PWM/VFM Step-Down DC/DC Converter
The R1224N Series are CMOS-based PWM step-down DC/DC Converter controllers with low
supply current.
Each of these ICs consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier,
a phase compensation circuit, a soft-start circuit, a protection circuit, a PWM/VFM alternative circuit, a chip
enable circuit, resistors for output voltage detect, and input voltage detect circuit. A low ripple, high efficiency
step-down DC/DC converter can be easily composed of this IC with only several external components, or a power-transistor,
an inductor, a diode and capacitors. Output Voltage is fixed or can be adjusted with external resistors (Adjustable
types are without PWM/VFM alternative circuit).
With a PWM/VFM alternative circuit, when the load current is small, the operation is automatically switching
into the VFM oscillator from PWM oscillator. Therefore, the efficiency at small load current is improved. Several
types of the R1224Nxxx, which are without a PWM/VFM alternative circuit, are also available.
If the term of maximum duty cycle keeps on a certain time, the embedded protection circuit works. The protection
circuit 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. When the cause of large load current or something else
is removed, the operation is automatically released and returns to normal operation.
Further, built-in UVLO function works when the input voltage is equal or less than UVLO threshold, it makes this
IC be standby and suppresses the consumption current and avoid an unstable operation. |
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 Supply
Current |
| Typ. 20µA (R1224Nxx2E/F/M/L, R1224N102M) |
| Typ. 30µA (R1224Nxx2G, R1224N102G) |
| Typ. 40µA (R1224Nxx2H, R1224N102H) |
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| Standby
Current |
TYP. 0µA |
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| Input
Voltage Range |
2.3V~18.5V |
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| Output
Voltage Range
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| 1.2V to 6.0V (R1224Nxx2x) |
| 1.0V to VIN (R1224N102x) |
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| Output
Voltage Accuracy |
±2.0% |
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| Oscillator
Frequency |
| Typ. 180kHz (R1224Nxx2M, R1224N102M) |
| Typ. 300kHz (R1224Nxx2E/G, R1224N102G) |
| Typ. 500kHz (R1224Nxx2F/H, R1224N102H) |
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| Efficiency |
Typ.. 90% |
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| Low
Temperature-Drift Coefficient of Output Voltage |
TYP. ±100ppm/°C |
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| Package |
SOT-23-5 |
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| Built-in
Soft-start Function |
Typ. 10ms |
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| Built-in
Current Limit Circuit |
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Data Sheet
(PDF) |
Package Info.
(PDF) |
Mark Info.
(PDF) |
Quality Assurance Data
(PDF) |
 R1224N
Series
EA-096-061102(871KB) |
SOT-23-5 |
R1224N |
to be prepared |
to be prepared |
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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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