PD204-6B/L3 Phototransistor Datasheet - 3mm Package - Peak Sensitivity 940nm - Technical Documentation

1. Product Overview

PD204-6B/L3 is a high-speed, high-sensitivity silicon PIN photodiode housed in a standard 3mm plastic package. Its spectral characteristics are matched to visible and infrared emitting diodes, with peak sensitivity optimized at a wavelength of 940nm. It is suitable for various sensing applications requiring fast response and reliable performance.

Key advantages of this component include its fast response time, high photosensitivity, and low junction capacitance, which together ensure efficient signal detection. This product complies with RoHS and EU REACH regulations and is manufactured using a lead-free (Pb-free) process.

2. Detailed Technical Parameters

2.1 Absolute Maximum Ratings

This device is designed to operate reliably within specified environmental and electrical limits. Exceeding these ratings may cause permanent damage.

• Reverse Voltage (VR):32 V - The maximum reverse bias voltage that can be applied across the photodiode.
• Operating Temperature (Topr):-25°C to +85°C - The ambient temperature range within which the device operates normally.
• Storage temperature (Tstg):-40°C to +100°C - The safe temperature range for storing the device when it is not powered.
• Soldering temperature (Tsol):According to the standard reflow profile, the peak temperature is 260°C, with a duration not exceeding 5 seconds.
• Pc (Power Consumption):150 mW at a free-air temperature of 25°C or below.

2.2 Electro-Optical Characteristics

These parameters define the core performance of the phototransistor under standard test conditions (Ta=25°C).

• Spectral Bandwidth (λ0.5):760 nm to 1100 nm. This defines the wavelength range over which the device maintains at least half of its peak sensitivity.
• Peak Sensitivity Wavelength (λP):940 nm (typical). The device is most sensitive to this infrared wavelength.
• Open-circuit voltage (VOC):Under the conditions of 940nm wavelength and an irradiance (Ee) of 1 mW/cm², the typical value is 0.42 V.
• Short-circuit current (ISC):Under the same test conditions (Ee=1mW/cm², λp=940nm), the typical value is 4.3 μA.
• Reverse photocurrent (IL):Under the conditions of VR=5V, Ee=1mW/cm², λp=940nm, the minimum value is 3.9 μA, and the typical value is 6 μA. This is the photocurrent generated when the diode is reverse-biased and illuminated.
• Reverse dark current (ID):Maximum value is 10 nA under conditions of VR=10V, complete darkness (Ee=0mW/cm²). This is the tiny leakage current that flows even when there is no light.
• Reverse Breakdown Voltage (VBR):Minimum value measured is 32 V when reverse current (IR) is 100μA in darkness.
• Total Capacitance (Ct):Under the conditions of VR=5V and frequency 1MHz, the typical value is 10 pF. Lower capacitance enables faster switching speeds.
• Rise/Fall Time (tr/tf):Under the conditions of VR=10V and a load resistance (RL) of 100Ω, the typical value is 10 ns / 10 ns, indicating an extremely fast response speed, suitable for pulsed light detection.
• Viewing Angle (2θ1/2):45° (typical value). This defines the angular field of view over which the device maintains sensitivity.

In related applications, the luminous intensity tolerance is ±10%, the dominant wavelength tolerance is ±1nm, and the forward voltage tolerance is ±0.1V.

3. Performance Curve Analysis

The datasheet provides multiple characteristic curves to illustrate the device's behavior under different conditions. These curves are crucial for design engineers to predict performance in real-world application scenarios.

3.1 Relationship Between Power Consumption and Ambient Temperature

The curve shows that when the ambient temperature exceeds 25°C, the maximum allowable power consumption decreases accordingly. Designers must derate the processing capability accordingly to ensure long-term reliability.

3.2 Spectral Sensitivity

The spectral response curve confirms the device's peak sensitivity at 940nm and its effective range from approximately 760nm to 1100nm. It highlights the device's suitability for applications utilizing common infrared LEDs.

3.3 Relationship Between Reverse Dark Current and Ambient Temperature

Dark current increases exponentially with temperature. For applications operating in high-temperature environments, this curve is crucial because higher dark current increases noise and may affect the signal-to-noise ratio under low-light conditions.

3.4 Relationship Between Reverse Photocurrent and Irradiance (Ee)

This graph illustrates the linear relationship between the generated photocurrent (IL) and the incident light intensity (irradiance) within the specified range. It confirms the predictable and linear photometric response of the device.

3.5 Relationship between Terminal Capacitance and Reverse Voltage

The junction capacitance (Ct) decreases with increasing reverse bias voltage. For high-speed applications, lower capacitance is desirable, and this curve aids in selecting the optimal operating bias point.

3.6 Relationship Between Response Time and Load Resistance

This curve shows how the rise and fall times (tr/tf) are affected by the value of the external load resistor (RL). Using a smaller load resistor enables faster response, but this comes at the expense of signal amplitude.

4. Mechanical and Packaging Information

4.1 Package Dimensions

The device uses a standard 3mm radial lead package. The dimension drawing specifies the body diameter, lead pitch, and lead dimensions. All unspecified tolerances are ±0.25mm. The lens color is black.

4.2 Polarity Identification

The cathode (negative terminal) is typically identified by a flat surface or a longer lead on the package body. Correct polarity must be observed during circuit assembly to ensure proper reverse bias operation.

5. Welding and Assembly Guide

This component is suitable for standard PCB assembly processes.

• Reflow soldering:Maximum soldering temperature is 260°C. The duration at or above this temperature must not exceed 5 seconds to prevent thermal damage to the plastic package and semiconductor chip.
• Manual Soldering:If manual soldering is required, a temperature-controlled soldering iron should be used, and contact time should be minimized (typically less than 3 seconds per lead).
• Cleaning:Use cleaning agents compatible with plastic packaging materials.
• Storage:Store in a dry, anti-static environment within the specified storage temperature range (-40°C to +100°C).

6. Packaging and Ordering Information

6.1 Packaging Quantity Specifications

Standard packaging is as follows: 200-1000 pieces per bag, 4 bags per box, 10 boxes per carton. This provides flexibility for prototype development and mass production.

6.2 Label Format Specifications

Product labels contain key information for traceability and identification:

• CPN:Customer Product Number
• P/N:Product Number (e.g., PD204-6B/L3)
• QTY:Packaging Quantity
• CAT, HUE, REF:Grading levels for luminous intensity, dominant wavelength, and forward voltage (if applicable).
• LOT No:Production lot number, used for traceability.
• X:Production month.

7. Application Recommendations

7.1 Typical Application Scenarios

PD204-6B/L3 is highly suitable for various photoelectric sensing applications, including:

• Automatic Door Sensors:Detects the interruption of infrared beams to trigger the door's open/close mechanism.
• Copying machines and printers:For paper detection, edge sensing, or toner level monitoring.
• Game consoles/arcade systems:For object detection, interactive control, or position sensing.
• General Infrared Sensing:Remote control receivers, proximity sensors, and industrial automation applications requiring fast, reliable detection of 940nm infrared light.

7.2 Design Considerations

• Bias Circuit:Operate the photodiode in reverse bias (photoconductive mode) for optimal speed and linearity. As specified, a typical reverse voltage is 5V to 10V.
• Load Resistor (RL):Select RL based on the trade-off between response speed (bandwidth) and output voltage swing. It is recommended to use a Transimpedance Amplifier (TIA) circuit to convert weak photocurrent into a usable voltage while maintaining high speed and low noise.
• Optical Considerations:Ensure proper alignment with the light source (typically a 940nm infrared LED). The field of view with a 45° viewing angle should be considered. Using an optical filter helps block unwanted ambient light, especially visible light.
• Noise Reduction:For sensitive applications, shield the device and its circuitry from electrical noise interference. Keep traces short, use bypass capacitors, and consider the impact of dark current at high temperatures.

8. Technical Comparison and Differentiation

Compared to standard photodiodes or phototransistors with slower response times, the PD204-6B/L3 offers significant advantages:

• High Speed:With a rise/fall time of 10ns, it is much faster than many general-purpose phototransistors and can detect rapidly modulated signals.
• PIN Structure:The PIN photodiode structure provides a wider depletion region than standard PN photodiodes, resulting in lower junction capacitance (10pF) and higher speed.
• Optimized Spectrum:The peak sensitivity at 940nm precisely matches the output of common, low-cost infrared LEDs, maximizing system efficiency.
• Standard Package:The 3mm radial package is a common industry form factor, easy to integrate into existing designs and compatible with standard PCB footprints.

9. Frequently Asked Questions (Based on Technical Parameters)

9.1 What is the difference between operating in photovoltaic mode (zero bias) and photoconductive mode (reverse bias)?

In photovoltaic mode (V_R=0V), the photodiode generates a voltage (V_OC). This mode has zero dark current but slower response and poorer linearity. The PD204-6B/L3 specifications list VOC=0.42V. In photoconductive mode (with reverse bias applied, e.g., V_R=5V), an external voltage is applied. This reduces junction capacitance (enabling faster response, as indicated by the 10ns tr/tf), improves linearity, and allows for a larger active area, but introduces dark current (I_D). For the high-speed applications intended for this device, photoconductive mode is recommended.

9.2 Ta yaya ake canza wutar lantarki ta haske (I_L) zuwa wutar lantarki da za a iya aunawa?

Hanya mafi sauƙi ita ce haɗa resistor na kaya (R_L) a jere. Fitowar ƙarfin lantarki ita ce V_out = I_L * R_L. Duk da haka, yayin da R_L ke ƙaruwa, lokacin RC (wanda ke da alaƙa da ƙarfin lantarki na diode) zai ƙaru, wanda zai rage saurin amsawa (kamar yadda aka nuna a cikin jadawalin dangantakar lokacin amsawa da resistor na kaya). Don samun mafi kyawun aiki, musamman a cikin yanayin ƙaramin ƙarfin lantarki da buƙatar sauri, amplifier na jujjuyawar (TIA) shine da'irar da aka fi so. Yana ba da ƙarfin lantarki mai ƙarfi, ƙaramin juriya (V_out = -I_L * R_f), yayin da yake kiyaye diode na haske a cikin ƙasa ta ƙarya, yana rage tasirin ƙarfin lantarki.

9.3 Me aha nui ai te ia hiko pōuri, ā, pēhea te pānga o te pāmahana ki taua mea?

Dark current (I_D) is the noise current that flows in the absence of light. It sets the lower limit of detectable light. The datasheet specifies a maximum of 10nA at 25°C. This current approximately doubles for every 10°C increase in temperature. Therefore, in high-temperature environments or for extremely low-light detection, dark current can become a significant noise source and must be considered in circuit design (e.g., through temperature compensation or synchronous detection techniques).

9.4 Ka taea te whakamahi i te pūtātari mō ngā puna rama atu i te 940nm?

Yes, but sensitivity will be reduced. The spectral response curve shows it has significant sensitivity in the range of 760nm to 1100nm. For example, it will respond to an 850nm LED, but the generated photocurrent under the same light intensity will be lower than when using a 940nm light source. For precise design, always refer to the relative spectral sensitivity curve (if the full version is provided), or calculate the responsivity at the desired wavelength.

10. Practical Design Case Analysis

Design Case: Infrared Beam Break Sensor for Security Gate.

Objective:Create a reliable, fast sensor to detect when an object interrupts an invisible infrared beam, thereby triggering a security alarm.

Implementation:

1. Transmitter:A 940nm infrared LED is driven by a pulsed current (e.g., 20mA pulses at 38kHz) to provide immunity against ambient light interference and reduce average power consumption.
2. Receiver:PD204-6B/L3 is placed opposite the transmitter, aligned within its 45° field of view. It is reverse-biased at 5V through a load resistor.
3. Signal Conditioning:The small AC photocurrent signal from the photodiode (superimposed on the DC dark current) is fed into a high-gain bandpass amplifier tuned to 38kHz. This filters out DC ambient light and low-frequency noise.
4. Detection:Then, the amplified signal is rectified and compared with a threshold. When the beam is not blocked, a strong 38kHz signal is present, and the comparator output is high. When an object blocks the beam, the signal disappears, causing the comparator to switch to low and activate the alarm.

Why PD204-6B/L3 is suitable:Its 10ns fast response time easily handles 38kHz modulated signals. High sensitivity at 940nm ensures good signal-to-noise ratio from a matched infrared LED. Low capacitance allows the circuit to maintain a fast response even with necessary filtering components.

11. Working Principle

PIN photodiodes like the PD204-6B/L3 operate based on the principle of the internal photoelectric effect. The device structure consists of a wide, lightly doped intrinsic (I) semiconductor region sandwiched between P-type and N-type regions. When photons with energy greater than the semiconductor bandgap (e.g., infrared light at 940nm for silicon) strike the intrinsic region, they generate electron-hole pairs. When the diode is reverse-biased, the built-in electric field in the depletion region (extending across the intrinsic layer) sweeps these charge carriers toward their respective terminals, generating a photocurrent (I_L) proportional to the incident light intensity. The wide intrinsic region reduces capacitance and allows for efficient collection of carriers generated over a larger volume, thereby contributing to increased speed and sensitivity.

12. Industry Trends and Background

Photodetectors such as the PD204-6B/L3 are fundamental components in the growing fields of optoelectronics and sensing. Current trends driving the demand for such devices include:

• Automation and Industry 4.0:In manufacturing, non-contact sensors are increasingly used for position, presence, and quality control.
• Consumer Electronics:Integrated into devices for proximity sensing (e.g., turning off the smartphone screen during calls), ambient light sensing to control display brightness, and gesture recognition.
• Internet of Things (IoT):Low-power, reliable sensors for smart home devices, security systems, and environmental monitoring.
• Technological Advancements:The overall trend is toward higher integration (e.g., photodiodes with on-chip amplifiers), smaller packages (surface-mount devices), lower power consumption, and enhanced performance at specific wavelengths (such as for LiDAR, biomedical sensing, and optical communication applications). Devices like the PD204-6B/L3 represent mature, reliable, and cost-effective solutions that meet mainstream infrared sensing needs.

13. Disclaimer and Usage Instructions

Key usage guidelines derived from the datasheet disclaimer include:

1. Specifications are subject to change without notice. Always refer to the latest official datasheet for design.
2. Under normal storage conditions, the product conforms to its published specifications for 12 months from the date of shipment.
3. The characteristic curves show typical performance, not guaranteed minimum or maximum values. Appropriate design margins should be allowed.
4. Strictly adhere to the Absolute Maximum Ratings. Operation beyond these limits may cause immediate or latent damage. The manufacturer assumes no responsibility for damage resulting from misuse.
5. This information is proprietary. Reproduction without permission is prohibited.
6. This componentIs notNot designed or certified for safety-critical applications such as medical life support, automotive control, aviation, or military systems. For such applications, contact the manufacturer for specifically certified products.