The **TSOP323..** series (where the last two digits represent the carrier frequency) is a family of miniaturized IR receiver modules designed for infrared remote control systems. These components integrate a photopinhole, a preamplifier, and a demodulator into a single package. --- ### 1. Key Internal Components The TSOP323 series is more than just a photodiode; it is an Integrated Circuit (IC). Its internal structure consists of: | Component | Function | | :--- | :--- | | **Photodiode** | Converts infrared light signals into electrical current. | | **Band Pass Filter** | Filters out noise and only allows specific carrier frequencies (e.g., 38kHz). | | **Preamplifier** | Boosts the weak signal from the photodiode. | | **Demodulator** | Strips the carrier frequency to output the original data signal. | | **Control Circuit** | Includes Automatic Gain Control (AGC) to handle different lighting conditions. | --- ### 2. Technical Specifications The "323" series is specifically optimized for high immunity against ambient light and spurious pulses. * **Operating Voltage:** 2.5 V to 5.5 V. * **Supply Current:** Very low (typically 0.7 mA). * **Transmission Distance:** Up to 45 meters. * **Carrier Frequency:** Common variants include 30kHz, 33kHz, 36kHz, **38kHz (most common)**, 40kHz, and 56kHz. * **Output:** Active Low (the output drops to 0V when an IR signal is detected). --- ### 3. Pinout Configuration The TSOP323 modules typically use a 3-pin arrangement. Looking at the front (the bulbous side): | Pin Number | Name | Description | | :---: | :--- | :--- | | 1 | **OUT** | Data Output (Connects to Microcontroller) | | 2 | **GND** | Ground | | 3 | **Vs** | Power Supply (2.5V - 5.5V) | --- ### 4. Basic Wiring Diagram To ensure stable operation, a simple RC filter is recommended to suppress power supply noise. ```text +5V Supply | [R1: 100 Ohm] | +-------+-----------( Pin 3: Vs ) | | [C1: 4.7uF] | ( TSOP323.. ) | | GND GND-----------( Pin 2: GND ) ( Pin 1: OUT )------> MCU Input ``` --- ### 5. Why use TSOP323 over a standard IR Photodiode? * **Noise Rejection:** It ignores sunlight, CFL lamps, and LCD backlight noise. * **Simplicity:** It outputs a clean digital signal that a microcontroller (like Arduino) can read directly without complex analog processing. * **AGC 3 Version:** The "323" specifically uses the **AGC3** algorithm, which is ideal for suppressing almost all noise sources, making it very reliable for long-distance communication. ---