PD70-01B/TR10 Silicon Planar PIN Photodiode Datasheet - 2.0x1.25x0.7mm - Reverse Voltage 32V - Peak Sensitivity 940nm - English Technical Document

1. Product Overview

The PD70-01B/TR10 is a silicon planar PIN photodiode designed for high-sensitivity light detection across a broad spectral range. Its core advantages stem from the PIN structure, which incorporates an intrinsic (I) region between the P-type and N-type semiconductor layers. This intrinsic region widens the depletion layer, resulting in several key performance benefits critical for optoelectronic applications.

Core Advantages & Target Market: The device offers high sensitivity and fast switching times due to the reduced junction capacitance and efficient carrier collection in the PIN structure. The low dark current ensures good signal-to-noise ratio. Combined with its compact size and integrated daylight filter (black lens), it is ideally suited for diverse applications including consumer electronics remote controls (TV, appliances), infrared sound transmission systems, copiers, elevator sensors, and various industrial measurement and control systems requiring reliable optical sensing.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage may occur. Operating the device continuously at these limits is not recommended.

• Reverse Voltage (V_R): 32V. This is the maximum voltage that can be applied in reverse bias across the photodiode terminals.
• Power Dissipation (P_d): 150 mW at 25°C. This limits the total electrical power the device can handle, primarily determined by the reverse leakage current and any photocurrent under high illumination.
• Temperature Ranges: Operating: -25°C to +85°C; Storage: -40°C to +85°C. The device is designed for a wide industrial temperature range.
• Soldering Temperature (T_sol): 260°C for a maximum of 5 seconds. This is critical for Pb-free reflow soldering processes.

2.2 Electro-Optical Characteristics (Ta=25°C)

These parameters define the device's performance under typical operating conditions.

• Spectral Bandwidth (λ_0.5): 730 nm to 1100 nm. This defines the range of wavelengths where the photodiode's responsivity is at least half of its peak value. It is sensitive from visible red into the near-infrared (NIR) spectrum.
• Peak Sensitivity Wavelength (λ_P): 940 nm (Typical). The device is optimized for maximum response in the common NIR region, aligning with the emission of many IR LEDs.
• Short-Circuit Current (I_SC): 35 μA (Typical) under an irradiance of 1 mW/cm² at 875 nm. This parameter is measured with zero bias voltage (photovoltaic mode).
• Reverse Light Current (I_L): 25 μA (Typical) at V_R=5V under the same 1 mW/cm², 875 nm condition. Operating in reverse bias (photoconductive mode) generally yields higher and faster response compared to photovoltaic mode.
• Reverse Dark Current (I_D): 5 nA (Typical), 30 nA (Max) at V_R=10V. This is the leakage current in complete darkness. A low dark current is essential for detecting weak light signals.
• Reverse Breakdown Voltage (V_BR): 170V (Typical), with a minimum of 32V. This is the voltage at which the reverse current increases sharply. Normal operating reverse voltage should be well below this value.

3. Performance Curve Analysis

The datasheet includes typical characteristic curves which are crucial for design.

• Spectral Sensitivity Curve: This graph shows the relative responsivity versus wavelength. It confirms the peak at ~940 nm and the defined bandwidth from 730 nm to 1100 nm. The integrated black lens acts as a visible light filter, attenuating sensitivity in the visible range to reduce noise from ambient light (daylight).
• Reverse Light Current vs. Irradiance (Ee): This curve illustrates the linear relationship between the generated photocurrent (I_L) and the incident light power density. The linearity is a key feature of PIN photodiodes, making them suitable for light measurement applications.

4. Mechanical and Package Information

4.1 Package Dimensions

The PD70-01B/TR10 comes in a very small surface-mount package. Key dimensions (in mm) include a body size of approximately 2.0 x 1.25, with a height of 0.7 mm. The cathode is typically identified by a marked corner or a notch on the package. Detailed dimensional drawings with tolerances of ±0.1mm are provided for PCB footprint design.

4.2 Polarity Identification

Clear polarity marking is essential for correct installation. The datasheet package diagram indicates the anode and cathode terminals. Incorrect polarity connection when applying reverse bias will forward-bias the diode, potentially causing high current flow and damage.

5. Soldering and Assembly Guidelines

Proper handling is critical for reliability.

5.1 Storage and Moisture Sensitivity

The device is moisture sensitive. Precautions include: storing in the original sealed bag at ≤30°C/90%RH; using within 1 year of shipment; after opening, storing at ≤30°C/70%RH and using within 168 hours (7 days). If exceeded, a baking treatment at 60±5°C for 24 hours is required before soldering.

5.2 Soldering Conditions

• Reflow Soldering: A Pb-free solder temperature profile is recommended, with a peak temperature of 260°C for up to 5 seconds. Reflow should not be performed more than two times.
• Hand Soldering: If necessary, use a soldering iron with temperature <350°C and power <25W. Contact time per terminal should be <3 seconds, with intervals >2 seconds between terminals to avoid thermal stress.
• Repairing: Not recommended after soldering. If unavoidable, a double-head soldering iron must be used to simultaneously heat both terminals during removal to prevent mechanical stress on the semiconductor die.

6. Packaging and Ordering Information

The standard packaging is a reel format containing 1000 pieces (1000PCS/Reel). The reel dimensions are specified for automated pick-and-place equipment handling. The label on the reel includes critical information such as Part Number (P/N), Lot Number (LOT No), quantity (QTY), and other traceability codes.

7. Application Notes and Design Considerations

7.1 Typical Application Circuits

The photodiode can be used in two primary modes:

1. Photovoltaic Mode (Zero Bias): The photodiode generates a voltage/current when illuminated, with no external bias applied. This mode offers very low dark current and noise but has slower response speed and lower linearity.
2. Photoconductive Mode (Reverse Bias): An external reverse voltage is applied (e.g., 5V as in the I_L test condition). This mode widens the depletion region further, reducing junction capacitance and resulting in much faster switching times and higher linearity over a wider light intensity range. This is the preferred mode for high-speed detection like IR remote control receivers.

7.2 Critical Design Precautions

• Current Limiting/Protection: When operating in a circuit, a series resistor MUST be used to limit current. As stated in the precautions, "slight voltage shift will cause big current change (Burn out will happen)." This is because a photodiode under reverse bias, if exposed to very high light intensity or if forward-biased by mistake, can conduct excessive current.
• Circuit Board Layout: Minimize parasitic capacitance and inductance in the traces connecting the photodiode to the amplifier or comparator. This is vital for preserving high-speed performance.
• Ambient Light Rejection: The built-in black lens helps, but for best performance in ambient light, optical filtering (an additional IR-pass filter) and electrical filtering (synchronous detection) may be necessary.

8. Technical Comparison and Differentiation

The PD70-01B/TR10 differentiates itself through its combination of features in a compact SMD package:

• vs. Standard Photodiodes: The PIN structure offers lower capacitance and faster response than standard PN photodiodes.
• vs. Larger PIN Diodes: Its tiny 2.0x1.25mm footprint allows for high-density PCB designs where space is constrained.
• Integrated Filter: The inclusion of a daylight filter (black epoxy) simplifies design by reducing the need for an external filter to block visible light noise.
• Robust Ratings: A wide operating temperature range (-25°C to +85°C) and a high typical breakdown voltage (170V) provide design margin and reliability.

9. Frequently Asked Questions (FAQs)

Q: What is the purpose of the "daylight filter"?
A: The black lens material attenuates light in the visible spectrum (roughly 400-700 nm) while allowing near-infrared light (700-1100 nm) to pass through. This reduces the interference from ambient indoor lighting (fluorescent, LED, incandescent) which contains visible light, improving the signal-to-noise ratio for IR-based systems.

Q: Should I use this in photovoltaic or photoconductive mode for an IR remote receiver?
A> For IR remote control applications which require fast pulse detection (typically 38-56 kHz carrier), the photoconductive mode (reverse biased) is mandatory. The reduced capacitance in this mode enables the device to respond to the high-frequency modulation.

Q: How do I calculate the value of the required series resistor?
A: The resistor limits the maximum current. If applying a reverse bias V_R, and the maximum expected photocurrent is I_max, a simple series resistor R can be placed. The voltage drop across it should not significantly reduce the bias on the diode. For example, with V_R = 5V and I_max ~ 50μA, a resistor of 10kΩ would drop only 0.5V, leaving 4.5V across the diode. The resistor also helps protect against accidental forward bias.

10. Operational Principle

A PIN photodiode operates on the principle of the internal photoelectric effect. Photons with energy greater than the semiconductor's bandgap are absorbed in the intrinsic region, creating electron-hole pairs. The strong electric field present in the reverse-biased depletion region (which is enlarged by the intrinsic layer) swiftly separates these carriers, causing them to drift to the respective terminals. This movement of charge constitutes a photocurrent that is proportional to the incident light intensity. The wide intrinsic region is key: it increases the volume for photon absorption (improving sensitivity) and reduces the junction capacitance (enabling faster speed).

11. Industry Trends

The demand for compact, high-speed, and sensitive photodetectors continues to grow. Trends influencing devices like the PD70-01B/TR10 include:

• Miniaturization: The push for smaller consumer electronics and IoT devices drives the need for ever-smaller optical sensors with maintained or improved performance.
• Increased Integration: While discrete photodiodes remain essential, there is a trend toward integrating the photodiode with a transimpedance amplifier (TIA) and other signal conditioning circuitry into a single package, simplifying design.
• Expansion of NIR Applications: Beyond traditional remote controls, NIR sensing is expanding into areas like proximity sensing, gesture recognition, spectral analysis, and biomedical monitoring, all requiring reliable photodetectors.
• Enhanced Reliability Standards: Compliance with environmental regulations (RoHS, REACH, Halogen-Free) and stringent automotive/industrial reliability grades is becoming standard for components used across various markets.