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Texas Instruments UCC2804DTR/81260G4
- Part No.:
- UCC2804DTR/81260G4
- Manufacturer:
- Texas Instruments
- Category:
- Power Supply Controllers, Monitors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UCC2804DTR/81260G4.pdf
- Description:
- IC OFFLINE SWITCH MULT TOP 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,100
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Product details
Overview
UCC2804DTR/81260G4 from Texas Instruments is a low-power BiCMOS current-mode PWM controller IC designed for off-line fixed-frequency switching power supplies. It features 50% maximum duty cycle, 5V reference voltage, 12.5V turn-on/8.3V turn-off UVLO thresholds, and 1A totem-pole gate driver output - enabling robust control of flyback or forward converters in AC-DC adapters and industrial power supplies.
For engineers reviewing the UCC2804DTR/81260G4 datasheet, UCC2804DTR/81260G4 pinout, UCC2804DTR/81260G4 application, or UCC2804DTR/81260G4 equivalent, key selection criteria include UVLO hysteresis (4.2V), internal leading-edge blanking (100ns), 70ns current-sense-to-output response, soft-start implementation, and SOIC-8 package compatibility with UC3842/UC3842A layouts.
Technical Context
The UCC2804DTR/81260G4 implements fixed-frequency current-mode control using an internal oscillator with RC timing (REF→RC resistor, RC→GND capacitor), a high-gain error amplifier with COMP sourcing/sinking capability, and dual current-sense comparators - one for PWM regulation and one for over-current fault protection. Its architecture includes full-cycle internal soft start and digital leading-edge blanking on the CS pin.
It operates across –40°C to +85°C, draws only 100µA startup supply current and 500µA typical operating current, supports up to 1MHz switching frequency, and delivers 1.5% tolerance on its 5V reference - making it suitable for cost-sensitive, thermally constrained off-line power designs requiring stable regulation and fast transient response.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Duty Cycle | 50% - limits peak switch conduction time to prevent transformer saturation in forward/flyback topologies. |
| Reference Voltage | 5.00 V ±1.5% - provides precise feedback reference for output voltage regulation accuracy. |
| UVLO Turn-On/Off | 12.5 V / 8.3 V - ensures reliable start-up and brownout protection in 115/230VAC-derived supplies. |
| CS Blanking Time | 100 ns - eliminates switching noise false triggering on current-sense input without external RC filter. |
| OUT Drive Current | ±1.0 A - directly drives medium-size MOSFET gates without external buffer stages. |
| Response Time | 70 ns (CS to OUT) - enables fast over-current shutdown for improved system safety and reliability. |
| Operating Temp | –40°C to +85°C - qualified for industrial-grade ambient operation without derating. |
Pinout & Package
UCC2804DTR/81260G4 is housed in an 8-pin SOIC (D package), surface-mount, RoHS-compliant, green (Pb-free, no Sb/Br) package with 1.27 mm pitch and moisture sensitivity level (MSL) 1 (260°C, unlimited).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Gate drive output | High-current totem-pole stage capable of ±1A peak; actively held low during UVLO. |
| 2 (VCC) | Power supply input | Accepts 10–12V DC; powers internal circuitry and gate driver; includes internal 13.5V zener clamp. |
| 3 (REF) | 5V reference output | Stable 5V source for error amp bias and external circuitry; requires ≥0.1µF ceramic bypass to GND. |
| 4 (GND) | Power and signal ground | Common return for all internal functions; must be low-impedance connection to minimize noise coupling. |
| 5 (FB) | Inverting error amp input | Receives feedback voltage from output divider; high-impedance node requiring short PCB trace. |
| 6 (COMP) | Error amp output / PWM comparator input | Sources/sinks current; clamped during soft start; controls duty cycle via PWM comparator threshold. |
| 7 (CS) | Current sense input | Monitors primary-side current via shunt/resistor; digitally blanked for 100ns after each OUT rising edge. |
| 8 (RC) | Oscillator timing | Connects to REF via timing resistor and to GND via timing capacitor to set switching frequency. |
Key Features
| Feature | Design Value |
|---|---|
| Internal full-cycle soft start | COMP voltage ramped over ~10 ms to limit inrush current and prevent overshoot at power-up. |
| Digital leading-edge blanking | 100 ns automatic CS disable window eliminates need for analog RC filtering and reduces propagation delay. |
| Same pinout as UC3842/UC3842A | Drop-in replacement for legacy designs - no PCB layout changes required for migration. |
| 1.5% reference tolerance | Enables tight output voltage regulation without external trimming components. |
| Low 100 µA start-up current | Reduces standby losses and allows use of high-value, cost-effective VCC start-up resistors. |
Applications
| AC-DC Adapter Power Supply | Flyback Converter for Industrial SMPS |
|---|---|
Use Scenario: 12V/2A isolated output from universal 85–264VAC input in wall-mounted adapters. IC Role / Device Role: Primary-side PWM controller regulating output via optocoupler feedback and current-mode sensing. Use Value: 50% max duty cycle prevents transformer core saturation; 12.5V/8.3V UVLO ensures reliable operation across line variations. | Use Scenario: 24V/5A regulated output in DIN-rail mounted industrial power module. IC Role / Device Role: Fixed-frequency current-mode controller managing MOSFET switching and over-current protection. Use Value: 70ns CS-to-OUT response enables fast fault shutdown; –40°C to +85°C rating supports wide ambient deployment. |
| Offline LED Driver | Isolated DC-DC Converter for PLC I/O |
Use Scenario: Constant-current 350mA LED string driver powered from 230VAC mains. IC Role / Device Role: Flyback controller with primary-side regulation, eliminating secondary-side feedback components. Use Value: Internal 5V reference and 1.5% tolerance ensure stable current setting; low 500µA operating current improves efficiency. | Use Scenario: 5V/1A isolated auxiliary supply powering digital I/O circuits in programmable logic controllers. IC Role / Device Role: Secondary-side isolated DC-DC controller providing clean, regulated bias for microcontrollers and sensors. Use Value: SOIC-8 package enables compact board layout; same pinout as UC3842 simplifies design reuse and qualification. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar current-mode PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3842N | No internal soft start or leading-edge blanking; higher 1mA start-up current; 1% reference tolerance. | Lacks integrated noise immunity features; requires external soft-start circuit and RC filter on CS. | Choose when legacy compatibility is critical and external component count is acceptable. |
| UCC2804DR81221G4 | Identical electrical specs and SOIC-8 packaging; differs only in tape-and-reel ordering code (/81221 vs /81260). | No functional difference; both are active TI part numbers with identical MSL and RoHS compliance. | Select based on distributor inventory or procurement preference - fully interchangeable in design and assembly. |
Compared with UC3842N, UCC2804DTR/81260G4 reduces BOM count via integrated soft start and blanking, while UCC2804DR81221G4 offers identical performance with alternate reel coding - making the /81260G4 optimal for new designs prioritizing noise immunity and supply chain flexibility.
Availability
UCC2804DTR/81260G4 is available at Aetrix Electronics and suitable for AC-DC adapters, industrial flyback converters, and isolated auxiliary supplies requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.
Supply support for UCC2804DTR/81260G4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor company delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The UCC280x series was designed specifically for cost-effective, high-reliability off-line current-mode switching power supplies - emphasizing low start-up current, integrated protection features, and pin compatibility with industry-standard UC384x controllers.
FAQ
What is the operating temperature range of the UCC2804DTR/81260G4?
The UCC2804DTR/81260G4 is specified for operation from –40°C to +85°C. This industrial-grade temperature range ensures reliable performance in demanding environments such as factory automation equipment, outdoor power adapters, and enclosed industrial enclosures without thermal derating. The device's BiCMOS process contributes to stable electrical characteristics across this full range.
Does the UCC2804DTR/81260G4 require an external RC filter on the CS pin?
No, the UCC2804DTR/81260G4 does not require an external RC filter on the CS pin due to its built-in 100ns digital leading-edge blanking. This feature disconnects the CS input from the comparator immediately after the OUT rising edge, effectively suppressing switch-node noise transients. External filtering may still be used in unusually noisy layouts, but it is not necessary for standard implementations of the UCC2804DTR/81260G4.
What is the purpose of the REF pin on the UCC2804DTR/81260G4?
The REF pin on the UCC2804DTR/81260G4 provides a stable 5.00 V ±1.5% reference voltage used internally by the error amplifier and other circuit blocks, and can also power external circuitry such as feedback dividers or optocoupler bias networks. It must be bypassed with at least a 0.1 µF ceramic capacitor placed close to the pin to ensure stability and low-noise operation - a requirement explicitly defined in the UCC2804DTR/81260G4 datasheet.
How does the soft start function work in the UCC2804DTR/81260G4?
The UCC2804DTR/81260G4 implements internal full-cycle soft start by clamping the COMP voltage during power-up, allowing it to rise gradually over approximately 4–10 ms depending on external compensation. This controlled ramp limits inrush current, prevents output overshoot, and ensures smooth transition into steady-state regulation. Unlike external soft-start circuits, this function requires no additional components and is active on every power cycle of the UCC2804DTR/81260G4.
Is the UCC2804DTR/81260G4 pin-compatible with the UC3842?
Yes, the UCC2804DTR/81260G4 has the same pin configuration as the UC3842 and UC3842A, including identical pin numbering, functions, and electrical behavior for OUT, VCC, GND, FB, COMP, CS, RC, and REF. This enables direct drop-in replacement in existing UC3842-based designs - retaining the same PCB layout while adding benefits like internal soft start and leading-edge blanking without modification to the UCC2804DTR/81260G4 footprint.
UCC2804DTR/81260G4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- UCC280x
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- -
- Applications:
- PWM Controller
- Voltage - Input:
- -0.3V ~ 6.3V
- Voltage - Supply:
- 8.3V ~ 11V
- Current - Supply:
- 500 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
UCC2804DTR/81260G4 FAQ
1.How can I place an order for UCC2804DTR/81260G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC2804DTR/81260G4 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for UCC2804DTR/81260G4 reliable?
The price and inventory of UCC2804DTR/81260G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC2804DTR/81260G4 is usually 5 days.
3.What payment methods are accepted for UCC2804DTR/81260G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC2804DTR/81260G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC2804DTR/81260G4?
UCC2804DTR/81260G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC2804DTR/81260G4 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for UCC2804DTR/81260G4?
For technical support, including UCC2804DTR/81260G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC2804DTR/81260G4 requirements.
6.How does Aetrix verify that UCC2804DTR/81260G4 is sourced from the original manufacturer or authorized distributors?
All UCC2804DTR/81260G4 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that UCC2804DTR/81260G4 meets industry standards.
7.What is the process for return or replacement of UCC2804DTR/81260G4?
All UCC2804DTR/81260G4 units undergo pre-shipment inspection (PSI). If there is an issue with UCC2804DTR/81260G4, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The UCC2804DTR/81260G4 part is unused and in its original packaging.
Return procedure for UCC2804DTR/81260G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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