s-8425 Seiko Instruments Inc., s-8425 Datasheet
s-8425
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s-8425 Summary of contents
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... Digital cameras • Memory cards • SRAM backup equipment The S-8425 Series is a CMOS IC designed for use in the switching circuits of primary and backup power supplies on a single chip. It consists of three voltage regulators, two voltage detectors, a power supply switch and its controller, as well as other functions ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series Product Name Structure 1. Product Name S-8425 Product Name List Item Package Product name S-8425AAAFT-TB-G 8-Pin TSSOP S-8425AAAPA-TF-G 8-Pin SON(B) Caution Set the CS voltage so that the switch voltage (V detection voltage (−V Remark The selection range is as follows. ...
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... Rev.2.3 _00 Block Diagram VIN detector CS Voltage CS detector BATTERY BACKUP SWITCHING IC VOUT REG2 V SW1 V SW2 detector Switch controller VSS Figure 1 Block Diagram Seiko Instruments Inc. S-8425 Series M1 RESET Voltage detector Delay circuit REG1 REG3 VBAT RESET VRO VCH 3 ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series Pin Configurations 8-Pin TSSOP Top View 1 8 VSS VBAT 8-Pin SON(B) Top View 1 VSS 2 VCH VBAT Figure 2 Pin Configurations *1. Mount capacitors between VSS (GND) and the VIN, VBAT, VOUT, VRO, and VCH pins (see the Standard Circuit section) ...
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... T stg 114.3 mm × 76.2 mm × t1.6 mm (2) When not mounted on board 400 8-Pin SON(B) 300 200 100 0 150 100 Figure 3 Power Dissipation of Package Seiko Instruments Inc. BATTERY BACKUP SWITCHING IC S-8425 Series Ratings −0 + −0 + −0 +0 − ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series Electrical Characteristics S-8425AAAFT, S-8425AAAPA Parameter Output voltage 1 Dropout voltage 1 Load stability 1 Input stability Output voltage temperature coefficient 1 l Output voltage Dropout voltage 2 g Load stability 2 e Input stability Output voltage temperature coefficient 2 ...
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... Oscilloscope OUT ↓ measure I and measure I Oscilloscope Figure 4 Test Circuits Seiko Instruments Inc. BATTERY BACKUP SWITCHING IC S-8425 Series 100 kΩ 100 kΩ VBAT VOUT VIN RESET VSS VOUT VIN VBAT V BAT VSS VIN VBAT ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series Timing Chart V ( (V) RO (V) OUT V (V) BAT V ( (V) RESET t DELAY Remark CS and are pulled RESET 8 t DELAY . The Y-axis is an arbitrary scale. OUT Figure 5 Timing Chart Seiko Instruments Inc. Rev.2.3 _00 ...
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... The functions and operations of the above-listed elements are described below. 1. Voltage Regulators The S-8425 Series features on-chip voltage regulators with a small dropout voltage. The voltage of the VRO, VOUT, and VCH pins (the output pins of the voltage regulator) can separately be selected for the output voltage in 0 ...
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... RESET pin: “Low” for a lower voltage than the detection level and “High” for a higher voltage than the release level. RESET outputs the normal logic if the V OUT pin voltage is 1 more. The S-8425 Series incorporates a RESET release delay circuit. [RESET release delay time (t The interval from when the VOUT pin voltage exceeds the RESET release voltage value ( + V output of the RESET pin is actually inverted is called the RESET release delay time ...
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... CS release voltage IN reaches more than the CS release voltage ( + V IN According to Power Supply Voltage V Voltage Regulator 2 Switch Transistor OFF Seiko Instruments Inc. BATTERY BACKUP SWITCHING IC S-8425 Series ). DET1 voltage due to an undershoot. SW2 ) sequence: a special BAT rises and becomes IN ). DET1 IN ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series 3.4 Switch Transistor M1 Voltage regulator 2 is also used to switch from the VIN pin to the VOUT pin. Therefore, no reverse current flows from the VOUT pin to the VIN pin when voltage regulator 2 is OFF. The output voltage of voltage regulator 2 can be selected from between 2.3 V and 5 0.1 V steps. The on-resistance of switch transistor Ω ...
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... BATTERY BACKUP SWITCHING IC Fast amplifier Overshoot P.G. Undershoot Figure 11 Test Circuit VRO pin C RO Input voltage (5 V/div) Output voltage (0.5 V/div) Figure 13 Ringing Waveform of Power Seiko Instruments Inc. S-8425 Series S-8425 VIN Oscillo- VOUT Series scope C VSS OUT μ mA ° ...
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... OUT 10V 6V t (100 μ s/div μ 10V 6V t (100 μ s/div) Seiko Instruments Inc. Rev.2.3 VIN VOUT S-8425 Series R VSS C OUT Figure 16 Test Circuit = 50 mA ° C OUT = 30 mA ° _00 Oscillo- scope L ...
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... Rev.2.3 _00 VCH pin Input voltage 10V (4 V/div) 6V Output voltage (50 mV/div) Figure 19 Ringing Waveform of Power Supply Variation (VCH Pin) BATTERY BACKUP SWITCHING μ mA ° 10V 6V t (100 μ s/div) Seiko Instruments Inc. S-8425 Series 15 ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series Reference data: Dependency of output current (I input variation width (ΔV For reference, the following pages describe the results of measuring the ringing amounts at the VOUT and VRO pins using the output current (I OUT as parameters. 1.1 I Dependency OUT (1) VOUT pin = 22 μ ...
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... and ° 0.50 0.40 0.30 0.20 0.10 0. (μF) CH (2) VRO pin = 30 mA 0.50 0.40 0.30 0.20 0.10 0. Seiko Instruments Inc. BATTERY BACKUP SWITCHING IC S-8425 Series = 6 V and ° μ Overshoot Undershoot 50 17 ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series 1.3 ΔV Dependency IN Δ V shows the difference between the low voltage fixed and the high voltage. IN For example, Δ means the difference between 6 V and (1) VOUT pin = 50 mA μ ° OUT OUT 0 ...
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... Ta (°C) (3) VCH pin 0. and 0. μ 0.20 0.15 0.10 0.05 0.00 − ° C) (2) VRO pin 50 100 50 100 Seiko Instruments Inc. BATTERY BACKUP SWITCHING IC S-8425 Series 0.30 0.25 0.20 0.15 0. and 0. μ 0.00 − (°C) Overshoot Undershoot 100 19 ...
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... Figure 22 Ringing Waveform due to Load Variation (VOUT Pin between 10 μ A and 10 mA) while the input voltage CH The latter half of this section describes ringing waveform and parameter VIN S-8425 Series Undershoot V Seiko Instruments Inc. VOUT C OUT VSS Figure 21 Test Circuit = 6 ...
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... Figure 24 Ringing Waveform due to Load Variation (VCH Pin) BATTERY BACKUP SWITCHING μ 6 μ A Seiko Instruments Inc. S-8425 Series = 22 μ ° (50 μ s/div μ ° (50 μ s/div) 21 ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series Reference data: Dependency of input voltage (V output variation width (ΔI 2.1 V Dependency IN (1) VOUT pin = 22 μ and 10 μ ° OUT OUT 0.12 0.10 0.08 0.06 0.04 0.02 0. (V) IN (3) VCH pin = 10 μ and 10 μ ° C ...
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... and 10 μ ° 0.60 0.50 0.40 0.30 0.20 0.10 0. μ BATTERY BACKUP SWITCHING IC (2) VRO pin = 6 0.30 0.25 0.20 0.15 0.10 0.05 0. Seiko Instruments Inc. S-8425 Series = 30 mA and 10 μ ° μ Overshoot Undershoot 23 ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series 2.3 ΔI Dependency OUT Δ I and Δ I show the fluctuation between the low current stabilized at 10 μ A and the high current. OUT RO For example, Δ means a fluctuation between 10 μ A and 10 mA. OUT (1) VOUT pin = 22 μ ° C ...
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... and 10 μ 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 − ° C) BATTERY BACKUP SWITCHING IC (2) VRO pin = 22 μ 6 OUT IN 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.00 50 100 = 10 μ 100 Seiko Instruments Inc. S-8425 Series = 30 mA and 10 μ μ − 100 Ta ( ° C) Overshoot Undershoot 25 ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series Standard Circuit Caution • Be sure to add a 10 μF or more capacitor to the VOUT, VRO, and VCH pins. • The above connections and values will not guarantee correct operation. Before setting these values, perform sufficient evaluation on the application to be actually used ...
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... RO OUT μ F VCH VOUT VIN VRO S-8425 100 k Ω 100 k Ω Series VBAT CS RESET VSS Figure 26 Application Circuit Seiko Instruments Inc. S-8425 Series V , and V RO OUT , to 10 μ more OUT μ F VCC + Microcontroller 10 μ F INT RESET ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series Characteristics 1. Voltage Regulator Unit 1.1 Input Voltage (V ) vs. Output Voltage ( ° mA, 30 mA, 50 mA 2.8 2.4 2.0 2.0 3.0 V ( − 40 ° mA, 30 mA, 50 mA 3.2 RO 2.8 2.4 2.0 2.0 3.0 V (V) IN 1.2 Input Voltage ( ...
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... Ta = − 40 ° mA, 30 mA 3.5 CH 3.1 2.7 2.3 3.0 2.0 4.0 5.0 V (V) IN BATTERY BACKUP SWITCHING IC ) Characteristics (REG3) (V OUT ( ° mA, 30 mA 3.1 2 2.3 6.0 7.0 2 6.0 7.0 Seiko Instruments Inc. S-8425 Series = 3 3.0 4.0 5.0 6.0 V (V) IN 7.0 29 ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series 1.4 Output Current (I ) vs. Dropout Voltage Characteristics drop1 1 ° ° C 0.8 − 40 ° C 0.6 0.4 0.2 0.0 0 0.02 ( 1.6 Output Current (I ) vs. Dropout Voltage Characteristics drop3 2 ° C 1.6 25 ° C − 40 ° C 1.2 0.8 0.4 0.0 0 0.02 I (A) CH 1.7 Output Current (I ) vs. Output Voltage ...
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... Input Stability ( Δ 100 60 80 100 Seiko Instruments Inc. BATTERY BACKUP SWITCHING IC S-8425 Series ) Temperature OUT Characteristics OUT Based on V voltage when Ta is 25°C OUT −40 − (°C) ) Temperature ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series 1.16 Load Stability ( Δ Temperature RO1 Characteristics − 40 − ° C) 1.18 Load Stability ( Δ Temperature CH1 Characteristics − 40 − ° 1.17 Load Stability ( Δ 100 100 Seiko Instruments Inc. ...
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... 100 = 2.4 V) DET2 (2) Output current (I ) temperature ) voltage 100 (4) RESET release delay time = 0 100 Seiko Instruments Inc. BATTERY BACKUP SWITCHING IC S-8425 Series ) characteristics SINK 25 ° 0.0 1.0 2.0 3 characteristics SINK ° ...
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... BATTERY BACKUP SWITCHING IC S-8425 Series 3. Switch Unit 3.1 Switch Voltage (V ) Temperature SW1 Characteristics 20 10 voltage when ° C Based on V SW1 0 − 10 − 20 − 40 − ° C) 3.3 Input Voltage (V ) vs. V BAT Resistance (R ) Characteristics OUT BAT 3 ...
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... BAT − 20 − ° 4.2 V SS1 ( 100 Seiko Instruments Inc. BATTERY BACKUP SWITCHING IC S-8425 Series vs. V Current Consumption (I BAT BAT2 Characteristics 2 ° ° C − 40 ° C 1.5 1.0 0.5 0.0 2.0 2.4 2.8 3.2 V (V) BAT BAT2 2.0 = open 3.0 V 1.5 V ...
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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 ...