onsemi HCPL2611S

Overview

HCPL2611S from ON Semiconductor (formerly Fairchild) is a single-channel, high-speed logic gate optocoupler with 10 Mbit/s data rate, 10 kV/µs common-mode transient immunity (CMTI), and open-collector strobable output. It isolates digital signals between LSTTL/TTL/CMOS domains in switching power supplies and industrial bus interfaces.

For engineers reviewing the HCPL2611S datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed CMTI ≥10 kV/µs at V_CM = 400 V, propagation delay ≤75 ns over –40°C to +85°C, fan-out of 8 into TTL loads, and UL recognition (File # E90700).

Technical Context

The HCPL2611S integrates an 850 nm AlGaAs LED coupled to a monolithic photodetector IC with built-in noise shield and logic-gate output stage. Its strobable enable input allows synchronous gating of output transitions without external latching.

It operates with 4.5–5.5 V V_CC, accepts 5 mA input current for guaranteed 13 mA sink output (fan-out of 8), and maintains <0.6 V low-level output voltage under 13 mA load across full temperature range. The internal pull-up on the enable pin eliminates need for external biasing.

Key Specifications

Pinout & Package

HCPL2611S uses an 8-pin DIP-8 surface-mount package (lead bend type S) with 0.3-inch wide body and gull-wing leads. A 0.1 µF bypass capacitor must be placed between pins 8 (V_CC) and 5 (GND).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed logic gate optocoupler applications.

Compared with 6N137S and HCPL2601S, HCPL2611S delivers superior common-mode noise rejection essential for demanding industrial isolation-its 10 kV/µs CMTI is not matched by either alternative, making it the only choice when system-level EMC robustness is non-negotiable.

Availability

HCPL2611S is available at Aetrix Electronics and suitable for switching power supplies, motor drive gate control, and industrial serial interfaces requiring stable component supply and long-term lifecycle support.

Supply support for HCPL2611S 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

ON Semiconductor (formerly Fairchild Semiconductor) is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete devices for automotive, industrial, and cloud power applications.

The HCPL2611S belongs to ON Semiconductor's legacy high-speed optocoupler product line, engineered specifically for noise-immune digital signal isolation in industrial automation and power electronics systems.

FAQ

What is the maximum operating temperature range for HCPL2611S?

The HCPL2611S is fully specified and guaranteed over an operating temperature range of –40°C to +85°C. All key parameters-including propagation delay, CMTI, fan-out, and output voltage-are validated across this range. This makes HCPL2611S suitable for deployment in industrial control cabinets, motor drives, and outdoor power conversion equipment where ambient temperatures exceed consumer-grade limits. No derating is required within this span.

Does HCPL2611S require an external pull-up resistor on its output pin?

Yes, HCPL2611S features an open-collector output (pin 6, VO), which requires an external pull-up resistor to V_CC (pin 7). Typical values range from 330 Ω to 1 kΩ depending on rise time and drive strength needs. The device does not include an internal pull-up on the output-only the enable input (pin 4) has an internal pull-up, eliminating the need for an external resistor there. Always place a 0.1 µF ceramic capacitor between pins 8 (V_CC) and 5 (GND) for stable operation.

How does the enable input (VE) function in HCPL2611S?

The enable input (pin 4, VE) is an active-HIGH strobe that controls output state independently of the LED input. When VE ≥ 2.0 V, the output reflects the LED state (LOW when LED is ON); when VE ≤ 0.8 V, the output is forced HIGH (high-impedance state is not supported). HCPL2611S includes an internal pull-up on VE, so no external resistor is needed unless actively driving it LOW. This feature enables synchronized gating in multi-channel systems and supports safe default states during reset sequences.

What is the minimum common-mode transient immunity (CMTI) of HCPL2611S, and under what conditions is it tested?

The HCPL2611S guarantees a minimum CMTI of 10 kV/µs at V_CM = 400 V peak, measured at both output HIGH and LOW states (|CMH| and |CML|). This value is confirmed per Figure 14 test circuit in the datasheet, using a 350 Ω load and 15 pF capacitance. It exceeds the 5 kV/µs rating of HCPL2601S and 6N137S, making HCPL2611S uniquely suited for high-noise applications like IGBT gate drive feedback and variable-frequency drive control circuits.

Is HCPL2611S still recommended for new designs?

No-HCPL2611S is marked "NOT RECOMMENDED FOR NEW DESIGN" in the official datasheet. While fully functional and supported for existing production, ON Semiconductor advises evaluating newer alternatives such as the FODM8071 or Si87xx series for new projects due to improved power efficiency, smaller footprints, and enhanced lifetime reliability. HCPL2611S remains available for legacy design refresh, repair, and long-lifecycle industrial programs where qualification stability is prioritized over next-generation features.