ICBOMS
RFQ

TL494CDR

Texas Instruments

Texas Instruments TL494CDR, PWM controller, 7 V to 40 V supply, 1 kHz to 300 kHz switching, 45% max duty cycle, 2 outputs, transistor driver, 16-SOIC, active lifecycle.

Texas Instruments TL494CDR
 Download datasheet (PDF)
[IN STOCK] In Stock: 3,825 pcs
$0.38/ pc

Volume pricing

Buy Now

Subtotal:$1.90
Inquire on WhatsApp Upload full BOM

MOQ 5 · Tape & Reel (TR); Cut Tape (CT) · RoHS · EIA-481 · DAP/DDP · T/T

[ORIGINAL SEALED] [PRE-SHIP HD PHOTOS] [30D WARRANTY · COC] [TRACKED DAP/DDP]

Technical specifications

TL494CDR specifications
Parameter / AttributeSpecification / Value
Output typeTransistor Driver
MountingSurface Mount
Voltage - supply (Vcc (Vdd))7V ~ 40V
Frequency - switching1kHz ~ 300kHz
I/O channels2
Output phases1
Duty cycle45%
Operating temperature0°C~70°C(TA)
PackageTape & Reel (TR); Cut Tape (CT)
FunctionStep-Up, Step-Down, Step-Up/Step-Down
TopologyBuck, Boost, Flyback, Forward Converter, Full-Bridge, Half-Bridge, Push-Pull
Clock syncNo
Case16-SOIC (0.154\", 3.90mm Width)
Control featuresDead Time Control, Frequency Control
Output configurationPositive
Synchronous rectifierNo
100% Footprint Match · Solder-Ready (No PCB Redesign Needed)

Need Stock or a Drop-in Second-Source for TL494CDR?

Package: DIP-16 / SOIC-16 · Pin-compatible replacements with immediate Shenzhen spot stock

Footprint Match 98%
Supply Chain & Allocation Reality:

The TL494 is the PWM heart of classic ATX supplies, inverters, welders and battery chargers - a 16-pin voltage-mode controller whose real-world identity is a family: KA7500B, MB3759 and IR3M02 are pin-for-pin clones, and repair benches swap them daily. Two traps live here. The first is quality drift inside the clone family - the cheaper suffix revisions (7500C and similar) have documented poorer oscillator and drive behavior, and a supply that squeals under load after a cheap swap is the classic symptom. The second is the SG3525, a functionally similar controller that is not pin-compatible and keeps getting treated as one.

Verified Pin-Compatible Replacements (3 verified alternatives)

KA7500B onsemi (Fairchild line) DIP-16 / SOIC-16
100% Drop-in (Zero Code Change)
Availability & Target Pricing:

The Ubiquitous ATX Clone

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

Pin-for-pin equivalent of the TL494: same 5V reference, dual error amplifiers, dead-time comparator and dual output transistors - the part most ATX supplies were actually built with.

Same operating envelope as the TL494 (7V to 40V class supply, output stage per the datasheet).

Compatibility & Drop-In Notes: The standard repair swap in both directions. In precision designs one subtlety is worth knowing: the TL494 error-amplifier open-loop gain is slightly higher than the KA7500B, so a marginal compensation network can behave differently at the edges - check the loop if the supply misbehaves after the swap.
Package & Solder Footprint: DIP-16 / SOIC-16 pin-identical; the PCB does not know the difference.
Shenzhen Warehouse Stock & MOQ: Massive stock across fabs - and exactly why suffix verification matters (see checklist).
Request Volume Quote for KA7500B Compare TL494CDR vs KA7500B Spec Matrix
MB3759 Fujitsu / second-source fabs DIP-16
100% Drop-in (Zero Code Change)
Availability & Target Pricing:

The Japanese-Origin Equivalent

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The Fujitsu TL494-equivalent of the same architecture era - same pinout and function, found in Japanese-built supplies of the 1980s-90s.

Same envelope as the family.

Compatibility & Drop-In Notes: Same practical rule as the KA7500B swap - board-level interchange works, precision loops deserve a check after any cross-brand change.
Package & Solder Footprint: DIP-16; verify body markings on old stock.
Shenzhen Warehouse Stock & MOQ: Stocked for repair of legacy Japanese equipment.
Request Volume Quote for MB3759 Compare TL494CDR vs MB3759 Spec Matrix
SG3525 STMicroelectronics / TI / onsemi DIP-16 / SOIC-16
Functional Equivalent
Availability & Target Pricing:

Same Job, Different Wiring - Do Not Plug In

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

A voltage-mode PWM controller with a similar mission (8V to 35V supply, 500kHz class, 5.1V reference) but a different internal design: single error amplifier, built-in soft-start and shutdown, totem-pole output stage instead of the TL494 open-collector/emitter transistors.

8V to 35V operating range; 5.1V reference against the TL494 5V.

Compatibility & Drop-In Notes: Listed as the standing warning: the SG3525 is the controller people reach for when a TL494 is unavailable, and it does not fit the socket. Replacing a TL494 design with an SG3525 is a redesign task, not a repair swap.
Package & Solder Footprint: 16 pins, different assignments - inserting one into a TL494 footprint puts supply and outputs on the wrong pads.
Shenzhen Warehouse Stock & MOQ: Widely stocked in its own right; see the PWM family for its own substitution map.
Request Volume Quote for SG3525 Compare TL494CDR vs SG3525 Spec Matrix
Buyer & Quality Checklist for Sourcing Alternatives
  • Clone quality is suffix-dependent: the KA7500B family is the safe interchange, while cheaper suffix revisions (7500C and no-name equivalents) report poorer oscillator accuracy and drive strength - a supply that squeals or drifts after a cheap swap is showing you the suffix.
  • Pin 13 output-control and the dead-time pin define the topology behavior (push-pull versus single-ended, minimum gap): if a swapped-in part has "different dead-time curves" from the original, the symptom shows at light load.
  • The TL494 error amplifiers are conventionally used with the reference on the non-inverting input and the sensed rail on the inverting input - the reverse of intuition. When touching the feedback network, read the schematic against the part, not against habit.
  • One measurable cross-brand difference worth knowing: TL494 error-amp open-loop gain is specified around 70dB against about 65dB for the KA7500B. In most supplies this is invisible; in precision chargers, verify regulation after a brand swap.
  • The SG3525 lives one shelf away and is not pin-compatible. If a repair needs its features (soft-start, totem-pole drive), the board has to change with it.
  • Keep verified lots: the 16-pin PWM drawer is a classic relabeling target, and the failure mode (frequency drift) is invisible to DC tests.
Frequently Asked Technical Questions

Q: Is KA7500B the same as TL494?

A: Functionally and pin-for-pin, yes - it is the Fairchild-line clone that most ATX supplies were actually built with, and the standard repair interchange in both directions. For precision loops, note the small error-amplifier gain difference when cross-swapping brands.

Q: Can I replace a TL494 with an SG3525?

A: No. Similar job (voltage-mode PWM controller) and the same 16-pin body, but different pinout, different output stage and different support pins. It is a redesign part, not a repair substitution.

Q: Why does my power supply squeal after replacing the PWM chip?

A: Two usual causes: a cheaper clone suffix with poorer oscillator or drive behavior (the known 7500C-class issue), or a marginal compensation network reacting to the cross-brand gain difference. Fit a documented KA7500B/TL494-grade part and re-check the loop.

Technical details

Active PWM controller for multi-topology power stages

The TL494CDR is a fixed-frequency PWM controller supporting buck, boost, flyback, forward, full-bridge, half-bridge, and push-pull topologies. Its 7 V to 40 V supply range covers industrial buses without an external regulator. Two transistor-driver outputs each deliver a maximum duty cycle of 45%, which forces a push-pull or half-bridge architecture for output voltages above the input rail. The 1 kHz to 300 kHz switching frequency range lets the designer trade transformer size against core loss.

Duty-cycle ceiling and topology selection

At 45% max duty cycle per output, the TL494CDR cannot run a single-ended forward converter without a reset winding or a two-switch forward topology. The UCC2806DWTR offers a 50% duty cycle and synchronous rectifier capability, but its 47 kHz maximum switching frequency limits transformer miniaturisation.

TL494CDR
[ALLOC] verified
Quote
Parts A–Z