RT8280 RICHTEK [Richtek Technology Corporation], RT8280 Datasheet
RT8280
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RT8280 Summary of contents
Page 1
... Step-Down Converter General Description The RT8280 is a high voltage buck converter that can support an input voltage range from 4.5V to 24V with output current up to 3A. Current mode operation provides fast transient response and eases loop stabilization. The chip provides protection functions such as cycle-by- cycle current limiting and thermal shutdown protection. In shutdown mode, the regulator only draws 25μ ...
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... SW 4, GND 9 (Exposed Pad COMP © Copyright 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com BOOT VIN C IN 10µF RT8280 (Exposed Pad) GND 6 COMP R2 (kΩ) R (kΩ ...
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... Shutdown 3V Comparator © Copyright 2012 Richtek Technology Corporation. All rights reserved. DS8280-02 March 2012 Oscillator CC Foldback Control 0. Comparator + 0. COMP RT Current Sense Slope Comp Amplifier + - Current Comparator 0. registered trademark of Richtek Technology Corporation. RT8280 V A BOOT SW GND www.richtek.com 3 ...
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... RT8280 Absolute Maximum Ratings V ---------------------------------------------------------------------------------------------------------------- IN SW --------------------------------------------------------------------------------------------------------------- −0. BOOT ----------------------------------------------------------------------------------------------------------- (SW − 0.3V) to (SW + 6V) All Other Pins ------------------------------------------------------------------------------------------------- −0. Power Dissipation 25° SOP-8 (Exposed Pad) -------------------------------------------------------------------------------------- 1.333W Package Thermal Resistance (Note 2) SOP-8 (Exposed Pad) , θ -------------------------------------------------------------------------------- 75°C/W JA SOP-8 (Exposed Pad) , θ ------------------------------------------------------------------------------- 15°C/W JC Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------ 260°C Junction Temperature ---------------------------------------------------------------------------------------- 150° ...
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... Note 4. The device is not guaranteed to function outside its operating conditions. © Copyright 2012 Richtek Technology Corporation. All rights reserved. DS8280-02 March 2012 Symbol Test Conditions 2V SHDN registered trademark of Richtek Technology Corporation. RT8280 Min Typ Max Unit 1 0.4 μ 0 μ ° ...
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... RT8280 Typical Operating Characteristics Efficiency vs. Output Current 100 12V 0.0 0.5 1.0 Output Current (A) Output Voltage vs. Output Current 5.30 5.25 5.20 5.15 5.10 5.05 5.00 4.95 4.90 4.85 4.80 4.75 4.70 0.0 0.5 1.0 Output Current (A) Reference Voltage vs. Temperature 0.810 0.805 0.800 0.795 0.790 0.785 0.780 -50 - Temperature (°C) © Copyright 2012 Richtek Technology Corporation. All rights reserved. ...
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... V SW (5V/Div (2A/Div OUT Time (200ns/Div) Load Transient Response V OUT I OUT V = 12V (1A/Div 1.5A to 3A, f OUT Time (100μs/Div registered trademark of Richtek Technology Corporation. RT8280 = 3.3V 2.2MHz 100 125 = 12V 3.3V OUT = 3A 2.2MHz SW = 3.3V OUT = 2.2MHz SW www.richtek.com 7 ...
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... RT8280 Power On from (2V/Div) V OUT (1V/Div (2V/Div) l OUT Time (400μs/Div) Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com (2V/Div) V OUT (1V/Div 12V 3.3V IN OUT (2V/Div 2.2MHz registered trademark of Richtek Technology Corporation. ...
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... Vout curve. Except the minimum on-time constraint, the limit of maximum duty also needs to be considered. In ideal case, the duty cycle of the RT8280 can be calculated by below equation, But in practical case it will be higher than the calculation result since all the components in a converter circuit are not ideal ...
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... RT happens in high frequency operation and with slow rising input voltage. It can easily be solved by adding a voltage divider on the EN pin. The RT8280 will be enabled when the input voltage rises close to the nominal input voltage. Inductor Selection The inductor value and operating frequency determine the ripple current according to a specific input and output voltage. The ripple current Δ ...
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... OUT ⎡ ⎤ 1 ≤ Δ ESR OUT L ⎢ ⎥ ⎣ 8fC ⎦ OUT increases with input voltage. Multiple best, this ringing can couple to the output IN large enough to damage the registered trademark of Richtek Technology Corporation. RT8280 www.richtek.com 11 ...
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... OUT or ringing to indicate any stability problem. Compensation Parameters The switching frequency of the RT8280 can be programmed from free running frequency to 3MHz. Table 1 only lists the recommended compensation parameters for 2.2MHz switching frequency. Optimized compensation parameters for other switching frequency can also be determined through below procedures ...
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... J (MAX) (a) Copper Area = (2.3 x 2.3) mm (b) Copper Area = 10mm (c) Copper Area = 30mm 2 (d) Copper Area = 50mm 2 (e) Copper Area = 70mm 2 Figure 7. Themal Resistance vs. Copper Area Layout Design is a registered trademark of Richtek Technology Corporation. RT8280 , θ = 75°C θ = 64°C θ = 54°C θ ...
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... Ambient Temperature (°C) Figure 8. Derating Curves for RT8280 Package capacitors. Keep the loop area small. Place the feedback components near the RT8280. Connect all analog grounds to a common node and then connect the common node to ground behind the output capacitors. ...
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... Richtek Technology Corporation. All rights reserved. DS8280-02 March 2012 Table 4. Suggested Capacitors for C Part No. GRM31CR61E106K C3225X5R1E106K TMK316BJ106ML GRM31CR60J476M C3225X5R0J476M GRM32ER71C226M C3225X5R1C226M and C IN OUT Capacitance (μ registered trademark of Richtek Technology Corporation. RT8280 Case Size 1206 1206 1206 1206 1210 1210 1210 www.richtek.com 15 ...
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... RT8280 Outline Dimension EXPOSED THERMAL PAD (Bottom of Package) Symbol Option 1 Option 2 Richtek Technology Corporation 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete ...