MAC9D TRIAC 400V 8A TO-220 Equivalent & Substitute Parts

Part Overview

The MAC9D is a standard TRIAC thyristor rated for 400V off-state voltage and 8A on-state current in a TO-220-3 through-hole package. Manufactured by onsemi, this component is classified as obsolete. Due to its obsolete status and limited availability from the original manufacturer, identifying equivalent and substitute parts is necessary for design continuity and procurement flexibility. Substitute parts must maintain electrical compatibility across voltage, current, and thermal operating ranges while accommodating packaging and mounting requirements.

Key Parameters

Parameter	Value
Voltage - Off State	400 V
Current - On State (It (RMS)) (Max)	8 A
Voltage - Gate Trigger (Vgt) (Max)	1.5 V
Current - Gate Trigger (Igt) (Max)	50 mA
Current - Hold (Ih) (Max)	50 mA
Current - Non Rep. Surge 50, 60Hz (Itsm)	80A @ 60Hz
Operating Temperature	-40°C ~ 125°C (TJ)
Mounting Type	Through Hole
Package / Case	TO-220-3
Configuration	Single

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following criteria:

Direct Equivalents maintain identical electrical specifications: 400V off-state voltage, 8A on-state current, 1.5V maximum gate trigger voltage, 50mA maximum gate trigger current, and 50mA maximum hold current. These parts are functionally interchangeable with the MAC9D in standard TRIAC applications.

Compatible Substitutes meet or exceed the MAC9D electrical requirements while introducing controlled parameter variations. Acceptable variations include:

Gate trigger voltage (Vgt) up to 1.3V (lower values reduce gate drive requirements)
Gate trigger current (Igt) up to 50mA (equal or lower)
Hold current (Ih) up to 50mA (equal or lower)
Non-repetitive surge current (Itsm) at or above 80A

Uprated Substitutes provide higher current capacity (12A instead of 8A) or higher voltage ratings (600V instead of 400V). These are suitable when circuit design permits higher ratings and when the application does not require exact current matching.

All substitute parts must maintain TO-220-3 through-hole packaging and -40°C to 125°C operating temperature range.

Parameter Comparison

Part Number	Manufacturer	Triac Type	Voltage - Off State	Current - On State (Max)	Vgt (Max)	Igt (Max)	Ih (Max)	Itsm	Package	Product Status
MAC9D	onsemi	Standard	400 V	8 A	1.5 V	50 mA	50 mA	80A @ 60Hz	TO-220-3	Obsolete
MAC9DG	Littelfuse Inc.	Standard	400 V	8 A	1.5 V	50 mA	50 mA	80A @ 60Hz	TO-220-3	Active
BTA08-400BRG	STMicroelectronics	Standard	400 V	8 A	1.3 V	50 mA	50 mA	80A, 84A	TO-220-3	Active
Q4008R4TP	Littelfuse Inc.	Standard	400 V	8 A	1.3 V	25 mA	50 mA	83A, 100A	TO-220-3	Active
BTB08-600BWRG	STMicroelectronics	Alternistor - Snubberless	600 V	8 A	1.3 V	50 mA	50 mA	80A, 84A	TO-220-3	Active
MAC12HCDG	Littelfuse Inc.	Standard	400 V	12 A	1.5 V	50 mA	60 mA	100A @ 60Hz	TO-220-3	Active
Q4006RH3TP	Littelfuse Inc.	Alternistor - Snubberless	400 V	6 A	1.3 V	10 mA	15 mA	80A, 85A	TO-220-3	Active

Engineering Selection Recommendations

Primary Recommendation: MAC9DG (Littelfuse Inc.)

MAC9DG is the direct equivalent to MAC9D with identical electrical specifications. It is manufactured by Littelfuse Inc., carries active product status, and is ROHS3 compliant. This part provides the most straightforward replacement path with no design modifications required. Inventory availability is 1335 pieces.

Secondary Recommendation: BTA08-400BRG (STMicroelectronics)

BTA08-400BRG maintains 400V and 8A ratings with marginally lower gate trigger voltage (1.3V vs. 1.5V). This reduction in Vgt simplifies gate drive circuits. The part is ROHS3 compliant and active. Inventory availability is 3629 pieces, providing superior supply security.

Alternative for Enhanced Surge Capability: Q4008R4TP (Littelfuse Inc.)

Q4008R4TP provides 400V and 8A ratings with lower gate trigger current (25mA vs. 50mA) and higher non-repetitive surge current (83A, 100A vs. 80A). This part is suitable for applications requiring reduced gate drive power or enhanced transient protection. Product status is active with ROHS3 compliance. Inventory is 1173 pieces.

Uprated Option for Higher Voltage: BTB08-600BWRG (STMicroelectronics)

BTB08-600BWRG is a snubberless TRIAC rated for 600V and 8A. This part is suitable only when circuit design permits higher voltage ratings and when snubberless operation is compatible with the application. It is ROHS3 compliant and active with 1907 pieces in inventory.

Uprated Option for Higher Current: MAC12HCDG (Littelfuse Inc.)

MAC12HCDG provides 400V with increased current capacity of 12A. This part is suitable only when the application can accommodate higher current ratings. It is ROHS3 compliant and active with 4850 pieces in inventory.

Not Recommended: Q4006RH3TP (Littelfuse Inc.)

Q4006RH3TP is rated for only 6A on-state current, below the MAC9D specification of 8A. This part does not meet the current requirement and is not suitable as a substitute.

Frequently Asked Questions (FAQ)

Q: Can MAC9DG directly replace MAC9D without circuit modifications?

A: Yes. MAC9DG is a direct equivalent with identical electrical specifications. No circuit modifications are required. The primary difference is product status: MAC9D is obsolete while MAC9DG is active.

Q: What is the difference between standard TRIAC and Alternistor (snubberless) TRIAC types?

A: Standard TRIACs require external snubber networks for EMI suppression in certain applications. Alternistor snubberless TRIACs incorporate internal snubber functionality, reducing external component requirements. Substitution between these types requires circuit analysis to confirm compatibility.

Q: Can BTA08-400BRG replace MAC9D if gate trigger voltage is lower?

A: Yes. Lower gate trigger voltage (1.3V vs. 1.5V) is compatible and often beneficial, as it reduces gate drive power requirements. The part maintains 400V and 8A ratings and is electrically compatible.

Q: Is MAC12HCDG suitable as a substitute for MAC9D?

A: MAC12HCDG is suitable only if the circuit design permits 12A operation. The higher current rating does not prevent substitution, but the application must not depend on the 8A current limit for protection or operation. Verify that thermal management and circuit protection remain adequate.

Q: What does ROHS3 compliance mean for component selection?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead and other hazardous materials. All active substitute parts listed are ROHS3 compliant, meeting modern environmental and regulatory standards.

Q: Can Q4006RH3TP be used in place of MAC9D?

A: No. Q4006RH3TP is rated for 6A maximum on-state current, which is below the MAC9D specification of 8A. This part cannot meet the current requirement and is not suitable.

Q: What packaging differences exist among the substitute parts?

A: All substitute parts use TO-220-3 through-hole packaging, maintaining mechanical and thermal compatibility with MAC9D. Packaging variations (Tube vs. Box) affect only procurement and handling, not electrical or mechanical performance.

Q: How does non-repetitive surge current (Itsm) affect substitution decisions?

A: Itsm defines the maximum transient current the TRIAC can withstand. Higher Itsm values provide greater protection against voltage spikes and transient events. Parts with Itsm equal to or exceeding 80A are compatible. Higher values do not prevent substitution.

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