Vishay Semiconductor Opto Division TSOP77438TT

Overview

TSOP77438TT from Vishay Semiconductors is a surface-mount infrared (IR) receiver module optimized for long-burst remote control systems operating at 38 kHz carrier frequency, with AGC4 configuration for enhanced noise immunity against fluorescent lamps, LCD TVs, and Wi-Fi interference, and designed for direct interface to microcontrollers in consumer electronics remote receivers.

For engineers reviewing the TSOP77438TT datasheet, TSOP77438TT pinout, TSOP77438TT application, or TSOP77438TT equivalent, this device delivers verified NEC and Sharp code compatibility, ±50° horizontal/vertical directivity, and low 0.35 mA typical supply current at 3.3 V - critical for battery-powered IR receivers requiring robust ambient-light rejection and reliable burst-length discrimination.

Technical Context

The TSOP77438TT integrates a PIN photodiode, preamplifier, bandpass filter, demodulator, and AGC control circuit in a single Heimdall SMD package. Its AGC4 variant provides higher noise suppression than AGC2, enabling operation under strong ambient IR disturbances including high-modulation fluorescent lamp emissions (Fig. 15) and 2.4/5 GHz Wi-Fi signals.

It features a fixed 38 kHz center frequency with ±5% bandwidth (Δf_3dB = f₀/10), supports minimum burst lengths of 10 cycles, requires ≥10-cycle gap times, and automatically reduces sensitivity during disturbance to prevent spurious output pulses - distinguishing valid RC-5, NEC, Sharp, and Mitsubishi codes from noise based on frequency, burst envelope, and duty cycle.

Key Specifications

Pinout & Package

TSOP77438TT uses the Heimdall surface-mount package (6.8 mm × 3.0 mm × 3.2 mm) with gull-wing leads and integrated IR filter epoxy molding. Pin assignment is standardized across TSOP77x series.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar IR receiver applications.

Compared with TSOP77438TT, TSOP77238 trades noise immunity for broader legacy protocol support, while TSOP38238 retains identical functionality in a non-SMD form factor - making TSOP77438TT the optimal choice for new SMD designs prioritizing Wi-Fi/fluorescent resilience and space-constrained layouts.

Availability

TSOP77438TT is available at Aetrix Electronics and suitable for TV remote receivers, set-top box controls, audio system remotes, and smart home hub IR interfaces requiring stable component supply, consistent AGC4 performance, and long-burst protocol compliance.

Supply support for TSOP77438TT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Vishay Semiconductors is a global leader in discrete semiconductors and passive components, specializing in high-reliability optoelectronics, power management, and sensing solutions for industrial and consumer markets.

The TSOP77438TT belongs to Vishay's TSOP77x family of AGC-configurable IR receivers, engineered specifically for noise-immune remote control reception in modern living environments with dense RF and optical interference.

FAQ

What is the carrier frequency and AGC setting of TSOP77438TT?

The TSOP77438TT is configured for 38 kHz carrier frequency with AGC4 (high-gain automatic gain control), optimized for long-burst remote protocols like NEC and Sharp. This AGC level provides superior suppression of complex ambient IR noise - including high-modulation fluorescent lamp emissions and 2.4/5 GHz Wi-Fi interference - while maintaining full compatibility with standard 38 kHz remote signals. The AGC4 setting is factory-trimmed and not user-adjustable.

Does TSOP77438TT require an external pull-up resistor on the OUT pin?

Yes, TSOP77438TT features an open-collector active-low output, so an external pull-up resistor (typically 4.7 kΩ to VS) is required unless the connected microcontroller GPIO has a programmable internal pull-up enabled and rated for 5 mA sink capability. The datasheet specifies maximum output sink current as 5 mA, and output voltage low is guaranteed ≤100 mV at 0.5 mA load - confirming compatibility with standard CMOS/TTL logic thresholds.

Is TSOP77438TT qualified for automotive applications?

No, TSOP77438TT is explicitly stated in the Vishay documentation as "not qualified to automotive specifications." It is rated for −25 °C to +85 °C operating temperature and intended for consumer electronics such as TVs, set-top boxes, and audio systems. For automotive-grade IR receivers, Vishay offers separate AEC-Q200 qualified parts like the TFDU series - TSOP77438TT must not be used in safety-critical or temperature-extended automotive environments.

What is the minimum burst length supported by TSOP77438TT?

TSOP77438TT supports a minimum burst length of 10 cycles at 38 kHz, which corresponds to approximately 263 µs. This is validated for NEC and Sharp protocols per the Vishay parts table and timing diagrams (Fig. 1 and Fig. 4). Bursts shorter than 10 cycles may not be reliably detected, and the device requires a minimum gap time of ≥10 cycles between bursts - a constraint inherent to its AGC4 architecture for noise discrimination.

Can TSOP77438TT be used with 5 V microcontrollers?

Yes, TSOP77438TT supports supply voltages from 2.0 V to 5.5 V, making it fully compatible with 5 V microcontrollers. Its output stage is open-collector and logic-level agnostic - when pulled up to 5 V, the active-low output swings cleanly between ~0 V (≤100 mV at 0.5 mA) and 5 V. No level-shifting is required, and the 5 V supply condition is explicitly tested in the Electrical Characteristics table (ISD = 0.45 mA max at VS = 5 V).