s-8551 Seiko Instruments Inc., s-8551 Datasheet
s-8551
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s-8551 Summary of contents
Page 1
... The built-in synchronous rectification circuit makes achieving high efficiency easier compared with conventional step-down switching regulators. A ceramic capacitor can be used as an output capacitor. supported by adopting a small SOT-23-5 package. The S-8550 and S-8551 Series are offered according to different pin configuration. 1.2 MHz 2.0 to 5.5 V Arbitrarily settable by external output voltage setting resistor 600 mA 0.6 V ± ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series Block Diagram *1. Parasitic diode 2 Current limit circuit Error amplifier − + PWM control + circuit − Reference PWM comparator voltage Triangular wave generation circuit ON/OFF UVLO circuit circuit ON/OFF Figure 1 Seiko Instruments Inc ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS Rev.2.1 _01 Product Name Structure Product name S-855 x A *1. Refer to the taping specifications at the end of this book. *2. Refer to Table 1 and Table 2 of “ M5T1 G Package name (abbreviation) and packing specification M5T1 : SOT-23-5 Oscillation frequency ...
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... ON/OFF “H” : Power on (normal operation) “L” : Power off (standby Output voltage feedback pin 5 CONT External inductor connection pin Table 2 S-8551 Series (Pin Configuration 2) Pin No. Symbol Shutdown pin 1 ON/OFF “H” : Power on (normal operation) “L” : Power off (standby) 2 ...
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... The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. 2. Since this IC has a built-in power MOS FET, make sure that dissipation of the power MOS FET does not exceed the allowable power dissipation of the package. (Refer to Figure 3.) Generally, dissipation of a switching regulator can be calculated by the following equation. Dissipation = (100 (%) − ...
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... TDK Corporation IN 10 µF C TDK Corporation OUT R 36 kΩ Rohm Co., Ltd. FB1 R 18 kΩ Rohm Co., Ltd. FB2 68 pF Murata Manufacturing Co., Ltd. FB Seiko Instruments Inc. = 1.8 V (the conditions in Table 5 25°C) OUT Min. Typ. Max. Unit 2.0 5.5 1.1 4.0 0.588 0.6 0.612 ±100 ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS Rev.2.1 _01 Test Circuits VIN CONT FB C S-855xA IN ON/OFF VSS Figure 4 VIN CONT C S-855xA IN FB ON/OFF VSS Figure 5 Seiko Instruments Inc. S-8550/8551 Series ↓ OUT C C OUT FB R FB1 I OUT ↓ ...
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... The soft-start circuit built in the S-8550/8551 Series controls the rush current and the overshoot of the output voltage when powering on, the ON/OFF pin is switched from the “L” level to the “H” level, or the UVLO operation is released. A reference voltage adjustment method is adopted as the soft-start method. ...
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... A slight overshoot is generated in the output voltage when the current limit is released. The current limit detection value is fixed (typ.) in the IC. If the time taken for the current limit to be detected is shorter than the time required for the current limit circuit in the IC to detect, the current value that is actually limited increases ...
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... A step-down switching regulator starts current supply by the input voltage (V turned on and holds energy in the inductor at the same time. When the Pch power MOS FET is turned off, the current held in the inductor is released. The released current flows in the smoothing circuit, with the energy loss ...
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... OUT made 0 mA and no backflow current flows. When an input capacitor (C current to flow in the power supply. Be sure to connect an input capacitor to reduce backflow current to the power supply (see Figure 10). The above presents the conditions required to prevent backflow current from flowing, which is only a guideline. ...
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... L is decreased further, the current drive capability of the external transistor is insufficient and I If the L value is increased, the loss due to I maximum at a certain L value. Further increasing L decreases the efficiency due to the increased loss of the DC resistance of the inductor. The recommended L value for the S-8550/8551 Series is 3.3 µH. ...
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... However, since the gain becomes higher in the range of high frequency, the total phase of feedback loop delays 180° or more by setting the zero point frequency in the significantly lower range result, the gain cannot lower in the frequency range thus the operation might be unstable. Determine the proper value after the sufficient evaluation under the actual condition ...
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... Although the IC contains a static electricity protection circuit, static electricity or voltage that exceeds the limit of the protection circuit should not be applied. • The power dissipation of the IC greatly varies depending on the size and material of the board to be connected. Perform sufficient evaluation using an actual application before designing. • ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS Rev.2.1 _01 Characteristics (Typical Data) 1. Example of Major Power Supply Dependence Characteristics (Ta = 25° Current consumption 1 (I 500 400 300 200 100 0 2.0 2.5 3.0 3 Oscillation frequency (f osc 1.38 1.34 1.30 1.26 1.22 1.18 1.14 1.10 1.06 1.02 2.0 2.5 3.0 3 Power MOS FET on-resistance (R ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series voltage (V ) vs. Input voltage (V FB 612 608 604 600 596 592 588 2.0 2.5 3.0 3.5 2. Example of Major Temperature Characteristics (Ta = −40 to 85° Current consumption 1 (I 500 V IN 400 300 200 100 0 −40 − Oscillation frequency (f 1.32 1.28 1 ...
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... Ta [° UVLO detection voltage (V 1.80 1.75 1.70 1.65 1.60 1.55 1.50 1.45 1.40 −40 − [°C] 3. Examples of Transient Response Characteristics (Unless otherwise specified, the used parts are ones shown Powering 1 OUT ( OUT OUT 0 − −0.2 0 0.2 0.4 0.6 0.8 t [ms] 3 ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series 3. 3 Power supply fluctuations (V = 2.6 V → 3.6 V → 2 mA, V OUT 2.2 2.0 V OUT 1.8 1.6 1.4 −0.1 0 0.1 0.2 0.3 t [ms Load fluctuations (V OUT ( 0.1 mA → 100 mA → 0.1 mA OUT I OUT 1.90 1.85 V OUT 1.80 1.75 1.70 −0.1 0 0.1 0.2 0.3 t [ms 1 25° ...
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... Input capacitor C3216X7R1E475K Output capacitor C3216X7R1C106K Caution The values of the external parts are based on the materials provided by each manufacturer. However, consider the characteristics of the original materials when using the above products. 2. Output current (I ) vs. Efficiency (η) Characteristics and Output current (I OUT 2 ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series = 3 kΩ OUT FB1 Output current (I (1) OUT 100 3 5 OUT = 4 kΩ OUT FB1 Output current (I ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS Rev.2.1 _01 = 1 kΩ OUT FB1 ( 3 OUT = 3 kΩ OUT FB1 ( 3 OUT = 4 kΩ ...
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... Product name vs. Product code (a) S-8550 Series Product Name S-8550AA-M5T1G 22 Product code (Refer to Product name vs. Product code.) (1) to (3) : (4) : Lot number (b) S-8551 Series Product Code (1) (2) ( S-8551AA-M5T1G Seiko Instruments Inc. Product Code Product Name (1) (2) R Rev.2.1 ...
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... Use of the information described herein for other purposes and/or reproduction or copying without the express permission of Seiko Instruments Inc. is strictly prohibited. The products described herein cannot be used as part of any device or equipment affecting the human body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus installed in airplanes and other vehicles, without prior written permission of Seiko Instruments Inc ...