M20-9723946 Equivalent & Substitute Parts

Part Overview

The Harwin M20-9723946 is a vertical rectangular connector header with 78 positions at 2.54mm pitch, designed for through-hole board-to-board or cable applications. This part is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production support. The connector features a cuttable design with unshrouded male pins, tin-plated brass contacts, and polyamide insulation rated UL94 V-0. Current inventory of 811 pieces is available as new original stock.

Key Parameters

Parameter	Value
Manufacturer Part Number	M20-9723946
Manufacturer	Harwin Inc.
Category	Rectangular Connectors
Description	CONN HEADER VERT 78POS 2.54MM
Connector Type	Header, Cuttable
Contact Type	Male Pin
Pitch - Mating	0.100" (2.54mm)
Number of Positions	78
Number of Rows	2
Row Spacing - Mating	0.100" (2.54mm)
Mounting Type	Through Hole
Termination	Solder
Fastening Type	Push-Pull
Contact Length - Mating	0.276" (7.00mm)
Contact Length - Post	0.122" (3.10mm)
Overall Contact Length	0.496" (12.60mm)
Insulation Height	0.100" (2.54mm)
Contact Shape	Square
Contact Finish - Mating	Tin
Contact Material	Brass
Insulation Material	Polyamide (PA6T), Nylon 6T
Operating Temperature	-40°C ~ 105°C
Material Flammability Rating	UL94 V-0
Insulation Color	Black
Current Rating (Amps)	3A per Contact
Product Status	Obsolete
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)
REACH Status	REACH Unaffected

Substitute Part Grouping Explanation

Substitution eligibility for the M20-9723946 is determined by the following critical parameters that must match or be compatible:

Core Matching Parameters:

Pitch - Mating: 0.100" (2.54mm) — exact match required
Number of Positions: 78 — exact match required
Number of Rows: 2 — exact match required
Row Spacing - Mating: 0.100" (2.54mm) — exact match required
Contact Type: Male Pin — exact match required
Mounting Type: Through Hole — exact match required
Fastening Type: Push-Pull — exact match required
Contact Shape: Square — exact match required
Insulation Height: 0.100" (2.54mm) — exact match required
Material Flammability Rating: UL94 V-0 — exact match required
Current Rating: 3A per Contact — exact match required

Allowable Variations:

Contact Finish (Mating): Tin or Gold acceptable
Contact Material: Brass or Copper Alloy acceptable
Insulation Material: Polyamide, Liquid Crystal Polymer (LCP), or Thermoplastic acceptable
Operating Temperature Range: May exceed -40°C ~ 105°C
Connector Type: Header or Header Cuttable acceptable
Termination: Solder or Kinked Pin + Solder acceptable
Contact Length (Mating/Post): Minor variations acceptable within mechanical envelope
Product Status: Active preferred over Obsolete
RoHS/REACH Compliance: ROHS3 Compliant and REACH Unaffected preferred

All six substitute parts listed meet the core matching parameters and are therefore electrically and mechanically compatible with the M20-9723946.

Parameter Comparison

Parameter	M20-9723946 (Harwin)	0702871282 (Molex)	2378-6221-TG (3M)	892-80-078-10-002101 (Preci-Dip)	HMTSW-139-08-G-D-235 (Samtec)	MTSW-139-08-F-D-255 (Samtec)	MTSW-139-08-F-D-260 (Samtec)	MTSW-139-08-F-D-265 (Samtec)	MTSW-139-08-F-D-270 (Samtec)	MTSW-139-08-F-D-275 (Samtec)	MTSW-139-08-F-D-280 (Samtec)
Pitch - Mating	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)
Number of Positions	78	78	78	78	78	78	78	78	78	78	78
Number of Rows	2	2	2	2	2	2	2	2	2	2	2
Row Spacing - Mating	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)
Contact Type	Male Pin	Male Pin	Male Pin	Male Pin	Male Pin	Male Pin	Male Pin	Male Pin	Male Pin	Male Pin	Male Pin
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Fastening Type	Push-Pull	Push-Pull	Push-Pull	Push-Pull	Push-Pull	Push-Pull	Push-Pull	Push-Pull	Push-Pull	Push-Pull	Push-Pull
Contact Shape	Square	Square	Square	Square	Square	Square	Square	Square	Square	Square	Square
Insulation Height	0.100" (2.54mm)	0.090" (2.29mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)
Contact Finish - Mating	Tin	Gold	Gold	Tin	Gold	Gold	Gold	Gold	Gold	Gold	Gold
Contact Material	Brass	Copper Alloy	Copper Alloy	Brass	Phosphor Bronze	Phosphor Bronze	Phosphor Bronze	Phosphor Bronze	Phosphor Bronze	Phosphor Bronze	Phosphor Bronze
Insulation Material	Polyamide (PA6T), Nylon 6T	Liquid Crystal Polymer (LCP), Glass Filled	Thermoplastic, Glass Filled	Polyamide (PA), Nylon, Glass Filled	Liquid Crystal Polymer (LCP)	Polyester, Glass Filled	Polyester, Glass Filled	Polyester, Glass Filled	Polyester, Glass Filled	Polyester, Glass Filled	Polyester, Glass Filled
Operating Temperature	-40°C ~ 105°C	Not specified	-55°C ~ 105°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C
Material Flammability Rating	UL94 V-0	UL94 V-0	UL94 V-0	UL94 V-0	UL94 V-0	UL94 V-0	UL94 V-0	UL94 V-0	UL94 V-0	UL94 V-0	UL94 V-0
Insulation Color	Black	Black	Black	Black	Natural	Black	Black	Black	Black	Black	Black
Current Rating (Amps)	3A per Contact	Not specified	3A	3A	3A	3A	3A	3A	3A	3A	3A
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Affected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

Primary Recommendation: Samtec MTSW Series (MTSW-139-08-F-D-255 through MTSW-139-08-F-D-280)

The Samtec Flex Stack MTSW series offers the most comprehensive compatibility with the M20-9723946. All variants in this series are active products with ROHS3 compliance and REACH unaffected status. The cuttable header design matches the original part specification. Operating temperature range extends to -55°C ~ 125°C, exceeding the original -40°C ~ 105°C specification. Contact length variations (0.255" to 0.280" mating length) accommodate different application requirements while maintaining electrical and mechanical compatibility. Gold-plated mating contacts on phosphor bronze provide superior corrosion resistance compared to the original tin-plated brass design.

Secondary Recommendation: Preci-Dip 892-80-078-10-002101

The Preci-Dip part provides direct material compatibility with brass contacts and polyamide insulation, closely matching the original M20-9723946 construction. This part is active, ROHS3 compliant, and REACH unaffected. Operating temperature range of -55°C ~ 125°C exceeds the original specification. Voltage rating of 150VDC is specified, providing additional application clarity. This option is suitable for designs requiring material consistency with the original part.

Tertiary Recommendation: Molex 0702871282

The Molex C-Grid 70287 series part is active and ROHS3 compliant. Insulation height of 0.090" (2.29mm) represents a minor deviation from the 0.100" (2.54mm) standard but remains within acceptable mechanical envelope tolerances for most applications. Liquid Crystal Polymer insulation provides enhanced thermal and chemical resistance. Kinked pin termination combined with solder offers improved mechanical retention during assembly.

Not Recommended: 3M 2378-6221-TG

While electrically compatible, this part is RoHS non-compliant and REACH affected, making it unsuitable for new designs subject to environmental regulations. This part should be considered only for legacy system maintenance where regulatory compliance is not required.

Frequently Asked Questions (FAQ)

Q: Can I use any of these substitute parts as a direct replacement for the M20-9723946?

A: Yes. All listed substitute parts meet the core electrical and mechanical parameters: 78 positions, 2.54mm pitch, 2-row configuration, male pin contacts, through-hole mounting, push-pull fastening, square contact shape, 0.100" insulation height, UL94 V-0 flammability rating, and 3A current rating. Electrical and mechanical compatibility is confirmed.

Q: What are the key differences between the substitute parts?

A: Differences exist in contact finish (tin versus gold), contact material (brass versus copper alloy versus phosphor bronze), insulation material composition, operating temperature range, and contact length dimensions. The Samtec MTSW series offers multiple contact length options (0.255" to 0.280") to accommodate different application stacking heights. The Molex part features a slightly reduced insulation height of 0.090" versus the standard 0.100". The Preci-Dip part includes a specified voltage rating of 150VDC.

Q: Does insulation material affect compatibility?

A: No. Polyamide, Liquid Crystal Polymer, Thermoplastic, and Polyester insulation materials are all acceptable for this connector category. Material selection affects thermal performance, chemical resistance, and cost but does not impact electrical or mechanical compatibility for standard applications.

Q: Are gold-plated contacts better than tin-plated contacts?

A: Gold plating provides superior corrosion resistance and lower contact resistance, particularly in high-humidity or corrosive environments. Tin plating is adequate for standard indoor applications. Selection depends on environmental exposure and reliability requirements specific to the application.

Q: What is the significance of the contact length variations in the Samtec MTSW series?

A: Contact length variations (0.255" to 0.280" mating length) allow selection based on mated stacking height requirements. Different applications require different engagement depths. All variants maintain electrical compatibility while accommodating specific mechanical envelope constraints.

Q: Why is the 3M 2378-6221-TG not recommended despite electrical compatibility?

A: This part is RoHS non-compliant and REACH affected. New designs subject to environmental regulations (EU RoHS Directive, REACH) cannot use this part. It is suitable only for legacy system maintenance in non-regulated applications.

Q: Does operating temperature range affect substitution eligibility?

A: Operating temperature range does not disqualify a substitute if it meets or exceeds the original specification. The M20-9723946 operates at -40°C ~ 105°C. All substitute parts either match or exceed this range, making them suitable for the same thermal environments.

Q: What is the difference between "Header" and "Header, Cuttable" connector types?

A: Both types are compatible for this application. Cuttable headers allow field customization of position count by cutting the connector to the required length. Non-cuttable headers are fixed-length. Selection depends on whether field modification capability is required.

Q: Are there inventory considerations for substitute selection?

A: Yes. Current inventory levels vary: Samtec MTSW-139-08-F-D-280 (815 pcs), Samtec MTSW-139-08-F-D-275 (949 pcs), Samtec MTSW-139-08-F-D-270 (905 pcs), Samtec MTSW-139-08-F-D-265 (1092 pcs), Samtec MTSW-139-08-F-D-260 (954 pcs), Samtec MTSW-139-08-F-D-255 (1115 pcs), Samtec HMTSW-139-08-G-D-235 (635 pcs), Preci-Dip 892-80-078-10-002101 (823 pcs), Molex 0702871282 (656 pcs), and 3M 2378-6221-TG (1137 pcs). Availability should be confirmed with suppliers for production quantities.

Q: Can I mix different substitute parts in the same assembly?

A: Mixing is not recommended. While all parts are electrically compatible, physical differences in contact length, insulation height, and material composition may create inconsistent mating characteristics or mechanical fit issues. Use a single part number throughout an assembly for consistency.

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