HSMG-C191 LED Application Guide

flux

I’ll research the HSMG-C191 manufacturer specifications, practical LED drive circuits, and sourcing alternatives, then save a cited application guide in the project files.

flux

The source listings conflict with this project’s description: they identify a yellow-green LED rather than a 527 nm device. Datasheet verification is still pending, so I’ll clearly flag unresolved specifications and avoid presenting replacement parts as verified drop-ins.
Created a project doc

HSMG-C191 Application and Usage Guide

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HSMG-C191 Application and Usage Guide
Broadcom’s HSMG-C191 is a low-profile, two-terminal, surface-mount ChipLED in the 0603 package family (manufacturer product page). Its usual circuit role is a current-limited status indicator or compact backlight; the green color and optical specifications below remain provisional until datasheet verification completes.
Verification status — research draft, not a release-approved specification. The manufacturer datasheet endpoint did not return an accessible PDF, and verification of two mirrored copies is still pending. Numerical datasheet claims are therefore explicitly marked unverified; links identify the source to check, not compl...

flux

I saved the HSMG-C191 Application and Usage Guide in the project files, covering all seven requested sections and source links. It remains a research draft: datasheet verification could not complete, so unresolved ratings and replacement compatibility are explicitly flagged. Distributor listings also conflict with the project’s 527 nm / 3.4 V description; resolving that discrepancy and verifying the datasheet are the next priorities.
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HSMG-C191 Application and Usage Guide
Broadcom’s HSMG-C191 is a low-profile, two-terminal, surface-mount ChipLED in the 0603 package family (manufacturer product page). Its usual circuit role is a current-limited status indicator or compact backlight; the green color and optical specifications below remain provisional until datasheet verification completes.
Verification status — research draft, not a release-approved specification. The manufacturer datasheet endpoint did not return an accessible PDF, and verification of two mirrored copies is still pending. Numerical datasheet claims are therefore explicitly marked unverified; links identify the source to check, not completed verification. Do not release a BOM, footprint, or current rating from this draft alone. Research date: October 7, 2026. No component properties or PCB geometry were changed.
Important metadata discrepancy: the project description says “527 nm, 3.4 V.” The LCSC listing instead reports 572 nm dominant wavelength and 2.2 V forward voltage at a 20 mA test current. Those values are unverified against the datasheet in this session, but the discrepancy must be resolved before designing around the project description.
1. Quick Specifications

Table

ParameterValueClassification and verification status
Manufacturer / MPNBroadcom / HSMG-C191Identity confirmed by the manufacturer product page.
Package0603, low-profile top-mount ChipLEDProduct family confirmed by manufacturer page; exact mechanical drawing remains unresolved.
Nominal body dimensions1.6 × 0.8 × 0.6 mmUnverified datasheet/search-extracted dimensions; manufacturer page category uses 1.6 × 0.88 mm, so use the drawing rather than the category label for CAD. Manufacturer datasheet mirror.
Terminal / land pitchNot establishedUnverified; do not confuse 0603 body size or tape pocket pitch with PCB land-center spacing.
Forward voltage, V_F2.2 V typical at I_F = 20 mAUnverified, reported by LCSC. This is a test-condition characteristic, not a regulated supply voltage. Minimum/maximum limits remain unresolved.
Optical test current20 mAUnverified, reported by LCSC; not established as the absolute maximum or the recommended operating current.
Dominant / peak wavelength572 nm / 570 nmUnverified, reported by LCSC.
Luminous intensity / viewing angle15 mcd / 170°Unverified listing values; intensity is associated with the listed 20 mA test condition. LCSC.
Operating temperature−40°C to +85°CUnverified, reported by LCSC; does not establish full-current operation throughout the range.
Absolute maximum continuous currentUnresolvedUnverified; obtain the HSMG column of the Absolute Maximum Ratings table before release.
Absolute maximum pulsed currentUnresolvedUnverified; pulse width, duty cycle and derating conditions must accompany any limit.
Absolute maximum reverse voltageUnresolvedUnverified; design for no intentional reverse bias until confirmed.
Absolute maximum power dissipationUnresolvedUnverified; JLCPCB lists 52 mW, but its classification and datasheet conditions have not been validated.
Storage / junction temperature and thermal deratingUnresolvedUnverified; do not infer these from the operating-temperature range.
Initial indicator-current target2–5 mA, subject to validationEngineering starting point, not a manufacturer recommended operating condition. Verify visibility, current limits and temperature behavior on samples.
Absolute maximum ratings are stress limits, not design targets. A complete verified ratings table is still required; this document does not substitute typical or distributor values for maximum limits.
2. Pinout & Connections

Table

Pin NumberPin NameDescriptionBest Practice
Not verifiedA — anodePositive terminal for forward conductionConnect to the positive supply or sourcing output through a series resistor. Confirm the symbol-to-pad mapping rather than assuming a numbering convention.
Not verifiedK — cathodeNegative terminal for forward conductionConnect to GND for a steady indicator, or to a suitable low-side switch / sinking GPIO for control. Confirm package polarity before assembly.
The manufacturer datasheet search extract labels the HSMx-C191 polarity feature as a cathode mark, with an anode-mark exception for HSMH-C191. This marking detail remains unverified against the package drawing; do not apply the HSMH exception to HSMG without checking the exact drawing. Broadcom datasheet mirror.
Physical terminal numbers and the current Flux part’s pad mapping were not validated. Do not publish “pin 1 = cathode” or “pin 2 = anode” as a manufacturer fact without that check.
3. Standard Application Circuit
Steady power indicator
Text
V_SUPPLY ── R_SERIES ── A |>| K ── GND
Use one series resistor per LED branch. This discrete LED does not require an LED-local bypass capacitor, pull-up, or pull-down; decouple any driving IC according to that IC’s datasheet.
GPIO control
For active-high control, wire GPIO → resistor → anode, with cathode to GND. Verify the MCU’s guaranteed loaded V_OH, per-pin source-current limit and total port-current budget before choosing the current.
For active-low control, wire supply → resistor → anode, with cathode to a GPIO that is specified to sink the chosen current. Use only a supply/output combination that does not overvoltage the GPIO in the LED-off or MCU-unpowered states. To control a 5 V LED branch from a 3.3 V MCU, a suitable low-side transistor or MOSFET avoids relying on unspecified GPIO tolerance; verify the switch’s logic-drive specification and add a gate/base bias resistor if needed for a defined reset state.
Series-resistor calculation for 3.3 V and 5 V logic
These are illustrative engineering calculations, not manufacturer application-circuit recommendations. They use the unverified 2.2 V typical V_F at 20 mA from the LCSC listing; actual V_F at 2–5 mA will differ.
For an ideal voltage source:
R_SERIES = (V_SUPPLY − V_F) / I_LED
For GPIO drive, replace V_SUPPLY with guaranteed loaded V_OH when sourcing, or use R_SERIES = (V_SUPPLY − V_F − V_OL) / I_LED when sinking.

Table

RailAssumed target currentCalculation using V_F = 2.2 VExample resistorCalculated current at the assumed V_F
3.3 V2 mA(3.3 − 2.2) / 0.002 = 550 Ω560 Ω1.96 mA
3.3 V5 mA(3.3 − 2.2) / 0.005 = 220 Ω220 Ω5.00 mA
5 V2 mA(5 − 2.2) / 0.002 = 1400 Ω1.5 kΩ1.87 mA
5 V5 mA(5 − 2.2) / 0.005 = 560 Ω560 Ω5.00 mA
For a bench starting point, select 560 Ω on 3.3 V or 1.5 kΩ on 5 V, then measure LED current and visibility. Do not interpret these nominal calculations as guaranteed current limits.
Worst-case selection must include rail tolerance, resistor tolerance, minimum V_F at the intended current and temperature, and driver voltage drop:
I_MAX = (V_RAIL_MAX − V_F_MIN − V_DRIVER_MIN) / R_MIN
P_R = I_LED² × R_SERIES
At the illustrative 5 V / 560 Ω operating point, nominal resistor dissipation is 14 mW. As an additional conservative sizing illustration, assuming a 5 V rail with +5% tolerance and a 560 Ω ±1% resistor, even a shorted LED gives P_R = 5.25² / (560 × 0.99) ≈ 49.7 mW; a 0.125 W resistor has nominal margin, but its temperature derating must still be checked. These rail/resistor tolerances are explicit design assumptions, not component specifications.
Do not calculate a resistor using the project’s 3.4 V description until the discrepancy is resolved: it would falsely imply no useful voltage headroom from a 3.3 V rail.
4. PCB Layout & Routing Guidelines
  • Use the exact land pattern, not only a generic “0603” label. The retrieved manufacturer document identifies Figure 13 as the recommended soldering pattern for C190/C191/C197, but its pad dimensions remain unverified. Check that drawing, terminal geometry and polarity against the actual Flux footprint before fabrication. Datasheet mirror.
  • Keep both pads thermally balanced. Similar copper area and trace entry reduce unequal solder heating and tombstoning risk. When a pad connects to a large pour, use an assembly-appropriate thermal connection instead of creating a strong copper imbalance. This is general PCB assembly guidance, not a part-specific manufacturer rule.
  • Route for indicator current rather than power-LED current. A short 0.20 mm trace is a practical engineering starting point for a 2–5 mA branch; follow the selected JLCPCB manufacturing rules. No differential-pair routing or controlled impedance applies to this two-terminal indicator.
  • Place the resistor nearby and protect visibility. Keep the switched loop compact, mark cathode polarity on assembly documentation, and preserve optical clearance for any light pipe, diffuser or enclosure aperture. Avoid placing hot power components immediately beside the indicator.
  • Validate the assembly process. Reflow temperature limits, exposure duration and moisture handling remain unresolved. Do not copy the profile or MSL from another color or supplier. No LED-local decoupling capacitor is required; any transistor/driver supply decoupling belongs near that driver’s power pins.
5. Common Pitfalls / Things to Watch Out For
  1. Driving the LED as a voltage load or using the wrong metadata. Omitting the series resistor, treating typical V_F as a supply rating, or calculating from the project’s 527 nm / 3.4 V description can produce an incorrect circuit. Use current limiting, validate the actual part, and account for GPIO loading and temperature.
  2. Assuming every green 0603 LED is a drop-in replacement. Polarity marking, pad mapping, height, color, intensity, viewing angle, forward voltage and assembly requirements can differ. Validate electrical current and optical appearance as well as solderability; do not transfer another family member’s polarity-mark exception blindly.
6. Popular Alternatives & Equivalents
No verified drop-in replacement is established by this research. The following are primary-source-supported candidate families, but their detailed datasheet verification and footprint comparison remain open; they must not be released as approved equivalents.

Table

CandidateManufacturerCompatibility classificationWhat must be checked
APT1608SGCKingbrightFunctionally similar candidate only; pin/footprint compatibility not verifiedThe manufacturer datasheet search extract reports 1.6 × 0.8 × 0.75 mm, 568 nm dominant wavelength, 2.2 V typical / 2.5 V maximum at 20 mA, and 150° viewing angle — all unverified in this session. It is taller and has a different optical distribution than the provisional HSMG values. Manufacturer datasheet. Exact MPN not confirmed in the Flux search results; no library availability claimed.
VLMG1300-GS08VishayFunctionally similar candidate only; pin/footprint compatibility not verifiedManufacturer search extract reports yellow-green emission, 571 nm dominant wavelength, 2.0 V typical / 2.4 V maximum at 20 mA and 130° viewing angle — all unverified in this session. Recalculate current and compare the mechanical drawing and optical intensity. Manufacturer datasheet. Exact MPN not confirmed in the Flux search results; do not confuse it with blue VLMB1300 or 0402 VLMG1500.
A different Kingbright part, APT1608CGCK, was confirmed present in the Flux library, but it is not APT1608SGC and has not been evaluated as an equivalent here. Library search presence alone is not an engineering compatibility assessment.
Approve a substitute only after reviewing its exact datasheet, polarity/pad mapping, recommended land pattern, height, current limits, optical binning and reflow/moisture conditions, then testing it in the intended enclosure.
7. Sourcing & Purchasing Guide

Table

AttributeDetails
Primary DistributorsCheck DigiKey and Mouser for traceable Broadcom stock and confirm current franchise status through Broadcom. Exact live DigiKey/Mouser purchasing terms were not verified. An LCSC listing and JLCPCB assembly listing were located for C7466703; listing presence alone does not establish authorization or available stock.
Packaging OptionsManufacturer datasheet search extracts describe tape & reel; distributor cut-tape availability is not directly verified. Full-reel quantity is provisionally 4,000, also reported by JLCPCB. Confirm packaging at quotation time.
Standard MOQNo universal MOQ verified. JLCPCB’s retrieved listing showed minimum 33 and full reel 4,000, with stock 0 on the research date; these are platform purchasing conditions, not the manufacturer’s universal MOQ. Do not assume “1 unit cut tape” without checking the chosen distributor.
Sourcing AdvicePrefer manufacturer-franchised channels and traceable lot/date codes; avoid untraceable broker or marketplace stock. Confirm exact HSMG-C191 ordering code, color/intensity bin requirements, reel quantity, and any supplier-specific packaging suffix. For JLCPCB assembly, recheck C7466703 availability and assembly eligibility before committing the BOM.
Moisture / handlingJLCPCB reports MSL 3, but the exact manufacturer handling classification was not validated. Use the actual sealed bag label and current manufacturer instructions; do not assume floor life from a listing.
Stock, MOQ, packaging options and distributor status can change. This document contains no firm procurement quote or verified lifecycle determination.
Sources
Manufacturer and manufacturer-authored documents
Distributor / assembly-platform sources
Remaining verification work
Complete citation-backed datasheet extraction for the HSMG-C191 absolute limits, forward-voltage limits, optical characteristics, derating, mechanical drawing, cathode mark, soldering pattern, reflow/moisture handling and document revision. Inspect the current Flux symbol/pad mapping; compare candidate footprints; and confirm distributor cut-tape MOQ before publication as a fully verified application guide.

  • 1. Quick Specifications

  • 2. Pinout & Connections

  • 3. Standard Application Circuit

  • Steady power indicator

  • GPIO control

  • Series-resistor calculation for 3.3 V and 5 V logic

  • 4. PCB Layout & Routing Guidelines

  • 5. Common Pitfalls / Things to Watch Out For

  • 6. Popular Alternatives & Equivalents

  • 7. Sourcing & Purchasing Guide

  • Sources

  • Manufacturer and manufacturer-authored documents

  • Distributor / assembly-platform sources

  • Remaining verification work