QTM611T1 Equivalent & Substitute Parts

Part Overview

The QTM611T1 is a logic output optoisolator manufactured by QT Brightek, designed for high-speed digital isolation applications. It features 10 Mbps data rate capability, 3750 Vrms isolation voltage, and open collector output with Schottky clamping in a 5-Mini-Flat surface mount package. The device is classified as obsolete, making identification of active equivalent parts essential for ongoing production and maintenance applications.

Substiute Parts

QTM611T1

QT Brightek (QTB)In Stock: 903QTM611T1 Datasheet

Current PartRFQ

ELM611(TA)

Everlight Electronics Co LtdIn Stock: 3046ELM611(TA) Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the QTM611T1 is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Isolation voltage: 3750 Vrms
• Data rate: 10 Mbps
• Output configuration: Open Collector, Schottky Clamped
• Number of channels: 1
• Common mode transient immunity: 20 kV/µs minimum
• Output current capability: 50 mA per channel
• Package footprint: 6-SOIC (0.173", 4.40mm Width), 5 Leads
• Input type: DC
• Supply voltage: 7V

The ELM611(TA) manufactured by Everlight Electronics Co Ltd meets all mandatory electrical and mechanical parameters for direct substitution. Both devices share identical isolation voltage, data rate, output type, channel configuration, CMTI rating, and output current specifications. The physical package dimensions and lead count are equivalent, enabling PCB-level compatibility.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: ELM611(TA)

The ELM611(TA) is the direct functional equivalent for QTM611T1 replacement. Selection rationale:

1. Electrical Equivalence: All critical isolation, switching, and output parameters match or exceed QTM611T1 specifications. Propagation delay variance (100 ns vs. 75 ns maximum) remains within acceptable system timing margins for 10 Mbps applications.

2. Product Status: ELM611(TA) maintains active manufacturing status with Everlight Electronics, ensuring long-term availability and supply chain continuity. QTM611T1 obsolescence necessitates transition to an actively produced equivalent.

3. Regulatory Compliance: Both devices share identical ECCN (EAR99) and HTSUS classifications, maintaining export and import compliance equivalence.

4. Packaging Compatibility: Identical 6-SOIC package footprint (0.173", 4.40mm Width) with 5-lead configuration enables direct PCB-level substitution without layout modification.

5. Temperature Range Consideration: ELM611(TA) operates from -40°C to 85°C. Applications requiring the full -55°C to 85°C range of QTM611T1 must evaluate whether the -40°C lower limit is acceptable for the specific system environment.

6. Moisture Sensitivity: Both devices carry MSL 1 (Unlimited), indicating no moisture sensitivity constraints during storage or handling.

Frequently Asked Questions (FAQ)

Q1: Can ELM611(TA) be used as a direct replacement for QTM611T1 in existing designs?

A: Yes. ELM611(TA) provides electrical and mechanical equivalence across all critical parameters. The identical 6-SOIC package footprint enables direct PCB substitution without layout changes. Verify that the -40°C to 85°C operating range of ELM611(TA) meets your application's temperature requirements, as QTM611T1 extends to -55°C.

Q2: What is the significance of the propagation delay difference (75 ns vs. 100 ns)?

A: The 25 ns difference in maximum propagation delay between QTM611T1 (75 ns) and ELM611(TA) (100 ns) is within acceptable tolerance for 10 Mbps digital isolation applications. System-level timing analysis should confirm that the additional 25 ns delay does not violate setup/hold time requirements in your specific circuit.

Q3: Are there packaging differences between QTM611T1 and ELM611(TA)?

A: Both devices use 6-SOIC (0.173", 4.40mm Width) packages with 5 leads. QTM611T1 is supplied in Mini-Flat packaging, while ELM611(TA) is supplied in Tape & Reel (TR) format. The physical footprint and lead configuration are identical, ensuring PCB compatibility.

Q4: Why is QTM611T1 classified as obsolete?

A: QTM611T1 has reached end-of-life status with QT Brightek. ELM611(TA) represents the active equivalent from Everlight Electronics, ensuring continued availability and manufacturing support for new designs and production requirements.

Q5: Are regulatory certifications equivalent between QTM611T1 and ELM611(TA)?

A: Yes. Both devices carry identical ECCN (EAR99) and HTSUS (8541.49.8000) classifications, maintaining regulatory equivalence for export, import, and trade compliance purposes.

Q6: What is the forward voltage difference, and does it affect circuit design?

A: ELM611(TA) has a typical forward voltage of 1.45V compared to QTM611T1's 1.4V, a difference of 0.05V. This minor variance is within standard component tolerance and does not require circuit redesign for typical LED drive applications.

Q7: Can ELM611(TA) be used in applications requiring -55°C operation?

A: ELM611(TA) is rated for -40°C to 85°C operation. Applications requiring -55°C minimum temperature must either confirm that -40°C is acceptable for their environment or identify alternative optoisolators with extended low-temperature ratings.