Features: Input voltage range from 5.5V to 28V
Forced-PWM or Pulse-skip modes
Lossless bottom-side FET current sensing
Adaptive duty cycle clamping
High current N-channel FET drivers
Low shutdown supply currents
Reference voltage accurate to within ±1.5%
Output voltage adjustable down to 0.6V
Power Good flag and Chip Enable
Under-voltage lockout
Over-voltage/Under-voltage protection
n Soft-start and Soft-shutdown
n Switching frequency adjustable 200kHz-500kHzApplicationNotebook Chipset Power Supplies
Low Output Voltage High Efficiency Buck RegulatorsPinout
Specifications
| Output Current |
16000 mA |
| Input Min Voltage |
5.5 Volt |
| Input Max Voltage |
28 Volt |
| Feedback Voltage |
0.6 Volt |
| Feedback Tolerance |
1.5 % |
| Frequency Min |
200 kHz |
| Frequency Max |
500 kHz |
| Output Range |
0.6V min |
| Adj Switch Frequency |
Yes |
| Adjustable Output |
Yes |
| Synchronous Rectification |
Yes |
| On/Off Pin |
Yes |
| Error Flag |
Yes |
| SoftStart |
Yes |
| Sync Pin |
No |
| Inverting |
No |
| Flyback |
No |
| Lossless Current Sense |
Yes |
| RegType |
Switching Controller |
| Temperature Min |
-5 deg C |
| Temperature Max |
125 deg C |
| Channels |
1 Channels |
| Special Features |
Selectable pulse-skip mode for high efficiency at light load |
| Topology |
Synchronous Buck |
| PWM Mode |
Voltage |
| Step-Down |
Yes |
| Step-Up |
No |
| Multiple Output Capability |
No |
| Output Min |
0.6 Volt |
| View Using Catalog |
Voltages from the indicated pins to SGND/PGND unless
otherwise indicated (Note 2): |
VIN
V5
VDD
BOOT
BOOT to SW
SW
ILIM
SENSE, FB
PGOOD
EN
Power Dissipation (TA = 25°C)
(Note 3) |
-0.3V to 30V
-0.3V to 7V
-0.3V to 7V
-0.3V to 36V
-0.3V to 7V
-0.3V to 30V
-0.3V to 30V
-0.3V to 7V
-0.3V to 7V
-0.3V to 7V
0.75W |
DescriptionThe LM27241 is an adjustable 200kHz-500kHz single channel voltage-mode controlled high-speed synchronous buck regulator controller. It is ideally suited for battery powered applications such as laptop and notebook computers. The LM27241 requires only N-channel FETs for both the upper and lower positions of the synchronous 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 resistor 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 input voltage range is 5.5V to 28V while the output voltage is 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, soft-shutdown and enable.
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
| LM27241MTC |
ABCD150 |
0 |
31520 |
0 |
0 |
3739000 |
1 |
1060951459 |
| LM27241MTCX |
ABCD150 |
0 |
31520 |
0 |
0 |
3739000 |
1 |
1060951459 |
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.
The LM27241 is an adjustable 200kHz-500kHz single channel voltage-mode controlled high-speed synchronous buck regulator controller. It is ideally suited for battery powered applications such as laptop and notebook computers. The LM27241 requires only N-channel FETs for both the upper and lower positions of the synchronous stage. It features line feedforward to improve the response to input transients. At very light loads, the user can choose between the highefficiency Pulse-skip mode or the constant frequency Forced-PWM mode. Lossless current limiting without the use of external sense resistor 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 input voltage range is 5.5V to 28V while the output voltage is 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, soft-shutdown and enable.
LM27241 Data Sheet
