Equivalent & Substitute Parts for CMZ5918B TR13

Part Overview

The CMZ5918B TR13 is a 5.1 V Zener diode rated at 500 mW, manufactured by Central Semiconductor Corp in Surface Mount SMA packaging. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Zener diodes in this voltage class are used for voltage regulation, overvoltage protection, and reference applications in electronic circuits. The 5.1 V nominal voltage with ±5% tolerance and 500 mW power rating define the baseline performance envelope for this component category.

Key Parameters

Parameter	CMZ5918B TR13	Unit
Voltage - Zener (Nom)	5.1	V
Tolerance	±5%	%
Power - Max	500	mW
Impedance (Max)	4	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 2 V
Voltage - Forward (Vf) (Max) @ If	1.5	V @ 200 mA
Operating Temperature	-65°C ~ 150°C	°C
Mounting Type	Surface Mount	—
Package / Case	DO-214AC, SMA	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the CMZ5918B TR13 is determined by the following critical parameters:

Mandatory Matching Parameters:

Voltage - Zener (Nom): 5.1 V
Mounting Type: Surface Mount
Package / Case: DO-214AC or SMA

Allowable Variation Parameters:

Tolerance: ±5% or tighter (±2%, ±10%, ±20% are acceptable if circuit design permits)
Power - Max: Equal to or greater than 500 mW
Impedance (Max): 4 Ohms or 5 Ohms
Current - Reverse Leakage @ Vr: Equal to or lower than 5 µA @ 2 V
Voltage - Forward (Vf) (Max) @ If: 1.2 V to 1.5 V @ 200 mA
Operating Temperature: Must include -65°C to 150°C range or equivalent

Substitute parts are grouped by power rating capability: 1 W, 1.5 W, and 3 W variants. All substitute parts maintain the 5.1 V nominal voltage and Surface Mount SMA/DO-214AC packaging, ensuring mechanical and electrical compatibility with the original design footprint.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Vf @ 200mA (V)	Temp Range (°C)	Product Status
CMZ5918B TR13	Central Semiconductor Corp	5.1	±5%	500	4	1.5	-65 ~ 150	Obsolete
1SMA5918BT3G	onsemi	5.1	±5%	1500	4	1.5	-65 ~ 150	Active
3SMAJ5918B-TP	Micro Commercial Co	5.1	±5%	3000	4	1.5	-55 ~ 150	Active
SMAJ5918AE3/TR13	Microchip Technology	5.1	±10%	3000	4	1.2	-65 ~ 150	Active
SMAJ5918BE3/TR13	Microchip Technology	5.1	±5%	3000	4	1.2	-65 ~ 150	Active
SMAJ5918CE3/TR13	Microchip Technology	5.1	±2%	3000	4	1.2	-65 ~ 150	Active
SMAJ5918E3/TR13	Microchip Technology	5.1	±20%	3000	4	1.2	-65 ~ 150	Active
SMAZ5V1-13-F	Diodes Incorporated	5.1	±5%	1000	5	1.2	-65 ~ 150	Active
SMAZ5V1-TP	Micro Commercial Co	5.1	±5%	1000	5	1.2	-65 ~ 150	Active
SZ1SMA5918BT3G	onsemi	5.1	±5%	1500	4	1.5	-65 ~ 150	Active

Engineering Selection Recommendations

Primary Substitutes (Direct Replacement - Active Status):

1SMA5918BT3G and SZ1SMA5918BT3G (onsemi) are functionally equivalent with 1.5 W power rating, exceeding the original 500 mW specification. Both maintain ±5% tolerance, 4 Ohms impedance, and -65°C to 150°C operating range. These parts are in active production with high inventory availability (55,400 and 25,100 units respectively). SZ1SMA5918BT3G includes AEC-Q101 automotive qualification.

Secondary Substitutes (Enhanced Performance - Active Status):

3SMAJ5918B-TP (Micro Commercial Co), SMAJ5918BE3/TR13, SMAJ5918CE3/TR13, and SMAJ5918E3/TR13 (Microchip Technology) provide 3 W power rating with identical 5.1 V nominal voltage and ±5% or tighter tolerance. SMAJ5918BE3/TR13 matches the original ±5% tolerance exactly. SMAJ5918CE3/TR13 offers ±2% tolerance for applications requiring tighter voltage regulation. All maintain 4 Ohms impedance and -65°C to 150°C operating range except 3SMAJ5918B-TP which operates to -55°C minimum.

Lower Power Alternatives (1 W Rating - Active Status):

SMAZ5V1-13-F (Diodes Incorporated) and SMAZ5V1-TP (Micro Commercial Co) provide 1 W power rating with ±5% tolerance. These are suitable for applications where the original 500 mW specification is adequate and lower power dissipation is preferred. Impedance is 5 Ohms versus 4 Ohms in the original part.

All substitute parts are RoHS3 compliant, REACH unaffected, and classified as EAR99 for export control purposes.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with higher power rating than the original 500 mW specification?

A: Yes. Higher power ratings (1 W, 1.5 W, 3 W) are direct substitutes. The higher power capability does not affect circuit operation; it only provides additional thermal margin. The component will operate at the same voltage regulation point (5.1 V nominal) and current characteristics.

Q: What is the difference between the Microchip SMAJ5918 variants (AE3, BE3, CE3, E3)?

A: The variants differ in tolerance specification: AE3 is ±10%, BE3 is ±5%, CE3 is ±2%, and E3 is ±20%. All maintain identical 5.1 V nominal voltage, 3 W power rating, and -65°C to 150°C operating range. Selection depends on circuit tolerance requirements.

Q: Are the onsemi 1SMA5918BT3G and SZ1SMA5918BT3G interchangeable?

A: Yes. Both are onsemi 5.1 V, 1.5 W Zener diodes with ±5% tolerance and identical electrical specifications. SZ1SMA5918BT3G includes AEC-Q101 automotive qualification; use this variant for automotive applications.

Q: Can I substitute a 1 W part (SMAZ5V1 series) for the original 500 mW part?

A: Yes, if circuit power dissipation does not exceed 1 W. The SMAZ5V1-13-F and SMAZ5V1-TP maintain 5.1 V nominal voltage and ±5% tolerance. Impedance is 5 Ohms versus 4 Ohms in the original, which may affect high-frequency response minimally.

Q: What is the significance of the DO-214AC and SMA package designations?

A: DO-214AC and SMA refer to the same Surface Mount package form factor. All substitute parts use this identical package, ensuring mechanical compatibility with the original PCB footprint and reflow soldering process.

Q: Why is the CMZ5918B TR13 marked as obsolete?

A: Obsolete status indicates the manufacturer has discontinued production. Active substitute parts from onsemi, Microchip Technology, Diodes Incorporated, and Micro Commercial Co provide equivalent or enhanced functionality with ongoing manufacturing support.

Q: Which substitute should I select for new designs?

A: For new designs, select from active-status parts with established supply chains. 1SMA5918BT3G or SMAJ5918BE3/TR13 are recommended for general applications. For automotive applications, specify SZ1SMA5918BT3G (AEC-Q101 qualified). For precision voltage regulation, specify SMAJ5918CE3/TR13 (±2% tolerance).

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