R1218 Series
PWM Step-up DC/DC Converter for White LED
Description
The R1218 Series are CMOS-based PWM step-up DC/DC converters, which are optimized to drive white LEDs with constant current. R1218 includes an under-voltage lockout circuit (UVLO), over-voltage protection circuit (OVP). By simply using an inductor, a resistor, and a capacitor (, a diode) as external components, white LEDs can be driven with constant current efficiency. R1218Nxx1A for 2 to 4 lights contains an internal diode while R1218Nxx2A for 5 to 7 lights requires an external diode. The LED current can be determined by the value of current setting resistor. The brightness of the LEDs can be adjusted by applying a PWM signal to the CE or VFB pin.
Spec
| Standard | |
|---|---|
| Input Voltage Range | 1.8 V to 5.5 V (6.5 V) |
| Operating Temperature Range | -40°C to 85°C (125°C) |
| Supply Current | Typ. 500 µA |
| Standby Current | Typ. 0 µA |
| Output Voltage Range | Externally Adjustable: Max. 30 V |
| Feedback Voltage | Typ. 0.2 V |
| Feedback Voltage Accuracy | ±10 mV |
| Oscillator Frequency | Typ. 1.2 MHz |
| Maximum Duty Cycle | Typ. 91 to 92% |
| Package | SOT-23-6 |
Protections / Functions
| TSD | OCP | OVP | UVLO | OVLO | Reverse | Shutdown | Soft Start | SSCG | PGOOD | Auto Discharge | Anti-ringing | Sequencing | Max Duty | Ext. Phase | LED Adjust |
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Functional Description
| TSD | Thermal Shutdown Function |
|---|---|
| OCP | Overcurrent Protection Note: The function previously labeled as "ILX (LX Current Limit Function)" is now shown as "OCP." |
| OVP | Overvoltage Protection |
| UVLO | Undervoltage Lockout Protection |
| OVLO | Overvoltage Lockout Protection |
| Reverse | Reverse Current Protection Circuit |
| Shutdown | Shutdown Function |
| Soft Start | Soft Start Function |
| SSCG | Spread Spectrum Clock Generator Function |
| PGOOD | Power Good Output |
| Auto Discharge | Auto Discharge Function |
| Anti-ringing | Anti-ringing Switch Function |
| Sequencing | Start-up Sequencing Control |
| Max Duty | Maximum Duty Cycle |
| Ext. Phase | Externally Adjustable Phase Compensation |
| LED Adjust | LED High-speed Dimming Control |
Technical Documents
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R1218N041A Typical Application
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R1218N072A Typical Application
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R1218N041A Efficiency vs. Output Current
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Related Links
Quality & Packages
- Refer to the datasheets for the details on the product.
- The package file or the datasheet includes package dimensions, taping specifications, taping reels dimensions, power dissipations, and recommended land pattern.
FAQ
Buy / Contact
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Purchase, Request for samples and documentsSales are made through distributors. Please contact your local distributors for any sales-related inquiry such as price.
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Available from 1 piece!Our electronic device products are available through our authorized online distributors.
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Technical Support