SA555DG4 Equivalent & Substitute Parts

Part Overview

The SA555DG4 is a 555 Type Timer/Oscillator (Single) IC manufactured by Texas Instruments, operating at 100kHz with an 8-SOIC surface mount package. This component is classified as Last Time Buy, indicating discontinued production with limited remaining inventory (804 pcs). Equivalent and substitute parts are necessary to ensure design continuity and long-term supply chain reliability for applications requiring timer and oscillator functionality.

Key Parameters

Parameter	SA555DG4 Specification
Manufacturer	Texas Instruments
Part Type	555 Type, Timer/Oscillator (Single)
Frequency	100kHz
Voltage Supply Range	4.5V ~ 16V
Supply Current	10 mA
Operating Temperature	-40°C ~ 85°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the SA555DG4 is determined by the following critical parameters:

Primary Compatibility Criteria:

Package type: 8-SOIC form factor (0.154", 3.90mm Width)
Mounting type: Surface Mount
Functional type: 555 Type Timer/Oscillator (Single)
Voltage supply range: Minimum 4.5V ~ 16V compatibility
Supply current: 10 mA nominal operation
RoHS3 compliance and MSL Level 1

Substitution Categories:

Direct Equivalents — Parts with identical electrical specifications (100kHz frequency, -40°C ~ 85°C operating temperature, 4.5V ~ 16V supply):

SA555DR (Texas Instruments, Active status, Cut Tape packaging)
LM555CM/NOPB (Texas Instruments, Active status, Tube packaging)
LM555CMX/NOPB (Texas Instruments, Active status, Cut Tape packaging)

Functional Equivalents with Extended Temperature Range — Parts meeting core electrical requirements with broader operating temperature specifications:

NCV1455BDR2G (onsemi, Active status, -40°C ~ 125°C)

Functional Equivalents with Restricted Temperature Range — Parts meeting core electrical requirements with narrower operating temperature specifications:

MC1455BDR2G (onsemi, Active status, -40°C ~ 85°C)
MC1455DR2G (onsemi, Active status, 0°C ~ 70°C)

Obsolete Equivalents — Parts with identical specifications but discontinued status:

SA555D (Fairchild Semiconductor, Obsolete status, 500kHz frequency variant)

Enhanced Performance Variants — Parts with superior electrical characteristics (higher frequency, lower supply current, extended voltage range):

LMC555CM/NOPB (Texas Instruments, Last Time Buy, 3MHz, 1.5V ~ 15V, 150µA)
LMC555CMX/NOPB (Texas Instruments, Active status, 3MHz, 1.5V ~ 15V, 150µA)

Parameter Comparison

Part Number	Manufacturer	Frequency	Voltage Supply	Supply Current	Operating Temp	Package	Status
SA555DG4	Texas Instruments	100kHz	4.5V ~ 16V	10 mA	-40°C ~ 85°C	8-SOIC	Last Time Buy
SA555DR	Texas Instruments	100kHz	4.5V ~ 16V	10 mA	-40°C ~ 85°C	8-SOIC	Active
LM555CM/NOPB	Texas Instruments	100kHz	4.5V ~ 16V	10 mA	0°C ~ 70°C	8-SOIC	Active
LM555CMX/NOPB	Texas Instruments	100kHz	4.5V ~ 16V	10 mA	0°C ~ 70°C	8-SOIC	Active
LMC555CM/NOPB	Texas Instruments	3MHz	1.5V ~ 15V	150µA	-40°C ~ 85°C	8-SOIC	Last Time Buy
LMC555CMX/NOPB	Texas Instruments	3MHz	1.5V ~ 15V	150µA	-40°C ~ 85°C	8-SOIC	Active
NCV1455BDR2G	onsemi	—	4.5V ~ 16V	10 mA	-40°C ~ 125°C	8-SOIC	Active
MC1455BDR2G	onsemi	—	4.5V ~ 16V	10 mA	-40°C ~ 85°C	8-SOIC	Active
MC1455DR2G	onsemi	—	4.5V ~ 16V	10 mA	0°C ~ 70°C	8-SOIC	Active
SA555D	Fairchild Semiconductor	500kHz	4.5V ~ 16V	10 mA	-40°C ~ 105°C	8-SOIC	Obsolete

Engineering Selection Recommendations

For Direct Replacement with Active Status: SA555DR is the primary recommended substitute. Manufactured by Texas Instruments with identical electrical specifications and Active product status, it provides the most direct continuity. Available inventory (125,100 pcs) ensures long-term supply availability. Packaging format (Cut Tape & Digi-Reel) differs from the original Tube packaging but maintains identical component functionality.

For Extended Temperature Range Applications: NCV1455BDR2G (onsemi) extends the operating temperature range to -40°C ~ 125°C while maintaining 4.5V ~ 16V supply compatibility and 10 mA supply current. Active status and substantial inventory (55,100 pcs) support production continuity. This option is suitable for industrial and automotive applications requiring broader thermal performance.

For Commercial Temperature Range Applications: MC1455DR2G (onsemi) operates within 0°C ~ 70°C, suitable for commercial-grade applications. Active status and high inventory (25,300 pcs) provide supply security. This variant is appropriate when extended temperature performance is not required.

For Enhanced Performance Requirements: LMC555CMX/NOPB offers superior specifications: 3MHz frequency capability, reduced supply current (150µA), and extended voltage range (1.5V ~ 15V). Active status and high inventory (31,756 pcs) support long-term availability. This option is suitable for low-power and high-frequency applications.

Avoid Obsolete Parts: SA555D (Fairchild Semiconductor) carries Obsolete status and should not be selected for new designs despite adequate inventory levels.

Frequently Asked Questions (FAQ)

Q: Can SA555DR directly replace SA555DG4 in existing designs? A: Yes. SA555DR is electrically and functionally identical with matching 100kHz frequency, 4.5V ~ 16V supply range, 10 mA supply current, and -40°C ~ 85°C operating temperature. The only difference is packaging format (Cut Tape vs. Tube), which does not affect component performance.

Q: What is the difference between LM555CM/NOPB and LM555CMX/NOPB? A: Both are 100kHz timer ICs with identical electrical specifications. LM555CMX/NOPB is supplied in Tape & Reel format with higher inventory availability (77,170 pcs vs. 2,027 pcs), while LM555CM/NOPB is supplied in Tube format. Electrical performance is identical.

Q: Why do onsemi parts (MC1455, NCV1455) not specify frequency? A: Frequency specification is not provided in the component data. These parts are functionally equivalent 555 Type timer ICs with identical package, voltage, and current specifications. Frequency performance should be confirmed through onsemi datasheets before selection.

Q: Can LMC555CM/NOPB replace SA555DG4 in all applications? A: LMC555CM/NOPB is a functional equivalent with enhanced specifications (3MHz vs. 100kHz, 150µA vs. 10 mA supply current). It is suitable for applications requiring higher frequency or lower power consumption. However, circuit design may require adjustment due to different electrical characteristics. Verify compatibility with application requirements before substitution.

Q: What is the significance of "Last Time Buy" status? A: Last Time Buy indicates the manufacturer has discontinued production with limited remaining inventory. SA555DG4 (804 pcs) and LMC555CM/NOPB (15,128 pcs) carry this status. Active-status alternatives (SA555DR, LM555CMX/NOPB, NCV1455BDR2G, MC1455BDR2G, MC1455DR2G) are recommended for new designs to ensure long-term supply continuity.

Q: Are all substitute parts RoHS3 compliant? A: Yes. All listed substitute parts maintain ROHS3 compliance and MSL Level 1 (Unlimited moisture sensitivity), matching the original SA555DG4 specifications.

Q: Does packaging format affect electrical performance? A: No. Tube, Cut Tape (CT) & Digi-Reel, and Tape & Reel (TR) packaging formats are logistics variations only. Electrical performance and component functionality remain identical across all packaging options for the same part number.

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