Datasheet
RoHS Compliance Information
| Size in Kbytes | Date |
 |
| LM27952 White LED Adaptive 1.5X/1X Switched Capacitor Current Driver |
660
Kbytes |
9-Sep-05 |
Download |
LM27952 White LED Adaptive 1.5X/1X Switched Capacitor Current Driver (Japanese)
 |
437 Kbytes |
|
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Package Availability, Models, Samples & Pricing
General Description
The LM27952 is a switched capacitor white-LED driver capable of driving up to 4 LEDs with 30mA through each LED. Its 4 tightly regulated current sinks ensure excellent LED current and brightness matching. LED drive current is programmed by an external sense resistor. The LM27952 operates over an input voltage range from 3.0V to 5.5V and requires only four low-cost ceramic capacitors.
The LM27952 provides excellent efficiency without the use of an inductor by operating the charge pump in a gain of 3/2, or in a gain of 1. Maximum efficiency is achieved over the input voltage range by actively selecting the proper gain based on the LED forward voltage requirements.
The LM27952 uses constant frequency pre-regulation to minimize conducted noise on the input. It has a fixed 750kHz switching frequency optimized for portable applications. The LM27952 consumes less than 1µA of supply current when shut down.
The LM27952 is available in a 14-pin No-Pullback Leadless Leadframe Package: LLP-14.
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
|
LM27952SD | CMOS7 | 0 | 18406 | 0 | 0 | 1089000 | 4 | 309006723
|
|
LM27952SDX | CMOS7 | 0 | 18406 | 0 | 0 | 1089000 | 4 | 309006723
|
Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR.
The Long Term Failure Rates were calculated
at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress
temperature of 150°C to an application temperature of 55°C.
For more information on Reliability Metrics, please click here.
Design Tools
| Title | Size in Kbytes |
Date |
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| Article - Want to Boost Battery Voltage in White LED Apps? |
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View |
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More Application Notes
| Title | Size in Kbytes |
Date |
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| AN-1218: Application Note 1218 LM2791/2/4/5 Evaluation Board |
424
Kbytes |
13-May-04 |
Download |
| AN-1251: Application Note 1251 Switched Capacitor Circuits Provide Efficient and Functional White LED Drive |
55
Kbytes |
26-Sep-02 |
Download |
[Information as of 8-Nov-2009]
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