The HIS20SMD-S operates as a pulsable thermal infrared emitter. A micro-fabricated heating element — built from a high-melting-point metal and coated with a patented nanostructured high-emissivity surface — is resistively heated to approximately 700 °C when electrical current is applied. At this temperature, it radiates infrared energy approximating a near black-body spectrum, transmitted through the integrated Si-ARC optical window.

Silicon (Si) with anti-reflection (ARC) coating is selected for its excellent infrared transmission from approximately 2.5 µm to 14 µm — a range that encompasses both the near-infrared molecular fingerprint region and the longer-wave mid-infrared atmospheric window. This broader spectral coverage makes the HIS20SMD-S particularly valuable for multi-gas detection systems and applications requiring sensitivity to heavier molecules and complex organics that are not detectable with narrower-window emitters.

The Si-ARC window also provides physical protection to the radiating element while offering higher infrared transmittance across the mid-IR range compared to alternative window materials. The anti-reflection coating minimises Fresnel reflection losses at the silicon surface, maximising optical output power delivered to the detector.

Support for modulated output at up to 14 Hz (50% modulation depth, square wave, 50% duty cycle) enables lock-in detection techniques that dramatically improve signal-to-noise ratio — critical for high-sensitivity environmental monitoring instruments, trace gas analysers, and industrial safety systems operating in electrically noisy environments.

Extended Mid-Infrared Range: 2 to 14 µm via Si-ARC Window

The Si-ARC window provides the broadest transmission range of any windowed HIS20SMD variant, covering 2–14 µm. This encompasses the absorption fingerprints of a wide range of gases and organic compounds including CO₂ (4.26 µm), CO (4.6 µm), CH₄ (3.3 µm), N₂O (4.5 µm), ammonia/NH₃ (10.3 µm), ozone/O₃ (9.6 µm), SO₂ (7.3 µm), and complex VOCs absorbing in the 8–14 µm region. This makes the HIS20SMD-S the most versatile windowed emitter in the HIS20SMD range.

Silicon Anti-Reflection Coating for Maximum Optical Throughput

The anti-reflection coating on the silicon window minimises surface reflection losses, maximising the fraction of emitted infrared radiation that reaches the detector. This results in higher effective optical power at the detector compared to uncoated silicon windows, improving signal quality in sensitivity-critical applications.

Gold-Plated SMD Package for Long-Term Reliability

The gold-plated package ensures stable, corrosion-resistant electrical contacts over the device lifetime. This is particularly important for instruments deployed in humid, chemically active, or industrial environments where oxidation of contact surfaces could degrade measurement performance over time.

Near Black-Body Emission with Emissivity > 0.9

The patented nanostructured emitter surface achieves emissivity exceeding 0.9, delivering strong, reproducible infrared output that closely approximates an ideal thermal radiator across the full 2–14 µm window. This ensures consistent detector illumination and measurement repeatability across the product lifetime.

Compact 3 × 3 mm SMD Package — Production Ready

The miniature surface-mount form factor integrates into standard PCB designs and is compatible with automated pick-and-place and reflow soldering assembly. Indian OEM manufacturers can adopt the HIS20SMD-S directly into production lines for gas detection instruments, environmental analysers, and industrial safety systems.

Low Power Operation — 175 mW Maximum

With a maximum power consumption of 175 mW and a 1.25 V operating voltage, the HIS20SMD-S is suitable for portable battery-operated instruments, field-deployable monitoring systems, and embedded IoT sensing nodes where minimising power draw is essential.

Pulsable Output — Modulation up to 14 Hz

Support for modulated operation enables synchronous detection and lock-in amplifier techniques, significantly reducing thermal background noise and improving measurement precision. This feature is essential in trace gas analysers and environmental monitoring instruments requiring detection at parts-per-million (ppm) or parts-per-billion (ppb) concentration levels.

JEDEC-Compliant Mechanical and Thermal Durability

Compliance with three JEDEC reliability standards confirms the component’s suitability for demanding industrial, environmental, and commercial applications with high requirements for mechanical robustness and thermal cycling durability.

Evaluation Accessories Available

The HIS20SMD-S is supported by the DCB.S3.175 Driver Circuit Board and BOB 0.4 Breakout Board, enabling rapid system evaluation and prototyping with minimal additional circuitry. Both accessories are available through United Spectrum Instruments.

Environmental Monitoring

Used in NDIR gas sensors to measure atmospheric gases such as carbon dioxide, methane, and hydrocarbons.

Industrial Safety and Gas Detection

Installed in gas monitoring systems used in chemical plants, refineries, and manufacturing facilities to detect hazardous gases.

Smart Buildings and HVAC Systems

Supports indoor air quality monitoring in smart building automation and HVAC control systems.

Medical and Healthcare Diagnostics

Integrated into respiratory gas analysis systems, breath alcohol analysers, and medical monitoring equipment.

Consumer Electronics and IoT

Used in compact portable gas sensors, smart home devices, and wearable sensing technologies.

Scientific Research and Analytical Instruments

Used in infrared spectroscopy systems, portable spectrometers, and laboratory research instruments

United Spectrum Instruments is a specialised photonics and sensing technology company serving India’s research, industrial, and manufacturing sectors. As the authorised Indian distributor for the complete INFRASOLID HISsmd series, the team offers genuine components backed by manufacturer-certified expertise and responsive local support.

• Official authorisation: Verified product authenticity with full manufacturer traceability and warranty coverage
• Technical consultation: Expert application guidance on Si-ARC window optics, multi-gas sensor design, detector and filter selection, and modulation parameter optimisation
• Application engineering: End-to-end support for NDIR multi-gas sensor development, environmental analyser integration, industrial safety system design, and research instrument prototyping
• Full HISsmd series availability: Supply of HIS20SMD-S, HIS20SMD-A, HIS20SMD-0, and other variants — plus accessories including DCB.S3.175 driver boards and BOB 0.4 breakout boards
• Fast domestic supply: Pan-India logistics with reduced lead times and domestic import handling
• Institutional procurement support: GST-compliant invoicing, purchase order processing, and documentation for government departments, public sector undertakings, research institutions, and corporate procurement
• Nationwide coverage: Serving all major technology and industrial hubs across India including Bengaluru, Hyderabad, Delhi NCR, Mumbai, Chennai, Pune, Ahmedabad, and Kolkata