KAJ03TAGT DIP Switch Equivalent & Substitute Parts

Part Overview

The KAJ03TAGT is a 3-position DIP switch manufactured by E-Switch, configured as a single-pole single-throw (SPST) switch rated for 25mA at 24VDC. This component features a slide actuator with gold-plated copper alloy contacts and is designed for through-hole mounting with PC pin termination. The product is currently obsolete, making identification of compatible substitute parts essential for ongoing system support and new design implementations.

Key Parameters

Parameter	Value
Manufacturer Part Number	KAJ03TAGT
Manufacturer	E-Switch
Circuit Configuration	SPST
Number of Positions	3
Current Rating	25mA
Voltage Rating	24VDC
Actuator Type	Slide (Standard)
Mounting Type	Through Hole
Termination Style	PC Pin
Pitch	0.100" (2.54mm)
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the KAJ03TAGT is determined by the following critical parameters that must be maintained or exceeded:

Mandatory Compatibility Parameters:

Circuit configuration: SPST (single-pole single-throw)
Number of positions: 3
Mounting type: Through hole
Termination style: PC pin
Pitch: 0.100" (2.54mm)
Actuator type: Slide (standard)
Actuator level: Flush, recessed

Electrical Performance Parameters:

Current rating: Substitute must support minimum 25mA
Voltage rating: Substitute must support minimum 24VDC
Operating temperature range: -40°C to 85°C

Regulatory Compliance:

RoHS3 compliance required
MSL rating: 1 (Unlimited)

Both identified substitute parts (209-3LPST and SD03H0B) meet or exceed these parameters. The 209-3LPST provides 100mA at 20VDC, while the SD03H0B provides 100mA at 25VDC, both representing electrical upgrades from the original 25mA at 24VDC specification.

Parameter Comparison

Parameter	KAJ03TAGT (Original)	209-3LPST (CTS)	SD03H0B (C&K)
Circuit Configuration	SPST	SPST	SPST
Number of Positions	3	3	3
Current Rating (Amps)	25mA	100mA	100mA
Voltage Rating	24VDC	20VDC	25VDC
Actuator Type	Slide (Standard)	Slide (Standard)	Slide (Standard)
Actuator Level	Flush, Recessed	Flush, Recessed	Flush, Recessed
Contact Material	Copper Alloy	Beryllium Copper	Beryllium Copper
Contact Finish	Gold	Gold	Gold
Height Above Board	0.142" (3.60mm)	0.180" (4.57mm)	0.178" (4.52mm)
Mounting Type	Through Hole	Through Hole	Through Hole
Termination Style	PC Pin	PC Pin	PC Pin
Pitch	0.100" (2.54mm)	0.100" (2.54mm)	0.100" (2.54mm)
Washable	Yes	Yes	Yes
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Electrical Life	2,000 Cycles	2,000 Cycles	2,000 Cycles
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
Product Status	Obsolete	Active	Active

Engineering Selection Recommendations

Both substitute parts are suitable replacements for the obsolete KAJ03TAGT based on electrical and mechanical compatibility.

209-3LPST (CTS Electrocomponents): This part is actively manufactured and maintains ROHS3 compliance. It provides enhanced current capacity (100mA versus 25mA) but operates at a lower voltage rating (20VDC versus 24VDC). This part is appropriate for applications where the 24VDC requirement can be reduced to 20VDC or where the application operates below 20VDC. The increased height above board (0.180" versus 0.142") must be verified against PCB layout constraints.

SD03H0B (C&K): This part is actively manufactured and maintains ROHS3 compliance. It provides enhanced current capacity (100mA versus 25mA) while matching the original voltage rating (25VDC). The height above board (0.178" versus 0.142") is comparable to the 209-3LPST and must be verified against PCB layout constraints. This part is the preferred substitute when the original 24VDC specification must be maintained.

Both parts feature beryllium copper contacts versus the original copper alloy, providing improved contact reliability and longevity. Both are available in active production with established supply chains.

Frequently Asked Questions (FAQ)

Q: Can the 209-3LPST be used in a 24VDC circuit? A: The 209-3LPST is rated for 20VDC maximum. Use in a 24VDC circuit exceeds the component's voltage specification and is not recommended. The SD03H0B is the appropriate choice for 24VDC applications.

Q: What is the significance of the increased current rating in the substitute parts? A: Both substitute parts are rated for 100mA, compared to the original 25mA rating. This represents a four-fold increase in current capacity. The substitutes can safely handle the original 25mA load with additional margin. Higher current ratings do not negatively impact lower-current applications.

Q: How does the increased height above board affect PCB design? A: The substitute parts are approximately 0.036" to 0.038" taller than the original KAJ03TAGT. PCB layouts must accommodate this increased height. Verify clearance with adjacent components, solder mask patterns, and any conformal coating or potting processes.

Q: Are the substitute parts pin-compatible with the original? A: Yes. Both substitute parts maintain the same 0.100" (2.54mm) pitch, through-hole mounting, and PC pin termination as the original KAJ03TAGT. No PCB modifications are required for pin compatibility.

Q: What is the difference between beryllium copper and copper alloy contacts? A: Beryllium copper contacts provide superior electrical conductivity, lower contact resistance, and extended mechanical and electrical life compared to standard copper alloy contacts. This represents an improvement over the original specification.

Q: Are both substitute parts RoHS3 compliant? A: Yes. Both the 209-3LPST and SD03H0B are ROHS3 compliant with MSL rating 1 (Unlimited), matching the compliance profile of the original KAJ03TAGT.

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