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Rating |
Catalog |
Topology |
Buck Controller |
Iout (max) (A) |
4 |
Vin (max) (V) |
35 |
Vin (min) (V) |
4.5 |
Vout (max) (V) |
35 |
Vout (min) (V) |
1.239 |
Control mode |
Hysteretic |
Features |
Enable |
Duty cycle (max) (%) |
100 |
Iq (typ) (A) |
0.00028 |
Number of phases |
1 |
Operating temperature range (°C) |
-40 to 125 |
VSSOP (DGK)-8-14.7 mm² 3 x 4.9
The LM3489 device is a high-efficiency PFET switching regulator controller that can be used to quickly and easily develop a small, cost-effective, switching buck regulator for a wide range of applications. The hysteretic control architecture provides for simple design without any control loop stability concerns using a wide variety of external components. The PFET architecture also allows for low component count as well as ultra-low dropout, 100% duty cycle operation. Another benefit is high efficiency operation at light loads without an increase in output ripple. A dedicated enable pin provides a shutdown mode drawing only 7 µA. Leaving the enable pin unconnected defaults to on.
Current limit protection can be implemented by measuring the voltage across the PFETs RDS(ON), thus eliminating the need for a sense resistor. A sense resistor may be used to improve current limit accuracy if desired. The cycle-by-cycle current limit can be adjusted with a single resistor, ensuring safe operation over a range of output currents.