A28-LC-7-TT-R DIP Socket 28-Position Equivalent & Substitute Parts

Part Overview

The A28-LC-7-TT-R is a 28-position DIP socket manufactured by Assmann WSW Components, designed for through-hole mounting of dual inline package integrated circuits. This component features 0.3" (7.62mm) row spacing with tin-plated phosphor bronze contacts. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications.

Key Parameters

Parameter	Value
Number of Positions	28 (2 x 14)
Row Spacing	0.3" (7.62mm)
Pitch - Mating	0.100" (2.54mm)
Pitch - Post	0.100" (2.54mm)
Contact Finish - Mating	Tin
Contact Finish - Post	Tin
Mounting Type	Through Hole
Termination	Solder
Operating Temperature Range	-55°C ~ 85°C
Current Rating	1 A
Housing Material	Polybutylene Terephthalate (PBT)
Flammability Rating	UL94 V-0
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the A28-LC-7-TT-R is determined by the following critical parameters:

28-position configuration (2 x 14 arrangement)
0.3" (7.62mm) row spacing
0.100" (2.54mm) pitch for both mating and post contacts
Through-hole solder termination
Tin contact finish on both mating and post surfaces
Open frame design
UL94 V-0 flammability rating
MSL 1 (Unlimited) moisture sensitivity

Parts meeting these core specifications are functionally equivalent for DIP socket applications. Variations in contact material composition, contact resistance values, operating temperature ranges, and current ratings represent performance enhancements or different manufacturing approaches but do not prevent substitution when the primary mechanical and electrical parameters align.

Parameter Comparison

Parameter	A28-LC-7-TT-R	A 28-LC/7-T	ED281DT	110-44-328-41-001000
Manufacturer	Assmann WSW Components	Assmann WSW Components	On Shore Technology Inc.	Mill-Max Manufacturing Corp.
Product Status	Obsolete	Active	Active	Active
Number of Positions	28 (2 x 14)	28 (2 x 14)	28 (2 x 14)	28 (2 x 14)
Row Spacing	0.3" (7.62mm)	0.3" (7.62mm)	0.3" (7.62mm)	0.3" (7.62mm)
Pitch - Mating	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)
Pitch - Post	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)
Contact Finish - Mating	Tin	Tin	Tin	Tin
Contact Finish - Post	Tin	Tin	Tin	Tin
Contact Material - Mating	Phosphor Bronze	Phosphor Bronze	Phosphor Bronze	Beryllium Copper
Contact Material - Post	Phosphor Bronze	Phosphor Bronze	Phosphor Bronze	Brass Alloy
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Termination	Solder	Solder	Solder	Solder
Operating Temperature Range	-55°C ~ 85°C	-55°C ~ 85°C	-55°C ~ 110°C	-55°C ~ 125°C
Current Rating	1 A	1 A	1 A	3 A
Contact Resistance	30mOhm	20mOhm	20mOhm	Not specified
Housing Material	Polybutylene Terephthalate (PBT)	Polybutylene Terephthalate (PBT)	Polybutylene Terephthalate (PBT), Glass Filled	Polycyclohexylenedimethylene Terephthalate (PCT), Polyester
Flammability Rating	UL94 V-0	UL94 V-0	UL94 V-0	Not specified
Moisture Sensitivity Level	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

All three substitute parts—A 28-LC/7-T, ED281DT, and 110-44-328-41-001000—meet the core mechanical and electrical specifications required for direct substitution of the obsolete A28-LC-7-TT-R.

A 28-LC/7-T is the primary direct equivalent, manufactured by the same supplier (Assmann WSW Components) with identical specifications and active product status. This part offers the closest match with ROHS3 compliance and improved contact resistance (20mOhm versus 30mOhm).

ED281DT (On Shore Technology Inc.) provides an active alternative with identical core specifications. The glass-filled PBT housing offers enhanced mechanical properties. Operating temperature range extends to 110°C, providing additional thermal margin. ROHS3 compliance is confirmed.

110-44-328-41-001000 (Mill-Max Manufacturing Corp.) is designated as manufacturer-recommended and offers the highest performance envelope with 3 A current rating and 125°C maximum operating temperature. Different contact materials (beryllium copper mating, brass alloy post) and housing composition (PCT polyester) represent alternative engineering approaches. ROHS3 compliance is confirmed.

All substitute parts carry MSL 1 (Unlimited) moisture sensitivity and REACH Unaffected status, matching the original part's environmental compliance profile.

Frequently Asked Questions (FAQ)

Q: Can A 28-LC/7-T be used as a direct replacement for A28-LC-7-TT-R?

A: Yes. Both parts share identical 28-position DIP configuration, 0.3" row spacing, 0.100" pitch, tin contact finish, through-hole solder termination, and operating temperature range. The primary difference is product status (active versus obsolete) and improved contact resistance specification.

Q: What is the difference between ED281DT and the Assmann parts?

A: ED281DT is manufactured by On Shore Technology Inc. and features glass-filled PBT housing and extended operating temperature range to 110°C. All critical mechanical and electrical parameters remain identical. Contact material composition is phosphor bronze, matching the original specification.

Q: Why does 110-44-328-41-001000 have a 3 A current rating when others are rated 1 A?

A: The 3 A rating reflects the design capability of the Mill-Max part using beryllium copper mating contacts and brass alloy post contacts. This represents enhanced performance but does not prevent substitution in applications requiring 1 A or less. The part remains mechanically and electrically compatible with the original 28-position DIP socket specification.

Q: Are all substitute parts RoHS compliant?

A: Yes. A 28-LC/7-T, ED281DT, and 110-44-328-41-001000 are all ROHS3 compliant. The original A28-LC-7-TT-R does not specify RoHS status.

Q: What packaging formats are available?

A: A 28-LC/7-T is supplied in Box packaging. ED281DT and 110-44-328-41-001000 are supplied in Tube packaging. Packaging format does not affect electrical or mechanical compatibility.

Q: Can these parts be used interchangeably on the same PCB?

A: Yes. All substitute parts maintain identical footprint geometry (28-position DIP, 0.3" row spacing, 0.100" pitch) and through-hole solder termination, enabling direct PCB-level substitution without layout modification.

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