Q4008R4TP TRIAC 400V 8A Equivalent & Substitute Parts

Part Overview

The Q4008R4TP is a standard TRIAC manufactured by Littelfuse Inc., rated for 400V off-state voltage and 8A on-state current in a through-hole TO-220AB-R package. This component is active in production with full RoHS3 compliance and unlimited moisture sensitivity rating. Substitute parts are identified when equivalent electrical ratings and mechanical compatibility are maintained across the specified parameter set.

Key Parameters

Parameter	Value	Unit
Voltage - Off State	400	V
Current - On State (It (RMS)) (Max)	8	A
Voltage - Gate Trigger (Vgt) (Max)	1.3	V
Current - Gate Trigger (Igt) (Max)	25	mA
Current - Hold (Ih) (Max)	50	mA
Operating Temperature Range	-40 to 125	°C
Mounting Type	Through Hole	-
Package / Case	TO-220-3	-

Substitute Part Grouping Explanation

Substitution eligibility for the Q4008R4TP is determined by the following criteria:

Off-state voltage rating must equal or exceed 400V
On-state current rating must equal or exceed 8A
Gate trigger voltage (Vgt) must not exceed 1.3V
Gate trigger current (Igt) must not exceed 25mA
Hold current (Ih) must not exceed 50mA
Operating temperature range must encompass -40°C to 125°C
Mounting type must be through-hole
Package must be TO-220-3 or compatible TO-220 variant
Product status must be active
RoHS3 compliance required

The BTA08-400BRG from STMicroelectronics meets all substitution criteria within these parameters.

Parameter Comparison

Parameter	Q4008R4TP (Littelfuse)	BTA08-400BRG (STMicroelectronics)	Match Status
Voltage - Off State	400V	400V	Equivalent
Current - On State (It (RMS)) (Max)	8A	8A	Equivalent
Voltage - Gate Trigger (Vgt) (Max)	1.3V	1.3V	Equivalent
Current - Gate Trigger (Igt) (Max)	25mA	50mA	Substitute Exceeds Specification
Current - Hold (Ih) (Max)	50mA	50mA	Equivalent
Operating Temperature Range	-40 to 125°C	-40 to 125°C	Equivalent
Mounting Type	Through Hole	Through Hole	Equivalent
Package / Case	TO-220-3	TO-220-3	Equivalent
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Equivalent
Product Status	Active	Active	Equivalent

Engineering Selection Recommendations

Both the Q4008R4TP and BTA08-400BRG are active production components with ROHS3 compliance and REACH unaffected status. The BTA08-400BRG presents a direct functional substitute with matching voltage and current ratings. The gate trigger current specification of the BTA08-400BRG (50mA maximum) exceeds the Q4008R4TP specification (25mA maximum), which does not restrict substitution in applications where the circuit design accommodates this parameter variance. Both components share identical operating temperature ranges, package configurations, and regulatory compliance certifications. Selection between these parts may be determined by availability, lead time, or specific circuit gate drive requirements.

Frequently Asked Questions (FAQ)

Q: Can the BTA08-400BRG directly replace the Q4008R4TP in existing designs?

A: Yes, the BTA08-400BRG is functionally equivalent for the specified electrical parameters. Both components are rated for 400V off-state voltage, 8A on-state current, and operate across -40°C to 125°C. Both use TO-220-3 through-hole packages and maintain ROHS3 compliance.

Q: What is the significance of the gate trigger current difference?

A: The BTA08-400BRG has a maximum gate trigger current of 50mA compared to the Q4008R4TP at 25mA. This parameter defines the maximum gate current required for device triggering. The higher specification of the substitute part does not prevent substitution; it indicates the substitute may require slightly higher gate drive current in worst-case conditions.

Q: Are there any package compatibility concerns?

A: No. Both components use TO-220-3 through-hole packages with identical mechanical footprints and pin configurations, ensuring direct PCB compatibility.

Q: Do both parts meet the same regulatory requirements?

A: Yes. Both the Q4008R4TP and BTA08-400BRG are ROHS3 compliant, REACH unaffected, and classified under ECCN EAR99 with identical HTSUS codes.

Q: What determines whether a part qualifies as a substitute?

A: Substitution is based on matching or exceeding the main part's electrical ratings (voltage, current, temperature range), maintaining compatible package specifications, and confirming active product status with equivalent regulatory compliance.

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