bd9859efj ROHM Co. Ltd., bd9859efj Datasheet

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... Built-in Power MOSFET BD9859EFJ ●Summary Output 3.0A and below High Efficiency Rate Step-down Switching Regulator Power MOSFET Internal Type BD9859EFJ mainly used as secondary side Power supply, for example from fixed Power supply of 9V, 12V etc, Step-down Output of 1.2V/1.8V/3.3V/5V, etc, can be produced. This IC has external Coil/Capacitor down-sizing through 750kHz High Frequency operation, inside Nch-FET SW for 15V “ ...

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... BD9859EFJ ●Electrical Characteristics (Unless otherwise specified, Ta=25℃，VCC=12V, Vo=5V,EN=3V) Item 【Circuit Current】 Circuit Current during Standby Circuit Current during Operation 【Low Voltage Input Error Prevention Circuit】 Detect Threshold Voltage Hysteresis Width 【Oscillator】 Oscillation Frequency Max Duty Cycle 【Error Amp】 ...

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... BD9859EFJ ●Block Diagram ON/OFF EN TSD UVLO shutdown ERROR FB AMP - + 1.0V + Soft Start VC www.rohm.com ○ 2010 ROHM Co., Ltd. All rights reserved. c REG Reference VREF ICOMP Σ R　　Q S　　　 OSC 750kHz Fig.2 Block Diagram 3/15 Technical Note VCC BST 100mΩ Lx VOUT 5Ω ...

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... BD9859EFJ ●Block Description 1. Reference This Block generates Error Amp Standard Voltage. Standard Voltage is 1.0V. 2. REG This is a Gate Drive Voltage Generator and 5VLow Saturation regulator for internal Circuit Power supply. 3. OSC This is a precise wave Oscillation Circuit with Operation Frequency fixed to 750kHz fixed. ...

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... BD9859EFJ ●Reference Data (Unless otherwise specified, Ta=25℃，VCC=12V, Vo=5V,EN=3V) 0.6 0.5 0.4 0.3 0.2 VCC=14V VCC=12V 0.1 VCC=7V 0.0 -60 -40 - 100 Tem p (°C) Fig.3. Standby Current Temperature Characteristics 6.0 High Threshold 5.0 4.0 Low Threshold 3.0 2.0 1.0 0.0 -60 -40 - 100 Tem p (°C) Fig.6. UVLO Threshold Temperature Characteristics 1.2 1.0 VCC=14V 0.8 VCC=12V VCC=7V 0 ...

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... BD9859EFJ 6.0 5.0 4.0 3.0 VCC=14V VCC=12V 2.0 VCC=7V 1.0 0.0 -60 -40 - 100 Tem p (°C) Fig.12. Soft Start Time Temperature Characteristics 12.0 10.0 VCC=12V VCC=14V 8.0 6.0 VCC=8V 4.0 2.0 0.0 -60 -40 - 100 Tem p (°C) Fig.15 OCP Detect Current Temperature Characteristics www.rohm.com ○ 2010 ROHM Co., Ltd. All rights reserved. ...

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... BD9859EFJ ●Example of Reference Application Circuit (Input 12V, Output 5.0V/ 2.5A) VBAT CBAT 22 uF/ 16V GRM31CB31C226KE15 (murata) 4.7 uH (FDV0630 - 4R7M) 10 uF/ 6.3V GRM219B30J106KE18 (murata) VOUT COUT RFRA 0 Ω 120 kΩ RINV1 RINV2 30 kΩ ●Reference Application Data (Example of Reference Application Circuit) www.rohm.com ○ 2010 ROHM Co., Ltd. All rights reserved. ...

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... BD9859EFJ ●Reference Application Data (Example of Reference Application Circuit) Gain Phase [dB] [deg Phase Gain 0 0 -40 -90 100 10k 1M Frequency[kHz] Fig.20 Frequency Response Characteristics（Io=1.5A） Fig.23 Load Response Characteristics （Io=3A→0A） www.rohm.com ○ 2010 ROHM Co., Ltd. All rights reserved. c Gain ...

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... BD9859EFJ ●Evaluation Board Pattern (Reference) ・ Please make the Heat radiation plate of the Bottom layer to a plane of Low Impedance. ・ Because large currents low into the lines of VCC, Lx, PGND, please make the patterns as thick as much as possible. www.rohm.com ○ 2010 ROHM Co., Ltd. All rights reserved. ...

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... BD9859EFJ ●Application Components Selection Method (1)Inductor Something of the shield Type that Fulfills the Current Rating (Current value Ipecac below), with low DCR (Direct Current Resistance element) is recommended. Value of Inductor influences Inductor Ripple Current and becomes the cause of Output Ripple. In the same way as the formula below, this Ripple Current can be made small for as big as the L value of Coil or as high as the Switching Frequency. Ipeak =Iout ＋ ...

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... BD9859EFJ (5)About Adjustment of DC/DC Comparator Frequency Characteristics Role of Phase compensation element CC1､CC2,RC (See P.7Example of Reference Application Circuit) Stability and Responsiveness of Loop are controlled through VC Pin which is the output of Error Amp. The combination of zero and ball that determines Stability and Responsiveness is adjusted by the combination of resistor and capacitor that are connected in series to the VC Pin ...

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... BD9859EFJ Selection method of Phase Compensation constant is shown below. 1. Phase Compensation Resistor (RC) is selected in order to set to the desired Cross-over Frequency. Calculation done using the formula below.  2 COUT π  RC  GEA Here the desired Cross-over Frequency made about 1/20 and below of the Normal Switching Frequency (fs). ...

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... BD9859EFJ ●I/O Equivalent Schematic Pin. Pin Pin Equivalent Schematic No Name GND 6 BST 7 VCC 8 VCC VCC GND www.rohm.com ○ 2010 ROHM Co., Ltd. All rights reserved. c Pin. Pin Pin Equivalent Schematic No Name VCC GND VCC GND 13/15 Technical Note 2010.02 - Rev.A ...

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... BD9859EFJ ●Cautions for Use (1)About Absolute Maximum Rating When the absolute maximum ratings of application voltage, operating temperature range, etc. was exceeded, there is possibility of deterioration and destruction. Also, the short Mode or open mode, etc. destruction condition cannot be assumed. When the special mode where absolute maximum rating is exceeded is assumed, please give consideration to the physical safety countermeasure for the fuse, etc ...

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... BD9859EFJ ●ORDER MODEL NAME Device Debice Name MSOP8 2.9±0.1 (MAX 3.25 include BURR) + 6° 4° −4° 1PIN MARK +0.05 0.145 −0.03 0.475 S +0.05 −0.04 0.22 0.08 S 0.65 (Unit : mm) www.rohm.com ○ 2010 ROHM Co., Ltd. All rights reserved Package type HFN : HTSOP-J8 < ...

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