BPW34 - High-Speed PIN Photodiode

Overview

The BPW34 is a high-speed, high-sensitivity silicon PIN photodiode designed for applications requiring fast response times and excellent radiant sensitivity. Housed in a miniature flat plastic package, this component offers optimal performance for visible and near-infrared light detection. Its construction features a large radiant sensitive area combined with a wide angle of half sensitivity, making it suitable for diverse optical sensing applications.

This photodiode operates on the principle of the internal photoelectric effect, where incident light generates electron-hole pairs in the depletion region of the PIN structure. The BPW34's design emphasizes rapid response characteristics while maintaining high sensitivity across a broad spectral range.

Key Features

• Large radiant sensitive area: 7.5 mm² active detection surface
• Wide acceptance angle: ±65° angle of half sensitivity
• High photosensitivity: Excellent response across visible and near-IR spectrum
• Fast response time: Optimized for high-speed applications
• Small junction capacitance: Enables better high-frequency performance
• Plastic package: Miniature flat package (2.65mm x 4.6mm x 2.4mm)
• Spectral range: 400nm to 1100nm with peak sensitivity at 850nm

Applications

The BPW34 finds use in numerous applications requiring precise light detection and fast response:

Optical Communication Systems

• Fiber optic receivers
• Optical data transmission
• Infrared remote control systems

Industrial Sensing

• Object detection
• Position sensing
• Barcode scanners
• Industrial automation

Consumer Electronics

• Ambient light sensors
• Proximity detection
• Display brightness control

Medical Equipment

• Pulse oximetry
• Optical diagnostic equipment

Electrical Characteristics

(Typical values at T_A = 25°C unless otherwise specified)

Dark Characteristics

• Dark current (I_D): 2nA max at V_R = 10V
• Breakdown voltage (V_BR): 60V min

Photovoltaic Mode

• Open circuit voltage (V_OC): 350mV at E_e = 1mW/cm², λ = 950nm
• Short circuit current (I_SC): 50µA at E_e = 1mW/cm², λ = 950nm

Photoconductive Mode

• Junction capacitance (C_j): 72pF at V_R = 0V, f = 1MHz
• Rise time (t_r): 100ns at V_R = 10V, R_L = 1kΩ
• Fall time (t_f): 100ns at V_R = 10V, R_L = 1kΩ

Spectral Characteristics

• Peak sensitivity wavelength: 850nm
• Spectral range: 400nm to 1100nm
• Radiant sensitivity (S_e): 0.55A/W at λ = 850nm

Package Information

Mechanical Specifications

• Package type: Miniature flat plastic
• Dimensions: 4.6mm x 2.65mm x 2.4mm (L x W x H)
• Active area: 2.65mm x 2.65mm (7.5mm²)
• Lead material: Tin-plated copper alloy
• Weight: Approximately 0.05g

Pin Configuration

• Anode: Connected to case (marked side)
• Cathode: Non-marked side

Mounting Considerations

The BPW34 should be mounted with consideration for its optical requirements:

• Maintain clean optical path to active area
• Avoid mechanical stress on leads
• Consider environmental sealing if used in harsh conditions
• For optimal performance, minimize stray light interference

Optical Characteristics

Angular Sensitivity

The BPW34 features a wide acceptance angle with half-sensitivity at ±65° from normal incidence. This characteristic makes it suitable for applications where light may arrive from varying angles.

Linearity

The photocurrent output maintains excellent linearity with irradiance over several decades of light intensity, making it suitable for precise light measurement applications.

Reliability and Environmental Specifications

Operating Conditions

• Temperature range: -40°C to +85°C
• Storage temperature: -40°C to +100°C
• Humidity: Up to 85% relative humidity (non-condensing)

Soldering Information

• Wave soldering: 260°C max for 10 seconds
• Hand soldering: 350°C max for 3 seconds
• Reflow soldering: Follow standard IR reflow profile for plastic packages

Performance Considerations

Reverse Bias Operation

When operated in photoconductive mode with reverse bias, the BPW34 exhibits:

• Reduced junction capacitance for faster response
• Increased linearity range
• Improved signal-to-noise ratio

Temperature Effects

The dark current approximately doubles for every 10°C increase in temperature. For precision applications, temperature compensation may be required.

Design Guidelines

Circuit Configuration

For optimal performance:

• Use low-noise amplifier for signal conditioning
• Minimize parasitic capacitance in layout
• Consider transimpedance amplifier configuration for current-to-voltage conversion
• Implement proper shielding for noise-sensitive applications

Optical Considerations

• Match optical filters to desired spectral range
• Consider lensing for directional sensitivity
• Account for package window transmission characteristics

Comparison with Similar Devices

The BPW34 offers distinct advantages compared to other photodiodes: