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HomeProductsSensors, TransducersOptical Sensors - PhototransistorsPT91-21B/TR10
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PT91-21B/TR10 - Everlight Electronics Co Ltd

Manufacturer Part Number
PT91-21B/TR10
Manufacturer
Everlight Electronics
Allelco Part Number
32D-PT91-21B/TR10
Warranty
1 Year Allelco Warranty - Find out more
Stock Status:
154,300 pcs available, New & Original
Parts Description
SENSOR PHOTO 940NM TOP VIEW 2SMD
Package
2-SMD, Z-Bend
Data sheet
-
RoHs Status
ROHS3 Compliant
Compare
Our certification
In stock: 154300
  • Unit Price: $0.034
  • Subtotal: $0.00

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Quantity Unit Price Ext. Price
10+ $0.034 $0.34
100+ $0.028 $2.80
300+ $0.024 $7.20
1000+ $0.021 $21.00
5000+ $0.019 $95.00
10000+ $0.018 $180.00
The above prices does not include taxes and freight rates, which will be calculated on the order pages.

Specifications

PT91-21B/TR10 Tech Specifications
Everlight Electronics Co Ltd - PT91-21B/TR10 technical specifications, attributes, parameters and parts with similar specifications to Everlight Electronics Co Ltd - PT91-21B/TR10

Product Attribute Attribute Value
Manufacturer Everlight Electronics
Wavelength 940nm
Voltage - Collector Emitter Breakdown (Max) 30 V
Viewing Angle -
Series -
Package / Case 2-SMD, Z-Bend
Package Tape & Reel (TR)
Product Attribute Attribute Value
Orientation Top View
Operating Temperature -25°C ~ 85°C (TA)
Mounting Type Surface Mount
Current - Dark (Id) (Max) 100 nA
Current - Collector (Ic) (Max) 20 mA
Base Product Number PT91-21

Environmental & Export Classifications

ATTRIBUTE DESCRIPTION
RoHs Status ROHS3 Compliant
Moisture Sensitivity Level (MSL) 3 (168 Hours)
ECCN EAR99
HTSUS 8541.49.7080

Frequently Asked Questions(FAQ)

How does the PT91-21B/TR10 compare to standard phototransistors in terms of dark current and collector current, and what implications do these values have for low-power infrared sensing applications?
The PT91-21B/TR10 exhibits a maximum dark current of 100 nA and a peak collector current of 20 mA at 940 nm wavelength, which is typical for near-infrared phototransistors designed for ambient-insensitive detection. Compared to general-purpose phototransistors with higher dark currents (often in the microampere range), this device offers superior signal-to-noise performance in low-light conditions due to its tighter dark current specification. The 20 mA maximum collector current provides sufficient drive capability for direct interfacing with common microcontroller input pins or simple comparator circuits without requiring additional buffering. This balance makes it suitable for battery-powered remote control systems and proximity sensors where power efficiency and reliable detection are critical.
What design considerations should be taken into account when integrating the PT91-21B/TR10 into a surface-mount PCB layout to ensure optimal optical coupling and thermal reliability?
The PT91-21B/TR10 uses a 2-SMD Z-bend package with top-view orientation, which allows direct alignment with infrared emitters in compact assemblies. For effective optical coupling, the emitter and detector should be positioned within the viewing angle of the phototransistor—typically aligned coaxially with minimal spacing—to maximize responsivity. The Z-bend leads facilitate placement on both sides of the component footprint, enabling efficient use of board real estate. Thermal management is generally not a concern due to the small form factor, but soldering must adhere to the MSL 3 (168-hour floor life) requirement; components should be stored in moisture barrier bags and baked if exposure exceeds 168 hours. Reflow profiles should respect the operating temperature range of -25°C to 85°C to avoid degradation of internal bonds.
Can the PT91-21B/TR10 be used reliably in ambient light environments, and how does its 940 nm wavelength selection impact interference from common indoor lighting sources?
Yes, the PT91-21B/TR10 is well-suited for operation in ambient light environments due to its narrow spectral response centered at 940 nm. Most visible light sources—such as incandescent bulbs, fluorescent lamps, and daylight—emit significantly less energy at this wavelength compared to their peak emission bands. This reduces false triggering caused by background illumination. In contrast, devices responsive to longer wavelengths like 850 nm may experience greater interference from sunlight or LED room lighting. The combination of low dark current (100 nA max) and high responsivity at 940 nm enables stable performance even under moderate ambient IR exposure, making it ideal for applications like object detection behind glass or in outdoor environments during daytime.
How does the voltage rating of 30 V for the collector-emitter breakdown affect circuit protection design when using the PT91-21B/TR10 in high-impedance feedback configurations?
With a maximum collector-emitter breakdown voltage of 30 V, the PT91-21B/TR10 can safely operate in circuits powered up to 24 V without requiring external clamping diodes, simplifying design in industrial sensor nodes. However, in high-impedance feedback networks—such as transimpedance amplifiers—the phototransistor’s output is often connected across a large resistor (e.g., 1 MΩ). A transient voltage spike exceeding 30 V could permanently damage the device, even if the supply rail is lower. Therefore, designers should include series resistors or TVS diodes in such configurations to limit overvoltage stress. Additionally, the 20 mA maximum collector current imposes a practical upper bound on load resistance; for example, at 30 V, Ohm’s law suggests a minimum load resistance of 1.5 kΩ to stay within safe operating limits.
What are the key differences between the PT91-21B/TR10 and alternative phototransistors like those in the PT45 series regarding mounting type and electrical characteristics, and how might these influence PCB assembly choices?
Unlike leaded radial packages common in older phototransistor families, the PT91-21B/TR10 features a surface-mount 2-SMD Z-bend configuration, enabling automated pick-and-place assembly and higher density layouts. In comparison, many legacy parts require through-hole mounting, increasing manual labor and reducing scalability. Electrically, the PT91-21B/TR10 shares similar collector current (20 mA) and dark current (100 nA) specifications with other Everlight phototransistors, but its top-view orientation improves optical efficiency in space-constrained designs. The absence of a defined viewing angle means system-level optical modeling is necessary to ensure adequate emitter-detector alignment, whereas some competitors specify full-angle coverage for easier integration.
Is the PT91-21B/TR10 compatible with automatic optical inspection (AOI) systems during manufacturing, and what packaging feature supports this process?
Yes, the PT91-21B/TR10 is packaged in Tape & Reel (TR) format, which is fully compatible with standard pick-and-place machines used in SMT lines. The reel packaging ensures consistent feeding during high-speed assembly, minimizing placement errors. Additionally, the Z-bend lead geometry allows for precise fiducial alignment and visual inspection post-placement. Since the component lacks a transparent lens or color code, machine vision systems rely on footprint recognition and polarity marking (typically indicated by a dot or notch on the body) to verify correct orientation. This integration supports high-volume production environments where traceability and yield optimization are essential.
What role does the base product number PT91-21 play in component lifecycle management, and how does it relate to the variant PT91-21B/TR10?
The base product number PT91-21 serves as the core identifier across multiple variants, including different package types, wavelength tolerances, and packaging formats. The PT91-21B/TR10 specifically denotes a 940 nm version housed in a 2-SMD Z-bend package delivered on tape and reel. Using the base part number facilitates bulk procurement and simplifies inventory classification in MRP systems. Manufacturers and distributors maintain consistent electrical characteristics across variants to support design reuse, while minor changes—such as packaging or RoHS compliance updates—are reflected in suffixes like /TR10. This modular approach enhances supply chain flexibility without requiring complete redesigns.
How does the operating temperature range of -25°C to 85°C influence reliability testing and application suitability for automotive-grade versus commercial electronics using the PT91-21B/TR10?
While the PT91-21B/TR10 operates reliably from -25°C to 85°C (TA), this range aligns with commercial-grade standards rather than extended automotive (-40°C to +125°C) requirements. At elevated temperatures near 85°C, dark current may increase slightly due to carrier generation mechanisms, potentially reducing SNR in precision analog front-ends. Designers targeting harsh environments should derate the device accordingly or implement temperature compensation algorithms. Conversely, in consumer or industrial control systems within this range, no special qualification beyond standard datasheet parameters is needed. The MSL 3 designation also implies that long-term storage above 60°C could accelerate moisture ingress risk, necessitating controlled storage conditions per JEDEC guidelines.
Why might a designer choose the PT91-21B/TR10 over photodiodes for infrared presence detection, and what trade-offs emerge in speed and linearity?
The PT91-21B/TR10 offers higher gain than photodiodes, enabling simpler interface circuitry with minimal amplification for weak signals, which is advantageous in cost-sensitive applications like gesture recognition or object counting. However, this comes at the expense of bandwidth: phototransistors typically respond more slowly (nanosecond to microsecond scale) compared to photodiodes (picosecond to nanosecond), limiting use in high-speed modulation scenarios above several hundred kHz. For continuous-wave 940 nm systems operating below 100 kHz modulation frequency, the PT91-21B/TR10 provides sufficient response time with superior sensitivity. Linearity is also poorer due to internal current gain saturation, so analog output requires careful biasing to avoid clipping in variable-intensity environments.
What environmental certifications such as RoHS, ECCN, and HTSUS apply to the PT91-21B/TR10, and how do they affect global supply chain logistics?
The PT91-21B/TR10 complies with RoHS3 Directive (EU 2015/869), restricting hazardous substances like lead, mercury, and cadmium. Its ECCN classification is EAR99, indicating it is subject to U.S. Commerce Control List (CCL) Category 5 Part 2 but generally unrestricted for export under license exception ENC. The HTSUS code 8541.49.7080 places it under "Photoswitches, photovoltages, and photoemissive semiconductors" for customs valuation and tariff purposes. These classifications simplify import procedures in most markets but require documentation for shipments to countries with strict chemical regulations. Compliance ensures compatibility with green manufacturing initiatives and avoids potential penalties during customs clearance.

Parts with Similar Specifications

The three parts on the right have similar specifications to Everlight Electronics Co Ltd PT91-21B/TR10

Product Attribute PT91-21C/TR10 PT91-21B/TR7 PT91-21B/TR9 PT91-21C/TR7
Part Number PT91-21C/TR10 PT91-21B/TR7 PT91-21B/TR9 PT91-21C/TR7
Manufacturer Everlight Electronics Co Ltd Everlight Electronics Co Ltd Everlight Electronics Co Ltd Everlight Electronics Co Ltd
Orientation - - - -
Base Product Number - DAC34H84 MAX500 ADS62P42
Viewing Angle - - - -
Operating Temperature - -40°C ~ 85°C 0°C ~ 70°C -40°C ~ 85°C
Current - Collector (Ic) (Max) - - - -
Package - Tape & Reel (TR) Tube Tape & Reel (TR)
Current - Dark (Id) (Max) - - - -
Package / Case - 196-LFBGA 16-DIP (0.300', 7.62mm) 64-VFQFN Exposed Pad
Series - - - -
Voltage - Collector Emitter Breakdown (Max) - - - -
Mounting Type - Surface Mount Through Hole Surface Mount
Wavelength - - - -

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Customer Reviews

Evaluation: 10 Articles

  • Nath***rooks
    Jun 11, 2026

    Installed this power component in a converter board. Output remained stable under different load conditions and thermal performance was better than expected.

  • Dani***alkerTech
    Jun 1, 2026

    Product works, but setup took more effort than expected. Once configured the MCU ran reliably, although documentation support felt older compared with newer platforms. Fine for maintenance projects.

  • Yuki***aka88
    May 26, 2026

    信号通信プロジェクトでこのRS-485トランシーバーを使用しました。設置は簡単で、長距離ケーブルでも通信は安定していました。消費電力も、以前使用していたものより低くなっています。

  • Stev***aker
    May 20, 2026

    Solid diode for power rectification. Works well in switching circuits.

  • Bran***Lewis
    May 11, 2026

    Compact FPGA with good performance. Suitable for basic signal processing tasks.

  • Oliv***arris
    May 7, 2026

    Reliable I/O expander. Works well in embedded control applications.

  • Jess***Jones
    Apr 17, 2026

    It offers good value for the price, and the specifications match the description. I’ve been using it for two days with no issues, and I’ll definitely buy it again if I need it in the future.

  • Mich***Smith
    Apr 17, 2026

    Shipping was on time, the component pins are neatly aligned, and I tested 10 of them with a multimeter—all readings were within the specified range. Highly recommended.

  • Aman***arris
    Apr 3, 2026

    It was great—the entire process, from placing the order to receiving the package, went very smoothly. The components were consistent, the price was fair, and I had a very pleasant shopping experience.

  • Mike***nch
    Apr 3, 2026

    Better than expected! The resistance and capacitance readings were spot-on, and it passed the test on the first try. The service was reliable, and the packaging was thoughtful—I highly recommend it.

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Shipment

Delivery Time

In-stock items can be shipped within 24 hours. Some parts will be arranged for delivery within 1-2 days from the date all items arrive at our warehouse. And Allelco ships order once a day at about 17:00, except Sunday. Once the goods are shipped, the estimated delivery time depends on the shipping methods and Delivery destination. The table below shows are the logistic time for some common countries.

Delivery Cost

  1. Use your express account for shipment if you have one.
  2. Use our account for the shipment. Refer to the table below for the approximate charges.
(Different time frame / countries / package size has different price.)

Delivery Method

  1. Global Common Shipment by DHL / UPS / FedEx / TNT / EMS / SF we support.
  2. Others more shipping ways, please get in touch with your customer manager.

Common Countries Logistic Time Reference
Region Country Logistic Time(Day)
America United States 5
Brazil 7
Europe Germany 5
United Kingdom 4
Italy 5
Oceania Australia 6
New Zealand 5
Asia India 4
Japan 4
Middle East Israel 6
DHL & FedEx Shipment Charges Reference
Shipment charges(KG) Reference DHL(USD$)
0.00kg-1.00kg USD$30.00 - USD$60.00
1.00kg-2.00kg USD$40.00 - USD$80.00
2.00kg-3.00kg USD$50.00 - USD$100.00
Note:
The above table is for reference only. There may have some data bias for the uncontrollable factors.
Contact us if you have any questions.
  • QC (Quality Warranty)
  • Payment Support
  • Packaging
  • Certifications & Memberships

QC (Quality Warranty)

Allelco is committed to exceeding customer expectations through customer service excellence, order accuracy, and on-time delivery.
This is achieved through our commitment to the continual improvement of our processes, services, and products.


Strict quality inspection builds a solid foundation for electronic component quality.
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We eliminate defective components and ensure the stable operation of electronic devices through professional quality standards.
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Packaging

Electrostatic Discharge Protection and Handling

All electrostatic-sensitive components are handled in accordance with electrostatic discharge control procedures. The products are hermetically sealed in anti-static safe packaging to prevent electrostatic damage. Appropriate labeling is also applied for identification and traceability. This ensures product integrity during storage, handling and transportation.


ESD

Certifications & Memberships

Third-party certified, strict quality control. Our certification
  • ISO 9001: 2015
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  • ISO 14001: 2015
  • ISO 28000: 2007
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  • IPC
  • ESD
  • PSMA
PT91-21B/TR10 Image

PT91-21B/TR10

Everlight Electronics Co Ltd
32D-PT91-21B/TR10

Want a better price? Add to Cart and Submit RFQ now, we'll contact you immediately.

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