KA7500B Equivalent & Substitute Parts

Part Overview

The KA7500B is a buck regulator positive output step-down DC-DC controller IC manufactured by onsemi in a 16-PDIP package. This device functions as a transistor driver for step-down voltage conversion applications with a single output phase. The KA7500B is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support, maintenance, and new production requirements where this controller remains specified.

Substiute Parts

KA7500B

onsemiIn Stock: 25315KA7500B Datasheet

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SG3524N

STMicroelectronicsIn Stock: 44642SG3524N Datasheet

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TL494CN

onsemiIn Stock: 139122TL494CN Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the KA7500B is determined by alignment across the following critical parameters:

Package Compatibility: All substitute parts must use the 16-DIP (0.300", 7.62mm) through-hole package to ensure direct PCB compatibility without layout modifications.

Output Configuration & Topology: The KA7500B is a single-output buck topology controller. Substitute parts may support extended topologies (buck, push-pull, or flyback) provided they retain positive output configuration and can operate in buck mode.

Supply Voltage Range: The KA7500B operates from 7V to 42V. Substitute parts must support a supply voltage range that encompasses or closely matches this specification.

Switching Frequency: The KA7500B supports 1kHz to 300kHz switching frequency. Substitute parts must support frequencies within or overlapping this range.

Duty Cycle: The KA7500B maximum duty cycle is 45%. Substitute parts must support duty cycles at or above this threshold.

Output Type & Control Features: The KA7500B is a transistor driver with dead time control. Substitute parts must provide equivalent transistor driver output capability and comparable control features.

Operating Temperature & Compliance: The KA7500B operates from 0°C to 70°C and is ROHS3 compliant. Substitute parts should maintain equivalent temperature ratings and compliance status.

Parameter Comparison

Engineering Selection Recommendations

TL494CN is the primary substitute for the KA7500B. Both devices are manufactured by onsemi, share identical 16-DIP packaging, and support equivalent supply voltage ranges (7V ~ 40V). The TL494CN provides extended topology support (buck and push-pull) with a higher maximum duty cycle (48% versus 45%), synchronous rectifier capability, and additional control features including frequency control. Both devices are classified as obsolete with equivalent operating temperature ranges. The TL494CN is RoHS non-compliant, whereas the KA7500B is ROHS3 compliant; this distinction must be evaluated against application requirements and regulatory constraints.

SG3524N is a secondary substitute option manufactured by STMicroelectronics. It maintains 16-DIP package compatibility and equivalent operating temperature range. The SG3524N supports a supply voltage range of 8V to 40V, which slightly narrows the lower bound compared to the KA7500B (7V minimum). The SG3524N provides extended topology support (flyback and push-pull) with dual outputs and equivalent maximum duty cycle (45%). The SG3524N is ROHS3 compliant and classified as Last Time Buy, indicating continued but limited availability. The absence of synchronous rectifier support in the SG3524N may impact efficiency in certain buck converter applications.

Selection between TL494CN and SG3524N depends on topology requirements, RoHS compliance mandates, and supply voltage specifications. For applications requiring strict buck topology operation with synchronous rectification, TL494CN is preferred. For applications permitting extended topologies with ROHS3 compliance priority, SG3524N is suitable.

Frequently Asked Questions (FAQ)

Q: Can the SG3524N directly replace the KA7500B in a buck converter circuit?

A: The SG3524N is package-compatible and functionally capable of buck converter operation. However, the SG3524N lacks synchronous rectifier support, which may reduce efficiency compared to the KA7500B. Additionally, the SG3524N supply voltage minimum is 8V versus 7V for the KA7500B; verify that your supply voltage specification does not fall below 8V.

Q: Is the TL494CN suitable for applications requiring ROHS3 compliance?

A: No. The TL494CN is RoHS non-compliant, whereas the KA7500B is ROHS3 compliant. If ROHS3 compliance is mandatory, the SG3524N is the appropriate substitute.

Q: What is the primary difference between the KA7500B and TL494CN?

A: Both devices are onsemi buck controller ICs in 16-DIP packages with equivalent supply voltage ranges. The TL494CN supports extended topologies (buck and push-pull) with dual outputs, higher maximum duty cycle (48% versus 45%), and additional frequency control features. The TL494CN is RoHS non-compliant, whereas the KA7500B is ROHS3 compliant.

Q: Can I use the SG3524N in a high-efficiency buck converter requiring synchronous rectification?

A: The SG3524N does not include synchronous rectifier support. For applications requiring synchronous rectification, the TL494CN is the appropriate choice, as it provides this capability.

Q: Are all three devices (KA7500B, SG3524N, TL494CN) pin-compatible?

A: All three devices use the 16-DIP package with identical physical dimensions (0.300", 7.62mm). However, pin-level compatibility must be verified against specific application schematics and PCB layouts, as internal functionality and pin assignments may differ between manufacturers and device variants.

Q: What is the switching frequency limitation for each device?

A: The KA7500B supports 1kHz to 300kHz. The SG3524N is fixed at 300kHz. The TL494CN is fixed at 200kHz. Verify that your application's switching frequency requirement aligns with the selected substitute.

Q: Which substitute offers the best availability?

A: The TL494CN has the highest reported inventory (139,100 pcs), followed by the SG3524N (44,600 pcs). Both exceed typical component availability thresholds for production applications.