VOS618AT Optoisolator - Equivalent & Substitute Parts

Part Overview

The VOS618AT is an optoisolator with transistor output manufactured by Vishay Semiconductor Opto Division. This component provides 3750Vrms isolation with a single channel configuration in a 4-SSOP surface mount package. The part is currently active in production with 2700 units in stock. Substitute parts become necessary when the primary part experiences supply constraints, extended lead times, or when design flexibility permits selection from qualified alternatives that meet identical electrical and mechanical specifications.

Substiute Parts

VOS618AT

Vishay Semiconductor Opto DivisionIn Stock: 2761VOS618AT Datasheet

Current PartRFQ

VOS618A-X001T

Vishay Semiconductor Opto DivisionIn Stock: 20497VOS618A-X001T Datasheet

Parametric EquivalentRFQ

EL3H7(A)(EA)-G

Everlight Electronics Co LtdIn Stock: 2858EL3H7(A)(EA)-G Datasheet

MFR RecommendedRFQ

EL3H7(A)-G

Everlight Electronics Co LtdIn Stock: 2115EL3H7(A)-G Datasheet

MFR RecommendedRFQ

EL3H7(B)(TA)-VG

Everlight Electronics Co LtdIn Stock: 1519EL3H7(B)(TA)-VG Datasheet

MFR RecommendedRFQ

EL3H7(B)-G

Everlight Electronics Co LtdIn Stock: 1683EL3H7(B)-G Datasheet

MFR RecommendedRFQ

EL3H7(EA)-VG

Everlight Electronics Co LtdIn Stock: 3901EL3H7(EA)-VG Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the VOS618AT is determined by strict equivalence across the following critical parameters:

• Isolation Voltage: 3750Vrms (mandatory match)
• Number of Channels: 1 (mandatory match)
• Output Type: Transistor (mandatory match)
• Package / Case: 4-SOIC (0.173", 4.40mm Width) (mandatory match)
• Mounting Type: Surface Mount (mandatory match)
• Maximum Output Voltage: 80V (mandatory match)
• Maximum Output Current: 50mA (mandatory match)
• Operating Temperature Range: -55°C ~ 110°C (mandatory match)
• RoHS Compliance: ROHS3 Compliant (mandatory match)

Substitute parts are grouped into two categories:

Category 1: Parametric Equivalent (Identical Specifications)

• VOS618A-X001T: Identical electrical and mechanical specifications to VOS618AT

Category 2: Manufacturer Recommended Alternatives (Everlight EL3H7 Series)

• EL3H7(A)(EA)-G, EL3H7(A)-G, EL3H7(B)(TA)-VG, EL3H7(B)-G, EL3H7(EA)-VG: Meet all mandatory parameters with variations in Current Transfer Ratio ranges and packaging formats

Parameter Comparison

Engineering Selection Recommendations

VOS618A-X001T (Vishay) This part is a direct parametric equivalent to VOS618AT with identical electrical specifications and compliance certifications. Selection of this substitute is appropriate when supply of the primary part is constrained while maintaining identical performance characteristics. Both parts carry ROHS3 compliance and MSL 1 rating.

EL3H7 Series (Everlight) The Everlight EL3H7 series variants meet all mandatory substitution criteria including isolation voltage, channel count, output type, package dimensions, and operating temperature range. All variants are ROHS3 compliant with MSL 1 rating. Differences exist in Current Transfer Ratio specifications and packaging formats:

• EL3H7(A)(EA)-G and EL3H7(A)-G: Current Transfer Ratio 80-160% @ 5mA
• EL3H7(B)(TA)-VG and EL3H7(B)-G: Current Transfer Ratio 130-260% @ 5mA
• EL3H7(EA)-VG: Current Transfer Ratio 50-600% @ 5mA

All Everlight variants feature lower Vce saturation (200mV maximum) compared to VOS618AT (400mV maximum), indicating improved switching performance. Packaging format variations (Tape & Reel, Tube, Cut Tape & Digi-Reel) accommodate different assembly and procurement workflows.

Frequently Asked Questions (FAQ)

Q: Can EL3H7 series parts directly replace VOS618AT in existing designs? A: Yes. All EL3H7 variants meet the mandatory electrical and mechanical parameters: 3750Vrms isolation, single channel transistor output, 80V maximum output voltage, 50mA output current, 4-SOIC package, and -55°C to 110°C operating range. Differences in Current Transfer Ratio and Vce saturation do not prevent functional substitution but should be evaluated against circuit design margins.

Q: What is the difference between VOS618AT and VOS618A-X001T? A: VOS618A-X001T is a parametric equivalent manufactured by the same supplier (Vishay). Electrical specifications, package dimensions, and compliance certifications are identical. The primary difference is packaging format designation and inventory availability (20400 units for VOS618A-X001T versus 2700 units for VOS618AT).

Q: How do Current Transfer Ratio variations affect circuit performance? A: Current Transfer Ratio determines the output current relative to input current. VOS618AT specifies 50-600% @ 1mA. Everlight variants specify different ranges at 5mA input current. Circuit designs must account for these specifications when calculating output drive capability and signal propagation characteristics.

Q: Are all substitute parts ROHS3 compliant? A: Yes. VOS618AT, VOS618A-X001T, and all EL3H7 variants carry ROHS3 compliance certification. All parts have MSL 1 (Unlimited) moisture sensitivity rating.

Q: What packaging formats are available for substitute parts? A: VOS618AT and VOS618A-X001T are supplied in Tape & Reel format. EL3H7 variants are available in Tape & Reel (EL3H7(A)(EA)-G, EL3H7(EA)-VG), Tube (EL3H7(A)-G, EL3H7(B)-G), and Cut Tape & Digi-Reel format (EL3H7(B)(TA)-VG). Packaging selection depends on assembly equipment compatibility and procurement volume requirements.

Q: Is the lower Vce saturation of EL3H7 parts advantageous? A: EL3H7 variants specify 200mV maximum Vce saturation compared to 400mV for VOS618AT. Lower saturation voltage reduces power dissipation in the output transistor and improves switching efficiency. This represents a performance advantage in applications sensitive to output stage power consumption.