Datasheet
Package Availability, Models, Samples & Pricing
General Description
The LM2657 is an adjustable 200kHz-500kHz dual channel voltage-mode controlled high-speed synchronous buck regulator controller ideally suited for high current applications. The LM2657 requires only N-channel FETs for both the upper and lower positions of each stage. It features line feedforward to improve the response to input transients. At very light loads, the user can choose between the high-efficiency Pulse-skip mode or the constant frequency Forced-PWM mode. Lossless current limiting without the use of external sense resistors is made possible by sensing the voltage drop across the bottom FET. A unique adaptive duty cycle clamping technique is incorporated to significantly reduce peak currents under abnormal load conditions. The two independently programmable outputs switch 180° out of phase (interleaved switching) reducing the input capacitor and filter requirements. The input voltage range is 4.5V to 28V while the output voltages are adjustable down to 0.6V.
Standard supervisory and control features include Soft-start, Power Good, output Under-voltage and Over-voltage protection, Under-voltage Lockout, and chip Enable.
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
|
LM2657MTC | ABCD150 | 0 | 34175 | 0 | 0 | 4234000 | 1 | 1201409060
|
|
LM2657MTCX | ABCD150 | 0 | 34175 | 0 | 0 | 4234000 | 1 | 1201409060
|
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 - Reducing Buck Converter Input Capacitance through Multi-Phasing and Clock Synchronization |
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| Article - Robust Controller Design Using Multi-Objective Optimization |
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[Information as of 7-Nov-2009]
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RoHS Compliance Information
