BZX84C24 Zener Diode Equivalent & Substitute Parts

Part Overview

The BZX84C24 is a 24 V zener diode manufactured by onsemi, rated for 350 mW power dissipation in a surface mount SOT-23-3 package. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing design requirements and procurement needs. Substitute parts must maintain electrical compatibility across voltage regulation, power handling, and thermal operating ranges while accommodating available packaging and supplier options.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	24	V
Tolerance	±5%	—
Power - Maximum	350	mW
Impedance (Maximum)	70	Ohms
Current - Reverse Leakage @ Vr	50	nA @ 16.8 V
Voltage - Forward (Maximum) @ If	900	mV @ 10 mA
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—

Substitute Part Grouping Explanation

Substitution eligibility for the BZX84C24 is determined by the following critical parameters:

Primary Matching Criteria:

Voltage - Zener (Nominal): 24 V
Package / Case: TO-236-3, SC-59, SOT-23-3 (or compatible variants)
Mounting Type: Surface Mount

Secondary Compatibility Criteria:

Power - Maximum: Equal to or greater than 350 mW
Impedance (Maximum): 70 Ohms or lower
Current - Reverse Leakage @ Vr: Specified at comparable voltage reference
Voltage - Forward (Maximum) @ If: 900 mV @ 10 mA or lower
Operating Temperature Range: Must encompass or exceed -55°C to 150°C

Tolerance Consideration:

Tolerance of ±5% or tighter is acceptable for direct substitution
Tolerance of ±6% or wider requires application-specific validation

Substitute parts are grouped into three categories based on electrical performance alignment and product status:

Category A - Direct Equivalents (Active Status): Parts matching all primary criteria with power ratings ≥350 mW and tolerance ≤±5%

Category B - Compatible Alternatives (Active Status): Parts matching primary criteria with power ratings between 225–300 mW or tolerance variations (±2%, ±3%, ±6%)

Category C - Functional Substitutes (Active Status): Parts with alternative package options (SOT-323) or modified impedance specifications that maintain 24 V zener voltage and surface mount compatibility

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Vf Max @ 10mA (mV)	Temp Range (°C)	Package	Product Status
BZX84C24	onsemi	24	±5%	350	70	900	-55 to 150	SOT-23-3	Obsolete
BZX84C24LT1G	onsemi	24	±6%	225	70	900	-65 to 150	SOT-23-3	Active
BZX84C24 TR	Central Semiconductor Corp	24	±5%	350	70	900	-65 to 150	SOT-23-3	Active
BZX84-C24,215	NXP Semiconductors	24	±5%	250	70	900	-65 to 150	TO-236-3	Active
BZX84-C24,235	Nexperia USA Inc.	24	±5%	250	70	900	-65 to 150	TO-236-3	Active
BZX84B24-7-F	Diodes Incorporated	24	±2%	300	70	900	-65 to 150	SOT-23-3	Active
BZX84C24_R1_00001	Panjit International Inc.	24	±5%	410	70	—	-55 to 150	SOT-23-3	Active
CMPZ5252B BK PBFREE	Central Semiconductor Corp	24	±5%	350	33	900	-65 to 150	SOT-23-3	Active
CMPZ5252B TR PBFREE	Central Semiconductor Corp	24	±5%	350	33	900	-65 to 150	SOT-23-3	Active
DDZX24C-7	Diodes Incorporated	24	±3%	300	35	900	-65 to 150	SOT-23-3	Active
MMBZ5252BW-7-F	Diodes Incorporated	24	±5%	200	33	900	-65 to 150	SOT-323	Active

Engineering Selection Recommendations

Primary Recommendation - Category A (Direct Equivalents):

BZX84C24 TR (Central Semiconductor Corp) and CMPZ5252B TR PBFREE (Central Semiconductor Corp) are the preferred direct substitutes. Both maintain the 24 V nominal zener voltage, ±5% tolerance, 350 mW power rating, and SOT-23-3 package. BZX84C24 TR extends the operating temperature range to -65°C to 150°C compared to the original -55°C to 150°C. CMPZ5252B TR PBFREE offers improved impedance characteristics (33 Ohms vs. 70 Ohms) while maintaining all other electrical specifications. Both parts carry active product status and RoHS3 compliance.

Secondary Recommendation - Category B (Compatible Alternatives):

BZX84B24-7-F (Diodes Incorporated) provides tighter tolerance (±2%) and 300 mW power rating in SOT-23-3 package with extended temperature range (-65°C to 150°C). This part is suitable for applications where improved voltage regulation precision is required.

DDZX24C-7 (Diodes Incorporated) offers ±3% tolerance, 300 mW power rating, and improved impedance (35 Ohms) in SOT-23-3 package. This part is appropriate for circuits requiring lower output impedance characteristics.

BZX84-C24,215 (NXP Semiconductors) and BZX84-C24,235 (Nexperia USA Inc.) provide ±5% tolerance with 250 mW power rating in TO-236-3 package. These parts carry automotive qualification (AEC-Q101) and are suitable for applications requiring automotive-grade components.

Tertiary Recommendation - Category C (Functional Substitutes):

BZX84C24LT1G (onsemi) maintains onsemi manufacturer continuity with 24 V nominal voltage and ±6% tolerance. The 225 mW power rating is lower than the original specification; this part is suitable only for applications with reduced power dissipation requirements.

MMBZ5252BW-7-F (Diodes Incorporated) provides a smaller SOT-323 package option with 200 mW power rating. This part is applicable to space-constrained designs where the reduced power rating is acceptable.

BZX84C24_R1_00001 (Panjit International Inc.) offers the highest power rating (410 mW) with ±5% tolerance in SOT-23-3 package, suitable for applications requiring enhanced thermal headroom.

Compliance and Certification: All recommended substitute parts carry RoHS3 compliance and REACH Unaffected status. NXP and Nexperia variants include AEC-Q101 automotive qualification. Selection should prioritize active product status and compliance requirements specific to the application.

Frequently Asked Questions (FAQ)

Q: Can BZX84C24LT1G replace BZX84C24 in all applications?

A: BZX84C24LT1G maintains the 24 V zener voltage and SOT-23-3 package but reduces power rating from 350 mW to 225 mW and increases tolerance from ±5% to ±6%. Substitution is valid only if the application power dissipation does not exceed 225 mW and the wider tolerance is acceptable for circuit operation.

Q: What is the difference between BZX84C24 TR and CMPZ5252B TR PBFREE?

A: Both parts maintain 24 V nominal voltage, ±5% tolerance, 350 mW power rating, and SOT-23-3 package. The primary difference is impedance: BZX84C24 TR specifies 70 Ohms maximum impedance, while CMPZ5252B TR PBFREE specifies 33 Ohms maximum impedance. Lower impedance provides improved voltage regulation characteristics. Both are active products with RoHS3 compliance.

Q: Are NXP BZX84-C24,215 and Nexperia BZX84-C24,235 interchangeable?

A: Yes, both parts are electrically equivalent with 24 V nominal voltage, ±5% tolerance, 250 mW power rating, and TO-236-3 package. Both carry AEC-Q101 automotive qualification. The primary difference is packaging format: BZX84-C24,215 is supplied in bulk, while BZX84-C24,235 is supplied in tape and reel. Selection depends on procurement and assembly requirements.

Q: Can MMBZ5252BW-7-F be used as a direct replacement for BZX84C24?

A: MMBZ5252BW-7-F maintains 24 V nominal voltage and ±5% tolerance but uses SOT-323 package instead of SOT-23-3 and reduces power rating to 200 mW. This part is suitable only for space-constrained applications where the smaller package is required and power dissipation does not exceed 200 mW. PCB layout and assembly process modifications are necessary due to package change.

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

A: Impedance (Zzt) affects zener diode voltage regulation characteristics. Lower impedance values (33–35 Ohms in CMPZ5252B and DDZX24C-7) provide better voltage stability across varying load currents compared to higher impedance values (70 Ohms in BZX84C24). Selection depends on circuit requirements for voltage regulation precision and load current variations.

Q: Which substitute parts offer the widest operating temperature range?

A: BZX84C24 TR, BZX84-C24,215, BZX84-C24,235, BZX84B24-7-F, CMPZ5252B variants, DDZX24C-7, and MMBZ5252BW-7-F all specify -65°C to 150°C operating temperature range, extending the lower limit by 10°C compared to the original BZX84C24 specification of -55°C to 150°C. BZX84C24LT1G and BZX84C24_R1_00001 maintain the original -55°C lower limit.

Q: Are all substitute parts RoHS3 compliant?

A: All active substitute parts listed carry RoHS3 compliance status. The original BZX84C24 (obsolete) does not specify RoHS status. Compliance verification is essential for applications subject to RoHS regulations.

Q: What packaging options are available for 24 V zener diodes in this comparison?

A: SOT-23-3 (TO-236-3, SC-59) is the primary package used by most substitute parts. TO-236-3 is an equivalent designation used by NXP and Nexperia. SOT-323 is available as a smaller alternative through MMBZ5252BW-7-F. All packages are surface mount types suitable for automated assembly.

Q: How does tolerance affect circuit design considerations?

A: Tolerance ranges from ±2% (BZX84B24-7-F) to ±6% (BZX84C24LT1G). Tighter tolerance (±2–3%) provides more precise voltage regulation and is preferred for applications requiring strict voltage control. Wider tolerance (±5–6%) is acceptable for general-purpose voltage regulation where ±5% or greater variation is tolerable. Circuit design should account for worst-case tolerance limits in voltage calculations.

Q: Can substitute parts with lower power ratings be used in high-power applications?

A: No. Power rating indicates maximum continuous power dissipation capability. Using parts with lower power ratings in applications exceeding their specifications results in excessive junction temperature, reduced component lifetime, and potential failure. Application power dissipation must not exceed the selected part's power rating. Higher-power alternatives such as BZX84C24_R1_00001 (410 mW) should be selected for high-power requirements.

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