### Overview of the TSOP1140 Series The **TSOP1140** (often part of the TSOP11xx family) is a miniaturized receiver for infrared (IR) remote control systems. It combines a PIN diode and a preamplifier on a single lead frame, encapsulated in an epoxy package that acts as an IR filter. --- ### Key Technical Specifications | Parameter | Typical Value | | :--- | :--- | | **Supply Voltage (Vs)** | 2.7 V to 5.5 V | | **Carrier Frequency** | 40 kHz (for the 1140 model) | | **Supply Current** | 0.4 mA to 1.0 mA | | **Transmission Distance** | Up to 35 meters | | **Output Type** | Active Low (Open Collector) | | **Operating Temperature** | -25°C to +85°C | --- ### Internal Block Diagram Functions The internal circuitry consists of five main stages: 1. **PIN Photodiode:** Converts incoming IR light pulses into electrical signals. 2. **Preamplifier:** Boosts the weak signal from the photodiode. 3. **Automatic Gain Control (AGC):** Adjusts sensitivity to suppress noise from sunlight or fluorescent lamps. 4. **Band Pass Filter:** Specifically tuned to **40 kHz** to filter out IR noise at other frequencies. 5. **Demodulator & Output Driver:** Removes the 40 kHz carrier wave and outputs the data signal (envelope). --- ### Pinout Configuration The TSOP1140 typically features three pins. Looking at the front (the side with the lens): 1. **Pin 1 (OUT):** Data output; connects to a microcontroller. 2. **Pin 2 (GND):** Ground connection. 3. **Pin 3 (Vs):** Power supply (usually +5V). --- ### Typical Application Circuit To ensure stable operation, a simple RC filter is recommended for the power supply to block noise. ```text +5V Supply | [R1: 100 Ohm] | +-------+-----------+ | | | [C1] [TSOP] [MCU] 4.7uF 1: OUT ----> GPIO | 2: GND ----> GND GND 3: Vs <----+ ``` --- ### Important Usage Notes * **Carrier Frequency:** The "40" in TSOP1140 denotes the 40 kHz frequency. It will not work efficiently with 38 kHz transmitters. * **Active Low:** The output is "High" when no signal is detected and "Low" when a 40 kHz IR burst is received. * **Optical Filter:** The black epoxy case filters out visible light (wavelengths < 700nm) to prevent interference.