KA78L09AZBU Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The KA78L09AZBU is a linear voltage regulator IC manufactured by onsemi, designed to provide a fixed positive 9V output at 100mA. This device operates across an input voltage range up to 30V and includes integrated over-temperature and short-circuit protection. The part is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain identical electrical specifications and mechanical compatibility while preferably offering active product status and improved compliance certifications.

Substiute Parts

KA78L09AZBU

onsemiIn Stock: 818KA78L09AZBU Datasheet

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MC78L09ABPRAG

onsemiIn Stock: 4925MC78L09ABPRAG Datasheet

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MC78L09ABPRPG

onsemiIn Stock: 1266MC78L09ABPRPG Datasheet

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MC78L09ACPG

onsemiIn Stock: 1980MC78L09ACPG Datasheet

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L78L09ABZ

STMicroelectronicsIn Stock: 2509L78L09ABZ Datasheet

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UA78L09ACLP

Texas InstrumentsIn Stock: 1356UA78L09ACLP Datasheet

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UA78L09ACLPE3

Texas InstrumentsIn Stock: 4598UA78L09ACLPE3 Datasheet

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UA78L09ACLPR

Texas InstrumentsIn Stock: 6065UA78L09ACLPR Datasheet

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UA78L09ACLPRE3

Texas InstrumentsIn Stock: 4372UA78L09ACLPRE3 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the KA78L09AZBU is determined by the following critical parameters:

• Output Voltage: Must be fixed at 9V
• Output Current: Must support 100mA minimum
• Input Voltage Range: Must accept up to 24V minimum (30V preferred)
• Package: Must be TO-92-3 or equivalent TO-226 variant
• Mounting: Must be Through Hole
• Protection: Must include Over Temperature and Short Circuit protection

Substitute parts are grouped by manufacturer and product status. Parts meeting all electrical and mechanical criteria are considered direct equivalents. Variations in quiescent current (5.5mA to 6mA), PSRR performance (44dB to 57dB), and input voltage maximum (24V vs 30V) do not disqualify substitution but are noted for system-level design considerations.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Active Status, Full Compatibility)

MC78L09ABPRAG and MC78L09ABPRPG from onsemi are the preferred substitutes. Both maintain the same manufacturer lineage as the original KA78L09AZBU, support the full 30V input range, and are in active production status. MC78L09ABPRAG offers improved PSRR performance (57dB vs 44dB) and is available in higher inventory quantities (4885 pcs). Both parts are ROHS3 compliant.

L78L09ABZ from STMicroelectronics is a direct electrical equivalent with active product status, matching the original -40°C to 125°C operating range and 30V input maximum. This part maintains identical PSRR performance (44dB) and offers the same TO-92-3 package configuration. Inventory availability is substantial (2400 pcs).

Secondary Substitutes (Active Status, Input Voltage Limitation)

UA78L09ACLPR and UA78L09ACLPRE3 from Texas Instruments are active production parts with full TO-92-3 package compatibility. These parts operate with a maximum input voltage of 24V (versus 30V for the original), which limits their use to applications where input voltage does not exceed 24V. Both include reverse polarity protection in addition to over-temperature and short-circuit protection. ROHS3 compliance is confirmed.

Not Recommended for New Designs

UA78L09ACLP and UA78L09ACLPE3 carry Last Time Buy status, indicating discontinued production. These parts should not be selected for new designs requiring long-term supply assurance.

MC78L09ACPG has a reduced operating temperature minimum of 0°C (versus -40°C for the original), making it unsuitable for applications requiring full military or extended temperature range operation.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with a lower maximum input voltage (24V vs 30V)?

A: Only if your circuit design ensures input voltage never exceeds 24V. The UA78L09ACLPR and UA78L09ACLPRE3 are rated for 24V maximum input. Exceeding this rating will damage the device. Verify your power supply and input protection circuits before selecting these parts.

Q: What is the difference between TO-92 and TO-92-3 packages?

A: Both designations refer to the same three-lead through-hole package (TO-226). The suffix "-3" explicitly indicates three leads. All substitute parts listed are mechanically compatible with the original KA78L09AZBU TO-92-3 footprint.

Q: Why do some substitutes have higher PSRR values?

A: PSRR (Power Supply Rejection Ratio) measures how effectively the regulator rejects input voltage ripple. Higher PSRR values (57dB vs 44dB) indicate better noise rejection. This is a performance improvement and does not affect basic substitution compatibility. Applications sensitive to supply noise may benefit from higher PSRR parts.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All active production substitutes listed (MC78L09ABPRAG, MC78L09ABPRPG, MC78L09ACPG, L78L09ABZ, UA78L09ACLPR, UA78L09ACLPRE3) are ROHS3 compliant. The original KA78L09AZBU does not carry ROHS certification.

Q: Which substitute offers the best long-term availability?

A: MC78L09ABPRAG and L78L09ABZ are recommended for long-term designs. Both are in active production status with substantial inventory levels (4885 pcs and 2400 pcs respectively) and full compliance certifications.

Q: Can I use these parts interchangeably on the same PCB?

A: Yes, all listed substitutes use the same TO-92-3 through-hole package and pin configuration. Direct board-level substitution is possible without layout modifications. Verify that your circuit input voltage does not exceed 24V if using Texas Instruments parts.