KA555D Equivalent & Substitute Parts

Part Overview

The KA555D is a 555 Type Timer/Oscillator (Single) IC manufactured by onsemi in 8-SOIC surface mount packaging. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The KA555D operates across a supply voltage range of 4.5V to 16V with a maximum supply current of 7.5 mA and an operating temperature range of 0°C to 70°C. Identifying compatible substitutes ensures design continuity and maintains system functionality when the original part becomes unavailable.

Key Parameters

Parameter	Value
Manufacturer Part Number	KA555D
Manufacturer	onsemi
Category	Clock/Timing
Type	555 Type, Timer/Oscillator (Single)
Description	IC OSC SINGLE TIMER 8-SOP
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Voltage - Supply	4.5V ~ 16V
Current - Supply	7.5 mA
Operating Temperature	0°C ~ 70°C
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)
REACH Status	REACH Unaffected

Substitute Part Grouping Explanation

Substitution of the KA555D is determined by strict adherence to the following electrical and mechanical parameters:

Critical Compatibility Parameters:

Package / Case: 8-SOIC (0.154", 3.90mm Width) — all substitutes must match this footprint
Mounting Type: Surface Mount — all substitutes must be surface mount compatible
Type: 555 Type, Timer/Oscillator (Single) — functional equivalence required
Voltage - Supply: 4.5V ~ 16V — substitute must support this range or a superset
Current - Supply: substitute must not exceed system design limits
Operating Temperature: substitute must cover or exceed 0°C ~ 70°C range

Substitute parts are grouped into three categories based on their relationship to the KA555D:

Similar Parts (MC1455BDR2G, MC1455DR2G): Active production alternatives from onsemi with identical package, voltage range, and mounting type. These parts maintain full electrical compatibility within the specified parameters.

Direct Equivalents (NE555D, NE555S-13): Parts from alternative manufacturers (STMicroelectronics, Diodes Incorporated) with identical package and voltage specifications. These provide direct functional replacement with documented 555 timer architecture.

Upgrade Parts (NA555D, NA555DR, NA555S-13, SA555D, SA555DR, SA555DRG4): Parts from Texas Instruments, Diodes Incorporated, and Fairchild Semiconductor offering extended operating temperature ranges (-40°C to 85°C or -40°C to 105°C) and active product status. These provide enhanced performance characteristics while maintaining core electrical parameters.

Parameter Comparison

Part Number	Manufacturer	Package / Case	Voltage - Supply	Current - Supply	Operating Temperature	Product Status	RoHS Status
KA555D	onsemi	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	7.5 mA	0°C ~ 70°C	Obsolete	Not specified
MC1455BDR2G	onsemi	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	10 mA	-40°C ~ 85°C	Active	ROHS3 Compliant
MC1455DR2G	onsemi	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	10 mA	0°C ~ 70°C	Active	ROHS3 Compliant
NE555D	STMicroelectronics	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	10 mA	0°C ~ 70°C	Obsolete	ROHS3 Compliant
NE555S-13	Diodes Incorporated	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	13 mA	0°C ~ 70°C	Active	ROHS3 Compliant
NA555D	Texas Instruments	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	10 mA	-40°C ~ 105°C	Last Time Buy	ROHS3 Compliant
NA555DR	Texas Instruments	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	10 mA	-40°C ~ 105°C	Active	ROHS3 Compliant
NA555S-13	Diodes Incorporated	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	13 mA	-40°C ~ 105°C	Active	ROHS3 Compliant
SA555D	Fairchild Semiconductor	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	10 mA	-40°C ~ 105°C	Obsolete	ROHS3 Compliant
SA555DR	Texas Instruments	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	10 mA	-40°C ~ 85°C	Active	ROHS3 Compliant
SA555DRG4	Texas Instruments	8-SOIC (0.154", 3.90mm Width)	4.5V ~ 16V	10 mA	-40°C ~ 85°C	Obsolete	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Identical Operating Temperature Range):

MC1455DR2G is the primary recommendation for direct replacement. It maintains the 0°C to 70°C operating temperature range of the KA555D, is in active production status, and carries ROHS3 compliance. The 8-SOIC package footprint is identical, ensuring PCB compatibility without layout modifications.

For Extended Temperature Applications:

NA555DR (Texas Instruments) is recommended when extended operating temperature range (-40°C to 105°C) is required. This part is in active production status with ROHS3 compliance and provides superior temperature performance while maintaining all other electrical parameters within specification.

SA555DR (Texas Instruments) offers an alternative extended temperature option (-40°C to 85°C) with active product status and ROHS3 compliance.

For Immediate Availability:

NA555DR and SA555DR both maintain high inventory levels (43,850 and 125,100 units respectively) and active production status, ensuring long-term availability and supply chain stability.

Compliance Considerations:

All recommended substitute parts carry ROHS3 compliance certification. The KA555D's REACH Unaffected status is maintained across all substitute options. All parts are classified as EAR99 for export control purposes.

Frequently Asked Questions (FAQ)

Q: Can MC1455DR2G be used as a direct replacement for KA555D?

A: Yes. MC1455DR2G matches the KA555D in package type (8-SOIC), mounting method (surface mount), voltage range (4.5V to 16V), and operating temperature range (0°C to 70°C). The primary difference is supply current specification (10 mA versus 7.5 mA), which is acceptable in most applications as the substitute operates within the same electrical envelope.

Q: What is the difference between MC1455BDR2G and MC1455DR2G?

A: Both parts are from onsemi with identical electrical specifications. The primary difference is operating temperature range: MC1455BDR2G operates from -40°C to 85°C, while MC1455DR2G operates from 0°C to 70°C. Select MC1455DR2G for applications matching the KA555D's temperature range, or MC1455BDR2G for extended low-temperature operation.

Q: Why do some substitutes have higher supply current specifications?

A: Supply current specifications reflect maximum operating conditions. NE555S-13 and NA555S-13 specify 13 mA maximum supply current compared to 10 mA for other variants. This difference does not prevent substitution; it indicates the part may draw more current under worst-case conditions. Verify your power supply design accommodates this specification.

Q: Are all substitute parts RoHS compliant?

A: All substitute parts listed carry ROHS3 compliance certification. The KA555D does not specify RoHS status, but all alternatives meet current RoHS3 requirements, ensuring compatibility with modern manufacturing and environmental standards.

Q: What is the significance of "Last Time Buy" status for NA555D?

A: Last Time Buy status indicates Texas Instruments will accept final orders before discontinuing the part. NA555DR, also from Texas Instruments, is in active production status and is the recommended alternative for long-term designs requiring this manufacturer's 555 timer variant.

Q: Can I use parts with extended temperature ranges in place of the KA555D?

A: Yes. Parts with extended temperature ranges (such as NA555DR operating from -40°C to 105°C) are fully compatible with applications designed for the KA555D's 0°C to 70°C range. The substitute's wider temperature specification provides additional design margin without compromising performance within the original specification window.

Q: Are there any package differences between substitute parts?

A: All substitute parts use the 8-SOIC package with 0.154" width and 3.90mm body width. Packaging format (Cut Tape, Tube, or Tape & Reel) differs by supplier but does not affect electrical or mechanical compatibility. Select based on your procurement and assembly requirements.

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