The HIS100SMD-A operates on the same fundamental principle as all HISsmd emitters: a micro-fabricated resistive heating element — constructed from a high-melting-point metal with a proprietary nanostructured high-emissivity surface coating — is electrically heated to approximately 600 °C at maximum drive power (290 mW). At this temperature, the element emits broadband infrared radiation closely approximating a near black-body spectrum, which is then transmitted through the integrated sapphire optical window.

The sapphire (Al₂O₃) window selectively transmits the 2 to 6 µm infrared range — the spectral region that contains the primary molecular absorption bands of the most commercially important gases: CO₂ at 4.26 µm, CO at 4.6 µm, methane (CH₄) at 3.3 µm, nitrous oxide (N₂O) at 4.5 µm, ethanol at approximately 3.4 µm, and a range of hydrocarbons. By restricting the emitted spectrum to this band, the sapphire window maximises the fraction of optical power useful to the detector while blocking longer-wave thermal radiation that would otherwise add to detector background noise without contributing to the measurement signal.

The 1 mm² radiating element — a 3× increase in area over the HIS20SMD variants — delivers proportionally greater total radiant flux within the 2–6 µm window. This significantly higher IR power enables system designers to use longer optical path lengths in gas cells (increasing Beer-Lambert absorption sensitivity), illuminate larger detector areas or detector arrays, achieve adequate SNR with lower-cost or less sensitive detectors, or maintain robust measurement performance in fouled or contaminated optical environments where IR transmission is attenuated.

Modulated operation is supported up to 10 Hz (50% modulation depth, square wave, 50% duty cycle). This enables lock-in detection for improved signal-to-noise performance. The 10 Hz modulation limit — lower than the 14 Hz of the HIS20SMD-A — reflects the larger thermal mass of the 1 mm² element.

Highest Optical Output of Any Windowed HISsmd Emitter — Up to 22 mW

The HIS100SMD-A delivers up to 22 mW of optical output within the 2–6 µm sapphire window — exactly twice the output of the HIS20SMD-A (11 mW) and more than 50% higher than the HIS20SMD-S (13 mW). This makes it the highest-power windowed emitter in the HISsmd range, providing the greatest detector signal margin for any gas sensing application targeting the 2–6 µm band.

Large 1 mm² Radiating Element for Maximum Radiant Flux

The 1 × 1 mm element is three times the area of the HIS20SMD variants. The larger emitting surface provides higher total radiant flux and greater etendue, enabling effective illumination of larger optical apertures, long gas cells, and multi-detector optical architectures. This is particularly beneficial in high-performance NDIR analysers, multi-channel gas sensors, and instruments designed for long-term field deployment in challenging optical environments.

Sapphire Window — Precise 2–6 µm Spectral Bandpass

The sapphire (Al₂O₃) optical window provides excellent transmission from 2 to 6 µm, covering the primary absorption fingerprints of all major commercially important gases including CO₂, CO, CH₄, N₂O, and ethanol. The sapphire window simultaneously blocks longer-wave thermal radiation, improving detector signal quality by reducing thermal background contributions from the emitter beyond the measurement band. Sapphire’s exceptional hardness (Mohs 9) and chemical inertness ensure the window maintains its optical properties across the product lifetime, even in humid or mildly corrosive environments.

Gold-Plated Package for Reliable High-Current Operation

The gold-plated SMD package provides stable, corrosion-resistant electrical contacts rated for continuous operation at up to 170 mA. Gold plating is particularly important at the HIS100SMD-A’s higher drive current levels, where contact oxidation or resistance drift would more significantly impact emitter drive stability and measurement reproducibility than at lower current levels.

Near Black-Body Emission with Emissivity > 0.9

The patented nanostructured radiating surface achieves emissivity exceeding 0.9, delivering well-characterised, reproducible infrared output that closely approximates an ideal thermal radiator. This ensures accurate, consistent detector illumination across the product lifetime and between components in production environments.

Pulsable Operation — Modulation up to 10 Hz

Modulated output enables synchronous lock-in detection for improved signal-to-noise ratio in sensitive gas measurement applications. The 10 Hz maximum modulation frequency is fully adequate for NDIR gas sensing, capnography, breath analysis, and most analytical instrument designs.

JEDEC-Compliant Mechanical and Thermal Reliability

Full compliance with three JEDEC reliability standards confirms the component’s suitability for industrial and commercial applications with demanding mechanical and thermal operating conditions.

Supported by DCB.S3.290 Driver Circuit Board and BOB 0.4 Breakout Board

The dedicated DCB.S3.290 Driver Circuit Board (LT3065 LDO regulator, 2.0–13 V input, 290 mW drive power) enables rapid evaluation and prototyping. The BOB 0.4 Breakout Board adapts the SMD footprint to standard 2.54 mm pitch headers for bench development. Both accessories are available through United Spectrum Instruments.

Production-Ready 3 × 3 mm SMD Footprint

The same SMD footprint shared across the HISsmd range enables drop-in adoption in PCB designs previously using other HISsmd variants, and full compatibility with automated pick-and-place assembly and reflow soldering for high-volume manufacturing.

Environmental Monitoring

Used in NDIR gas sensors for monitoring atmospheric gases such as CO₂ and methane.

Industrial Safety & Gas Detection

Integrated into gas detection systems used in chemical plants, refineries, and industrial facilities.

Smart Buildings & HVAC

Used in indoor air quality monitoring systems for building automation and HVAC control.

Medical & Healthcare Diagnostics

Supports respiratory gas analysis systems and breath alcohol detection instruments.

Consumer Electronics & IoT

Used in portable gas sensors, wearable environmental monitors, and smart home devices.

Scientific Research & Spectroscopy

Integrated into infrared spectroscopy systems, portable spectrometers, and laboratory 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 full INFRASOLID HISsmd product range, the team provides genuine components backed by manufacturer-certified expertise, local application engineering, and responsive after-sales service.

• Official authorisation: Verified product authenticity with full manufacturer traceability and warranty coverage for all INFRASOLID products
• Technical consultation: Expert guidance on high-power NDIR sensor design, sapphire window optics, detector and bandpass filter selection, modulation optimisation, and PCB thermal management
• Full HISsmd series availability: Complete range: HIS100SMD-A, HIS100SMD-0, HIS20SMD-A, HIS20SMD-0, HIS20SMD-S — plus DCB.S3.290, DCB.S3.175, and BOB 0.4 accessories
• Application engineering support: End-to-end guidance for NDIR sensor integration, medical device development, industrial analyser design, and research instrumentation prototyping
• Fast domestic supply: Pan-India logistics with reduced lead times and complete import documentation and GST compliance handling
• Institutional procurement: Purchase order processing and documentation for IITs, NITs, CSIR, DRDO, ISRO, government departments, and corporate procurement teams
• Nationwide coverage: Bengaluru, Hyderabad, Delhi NCR, Mumbai, Chennai, Pune, Ahmedabad, Kolkata, and all major technology and industrial hubs across India