IN-S42ATB

Summary

every figure cited to the datasheet below

0402 top-view SMD LED in a clear-lens, PCB-type moulded package — 1.0 × 0.5 × 0.45 mm^{p.1, p.8}
InGaN blue emitter — dominant wavelength 470 nm, peak wavelength 468 nm^{p.3, p.7}
Forward voltage 3.1 V typ (4.0 V max) at the 20 mA test current^p.3
Luminous intensity 100 mcd typ at 20 mA^{p.3, p.7}
120° viewing angle (2θ_1/2) — the one member of the series rated below 130°^p.3
25 mA max continuous forward current; 100 mA peak at 1/10 duty, 0.1 ms pulse^p.2
5 V max reverse voltage; 100 mW max power dissipation^p.2
Operating −30 to +80 °C, storage −40 to +85 °C^p.2
Moisture sensitive and ESD sensitive (InGaN) — ships dry-packed in a sealed moisture-barrier anti-static bag^{p.2, p.11}
Supplied on tape and reel, 5000 pcs per reel^p.9

IN-S42ATB is the blue member of Inolux's IN-S42AT series: a low-profile 0402 top-view indicator LED in a clear, PCB-type moulded package.^p.1 The die is InGaN^p.7 at a dominant wavelength of 470 nm, returning 100 mcd at the 20 mA test point.^p.3

The number to respect is the forward-voltage spread: 3.1 V typ but up to 4.0 V max.^p.3 On a 3.3 V rail a typical part leaves 0.2 V for the resistor and a high-V_F part will not reach rated current at all — treat this as a 5 V-rail part, where (5 − 3.1) / 0.02 = 95 Ω sets the full 20 mA. Use a current-limiting resistor — the datasheet asks for one explicitly^p.12 — and keep continuous current at or below 25 mA.^p.2

Blue is the only member of the series with a 120° viewing angle rather than 130°^p.3 — still a wide-angle indicator. InGaN chips are static-sensitive devices, so ESD precautions apply in design and assembly,^p.2 and reverse voltage is rated to only 5 V.^p.2