CZRT55C30-G Zener Diode 30V 350mW SOT-23-3 Equivalent & Substitute Parts

Part Overview

The CZRT55C30-G is a 30V Zener diode manufactured by Comchip Technology, rated for 350mW power dissipation in a surface mount SOT-23-3 package. This component is classified as Active product status with full RoHS3 compliance and REACH unaffected designation. Equivalent and substitute parts are identified based on matching nominal Zener voltage (30V), compatible package geometry (SOT-23-3/TO-236-3), surface mount technology, and operating temperature range. Alternative sources become necessary for supply chain optimization, inventory availability, or design flexibility across multiple qualified manufacturers.

Key Parameters

Parameter	Value	Unit	Significance for Substitution
Voltage - Zener (Nom)	30	V	Primary selection criterion; must match exactly
Power - Max	350	mW	Thermal rating; substitutes may vary ±50mW
Tolerance	±7%	%	Voltage accuracy; tighter tolerances acceptable
Package / Case	SOT-23-3 (TO-236-3, SC-59)	—	Physical footprint; must be identical
Mounting Type	Surface Mount	—	Assembly compatibility; must remain surface mount
Operating Temperature	-65°C to 150°C	°C	Thermal range; substitutes must cover or exceed
Impedance (Max)	80	Ohms	Dynamic resistance; affects circuit performance
Current - Reverse Leakage @ Vr	100	nA @ 21V	Leakage specification; lower values acceptable
Voltage - Forward (Vf) (Max) @ If	900	mV @ 10mA	Forward bias characteristic; must match
RoHS Status	ROHS3 Compliant	—	Regulatory requirement; all substitutes must comply

Substitute Part Grouping Explanation

Substitution logic for the CZRT55C30-G is based on the following mandatory alignment criteria:

Primary Criteria (Non-Negotiable):

Nominal Zener voltage: 30V (exact match required)
Package type: SOT-23-3 / TO-236-3 / SC-59 (identical footprint)
Mounting technology: Surface Mount
Operating temperature range: -65°C to 150°C minimum
RoHS3 compliance and REACH unaffected status

Secondary Criteria (Allowable Variation):

Power rating: 300mW to 350mW (substitutes rated 300mW are acceptable for 350mW applications with thermal margin verification)
Tolerance: ±2% to ±7% (tighter tolerances are acceptable upgrades)
Impedance: 49 to 80 Ohms (lower impedance values provide improved performance)
Reverse leakage: 50nA to 100nA (lower leakage is acceptable)

All identified substitutes meet the primary criteria. Variations in secondary parameters reflect different manufacturer specifications while maintaining functional equivalence in standard 30V Zener diode applications.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power Max	Impedance Max	Reverse Leakage @ Vr	Temp Range	Package	Inventory
CZRT55C30-G	Comchip Technology	30V	±7%	350mW	80Ω	100nA @ 21V	-65°C to 150°C	SOT-23-3	923 Pcs
BZX84B30-7-F	Diodes Incorporated	30V	±2%	300mW	80Ω	100nA @ 21V	-65°C to 150°C	SOT-23-3	9735 Pcs
BZX84B30Q-7-F	Diodes Incorporated	30V	±2%	300mW	80Ω	100nA @ 21V	-65°C to 150°C	SOT-23-3	2355 Pcs
BZX84C30-7-F	Diodes Incorporated	30V	±7%	300mW	80Ω	100nA @ 21V	-65°C to 150°C	SOT-23-3	21200 Pcs
BZX84C30-TP	Micro Commercial Co	30V	±5%	350mW	80Ω	100nA @ 21V	-55°C to 150°C	SOT-23-3	2766 Pcs
DDZX30D-13	Diodes Incorporated	30V	±3%	300mW	55Ω	50nA @ 23V	-65°C to 150°C	SOT-23-3	999 Pcs
DDZX30D-7	Diodes Incorporated	30V	±3%	300mW	55Ω	50nA @ 23V	-65°C to 150°C	SOT-23-3	206894 Pcs
MMBZ5256B-7-F	Diodes Incorporated	30V	±5%	350mW	49Ω	100nA @ 23V	-65°C to 150°C	SOT-23-3	3200 Pcs

Engineering Selection Recommendations

Direct Equivalents (Identical Specifications):

BZX84C30-7-F from Diodes Incorporated provides the closest functional match with identical tolerance (±7%), impedance (80Ω), and reverse leakage characteristics. This part maintains full compatibility with the original CZRT55C30-G design while offering significantly higher inventory availability (21200 units). Both parts carry RoHS3 compliance and unlimited moisture sensitivity level (MSL 1).

Enhanced Performance Alternatives:

DDZX30D-7 and DDZX30D-13 offer improved electrical characteristics with reduced impedance (55Ω vs 80Ω) and lower reverse leakage (50nA vs 100nA). These parts are suitable for applications requiring tighter voltage regulation. DDZX30D-7 provides exceptional inventory depth (206894 units) with ±3% tolerance. Both maintain the full -65°C to 150°C operating range.

Higher Power Rating Options:

MMBZ5256B-7-F and BZX84C30-TP both maintain the 350mW power rating of the original part. MMBZ5256B-7-F features superior impedance performance (49Ω) with ±5% tolerance. BZX84C30-TP from Micro Commercial Co provides identical power and tolerance specifications but operates from -55°C (reduced low-temperature range).

Tolerance-Optimized Selection:

BZX84B30-7-F and BZX84B30Q-7-F both provide ±2% tolerance, representing tighter voltage accuracy than the original ±7% specification. BZX84B30Q-7-F carries AEC-Q101 automotive qualification for applications requiring automotive-grade reliability. Both are rated 300mW with 80Ω impedance.

All recommended substitutes maintain RoHS3 compliance, REACH unaffected status, and surface mount SOT-23-3 package compatibility. Selection should be based on specific application requirements for power dissipation, voltage tolerance, and operating temperature extremes.

Frequently Asked Questions (FAQ)

Q: Can BZX84B30-7-F (300mW) replace CZRT55C30-G (350mW) in my circuit?

A: Yes, provided the circuit design includes adequate thermal margin. The 300mW rating is acceptable for applications where actual power dissipation remains below 300mW. Verify your circuit's maximum Zener current and power calculation before substitution. If the design requires full 350mW capability, select MMBZ5256B-7-F or BZX84C30-TP instead.

Q: What is the difference between BZX84B30Q-7-F and BZX84B30-7-F?

A: Both parts are electrically identical (30V, ±2%, 300mW, SOT-23-3). BZX84B30Q-7-F carries AEC-Q101 automotive qualification and is tested to automotive reliability standards. Select BZX84B30Q-7-F for automotive or mission-critical applications; BZX84B30-7-F is suitable for general industrial and consumer applications.

Q: Why do DDZX30D-7 and DDZX30D-13 have lower impedance (55Ω vs 80Ω)?

A: Lower impedance indicates better voltage regulation performance and reduced dynamic resistance. This characteristic improves circuit stability under varying load conditions. Both parts are direct substitutes; the lower impedance represents an enhancement rather than a limitation. Select these parts when improved voltage regulation is beneficial.

Q: Is BZX84C30-TP compatible with designs requiring -65°C operation?

A: No. BZX84C30-TP operates from -55°C to 150°C, which does not meet the -65°C minimum of the original CZRT55C30-G. Use this part only in applications with minimum operating temperature of -55°C or higher. For full -65°C to 150°C range compatibility, select BZX84B30-7-F, BZX84C30-7-F, DDZX30D-7, DDZX30D-13, or MMBZ5256B-7-F.

Q: Can I use DDZX30D-7 in high-volume production given its large inventory?

A: Yes. DDZX30D-7 offers 206894 units in stock, providing supply security for high-volume applications. The part meets all primary substitution criteria with enhanced electrical performance (±3% tolerance, 55Ω impedance, 50nA leakage). Verify design compatibility with the improved specifications before full production transition.

Q: What packaging options are available for these substitutes?

A: All identified substitutes use SOT-23-3 (also designated TO-236-3 or SC-59) surface mount package with identical footprint and pinout. BZX84C30-7-F is available in Cut Tape (CT) and Digi-Reel packaging; all others are supplied in Tape & Reel (TR) format. Confirm packaging format with your procurement requirements.

Q: Are all substitutes RoHS3 compliant?

A: Yes. All identified substitute parts carry RoHS3 compliance and REACH unaffected status, matching the regulatory profile of the original CZRT55C30-G. No additional compliance verification is required for substitution.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message