TL494CD Equivalent & Substitute Parts

Part Overview

The TL494CD is a Buck, Push-Pull Regulator controller IC manufactured by onsemi, designed for positive output step-down and step-up/step-down DC-DC conversion applications. This device operates as a transistor driver with dual outputs and integrated dead time and frequency control features. The TL494CD is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain compatibility across supply voltage range, output configuration, topology support, and package form factor while considering product status and compliance certifications.

Key Parameters

Parameter	TL494CD
Manufacturer	onsemi
Product Status	Obsolete
Package / Case	16-SOIC (0.154", 3.90mm Width)
Voltage - Supply (Vcc/Vdd)	7V ~ 40V
Output Type	Transistor Driver
Function	Step-Down, Step-Up/Step-Down
Output Configuration	Positive
Topology	Buck, Push-Pull
Number of Outputs	2
Frequency - Switching	200kHz
Duty Cycle (Max)	48%
Operating Temperature	0°C ~ 70°C (TA)
RoHS Status	RoHS non-compliant
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitution for the TL494CD is determined by the following critical parameters:

Package Compatibility: All substitute parts must use 16-SOIC (0.154", 3.90mm Width) surface mount packaging to ensure PCB layout compatibility.

Supply Voltage Range: Substitute parts must support the 7V ~ 40V supply voltage range to function within the same power distribution architecture.

Output Configuration: All substitutes must provide positive output configuration with dual outputs (2 outputs) to maintain circuit topology compatibility.

Output Type: Substitute parts must function as transistor drivers to maintain gate drive capability for power switching elements.

Topology Support: Substitute parts must support at minimum the Buck and Push-Pull topologies required by the TL494CD application, though broader topology support does not disqualify a part.

Control Features: Dead time control and frequency control features must be present to maintain circuit regulation characteristics.

Substitute parts are grouped into two categories: direct equivalents from the same base product family (TL494 and TL594 series from Texas Instruments and onsemi) and functional alternatives that meet all electrical and mechanical compatibility criteria.

Parameter Comparison

Part Number	Manufacturer	Product Status	Vcc/Vdd (V)	Switching Freq (kHz)	Duty Cycle Max (%)	Topology	Operating Temp (°C)	RoHS Status	Package
TL494CD	onsemi	Obsolete	7 ~ 40	200	48	Buck, Push-Pull	0 ~ 70	Non-compliant	16-SOIC
TL494CDR	Texas Instruments	Active	7 ~ 40	1 ~ 300	45	Buck, Boost, Flyback, Forward, Full-Bridge, Half-Bridge, Push-Pull	0 ~ 70	ROHS3 Compliant	16-SOIC
TL494ID	Texas Instruments	Active	7 ~ 40	1 ~ 300	45	Buck, Boost, Flyback, Forward, Full-Bridge, Half-Bridge, Push-Pull	-40 ~ 85	ROHS3 Compliant	16-SOIC
TL494IDR	Texas Instruments	Active	7 ~ 40	1 ~ 300	45	Buck, Boost, Flyback, Forward, Full-Bridge, Half-Bridge, Push-Pull	-40 ~ 85	ROHS3 Compliant	16-SOIC
TL594CD	onsemi	Obsolete	7 ~ 40	300	96	Buck, Push-Pull	-40 ~ 85	Non-compliant	16-SOIC
TL594CDR	Texas Instruments	Active	7 ~ 40	1 ~ 300	97	Buck, Boost, Flyback, Forward, Full-Bridge, Half-Bridge, Push-Pull	0 ~ 70	ROHS3 Compliant	16-SOIC
TL594ID	Texas Instruments	Active	7 ~ 40	1 ~ 300	97	Buck, Boost, Flyback, Forward, Full-Bridge, Half-Bridge, Push-Pull	-40 ~ 85	ROHS3 Compliant	16-SOIC
TL594IDR	Texas Instruments	Active	7 ~ 40	1 ~ 300	97	Buck, Boost, Flyback, Forward, Full-Bridge, Half-Bridge, Push-Pull	-40 ~ 85	ROHS3 Compliant	16-SOIC
AZ494CMTR-E1	Diodes Incorporated	Active	7 ~ 36	40	N/A	Buck	-40 ~ 85	ROHS3 Compliant	16-SOIC

Engineering Selection Recommendations

Primary Substitutes (Texas Instruments TL494/TL594 Series):

TL494CDR, TL494ID, and TL494IDR from Texas Instruments are direct functional equivalents to the TL494CD. These parts maintain the same supply voltage range (7V ~ 40V), dual output configuration, and transistor driver output type. All three are active products with ROHS3 compliance, addressing the obsolescence and compliance limitations of the original TL494CD. The TL494CDR and TL494ID differ only in packaging format (Cut Tape vs. Tube), while TL494IDR offers extended operating temperature range (-40°C ~ 85°C) compared to the TL494CD (0°C ~ 70°C). The switching frequency range of 1kHz ~ 300kHz provides broader application flexibility than the fixed 200kHz of the TL494CD.

TL594CDR, TL594ID, and TL594IDR represent enhanced variants with higher maximum duty cycle (97% vs. 48%) and extended frequency capability (1kHz ~ 300kHz). These parts are suitable for applications requiring higher duty cycle operation while maintaining full topology compatibility.

Secondary Substitute (Diodes Incorporated AZ494CMTR-E1):

The AZ494CMTR-E1 is a fixed-output buck regulator with limited topology support (Buck only) and reduced maximum input voltage (36V vs. 40V). This part is not suitable for push-pull or step-up/step-down applications and should only be considered for dedicated buck converter designs with 5V fixed output requirements.

Compliance Consideration:

All Texas Instruments substitutes (TL494/TL594 series) provide ROHS3 compliance, addressing regulatory requirements for new designs. The onsemi TL594CD remains non-compliant but offers higher duty cycle capability for legacy system updates.

Frequently Asked Questions (FAQ)

Q: Can TL494CDR directly replace TL494CD in existing designs?

A: Yes. TL494CDR maintains identical supply voltage range (7V ~ 40V), output configuration, and package form factor (16-SOIC). The primary differences are active product status and ROHS3 compliance. The switching frequency range (1kHz ~ 300kHz) is broader than the fixed 200kHz specification of TL494CD, providing design flexibility without compromising compatibility.

Q: What is the difference between TL494 and TL594 series controllers?

A: Both series support identical supply voltage (7V ~ 40V) and package (16-SOIC). The TL594 series offers higher maximum duty cycle (97% vs. 45-48%) and extended operating temperature range in some variants (-40°C ~ 85°C). The TL594 is suitable for applications requiring higher duty cycle operation or broader temperature performance.

Q: Is the AZ494CMTR-E1 compatible with TL494CD applications?

A: No. The AZ494CMTR-E1 is a fixed-output buck regulator with 5V output and supports only buck topology. It cannot function as a programmable controller for push-pull or step-up/step-down topologies. This part is only suitable for dedicated 5V buck converter designs.

Q: What packaging options are available for TL494 substitutes?

A: All substitute parts use 16-SOIC (0.154", 3.90mm Width) surface mount packaging. Texas Instruments offers two packaging formats: Cut Tape (CT) & Digi-Reel® (CDR and IDR variants) and Tube (ID variant). Package selection does not affect electrical compatibility.

Q: Are there temperature range considerations when selecting a substitute?

A: Yes. The TL494CD operates 0°C ~ 70°C. Texas Instruments TL494CDR and TL594CDR maintain this range, while TL494ID, TL494IDR, TL594ID, and TL594IDR extend to -40°C ~ 85°C. Extended temperature variants are required for applications operating below 0°C or above 70°C.

Q: Does switching frequency affect substitution compatibility?

A: The TL494CD operates at fixed 200kHz. Substitute parts offer programmable frequency ranges (1kHz ~ 300kHz for TL494/TL594 series). This provides design flexibility but requires frequency setting through external components. The application circuit must accommodate the selected switching frequency.

Q: What is the compliance status of substitute parts?

A: All Texas Instruments TL494/TL594 variants are ROHS3 compliant and REACH unaffected. The onsemi TL594CD is RoHS non-compliant. For new designs requiring regulatory compliance, Texas Instruments substitutes are required.

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