CLL4763A TR Zener Diode 91V 1W MELF Equivalent & Substitute Parts

Part Overview

The CLL4763A TR is a surface mount Zener diode manufactured by Central Semiconductor Corp, rated at 91 V nominal voltage with 1 W maximum power dissipation in MELF (DO-213AB) package. This component is classified as obsolete, which necessitates identification of active equivalent and substitute parts for ongoing design support and procurement continuity. Substitute parts must maintain electrical compatibility across voltage regulation, power handling, and thermal operating ranges while accommodating available packaging options.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	91	V
Tolerance	±5%	—
Power - Max	1	W
Impedance (Max)	250	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 69.2 V
Voltage - Forward (Max) @ If	1.2	V @ 200 mA
Operating Temperature Range	-65 to 200	°C
Mounting Type	Surface Mount	—
Package / Case	DO-213AB, MELF	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the CLL4763A TR is determined by strict equivalence in the following electrical parameters: nominal Zener voltage (91 V), voltage tolerance (±5%), maximum power rating (1 W minimum), impedance characteristics (250 Ohms maximum), and reverse leakage current specifications. Package compatibility is evaluated based on DO-213AB / MELF form factor or functionally equivalent surface mount packages. Operating temperature range must support the application's thermal requirements. Reverse leakage current and forward voltage characteristics are secondary selection criteria when primary parameters are matched.

Substitute parts are grouped into three categories:

Category 1: Direct Electrical Equivalents (DO-213AB / MELF Package) Parts maintaining 91 V nominal, ±5% tolerance, 1 W power rating, and identical package form factor.

Category 2: Enhanced Performance Equivalents (DO-213AB / MELF Package) Parts with 91 V nominal, ±5% tolerance, but increased power rating (1.25 W) or improved reverse leakage characteristics, maintaining DO-213AB package compatibility.

Category 3: Tolerance Variants (DO-213AB / MELF Package) Parts with 91 V nominal and DO-213AB package but differing voltage tolerance (±10%, ±20%) or power specifications.

Category 4: Package Variant (SMB Package) Parts with 91 V nominal, ±5% tolerance, and enhanced power rating (3 W) in alternative SMB (DO-214AA) surface mount package.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Ir @ Vr	Vf (Max)	Temp Range	Package	Status
CLL4763A TR	Central Semiconductor	91 V	±5%	1 W	250 Ω	5 µA @ 69.2 V	1.2 V @ 200 mA	-65 to 200°C	DO-213AB MELF	Obsolete
1N4763AUR	Microchip Technology	91 V	±5%	1 W	250 Ω	5 µA @ 69.2 V	1.2 V @ 200 mA	-65 to 175°C	DO-213AB MELF	Active
1N3043BUR-1	Microchip Technology	91 V	±5%	1 W	250 Ω	10 µA @ 69.2 V	1.2 V @ 200 mA	-55 to 175°C	DO-213AB MELF	Active
1N5948BUR-1	Microchip Technology	91 V	±5%	1.25 W	200 Ω	1 µA @ 69.2 V	1.2 V @ 200 mA	-65 to 175°C	DO-213AB MELF	Active
1SMB5948BT3G	onsemi	91 V	±5%	3 W	200 Ω	1 µA @ 69.2 V	1.5 V @ 200 mA	-65 to 150°C	DO-214AA SMB	Active
CDLL3043	Microchip Technology	91 V	±20%	1 W	250 Ω	500 nA @ 69.2 V	1.2 V @ 200 mA	-55 to 175°C	DO-213AB MELF	Active
CDLL3043A	Microchip Technology	91 V	±10%	1 W	250 Ω	500 nA @ 69.2 V	1.2 V @ 200 mA	-55 to 175°C	DO-213AB MELF	Active
CDLL3043B	Microchip Technology	91 V	±5%	1 W	250 Ω	500 nA @ 69.2 V	1.2 V @ 200 mA	-55 to 175°C	DO-213AB MELF	Active
CDLL4763	Microchip Technology	91 V	±10%	Not specified	250 Ω	100 nA @ 69.2 V	1.2 V @ 200 mA	-65 to 175°C	DO-213AB MELF	Active
CDLL4763A	Microchip Technology	91 V	±5%	Not specified	250 Ω	100 nA @ 69.2 V	1.2 V @ 200 mA	-65 to 175°C	DO-213AB MELF	Active
CDLL5948B	Microchip Technology	91 V	±5%	1.25 W	200 Ω	1 µA @ 69.2 V	1.2 V @ 200 mA	-65 to 175°C	DO-213AB MELF	Active

Engineering Selection Recommendations

Primary Selection: 1N4763AUR (Microchip Technology)

The 1N4763AUR provides direct electrical and package equivalence to the obsolete CLL4763A TR. All critical parameters match: 91 V nominal voltage, ±5% tolerance, 1 W power rating, 250 Ohms impedance, and DO-213AB MELF package. The part is in active production status. Operating temperature range is -65 to 175°C, which covers the lower end of the original specification (-65 to 200°C). This part is suitable for applications where the upper temperature limit of 175°C is acceptable.

Secondary Selection: CDLL3043B (Microchip Technology)

The CDLL3043B matches the CLL4763A TR in voltage (91 V), tolerance (±5%), power (1 W), impedance (250 Ohms), and package (DO-213AB MELF). This part is in active production. Operating temperature range is -55 to 175°C. The reverse leakage current is significantly lower (500 nA versus 5 µA), which may provide improved performance in low-current applications. This part is suitable when the lower temperature limit of -55°C is acceptable.

Enhanced Performance Option: CDLL5948B (Microchip Technology)

The CDLL5948B maintains 91 V nominal, ±5% tolerance, and DO-213AB MELF package but offers increased power rating (1.25 W versus 1 W) and lower impedance (200 Ohms versus 250 Ohms). Operating temperature range is -65 to 175°C. This part is suitable for applications requiring higher power dissipation capability or improved impedance characteristics while maintaining package compatibility.

Higher Power Alternative: 1SMB5948BT3G (onsemi)

The 1SMB5948BT3G provides 91 V nominal, ±5% tolerance, and significantly increased power rating (3 W). Package is DO-214AA SMB, which is larger than MELF. This part is in active production with RoHS3 compliance. Operating temperature range is -65 to 150°C. This part is suitable for applications requiring substantially higher power dissipation where PCB layout can accommodate the larger SMB package.

Tolerance Variants: CDLL3043, CDLL3043A, CDLL4763, CDLL4763A (Microchip Technology)

These parts offer alternative voltage tolerances (±20%, ±10%) or unspecified power ratings. Selection depends on application tolerance requirements. CDLL3043 and CDLL3043A feature significantly lower reverse leakage (500 nA). CDLL4763 and CDLL4763A feature even lower reverse leakage (100 nA). All are in active production and DO-213AB MELF package.

Frequently Asked Questions (FAQ)

Q1: Can I use 1N4763AUR as a direct replacement for CLL4763A TR?

Yes. The 1N4763AUR is electrically and mechanically equivalent. Both parts have 91 V nominal voltage, ±5% tolerance, 1 W power rating, 250 Ohms impedance, and DO-213AB MELF package. The primary difference is operating temperature range: 1N4763AUR is rated -65 to 175°C versus the original -65 to 200°C. If your application operates below 175°C, this part is a direct substitute.

Q2: What is the difference between CDLL3043B and 1N4763AUR?

Both parts have identical electrical specifications (91 V, ±5%, 1 W, 250 Ohms, DO-213AB MELF). The key difference is reverse leakage current: CDLL3043B is 500 nA at 69.2 V, while 1N4763AUR is 5 µA at 69.2 V. CDLL3043B has lower leakage, which may be beneficial in precision voltage regulation circuits. Operating temperature ranges differ: CDLL3043B is -55 to 175°C, while 1N4763AUR is -65 to 175°C.

Q3: Why would I choose CDLL5948B over 1N4763AUR?

CDLL5948B offers higher power rating (1.25 W versus 1 W) and lower impedance (200 Ohms versus 250 Ohms). Both maintain 91 V nominal, ±5% tolerance, and DO-213AB MELF package. Choose CDLL5948B if your circuit requires higher power dissipation capability or if lower impedance improves regulation performance. Operating temperature range is identical (-65 to 175°C).

Q4: Can I use the SMB package 1SMB5948BT3G instead of MELF?

Yes, electrically. The 1SMB5948BT3G maintains 91 V nominal and ±5% tolerance. However, the SMB package (DO-214AA) is physically larger than MELF (DO-213AB). PCB layout must accommodate the larger footprint. The 1SMB5948BT3G offers 3 W power rating versus 1 W, providing significantly higher power handling. Operating temperature range is -65 to 150°C, which is lower than the original specification. Use this part only if PCB space permits and the 150°C upper temperature limit is acceptable.

Q5: What does voltage tolerance mean for Zener diode selection?

Voltage tolerance specifies the acceptable range around the nominal 91 V rating. The CLL4763A TR has ±5% tolerance, meaning the actual Zener voltage can be 86.45 V to 95.55 V. Parts with ±10% tolerance (CDLL3043A, CDLL4763) have wider ranges (81.9 V to 100.1 V). Parts with ±20% tolerance (CDLL3043) have even wider ranges (72.8 V to 109.2 V). Select tolerance based on your circuit's voltage regulation requirements. Tighter tolerance (±5%) is required for precision applications.

Q6: Why is reverse leakage current important?

Reverse leakage current is the small current flowing through the Zener diode when reverse-biased below the Zener voltage. Lower leakage current (500 nA in CDLL3043B versus 5 µA in 1N4763AUR) reduces power consumption and improves circuit performance in low-current or precision applications. Higher leakage current may be acceptable in high-current power supply applications where the leakage is negligible compared to load current.

Q7: What is impedance (Zzt) and why does it matter?

Impedance (Zzt) is the dynamic impedance of the Zener diode at the test current. Lower impedance (200 Ohms in CDLL5948B versus 250 Ohms in CLL4763A TR) provides better voltage regulation and lower output impedance. For most applications, the difference between 200 and 250 Ohms is negligible. Select lower impedance if your circuit requires superior voltage regulation performance.

Q8: Can I use a part with lower operating temperature range?

Only if your application does not require the full temperature range. For example, CDLL3043B is rated -55 to 175°C, while CLL4763A TR is -65 to 200°C. If your circuit operates between -55 and 175°C, CDLL3043B is acceptable. If your circuit requires operation below -55°C or above 175°C, you must select a part with a wider temperature range.

Q9: What does "Active" product status mean?

Active status indicates the part is currently manufactured and available from the supplier. The CLL4763A TR is obsolete, meaning it is no longer manufactured. All substitute parts listed are in active production, ensuring long-term availability and supply chain continuity.

Q10: Are there any compliance differences between substitute parts?

Yes. The 1SMB5948BT3G is RoHS3 compliant, while most other parts are RoHS non-compliant. If your application requires RoHS compliance, the 1SMB5948BT3G is the only option among the listed substitutes. All parts are REACH unaffected and classified as EAR99 for export control purposes.

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