TIC126D-S Equivalent & Substitute Parts

Part Overview

The TIC126D-S is a silicon controlled rectifier (SCR) rated for 400V off-state voltage and 12A RMS on-state current in a TO-220-3 through-hole package, manufactured by Bourns Inc. This part is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements. The TIC126D-S operates across a temperature range of -40°C to 110°C and features standard recovery characteristics with a maximum on-state voltage of 1.4V.

Key Parameters

Parameter	Value	Unit
Voltage - Off State	400	V
Current - On State (It (RMS)) (Max)	12	A
Voltage - On State (Vtm) (Max)	1.4	V
Voltage - Gate Trigger (Vgt) (Max)	1.5	V
Current - Gate Trigger (Igt) (Max)	20	mA
Current - Hold (Ih) (Max)	40	mA
SCR Type	Standard Recovery	-
Operating Temperature Range	-40 to 110	°C
Package / Case	TO-220-3	-
Mounting Type	Through Hole	-
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution for the TIC126D-S is determined by the following critical parameters:

Off-state voltage rating: 400V minimum
On-state current rating: 12A RMS minimum
SCR type: Standard Recovery (matching recovery characteristics)
Package compatibility: TO-220-3 through-hole configuration
Gate trigger specifications: Vgt ≤ 1.5V and Igt ≤ 20mA for direct compatibility
On-state voltage: Vtm ≤ 1.4V preferred for thermal performance equivalence
Hold current: Ih ≤ 40mA for circuit stability

Substitute parts are grouped into two categories:

Direct Equivalents (matching all critical parameters): Parts with 400V rating, 12A RMS current, standard recovery type, and compatible gate characteristics.

Functional Alternatives (meeting core requirements with parameter variations): Parts with 400V rating and 12A RMS current but differing in secondary parameters such as on-state voltage, gate trigger current, or operating temperature range. These remain electrically compatible for most applications but may require circuit evaluation.

Parameter Comparison

Parameter	TIC126D-S (Main)	MCR12DG	2N6397G	2N6397TG	MCR72-6G	MCR72-6TG	MCR218-6G
Manufacturer	Bourns Inc.	onsemi	Littelfuse Inc.	Littelfuse	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.
Voltage - Off State (V)	400	400	400	400	400	400	400
Current - On State (It (RMS)) (Max) (A)	12	12	12	12	8	8	8
Voltage - On State (Vtm) (Max) (V)	1.4	2.2	2.2	2.2	2	2	1.8
Voltage - Gate Trigger (Vgt) (Max) (V)	1.5	1	1.5	1.5	1.5	1.5	1.5
Current - Gate Trigger (Igt) (Max)	20 mA	20 mA	30 mA	30 mA	200 µA	200 µA	25 mA
Current - Hold (Ih) (Max)	40 mA	40 mA	50 mA	50 mA	6 mA	6 mA	30 mA
Current - Off State (Max)	2 mA	10 µA	10 µA	10 µA	10 µA	10 µA	10 µA
SCR Type	Standard Recovery	Standard Recovery	Standard Recovery	Standard Recovery	Sensitive Gate	Sensitive Gate	Standard Recovery
Operating Temperature Range (°C)	-40 to 110	-40 to 125	-40 to 125	-40 to 125	-40 to 110	-40 to 110	-40 to 125
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalents for 12A Applications:

MCR12DG (onsemi) is the closest functional equivalent, matching the 12A RMS current rating, 400V off-state voltage, and standard recovery type. It features a lower maximum gate trigger voltage (1V vs. 1.5V) and identical hold current (40mA), with extended operating temperature to 125°C. This part is active in production with ROHS3 compliance and REACH affected status.

2N6397G and 2N6397TG (Littelfuse Inc.) both provide 12A RMS current and 400V rating with standard recovery characteristics. These parts have slightly elevated on-state voltage (2.2V) and gate trigger current (30mA) compared to the TIC126D-S, but remain within acceptable substitution parameters. Both are active with ROHS3 compliance and REACH unaffected status. 2N6397TG is supplied in tube packaging, while 2N6397G is supplied in box packaging.

Functional Alternatives for 8A Applications:

MCR72-6G and MCR72-6TG (Littelfuse Inc.) are sensitive gate SCRs rated for 8A RMS current at 400V. These parts feature significantly lower gate trigger current (200µA vs. 20mA), which may require circuit redesign for gate drive compatibility. MCR72-6G is supplied in box packaging; MCR72-6TG is supplied in tube packaging. Both are active with ROHS3 compliance and REACH unaffected status.

MCR218-6G (Littelfuse Inc.) is an 8A standard recovery SCR with 400V rating and the lowest on-state voltage (1.8V) among substitutes. This part is active with ROHS3 compliance and REACH unaffected status, supplied in box packaging.

Compliance and Availability:

All substitute parts are ROHS3 compliant and active in production, eliminating obsolescence risk. MCR12DG carries REACH affected status, while all Littelfuse alternatives are REACH unaffected. Inventory availability ranges from 1,220 to 5,100 pieces across substitute options.

Frequently Asked Questions (FAQ)

Q: Can MCR72-6G or MCR72-6TG replace the TIC126D-S in a 12A application?

A: No. These parts are rated for 8A RMS maximum on-state current, which is insufficient for 12A applications. They are functional alternatives only for circuits designed for 8A operation.

Q: What is the primary difference between MCR72-6G and MCR72-6TG?

A: Both parts are electrically identical sensitive gate SCRs with 400V and 8A ratings. The difference is packaging: MCR72-6G is supplied in box packaging, while MCR72-6TG is supplied in tube packaging.

Q: Is MCR12DG a direct replacement for TIC126D-S?

A: MCR12DG meets the core electrical requirements: 400V off-state voltage, 12A RMS on-state current, standard recovery type, and TO-220-3 package. The lower gate trigger voltage (1V vs. 1.5V) and extended temperature range (125°C vs. 110°C) are improvements. Circuit validation is recommended for gate drive compatibility.

Q: Why do 2N6397G and 2N6397TG have higher on-state voltage than TIC126D-S?

A: On-state voltage variation is a normal characteristic across different manufacturers and production lots. The 2.2V maximum for these parts remains within acceptable limits for most power control applications, though thermal dissipation will be slightly higher than the TIC126D-S at 1.4V.

Q: Can I use MCR218-6G in place of TIC126D-S?

A: MCR218-6G is rated for 8A RMS, not 12A. It is not suitable for applications requiring the full 12A current capacity of the TIC126D-S.

Q: What is the difference between standard recovery and sensitive gate SCRs?

A: Standard recovery SCRs (TIC126D-S, MCR12DG, 2N6397G, 2N6397TG, MCR218-6G) require higher gate trigger current (typically 20-30mA) for reliable triggering. Sensitive gate SCRs (MCR72-6G, MCR72-6TG) require only microampere-level gate trigger current (200µA), enabling lower-power gate drive circuits. Substitution between these types requires gate drive circuit redesign.

Q: Are all substitute parts RoHS compliant?

A: Yes. All substitute parts listed are ROHS3 compliant. The TIC126D-S is also ROHS3 compliant.

Q: What is REACH affected vs. REACH unaffected status?

A: REACH affected status (MCR12DG) indicates the part may contain substances of very high concern (SVHC) requiring compliance documentation. REACH unaffected status indicates no known SVHC content. Both statuses are compliant with current regulations; the distinction affects documentation requirements in supply chains.

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