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

Vishay Semiconductor Opto Division VEMT3700-GS18

Name: VEMT3700-GS18
Brand: Vishay Semiconductor Opto Division
SKU: VEMT3700-GS18
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: VEMT3700-GS18

Manufacturer:: Vishay Semiconductor Opto Division

Category:: Phototransistors

Package:: 2-SMD, J-Lead

Datasheet:: VEMT3700-GS18.pdf

Description:: PHOTO TRANS. SMD PLCC2

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Product details

Overview

VEMT3700-GS18 from Vishay Semiconductors is a high-speed silicon NPN epitaxial planar phototransistor in a PLCC-2 surface-mount package, rated for 70 V_CEO, 0.5 mA collector light current at 950 nm, ±60° half-sensitivity angle, and 6 µs rise/fall time with 1 kΩ load. It operates from −40 °C to +100 °C and is used in photo interrupters and position sensors where visible-to-NIR detection with fast response is required.

For engineers reviewing the VEMT3700-GS18 datasheet, VEMT3700-GS18 pinout, VEMT3700-GS18 application, or VEMT3700-GS18 equivalent, key selection criteria include radiant sensitivity (450–1080 nm spectral range), thermal resistance (400 K/W), MSL 3 floor life (168 h), and compatibility with VSML3710 IR emitters in compact optical sensing designs.

Technical Context

The VEMT3700-GS18 functions as a light-controlled NPN switch with emitter-grounded configuration and collector output. Its epitaxial planar structure enables fast carrier transport, yielding 2 µs response under 100 Ω load and 180 kHz cutoff frequency-critical for encoder and counter timing accuracy.

It features a defined angular sensitivity profile (±60° half-power angle) and peak spectral response at 850 nm, optimized for pairing with standard 950 nm IR emitters. The PLCC-2 package includes a notch marking the collector terminal and supports lead-free reflow per J-STD-020.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	70 V - Maximum collector-emitter voltage before breakdown; defines safe operating voltage headroom in open-collector switching circuits.
I_ca	0.5 mA typical - Collector light current under 1 mW/cm² irradiance at 950 nm; sets minimum detectable signal level for reliable logic-level output.
ϕ	±60° - Half-sensitivity viewing angle; determines mechanical alignment tolerance in slotted optocoupler or reflective sensor assemblies.
t_r/t_f	6 µs (1 kΩ), 2 µs (100 Ω) - Rise/fall times define maximum pulse repetition rate support; critical for >100 kHz encoder line counts.
λ_0.1	450–1080 nm - Spectral bandwidth enabling operation under ambient visible light or dedicated NIR illumination without filtering.
R_thJA	400 K/W - Junction-to-ambient thermal resistance on 4 mm × 4 mm PCB pad; informs derating requirements above 25 °C ambient.
V_CEsat	0.3 V max - Saturation voltage at I_C = 0.1 mA; ensures low power loss and clean TTL/CMOS-compatible low-state output.

Pinout & Package

Package: PLCC-2 (Plastic Leaded Chip Carrier, 2-terminal), dimensions 3.5 mm × 2.8 mm × 1.75 mm, notch-marked collector lead, surface-mount compatible with lead-free reflow.

Pin/Terminal	Circuit Role	Design Meaning
Collector	Output node, NPN drain	Marked by package notch; connects to pull-up resistor or logic input; carries photogenerated current to external load.
Emitter	Reference node, NPN source	Internally grounded in standard configuration; provides return path for photocurrent; must be tied to system ground for proper biasing.

Key Features

Feature	Design Value
High radiant sensitivity	0.5 mA output at 1 mW/cm² irradiance enables low-power emitter drive and reduced EMI in battery-operated sensors.
Fast response time	2 µs with 100 Ω load supports real-time position feedback in motor commutation and high-speed counting applications.
Visible/NIR spectral range	450–1080 nm coverage allows use with LED, incandescent, or IR sources without optical filtering in multi-source environments.
MSL 3 moisture sensitivity	168 h floor life at ≤30 °C / ≤60 % RH permits standard SMT handling without baking unless exposed beyond limit.
PLCC-2 mechanical compatibility	Matched footprint and optical axis alignment with VSML3710 emitter simplifies dual-component optical module layout and assembly.

Applications

Photo Interrupters	Miniature Switches
Use Scenario: Slotted optocoupler detecting object presence/absence in vending machines or printer paper-path monitoring. IC Role / Device Role / Timing Role: Light-controlled switch providing digital ON/OFF output synchronized to mechanical motion. Use Value: ±60° angular tolerance accommodates minor misalignment during assembly; 6 µs response ensures accurate edge detection at conveyor speeds up to 2 m/s.	Use Scenario: Non-contact tactile feedback in medical device control panels or industrial HMI buttons. IC Role / Device Role / Timing Role: Reflective-mode proximity detector triggering microcontroller GPIO interrupts. Use Value: 850 nm peak sensitivity matches common IR LEDs; 0.3 V V_CEsat guarantees noise-immune logic-low state under varying supply conditions.
Encoders	Position Sensors
Use Scenario: Incremental rotary encoder disk with alternating opaque/transparent segments on motor shafts. IC Role / Device Role / Timing Role: High-speed edge detector converting optical transitions into quadrature A/B pulses. Use Value: 180 kHz cutoff frequency supports >100 kpps line counts; 2 µs response prevents pulse distortion at 10,000 RPM.	Use Scenario: Linear position tracking in automated test equipment using calibrated reflective tape patterns. IC Role / Device Role / Timing Role: Analog light-current transducer feeding ADC or comparator for sub-millimeter resolution. Use Value: 0.25–0.5 mA I_ca range provides sufficient dynamic span for 10-bit ADC digitization without amplification.

Photo Interrupters

Miniature Switches

Use Scenario: Slotted optocoupler detecting object presence/absence in vending machines or printer paper-path monitoring.

IC Role / Device Role / Timing Role: Light-controlled switch providing digital ON/OFF output synchronized to mechanical motion.

Use Value: ±60° angular tolerance accommodates minor misalignment during assembly; 6 µs response ensures accurate edge detection at conveyor speeds up to 2 m/s.

Use Scenario: Non-contact tactile feedback in medical device control panels or industrial HMI buttons.

IC Role / Device Role / Timing Role: Reflective-mode proximity detector triggering microcontroller GPIO interrupts.

Use Value: 850 nm peak sensitivity matches common IR LEDs; 0.3 V V_CEsat guarantees noise-immune logic-low state under varying supply conditions.

Encoders

Position Sensors

Use Scenario: Incremental rotary encoder disk with alternating opaque/transparent segments on motor shafts.

IC Role / Device Role / Timing Role: High-speed edge detector converting optical transitions into quadrature A/B pulses.

Use Value: 180 kHz cutoff frequency supports >100 kpps line counts; 2 µs response prevents pulse distortion at 10,000 RPM.

Use Scenario: Linear position tracking in automated test equipment using calibrated reflective tape patterns.

IC Role / Device Role / Timing Role: Analog light-current transducer feeding ADC or comparator for sub-millimeter resolution.

Use Value: 0.25–0.5 mA I_ca range provides sufficient dynamic span for 10-bit ADC digitization without amplification.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
VEMT3705	Direct replacement per Vishay EOL notice; identical PLCC-2 package, ±60° angle, 450–1080 nm range, but improved I_ca = 0.6 mA typ. at 950 nm.	Same photo interrupter, encoder, and position sensor use cases; higher output current improves SNR in low-irradiance environments.	Select VEMT3705 for new designs requiring extended lifetime beyond February 2025 and marginally higher sensitivity.
TEFT4300	TO-92 through-hole package; 0.4 mA I_ca; ±35° angle; slower 12 µs response; same 70 V_CEO and −40 to +100 °C rating.	Suitable for prototyping or legacy through-hole boards; narrower viewing angle demands tighter mechanical alignment.	Choose TEFT4300 only when PLCC-2 SMT is unavailable or board redesign is impractical.

Compared with VEMT3705, the VEMT3700-GS18 offers identical form factor and optical performance but lower light current and end-of-life status; versus TEFT4300, it delivers superior speed, wider angular tolerance, and surface-mount compatibility-making it preferable for space-constrained, high-reliability optical sensing.

Availability

VEMT3700-GS18 is available at Aetrix Electronics and suitable for photo interrupters, encoders, miniature switches, and position sensors requiring stable component supply during the transition to VEMT3705 before its February 2025 end-of-life date.

Supply support for VEMT3700-GS18 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 manufacturer of discrete semiconductors and passive components, specializing in high-reliability optoelectronics, power MOSFETs, and precision resistors.

The VEMT series targets compact, high-speed optical sensing applications-including industrial automation, consumer electronics, and medical devices-where miniaturized PLCC-2 packaging and NIR responsiveness are essential.

FAQ

What is the maximum operating temperature for the VEMT3700-GS18?

The VEMT3700-GS18 has an operating temperature range of −40 °C to +100 °C, verified per its absolute maximum ratings table. This rating applies to ambient conditions with proper PCB thermal relief; junction temperature must not exceed 100 °C, requiring derating above 25 °C ambient based on its 400 K/W thermal resistance. The VEMT3700-GS18 maintains specified I_ca and response time across this full range.

Is the VEMT3700-GS18 RoHS-compliant and lead-free?

Yes, the VEMT3700-GS18 is lead (Pb)-free and compliant with RoHS Directive 2011/65/EU, as confirmed in its datasheet revision 1.7. It supports lead-free reflow soldering per J-STD-020, with peak temperature up to 260 °C. The device uses matte tin plating and meets Vishay's material categorization standards per document 99912.

What is the spectral response range of the VEMT3700-GS18?

The VEMT3700-GS18 has a spectral bandwidth of λ_0.1 = 450 nm to 1080 nm, meaning it responds to light intensities down to 10% of peak sensitivity across that range. Its peak sensitivity occurs at 850 nm, and it delivers 0.5 mA collector light current at 950 nm under 1 mW/cm² irradiance. This broad range supports both visible-light ambient sensing and dedicated NIR emitter applications.

How does the VEMT3700-GS18 differ from the VEMT3705 alternative?

The VEMT3705 is Vishay's designated direct replacement for the VEMT3700-GS18, sharing identical PLCC-2 packaging, ±60° half-sensitivity angle, and 450–1080 nm spectral range. Key differences include a higher typical collector light current (0.6 mA vs. 0.5 mA at 950 nm) and continued production beyond February 2025. The VEMT3700-GS18 remains functional but is end-of-life; no PCB changes are needed when migrating to VEMT3705.

What is the recommended load resistance for achieving 2 µs response time with the VEMT3700-GS18?

A 100 Ω load resistance is required to achieve the 2 µs rise/fall time specified in the VEMT3700-GS18 datasheet under V_S = 5 V, I_C = 1 mA, and λ = 950 nm conditions. Using a 1 kΩ load increases response time to 6 µs. Designers must balance speed against output voltage swing: 100 Ω yields ~0.05 V logic-low but maximizes bandwidth, while higher values improve signal amplitude at the cost of timing fidelity.

VEMT3700-GS18 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Semiconductor Opto Division

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Voltage - Collector Emitter Breakdown (Max):: -

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

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

Wavelength:: 850nm

Viewing Angle:: 120°

Power - Max:: 100 mW

Mounting Type:: Surface Mount

Orientation:: Top View

Operating Temperature:: -40°C ~ 100°C

Grade:: -

Qualification:: -

VEMT3700-GS18 FAQ

1.How can I place an order for VEMT3700-GS18 through Aetrix?

Please submit a Request for Quotation (RFQ) for VEMT3700-GS18 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 VEMT3700-GS18 reliable?

The price and inventory of VEMT3700-GS18 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for VEMT3700-GS18 is usually 5 days.

3.What payment methods are accepted for VEMT3700-GS18?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for VEMT3700-GS18 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for VEMT3700-GS18?

VEMT3700-GS18 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your VEMT3700-GS18 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 VEMT3700-GS18?

For technical support, including VEMT3700-GS18 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your VEMT3700-GS18 requirements.

6.How does Aetrix verify that VEMT3700-GS18 is sourced from the original manufacturer or authorized distributors?

All VEMT3700-GS18 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 VEMT3700-GS18 meets industry standards.

7.What is the process for return or replacement of VEMT3700-GS18?

All VEMT3700-GS18 units undergo pre-shipment inspection (PSI). If there is an issue with VEMT3700-GS18, 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 VEMT3700-GS18 part is unused and in its original packaging.

Return procedure for VEMT3700-GS18:

1.Submit a request within 90 days.

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

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