## TSOP315 Series: Infrared Receiver Modules The **TSOP315** series is a miniaturized receiver for infrared (IR) remote control systems. It integrates a PIN diode and a preamplifier into a single lead frame, encapsulated in an epoxy package that acts as an IR filter. --- ### 1. Key Internal Components The TSOP315 is more than just a phototransistor; it is an integrated circuit (IC) containing several functional blocks: | Component | Function | | :--- | :--- | | **PIN Photodiode** | Converts incoming IR light into a low-level electrical signal. | | **Preamplifier** | Amplifies the weak electrical signal from the photodiode. | | **Automatic Gain Control (AGC)** | Adjusts sensitivity to compensate for ambient light noise and varying distances. | | **Band Pass Filter** | Blocks all frequencies except the specific carrier frequency (e.g., 38kHz). | | **Demodulator** | Extracts the digital data bits by removing the carrier wave. | --- ### 2. Technical Specifications The TSOP315 series typically operates under the following parameters: * **Supply Voltage ($V_S$):** 2.5 V to 5.5 V (making it compatible with 3.3V and 5V logic). * **Supply Current ($I_S$):** ~0.35 mA (very low power consumption). * **Transmission Distance:** Up to 45 meters. * **Carrier Frequency:** Typically 30kHz, 33kHz, 36kHz, 38kHz, 40kHz, or 56kHz (indicated by the last two digits, e.g., TSOP315**38**). --- ### 3. Pin Configuration The module generally has three pins. Looking at the front (the side with the sensor lens): | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **OUT** | Data Output (Active Low) | | 2 | **GND** | Ground | | 3 | **$V_S$** | Supply Voltage | --- ### 4. Application Circuit To ensure stable operation, a simple RC filter is recommended at the supply voltage pin to reduce noise. ```c +5V / +3.3V | [R1: 100 Ohm] | +-------+------- (Vs Pin) | | [C1: 4.7uF]| [TSOP315] | | GND GND ``` --- ### 5. Key Features * **Active Low Output:** The output pin stays HIGH when no signal is detected and drops to LOW when it receives a valid IR burst. * **Immunity to Ambient Light:** The internal filter and AGC make it highly resistant to sunlight and fluorescent lamp interference. * **Logic Compatibility:** Output can be directly connected to a Microcontroller (TTL/CMOS level). ---