Ladies and gentlemen, thank you for standing by, and welcome to the Allegro Microsystems 2Q Fiscal 2021 Financial Results Conference Call. At this time, all participants are in a listen only mode. Please be advised that today's conference may be recorded. I would now like to hand the conference over to your speaker today, Ms. Katie Blythe, Senior Director of Investor Relations.
Thank you. Please go ahead.
Good morning, and thank you for joining us today for Allegro's 2nd quarter results for fiscal year 2021. I'm joined today by Allegro's President Chief Executive Officer, Ravi Vig and Allegro's Chief Financial Officer, Paul Walsh. We'll review our quarterly financial performance and provide a summary of our outlook. Our earnings release and the accompanying financial tables are available on the Investor Relations page of our website. This call is being web tested and a recording will be available on our IR page shortly.
Please note that comments made during this conference call include forward looking statements within the meaning of federal securities laws. These forward looking statements include projections and other statements about future events that are based on current expectations and assumptions and as a result are subject to risks and uncertainties that could cause actual results to vary materially from our projections. Please refer to the earnings press release we issued today and other documents filed by us with the SEC, including the risk factors discussed in detail in our final IPO prospectus filed on October 30, 2020. The company assumes no obligation to update any forward looking information presented. The non GAAP financial measures that are discussed today are not intended to replace or be a substitute for the presentation of Allegro's GAAP financial results and may be calculated differently than similar measures used by other companies.
We are providing this supplemental information because it may enable investors to make meaningful comparisons of core operating results and more clearly highlight the results of our core ongoing operations. A reconciliation of GAAP to non GAAP financial measures referenced during today's call can be found in the tables provided in our earnings press release and posted to our IR page. I'll now turn the call over to Allegro's President and CEO, Ravi Zeig. Ravi?
Thank you, Katie, and good morning, everyone. Revenue in fiscal Q2 exceeded our expectations and demonstrated strong recovery of our COVID quarter's lows. Our revenue grew $21,000,000 or approximately 19% on a sequential basis to $136,600,000 flat with the prior year, as a result of strength across all end markets. We're forecasting healthy sequential growth again for our fiscal Q3 with revenues of $149,000,000 plus or minus 2,000,000 dollars Our automotive business has benefited from the global automotive production rebound with solid upside as automakers came back online. We also benefited from ramping wins in XEV, which we expect to accelerate as many automakers have recently presented plans that further bias vehicle lineups towards XEV powertrains.
And our ADAS story continues to strengthen with our latest wins increasing our total content per vehicle in advanced safety critical steering and braking applications. Last quarter, we closed on our acquisition of VoxDell, a developer of photonics components for LiDAR. The acquisition pairs leading eye safe photonics technology with our extensive portfolio of products optimized for ADAS applications. Overall, it's important to remember that we believe we're positioned right in the sweet spot of the most significant trends in the auto market, giving us a good launch pad as the market recovers. Our industrial and other business also saw strength during the quarter.
We believe the industrial market and a growing portfolio of power and sensor products represent high quality growth vectors, and we continue to see healthy demand in factory automation and data center applications. Reinforcing our healthy outlook is the acceleration in customer bookings during the Q2, particularly in August September across all end markets. We believe our business recovery is shaping up and we are preparing for upside scenarios. I'll provide more color on our view of the current health and positive trajectory of our business after we review the financial results. Paul?
Thank you, Ravi. Net sales or revenue in fiscal 2Q of $136,600,000 was up 18.8% sequentially, rebounding strongly off a COVID impacted 1st quarter. We entered 2Q with a solid backlog and bookings continued to accelerate, particularly from our automotive customers. Our end market revenue mix for the quarter began to return to a more normal ratio. Automotive revenue was 89,500,000 dollars Industrial revenue was $21,700,000 and other was $25,500,000 for the quarter.
We did not have any end customers at 10% during the quarter. Our business is reasonably diverse even considering the market share we enjoy among Tier 1 automotive and industrial customers. Our GAAP gross margin for the quarter was 45.2 percent, 300 basis points higher than the same period a year ago. Consistent with our preliminary flash reporting in our IPO prospectus, our non GAAP gross margin was 47.7%, which does not include adjustments of approximately $3,000,000 for expenses related to the Thai facility consolidation and the one time adjustment for depreciation of GMR assets, as noted in our press release. We expect our non GAAP gross margins in 3Q to be in the range 50% to 51%, which also does not include the impact of these adjustments.
Total GAAP operating expenses decreased sequentially by $1,800,000 to $49,400,000 with R and D of $25,100,000 and SG and A of $24,200,000 Non GAAP operating expenses were $45,200,000 which does not include adjustments of $400,000 for expenses related to the Tide facility consolidation. These unique costs associated with our various transformational activities are not expected to be meaningful beyond fiscal 2021. We expect that non GAAP operating expenses will be up modestly in 3Q, mainly driven by variable compensation as our business continues to improve. GAAP operating income for the quarter was $12,400,000 or 9.1 percent of revenue. The fiscal 2Q effective tax rate was 17.8 percent and GAAP net income for the 2nd fiscal quarter was up sequentially to $9,600,000 Non GAAP operating income was $20,000,000 or 14.6 percent of revenue, which also does not include adjustments of approximately $3,400,000 related to the Thai facility consolidation and a one time adjustment for depreciation of GMR assets.
The 2Q non GAAP effective tax rate was approximately 15% and is expected to be 15% to 17% in fiscal 3Q. Our share count for the quarter as a private company was 10,000,000 but is not meaningful as a comparison to future periods. Our diluted share count for 3Q will be approximately 189,400,000 shares. We are not providing GAAP earnings per share guidance due to the impact of the following significant 3Q events not determinable at this point. These include the singular vesting event of pre IPO Class A shares held by employees and the issuances of new equity awards, each in connection with our IPO the planned retirement of at least 75 percent of a $325,000,000 term loan and the associated deferred financing costs a $400,000,000 dividend prior to our IPO and the tax consequences of each of these material events.
Our strong execution and business fundamentals continue to be evident in our balance sheet. Cash and equivalents of $208,000,000 in 2Q were down $12,000,000 sequentially, primarily due to the Voxtel acquisition and incentive payouts. Accounts receivable balances were $77,500,000 and we ended the quarter with DSO of 51 days, which was down 7 days compared to the Q1 and consistent with historical norms. Net inventory decreased by $3,000,000 as anticipated to finish at $105,000,000 Based on the information we have, we believe inventories in the channel are at desirable levels and end customer demand appears strong. In summary, we experienced a significant recovery in our top line during the quarter, exceeding our expectations.
We believe our operational efficiencies and balance sheet foundation are indicative of the strength in our underlying business. I'll now turn it back over to Ravi.
Thank you, Paul. It's great to see the positive results of the business transformation that we began 4 years ago. The transformation included strategic objectives that are visibly paying off. 1st, we focused on extending market leadership through targeted portfolio expansion. You will hear today about increased traction in XEV, ADAS, factory automation and data center applications.
2nd, we have been developing a more nimble manufacturing strategy to improve the operating model. The benefits of these actions are evident in the strong fiscal Q2 performance. Along with our top line recovery, we have seen continued momentum in our key sales metrics fiscal year to date with design wins up 20%. The vast majority of these design wins are for new business with a concentration in our target high growth applications. Some of the notable design win activity in the quarter included significant wins at a major Tier 1 for current sensors and XEV inverters.
We also secured wins for motor drivers and white goods programs in Korea and China, which we expect will ramp in the near term. As you know, we are the market leader in magnetic sensor ICs. We are focused primarily on the high value opportunities in the auto and industrial markets. Magnetic Sensor IC revenue represented 63% of revenue in fiscal Q2, growing 17% sequentially after the trough created by the COVID-nineteen pandemic. Our growth was driven by the recovery in automotive, particularly for speed and position sensors.
Power ICs were up 21% sequentially, representing 37% of revenue in fiscal Q2. We believe this growth was due in part to expanding content and systems where we already have an incumbent position with our sensors. And on that note, we recently announced our latest family of power products, the industry's largest portfolio of 80 volt motor drivers for advanced 48 volt automotive systems like battery electric and hybrid electric vehicles. These products provide world class safety diagnostics in ultra small packages, enabling smaller, more efficient designs. We already have great engagement on these products with Tier 1 customers globally, and we are leveraging our high voltage power expertise beyond automotive to industrial applications from 48 volt power inverters to e bikes.
Now let's take a closer look at our end markets, starting with automotive. Automotive represented 65% of our total revenue, down from historical levels in the lowtomid70s range. Q2 revenue grew 17% sequentially. Looking back to Q1, our automotive revenue did not decline as sharply as the overall automotive market due in part to a slow responding customer supply chain and a global diversification. This softened the impact of the production volume decline on our automotive sales in the Q1, but also created some pockets of inventory at our customers that we believe was subsequently depleted during Q2.
We do expect that inventories have balanced out and are at reasonable levels. Our auto revenue growth reflects a market recovery in our ICE, XEV, ADAS and Safety, Comfort and Convenience businesses, which all grew double digits in the 2nd quarter. Our revenue in XCV was up more than 35% sequentially and nearly 100% year over year, which speaks to the momentum in the space. We win when cars electrify and we're seeing our content per vehicle increase rapidly from battery chargers and inverters to battery cooling for XEV. Beyond those types of electrified powertrain applications, we are growing our XEV related content with our Quiet Motion family of fan drivers, power products and systems like in cabin heating and cooling, which now have to be quieter, more efficient and run off the battery.
We currently have programs ramping across a broad range of applications in XEB around the world and we expect to see double digit sequential growth again for the coming quarter. Another space where we are seeing our content opportunity increase is ADAS. In Q2, demand recovered in ADAS applications and our revenue was up 12% sequentially. We expect to see strong double digit growth in Q3. With our latest new program wins now ramping, we're increasing our overall content for our power products alongside our market leading sensors.
For example, one of our latest program wins for braking in Korea includes 4 of our magnetic sensor ICs and 2 power devices. Now, I'll cover our industrial business for Q2. This business consists of some of our strategic focus areas outside of automotive, such as Industry 4.0, Renewable Energy and Infrastructure, including data center. In Q2, our industrial business was up 6% sequentially and up 20% year over year as the business continues its transition to new growth markets. Our broad based category traditionally serviced through the distribution channel grew 10% sequentially as factories reopened and production accelerated.
Within our Industry 4.0 category, which makes up 7% of our revenue, building and factory automation was up double digits sequentially. Industry 4.0 continues to be a major focus area for us as we align our technologies with increasing applications demands for precision, efficiency and reliability. We've also been strategic about applying our power technology to take advantage of our disruptive trend in growth markets such as data centers converting to 48 volt and our customers are taking notice of that. We now count most of the hyperscale data center providers as our customers. This is an area that continues to offer diversification and augment growth for us.
In Q2, data center revenue was up in the high single digits sequentially, reaching another quarterly record. The outlook for our industrial business remains strong. For Q3, we expect to see double digit growth in our broad industrial business, offset somewhat by the build cycle at data centers, which are expected to be flat to down sequentially. Finally, we had a strong quarter in our other business, which represents our non focused markets, including white goods, printers and peripherals. Other was $25,500,000 in the quarter, due in part to a COVID related surge in demand for our products supporting a variety of white goods and printers.
We expect this business to remain around this run rate in the near term. Now for the fiscal Q3 guidance. Reflecting the late timing of the Q2 earnings announcement, we are providing a narrow than typical range, With automotive revenue growth in the high teens sequentially and industrial revenue growth in the mid single digits sequentially, we expect revenue to be in the range of $147,000,000 to $151,000,000 Operating expenses are expected to be up modestly, and we expect non GAAP gross margin to be in the range of 50% to 51%. We expect non GAAP earnings per share to be in the range of 0 point dollars Given the proximity to our recently completed IPO, we will not be taking any questions today. I want to leave you with our confidence in the recovery cycle of our business based on the strength of our bookings, giving us optimism for the future.
Katie?
Thank you, Ravi. This now concludes our call. Thank you for joining us today and your interest in Allegro Microsystems.
Ladies and gentlemen, thank you for your participation on today's conference. This does conclude your program. You may now disconnect.