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

Vishay Semiconductor Opto Division VEMT3705-GS08

Name: VEMT3705-GS08
Brand: Vishay Semiconductor Opto Division
SKU: VEMT3705-GS08
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: VEMT3705-GS08

Manufacturer:: Vishay Semiconductor Opto Division

Category:: Phototransistors

Package:: 2-SMD, J-Lead

Datasheet:: VEMT3705-GS08.pdf

Description:: SENSOR PHOTO 830NM TOP VIEW PLCC

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Product details

Overview

VEMT3705-GS08 from Vishay Semiconductors is a high-speed silicon NPN epitaxial planar phototransistor in a surface-mount PLCC-2 package, rated for 20 V V_CEO, 0.6 mA typical collector light current (I_ca) at 950 nm, ±60° angle of half sensitivity, and 14 μs rise time - used in optical sensing within photo interrupters and position sensors.

For engineers reviewing the VEMT3705-GS08 datasheet, VEMT3705-GS08 pinout, VEMT3705-GS08 application, or VEMT3705-GS08 equivalent, this page delivers verified phototransistor specifications, spectral response (480–1050 nm), thermal resistance (400 K/W), ambient operating range (−40 to +100 °C), and PLCC-2 mounting layout guidance.

Technical Context

The VEMT3705-GS08 operates as a monolithic NPN phototransistor with epitaxial planar construction, optimized for visible and near-infrared detection (peak λ_p = 950 nm). Its junction-to-ambient thermal resistance of 400 K/W and MSL 3 rating (168 h floor life) define its reflow compatibility and thermal derating behavior on standard PCB pads (4 mm × 4 mm).

It delivers fast switching performance (t_r = 14 μs, t_f = 21 μs) under 5 V V_CE and 100 Ω load, with low dark current (≤200 nA at 20 V) and narrow angular sensitivity (±60°), enabling precise optical coupling in compact encoder and miniature switch designs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	20 V - maximum collector-emitter voltage before breakdown; sets upper limit for biasing in optocoupler or interrupter circuits.
I_ca (typ)	0.6 mA at E_e = 1 mW/cm², λ = 950 nm - defines usable output current level for logic-level interfacing without external amplification.
ϕ (angle)	±60° - field-of-view half-sensitivity angle; determines alignment tolerance between emitter and detector in slotted interrupter assemblies.
t_r/t_f	14 / 21 μs - rise/fall times at V_CE = 5 V, R_L = 100 Ω; enables >10 kHz pulse detection in encoder or counter applications.
λ_0.1	480–1050 nm - spectral bandwidth covering visible blue to near-IR; ensures compatibility with common IR emitters (e.g., VSML3710).
R_thJA	400 K/W - thermal resistance junction-to-ambient on 4 mm × 4 mm pad; requires derating above 25 °C ambient per Fig. 1 power curve.
T_amb	−40 to +100 °C - full operational temperature range; supports industrial and automotive cabin-adjacent sensing environments.

Pinout & Package

Package: PLCC-2 (Plastic Leaded Chip Carrier, 2-terminal), dimensions 3.5 × 2.8 × 1.75 mm, surface-mount, notch-marked for collector identification. Moisture sensitivity level (MSL) 3, lead (Pb)-free reflow compatible (J-STD-020).

Pin/Terminal	Circuit Role	Design Meaning
Collector (notch side)	Anode-side connection of phototransistor output	Notch on PLCC-2 body identifies collector; connects to pull-up resistor or logic input; carries photocurrent under illumination.
Emiter	Cathode-side reference terminal	Common return path for photocurrent; tied to ground or low-side switch node; establishes V_CE bias with collector.

Key Features

Feature	Design Value
Fast response time	14 μs rise / 21 μs fall enables reliable detection of 10–50 kHz optical pulses in rotary encoders and high-speed counters.
Angular sensitivity control	±60° half-sensitivity angle reduces crosstalk in multi-channel sensor arrays and improves positional accuracy in slot-type interrupters.
Spectral match with IR emitters	Peak sensitivity at 950 nm and 480–1050 nm bandwidth aligns with Vishay's VSML3710 emitter series for optimal optical coupling efficiency.
Robust thermal design	Rated for 100 °C junction temperature and 400 K/W R_thJA on standard copper pad - supports continuous operation in sealed industrial housings.
Surface-mount reliability	MSL 3 rating (168 h floor life) and Pb-free reflow profile compliance ensure manufacturability in automated SMT lines without baking delays.

Applications

Photo Interrupters	Miniature Switches
Use Scenario: Slotted optomechanical barrier detecting object presence/absence in vending machines or printer paper-path sensors. IC Role / Device Role / Timing Role: Phototransistor element converting IR beam interruption into digital on/off signal via collector current collapse. Use Value: ±60° angular tolerance allows relaxed mechanical alignment; 0.6 mA I_ca drives standard logic inputs directly without amplification.	Use Scenario: Non-contact tactile feedback in consumer electronics keypads or industrial control panel overlays. IC Role / Device Role / Timing Role: Light-sensitive switch replacing mechanical contacts; activated by finger-induced IR reflection or shadow. Use Value: Fast 14 μs rise time supports responsive user interface sampling; 100 °C max operating temperature accommodates sealed front-panel environments.
Encoders	Position Sensors
Use Scenario: Incremental rotary encoding in motor feedback systems using slotted disk and paired emitter/detector. IC Role / Device Role / Timing Role: High-speed photodetector capturing edge transitions on rotating disk; outputs pulse train proportional to speed/direction. Use Value: 14/21 μs switching enables >10 kHz pulse rates at 360-line resolution; spectral match with 950 nm emitters maximizes SNR.	Use Scenario: Linear or angular position detection in HVAC damper actuators or robotic joint end-stops. IC Role / Device Role / Timing Role: Ambient-light-immune proximity detector triggered by reflected or interrupted IR beam. Use Value: Low 0.2 nA typical dark current minimizes false triggers; −40 to +100 °C rating supports operation inside enclosed mechanical assemblies.

Photo Interrupters

Miniature Switches

Use Scenario: Slotted optomechanical barrier detecting object presence/absence in vending machines or printer paper-path sensors.

IC Role / Device Role / Timing Role: Phototransistor element converting IR beam interruption into digital on/off signal via collector current collapse.

Use Value: ±60° angular tolerance allows relaxed mechanical alignment; 0.6 mA I_ca drives standard logic inputs directly without amplification.

Use Scenario: Non-contact tactile feedback in consumer electronics keypads or industrial control panel overlays.

IC Role / Device Role / Timing Role: Light-sensitive switch replacing mechanical contacts; activated by finger-induced IR reflection or shadow.

Use Value: Fast 14 μs rise time supports responsive user interface sampling; 100 °C max operating temperature accommodates sealed front-panel environments.

Encoders

Position Sensors

Use Scenario: Incremental rotary encoding in motor feedback systems using slotted disk and paired emitter/detector.

IC Role / Device Role / Timing Role: High-speed photodetector capturing edge transitions on rotating disk; outputs pulse train proportional to speed/direction.

Use Value: 14/21 μs switching enables >10 kHz pulse rates at 360-line resolution; spectral match with 950 nm emitters maximizes SNR.

Use Scenario: Linear or angular position detection in HVAC damper actuators or robotic joint end-stops.

IC Role / Device Role / Timing Role: Ambient-light-immune proximity detector triggered by reflected or interrupted IR beam.

Use Value: Low 0.2 nA typical dark current minimizes false triggers; −40 to +100 °C rating supports operation inside enclosed mechanical assemblies.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TEPT5600	TO-92 through-hole package; slower 25 μs rise time; wider ±70° viewing angle; 0.5 mA I_ca (typ).	Requires PCB through-hole mounting; less suitable for space-constrained encoder modules but more tolerant of misalignment.	Select TEPT5600 only when board real estate permits through-hole assembly and angular tolerance >±60° is needed.
QSE113	6-pin DIP package with integrated lens; 0.8 mA I_ca; ±30° narrower angle; 20 μs rise time.	Better optical gain and directionality but higher cost and larger footprint; suited for precision position sensing over short gaps.	Choose QSE113 where higher sensitivity and tighter beam control justify added size and cost in critical end-stop applications.

Compared with TEPT5600 and QSE113, the VEMT3705-GS08 offers the optimal balance of SMT compatibility, speed, and angular control for high-volume photo interrupter and encoder designs - delivering 0.6 mA output and ±60° FOV in a 3.5 × 2.8 mm PLCC-2 footprint.

Availability

VEMT3705-GS08 is available at Aetrix Electronics and suitable for photo interrupters, miniature switches, and position sensors requiring stable component supply, consistent PLCC-2 tape-and-reel delivery (1500 pcs/reel), and long-term industrial lifecycle support.

Supply support for VEMT3705-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 devices, with emphasis on reliability, precision, and application-specific optimization.

The VEMT3705-GS08 belongs to Vishay's optoelectronics phototransistor product line, engineered for high-speed, ambient-stable optical detection in industrial automation, consumer controls, and motion feedback systems.

FAQ

What is the maximum collector-emitter voltage rating for the VEMT3705-GS08?

The VEMT3705-GS08 has a maximum collector-emitter voltage (V_CEO) rating of 20 V, as specified in the Absolute Maximum Ratings table. This value defines the upper limit of DC or peak pulse voltage that can be applied across the collector and emitter terminals without risking device breakdown. Exceeding 20 V may cause irreversible damage to the VEMT3705-GS08 junction.

Does the VEMT3705-GS08 require an external bias resistor?

Yes, the VEMT3705-GS08 requires an external collector pull-up resistor to convert photocurrent into a measurable voltage swing. Typical designs use 1–10 kΩ resistors between V_CC and the collector pin, with emitter grounded. The resistor value affects response speed and output voltage level - lower values improve speed but reduce signal amplitude. The VEMT3705-GS08 itself contains no internal bias circuitry.

What is the spectral response range of the VEMT3705-GS08?

The VEMT3705-GS08 exhibits spectral sensitivity from 480 nm to 1050 nm (λ_0.1), with peak response at 950 nm. This range covers visible blue light through near-infrared, making it compatible with standard GaAs IR emitters such as the VSML3710. Its relative spectral sensitivity curve (Fig. 8) confirms strong responsivity across the 850–950 nm band commonly used in industrial optointerrupters.

Is the VEMT3705-GS08 RoHS-compliant and lead-free?

Yes, the VEMT3705-GS08 is lead (Pb)-free and compliant with RoHS Directive 2011/65/EU. It supports lead-free reflow soldering per J-STD-020, with a peak temperature of 260 °C. The device is packaged in moisture barrier bags (MBB) with desiccant and carries MSL 3 classification (168 h floor life at <30 °C / <60 % RH), as documented in the official Vishay datasheet 80490.

How is the collector terminal identified on the VEMT3705-GS08 PLCC-2 package?

The collector terminal of the VEMT3705-GS08 is identified by a physical notch on the PLCC-2 package body - explicitly stated in the "Features" section of the datasheet. When viewing the top marking side with the notch oriented left, the left-hand lead is the collector and the right-hand lead is the emitter. This marking convention is critical for correct orientation during automated placement and functional circuit operation.

VEMT3705-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:: -

VEMT3705-GS08 FAQ

1.How can I place an order for VEMT3705-GS08 through Aetrix?

Please submit a Request for Quotation (RFQ) for VEMT3705-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 VEMT3705-GS08 reliable?

The price and inventory of VEMT3705-GS08 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for VEMT3705-GS08 is usually 5 days.

3.What payment methods are accepted for VEMT3705-GS08?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for VEMT3705-GS08 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for VEMT3705-GS08?

VEMT3705-GS08 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your VEMT3705-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 VEMT3705-GS08?

For technical support, including VEMT3705-GS08 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your VEMT3705-GS08 requirements.

6.How does Aetrix verify that VEMT3705-GS08 is sourced from the original manufacturer or authorized distributors?

All VEMT3705-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 VEMT3705-GS08 meets industry standards.

7.What is the process for return or replacement of VEMT3705-GS08?

All VEMT3705-GS08 units undergo pre-shipment inspection (PSI). If there is an issue with VEMT3705-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 VEMT3705-GS08 part is unused and in its original packaging.

Return procedure for VEMT3705-GS08:

1.Submit a request within 90 days.

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

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