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參數(shù)資料
| 型號： | R1221N28AA |
| 廠商： | Ricoh Co., Ltd. |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | Voltage-Mode SMPS Controller |
| 中文描述： | 電壓模式開關(guān)電源控制器 |
| 文件頁數(shù)： | 1/21頁 |
| 文件大小： | 218K |
| 代理商： | R1221N28AA |
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Step-down DC/DC Converter with Voltage Detector
R1221N Series
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99.12.8
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Rev. 1.11 - 1 -
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OUTLINE
The R1221N Series are PWM step-down DC/DC Converter controllers embedded with a voltage detector, with
low supply current by CMOS process.
Each
step-down DC/DC converter in these ICs consists of an oscillator, a PWM control circuit, a reference
voltage unit, an error amplifier, a soft-start circuit, a protection circuit, a PWM/VFM alternative circuit, a chip
enable circuit, and resistors for voltage detection. A low ripple, high efficiency step-down DC/DC converter can be
composed of this IC with only four external components, or a power-transistor, an inductor, a diode and a
capacitor.
The output voltage of DC/DC converter can be supervised by the built-in voltage detector.
With a PWM/VFM alternative circuit, when the load current is small, the operation turns into the VFM oscillator
And the PWM/VFM alternative circuit is an option, in terms of C version and D version, the circuit is not included.
If the term of maximum duty cycle keeps on a certain time, the embedded protection circuit works. There are two
types of protection function. One is latch-type protection circuit, and it works to latch an external Power MOS with
keeping it disable. To release the condition of protection, after disable this IC with a chip enable circuit, enable it
again, or restart this IC with power-on. The other is Reset-type protection circuit, and it works to restart the
operation with soft-start and repeat this operation until maximum duty cycle condition is released. Either of these
protection circuits can be designated by users’ request.
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FEATURES
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Wide Range of Input Voltage
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2.3V to 13.2V
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Built-in Soft-start Function and two choices of Protection Function(Latch-type or Reset-type)
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Two choices of Oscillator Frequency
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300kHz, 500kHz
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High Efficiency
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TYP. 90%
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Standby Current
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TYP. 0μA
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Setting Output Voltage
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Stepwise setting with a step of 0.1V in the range of
1.5V to 5.0V
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High Accuracy Output Voltage
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±2.0%
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Setting Detector Threshold Voltage
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Stepwise setting with a step of 0.1V in the range of
1.2V to 4.5V
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High Accuracy Detector Threshold Voltage
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±2.0%
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Low Temperature-Drift Coefficient of Output Voltage
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TYP. ±100ppm/
°
C
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APPLICATIONS
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Power source for hand-held communication equipment, cameras, video instruments such as VCRs,
camcorders.
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Power source for battery-powered equipment.
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Power source for household electrical appliances.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| R1221N28AA-TR | Voltage-Mode SMPS Controller |
| R1221N28AB | Voltage-Mode SMPS Controller |
| R1221N28AB-TR | Voltage-Mode SMPS Controller |
| R1221N28AC | Voltage-Mode SMPS Controller |
| R1221N29AA | Voltage-Mode SMPS Controller |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| R1221N28AA-TR | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Voltage-Mode SMPS Controller |
| R1221N28AB | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Voltage-Mode SMPS Controller |
| R1221N28AB-TR | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Voltage-Mode SMPS Controller |
| R1221N28AC | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Voltage-Mode SMPS Controller |
| R1221N28AC-TR | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Voltage-Mode SMPS Controller |
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