LTV 354T Optocoupler SOP-4

LTV-354T Optocoupler SOP-4 is a high-performance, compact surface-mount optoisolator designed to safely transfer digital signals between two electrically isolated circuits. This device uses an infrared light-emitting diode (LED) on the input side and a high-sensitivity phototransistor on the output side to achieve optical coupling. Consequently, it provides critical galvanic isolation, effectively preventing high voltage spikes and ground loops from affecting sensitive downstream components like microcontrollers. Furthermore, its small SOP-4 package makes the LTV-354T ideal for densely packed printed circuit boards where space optimization is essential. Therefore, designers frequently choose this optocoupler for power supply feedback loops, switching power supplies, and general noise isolation applications.

Key Features:

• High Isolation Voltage: The device offers high input-to-output isolation, typically rated at 3750 V_RMS, guaranteeing robust protection against electrical transients.
• Compact SOP-4 Package: The Small Outline Package (SOP-4) features a low profile and small footprint, making it highly suitable for miniaturized and portable electronics.
• High Current Transfer Ratio (CTR): The LTV-354T provides a minimum CTR range of 50% to 600%, ensuring efficient signal transfer with low input current.
• Fast Switching Speed: Achieves typical rise and fall times in the microsecond range, supporting adequate data transfer rates for digital and switching applications.
• VDE and UL Certified: Meets major international safety standards, confirming its reliability and suitability for commercial products.

Technical Specifications:

• Isolation Voltage (V_ISO): 3750 V_RMS minimum
• Current Transfer Ratio (CTR): 50% to 600% at I_F = 5 mA, V_CE = 5 V
• Collector-Emitter Voltage (V_CEO): 70 V maximum
• Collector Current (I_C): 50 mA maximum
• Input LED Forward Voltage (V_F): ≈ 1.2 V (Typically 1.1 V to 1.5 V)
• Operating Temperature Range: −55°C to +110°C

Mechanical Specifications:

• Package Type: SOP-4 (Small Outline Package, 4-pin)
• Mounting: Surface Mount Technology (SMT)
• Lead Material: Solderable Alloy
• Pitch (Lead Spacing): 1.27 mm (Standard for SOP-4)

Dimensions:

• Body Length: ≈ 4.4 mm
• Body Width: ≈ 2.5 mm
• Body Height (Max): ≈ 2.1 mm (Low Profile)
• Creepage Distance: ≥ 5 mm
• Weight: < 0.1 g (Extremely light)

Pinout and Wiring:

• Pin 1 (Anode): Connect to the positive input signal supply (V_CC) via a current-limiting resistor.
• Pin 2 (Cathode): Connect to the input ground or the output of the driving logic/microcontroller pin.
• Pin 3 (Emitter): Connect to the output ground of the isolated circuit.
• Pin 4 (Collector): Connect to the pull-up resistor (R_L) and the isolated supply voltage (V_CC2) to obtain the output signal.
• Wiring Note: Ensure you keep the input circuit (Pins 1 & 2) and the output circuit (Pins 3 & 4) physically separated to maintain the high isolation barrier.

Datasheet Reference:

• Download Lite-On LTV-354T Optocoupler Datasheet

Commonly Used in:

• Switching Power Supplies (SMPS): Essential for regulating voltage in the feedback loop for isolated DC-DC converters and AC-DC adapters.
• Industrial Control Systems: Used extensively for noise immunity and isolating digital I/O signals from high-voltage motor drivers or sensors.
• Battery Management Systems (BMS): Provides safe signal communication between high-voltage battery packs and low-voltage monitoring circuits.

Applications:

• Signal Isolation: Isolating communications buses (e.g., I²C, SPI, UART) between different voltage domains.
• Noise Reduction: Eliminating ground loop currents and common-mode noise in high-fidelity audio equipment or sensitive measurement instruments.
• Logic Level Shifting: Safely shifting logic signals from one voltage (e.g., 5V) to another (e.g., 3.3V) while providing isolation.

Equivalent Models:

• PC3H7 (Sharp): A similar single-channel phototransistor optocoupler in a compact SOP-4 package, often used as a direct replacement.
• TLP181 (Toshiba): A high-performance, small package optocoupler, however, verify the specific CTR binning when choosing this equivalent.
• EL354T (Everlight): Functionally equivalent to the LTV-354T, offering the same compact footprint and isolation specifications.

Package Includes:

• 1 x LTV-354T Optocoupler SOP-4