TPS5430 vs TPS5450 - Which SWIFT Buck Converter Should You Pick?

At a Glance

What Are the Real Differences?

Let's be honest - these two chips are nearly identical. They use the same controller, the same package, the same pinout. The main difference is the size of the internal MOSFET:

1. Output Current - The Only Real Difference

The TPS5450 uses a larger high-side N-channel MOSFET to handle 5A continuous (6A peak) vs the TPS5430's 3A (4A peak). Everything else - control loop, protection features, switching behavior - is essentially the same.

But here's something worth noting: the Rds(on) on the TPS5430 is actually slightly lower than the TPS5450 (100 mΩ vs 110 mΩ). That means at the same load current, the TPS5430 will dissipate slightly less power. The TPS5450's MOSFET is bigger to handle higher current, not to be more efficient at low current.

2. Pin Compatibility - The Killer Feature

They are drop-in compatible. Same footprint, same pinout, same external component values for the same output voltage. You can design your PCB with a TPS5430, test it, and swap to a TPS5450 if you need more current. No board spin required.

From our experience helping customers with sourcing, this is the main reason engineers pick this family over newer, higher-performing parts - the flexibility to scale current without requalifying a board layout.

3. Negative Voltage Output

The TPS5430 officially supports inverting buck-boost topology (positive to negative voltage conversion). The TPS5450 does not list this in its datasheet, though some users on the TI E2E forum have reported it working. If you need a negative rail, go with the TPS5430.

When to Pick Each

Design Considerations for Both

Same external components work for both - that's the beauty of pin compatibility. A 15 μH inductor, 100 μF output cap, and the same feedback resistor divider work for either chip at 5V output.

But there are a couple things to watch:

• Inductor saturation: If you're designing for the TPS5430 but might swap to the TPS5450 later, spec the inductor for 5A peak from day one. A 3.5A-rated inductor that works fine for the 5430 will saturate with the 5450's higher current limit.
• Thermal: At 5A output, the TPS5450 dissipates more power than the 5430 at 3A. Make sure your PowerPad soldering and copper pour are designed for the worst case. From what we see in the TI E2E forums, poor thermal pad soldering is the #1 cause of field failures on both chips.
• Input capacitor: Both chips need a low-ESR ceramic cap right at VIN and GND. This is non-negotiable - skip it and you risk destroying the chip on first power-up.

Frequently Asked Questions

Q1: Can I drop a TPS5450 into a board designed for TPS5430?

A: Yes. Same pinout, same package, same footprints. You need to check two things: the inductor must be rated for the higher peak current, and the PCB copper must handle the higher thermal dissipation. Otherwise it's a straight swap.

Q2: What's the price difference?

A: At 1k quantity, the TPS5430 runs about $2.00 and the TPS5450 about $2.80 - roughly 40% more. At volume (10k+), the gap narrows to about 20-30%.

Q3: Which one runs cooler at the same load?

A: The TPS5430. Its Rds(on) is 100 mΩ vs the TPS5450's 110 mΩ, so at the same current the 5430 dissipates slightly less power. But the difference is small - we're talking about 0.25W less at 5A.

Q4: Can the TPS5450 do negative voltage output like the TPS5430?

A: Not officially documented. Some users on TI's E2E forum have reported it working, but TI doesn't guarantee it. If you need a negative rail, stick with the TPS5430.

Q5: Do I need different inductor values for each?

A: No, the same inductor value works for both at the same output voltage (15 μH for 5V, 22 μH for 12V, 10 μH for 3.3V in both). But the TPS5450 needs a higher saturation current rating.

Q6: What's the catch diode recommendation for each?

A: For the TPS5430 at 3A, a 3A Schottky like the MBR360 or SS36 is sufficient. For the TPS5450 at 5A, step up to a 5A-rated Schottky like the MBR560. The diode conducts during the off-time, so its rating must match the output current.

Q7: Are the TPS54340 and TPS54540 better choices?

A: The 54340/54540 parts handle up to 42V or 60V input, which gives you more headroom for automotive transients. They also have higher switching frequencies (up to 2.5 MHz). But they're more expensive and not pin-compatible with the 5430/5450. Pick the 340/540 series if you need higher input voltage or smaller inductor size.

Q8: Which one is more commonly available?

A: Both are widely stocked. From our sourcing experience, the TPS5450 can have longer lead times during supply crunches.

Pricing & Availability

Contact ICMASS for current pricing. Both parts available in original TI packaging with full traceability. We can also advise on which one fits your specific load requirements.