S-8550 SII [Seiko Instruments Inc], S-8550 Datasheet
S-8550
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S-8550 Summary of contents
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... 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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... 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 A : 1.2 MHz Pin configuration setting 0 : Pin configuration Pin configuration 2 Pin Configurations”. Seiko Instruments Inc. S-8550/8551 Series , tape * ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series Pin Configurations SOT-23-5 Top view Figure 2 4 Table 1 S-8550 Series (Pin Configuration 1) Pin No. Symbol 1 VIN IC power supply pin 2 VSS GND pin Shutdown pin 3 ON/OFF “H” : Power on (normal operation) “ ...
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... T stg 700 600 500 400 300 200 100 Ambient temperature (Ta) [°C] Figure 3 Power Dissipation of Package (Mounted on Board) Seiko Instruments Inc. S-8550/8551 Series (Unless otherwise specified 25°C, V Absolute Maximum Rating − − − 0 0.3 ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series Electrical Characteristics (Unless otherwise specified: V Parameter Symbol Operating input voltage Output voltage range V OUT FB voltage V FB ∆V FB voltage temperature FB coefficient ∆Ta FB pin input current I FB Current consumption I SSS during shutdown ...
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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 ↓ FB2 V 7 ...
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... Soft-start function 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 ...
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... The S-8550/8551 Series operates up to the maximum duty cycle at 100%. Even when the input voltage is lowered up to the output voltage value set using the external output voltage setting resistor, the Pch power MOS FET is kept on and current can be supplied to the load ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series Operation Principle The S-8550/8551 Series is a step-down synchronous rectification switching regulator based on constant PWM control. Figure 7 shows the basic circuit diagram. 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 ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS Rev.2.1 _01 2. Backflow current The S-8550/8551 Series performs PWM synchronous rectification even if I current is generated in V Use the following equation to calculate the maximum backflow current value, which should be taken into consideration when designing. ...
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... 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. When selecting an inductor, note the allowable current of the inductor current exceeding this allowable current flows through the inductor, magnetic saturation occurs, substantially lowering the efficiency. ...
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... OUT A ceramic capacitor can be used for the input (C impedance and averages the input current to improve efficiency. Select C power supply to be used. The recommended capacitance is 4.7 µF for the S-8550/8551 Series when a general lithium ion rechargeable battery is used. Select capacitor with large capacitance and small ESR for smoothing the ripple voltage. ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series Standard Circuit Error amplifier FB Reference voltage 4.7 µF *1. Parasitic diode Caution The above connection diagram and constant will not guarantee successful operation. Perform thorough evaluation using an actual application to set the constants. ...
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... Soft-start time (t IN 4.0 4.5 5.0 5.5 [ vs. Input voltage ( Power MOS FET leakage current (I FET IN Pch Nch 4.0 4.5 5.0 5.5 [ vs. Input voltage ( ON/OFF pin input voltage“L” 4.0 4.5 5.0 5.5 [V] IN Seiko Instruments Inc. S-8550/8551 Series ) vs. Input voltage (V SSS 1.0 0.8 0.6 0.4 0.2 0 2.0 2.5 3.0 3.5 4 vs. Input voltage (V SS 1.3 1.2 1.1 1.0 0.9 0.8 0.7 2.0 2.5 3.0 3.5 4 ...
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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 − ...
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... External Parts When Measuring Electrical Characteristics .) = 0 V → 3 25°C) IN (2) I 0.6 0.4 0.2 0 −0.2 1.0 1.2 1.4 1 ON/OFF OUT IN (2) I 0.6 0.4 0.2 0 −0.2 1.0 1.2 1.4 1.6 Seiko Instruments Inc. S-8550/8551 Series ) vs. Temperature (Ta) SL 0.9 V 0.8 0.7 0.6 0.5 0.4 0.3 −40 − [°C] ) vs. Temperature (Ta) FB 612 V 608 604 600 596 592 588 −40 − ...
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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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... FB2 ) vs. Efficiency (η) (2) Output current (I 10 100 1000 [mA kΩ) FB2 ) vs. Efficiency (η) (2) Output current (I 10 100 1000 [mA] Seiko Instruments Inc. S-8550/8551 Series Characteristics 3.3 µH, DCR = 0.07 Ω, I MAX 4.7 µF 10 µF ) vs. Output voltage (V OUT OUT ) vs. Output voltage (V OUT ...
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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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... I OUT = 18 kΩ) FB2 ( 100 1000 [mA kΩ) FB2 ( 100 1000 [mA kΩ) FB2 10 100 1000 [mA] Seiko Instruments Inc. S-8550/8551 Series = 5 100 I [mA] OUT = 5 100 I [mA] ...
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... STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS S-8550/8551 Series Marking Specification (1) SOT-23-5 SOT-23-5 Top view 5 4 (1) (2) (3) ( 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) (3) ...
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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 ...