TPS5450 Step-Down Module

TPS5450 is a step-down switching power supply chip from Texas Instruments with wide voltage input (5.5V-36V), wide voltage output, high current 5A output, peak current up to 6A, low ripple, overvoltage, overheating, overcurrent protection, switching frequency 500KHZ, efficiency up to 90%, etc. The TPS5450 power module is equipped with 12V 9V 5V 3.3V output. The components use precision resistors. The output can be relatively stable.
This is the ripple of 12V input 5V output when it is unloaded, and the ripple is within 5mv. The output ripple can be changed by changing the values ​​of input capacitor, output capacitor, freewheeling diode, feedforward and feedback capacitor. At the beginning of the test, the output ripple was too large, so the 100pf feedforward and feedback capacitors were changed to 1.5NF, and the ripple was reduced from the initial 100MV to 20MV. At this time, the ripple was still very high, and there were many burrs. After thinking about it, it might be caused by the freewheeling diode, so the initial B540C freewheeling diode was changed to MCC SK1045 freewheeling diode, and the burrs were much smaller as shown below. The main function of the freewheeling diode is to improve the conversion efficiency of the power supply.
This is the ripple at 3.3V output. The ripple does not exceed 5mv, and the voltage difference of the secondary module exceeds 0.5V to work normally.
With a 5A load, the output ripple does not exceed 15mv, which meets half of the occasions. The ENA pin can be used to control the output shutdown. When the circuit is suspended, it works normally, which is practical for single-chip microcomputer control slow start. Since there is no load meter, other items were not tested. The performance of TPS5450 is far superior to that of mps2236.
Note: For the input power supply voltage, use high-quality, low-ESR ceramic capacitors. Even if one capacitor is missing in this module, it will not work. Don't ask why it won't work, because I have measured it myself, and one less capacitor will also cause the output ripple to have many spikes and glitches, which is several times the normal ripple. If you don't believe it, you can try it. The model of D1 is MCC SK1045, which cannot be replaced at will. If you replace it, please choose a diode with a reverse voltage of 40V, a forward current of 5A and a forward voltage drop of 0.5V.
The total price of the module is about 15 yuan.