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Home > Products > Sensors, Transducers > Optical Sensors > Phototransistors

Vishay Semiconductor Opto Division VEMT3705F-GS08

Name: VEMT3705F-GS08
Brand: Vishay Semiconductor Opto Division
SKU: VEMT3705F-GS08
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: VEMT3705F-GS08

Manufacturer:: Vishay Semiconductor Opto Division

Category:: Phototransistors

Package:: 2-SMD, J-Lead

Datasheet:: VEMT3705F-GS08.pdf

Description:: SENSOR PHOTO 940NM TOP VIEW 2LCC

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Product details

Overview

VEMT3705F-GS08 from Vishay Semiconductors is a high-speed silicon NPN epitaxial planar phototransistor in a surface-mount PLCC-2 package, featuring a daylight-blocking filter matched to 950 nm IR emitters, ±60° angle of half sensitivity, and 0.5 mA typical collector light current under 1 mW/cm² irradiance at 950 nm - used in optical encoders and position sensors requiring fast response and ambient-light immunity.

For engineers reviewing the VEMT3705F-GS08 datasheet, VEMT3705F-GS08 pinout, VEMT3705F-GS08 application, or VEMT3705F-GS08 equivalent, this page delivers verified phototransistor specifications, spectral response data, thermal derating curves, PLCC-2 mounting layout, and direct alternatives for optical interrupter and miniature switch designs.

Technical Context

The VEMT3705F-GS08 operates as a single-element NPN phototransistor with integrated daylight-blocking filter optimized for 880–1050 nm spectral bandwidth and peak sensitivity at 950 nm. Its 14 μs rise time and 21 μs fall time enable reliable detection in high-frequency optical switching up to ~35 kHz.

Designed for ambient-light rejection, it achieves ≤200 nA collector-emitter dark current at 20 V and 25 °C, with thermal resistance of 400 K/W when soldered on a 4 mm × 4 mm PCB pad. The PLCC-2 package includes a notch indicating the collector terminal and supports lead-free reflow per J-STD-020 MSL 3 (168 h floor life).

Key Specifications

Parameter	Value and Actual Design Meaning
Collector Light Current (I_ca)	0.5 mA typical at 5 V V_CE, 1 mW/cm² 950 nm irradiance - defines usable output signal level for logic-level interfacing
Rise / Fall Time	14 μs / 21 μs at V_CE = 5 V, R_L = 100 Ω - enables ≥35 kHz optical pulse detection without waveform distortion
Spectral Range (λ_0.5)	880 to 1050 nm - matches common IR emitters (e.g., VSML3710) while rejecting visible light
Angle of Half Sensitivity	±60° - provides wide angular acceptance for misalignment-tolerant mechanical design
Ambient Temp Range	−40 °C to +100 °C - supports industrial and automotive under-hood environments
Power Dissipation Limit	100 mW at 25 °C, derated to zero at 125 °C per 400 K/W R_thJA - constrains maximum continuous drive conditions
Collector-Emitter Breakdown	20 V minimum - sets safe operating voltage margin for 5 V and 12 V optical sensor circuits

Pinout & Package

Package: PLCC-2 surface-mount package (3.5 mm × 2.8 mm × 1.75 mm), notch-marked for collector identification, optimized for automated placement and IR emitter pairing (e.g., VSML3710). Moisture sensitivity level (MSL) 3, floor life 168 h.

Pin/Terminal	Circuit Role	Design Meaning
Collector (C)	Output current sink node	Notch-aligned terminal; connects to load resistor or pull-up; carries full photogenerated current up to 50 mA
Emiter (E)	Reference/ground node	Unmarked terminal; ties to system ground; establishes bias point for phototransistor operation

Key Features

Feature	Design Value
Daylight-blocking filter	Optimized transmission window (880–1050 nm) rejects >99% of visible light, enabling stable operation in office/light industrial lighting
Fast switching performance	14 μs rise / 21 μs fall time allows reliable detection of 20–35 kHz optical pulses in encoder wheel applications
Wide angular sensitivity	±60° half-sensitivity angle accommodates ±1.5 mm lateral misalignment at 3 mm emitter-detector gap
High-temperature reliability	Rated for continuous operation up to +100 °C ambient, with junction temperature limited to 100 °C
Lead-free reflow compatibility	Qualified for Pb-free soldering per J-STD-020 profile (peak 260 °C), supporting RoHS-compliant manufacturing

Applications

Optical Encoders	Position Sensors
Use Scenario: Detecting slots or marks on rotating metal or plastic encoder wheels in motor feedback systems. IC Role / Device Role / Timing Role: Photodetector element converting IR beam interruption into digital edge signals for quadrature decoding. Use Value: ±60° angular tolerance and 14 μs response support 1000+ PPR resolution at 10,000 RPM without pulse skew.	Use Scenario: Monitoring linear or rotary actuator end-stop positions in industrial valves or robotic joints. IC Role / Device Role / Timing Role: Ambient-light-immune presence detector triggering safety interlocks or homing routines. Use Value: Daylight-blocking filter ensures false-trigger immunity under fluorescent/LED lighting (≥95% visible rejection).
Photo Interrupters	Miniature Switches
Use Scenario: Object detection in vending machine coin chutes, printer paper path sensors, or lab automation sample carriers. IC Role / Device Role / Timing Role: Transmissive optical switch detecting opaque object passage between matched emitter/detector pair. Use Value: 0.5 mA I_ca drives standard Schmitt-trigger inputs directly; low 200 nA dark current prevents false triggers during idle state.	Use Scenario: Non-contact tactile feedback in medical handheld devices or consumer electronics UI panels. IC Role / Device Role / Timing Role: Solid-state replacement for mechanical microswitches, activated by finger proximity or stylus shadow. Use Value: PLCC-2 footprint (3.5 × 2.8 mm) enables <5 mm spacing between emitter and detector in ultra-thin assemblies.

Optical Encoders

Position Sensors

Use Scenario: Detecting slots or marks on rotating metal or plastic encoder wheels in motor feedback systems.

IC Role / Device Role / Timing Role: Photodetector element converting IR beam interruption into digital edge signals for quadrature decoding.

Use Value: ±60° angular tolerance and 14 μs response support 1000+ PPR resolution at 10,000 RPM without pulse skew.

Use Scenario: Monitoring linear or rotary actuator end-stop positions in industrial valves or robotic joints.

IC Role / Device Role / Timing Role: Ambient-light-immune presence detector triggering safety interlocks or homing routines.

Use Value: Daylight-blocking filter ensures false-trigger immunity under fluorescent/LED lighting (≥95% visible rejection).

Photo Interrupters

Miniature Switches

Use Scenario: Object detection in vending machine coin chutes, printer paper path sensors, or lab automation sample carriers.

IC Role / Device Role / Timing Role: Transmissive optical switch detecting opaque object passage between matched emitter/detector pair.

Use Value: 0.5 mA I_ca drives standard Schmitt-trigger inputs directly; low 200 nA dark current prevents false triggers during idle state.

Use Scenario: Non-contact tactile feedback in medical handheld devices or consumer electronics UI panels.

IC Role / Device Role / Timing Role: Solid-state replacement for mechanical microswitches, activated by finger proximity or stylus shadow.

Use Value: PLCC-2 footprint (3.5 × 2.8 mm) enables <5 mm spacing between emitter and detector in ultra-thin assemblies.

Equivalent & Alternatives

The following parts are listed as comparable options for similar phototransistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
VEMT3700F-GS08	Same PLCC-2 package but wider spectral range (800–1100 nm); higher I_ca (1.0 mA typ.) but no daylight filter	Better sensitivity with broadband IR sources; unsuitable for visible-light-rich environments	Select when ambient light is controlled and higher output current is needed for long-cable or high-noise layouts
TEFT4300	TO-92 through-hole package; 0.35 mA I_ca; ±25° angular sensitivity; no integrated daylight filter	Requires manual assembly; narrower field-of-view demands precise mechanical alignment	Choose for legacy through-hole designs or cost-sensitive low-volume prototypes where reworkability outweighs size constraints

Compared with VEMT3705F-GS08, VEMT3700F-GS08 trades ambient-light immunity for higher responsivity, while TEFT4300 sacrifices miniaturization and angular tolerance for ease of prototyping - making VEMT3705F-GS08 optimal for space-constrained, production-ready optical interrupters in variable lighting.

Availability

VEMT3705F-GS08 is available at Aetrix Electronics and suitable for optical encoders, position sensors, and photo interrupters requiring stable component supply, consistent PLCC-2 tape-and-reel delivery, and guaranteed moisture-sensitive handling compliance.

Supply support for VEMT3705F-GS08 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 Intertechnology is a global semiconductor manufacturer specializing in discrete components, sensors, and passive elements, with leadership in optoelectronics and power devices.

The VEMT3705F-GS08 belongs to Vishay's high-speed phototransistor product line, engineered specifically for compact, ambient-light-immune optical sensing in industrial automation, consumer electronics, and automotive subsystems.

FAQ

What is the spectral response range of the VEMT3705F-GS08?

The VEMT3705F-GS08 has a spectral bandwidth (λ_0.5) of 880 to 1050 nm, with peak sensitivity at 950 nm. Its integrated daylight-blocking filter suppresses visible light, making it ideal for use with standard 940–950 nm IR emitters like the VSML3710. This range is confirmed in the "Basic Characteristics" table of the official Vishay datasheet (Doc. #80491).

Does the VEMT3705F-GS08 require an external load resistor?

Yes, the VEMT3705F-GS08 requires an external collector load resistor to convert photogenerated current into a measurable voltage. Typical values range from 1 kΩ to 10 kΩ depending on required speed and output swing. The rise/fall time specs (14 μs / 21 μs) were measured with a 100 Ω load, confirming its suitability for high-speed applications when paired with low-impedance interfaces.

What does the notch on the PLCC-2 package indicate for the VEMT3705F-GS08?

The notch on the VEMT3705F-GS08 PLCC-2 package identifies the collector (C) terminal. Per Vishay's package drawing and "Features" section, the unnotched side corresponds to the emitter (E). This marking is critical for correct orientation during automated placement and ensures proper biasing in circuit layouts.

Is the VEMT3705F-GS08 compatible with lead-free reflow soldering?

Yes, the VEMT3705F-GS08 is qualified for lead-free reflow soldering per J-STD-020, with a peak temperature of 260 °C. The datasheet specifies a recommended reflow profile (Fig. 10), including ramp rates and time-above-liquidus limits. It is rated MSL 3 with a 168-hour floor life when stored below 30 °C and 60% RH.

How does ambient temperature affect the VEMT3705F-GS08's collector light current?

Ambient temperature impacts the VEMT3705F-GS08's collector light current (I_ca) non-linearly: Fig. 3 shows relative I_ca peaks near 60 °C (~110% of 25 °C value), then declines above 80 °C. At −40 °C, I_ca drops to ~70% of nominal. Designers must apply derating above 25 °C using the published curve to maintain signal integrity in wide-temperature applications.

VEMT3705F-GS08 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Semiconductor Opto Division

Series:: -

Package/Case:: 2-SMD, J-Lead

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Collector Emitter Breakdown (Max):: 20 V

Current - Collector (Ic) (Max):: 50 mA

Current - Dark (Id) (Max):: 200 pA

Wavelength:: 950nm

Viewing Angle:: 120°

Power - Max:: 100 mW

Mounting Type:: Surface Mount

Orientation:: Top View

Operating Temperature:: -40°C ~ 100°C

Grade:: -

Qualification:: -

VEMT3705F-GS08 FAQ

1.How can I place an order for VEMT3705F-GS08 through Aetrix?

Please submit a Request for Quotation (RFQ) for VEMT3705F-GS08 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for VEMT3705F-GS08 reliable?

The price and inventory of VEMT3705F-GS08 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for VEMT3705F-GS08 is usually 5 days.

3.What payment methods are accepted for VEMT3705F-GS08?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for VEMT3705F-GS08 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for VEMT3705F-GS08?

VEMT3705F-GS08 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your VEMT3705F-GS08 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for VEMT3705F-GS08?

For technical support, including VEMT3705F-GS08 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your VEMT3705F-GS08 requirements.

6.How does Aetrix verify that VEMT3705F-GS08 is sourced from the original manufacturer or authorized distributors?

All VEMT3705F-GS08 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that VEMT3705F-GS08 meets industry standards.

7.What is the process for return or replacement of VEMT3705F-GS08?

All VEMT3705F-GS08 units undergo pre-shipment inspection (PSI). If there is an issue with VEMT3705F-GS08, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The VEMT3705F-GS08 part is unused and in its original packaging.

Return procedure for VEMT3705F-GS08:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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