SMAZ18-13 Equivalent & Substitute Parts

Part Overview

The SMAZ18-13 is a Zener diode rated at 18 V nominal voltage with 1 W maximum power dissipation in a Surface Mount SMA (DO-214AC) package. Manufactured by Diodes Incorporated, this component is designed for voltage regulation and protection applications in electronic circuits. The product status is discontinued at DiGi Electronics, necessitating identification of equivalent and substitute components that maintain functional compatibility while ensuring design continuity and supply chain availability.

Key Parameters

Parameter	Value
Voltage - Zener (Nom) (Vz)	18 V
Tolerance	±5%
Power - Max	1 W
Impedance (Max) (Zzt)	15 Ohms
Current - Reverse Leakage @ Vr	500 nA @ 13.7 V
Voltage - Forward (Vf) (Max) @ If	1.2 V @ 200 mA
Operating Temperature	-65°C ~ 150°C
Mounting Type	Surface Mount
Package / Case	DO-214AC, SMA
RoHS Status	RoHS non-compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the SMAZ18-13 is determined by strict adherence to the following electrical and mechanical parameters:

Critical Matching Parameters:

Voltage - Zener (Nom) (Vz): 18 V
Tolerance: ±5%
Package / Case: DO-214AC, SMA (Surface Mount)
Mounting Type: Surface Mount

Allowable Variation Parameters:

Power - Max: Substitute parts may equal or exceed 1 W
Impedance (Max) (Zzt): Substitute parts may equal or exceed 15 Ohms
Current - Reverse Leakage @ Vr: Substitute parts may equal or be lower than 500 nA @ 13.7 V
Operating Temperature: Substitute parts must encompass or exceed the range -65°C ~ 150°C
RoHS Status: Substitute parts may differ in compliance status

All identified substitute parts maintain the 18 V nominal zener voltage, ±5% tolerance, and DO-214AC/SMA surface mount package configuration, ensuring direct functional and mechanical compatibility.

Parameter Comparison

Parameter	SMAZ18-13 (Diodes Inc.)	1SMA4746 (Taiwan Semi.)	1SMA4746_R1_00001 (Panjit)	SMAJ4746A-TP (MCC)	SMAZ18-TP (MCC)
Voltage - Zener (Nom) (Vz)	18 V	18 V	18 V	18 V	18 V
Tolerance	±5%	±5%	±5%	±5%	±5%
Power - Max	1 W	1.25 W	1 W	1 W	1 W
Impedance (Max) (Zzt)	15 Ohms	20 Ohms	20 Ohms	20 Ohms	15 Ohms
Current - Reverse Leakage @ Vr	500 nA @ 13.7 V	1 µA @ 13.7 V	100 nA @ 13.7 V	5 µA @ 13.7 V	500 nA @ 13.7 V
Voltage - Forward (Vf) (Max) @ If	1.2 V @ 200 mA	Not specified	Not specified	1.2 V @ 100 mA	1.2 V @ 200 mA
Operating Temperature	-65°C ~ 150°C	-55°C ~ 175°C (TJ)	-55°C ~ 150°C (TJ)	-65°C ~ 150°C	-65°C ~ 150°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
Product Status	Discontinued at DiGi Electronics	Active	Active	Active	Active

Engineering Selection Recommendations

SMAZ18-TP (Micro Commercial Co) is the primary parametric equivalent. This part maintains identical electrical specifications to the SMAZ18-13, including 1 W power rating, 15 Ohms maximum impedance, and 500 nA reverse leakage current. Operating temperature range matches the original (-65°C ~ 150°C). The component is RoHS3 compliant and carries active product status with 6,984 pieces in stock. This substitute provides direct functional replacement with improved compliance status.

1SMA4746_R1_00001 (Panjit International Inc.) offers compatibility with enhanced reverse leakage performance (100 nA @ 13.7 V versus 500 nA). Power rating remains at 1 W. Operating temperature range is -55°C ~ 150°C, which covers the original specification minimum of -65°C at the upper bound. This part is RoHS3 compliant and active, with 5,028 pieces available.

1SMA4746 (Taiwan Semiconductor Corporation) provides increased power dissipation capability at 1.25 W, exceeding the original 1 W specification. Impedance is rated at 20 Ohms maximum. Operating temperature extends to 175°C. Reverse leakage is 1 µA @ 13.7 V. This part is RoHS3 compliant and active, with 60,200 pieces in stock, offering the highest inventory availability.

SMAJ4746A-TP (Micro Commercial Co) maintains 1 W power rating and 20 Ohms impedance. Reverse leakage is 5 µA @ 13.7 V, which is higher than the original specification. Operating temperature range matches the original (-65°C ~ 150°C). This part is RoHS3 compliant and active, with 2,455 pieces available.

All substitute parts are RoHS3 compliant, addressing regulatory requirements that the original discontinued part does not meet. Selection should prioritize SMAZ18-TP for direct parametric equivalence or 1SMA4746_R1_00001 for enhanced leakage performance within the original temperature specification.

Frequently Asked Questions (FAQ)

Q: Can SMAZ18-13 be directly replaced with SMAZ18-TP?

A: Yes. SMAZ18-TP is a parametric equivalent with identical electrical specifications: 18 V nominal zener voltage, ±5% tolerance, 1 W power rating, 15 Ohms maximum impedance, and 500 nA reverse leakage current. Both components use the DO-214AC (SMA) surface mount package. Operating temperature range is identical at -65°C ~ 150°C. The primary difference is RoHS3 compliance status of the substitute.

Q: What is the difference between the substitute parts in terms of power dissipation?

A: SMAZ18-TP, 1SMA4746_R1_00001, and SMAJ4746A-TP are rated at 1 W, matching the original SMAZ18-13. The 1SMA4746 from Taiwan Semiconductor Corporation is rated at 1.25 W, providing 25% additional power dissipation capability. In applications where the original 1 W rating is sufficient, all substitutes are functionally compatible. Higher power rating does not create incompatibility.

Q: Are all substitute parts in the same package?

A: Yes. All substitute parts use the DO-214AC (SMA) surface mount package, ensuring mechanical and electrical compatibility with the original SMAZ18-13. Footprint and pin configuration are identical across all listed substitutes.

Q: What is the significance of reverse leakage current differences?

A: Reverse leakage current is specified at 500 nA @ 13.7 V for the original SMAZ18-13. Substitute parts show variation: 1SMA4746_R1_00001 at 100 nA (lower), SMAZ18-TP at 500 nA (identical), 1SMA4746 at 1 µA (higher), and SMAJ4746A-TP at 5 µA (higher). Lower leakage improves circuit performance in precision applications. Higher leakage remains within acceptable limits for standard voltage regulation and protection circuits.

Q: Does operating temperature range affect substitution compatibility?

A: The original SMAZ18-13 operates from -65°C to 150°C. SMAZ18-TP and SMAJ4746A-TP match this range exactly. 1SMA4746_R1_00001 operates from -55°C to 150°C, which does not cover the -65°C minimum. 1SMA4746 operates from -55°C to 175°C. For applications requiring full -65°C operation, SMAZ18-TP or SMAJ4746A-TP are required. For applications within -55°C to 150°C, all substitutes are compatible.

Q: What is the inventory status of each substitute?

A: SMAZ18-TP has 6,984 pieces in stock. 1SMA4746_R1_00001 has 5,028 pieces. SMAJ4746A-TP has 2,455 pieces. 1SMA4746 has the highest availability at 60,200 pieces. All parts are listed as active products with new original stock.

Q: Are all substitute parts RoHS compliant?

A: Yes. All four substitute parts are RoHS3 compliant. The original SMAZ18-13 is RoHS non-compliant. Substitution provides regulatory compliance improvement for new designs or product updates.

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