As the global population with hearing impairments continues to grow, comprehensive diagnosis and treatment equipment for tinnitus and hearing loss has become a core tool in ENT clinical diagnosis and rehabilitation. This equipment integrates pure‑tone audiometry, speech recognition assessment, tinnitus sound therapy, and patient data management. Its measurement accuracy and treatment stability directly determine clinical outcomes. Hospital environments are subject to complex electromagnetic interference: high‑power EMI‑emitting devices such as electrosurgical units and defibrillators, RF radiation from mobile terminals and communication base stations, as well as grid fluctuations and lightning‑induced surges, all of which can cause risks including hearing threshold drift, sound intensity errors, data anomalies, and system crashes.

This solution strictly complies with domestic and international medical EMC standards:

· IEC 60601-1:2005+AMD2:2020 Medical electrical equipment — General requirements for basic safety and essential performance

· IEC 60601-1-2:2014+AMD1:2020 Electromagnetic compatibility (EMC) — Requirements and tests

· YY 0505-2012 Medical electrical equipment — Part 1-2: Electromagnetic compatibility — Requirements and tests (identical to IEC 60601-1-2:2004)

· ISO 13485:2016, ISO 14971:2019 Medical devices — Quality management and risk management

Market-approved medical devices must pass:

· ESD immunity: Contact discharge ±8kV, air discharge ±15kV

· RF field immunity: 10V/m @ 80–2700MHz

· Surge, EFT, conducted disturbance, and other full tests per YY 0505 / IEC 60601-1-2.

With over 16 years of deep experience in EMC protection, Shanghai Leiditech, leveraging its full range of high‑reliability protection components, provides a one‑stop ESD and surge protection solution for tinnitus and hearing loss diagnosis and treatment equipment that meets global medical standards, addressing the requirements for high precision, low noise, and high stability, and building a complete electromagnetic safety defense line from the power entry point to external interfaces.

I. Functional Architecture and Overall Protection Framework of Comprehensive Tinnitus and Hearing Loss Diagnosis and Treatment Equipment

1.1 Core Functions and System Architecture

The comprehensive diagnosis and treatment equipment for tinnitus and hearing loss is a precision medical instrument integrating acoustics, electronics, and computer technology. Its core modules are as follows:

Ÿ Audiometry module: Pure-tone air conduction / bone conduction, speech, and sound‑field audiometry; frequency 125–12000Hz, intensity -10 to 120dB HL, compliant with ISO 8253-1:2010 and ISO 8253-3:2022.

Ÿ Tinnitus diagnosis and treatment module: Frequency/loudness matching, residual inhibition test; acoustic masking, habituation therapy, cognitive behavioral therapy (CBT).

Ÿ Data management module: Patient record creation, report generation and printing; USB/RS485/WiFi connectivity to hospital HIS/LIS systems.

Ÿ Human-machine interface module: High‑definition touchscreen plus physical buttons, conforming to clinical operation habits.

1.2 Overall EMC Protection Block Diagram and Design Principles

The device hardware includes power management, main control, audio codec, signal conditioning, storage, communication interfaces, and human-machine interface units. The power supply and external interfaces are the primary paths for interference intrusion and have the highest protection priority.

The Leiditech EMC team adopts the core design principles of "graded protection, localized discharge, signal integrity first, and medical compliance as the bottom line" to build a three-level protection architecture:

The core advantages of Leiditech's protection solution architecture are:

Ÿ Multi‑stage power entry protection: Surge energy is discharged in stages to avoid secondary interference from single‑stage discharge, while leakage current is strictly controlled to ≤0.5mA, meeting medical equipment safety requirements.

Ÿ Localized interface protection: All protection components are placed as close as possible to the connectors, discharging ESD and surges before they can reach the main board, thereby blocking the interference conduction path.

Ÿ Signal integrity assurance: Low‑capacitance ESD devices (Cj < 1pF) are used on all high‑speed signal interfaces to ensure transmission quality for USB 2.0 (480Mbps), SPI, WiFi, and other high‑speed signals.

Ÿ Full compliance design: The solution has been tested and validated against the YY 0505 / IEC 60601 series standards, enabling direct registration and certification while shortening the customer's R&D cycle.

II. Detailed Explanation of Leiditech's EMC Protection Solution

2.1 DC 5V Power Interface

The power supply connects to an external 5V DC input adapter. Leiditech's EMC team adopts a multi‑stage protection strategy for medical power supplies: a GDT at the front end for high‑current common‑mode discharge, and a TVS (SMBJ6.5CA) at the rear for precise differential‑mode clamping. Meets IEC 61000‑4‑2 Level 4, withstanding ±30kV contact and ±30kV air discharge, as well as IEC 61000‑4‑5 surge Level 4. A Leiditech common‑mode choke (LDW21T‑671M) is also used to suppress common‑mode interference.

2.2 USB 2.0 Interface

The Leiditech EMC team recommends a single-device protection solution to save space and ensure signal integrity. Together with Leiditech's common-mode choke LDW21T-900M, it filters common-mode interference. The SR05 meets IEC 61000-4-2 Level 4 with ±20kV contact and ±20kV air discharge. The SR05W meets Level 4 with ±30kV contact and ±30kV air discharge — 7 times better performance for more stringent electrical disturbances. For overcurrent protection on Vbus, a PTC (SMD1206P075TF) can be added.

2.3 3.5mm Audio Interface (Microphone Input or Speaker Output)

Leiditech recommends the low‑capacitance, two‑channel integrated device LCC05DT3 for ESD protection to save space, or single‑channel ESD devices such as ULC0542C, ESDA05CTL, and ESD5Z5CL in various packages. These meet IEC 61000‑4‑2 Level 4 with ±8kV contact and ±15kV air discharge.

2.4 RS485 Interface

Leiditech recommends the multi‑channel integrated device SM712 for protection. It ensures signal integrity while filtering out noise and passing ESD testing, meeting IEC 61000‑4‑2 Level 4 with ±30kV contact and ±30kV air discharge.

2.5 SD/TF Card Interface

Leiditech recommends the integrated devices USRV05-4 / SR33-04A for protection. With capacitance <1pF, they ensure signal integrity while passing ESD testing, meeting IEC 61000-4-2 Level 4 with ±8kV contact and ±15kV air discharge.

2.6 SPI Interface: High‑speed serial communication interface used to connect memory chips and displays.

2.7 WiFi Antenna Interface

The EMC team recommends the ULC0511CDN30 for ESD protection on WiFi antenna interfaces. Its ultra‑low capacitance ensures signal integrity and meets IEC 61000‑4‑2 Level 4 with ±30kV contact and ±30kV air discharge.

To facilitate BOM management and production procurement, the Leiditech EMC team has summarized all protection components used in this solution as follows:

Conclusion

Comprehensive diagnosis and treatment equipment for tinnitus and hearing loss is a high‑precision medical device directly serving patient health. EMC compliance is not only a mandatory registration requirement under domestic standard YY 0505, but also a core guarantee for international market access and clinical reliability. With over 16 years of accumulated experience in EMC protection technology, a full range of medical‑grade protection components, and a professional technical service team, Shanghai Leiditech provides customers with full‑process support — from solution design and component selection to sample testing and certification guidance.

This solution strictly complies with YY 0505‑2012 and IEC 60601 international medical standards, addressing the three core requirements of electromagnetic immunity, signal integrity, and medical safety. It effectively resolves ESD, surge, and RF interference issues in the complex electromagnetic environment of hospitals, ensuring long‑term stable operation of the equipment and providing reliable technical support for ENT clinical diagnosis and treatment.