UDZ3V9B-7 Equivalent & Substitute Parts

Part Overview

The UDZ3V9B-7 is a Zener diode manufactured by Diodes Incorporated, rated at 4.03 V nominal with 200 mW power dissipation in a surface mount SOD-323 package. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing design requirements and production continuity. Substitute parts must maintain functional compatibility within the specified electrical and mechanical parameters while accommodating minor variations in voltage tolerance, power rating, and impedance characteristics.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	4.03	V
Tolerance	±3.35%	—
Power - Max	200	mW
Impedance (Max)	100	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 1 V
Operating Temperature	-65 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SC-76, SOD-323	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the UDZ3V9B-7 is determined by the following critical parameters:

Primary Substitution Criteria:

Zener voltage nominal value within acceptable circuit tolerance
Power dissipation rating equal to or greater than 200 mW
Surface mount SOD-323 package compatibility
Operating temperature range encompassing -65°C to 150°C
RoHS3 compliance and MSL 1 rating

Secondary Compatibility Factors:

Impedance (Zzt) maximum value
Reverse leakage current characteristics
Voltage tolerance specification

Substitute parts identified in this reference maintain the SOD-323 package form factor and surface mount mounting type. Zener voltage values cluster around 3.9 V nominal, representing a 3.4% deviation from the original 4.03 V specification. This variation falls within typical circuit design margins for voltage regulation and protection applications. Power ratings range from 200 mW to 300 mW, with higher ratings providing enhanced thermal margin. All listed substitutes maintain ROHS3 compliance and MSL 1 moisture sensitivity classification.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Leakage @ Vr	Temp Range	Status
UDZ3V9B-7	Diodes Incorporated	4.03 V	±3.35%	200 mW	100 Ω	5 µA @ 1 V	-65 to 150°C	Obsolete
GDZ3V9B-E3-08	Vishay General Semiconductor	3.9 V	±2%	200 mW	100 Ω	5 µA @ 1 V	-55 to 150°C	Active
SZMM3Z3V9ST1G	onsemi	3.9 V	±3%	300 mW	90 Ω	3 µA @ 1 V	-65 to 150°C	Active
CMDZ3L9 TR PBFREE	Central Semiconductor Corp	3.9 V	±5%	250 mW	900 Ω	5 µA @ 1 V	-65 to 150°C	Active
CZRV5228B-G	Comchip Technology	3.9 V	±5%	200 mW	23 Ω	10 µA @ 1 V	-60 to 150°C	Active
MM3Z3V9T1G	onsemi	3.9 V	±5%	300 mW	90 Ω	3 µA @ 1 V	-65 to 150°C	Active

Engineering Selection Recommendations

GDZ3V9B-E3-08 (Vishay General Semiconductor) provides the closest electrical match to the UDZ3V9B-7, with identical 200 mW power rating, 100 Ω impedance, and 5 µA reverse leakage specification. The ±2% tolerance represents improved voltage accuracy compared to the original ±3.35% specification. Operating temperature range extends to -55°C minimum, which is 10°C higher than the original specification. This part is active and ROHS3 compliant.

SZMM3Z3V9ST1G and MM3Z3V9T1G (both onsemi) offer enhanced power dissipation at 300 mW with reduced impedance (90 Ω) and lower reverse leakage (3 µA). Both parts maintain the full -65°C to 150°C operating range. SZMM3Z3V9ST1G carries AEC-Q101 automotive qualification. These parts are suitable for applications requiring improved thermal performance.

CMDZ3L9 TR PBFREE (Central Semiconductor Corp) provides 250 mW power rating with the full -65°C to 150°C temperature range. Impedance specification of 900 Ω represents a significant deviation from the original 100 Ω value and may affect circuit performance in voltage regulation applications requiring low dynamic impedance.

CZRV5228B-G (Comchip Technology) maintains the 200 mW power rating with notably lower impedance (23 Ω), providing superior high-frequency performance. Operating temperature minimum of -60°C is 5°C higher than the original specification. Reverse leakage of 10 µA is elevated compared to the original 5 µA specification.

All substitute parts maintain SOD-323 package compatibility, surface mount mounting type, ROHS3 compliance, and MSL 1 moisture sensitivity classification.

Frequently Asked Questions (FAQ)

Q: Can the GDZ3V9B-E3-08 directly replace the UDZ3V9B-7 in all applications?

A: The GDZ3V9B-E3-08 is electrically compatible for most applications, with matching power rating and impedance. The 3.4% lower nominal voltage (3.9 V vs. 4.03 V) and improved tolerance (±2% vs. ±3.35%) are generally acceptable in voltage regulation and protection circuits. The operating temperature minimum of -55°C (versus -65°C) may be a constraint in extreme cold environments.

Q: What is the significance of impedance variation among substitute parts?

A: Impedance (Zzt) affects dynamic voltage regulation and high-frequency response. The original UDZ3V9B-7 specifies 100 Ω maximum impedance. CZRV5228B-G (23 Ω) provides superior high-frequency performance, while CMDZ3L9 TR PBFREE (900 Ω) exhibits significantly higher impedance and may introduce voltage ripple in sensitive applications. Selection depends on circuit bandwidth requirements.

Q: Are all substitute parts available in the same packaging format?

A: All listed substitute parts use the SOD-323 surface mount package (SC-76 case designation). Packaging format differences exist in tape configuration: GDZ3V9B-E3-08, SZMM3Z3V9ST1G, CMDZ3L9 TR PBFREE, and CZRV5228B-G are supplied in Tape & Reel (TR) format, while MM3Z3V9T1G is available in Cut Tape (CT) and Digi-Reel® format. Both formats are compatible with standard pick-and-place assembly equipment.

Q: Which substitute part offers the best thermal performance?

A: SZMM3Z3V9ST1G and MM3Z3V9T1G both provide 300 mW power dissipation, representing a 50% increase over the original 200 mW rating. This enhanced power handling reduces junction temperature rise in high-current applications. Both parts maintain the full -65°C to 150°C operating range.

Q: What compliance certifications apply to all substitute parts?

A: All substitute parts listed are ROHS3 compliant and carry MSL 1 (Unlimited) moisture sensitivity classification. SZMM3Z3V9ST1G additionally carries AEC-Q101 automotive qualification. All parts are REACH unaffected and classified under ECCN EAR99 for export control purposes.

Q: How does voltage tolerance affect circuit design?

A: The original UDZ3V9B-7 specifies ±3.35% tolerance, resulting in a voltage range of 3.89 V to 4.17 V. Substitute parts with ±2% tolerance (GDZ3V9B-E3-08) narrow this range to 3.82 V to 3.98 V, improving regulation accuracy. Parts with ±5% tolerance (CMDZ3L9, CZRV5228B-G, MM3Z3V9T1G) expand the range to 3.71 V to 4.10 V, requiring circuit design verification for acceptable performance margins.

Q: Is the 3.9 V nominal voltage of substitute parts acceptable for 4.03 V applications?

A: The 3.4% voltage reduction from 4.03 V to 3.9 V is within typical design margins for voltage regulation and overvoltage protection circuits. Circuit validation is required to confirm acceptable performance. Applications with tight voltage specifications may require design modification or selection of alternative parts with closer voltage matching.

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