Nuvoton's I3810YYI Puts a 3W Class-D Amplifier Inside the Voice Chip

Voice prompts have long been the cheap part of an embedded design — a buzzer, maybe a small speaker, and a playback chip that costs less than the connector next to it. Nuvoton just made them the loud part. On September 22, 2026, the Hsinchu-based chipmaker introduced the I3810YYI, a digital ChipCorder that puts a filter-free Class-D power stage on the same die as the audio decoder: 3 W into a 4 Ω speaker at 5 V, or 1.7 W into 8 Ω. It also handles sample rates up to 48 kHz, mixes three independent playback channels, and addresses up to 2 Gbit of external SPI flash, all inside a 5 × 5 mm QFN-32 rated from 2.7 V to 5.5 V and −40 °C to +105 °C. For appliance, smart-home and industrial designs, the headline is simple: the separate amplifier part number can go away.

A 3W Class-D Amplifier Inside the Voice Chip

The amplifier is filter-free, which matters more than it sounds. A conventional Class-D stage needs an LC low-pass filter on its output — inductors that occupy board area and add cost, as Analog Devices notes in its primer on the topology — plus, in analog-input designs, a DAC and a line driver upstream. Nuvoton routes the whole audio path digitally instead, so the speaker connects to the chip. The company quotes 3 W into 4 Ω and 1.7 W into 8 Ω on a 5 V speaker supply, and pairs the output stage with 8-bit digital volume control plus PGA gain and attenuation settings. Swapping to a different speaker sensitivity or impedance becomes a register write rather than a board revision.

That output level is the practical dividing line. Sub-1 W parts are fine for a confirmation beep in a quiet room; 1.7 W into 8 Ω is audible over the compressor of a refrigerator or the drum of a washing machine. In other words, the I3810YYI is aimed at products where the voice prompt has to be understood, not merely present.

The Numbers Behind It

• Sample rate: two internal master rates, 32 kHz and 48 kHz, each dividing into eight derived rates, topping out at 48 kHz.
• Duration: 1092 minutes (18.2 hours) using 8 kHz/4-bit ADPCM, or 46 minutes using 48 kHz/16-bit PCM.
• Storage: 28-bit flash addressing for up to 2 Gbit of external NOR flash, with a pass-down command for direct access to the external device.
• Compression: µ-Law, differential µ-Law, PCM, enhanced ADPCM, and variable-bit-rate optimized compression.
• Channels: three independent playback channels, each with its own memory management and decompression resources; any or all can be mixed, controlled separately, and run at different sample rates.
• Interfaces: SPI, I²C, or GPIO trigger modes, with one SPI or I²C port and eight multiplexed GPIOs. Audio can come from external SPI flash, an I²S input, or digital audio pushed straight from an MCU over SPI; playback and streaming paths include flash-to-PWM, I²C-to-PWM, I²S-to-PWM and others.
• Electrical and package: 2.7 V to 5.5 V, −40 °C to +105 °C, QFN-32 measuring 5 × 5 mm². Nuvoton lists home appliances, smart-home devices, industrial and safety systems, consumer electronics and commercial equipment as target applications.

Where It Sits in the ChipCorder Family

The ChipCorder name is older than Nuvoton itself, part of the ISD audio line that came across when Nuvoton was spun off from Winbond Electronics. The family splits in two: the Digital series leans on DSP-based compression, large external memory, high sample rates and an I²S interface for automotive, medical and industrial work; the MLS series trades sample quality for multi-level storage, ultra-low power and very long playback on battery. Nuvoton's own line about the Digital series is that it needs nothing external except a speaker. The I3810YYI takes that claim one step further by absorbing the amplifier too. Against the parts already on the shelf (pricing from Nuvoton's own eStore, the 2,000-piece tier):

• I2130YYI: QFN-20 (4 × 4 mm), 2.7–3.6 V, −40 to +85 °C, 1 Mbit embedded flash, 30 seconds, Class-D at 400 mW @ 3 V; about USD 0.91.
• I2360YYI: QFN-32, 2.4–5.5 V, −40 to +85 °C, 2 Mbit embedded flash, 64 seconds, three-channel mixing, Class-D at 1 W @ 5 V; about USD 1.14.
• I3800FYI: LQFP-48 (7 × 7 mm), 2.7–5.5 V, −40 to +85 °C, external flash for roughly 64 minutes, 80 dB SNR, Class-D at 1 W @ 5 V; about USD 1.06.
• I3810YYI (new): QFN-32 (5 × 5 mm), 2.7–5.5 V, −40 to +105 °C, external flash up to 2 Gbit, three-channel mixing, Class-D at 3 W @ 5 V into 4 Ω.

So the previous ceiling in this family was 1 W at 5 V, and every part topped out at +85 °C. Both the 3 W output and the +105 °C rating are firsts for the line — and 105 °C is not a marketing number for smoke detectors, fire panels or motor-drive cabinets, where the ambient temperature alone can sit near 85 °C.

Why Voice-Prompt Boards Are Consolidating

The traditional bill of materials for a voice-prompt board reads: voice chip, plus amplifier, plus the parts nobody counts until layout — coupling capacitors, extra routing, and whatever the EMI scan demands. Analog Devices makes the arithmetic blunt in its design notes: a digital-input, filterless Class-D amplifier removes the DAC and line driver that analog-input types require, cuts the number of external capacitors and routed nets, and in one documented single-channel example needs a single bypass capacitor for a total solution area of 3.69 mm². Texas Instruments reaches the same conclusion from the protection side, noting that integrated short-circuit protection and an integrated LDO save PCB area and BOM cost precisely because they are not separate components.

The trend is already visible closer to home. WayTronic, a Chinese voice-IC vendor, describes the typical blood-pressure monitor board as "MCU + LCD driver + amplifier chip + voice chip," a stack it calls space-hungry and expensive; its WT2003H answers that by merging a 32 × 4 LCD driver, an amplifier and voice playback into one part, offered in a QFN32 as small as 4 × 4 mm. WayTronic's English material states plainly that the WT2003H series "integrates a 0.5 W Class-D amplifier and supports direct driving of 8 Ω speakers." So the novelty in the I3810YYI is not the idea of an integrated amplifier — it is the power class. Nuvoton has moved the single-chip ceiling from 0.5–1 W up to 3 W.

Market forecasts support the direction without agreeing on the number. China's BGAO report, citing its 2025–2030 smart voice market study, puts the global intelligent voice control chip market at USD 7.04 billion in 2024, growing at a 9.06% CAGR to USD 14 billion by 2032, with automotive the fastest-growing segment at a 10.02% CAGR. Business Research Insights, in a report updated in August 2026, estimates roughly USD 8.9 billion in 2026 rising to USD 19.4 billion by 2035, a 9.2% CAGR. The two disagree on scale, but they agree on the mechanism: as voice prompts move from "it beeps" to "it is understood," output power and integration both stop being optional.

HSY Perspective

We have been selling Nuvoton's ChipCorder parts for years, and the questions we get have shifted. It used to be "how many seconds can it hold" and "does it come in the package I already use." Lately, half the inquiries open with "can this drive my 4 Ω speaker directly," followed immediately by "I really don't want another amplifier." The reasoning behind that is not complicated. Boards keep shrinking, the voice prompt is usually bolted on late in the project, and a design team would rather pay a few extra cents for the voice chip than find room for an amplifier and a handful of passives on a board that is already full — and then re-run EMI. So a 3 W amplifier inside the voice chip saves a part number, an EMC cycle and a board spin, not just a line on the BOM.

One caution we pass along every time: 3 W is a datasheet condition of 5 V into 4 Ω, and real hardware discounts it. Speaker impedance, enclosure leakage and sensitivity all eat into the number, and we have watched customers chase "not loud enough" back to a leaking housing rather than the silicon. The part runs from 2.7 V to 5.5 V, but if you want the full 3 W, the audio rail has to be designed at 5 V. A 3.3 V system driving a large speaker is choosing between a boost converter and a lower-output alternative.

As for what we keep on the shelf: for small, cost-sensitive announcement tasks we are usually quoting the I2130YYI; for three-channel mixing or 48 kHz, it is the I2360YYI or I3800FYI. Nuvoton has not published a mass-production schedule or unit pricing for the I3810YYI yet — the product page's Resources tab still returns "Data not found," so the datasheet is pending. What you can get today is the NT-I3810 evaluation board, listed at USD 22 on Nuvoton's own eStore, paired with the NU-ISDMINUSB dongle and ISD-VPE software. Nuvoton is one of the few logic IC vendors in Taiwan that still runs its own 6-inch wafer fab, so long-term supply on an analog-heavy voice part is not our main worry; schedule and pricing in the coming quarters are.

If your current design is a voice chip plus a discrete amplifier, it is worth an afternoon to put the I3810YYI into the comparison table and rerun the numbers against your own speaker and rails. If all you need is a short confirmation tone, skip it — the cheaper parts deeper in the family will do the job.

Sources: Nuvoton press release, "Nuvoton Introduces I3810YYI Digital ChipCorder with Integrated 3W Class-D Amplifier for High-Performance Audio Playback" (nuvoton.com, September 22, 2026); Nuvoton I3810YYI, I2130YYI, I2360YYI and I3800FYI product pages and the ISD ChipCorder family pages (nuvoton.com); TECHDesign step pricing and the NT-I3810 evaluation board listing (techdesign.com); 21ic (21ic.com, September 22, 2026); Analog Devices, "How to Easily Achieve Superior Audio Performance with Plug and Play Digital Input Class D Amplifiers" and "Class D Audio Amplifiers: What, Why and How" (analog.com); Texas Instruments, "How to Choose a Class-D Audio Amplifier," SLOA290 (ti.com); WayTronic WT2003H technical notes and English site (wt588d.com, wtsoundic.com); China BGAO, "2025 Smart Voice Market Insight" (chinabgao.com, June 10, 2025); Business Research Insights, "Intelligent Voice Control Chip Market 2026–2035" (updated August 17, 2026).