MAC8NG TRIAC 800V 8A Equivalent & Substitute Parts

Part Overview

The MAC8NG is a standard TRIAC thyristor manufactured by Littelfuse Inc., rated for 800V off-state voltage and 8A on-state current in a TO-220-3 through-hole package. This component is active in production and ROHS3 compliant. Equivalent and substitute parts are identified based on matching or exceeding electrical specifications within the same package category, enabling direct replacement or functional substitution in circuit applications requiring 800V/8A TRIAC functionality.

Key Parameters

Parameter	MAC8NG Specification
Voltage - Off State	800 V
Current - On State (It RMS Max)	8 A
Voltage - Gate Trigger (Vgt Max)	1.5 V
Current - Gate Trigger (Igt Max)	35 mA
Current - Hold (Ih Max)	40 mA
Current - Non Rep. Surge (Itsm)	80 A @ 60Hz
Operating Temperature Range	-40°C to 125°C (TJ)
Mounting Type	Through Hole
Package / Case	TO-220-3
TRIAC Type	Standard
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following criteria:

Electrical Compatibility Requirements:

Voltage - Off State: Must equal or exceed 800V
Current - On State (It RMS): Must equal or exceed 8A
Package / Case: Must be TO-220-3 or compatible TO-220 variant
Mounting Type: Must be Through Hole
Configuration: Must be Single

Acceptable Variations:

Gate trigger voltage (Vgt) and current (Igt) may vary within standard TRIAC specifications
Hold current (Ih) may vary
Surge current (Itsm) may exceed specification
Operating temperature range may exceed specification
TRIAC type (Standard, Alternistor, Logic-Sensitive Gate) may differ provided electrical ratings are met

Substitutes are grouped into three categories:

Direct Equivalents (Same Current Rating - 8A): Parts with 8A on-state current matching the MAC8NG
Upgraded Substitutes (Higher Current Rating - 12A+): Parts with current ratings exceeding 8A, suitable for applications with margin requirements
Specialized Variants: Alternistor or Logic-Sensitive Gate types offering enhanced performance characteristics

Parameter Comparison

Part Number	Manufacturer	TRIAC Type	Voltage (V)	Current (A)	Vgt Max (V)	Igt Max (mA)	Ih Max (mA)	Itsm (A)	Temp Range (°C)	Package
MAC8NG	Littelfuse Inc.	Standard	800	8	1.5	35	40	80 @ 60Hz	-40 to 125	TO-220-3
Q8008RH4TP	Littelfuse Inc.	Alternistor - Snubberless	800	8	1.3	35	35	83, 100	-40 to 125	TO-220
ACST830-8T	STMicroelectronics	Standard	800	8	1.0	30	30	80, 84	-40 to 125	TO-220-3
T835T-8T	STMicroelectronics	Alternistor - Snubberless	800	8	1.3	35	40	60, 63	-40 to 150	TO-220-3
T635T-8T	STMicroelectronics	Alternistor - Snubberless	800	6	1.3	35	40	45, 47	-40 to 150	TO-220-3
T1235T-8T	STMicroelectronics	Alternistor - Snubberless	800	12	1.3	35	40	90, 95	-40 to 150	TO-220-3
T1635T-8T	STMicroelectronics	Alternistor - Snubberless	800	16	1.3	35	40	120, 126	-40 to 150	TO-220-3
BT138-800,127	WeEn Semiconductors	Standard	800	12	1.5	35	30	95, 105	-40 to 125	TO-220-3
BT138-800E,127	WeEn Semiconductors	Logic - Sensitive Gate	800	12	1.5	10	30	90, 100	-40 to 125	TO-220-3
BTA312-800C,127	WeEn Semiconductors	Standard	800	12	1.5	35	35	95, 105	-40 to 125	TO-220-3
BTA312-800CT,127	WeEn Semiconductors	Standard	800	12	1.0	35	35	100, 110	-40 to 150	TO-220-3

Engineering Selection Recommendations

Direct Equivalent (Same Current Rating):

ACST830-8T (STMicroelectronics): Matches 8A current rating with identical 800V voltage. Standard TRIAC type. ROHS3 compliant. Lower gate trigger voltage (1.0V) and current (30mA) provide improved gate sensitivity.
Q8008RH4TP (Littelfuse Inc.): Matches 8A current rating. Alternistor type offers snubberless operation. ROHS3 compliant. Slightly lower gate trigger voltage (1.3V).
T835T-8T (STMicroelectronics): Matches 8A current rating. Alternistor type with extended temperature range to 150°C. ROHS3 compliant.

Upgraded Substitutes (12A Current Rating):

BT138-800,127 (WeEn Semiconductors): 12A rating provides 50% current margin over MAC8NG. Standard TRIAC type. ROHS3 compliant. Identical gate specifications to MAC8NG.
BTA312-800C,127 (WeEn Semiconductors): 12A rating with standard TRIAC type. ROHS3 compliant. Slightly higher hold current (35mA).
BTA312-800CT,127 (WeEn Semiconductors): 12A rating with extended temperature range to 150°C. Lower gate trigger voltage (1.0V). ROHS3 compliant.
T1235T-8T (STMicroelectronics): 12A rating with Alternistor type. Extended temperature range to 150°C. ROHS3 compliant.

Specialized Variant (Sensitive Gate Logic):

BT138-800E,127 (WeEn Semiconductors): 12A rating with Logic-Sensitive Gate type. Significantly reduced gate trigger current (10mA vs. 35mA) for applications requiring minimal gate drive. ROHS3 compliant.

Higher Current Margin (16A):

T1635T-8T (STMicroelectronics): 16A rating provides 100% current margin. Alternistor type with extended temperature range to 150°C. ROHS3 compliant.

Lower Current Rating (Not Recommended for Direct Substitution):

T635T-8T (STMicroelectronics): 6A rating is below MAC8NG specification. Suitable only for applications with reduced current requirements.

All substitute parts maintain ROHS3 compliance and are active in production status.

Frequently Asked Questions (FAQ)

Q: Can I use a 12A TRIAC as a substitute for the 8A MAC8NG? A: Yes. Parts rated for 12A on-state current (BT138-800,127; BTA312-800C,127; BTA312-800CT,127; T1235T-8T) are direct substitutes. The higher current rating provides operational margin and does not affect circuit function when the application current requirement is 8A or less.

Q: What is the difference between Standard and Alternistor TRIAC types? A: Alternistor (Snubberless) types are optimized for operation without external snubber networks, reducing component count. Standard types may require snubber circuits in certain applications. Both types meet the 800V/8A electrical requirements for MAC8NG substitution.

Q: Can I use the T635T-8T (6A) instead of MAC8NG (8A)? A: No. The T635T-8T is rated for 6A maximum on-state current, which is below the MAC8NG specification. Use only if your application current requirement is confirmed to be 6A or less.

Q: Are all substitute parts compatible with the TO-220-3 footprint? A: All listed substitutes use TO-220-3 or compatible TO-220 package variants with identical pin configuration and mounting holes. Q8008RH4TP uses TO-220 Non-Isolated Tab; verify mechanical compatibility with your PCB layout.

Q: What is the advantage of the BT138-800E,127 (Sensitive Gate) variant? A: The BT138-800E,127 requires only 10mA gate trigger current versus 35mA for standard types. This reduces gate drive circuit complexity and power consumption in applications with limited gate drive capability.

Q: Do all substitutes maintain the same operating temperature range as MAC8NG? A: No. MAC8NG operates from -40°C to 125°C. STMicroelectronics Alternistor types (T835T-8T, T1235T-8T, T1635T-8T) and BTA312-800CT,127 extend to 150°C. Select based on your thermal environment requirements.

Q: Are all substitutes ROHS3 compliant? A: Yes. All listed substitute parts are ROHS3 compliant, matching the MAC8NG compliance status.

Q: Which substitute offers the best gate sensitivity? A: BTA312-800CT,127 and ACST830-8T both feature 1.0V gate trigger voltage (versus 1.5V for MAC8NG), providing improved gate sensitivity. BT138-800E,127 offers the lowest gate trigger current at 10mA.

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