Littelfuse S602ES SCR 600V 1.5A TO-92 Equivalent & Substitute Parts

Part Overview

The Littelfuse S602ES is a sensitive gate silicon controlled rectifier (SCR) rated for 600V off-state voltage and 1.5A RMS on-state current in a through-hole TO-92 package. This component is classified as Active product status and is ROHS3 compliant. Equivalent and substitute parts are identified based on matching electrical characteristics within the 600V voltage class and compatible gate-triggering parameters, enabling direct replacement in applications where the primary part is unavailable or where alternative packaging or current ratings are acceptable.

Key Parameters

Parameter	S602ES Value	Unit
Voltage - Off State	600	V
Voltage - Gate Trigger (Vgt) Max	800	mV
Current - Gate Trigger (Igt) Max	200	µA
Voltage - On State (Vtm) Max	1.7	V
Current - On State (It RMS) Max	1.5	A
Current - Hold (Ih) Max	5	mA
Current - Off State Max	5	µA
Operating Temperature Range	-40 to 125	°C
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3	—
SCR Type	Sensitive Gate	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the S602ES is determined by the following critical parameters:

Off-State Voltage: All substitutes must maintain 600V rating to ensure blocking capability in the application circuit.
Gate Trigger Characteristics: Vgt (Max) of 800 mV and Igt (Max) of 200 µA define gate sensitivity. Substitutes with equal or lower Igt values are compatible.
On-State Voltage (Vtm): Maximum 1.7V for the S602ES; substitutes with lower Vtm values reduce conduction losses.
On-State Current (It RMS): The S602ES is rated for 1.5A RMS. Substitutes rated at 800 mA or 1.25A RMS represent lower current capability; substitutes at 1.5A or higher maintain or exceed the original rating.
Package and Mounting: All substitutes use TO-92-3 through-hole configuration, ensuring mechanical and electrical compatibility.
Temperature Range: All substitutes operate across -40°C to 125°C, matching the original specification.
Compliance: All substitutes are ROHS3 compliant and REACH unaffected, maintaining regulatory alignment.

Substitutes are grouped into three categories based on current rating: lower current (800 mA RMS), intermediate current (1.25A RMS), and equivalent current (1.5A RMS).

Parameter Comparison

Part Number	Manufacturer	Voff (V)	Vgt Max (mV)	Igt Max (µA)	Vtm Max (V)	It RMS Max (A)	Ih Max (mA)	Ioff Max (µA)	Package	Packaging Type
S602ES	Littelfuse Inc.	600	800	200	1.7	1.5	5	5	TO-92-3	Bulk
S6X8ES	Littelfuse Inc.	600	800	200	1.7	0.8	5	3	TO-92-3	Bulk
P0111MA 1AA3	STMicroelectronics	600	800	25	1.95	0.8	5	10	TO-92-3	Bulk
X00602MA 1AA2	STMicroelectronics	600	800	200	1.35	0.8	5	1	TO-92-3	Bulk
X00602MA 5AL2	STMicroelectronics	600	800	200	1.35	0.8	5	1	TO-92-3	Cut Tape (CT)
X00619MA 5AL2	STMicroelectronics	600	800	200	1.35	0.8	5	1	TO-92-3	Cut Tape (CT)
X0202MA 1BA2	STMicroelectronics	600	800	200	1.45	1.25	5	5	TO-92-3	Bulk
X0202MA 2BL2	STMicroelectronics	600	800	200	1.45	1.25	5	5	TO-92-3	Cut Tape (CT)

Engineering Selection Recommendations

Direct Equivalents (Matching Current Rating)

The S602ES has no direct equivalent from the substitute list at the 1.5A RMS rating. The closest current-rated substitutes are the X0202MA series at 1.25A RMS, which provide 83% of the original current capacity. These parts are suitable for applications where the full 1.5A capability is not required or where thermal derating is acceptable.

Lower Current Substitutes (800 mA RMS)

The S6X8ES (Littelfuse), P0111MA 1AA3 (STMicroelectronics), X00602MA 1AA2, X00602MA 5AL2, and X00619MA 5AL2 (all STMicroelectronics) are rated for 800 mA RMS, representing 53% of the original current capacity. These substitutes are applicable only in circuits designed for or tolerant of reduced current handling. The X00602MA and X00619MA variants offer superior on-state voltage performance (Vtm = 1.35V vs. 1.7V), reducing conduction losses.

Intermediate Current Substitutes (1.25A RMS)

The X0202MA 1BA2 (Bulk packaging) and X0202MA 2BL2 (Cut Tape packaging) provide 1.25A RMS current rating, representing 83% of the original specification. These parts maintain gate trigger characteristics identical to the S602ES and are suitable for applications where the 1.5A rating can be reduced to 1.25A without circuit redesign.

Packaging and Compliance Considerations

All substitutes are ROHS3 compliant and REACH unaffected, matching the regulatory status of the S602ES. Bulk packaging variants (1AA2, 1BA2) are suitable for manufacturing environments; Cut Tape variants (5AL2, 2BL2) are appropriate for automated pick-and-place assembly. The choice between packaging types does not affect electrical performance.

Product Status and Availability

All substitute parts maintain Active product status, ensuring continued availability and support. Inventory levels vary; selection should account for supply chain requirements and lead time constraints.

Frequently Asked Questions (FAQ)

Q: Can the S6X8ES replace the S602ES in all applications?

A: The S6X8ES is a parametric equivalent with identical gate trigger characteristics and on-state voltage, but is rated for 800 mA RMS versus the S602ES 1.5A RMS. Substitution is valid only if the application circuit operates at or below 800 mA RMS. Exceeding this current rating will cause thermal stress and potential device failure.

Q: What is the difference between X00602MA 1AA2 and X00602MA 5AL2?

A: Both parts are electrically identical with 600V off-state voltage, 800 mA RMS current rating, and 1.35V on-state voltage. The difference is packaging: 1AA2 is supplied in Bulk format, while 5AL2 is supplied in Cut Tape with formed leads. Select based on assembly process requirements.

Q: Are the X0202MA parts suitable as direct replacements for the S602ES?

A: The X0202MA 1BA2 and X0202MA 2BL2 are suitable substitutes with 1.25A RMS rating, representing 83% of the S602ES 1.5A capability. They maintain identical gate trigger parameters (Vgt 800 mV, Igt 200 µA) and operate across the same temperature range. Substitution is valid if the application can tolerate the reduced current margin.

Q: Why do some substitutes have lower Igt (gate trigger current) values?

A: The P0111MA 1AA3 specifies Igt Max of 25 µA, compared to 200 µA for the S602ES. Lower Igt values indicate higher gate sensitivity, requiring less gate current to trigger the SCR. This may affect gate drive circuit design and should be evaluated for compatibility with existing trigger circuits.

Q: Can I use an 800 mA rated substitute in a 1.5A application?

A: No. Using an 800 mA rated device in a 1.5A application will cause the device to operate beyond its rated current capacity, resulting in excessive junction temperature, reduced reliability, and potential catastrophic failure. Application current requirements must not exceed the substitute part's It RMS rating.

Q: Are all substitutes compatible with the original TO-92-3 PCB footprint?

A: Yes. All substitute parts use the TO-92-3 (TO-226-3) package with through-hole leads, ensuring mechanical and electrical compatibility with the original S602ES footprint. Formed lead variants (5AL2, 2BL2) may require different insertion force but maintain the same pin spacing and hole diameter requirements.

Q: What is the significance of the on-state voltage (Vtm) differences?

A: On-state voltage directly affects conduction losses and heat dissipation. The S602ES specifies Vtm Max of 1.7V. Substitutes with lower Vtm values (e.g., X00602MA at 1.35V) dissipate less power during conduction, reducing thermal load. Substitutes with higher Vtm values (e.g., P0111MA at 1.95V) increase conduction losses and may require additional thermal management.

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