SLVUC68 September 2021 TPSM5601R5H
Stability is an important factor in power converters. The guideline for a stable design is a phase margin of at least 45°. With that in mind, the TPSM5601R5H-IBB-EVM is designed to accommodate a wide range of operating conditions with a phase margin greater than 45°. Note that the stability of the system (EVM) will be affected by the operating conditions, input voltage, and total output capacitance. Figure 5-6 demonstrates the recommended operating range for a stable design (≥ 45°). If the operating conditions are outside the recommended range, it is important to run a bode plot to ensure stability.
Table 5-1 shows the phase margin across various input voltages with a fixed –5-V output. The results measured are from the original BOM (COUT = 2 × 47 μF) of the TPSM5601R5H-IBB-EVM.
| VIN (V) | VOUT (V) | Max IOUT (A) | Fcrossover (kHz) | PHASE MARGIN (°) |
|---|---|---|---|---|
| 12 | –5 | 0.982 | 18.00 | 45.0 |
| 24 | –5 | 1.184 | 23.30 | 50.8 |
| 28 | –5 | 1.221 | 24.32 | 51.7 |
| 36 | –5 | 1.271 | 26.00 | 53.2 |
| 48 | –5 | 1.315 | 27.40 | 54.3 |