EL06XX Series 8-Pin SOP High-Speed 10Mbit/s Logic Gate Photocoupler Datasheet - English Technical Document

1. Product Overview

The EL06XX series represents a family of high-performance, high-speed logic gate photocouplers (opto-isolators). These devices are engineered to provide robust electrical isolation and high-speed digital signal transmission. Each unit integrates an infrared light-emitting diode (LED) optically coupled to a high-speed integrated photodetector with a logic gate output. The output features a strobable function, allowing for controlled signal gating. Packaged in a compact 8-pin Small Outline Package (SOP), these components conform to the standard SO8 footprint, making them suitable for space-constrained applications requiring reliable signal isolation.

1.1 Core Advantages and Target Market

The primary advantage of the EL06XX series lies in its combination of high-speed data transmission (up to 10 Mbit/s) and excellent common-mode transient immunity (CMTI), with the EL0611 variant offering a minimum of 10 kV/μs. This makes it exceptionally resistant to electrical noise in environments with significant ground potential differences. The devices are guaranteed to operate across a wide temperature range from -40°C to 85°C, with an extended operating range up to 100°C. They are designed for applications demanding fast, reliable digital isolation, such as industrial automation, communication interfaces, power supply feedback loops, and computer peripheral interfaces where ground loop elimination is critical. The logic gate output simplifies interface design with standard logic families.

2. Technical Parameter Deep-Dive

This section provides a detailed, objective analysis of the key electrical and performance parameters specified in the datasheet.

2.1 Absolute Maximum Ratings

The Absolute Maximum Ratings define the stress limits beyond which permanent damage to the device may occur. Key limits include: a maximum forward current (IF) of 20 mA for the input LED; a maximum reverse voltage (VR) of 5 V; an enable input voltage (VE) that must not exceed VCC by more than 500mV, with an absolute max of 5.5V; and an output current (IO) capability of 50 mA. The isolation voltage (VISO) is rated at 3750 Vrms for one minute, tested under specific humidity conditions (40-60% RH). The device can withstand soldering temperatures up to 260°C for 10 seconds. Operating outside these ratings is not recommended.

2.2 Electrical Characteristics

The Electrical Characteristics table provides guaranteed performance parameters under specified test conditions. For the input LED, the typical forward voltage (VF) is 1.4V at a forward current (IF) of 10mA, with a maximum of 1.8V. It exhibits a negative temperature coefficient of approximately -1.8 mV/°C. On the output side, supply current varies between a maximum of 10 mA (ICCH, output high) and 13 mA (ICCL, output low) under specific enable and input conditions. The enable input has defined voltage thresholds: a high-level enable voltage (VEH) minimum of 2.0V and a low-level enable voltage (VEL) maximum of 0.8V.

2.3 Transfer Characteristics

Transfer characteristics define the relationship between input and output states. Key parameters include: a maximum high-level output current (IOH) of 100 μA when the output is forced high; a maximum low-level output voltage (VOL) of 0.6V when sinking 13mA; and a maximum input threshold current (IFT) of 5mA required to guarantee a low output state under load. These parameters are crucial for ensuring proper logic level translation and noise margins in the target system.

2.4 Switching Characteristics

The switching performance is critical for high-speed applications. Under standard test conditions (VCC=5V, IF=7.5mA, CL=15pF, RL=350Ω), the propagation delay times are specified: time to output low (TPHL) has a typical of 35 ns and a maximum of 75 ns; time to output high (TPLH) has a typical of 45 ns and a maximum of 75 ns. Pulse width distortion, the absolute difference between TPHL and TPLH, is typically 10 ns with a maximum of 35 ns. Output rise time (tr) is typically 30 ns (max 40 ns), and fall time (tf) is typically 10 ns (max 20 ns). Enable propagation delays are even faster, with tELH (enable to output high) at 30 ns typical and tEHL (enable to output low) at 20 ns typical.

2.5 Common Mode Transient Immunity (CMTI)

CMTI is a measure of the device's ability to reject fast voltage transients between its input and output grounds. The EL06XX series offers different grades: EL0600 has basic CMTI, EL0601 offers 5,000 V/μs minimum, and EL0611 provides 10,000 V/μs minimum under standard test (VCM=400Vp-p). Remarkably, the EL0611 achieves 15,000 V/μs when used with the recommended drive circuit shown in Figure 15 of the datasheet. High CMTI is essential in noisy environments like motor drives and switching power supplies to prevent false triggering.

3. Mechanical and Package Information

The device is housed in a standard 8-pin Small Outline Package (SOP). The pin configuration is as follows: Pin 1: No Connection (NC); Pin 2: Anode (A) of the input LED; Pin 3: Cathode (K) of the input LED; Pin 4: NC; Pin 5: Ground (GND) for the output side; Pin 6: Output Voltage (Vout); Pin 7: Enable Input (VE); Pin 8: Supply Voltage for the output side (VCC). The package conforms to the industry-standard SO8 footprint, ensuring compatibility with automated PCB assembly processes. The datasheet emphasizes that a 0.1μF bypass capacitor must be connected between pins 8 (VCC) and 5 (GND) for stable operation.

4. Application Guidelines and Design Considerations

4.1 Typical Application Scenarios

• Ground Loop Elimination and Logic Level Translation: Isolating digital signals between systems with different ground potentials, such as between a microcontroller and industrial sensor, or translating between LSTTL, TTL, and 5V CMOS logic families.
• Data Communication: Used in line receivers, data transmission systems, and data multiplexing where electrical isolation prevents noise coupling.
• Power Supply Feedback: Providing isolated voltage feedback in switching power supplies, replacing pulse transformers for higher speed and reliability.
• Computer Peripheral Interface: Isolating signals in interfaces like RS-232, RS-485, or general-purpose I/O to protect sensitive logic from transients.

4.2 Design Considerations

• Power Supply Decoupling: The mandatory 0.1μF capacitor between VCC and GND (pins 8 & 5) is critical to minimize supply noise and ensure stable high-speed switching.
• Enable Pin Usage: The active-low enable input (VE) allows for output gating. The truth table indicates the output is forced high when the enable is low (L), regardless of the input state. This can be used for bus contention management or power-saving modes.
• Load Resistor Selection: The switching characteristics are specified with a 350Ω pull-up resistor to VCC. This value should be considered in the design to achieve the specified speed.
• Maximizing CMTI: For applications requiring the highest noise immunity (like the EL0611), the dedicated drive circuit shown in Figure 15 should be implemented. This circuit optimizes the switching performance under high common-mode stress.
• Thermal Management: While power dissipation is low, adhering to the maximum ratings for power dissipation (PD=40mW input, PO=100mW output) and ensuring the operating temperature stays within -40°C to 100°C is necessary for long-term reliability.

5. Technical Comparison and Differentiation

The EL06XX series differentiates itself in the photocoupler market through its specific blend of features. Unlike slower photocouplers (often in the 1-10 kbit/s range) used for basic isolation, this series targets true high-speed digital isolation at 10 Mbit/s. Compared to some other high-speed isolators (which may use capacitive or magnetic coupling), optocouplers like the EL06XX provide inherent galvanic isolation and are often perceived as more robust against high-voltage surges. Within its own family, the key differentiator is the Common Mode Transient Immunity (CMTI). The EL0611, with its 10-15 kV/μs rating, is positioned for the most demanding industrial and power conversion applications, whereas the EL0600/EL0601 serve applications with lower noise requirements. The inclusion of a strobable enable function adds a control feature not always present in basic photocouplers.

6. Frequently Asked Questions (FAQs)

Q: What is the primary purpose of the enable (VE) pin?
A: The enable pin provides a gating function for the output. When VE is driven low (<0.8V), the output is forced high, overriding the state of the input LED. This is useful for tri-stating a bus or putting the output into a known state.

Q: How do I achieve the maximum 15,000 V/μs CMTI rating for the EL0611?
A: The 15,000 V/μs rating is not achieved with the basic connection. You must implement the specific drive circuit recommended in Figure 15 of the datasheet, which includes an external transistor and specific biasing.

Q: Can I drive the input LED directly from a microcontroller GPIO pin?
A: Possibly, but you must calculate the series resistor. For example, with a 3.3V GPIO, a VF of 1.4V, and a desired IF of 10mA, you would need R = (3.3V - 1.4V) / 0.01A = 190Ω. Ensure the GPIO can source/sink the required current and that the forward current does not exceed 20mA.

Q: What is the difference between propagation delay (tPLH/tPHL) and enable propagation delay (tELH/tEHL)?
A> Propagation delay measures the time from a change in the input LED state to a corresponding change at the output. Enable propagation delay measures the time from a change on the enable pin to a change at the output, assuming the input state is already set to cause that change. The enable delays are typically faster.

Q: Is an external pull-up resistor required on the output?
A: Yes. The output is an open-collector/open-drain type. A pull-up resistor (typically 350Ω as used in the test conditions) to VCC is required for the output to swing high.

7. Practical Application Example

Scenario: Isolated SPI Communication in a Motor Drive. A microcontroller on a control board needs to send configuration data via SPI to a driver IC located near a high-power motor. The motor switching creates large ground bounce and common-mode noise. An EL0611 photocoupler can be used to isolate the SPI clock (SCK) and chip select (CS) signals. The high 10,000+ V/μs CMTI ensures the digital signals remain intact despite the noisy environment. The enable pin could be tied low (enabled) or controlled by the microcontroller to gate the signals if needed. The mandatory 0.1μF decoupling capacitor must be placed close to the photocoupler's VCC and GND pins on the isolated side of the board. A 350Ω resistor would pull up each output line to the isolated side's 5V supply.

8. Operating Principle

The fundamental operating principle is optoelectronic isolation. An electrical signal applied to the input side forward-biases an infrared Light Emitting Diode (LED), causing it to emit photons. These photons travel across a transparent insulating gap (providing the galvanic isolation) and strike the photosensitive area of an integrated circuit on the output side. This IC contains a photodiode that converts the light back into a photocurrent. This photocurrent is then processed by a high-speed amplifier and logic gate circuit within the same IC to produce a clean, buffered digital output signal that mirrors the input state. The enable pin acts as a control input to this output logic stage, allowing it to be overridden.

9. Industry Trends and Context

The demand for high-speed signal isolation continues to grow, driven by several trends. In industrial automation and the Industrial Internet of Things (IIoT), there is a need for faster communication between controllers and sensors/actuators in electrically noisy environments. Electric vehicles and renewable energy systems require robust isolation in battery management and power conversion systems handling high voltages and currents. While alternative isolation technologies like capacitive (using SiO2 barriers) and magnetic (using transformers) isolators offer advantages in speed, integration density, and longevity, photocouplers maintain a strong position due to their high withstand voltage, proven reliability, simplicity, and inherent noise immunity. The development focus for photocouplers like the EL06XX series is on pushing data rates higher (beyond 10 Mbit/s), improving CMTI ratings, reducing propagation delay and skew, and enhancing reliability over extended temperature ranges, all while maintaining cost-effectiveness for volume applications.