EC103B1 Equivalent & Substitute Parts

Part Overview

The EC103B1 is a Sensitive Gate SCR (Silicon Controlled Rectifier) rated for 200 V off-state voltage with 800 mA on-state current in a TO-92 through-hole package, manufactured by Littelfuse Inc. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The EC103B1 serves in applications requiring thyristor switching control with low gate trigger requirements typical of sensitive gate SCR designs.

Key Parameters

Parameter	Value
Voltage - Off State	200 V
Voltage - Gate Trigger (Vgt) (Max)	800 mV
Current - Gate Trigger (Igt) (Max)	12 µA
Voltage - On State (Vtm) (Max)	1.7 V
Current - On State (It (RMS)) (Max)	800 mA
Current - Hold (Ih) (Max)	5 mA
SCR Type	Sensitive Gate
Operating Temperature	-40°C ~ 110°C
Package / Case	TO-92-3 (TO-226AA)
Mounting Type	Through Hole
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the EC103B1 is determined by the following critical parameters that must remain compatible:

Mandatory Compatibility Parameters:

SCR Type: Sensitive Gate (gate trigger characteristics must match application requirements)
Package / Case: TO-92-3 (TO-226AA) through-hole configuration (physical and electrical pin compatibility)
Mounting Type: Through Hole (PCB assembly compatibility)
Current - On State (It (RMS)): 800 mA (current handling capacity)
Current - Hold (Ih): 5 mA (holding current threshold)
Voltage - Gate Trigger (Vgt): 800 mV maximum (gate sensitivity specification)
RoHS Status: ROHS3 Compliant (regulatory requirement)

Allowable Variation Parameters:

Voltage - Off State: May be equal or higher (200 V minimum acceptable)
Voltage - On State (Vtm): May vary within application tolerance
Current - Gate Trigger (Igt): May be equal or lower
Operating Temperature: May be equal or wider range
Current - Off State: May vary
Current - Non Rep. Surge: May vary

Substitute parts are grouped into two categories: Littelfuse EC103 series upgrades (higher voltage ratings with identical electrical characteristics) and cross-manufacturer alternatives (STMicroelectronics P0118DA 5AL3).

Parameter Comparison

Parameter	EC103B1	EC103D1	EC103M1	P0118DA 5AL3
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	STMicroelectronics
Voltage - Off State	200 V	400 V	600 V	400 V
Voltage - Gate Trigger (Vgt) (Max)	800 mV	800 mV	800 mV	800 mV
Current - Gate Trigger (Igt) (Max)	12 µA	12 µA	12 µA	5 µA
Voltage - On State (Vtm) (Max)	1.7 V	1.7 V	1.7 V	1.95 V
Current - On State (It (RMS)) (Max)	800 mA	800 mA	800 mA	800 mA
Current - Hold (Ih) (Max)	5 mA	5 mA	5 mA	5 mA
Current - Off State (Max)	1 µA	1 µA	1 µA	10 µA
SCR Type	Sensitive Gate	Sensitive Gate	Sensitive Gate	Sensitive Gate
Operating Temperature	-40°C ~ 110°C	-40°C ~ 110°C	-40°C ~ 110°C	-40°C ~ 125°C
Package / Case	TO-92-3 (TO-226AA)	TO-92-3 (TO-226AA)	TO-92-3 (TO-226AA)	TO-92-3 (TO-226AA)
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Product Status	Obsolete	Active	Active	Obsolete
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Littelfuse EC103 Series):

EC103D1 and EC103M1 are direct functional upgrades from Littelfuse Inc. with active product status. Both maintain identical gate trigger voltage (800 mV), gate trigger current (12 µA), on-state voltage (1.7 V), on-state current (800 mA), and hold current (5 mA) specifications. The EC103D1 provides 400 V off-state voltage rating, while EC103M1 provides 600 V off-state voltage rating. Both are suitable for applications where the original 200 V rating is insufficient or where higher voltage margin is required. Active product status ensures long-term availability and supply chain continuity.

Cross-Manufacturer Alternative (STMicroelectronics P0118DA 5AL3):

The P0118DA 5AL3 is a manufacturer-recommended substitute with 400 V off-state voltage rating. This part maintains the 800 mV gate trigger voltage and 800 mA on-state current specifications. Differences include lower gate trigger current (5 µA versus 12 µA), slightly higher on-state voltage (1.95 V versus 1.7 V), and higher off-state leakage current (10 µA versus 1 µA). The P0118DA 5AL3 has an extended operating temperature range (-40°C ~ 125°C versus -40°C ~ 110°C). This part is classified as obsolete; however, it remains available in inventory. All substitute parts maintain ROHS3 compliance and TO-92-3 package compatibility.

Frequently Asked Questions (FAQ)

Q: Can EC103D1 or EC103M1 be used as direct replacements for EC103B1?

A: Yes. EC103D1 and EC103M1 are pin-compatible substitutes with identical sensitive gate SCR electrical characteristics. The higher voltage ratings (400 V and 600 V respectively) provide additional voltage margin without affecting gate trigger behavior or current handling. Both are active products from Littelfuse Inc.

Q: What is the difference between EC103D1 and EC103M1?

A: Both parts are functionally identical except for off-state voltage rating. EC103D1 is rated for 400 V, while EC103M1 is rated for 600 V. Selection depends on the maximum voltage the application will encounter. All other electrical parameters remain identical.

Q: Is the P0118DA 5AL3 a suitable substitute?

A: The P0118DA 5AL3 is a cross-manufacturer alternative with compatible package and gate trigger voltage. However, it exhibits lower gate trigger current (5 µA), higher on-state voltage (1.95 V), and higher off-state leakage current (10 µA) compared to the EC103B1. These differences may affect circuit performance in applications with tight gate drive or leakage current specifications. Verification against application requirements is necessary.

Q: Are all substitute parts in the same package?

A: Yes. All substitute parts use the TO-92-3 (TO-226AA) through-hole package with identical pin configuration, ensuring mechanical and electrical compatibility on existing PCB layouts.

Q: What is the product status significance?

A: EC103D1 and EC103M1 have active product status, ensuring continued manufacturing and supply availability. The EC103B1 and P0118DA 5AL3 are obsolete; however, inventory remains available. For new designs or long-term production, active products are preferred.

Q: Are all parts RoHS compliant?

A: Yes. All listed parts maintain ROHS3 compliance, meeting regulatory requirements for hazardous substance restrictions.

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