S-8821 Seiko Instruments, S-8821 Datasheet
S-8821
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S-8821 Summary of contents
Page 1
... Power supply for white LED display backlights Packages Package Name SOT-23-6W The S-8821 series is a CMOS step-up charge pump DC-DC converter with a voltage regulation function. The S-8821 series consists of an oscillation circuit, a controller, a reference voltage circuit, an error amplifier circuit, and an output switching transistor, and can regulate the output voltage by PFM control ...
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... VOLTAGE REGULATION STEP-UP CHARGE PUMP DC-DC CONVERTER S-8821 Series Block Diagram VIN =4.7 μ =0.10 μ PUMP C− 2 SW1 SW2 PFM control Switch oscillator control circuit (1.0 MHz) SW3 Soft start circuit SW4 ON/OFF Figure 1 Seiko Instruments Inc. VOUT circuit ...
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... Product Name Structure • The output voltage and packages for the S-8821 Series can be selected at the user’s request. Refer to the “Product name” for the meanings of the characters in the product name and “Product name list” for the full product names. ...
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... VOLTAGE REGULATION STEP-UP CHARGE PUMP DC-DC CONVERTER S-8821 Series Pin Configurations SOT-23-6W Top view Figure 2 4 Table 2 Pin No. Symbol 1 VIN Voltage input pin Charge-pump pump capacitor connection pin 2 C+ (positive pin) Charge-pump pump capacitor connection pin 3 C− ...
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... T stg 114.3 mm × 76.2 mm × t1.6 mm (2) When not mounted on board 400 350 300 250 200 150 100 50 0 100 150 0 Figure 3 Power Dissipation of Package Seiko Instruments Inc. S-8821 Series (Ta=25°C unless otherwise specified) Units +7.5 V GND +7 V GND +5.5 V GND +7 V GND +0 ...
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... VOLTAGE REGULATION STEP-UP CHARGE PUMP DC-DC CONVERTER S-8821 Series Electrical Characteristics Items Symbols Operation input voltage Output voltage V OUT(E) *3 Output current I OUT ΔV Line regulation ΔV Load regulation *4 Ripple voltage V RIP Maximum oscillation f osc frequency η *5 Efficiency Operation consumption I SS1 ...
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... VOLTAGE REGULATION STEP-UP CHARGE PUMP DC-DC CONVERTER Rev.3.1 _00 Test Circuits 1. 4.7 μ 0.1 μF 4.7 μF A VIN VOUT C+ GND C− ON/OFF A A Figure 4 VIN VOUT C+ GND C− ON/OFF 10 μF A Figure 5 Seiko Instruments Inc. S-8821 Series A 7 Datasheet pdf - http://www.DataSheet4U.net/ ...
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... Basic operation Figure 6 shows the block diagram of the S-8821 Series. The S-8821 series controls the output voltage by using the pulse frequency modulation (PFM) method. The SW1 to SW4 switching transistors are switched ON/OFF with the clock generated by the internal oscillator circuit, and operates the step-up charge pump. ...
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... SW1 set the switches as to ON, SW2 to OFF, SW3 to ON, OUT OFF PUMP 0.10 μF Current flow OFF Figure OFF PUMP 0.10 μF Current flow SW 4: OFF Figure 8 Seiko Instruments Inc. S-8821 Series C OUT 10 μF C OUT 10 μF 9 Datasheet pdf - http://www.DataSheet4U.net/ ...
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... Figure 9 4. Soft Start Function The S-8821 Series features a built-in soft start circuit. Upon power application or when the is switched from "L" to "H", the output voltage gradually rises over the soft start time, and the output current is gradually output as a result. This soft start function reduces the input current rush. ...
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... IN ), select a ceramic capacitor with a small ESR for smoothing the ripple OUT ) PUMP ) is required for stepping up the voltage. Select a ceramic capacitor with a PUMP Seiko Instruments Inc. S-8821 Series 11 Datasheet pdf - http://www.DataSheet4U.net/ ...
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... VOLTAGE REGULATION STEP-UP CHARGE PUMP DC-DC CONVERTER S-8821 Series Precautions • Regarding the wiring to the VIN pin, VOUT pin, C+ pin, C− pin and GND pin, be careful to perform pattern wiring obtain low impedance. • Always connect a capacitor to the VOUT pin, C+ pin, and C− pin. ...
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... Operation consumption vs. Operation input voltage S-882133A 1.5 2.0 2.5 3.0 V S-882150A I =10 mA, Ta=25°C OUT 3.5 4.0 4.5 5.0 5.5 [V] IN S-882150A V =2.0 V, Ta=25° [mA] S-882150A Ta=25°C 3.5 4.0 4.5 5.0 5.5 [V] IN Seiko Instruments Inc. S-8821 Series I =10 mA, Ta=25°C OUT 5.30 5.20 5.10 5.00 4.90 4.80 4.70 1.5 2.0 2.5 3.0 3.5 4.0 4 =3.0 V, Ta=25°C IN 5.30 5.20 5.10 5.00 4.90 4.80 4. [mA] OUT Ta=25° ...
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... VOLTAGE REGULATION STEP-UP CHARGE PUMP DC-DC CONVERTER S-8821 Series (4) Ripple voltage vs. Operation input voltage S-882133A 100 1.5 2.0 2.5 3 (5) Efficiency vs. Operation input voltage S-882133A 100 1.5 2.0 2.5 3.0 V *1. The ideal efficiency is indicated by the following expression. Efficiency (η)=(V OUT (6) Maximum oscillation frequency vs. Operation input voltage ...
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... OUT CH2 mA/div.] OUT S-882150A I =10 mA OUT CH1 CH2 CH1: V [20 mV/div.] OUT CH2 V/div.] IN Seiko Instruments Inc. S-8821 Series V =3 ms/div.] CH1: V [20 mV/div.] OUT CH2 mA/div.] OUT I =10 mA OUT 5 ms/div.] CH1: V [20 mV/div ...
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... Datasheet pdf - http://www.DataSheet4U.net/ ...
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... Datasheet pdf - http://www.DataSheet4U.net/ ...
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... Datasheet pdf - http://www.DataSheet4U.net/ ...
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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 ...