Good afternoon, and welcome to our conference call to discuss Cohu's fourth quarter 2021 results and first quarter 2022 outlook. I'm joined today by our President and CEO, Luis Müller. If you need a copy of our earnings release, you may access it from our website at cohu.com or by contacting Cohu Investor Relations. There's also a slide presentation in conjunction with today's call that may be accessed on Cohu's website in the investor relations section. Replays of this call will be available via the same page after the call concludes. Now to the Safe Harbor. During today's call, we will make forward-looking statements reflecting management's current expectations concerning Cohu's future business. These statements are based on current information that we have assessed, but which by its nature is subject to rapid and even abrupt changes.
We encourage you to review the forward-looking statement section of the slide presentation and the earnings release, as well as Cohu's filings with the SEC, including the most recently filed Form 10-K and Form 10-Q. Our comments speak only as of today, February 10, 2022, and Cohu assumes no obligation to update these statements for developments occurring after this call. Finally, during this call, we will discuss certain non-GAAP financial measures. Please refer to our earnings release and slide presentation for reconciliations to the most comparable GAAP measures. Now I'd like to turn the call over to Luis Müller, Cohu's President and CEO. Luis?
Good afternoon, everyone, and thanks for joining us. Fourth quarter revenue was approximately $192 million, and non-GAAP EPS was $0.72, both higher than the midpoint of our guidance. Full year 2021 revenue of $887 million grew 39% year-over-year, capping a five-year revenue CAGR of 26%, one of the strongest in our industry. Full year non-GAAP EPS of $3.20 was up 169% year-over-year, demonstrating the scalability of our business model. We also had several design wins that expanded our products into new customers, achieved year-over-year revenue growth of 130% in inspection and metrology, and 25% in interface products business, and supported a significant ramp in the automotive and industrial segments. Coming back to Q4, we had a multitude of customer design wins this past quarter.
Our tester business received volume orders for the Diamondx platform from a Japanese automotive semiconductor customer; qualified and secured initial volume order and shipment of Diamondx tester to a Korean-based display driver customer, delivering on the goal to expand our presence in this device segment; capture an important RF front-end module design win from a leading Japanese semiconductor manufacturer that is adopting Cohu's PAx tester with the RedDragon RF instrumentation suite; and got an initial PAx system order from a U.S.-based RF semiconductor manufacturer for testing Wi-Fi 6E and Wi-Fi 7 devices, displacing this customer's internal rack-and-stack solution. In the interface business, we're gaining traction with a new line of power and precision analog contactors used in testing semiconductors for automotive and industrial applications.
The handler business followed with capturing RF sales at a Taiwanese customer, being selected by a leading German customer, and receiving first order for testing automotive ADAS processors on our MATRiX handler equipped with T-Core active thermal control. Receiving the first order for our Eclipse with T-Core active thermal control for testing Tier 1 mobile processors at a leading Korean OSAT customer. A few other design wins in the growing automotive and industrial semiconductor markets in China. Our DI-Core data analytics capped the quarter with another win at a customer in Europe. In all, this was one of the longest lists of single quarter design wins that I can remember in my tenure at Cohu and gives me confidence that we are on path to meet our midterm revenue target.
We enter 2022 with an 87% estimated test sale utilization, strong backlog, and increasing demand for our products. We remain cautious about the tight supply chain environment and potential impact of Omicron in the next few months. We're also excited by the customer traction and the opportunity to broaden our Semi test applications with our Diamondx tester, growing interest in our Neon inspection and metrology technology, expansion in test interface products, and many ongoing qualifications of our DI-Core data analytics software solution. As a result, we recently increased Cohu's midterm financial targets to revenue of $1 billion in non-GAAP EPS of $4 per share. Additionally, many of our customers have publicly announced the recent quarterly results and provided growth forecasts for 2022, which emboldens our view that this will be another good year for Cohu.
We don't typically have a single large customer that drives revenue in a year, but count on aligning our product strategy to segments of the market and customers that have outsized growth prospects. We forecast 2022 to be a strong year for our semiconductor tester group, which is starting to benefit from the many recent customer design wins and expansion within and beyond the RF mobility segment, continued gains in inspection and metrology, working to qualify a Neon at several new customers in 2022, and deploying new vision solutions later in the year that further align our products to tighter quality requirements in advanced packaging. We're also planning another growth year for the interface business, particularly in automotive and industrial power applications and high-performance RF mobility.
DI-Core business is lifting off at many automotive and industrial semiconductor manufacturers, augmenting our product portfolio and delivering value via mining sensor data in our products to improve our customers' productivity. Finally, we forecast handler demand to moderate in 2022, which we expect will drive sequential consolidated gross margin expansion this year. Order forecasts remain strong, and the challenge continues to be to secure enough from the supply chain to satisfy demand. As always, we will continue to assess opportunities and make investments based on high ROI and strong future cash flow potential. Let me now turn it over to Jeff to share fourth quarter results and provide specifics about our Q1 guidance. Jeff?
Thanks, Luis. Before I walk through the Q4 results and Q1 guidance, please note that my comments that follow all refer to non-GAAP figures. Information about the non-GAAP financial measures, including the GAAP to non-GAAP reconciliations and other disclosures, are included in the accompanying earnings release and investor presentation, which are located on the Investor page of our website. Now turning to the financial results. Cohu delivered strong revenue and profitability in the quarter. Q4 revenue was $191.9 million and at the higher end of our guidance range. Total revenue for full year 2021 was $887 million, growing 39% over 2020 and setting a new Cohu record. During the fourth quarter, two automotive segment customers each accounted for more than 10% of sales. For full year 2021, one automotive segment customer accounted for approximately 14% of sales.
In the fourth quarter, Cohu's gross margin was 44.1% and in line with our guidance. Full year 2021 gross margin was 43.6%. Operating expenses for Q4 were $50.7 million, also in line with guidance. Full year 2021 operating expenses were approximately 23% of revenue and lower than our midterm target by about 300 basis points, supplementing profitability as we expand gross margin. Fourth quarter non-GAAP operating income was 17.7% of revenue, and adjusted EBITDA was 20%. Full year operating income was 20.5%, and adjusted EBITDA for 2021 was 22.2%. Return on invested capital in the fourth quarter was approximately 48%, and full year ROIC was approximately 55%. Cohu generated a net tax benefit in Q4 due to the recognition of foreign tax credits applied to U.S. federal taxes.
The non-GAAP effective tax rate for full year 2021 was approximately 10%, benefiting mainly from U.S. NOLs, R&D credits, and the foreign tax credits recognized in Q4. Non-GAAP EPS for the fourth quarter was $0.72. The foreign tax credits recognized in Q4 contributed $0.15 to EPS. The full year 2021 EPS was $3.20, growing 169% year-over-year. Record revenue growth and profitability in fiscal year 2021, coupled with strong customer demand, backlog of $293 million at the end of Q4, and increasing traction in key growth markets, led to a recent expansion of our mid-term financial targets to revenue of $1 billion and non-GAAP EPS of $4.
Moving to the balance sheet, the cash grew to $380 million, and total debt was relatively unchanged quarter-over-quarter at $119 million. However, we did make a voluntary debt repayment in early Q1 of $7 million to reduce the Term Loan B outstanding balance to approximately $95 million. The Q4 cash balance is net of $7.3 million used to repurchase approximately 207,000 shares of common stock during the fourth quarter. Cash flow from operations remains strong, and capital additions, mainly to support expansion of our contactor manufacturing operations, remains modest overall. Cohu's balance sheet is in a strong position to support debt reduction, the share repurchase program, and investment opportunities to expand our served markets and technology portfolio in line with our growth strategy. Now moving to our Q1 outlook.
We're guiding Q1 revenue to be between $188 million and $202 million. As I mentioned, customer demand remains strong, and the midpoint of our Q1 revenue guidance reflects a small increase over Q4 revenue. Supply chain remains challenging for both Cohu and our customers, resulting in small but dynamic shifts in revenue as some shipments were pulled into Q4 while others have been pushed beyond Q1 due to material shortages of wafers and lead frames among our customers, and supply constraints on certain semiconductors used in our testers.
Order backlog, customer demand, and test cell utilization remains strong and bodes well for sequential revenue growth in Q2. However, given the uncertainty with supply chain and semiconductor availability, we're hesitant to comment in further detail about future quarterly revenue at this time. Q1 gross margin is forecasted to be approximately 44.5%. We're seeing a moderation of automotive test handlers and quarter-over-quarter growth in tester revenue, improving product mix and having a positive impact on gross margin. Q1 operating expenses are projected to be approximately $53 million, and we're projecting Q1 interest expense to be approximately $1 million. Q1 debt repayment will be approximately $7 million, reflecting the payment already made at the end of January. We expect Q1 adjusted EBITDA at the midpoint of guidance to be approximately 19%.
The Q1 forecast non-GAAP tax rate is approximately 16% at the midpoint of guidance. Full year 2022 non-GAAP tax rate is estimated to be approximately 18%. The diluted share count for Q1 is expected to be approximately 49.5 million shares. That concludes our prepared remarks. Now we'll open the call to your questions.
As a reminder, if you'd like to ask a question at this time, please press the star, then the number one key on your touch-tone telephone. Our first question comes from Toshiya Hari with Goldman Sachs.
Hi, good afternoon. Congrats on the strong results, and thank you for taking my question. Luis, I was hoping you could talk a little bit about the supply environment. It looks like you're embedding some sort of impact from a supply perspective in your Q1 outlook, both directly impacting you guys, but also impacting your customers. What are some of the primary causes, and when do you expect some of these challenges to abate? I've got a quick follow-up.
Hi, Toshiya. Yes, you're correct. We are modeling a continued challenge at our customers, both from a sourcing wafers as well as sourcing substrates and lead frames perspective. So it's hard to quantify, but we have some understanding in a few instances from our customers of the situation. Then on our own side, as we had been mentioning now for several quarters, the supply chain remains pretty tight. At this stage, even you know, shifting a little bit to tightness in sourcing some discrete electronic components for motors, controllers, as well as sourcing semiconductor devices themselves.
Maybe, Toshiya, I can add to that. For Q1, the semi shortage we're modeling or we've adjusted the forecast by $8 million-$10 million as a result of both semi shortage through our supply chain, as well as some customer delays, as Luis explained.
Got it. That's very helpful. I guess as my follow-up. How are you guys thinking about 2022, the full year, in terms of your different products? I think Luis, in your prepared remarks, you talked about, you know, strong design wins and semiconductor tests. I think you had positive comments on your contactor interface business, and you also talked about moderation in handlers. Curious how you're thinking about those three large buckets within your business for Cohu specifically, but also how are you thinking about the SAM growth relative to 2021? Thank you.
Sure. Why, why don't we start at the end here with the SAM portion and then work our way back to the company then. We're looking at the overall TAM for tests to be largely the same year-over-year, 2021-2022. From a SAM perspective, we've been saying this for a little while now, that we have about a $1.4 billion SAM on the tester market. Frankly, that is not changing. What's changing is our ability to penetrate into that SAM. We're fairly emboldened by design wins that we scored, particularly in the second half of last year and what is still at play here going into 2022. To a degree, very happy to see traction that we're getting in the DDIC market, display driver IC test market with our tester business.
Also power management and mixed signal, particularly in the automotive side. We continue to get some opportunities too, in displacing in-house rack-and-stack solutions in the RF-FEM as well. It doesn't really change the SAM, it more so changes our penetration into the SAM. That's the positive side. On the contactor business, a little bit more difficult to forecast what the market is gonna look like in 2022. We think it'd be, you know, somewhat flat to up 7% on the contactor side. But we are continuing to gain new customers and new penetrations, particularly for power management devices and precision analog semiconductor test. On the handler side, we think combination of things.
One, the market itself will probably moderate down in conjunction with the automotive moderation that we've been talking about, and that should have, you know, a similar effect on our business in our test handler automation business. Since we have such a large share in the automotive test equipment. I hope that answers your question for sure.
Yeah. That's great. Thank you for all the details.
Our next question comes from Brian Chin with Stifel.
Hi there. Good afternoon. Congratulations on the strong 4Q, and thanks for letting us ask some questions. Luis, first to follow up on that last question, relative to the test handler business, do you care to put any sort of brackets around magnitude, sort of duration in terms of you know, the moderation you see in the business? Clearly, you still would've been up in terms of growth or not constrained in Q1, even more than you're guiding right now. It looks like you do have some offsets vis-a-vis you know, the many order commentary and wins that you talked about earlier in the call. Just wondering if you could put any more brackets around sort of that moderation in the handler business.
Sure. Yeah. No, I think I can. The way we look at the handler business is that in 2021 last year, we had a combination of growth and also a rebound from the constrained environment, particularly in automotive in 2020. As we look to 2022, I think there's gonna be a plus and a minus here, the plus being electrification of drivetrain in the automotive space continues to be very strong and progressing very well. I mean, you can't today go out and buy vehicles because of lack of semiconductors, as you all know. At the same time, I think that rebound that happened predominantly in the first half of 2021, we sized that netting of expected growth in 2022 to be about a $40 million-$50 million sort of net negative, if you will, where you know, the so-called moderation that we're commenting here for the handler business going into 2022.
Got it. Okay. That's helpful. I, you know, a question about the test contactors. I'm curious to what extent. I know, number one, you have some gross margin improvement initiatives that are expected to be pretty meaningful towards the, you know, the end of the second half of the year. Wondering if those are still on track. Two, from that standpoint as well as from a revenue shipment standpoint, I know there's been a lot of disruptions, discontinuities out in Southeast Asia where you have some manufacturing. Have you been impacted at all by that, as well?
Hey, Brian. So with respect to the gross margin on contactors, we ended Q4 as we suspected in a strong position, just a little bit above 40%. Yes, still anticipating significant increase there throughout the year. Second half, still anticipating mid-40% gross margin for the contactor business. Certainly with, you know, the workforce in Asia, Philippines primarily, it's been a challenge, so we're working through it. We haven't had any, you know, significant downtime as a result, but it just continues to be a challenge.
Okay. Yeah. Fair enough. I know you didn't wanna make too much forward revenue commentary, but I will ask a question about seasonality. I know that, you know, taking on board some of the, you know, year- to- year effects you're talking about in terms of the various end products, you know, usually 2 Q and 3 Q tend to be sort of stronger seasonal periods. Do you think the demand still speaks to that kind of rate? You know, the supply may speak to something different. And again, there's other overlays in terms of your business, but any way to think about sort of that seasonality in your business?
Yeah, you can add a little bit. Yeah, Brian, still seeing strong demand. Still, you know, we had a book-to-bill over one in Q4, and it's looking pretty strong in Q1 so far. The demand is still there. The real wild card is the supply chain.
Yeah. I think that covers it.
Yeah. Okay. Thanks, guys.
Our next question comes from Krish Sankar with Cowen and Company.
Yeah. Hi, thanks for taking my question. I had two of them. Luis or Jeff, thanks for the color on the SAM opportunity in FY 2022. If I kind of roll it all together between the tester, handler, and the contactor, it seems like your FY 2022 revenues could be maybe flat to up low single digits. Is that a decent proxy? Or any thoughts on that?
Yeah, Krish. When you put it all together, the reality is, I think the market is about the same in 2022 as 2021, you know, putting it all together. What we do have is, we have a moderation in the handler side that I already spoke to the tune of $40 million-$50 million of sort of that automotive bubble that we saw in 2021. Then we do have sort of the tailwind of customer gains that we have had here with the tester business in DDIC, PMIC, mixed signal, and even RF-FEM, as well as growth from customer gains as well in the contactor business that we expect to continue into 2022. So you put that all in the blender, right? The reality is, you know, the SAM is about the same. It's more of a story of gaining market share in 2022.
Yeah. That's true. I think one more thing to remember, Krish, is that, you know, we sold PCB Test halfway through last year. They contributed $26 million to our $887 million for last year. You know, that's a gap that we're looking to make up.
Got it. Super helpful. Thanks for that color. Just to follow along the same path, you know, given that the mix shift is more towards tester from handlers, you know, that's a tailwind for gross margins, and then obviously you're gonna be reducing or improving your gross margin for the contactors. You know, it just optically makes sense that, you know, the gross margin should grow this year compared to last year. How should we think about OpEx given all the rising costs? I'm trying to figure out the implications for earnings.
For OpEx, Krish, is that what you had mentioned?
Yeah.
Is that your question?
A, number one, gross margin going up, does it make sense? B, how to think about OpEx?
Okay. We guided Q1 OpEx at about $53 million. I think we will have a tight range of OpEx for 2022, anywhere from probably $52 million a quarter to $54 million a quarter. Just sort of depending on not only revenue and some of the variable costs we have, commissions, travel, things of that nature. You know, on a quarterly basis, we have some items that don't necessarily, you know, more, let's call them seasonal, if you will. That range is a range that we're modeling for the year, $52 million-$54 million.
From a cost increase, we have, much like last year, we have been passing that through to customers. You know, there may be some delays like we had last year when we passed it through, but eventually we do catch up to those cost increases.
Perfect. Thank you very much. Really appreciate it. Thanks, Luis. Thanks, Jeff.
Our next question comes from Craig Ellis with B. Riley Securities.
Yeah. Thanks for taking the questions. I wanted to start just by clarifying a point. I think, Jeff, you indicated that the supply chain issues that you were seeing in the near- term were worth about $8 million-$10 million. As we look at the 1.6% guide, and I think three months ago, we were thinking that the business might grow 5%-10%, is the difference between the 1.6% and the 5%-10%, that $8 million-$10 million, or have there been some moving dynamics in terms of how you're looking at 1Q from where you were three months ago?
Craig, we had a little more rollback into Q4. You know, the revenue there was a little bit higher than our midpoint of guidance. Yeah, that you're correct. I had said $8 million-$10 million as a Q1 impact related to supply chain.
Got it. Okay. Then secondly, nice to see the $293 million in backlog. Can you just comment on what you're seeing in terms of how that's distributed across the different products? And as you look at the backlog, how far out is that extending? Is that giving you visibility into the second half of the year, or is that really just through the second quarter? Any color on breadth and duration would be helpful.
The duration is really up to two quarters. There's some that goes beyond that, but it's not meaningful. It's color on up to two quarters. In terms of the breakdown of the backlog, you know, I think it's close to where we were on an annual basis from a revenue perspective. Now, over the last quarter or two, certainly testers have gotten stronger as automotive test handlers have moderated. You know, I would say from a total makeup, it's probably 55%-60% handlers, and then close to 30% testers, and the balance would be contactors.
Got it. Lastly for me, nice to see the company being active on the buyback program with the 7 million, given where valuation is versus 10-year levels. Can you just help us understand how you're thinking about utilizing that buyback program as you look ahead at the first quarter there?
Yeah, I think the target in the first quarter is gonna be really to offset dilution. I think it's gonna be similar to what we did in Q4, Craig. I would model, you know, somewhere close to 200,000 shares, something close to what our Q1 results were.
Got it. Thanks very much, guys. Hop back in the queue.
Thanks, Craig.
Our next question comes from Quinn Bolton with Needham.
Hey, guys. Just wanted to sort of ask a question about 2022. You know, I know you're not commenting beyond the second quarter, and you talked about seeing sequential growth continuing to Q2. You know, kind of walking through the puts and takes for the year, it sounds like revenue for the business ex-PCB Test is gonna be roughly flattish in the $850 million-$860 million range. You know, I look at the first quarter guidance at $195 million. It sort of feels like, you know, either you have a really big June quarter or perhaps you're seeing some of the revenue that, you know, shifting out of Q1 into either Q2, Q3, maybe even into Q4.
I guess, you know, to get to sort of a flat year, it seems to imply perhaps a stronger second half than you might normally see. I'm just wondering if you guys agree with that, or do you just see a sort of whatever pushes out of March might be captured in June?
Well, yeah, in terms of trying to recapture what pushes out of March into a particular quarter, that's hard to do based on the uncertainty. You know, again, we're seeing a lot of strength in the business right now, a lot of good indicators. You know, the projections for the market are, as Luis went through, similar to what they were last year. It's just, this is one of the reasons we're not giving any kind of indication of Q2 revenue is just. There's just too much uncertainty. Whether that pushes to Q2, Q3, what comes out of Q2, Q3, it's just too uncertain at the moment.
[audio distortion] visibility.
Yeah. Right. You know, we're really hesitant to, you know, as you can tell, to put any kind of parameters around this.
Yeah, realistically, Quinn, we're not in a position to talk about second half of the year yet. It's just too soon to have a good educated guess of what's gonna happen that far out.
Is it fair to say, though, that you're sort of more confident in your outlook that the ex-PCB Test, the revenue will be roughly flattish, what's harder to call is just the timing of the revenue? Or do you think that there's risk to that $850 million-$860 million kind of flattish year-on-year outlook?
Quinn, I think we're saying we're confident in what we have been talking about for the last one to two quarters, which is we would see a moderation on the handler business due to the automotive snapback effect we talked about. We would see an increase on the tester business going into the first half of this year. If I would say perhaps we're a little, you know, positively surprised by the strength of some of these design wins that we got recently in the sense of they're translating into volume orders already. That's exciting. We were confident on the improvements on the contactor business, both the revenue growth and the improvement in gross margin. Those are all playing out as we expected. I'm a little, say, disappointed on the continued tightness on the supply chain side.
You know, I would've thought it would've start easing a little bit, and it's not. That's remaining. That creates a little bit more of aggravation here in the near- term than we expected. So far everything is playing out the way we expected, except for, you know, supply chain remains a challenge. I don't know for the second half of the year, it's too early to comment. I don't know how to answer your question for the full year at this point.
Understood. Okay, guys. Thank you very much.
Our next question comes from Tom Diffely with D.A. Davidson.
Yes, good afternoon. Thank you. Very nice to hear about the mini design wins. Wanted to dig in just a little bit more on the RF test side in Japan. Luis, how big is that market, and is it currently being served with in-house solutions, or are there specific competitors there?
The Japan customer win, I mean they are one of the leaders in the RF-FEM space. I think as we mentioned a few quarters ago, we had a couple more large RF customers to win, or perhaps more than a couple, but a few more RF customers to win. This is a very important penetration win for us. We've been working on it for over a year, and we finally got a beachhead entrance. That is a very important penetration there. We also had some design wins at a U.S.-based RF-FEM customer, where we're displacing in-house rack-and-stack solution for a Wi-Fi 6E and Wi-Fi 7 application. Yeah, I think that's it for the moment on the RF.
Okay. Thank you. Jeff, moving to the target model. I'm curious, you know, as we bridge the gap from last year's results to the target model, on the margin expansion side, is that a combination of just product mix and scale, or are there any other programs that you need to implement to get to the higher margin?
No. Those would be the two key items. Mix in terms of growth in testers and contactors, moderation in the handlers. Then the scale is really more about the contactors and the internal manufacturing there. Yes, increasing the revenue and the product that flows through the Asia-based or Philippines-based, Japan-based factories.
Okay. That's helpful. Just quickly focusing on the cash generation. You know, the roughly 10% free cash flow yield last year, you know, very nice, but you're projecting 18% free cash flow on the target model. It seems like there's a bigger jump in free cash flow than there is for, you know, EPS or margin. I'm just curious, what is the incremental driver there on a kind of a bridge-the-gap basis?
Yeah. This year we saw, you know, a significant increase on the balance sheet and receivables and inventory. I think we're gonna get a better churn and be able to improve the DSOs and the inventory days there. That's the target, and those are the actions in front of us.
Great. Well, thank you both.
Yep. Thank you.
Our next question comes from Atif Malik with Citi.
Hi, thanks for taking my question. Luis, if I remember it correctly, last year you guys were a little bit early in talking about test utilization coming down on the mobile side, and it seems to me like that has stabilized and started to improve. Curious on the moderation in the auto handlers, is this something that you're starting to hear from your customers, or you just expect kind of cyclicality to play out? Are there any signs right now, or are you just you know, being conservative?
No, I don't think it's any speculation. We have seen obviously a pretty tremendous ramp in the automotive demand for our test handlers in the first half of last year, 2021. The moderation has started already on the third quarter of last year, and then back to the normal seasonality pattern that we expected here in the fourth quarter and the first quarter. There's still a lot of unfulfilled demand in the automotive market. I just think that snapback effect that we saw in the first half of last year ain't gonna repeat itself. The forecast, the order forecast, the backlog we have on hand pretty much supports that view already.
Great. If you can touch on, you know, Wi-Fi 6E. I understand that test demand is improving this year. Within that test demand, if you can rank order, RF versus display driver versus power management. If you can just rank order, which end market is the strongest?
Well, it in part has to do with our penetration. Our share penetration in each one of these segments. The RF segment will continue to be the strongest for our tester business in 2022, but that's simply due to the fact that that's the area we have our strongest share at the moment and continue to gain some new customers as I described here in the prepared remarks, one in Japan, one in the U.S. in the RF-FEM. Nevertheless, if I were to look at just pure growth year-on-year or as a percentage of revenue growth year-on-year, we are really bullish on the DDIC market, the display driver market. We had a very, very important qualification win in Korea in the fourth quarter.
That's gonna translate into volume business, probably starting this quarter and into the subsequent quarters this year. We have had some new devices qualified on the platform at existing customer in Taiwan. Although fabless customers in reliability testing at OSATs. Really emboldened by the traction in the DDIC and frankly even a bit surprised by how fast that traction is translating into volume business. Also very happy to see the PMIC and mixed signal win in Japan. I think there's a lot more that we can and need to do in the PMIC and mixed signal side. I'll expect that will be you know, more of a story that we'll be discussing perhaps towards the second half of the year.
Great. Thank you.
Our next question comes from David Duley with Steelhead.
Thanks for taking my question. I apologize I missed part of your prepared remarks. I'm just curious what you kind of think for the size or the growth rate of the test market this year. You know, Teradyne kind of mentioned it was flat, but they have a big headwind with their largest customer. I imagine, they mentioned that there's pretty decent growth outside of the mobility and Apple business. I'm kind of wondering what your guess is for what the growth rate of the test business, market of the test business might be this year.
You know, David, given our size in that market, we tend to focus more on our SAM and the growth opportunities in our SAM. I mean, I looked at both Teradyne and ADVANTEST, sort of bellwether what they're saying for the market size. Obviously, as you pointed out, Teradyne claim it should be flat. ADVANTEST claims, I don't know, I think a 10%-12% growth year-on-year, talking about the SoC market in particular. We, as I mentioned in the prior question here, we're seeing really interesting opportunities in DDIC and PMIC and mixed signal. You know, is it because those markets are growing like ADVANTEST says? Or realistically for us, they are also design wins, recent design wins. We see growth opportunity for our tester business. We think our tester business is gonna nicely grow in 2022.
As far as the market grows, you know, I guess I'll take the bellwether comments and say it's somewhere between 0% and 12% growth based on Teradyne and ADVANTEST.
Okay. Excuse me. Did you mention, I think, at one point or another, that you expected to gain share in 2022? Could you just elaborate in what parts of your business you expect to gain share?
Sure. It is, you know, predominantly on the tester and the contactor side. We have once again done a really good design win in the DDIC market in Korea in Q4. We're seriously expanding our presence now in Taiwan. DDIC is a tremendous opportunity for us. We're also expanding our presence in the mixed signal and power management IC space with our tester and some new instrumentation that were brought in and some refresh that we've done in 2021. There is a little bit more to do in the RF-FEM, including these wins in Japan and in the U.S. RF-FEM customers. That's not the end of the road, by the way. I mean, we just broke in.
I think we've got to capture the revenues too and design all the different applications. The contactor side, we had some new products in power management and precision analog that are getting very good orders, very good order rate here in the fourth quarter and starting at the first quarter this year. We grew the contactor business 25% in 2021 year-over-year. We do expect to grow it again in 2022. Then lastly, the inspection and metrology. You know, we had a tremendous year in 2021. We grew 130% year-over-year in revenue. A lot of it has to do with this so-called Neon platform with infrared imaging capability. Just a really good attachment to mobile device applications.
We have a list of customers that we're targeting to win in 2022, and then later in the year, we do expect to bring in some new vision technology that continues to expand our penetration thereafter more into high-performance digital and particularly where there is vertical stack, semiconductor stacking or 3D packaging into 2023. Those are the primary areas of growth for the business in 2022.
I'm sorry if you already addressed this, but Jeff, it seemed like the earnings per share in the December quarter were a bit above where street expectations were. Could you just outline what the key reasons for that were?
Yeah. The key reasons a little more revenue, slightly better gross margin. We had foreign currency gain of about $700,000. Those are some small differences. Depending on a tax provision, we realized a foreign tax credit in the quarter, which drove a $2 million tax benefit, you know, as a credit as opposed to a debit in the quarter. That added $0.15 to EPS.
Gotcha. Thank you.
Mm-hmm.
That concludes today's question and answer session. I'd like to turn the call back to Jeff Jones for some closing remarks.
All right. Thank you, everybody. Appreciate you joining the call, and we'll talk to you soon. Thank you.
This concludes today's conference call. Thank you for participating. You may now disconnect.