TL594CN Equivalent & Substitute Parts

Part Overview

The TL594CN is a Buck, Push-Pull Regulator controller IC manufactured by onsemi in the SWITCHMODE™ series. This device functions as a positive output step-down and step-up/step-down DC-DC controller with transistor driver output, designed for through-hole mounting in 16-DIP packaging. The TL594CN is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and component sourcing in legacy systems and new designs requiring compatible alternatives.

Substiute Parts

TL594CN

onsemiIn Stock: 9496TL594CN Datasheet

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AZ494AP-E1

Diodes IncorporatedIn Stock: 35472AZ494AP-E1 Datasheet

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TL494CN

onsemiIn Stock: 139122TL494CN Datasheet

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TL494IN

onsemiIn Stock: 20445TL494IN Datasheet

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TL594CN

onsemiIn Stock: 9496TL594CN Datasheet

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TL594IN

Texas InstrumentsIn Stock: 7158TL594IN Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the TL594CN is determined by the following critical parameters:

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

Electrical Compatibility: Substitute parts must support the same supply voltage range (7V ~ 40V), output configuration (positive), and core topologies (Buck and Push-Pull). The number of outputs must remain at 2 with single output phase.

Control Features: Dead Time Control and Frequency Control capabilities must be present to maintain functional equivalence in switching regulator applications.

Operating Temperature Range: Substitute parts must support the full -40°C ~ 85°C operating temperature range to ensure reliability across industrial and extended temperature applications.

The substitute parts are grouped into two categories based on functional scope and product status:

Category 1 - Direct Functional Equivalents (onsemi SWITCHMODE™ Series): TL494CN and TL494IN maintain identical topology, control features, and package specifications. These parts differ in switching frequency (200kHz vs. 300kHz) and duty cycle maximum (48% vs. 96%), which may affect application suitability depending on circuit design requirements.

Category 2 - Extended Topology Alternative (Texas Instruments TL594IN): The TL594IN from Texas Instruments expands topology support to include Boost, Flyback, Forward Converter, Full-Bridge, and Half-Bridge configurations while maintaining core Buck and Push-Pull capability. This part is Active status and RoHS3 compliant, offering broader design flexibility.

Category 3 - Fixed Output Alternative (Diodes Incorporated AZ494AP-E1): The AZ494AP-E1 represents a specialized fixed-output buck regulator with reduced output current (200mA) and fixed voltage output (4.95V). This part is suitable only for applications with fixed output voltage requirements and lower current demands.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement with Identical Specifications:

The TL494IN from onsemi provides the closest functional match to the TL594CN. Both parts maintain identical supply voltage range (7V ~ 40V), operating temperature range (-40°C ~ 85°C), package format (16-DIP), and control feature set (Dead Time Control, Frequency Control). The primary difference is switching frequency (200kHz vs. 300kHz) and duty cycle maximum (48% vs. 96%). Selection between these parts depends on circuit design requirements for switching frequency and maximum duty cycle operation. The TL494IN is classified as obsolete, consistent with the TL594CN status.

For Active Product Status with Extended Topology Support:

The TL594IN from Texas Instruments is the only active product in this substitute group, offering ROHS3 compliance and extended topology support including Boost, Flyback, Forward Converter, Full-Bridge, and Half-Bridge configurations. This part maintains the full -40°C ~ 85°C operating temperature range and 16-DIP package compatibility. The TL594IN supports a wider switching frequency range (1kHz ~ 300kHz) and higher maximum duty cycle (97%), providing greater design flexibility for new applications. However, this part lacks synchronous rectifier capability present in the TL594CN.

For RoHS Compliance Requirements:

The TL594IN (Texas Instruments) and AZ494AP-E1 (Diodes Incorporated) are the only ROHS3 compliant alternatives. The TL594IN maintains full functional equivalence with extended topology support. The AZ494AP-E1 is suitable only for fixed 4.95V output applications with 200mA maximum output current and should not be selected for general-purpose step-down/step-up-step-down applications.

For Temperature Range Constraints:

The TL494CN from onsemi has a reduced operating temperature range (0°C ~ 70°C) compared to the TL594CN (-40°C ~ 85°C). This part is unsuitable for applications requiring full industrial temperature range operation.

Frequently Asked Questions (FAQ)

Q: Can the TL494CN be used as a direct replacement for the TL594CN?

A: The TL494CN shares identical package, supply voltage range, output configuration, and control features with the TL594CN. However, the TL494CN operates at 200kHz switching frequency with 48% maximum duty cycle, compared to the TL594CN's 300kHz and 96% specifications. Additionally, the TL494CN has a reduced operating temperature range (0°C ~ 70°C vs. -40°C ~ 85°C). Selection depends on whether your circuit design can accommodate these parameter differences.

Q: Is the TL594IN from Texas Instruments a suitable replacement?

A: The TL594IN maintains package compatibility (16-DIP), supply voltage range (7V ~ 40V), and full operating temperature range (-40°C ~ 85°C). It offers extended topology support and is the only active product in this group with ROHS3 compliance. The primary limitation is the absence of synchronous rectifier capability. This part is suitable for new designs and applications where extended topology flexibility is beneficial.

Q: Why is the AZ494AP-E1 listed as a substitute if it has fixed output voltage?

A: The AZ494AP-E1 is included as a substitute for applications with specific fixed 4.95V output voltage requirements and 200mA maximum output current. This part is not suitable for general-purpose step-down/step-up-step-down applications requiring programmable or variable output voltage. Selection of this part should be limited to designs where fixed output specifications match application requirements.

Q: What are the key differences between onsemi and Texas Instruments versions?

A: The onsemi TL494CN and TL494IN maintain identical topology and control features but differ in switching frequency and duty cycle specifications. The Texas Instruments TL594IN expands topology support to include Boost, Flyback, Forward Converter, Full-Bridge, and Half-Bridge configurations, offering greater design flexibility. The TL594IN is the only active product and ROHS3 compliant alternative.

Q: Are all substitute parts available in the same 16-DIP package?

A: Yes, all substitute parts listed are available in 16-DIP (0.300", 7.62mm) through-hole packaging, ensuring direct PCB compatibility without layout modifications.

Q: What should I consider when selecting between these substitutes?

A: Prioritize selection based on: (1) Product status requirements (active vs. obsolete), (2) RoHS compliance needs, (3) Operating temperature range requirements, (4) Switching frequency and duty cycle specifications for your circuit design, (5) Topology requirements (extended support in TL594IN vs. Buck/Push-Pull only in TL494 series), and (6) Synchronous rectifier capability needs.