM31CR61E106K C3225X5R1E106K TMK316BJ106ML GRM32ER61E226M GRM21BR60J226M C3225X5R0J226M EMK325BJ226MM V (V) I (A) Package RRM OUT DO-214AA 30 2 DO-214AA RT8271 Case Size 10 1206 10 1206 10 1206 22 1210 22 0805 22 1210 22 1210 SMA SMA www.richtek.com 13 ...
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... RT8271 Outline Dimension Symbol www.richtek.com Dimensions In Millimeters Min Max 4.801 5.004 3.810 3.988 1.346 1.753 0.330 0.508 1.194 1.346 0.170 0.254 0.050 0.254 5.791 6.200 0.400 1.270 8-Lead SOP Plastic Package H M Dimensions In Inches ...
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... No. 95, Minchiuan Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)86672399 Fax: (8862)86672377 Email: marketing@richtek.com Dimensions In Inches Min Max 0.032 0.043 0.000 0.004 0.030 0.037 0.007 0.011 0.114 0.122 0.020 0.189 0.197 0.114 0.122 0.016 0.031 0.051 0.067 0.059 0.075 RT8271 www.richtek.com 15 ...