The TSOP1738 IR receiver is a widely used solution for detecting infrared remote-control signals in consumer and embedded electronics. This article will discuss the TSOP1738 IR receiver’s working principles, specifications, features, application circuits, alternatives, comparisons, and safe operation guidelines in detail.

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TSOP1738 IR Receiver Basic

The Vishay TSOP1738 is an infrared (IR) receiver module. It is designed for reliable remote-control signal detection. It is optimized for a 38 kHz carrier frequency, which is commonly used in TV, audio, and consumer electronics remotes. The device integrates a photodiode, automatic gain control, band-pass filter, and demodulator into a single compact package, making it easy to use in electronic designs.

The TSOP1738 outputs a clean digital signal that goes active low when it detects valid IR commands. Its internal filtering helps reject noise from ambient light, ensuring stable performance indoors. With low power consumption and direct compatibility with microcontrollers, it is widely used in Arduino projects, home automation, and IR-based control systems.

If you are interested in purchasing the TSOP1738, feel free to contact us for pricing and availability.

TSOP1738 IR Receiver CAD Models

TSOP1738 IR Receiver Pinout Details

Alternatives & Equivalent Model

• TSOP1736

• TSOP1740

• TSOP1838

• TSOP2238

• TSOP2438

• TSOP31238

• TSOP38238

• TSOP38438

TSOP1738 IR Receiver Block Diagram

The block diagram of the TSOP1738 IR receiver shows how an incoming infrared signal is processed and converted into a clean digital output. The process starts at the PIN photodiode, which detects infrared light from a remote control and converts it into a small electrical signal. This signal is very weak and may include noise from ambient light.

Next, the signal passes through the AGC (Automatic Gain Control) stage. AGC automatically adjusts the signal strength so the receiver can work reliably at different distances and under varying light conditions. The adjusted signal then enters the band-pass filter, which allows only signals near the target carrier frequency (38 kHz) to pass while blocking unwanted noise and interference.

The filtered signal is sent to the demodulator, which removes the 38 kHz carrier and recovers the original data pulses. Finally, the output transistor stage produces a digital output signal at the OUT pin, pulled up internally through a resistor to the supply voltage. This output can be read directly by a microcontroller or logic circuit.

TSOP1738 IR Receiver Specifications

TSOP1738 IR Receiver Features

• 38 kHz carrier frequency optimized for standard IR remote controls

• Built-in photodiode, preamplifier, and signal processing circuit

• Automatic Gain Control (AGC) for stable operation under different light conditions

• Integrated band-pass filter to reject ambient light and electrical noise

• Demodulated digital output suitable for microcontrollers and logic circuits

• Active-low output signal for easy interfacing

• High sensitivity with long transmission range (up to ~35 m)

• Wide viewing angle (approximately 45°)

• Low power consumption for battery-powered devices

• Operates from a 5 V supply range (4.5 V to 5.5 V)

• Good immunity to fluorescent lamps and sunlight interference

• Compact 3-pin package for easy PCB mounting

TSOP1738 Application Circuit

The application circuit shows how the TSOP1738 IR receiver is connected for reliable operation with a microcontroller. On the left side, an infrared LED (such as TSAL62) represents the IR transmitter, which sends a 38 kHz modulated signal toward the TSOP1738. The receiver detects this infrared light through its internal photodiode.

The TSOP1738 is powered through pin 2 (V_S) using a +5 V supply. A 330 Ω series resistor and a 4.7 µF capacitor are placed close to the device to reduce supply noise and voltage spikes. This filtering is important because the TSOP1738 is sensitive to power fluctuations, and clean power ensures stable signal detection.

Pin 3 provides the demodulated digital output, which connects directly to a microcontroller input. The optional pull-up resistor (>10 kΩ) ensures a defined logic level if required by the controller. When a valid IR signal is received, the output goes low in pulses that match the transmitted data. Pin 1 is connected to ground, completing the circuit. This setup allows the TSOP1738 to reliably receive and decode IR remote-control signals for digital systems.