3ch DC/DC for TFT LCD
The R1290 series are the optimized DC/DC converter ICs for TFT LCD displays. Each of the R1290 series contains one PWM step-up DC/DC converter controller and two diode charge-pump controllers. The charge-pumps can control a boost output and a negative output and have the output voltage regulation function with external resistors.
The power on sequence can be made with setting the delay time with external capacitors for each charge pump channel. |
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 Operating Voltage Range |
2.0V to 5.5V |
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Step-up DC/DC controller part
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Internal 2A capability Nch MOSFET Driver （Ron=150mΩ Typ.）
Over Current Protection Function
Adjustable VOUT up to 20V with external resistors
Adjustable Phase compensation with external components
Max duty adjustable with external resistors for DTC pin
Soft-start time adjustable with external capacitor for SS pin
Oscillator Frequency：Adjustable frequency with resistors（180kHz～1400kHz） |
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Charge-pump part
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Adjustable output voltage with external resistors
| Sequence function: |
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Sequence function: Charge-pump turns on after the main step-up converter voltage outputs. The positive charge-pump and the negative charge-pump turn on sequence control is possible with setting delay time for each channel |
| Oscillator Frequency: |
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1/4 of the main step-up DCDC converter oscillator frequency |
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Controller part
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Under Voltage Lock-Out (UVLO: selectable detector threshold from 1.8V, 2.2V or 2.8V)
Reference voltage (VREF: Typ.1.2V)
| Short Protection with timer latch function (adjustable delay time with external capacitor): |
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Shutdown all the outputs if at least one of three outputs is short to the GND. |
Stand-by function by CE pin
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| Package |
Thin 24-pin Package QFN24 |
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Constant Voltage Power Source for LCD and CCD.
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| * All PDF files are less than 1MB unless otherwise stated. |
| * If you don't have Adobe Reader, you can download free. |
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Technical Info.
Technical Information on Ricoh Power Management ICs.
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Product Catalog
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| Selection guide is available for download in PDF format. |
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Non-promotion / Discontinued Products
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R1290 Series
