K3021P Optoisolator Triac Output Equivalent & Substitute Parts

Part Overview

The K3021P is a 5.3kVrms optoisolator with triac output manufactured by Vishay Semiconductor Opto Division in a 6-DIP package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The K3021P provides galvanic isolation for triac-based switching applications with a single channel configuration and 400V off-state voltage rating.

Key Parameters

Parameter	K3021P Value
Manufacturer	Vishay Semiconductor Opto Division
Category	Optoisolators
Output Type	Triac
Number of Channels	1
Voltage - Isolation	5300Vrms
Voltage - Off State	400 V
Static dV/dt (Min)	10V/µs (Typ)
Current - LED Trigger (Ift) (Max)	15mA
Current - On State (It (RMS)) (Max)	100 mA
Current - Hold (Ih)	200µA (Typ)
Voltage - Forward (Vf) (Typ)	1.3V
Current - DC Forward (If) (Max)	80 mA
Operating Temperature	-55°C ~ 100°C
Mounting Type	Through Hole
Package / Case	6-DIP (0.300", 7.62mm)
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the K3021P is determined by the following critical parameters:

Mandatory Compatibility Criteria:

Output Type: Triac
Number of Channels: 1
Voltage - Isolation: Minimum 5000Vrms (K3021P operates at 5300Vrms)
Voltage - Off State: 400 V
Package / Case: 6-DIP through-hole configuration
Operating Temperature Range: -55°C ~ 100°C minimum
Mounting Type: Through Hole

Functional Equivalence Parameters:

Current - On State (It (RMS)): 100 mA (standard across all candidates)
Current - Hold (Ih): Comparable performance (200-250µA range acceptable)
Voltage - Forward (Vf): 1.18-1.3V range acceptable for LED input stage

Acceptable Variation Parameters:

Current - LED Trigger (Ift): 5-15mA range acceptable (lower values indicate improved sensitivity)
Static dV/dt: 10-100V/µs range acceptable (higher values indicate improved noise immunity)
Current - DC Forward (If): 50-80mA range acceptable

Everlight Electronics EL302x series parts meet all mandatory criteria and are classified as active products. The MOC3020 from onsemi matches isolation voltage and package specifications but is also obsolete.

Parameter Comparison

Parameter	K3021P	EL3021-V	EL3021M	EL3021M-V	EL3022-V	EL3022M	EL3022M-V	EL3023-V	EL3023M	EL3023M-V	MOC3020
Manufacturer	Vishay	Everlight	Everlight	Everlight	Everlight	Everlight	Everlight	Everlight	Everlight	Everlight	onsemi
Output Type	Triac	Triac	Triac	Triac	Triac	Triac	Triac	Triac	Triac	Triac	Triac
Number of Channels	1	1	1	1	1	1	1	1	1	1	1
Voltage - Isolation	5300Vrms	5000Vrms	5000Vrms	5000Vrms	5000Vrms	5000Vrms	5000Vrms	5000Vrms	5000Vrms	5000Vrms	5300Vrms
Voltage - Off State	400 V	400 V	400 V	400 V	400 V	400 V	400 V	400 V	400 V	400 V	400 V
Static dV/dt (Min)	10V/µs (Typ)	100V/µs (Typ)	100V/µs (Typ)	100V/µs (Typ)	100V/µs (Typ)	100V/µs (Typ)	100V/µs (Typ)	100V/µs (Typ)	100V/µs (Typ)	100V/µs (Typ)	Not specified
Current - LED Trigger (Ift) (Max)	15mA	15mA	15mA	15mA	10mA	10mA	10mA	5mA	5mA	5mA	30mA
Current - On State (It (RMS)) (Max)	100 mA	100 mA	100 mA	100 mA	100 mA	100 mA	100 mA	100 mA	100 mA	100 mA	Not specified
Current - Hold (Ih)	200µA (Typ)	250µA (Typ)	250µA (Typ)	250µA (Typ)	250µA (Typ)	250µA (Typ)	250µA (Typ)	250µA (Typ)	250µA (Typ)	250µA (Typ)	100µA
Voltage - Forward (Vf) (Typ)	1.3V	1.18V	1.18V	1.18V	1.18V	1.18V	1.18V	1.18V	1.18V	1.18V	Not specified
Current - DC Forward (If) (Max)	80 mA	60 mA	60 mA	60 mA	60 mA	60 mA	60 mA	60 mA	60 mA	60 mA	50 mA
Operating Temperature	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	6-DIP (0.300", 7.62mm)	6-DIP (0.300", 7.62mm)	6-DIP (0.400", 10.16mm)	6-DIP (0.400", 10.16mm)	6-DIP (0.300", 7.62mm)	6-DIP (0.400", 10.16mm)	6-DIP (0.400", 10.16mm)	6-DIP (0.300", 7.62mm)	6-DIP (0.400", 10.16mm)	6-DIP (0.400", 10.16mm)	6-DIP (0.300", 7.62mm)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	Not specified
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active	Obsolete

Engineering Selection Recommendations

Primary Substitute Recommendation: Everlight EL302x Series

The Everlight Electronics EL3021, EL3022, and EL3023 series optoisolators are active products suitable for replacing the obsolete K3021P. All Everlight candidates maintain the required 5000Vrms isolation voltage, 400V off-state rating, and 100mA on-state current specification. The EL302x series provides improved static dV/dt performance (100V/µs versus 10V/µs) and lower LED trigger current requirements, resulting in enhanced noise immunity and reduced input drive requirements.

Package Selection Guidance:

For direct PCB compatibility with existing K3021P footprints, select parts with 6-DIP (0.300", 7.62mm) package designation: EL3021-V, EL3022-V, or EL3023-V. These maintain identical pitch and body dimensions to the original K3021P.

For applications where PCB layout permits, the 6-DIP (0.400", 10.16mm) variants (EL3021M, EL3021M-V, EL3022M, EL3022M-V, EL3023M, EL3023M-V) offer the same electrical performance with wider body spacing.

LED Trigger Current Variants:

EL3021 series: 15mA LED trigger current (closest match to K3021P specification) EL3022 series: 10mA LED trigger current (reduced input drive requirement) EL3023 series: 5mA LED trigger current (minimum input drive requirement)

Selection depends on available input drive current in the application circuit.

Compliance Considerations:

All Everlight EL302x candidates are ROHS3 compliant. Everlight parts with -V suffix designation include VDE approval. Standard EL302x variants include CSA, DEMKO, FIMKO, NEMKO, SEMKO, and UL certifications. Select the variant matching your regional compliance requirements.

Secondary Option: MOC3020

The onsemi MOC3020 matches the K3021P isolation voltage (5300Vrms) and package dimensions (6-DIP 0.300", 7.62mm) but is also classified as obsolete. The MOC3020 exhibits higher LED trigger current (30mA maximum) and lower hold current (100µA) compared to K3021P specifications. This part is not recommended for new designs due to obsolete status.

Frequently Asked Questions (FAQ)

Q: Can I use an EL3022 or EL3023 as a direct replacement for K3021P?

A: Yes. All EL302x series parts meet the mandatory compatibility criteria: triac output, single channel, 5000Vrms isolation (exceeds K3021P 5300Vrms requirement), 400V off-state voltage, 100mA on-state current, and -55°C to 100°C operating range. The primary difference is reduced LED trigger current (10mA for EL3022, 5mA for EL3023 versus 15mA for K3021P), which reduces input drive requirements. Verify your circuit can supply the required LED forward current before selection.

Q: What is the difference between EL3021-V and EL3021M?

A: Both parts are electrically identical EL3021 optoisolators with 15mA LED trigger current. The difference is package body width: EL3021-V uses 6-DIP (0.300", 7.62mm) matching K3021P footprint, while EL3021M uses 6-DIP (0.400", 10.16mm) with wider spacing. Select based on PCB layout requirements. The -V suffix indicates VDE approval inclusion.

Q: Why do EL3023 parts have lower LED trigger current than K3021P?

A: The EL3023 series is designed for applications requiring minimal input drive current (5mA maximum). This represents improved LED efficiency in the optoisolator input stage. If your circuit provides 15mA input drive, the EL3023 will operate reliably with reduced power consumption. If your circuit provides exactly 15mA with no margin, the EL3021 (15mA rated) provides closer specification matching.

Q: Are there package compatibility issues between 0.300" and 0.400" DIP variants?

A: Yes. The 0.300" (7.62mm) and 0.400" (10.16mm) designations refer to body width. These are not interchangeable on the same PCB without layout modification. The 0.300" variants fit existing K3021P footprints. The 0.400" variants require wider DIP socket spacing or modified PCB traces. Verify your PCB layout before selecting the wider variant.

Q: What certifications should I verify for my application?

A: All Everlight EL302x parts are ROHS3 compliant. For regional requirements: EL302x parts with -V suffix include VDE approval. Standard EL302x variants include CSA, DEMKO, FIMKO, NEMKO, SEMKO, and UL certifications. Consult your application's compliance requirements and select the variant with matching agency approvals.

Q: Is the MOC3020 a suitable replacement?

A: The MOC3020 is obsolete and not recommended for new designs. Although it matches K3021P isolation voltage and package, its obsolete status creates long-term supply risk. The active Everlight EL302x series provides superior performance with guaranteed availability.

Q: How does improved dV/dt performance affect my circuit?

A: The EL302x series provides 100V/µs static dV/dt (typical) compared to K3021P 10V/µs. Higher dV/dt rating indicates improved immunity to rapid voltage transients on the triac output. This reduces false triggering risk in noisy environments. If your application operates in high-noise conditions, the EL302x series offers enhanced reliability.

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