TL594CDG Equivalent & Substitute Parts

Part Overview

The TL594CDG is a Buck, Push-Pull Regulator controller IC manufactured by onsemi in the SWITCHMODE™ series. This part operates as a Transistor Driver for Step-Down and Step-Up/Step-Down DC-DC conversion topologies with dual outputs and positive output configuration. The TL594CDG is classified as Obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. Substitute parts must maintain compatibility across core electrical parameters including supply voltage range, switching frequency capability, duty cycle limits, and package form factor.

Substiute Parts

TL594CDG

onsemiIn Stock: 1716TL594CDG Datasheet

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TL594CDR2G

onsemiIn Stock: 17615TL594CDR2G Datasheet

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AZ494CMTR-E1

Diodes IncorporatedIn Stock: 4557AZ494CMTR-E1 Datasheet

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TL494CD

onsemiIn Stock: 6653TL494CD Datasheet

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TL494CDR

Texas InstrumentsIn Stock: 496691TL494CDR Datasheet

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TL494ID

Texas InstrumentsIn Stock: 2163TL494ID Datasheet

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TL494IDR

Texas InstrumentsIn Stock: 215372TL494IDR Datasheet

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TL594CD

onsemiIn Stock: 1724TL594CD Datasheet

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TL594CDR

Texas InstrumentsIn Stock: 25131TL594CDR Datasheet

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TL594ID

Texas InstrumentsIn Stock: 1768TL594ID Datasheet

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TL594IDR

Texas InstrumentsIn Stock: 20232TL594IDR Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict alignment with the following core parameters:

Primary Compatibility Criteria:

• Package / Case: 16-SOIC (0.154", 3.90mm Width) — mandatory for mechanical and electrical pin compatibility
• Output Type: Transistor Driver — required for controller functionality
• Number of Outputs: 2 — functional requirement for dual-output regulation
• Voltage - Supply (Vcc/Vdd): 7V ~ 40V — supply rail compatibility
• Output Configuration: Positive — output polarity requirement
• Control Features: Dead Time Control, Frequency Control — essential control capabilities

Secondary Compatibility Criteria:

• Topology: Buck, Push-Pull, or broader topologies (Buck, Boost, Flyback, Forward Converter, Full-Bridge, Half-Bridge, Push-Pull)
• Switching Frequency: 300kHz or frequency range encompassing 300kHz
• Duty Cycle (Max): 96% or higher
• Synchronous Rectifier: Yes or No (both acceptable; affects efficiency characteristics)
• Operating Temperature: -40°C ~ 85°C or subset thereof

Substitute parts are grouped into two categories:

Category A — Direct Functional Equivalents (onsemi SWITCHMODE™ Series): TL594CDR2G, TL594CD — identical topology, frequency, and duty cycle specifications with matching control features.

Category B — Extended Topology Controllers (Texas Instruments TL494/TL594 Series): TL494CDR, TL494ID, TL494IDR, TL594CDR, TL594ID, TL594IDR — broader topology support (Buck, Boost, Flyback, Forward Converter, Full-Bridge, Half-Bridge, Push-Pull) with frequency range 1kHz ~ 300kHz and higher duty cycle capability (45% or 97%).

Category C — Fixed-Output Buck Regulator (Diodes Incorporated): AZ494CMTR-E1 — fixed 5V output, limited to Step-Down topology; substitution only for applications requiring fixed 5V regulation.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Preferred): TL594CDR2G is the primary substitute. It maintains identical electrical specifications (7V ~ 40V supply, 300kHz switching frequency, 96% maximum duty cycle, synchronous rectifier, dual outputs) and identical topology (Buck, Push-Pull). TL594CDR2G is Active status with ROHS3 compliance, providing long-term availability and regulatory alignment. Packaging is Tape & Reel (TR), suitable for automated assembly.

For Extended Topology Support: TL494IDR and TL594IDR are Active status alternatives from Texas Instruments with ROHS3 compliance. These parts support broader topology options (Buck, Boost, Flyback, Forward Converter, Full-Bridge, Half-Bridge, Push-Pull) and extended frequency range (1kHz ~ 300kHz). TL594IDR offers 97% maximum duty cycle and -40°C ~ 85°C operating temperature, matching the original part's temperature range. TL494IDR operates at 0°C ~ 70°C, which is a narrower range. Both are suitable for applications requiring topology flexibility beyond Buck and Push-Pull.

For Industrial Temperature Range: TL594IDR and TL494IDR (Texas Instruments) support -40°C ~ 85°C operating temperature. TL494CDR and TL594CDR operate at 0°C ~ 70°C and are suitable only for commercial temperature applications.

For RoHS Compliance: All Active status parts (TL594CDR2G, TL494CDR, TL494ID, TL494IDR, TL594CDR, TL594ID, TL594IDR, AZ494CMTR-E1) are ROHS3 compliant. Obsolete parts (TL594CD, TL494CD) may not meet current compliance requirements.

For Fixed 5V Output Applications: AZ494CMTR-E1 is a fixed-output Buck regulator limited to 5V, 200mA output. This part is suitable only for applications requiring fixed 5V regulation and is not a general-purpose substitute for the TL594CDG controller.

Frequently Asked Questions (FAQ)

Q: Can TL494CDR replace TL594CDG directly? A: TL494CDR is functionally compatible in 16-SOIC package with matching supply voltage (7V ~ 40V), dual outputs, and control features. However, TL494CDR has a lower maximum duty cycle (45% vs. 96%) and narrower operating temperature range (0°C ~ 70°C vs. -40°C ~ 85°C). Substitution is valid only if your application operates within these constraints.

Q: What is the difference between TL594CDR2G and TL594CDR? A: TL594CDR2G is manufactured by onsemi with identical specifications to the original TL594CDG (300kHz, 96% duty cycle, synchronous rectifier). TL594CDR is manufactured by Texas Instruments with broader topology support (Buck, Boost, Flyback, Forward Converter, Full-Bridge, Half-Bridge, Push-Pull) and extended frequency range (1kHz ~ 300kHz), but operates at 0°C ~ 70°C instead of -40°C ~ 85°C.

Q: Is AZ494CMTR-E1 a suitable substitute? A: AZ494CMTR-E1 is a fixed-output 5V Buck regulator, not a programmable controller. It is suitable only for applications requiring fixed 5V regulation at 200mA output. It cannot replace the TL594CDG in applications requiring variable output voltage or different topologies.

Q: What packaging options are available? A: All substitute parts are available in 16-SOIC (0.154", 3.90mm Width) surface mount package. Packaging variants include Cut Tape (CT) & Digi-Reel® (TL494CDR, TL494IDR, TL594CDR, TL594IDR), Tape & Reel (TR) (TL594CDR2G), and Tube (TL494ID, TL594ID). Verify packaging compatibility with your assembly process.

Q: Which substitute has the best long-term availability? A: TL494IDR and TL594IDR from Texas Instruments are Active status with high inventory levels (215,300 and 20,200 units respectively) and ROHS3 compliance, indicating strong long-term support. TL594CDR2G from onsemi is also Active with 17,545 units in stock.

Q: Can I use TL594IDR in place of TL594CDG? A: Yes. TL594IDR is functionally compatible with identical supply voltage (7V ~ 40V), dual outputs, and control features. TL594IDR offers extended frequency range (1kHz ~ 300kHz) and higher duty cycle (97% vs. 96%), plus -40°C ~ 85°C operating temperature matching the original. Packaging is 16-SOIC Tube.

Q: What is the significance of "Synchronous Rectifier: Yes" vs. "No"? A: Synchronous rectifier capability affects efficiency in buck converter designs. TL594CDG, TL594CDR2G, and TL594CD include synchronous rectifier support. Texas Instruments TL494/TL594 series parts do not include this feature. For designs optimized around synchronous rectification, onsemi parts are preferred; for designs using external rectification, Texas Instruments parts are suitable.