Bill Betz
Executive Vice President and Chief Financial Officer at NXP Semiconductors
Thank you, Kurt. And good morning to everyone on today's call. As Kurt has already covered the drivers of the revenue during Q1 and provided our revenue outlook for Q2, I will move to the financial highlights.
Overall, the Q1 financial performance was good. Revenue was in line with the midpoint of our guidance range with non-GAAP gross margin slightly above the midpoint of our guidance, while inventory in the distribution channel continues to remain below our long-term target.
Turning to Q1 results, total revenue was $3.13 billion, flat year-on-year, in line with the midpoint of our guidance range. We generated $1.82 billion in non-GAAP gross profit and reported a non-GAAP gross margin of 58.2%, flat year-on-year, though 20 basis points above the midpoint of our guidance range.
The incremental margin was due to an increase in the estimated useful lives of our internal front-end manufacturing equipment from 5 to 10 years. This was about 30 basis points favorable to the results, which was not in our guidance.
Total non-GAAP operating expenses were $736 million or 23.5% of revenue, up $8 million year-on-year, and down $55 million from Q4. This was $19 million below the midpoint of our guidance range, primarily due to a combination of reduced variable compensation and proactive expense control.
From a total operating profit perspective, non-GAAP operating profit was $1.08 billion and non-GAAP operating margin was 34.5%, down 30 basis points year-on-year and 60 basis points above the midpoint of our guidance range.
Non-GAAP interest expense was $64 million, with taxes for ongoing operations of $171 million or a 16.8% non-GAAP effective tax rate. Non-controlling interest was $5 million and stock-based compensation, which is not included in our non-GAAP earnings, was $115 million.
Now I would like to turn to the changes in our cash and debt. Our total debt at the end of Q1 was $10.18 billion, down $997 million as we repaid the 4.875% bond that was due on March 1, 2024. Our ending cash balance, including short-term deposits, was $3.31 billion, down $963 million sequentially due to the cumulative effect of debt repayment, capital returns, capex investments, and cash generation during Q1.
The resulting net debt was $6.9 billion, and we exited the quarter with a trailing 12-month adjusted EBITDA of $5.4 billion. Our ratio of net debt to trailing 12-month adjusted EBITDA at the end of Q1 was $5.4 was 1.3 times, and our 12-month adjusted EBITDA interest coverage ratio was 22.8 times.
During Q1, we paid $261 million in cash dividends, and we repurchased $303 million of our shares. Subsequent to the end of Q1 and through Friday, April 26, we repurchased an additional under an established 10b5-1 program.
Turning to working capital metrics, days of inventory was 144 days, an increase of 12 days sequentially, while distribution channel inventory was 1.6 months or about 7 weeks. As we have highlighted throughout the previous year, given the uncertain demand environment, we continued to make the intentional choice to limit inventory in the channel while keeping inventory on our balance sheet to enable greater flexibility to redirect product as needed.
Days receivables were 26 days, up 2 days sequentially, and days payable were 65 days, a decrease of 7 days versus the prior quarter. Taken together, our cash conversion cycle was 105 days, an increase of 21 days versus the prior quarter.
Cash flow from operations was $851 million and net capex was $224 million or approximately 7% of revenue, resulting in non-GAAP free cash flow of $627 million or about 20% of revenue.
Turning now to our expectations for the second quarter. As Kurt mentioned, we anticipate Q2 revenue to be $3.125 billion, plus or minus about $100 million. At the midpoint, this is down 5% year-on-year and flat sequentially. We expect non-GAAP gross margin to be about 58.5%, plus or minus 50 basis points, which includes approximately 60 basis points associated with the change of our useful life estimate for our internal front-end manufacturing equipment.
As Kurt noted in his prepared remarks, we will begin to stage slightly higher inventory in the channel to support our competitiveness for the anticipated second half growth. Therefore, our guidance assumes approximately 1.7 months of distribution channel inventory exiting Q2.
Operating expenses are expected to be about $765 million, plus or minus about $10 million. The sequential increase is primarily driven by our annual merit increases and the $15 million license fee paid to impinge as part of our legal settlement. Taken together, we see non-GAAP operating margin to be 34% at the midpoint.
We estimate non-GAAP financial expense to be $63 million, with the non-GAAP tax rate to be 16.8% of profit before tax. Non-controlling interest and other will be about $5 million.
For Q2, we suggest, for modeling purposes, you use an average share count of 258.5 million shares. We expect stock-based compensation, which is not included in our non-GAAP guidance, to be $115 million. For capital expenditures, we expect to be around 6%.
Taken together at the midpoint, this implies a non-GAAP earnings per share of $3.20.
In closing, looking through the remainder of 2024, I'd like to highlight a few focus areas for NXP. First, from a performance standpoint, we will continue to navigate a soft landing through a challenging and cyclical demand environment with a cautious optimism for a second half improvement in our business.
Second, we will continue to be disciplined to manage what is in our control and stay within our long-term financial model. Specifically, we expect our gross margin will continue to perform at or above the high end of the long-term model, while maintaining internal fab utilization levels in the low 70s for the remainder of the year.
Third, there is no change to our capital allocation policy, where we have returned $2.4 billion over the last 12 months. Furthermore, we will continue to be active in the market repurchasing NXP shares.
And lastly, we are excited to host an Investor Day on November 7th in Boston. The specific details will be available soon on the NXP Investor Relations homepage. We look forward to you joining us.
I'd like to now turn it back to the operator for questions.