Vishay Semiconductor Opto Division VLDK1235R

Overview

VLDK1235R from Vishay Semiconductors is an orange-red dome lens surface-mount LED using AlInGaP-on-Si chip technology, delivering 9000–35500 mcd luminous intensity at 50 mA with 611–621 nm dominant wavelength and ±11° viewing angle - deployed in traffic signal indicators and high-visibility signage.

For engineers reviewing the VLDK1235R datasheet, VLDK1235R pinout, VLDK1235R application, or VLDK1235R equivalent, this page provides verified optical-electrical specs, gullwing/reverse gullwing package details, thermal derating curves, JEDEC level 2a reflow compliance, and ESD robustness (2 kV HBM) for reliable indicator design.

Technical Context

The VLDK1235R operates as a single-die, DC-driven visible-light emitter with fixed polarity (anode/cathode), optimized for constant-current drive up to 70 mA at ≤60 °C ambient. Its AlInGaP-on-Si chip delivers stable orange-red emission with spectral bandwidth of 18 nm and luminous flux-to-intensity ratio of 0.5 mlm/mcd.

Thermal resistance junction-to-ambient is 325 K/W when mounted on ≥16 mm² copper pad; forward voltage ranges 1.9–2.7 V at 50 mA with ±0.1 V tolerance. Reverse voltage rating is limited to 5 V for short-term use only, per datasheet Note (1).

Key Specifications

Pinout & Package

Package: SMD dome lens, 2.3 × 2.3 × 2.8 mm body, available in gullwing (VLDK1235G) and reverse gullwing (VLDK1235R) lead configurations. Both variants use exposed copper thermal pad for enhanced heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar orange-red LED applications.

Compared with VLDK1235R, VLDK1235G offers identical photometric performance in a mechanically distinct leadform for layout flexibility, while VLDR1235R shifts dominant wavelength into red - making it functionally distinct for color-critical applications like traffic signals.

Availability

VLDK1235R is available at Aetrix Electronics and suitable for traffic signal systems, industrial control panels, emergency signage, and automotive interior indicators requiring stable component supply, consistent binned luminous intensity, and JEDEC-compliant reflow processing.

Supply support for VLDK1235R includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Vishay Semiconductors designs and manufactures discrete semiconductors including diodes, MOSFETs, optoelectronics, and power ICs, with global manufacturing and test facilities focused on high-reliability components.

The VLDK1235R belongs to Vishay's VLD.1235 dome lens SMD LED product line, engineered for high-brightness, narrow-viewing-angle visible indicators in transportation, industrial, and safety-critical applications.

FAQ

What is the maximum continuous forward current for VLDK1235R?

The VLDK1235R supports a maximum DC forward current of 70 mA when ambient temperature is ≤60 °C. At higher temperatures, derating is required per Figure 1 in the datasheet; for example, at 85 °C ambient, the permissible current drops to approximately 45 mA to maintain junction temperature ≤125 °C. This limit ensures long-term reliability and lumen maintenance.

Does VLDK1235R require external current limiting?

Yes, VLDK1235R requires external current limiting - typically a series resistor or constant-current driver - because it is a passive diode device with nonlinear V_F-I_F characteristics. At 50 mA, forward voltage is 1.9–2.7 V; using a 5 V supply, a 62 Ω resistor (±5 %) achieves nominal bias, accounting for V_F tolerance and thermal drift.

Is VLDK1235R compatible with lead-free reflow soldering?

Yes, VLDK1235R is qualified for lead-free reflow per J-STD-020, with a peak temperature of 245 °C (max 260 °C for ≤10 s). The recommended profile includes ramp-up ≤3 °C/s, time above 217 °C of 60–150 s, and cooling rate ≤6 °C/s. Preconditioning to JEDEC level 2a is applied, so unopened reels may be processed directly if used within 672 hours of opening.

What does the "R" suffix in VLDK1235R indicate?

The "R" suffix in VLDK1235R denotes the reverse gullwing lead configuration - where leads extend downward from the bottom of the package body, enabling bottom-side mounting and improved mechanical stability in high-vibration environments. This contrasts with the "G" suffix (gullwing), where leads bend outward from the sides. Both share identical optical, electrical, and thermal specifications.

Can VLDK1235R be used in reverse-bias conditions?

VLDK1235R permits reverse voltage up to 5 V, but only for short-term applications as explicitly stated in the datasheet Note (1). Continuous or repeated reverse bias risks permanent degradation of the AlInGaP chip. It must never be used as a bidirectional device or in AC-coupled circuits without series protection diodes.