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Texas Instruments UCC2804PWTR
- Part No.:
- UCC2804PWTR
- Manufacturer:
- Texas Instruments
- Category:
- Power Supply Controllers, Monitors
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
UCC2804PWTR.pdf
- Description:
- IC OFFLINE SW MULT TOP 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,750
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Product details
Overview
UCC2804PWTR from Texas Instruments is a low-power, current-mode PWM controller IC designed for fixed-frequency off-line and DC-to-DC switching power supplies. It features 50% maximum duty cycle, 12.5 V turn-on/8.3 V turn-off UVLO thresholds, 5 V reference (±1.5% tolerance), 1 A totem-pole gate driver output, and internal leading-edge blanking - enabling robust operation in automotive PSU and industrial AC/DC adapters.
For engineers reviewing the UCC2804PWTR datasheet, UCC2804PWTR pinout, UCC2804PWTR application, or UCC2804PWTR equivalent, this device serves as a drop-in functional upgrade over UC3842A with lower quiescent current (500 μA typ), faster CS-to-OUT response (70 ns), and integrated full-cycle soft start - critical for high-reliability, space-constrained SMPS designs requiring stable startup and fault recovery.
Technical Context
The UCC2804PWTR implements a BiCMOS current-mode control architecture with dual comparators on the CS pin (PWM + overcurrent), digital leading-edge blanking (50–150 ns), and a true low-impedance 2-MHz error amplifier. Its oscillator uses REF-derived charging current into an external RC network to achieve up to 1 MHz operation, with frequency set by Equation f = 1.5/(R × C).
Unlike UC3842A, it integrates full-cycle soft start (COMP rise time: 4–10 ms), internal fault soft start, and a 1.5% accurate 5 V reference. The 50% max duty cycle is hardwired via internal logic, making it suitable for forward or half-bridge topologies where duty cycle limitation prevents transformer saturation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Duty Cycle | 50% - hardwired limit prevents transformer core saturation in forward converters and enables safe half-bridge operation. |
| UVLO Thresholds | 12.5 V turn-on / 8.3 V turn-off - provides 4.2 V hysteresis for reliable startup and brownout immunity in 12 V nominal input systems. |
| Reference Voltage | 5.0 V ±1.5% - high-accuracy internal reference reduces need for external trimming in feedback loop design. |
| Gate Drive Output | ±1 A peak - directly drives medium-size MOSFET gates without external buffers, reducing BOM count and layout complexity. |
| CS-to-OUT Delay | 70 ns typical - enables high-frequency (>500 kHz) current-mode control with minimal phase lag and improved transient response. |
| Start-up Current | 100 μA typical - allows use of high-value, cost-effective startup resistors and extends hold-up time in AC/DC applications. |
| Oscillator Frequency | Up to 1 MHz - supports compact magnetics and high-density power supply designs while maintaining stable current-mode operation. |
Pinout & Package
TSSOP-8 (PW) package: 4.40 mm × 3.00 mm body, 0.65 mm pitch, surface-mount, moisture-sensitive level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - COMP | Error amplifier output / PWM comparator input | True low-Z op-amp output (sources/sinks current); clamped during soft start; zero-duty command possible by pulling to GND. |
| 2 - FB | Inverting input of error amplifier | High-bandwidth (2 MHz) node; requires short trace and minimal stray capacitance for loop stability in voltage-mode derived designs. |
| 3 - CS | Current sense input (dual comparator) | Connects to MOSFET source resistor; internal 100 ns leading-edge blanking eliminates need for external RC filter in most layouts. |
| 4 - RC | Oscillator timing input | Accepts current from REF to charge external capacitor; sets frequency via f = 1.5/(R × C); sensitive to ground routing. |
| 5 - GND | Power and signal reference ground | Common return for all analog/digital functions; must be low-impedance and separated from power ground in high-noise SMPS. |
| 6 - OUT | Gate driver output | ±1 A capable totem-pole stage; actively held low during UVLO; no external clamp diodes needed due to rail-to-rail swing. |
| 7 - VCC | Supply input with UVLO | Powered via current-limiting resistor; internal Zener clamps at ~13.5 V; bypass with ≥1 µF ceramic + 0.1 µF close to pin. |
| 8 - REF | 5 V reference output | Stable 5 V supply for external circuitry; requires 0.1 µF ceramic bypass; sinks up to 5 mA; indicates power status when pulled low below UVLO. |
Key Features
| Feature | Design Value |
|---|---|
| Internal full-cycle soft start | Fixed 4–10 ms COMP ramp eliminates external soft-start components (R/C/PNP), reducing BOM and PCB area. |
| Digital leading-edge blanking | 50–150 ns blanking window removes switch-node noise from CS path, enabling direct connection to source resistor without RC filter. |
| True low-Z error amplifier | 2 MHz gain-bandwidth, bidirectional current capability (source/sink), improves loop response vs UC3842's open-collector output. |
| Pinout compatibility with UC3842A | Same 8-pin SOIC/TSSOP mapping enables drop-in replacement in legacy designs with improved performance and lower IQ. |
| Low operating supply current | 500 μA typical (vs ~10 mA for UC3842) - extends startup time, reduces dissipation, and improves light-load efficiency. |
Applications
| Automotive Power Supply | Industrial AC/DC Adapter |
|---|---|
|
Use Scenario: 12 V battery-fed DC/DC converter powering infotainment or ADAS ECUs in vehicles with wide input transients (-0.5 V to 28 V). IC Role / Device Role / Timing Role: Primary-side current-mode PWM controller regulating isolated flyback output; handles cold-crank (4.5 V) and load-dump (28 V) events via robust UVLO hysteresis. Use Value: 4.2 V UVLO hysteresis and 50% duty cycle prevent transformer saturation during sustained overvoltage, improving system reliability under ISO 16750-2 stress conditions. |
Use Scenario: Compact 24 W offline flyback adapter for factory automation sensors, operating from 85–265 VAC with high efficiency and low standby power. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller managing primary-side regulation, gate drive, and fault protection without optocoupler feedback. Use Value: 100 μA start-up current enables high-value startup resistor (≥1 MΩ), reducing no-load losses; integrated soft start ensures clean output ramp during plug-in events. |
| Half-Bridge DC/DC Converter | High-Density Telecom Module |
|
Use Scenario: 48 V input, 12 V output half-bridge converter in telecom shelf power, requiring precise duty cycle control and fast transient response. IC Role / Device Role / Timing Role: Master PWM controller generating complementary gate signals (with external logic) and monitoring primary current for cycle-by-cycle limiting. Use Value: Hardwired 50% max duty cycle guarantees dead-time margin and prevents shoot-through risk in bridge configurations without external duty cycle clamping. |
Use Scenario: 3 kW modular power supply unit using interleaved forward converters, where multiple UCC2804PWTR controllers coordinate phase-shifted operation. IC Role / Device Role / Timing Role: Synchronized current-mode controller per phase, leveraging 1 MHz capability and low propagation delay (70 ns) for tight current sharing. Use Value: 70 ns CS-to-OUT delay minimizes current-sense latency across phases, enabling <5% inter-phase current imbalance at full load and 200 kHz switching. |
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 |
|---|---|---|---|
| UC3842A | Higher 10 mA operating current; 500 kHz max frequency; open-collector COMP; no internal soft start or leading-edge blanking. | Lacks integrated fault recovery and noise immunity; requires external soft-start and RC filter on CS; limited to ≤500 kHz designs. | Select UC3842A only for cost-sensitive, legacy-replacement scenarios where 500 kHz and higher IQ are acceptable. |
| UCC2802D | Same family, SOIC-8 package; identical electrical specs but different thermal resistance (RθJA = 117.9°C/W vs PW's 150°C/W); same 100% duty cycle variant. | SOIC-8 offers easier hand-soldering and higher thermal mass; less suitable for ultra-dense layouts than TSSOP-8. | Choose UCC2802D for prototyping or low-volume production where thermal margin > PCB density is prioritized. |
Compared with UC3842A, UCC2804PWTR delivers 95% lower operating current and 2× higher frequency capability, while UCC2802D shares identical functionality but trades TSSOP density for SOIC manufacturability - making UCC2804PWTR optimal for high-efficiency, space-constrained automotive and telecom modules.
Availability
UCC2804PWTR is available at Aetrix Electronics and suitable for automotive power supplies, industrial AC/DC adapters, and high-density telecom modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for UCC2804PWTR 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 leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in power conversion and automotive-grade reliability.
The UCC280x product line was engineered specifically for high-efficiency, low-component-count current-mode SMPS in automotive, industrial, and telecom applications - emphasizing low IQ, integrated protection, and pin compatibility with legacy UC384x controllers.
FAQ
What is the maximum operating frequency of the UCC2804PWTR?
The UCC2804PWTR supports oscillator frequencies up to 1 MHz, enabled by its BiCMOS process and high-speed internal comparators. This allows compact magnetic design and high switching efficiency in space-constrained applications. The actual frequency is set externally via resistor (REF to RC) and capacitor (RC to GND), using f = 1.5/(R × C). At 1 MHz, the UCC2804PWTR maintains stable current-mode control and 70 ns CS-to-OUT response.
Does the UCC2804PWTR require an external soft-start circuit?
No, the UCC2804PWTR integrates full-cycle soft start with a fixed COMP voltage ramp (4–10 ms to 5 V), eliminating the need for external resistors, capacitors, or transistors. This internal soft start activates at power-up and during fault recovery, ensuring controlled output voltage ramp and preventing inrush current. The feature is confirmed in the device's functional block diagram and Section 7.3.1.1 of the datasheet.
How does the UCC2804PWTR differ from the UC3842A in current sensing?
The UCC2804PWTR features dual current-sense comparators (PWM + overcurrent) and digital leading-edge blanking (50–150 ns), whereas UC3842A has only one comparator and no blanking. This allows UCC2804PWTR to connect CS directly to the MOSFET source resistor without an external RC filter, reducing component count and propagation delay (70 ns vs >200 ns). Its CS gain is also lower (1.65 V/V vs 3 V/V), optimizing noise immunity.
What is the purpose of the REF pin on the UCC2804PWTR?
The REF pin on the UCC2804PWTR delivers a precision 5 V ±1.5% reference used for the error amplifier, oscillator timing, and internal logic. It can source up to 5 mA and must be bypassed with ≥0.1 µF ceramic capacitor. When VCC is below UVLO, REF is pulled low through a 5 kΩ resistor - enabling its use as a power-good indicator. This dual-role functionality simplifies auxiliary biasing and status monitoring in SMPS designs.
Is the UCC2804PWTR pin-compatible with UC3842A?
Yes, the UCC2804PWTR has identical pin configuration and numbering to UC3842A in both SOIC-8 and TSSOP-8 packages, enabling direct PCB footprint reuse. However, it is not a plug-in replacement: internal differences (e.g., full-cycle soft start, leading-edge blanking, lower IQ) may require minor schematic updates like removing external soft-start components or RC filters. Functional equivalence is confirmed in TI's device comparison table and Section 7.3 of the datasheet.
UCC2804PWTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- UCC280x
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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-TSSOP
UCC2804PWTR FAQ
1.How can I place an order for UCC2804PWTR through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC2804PWTR 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 UCC2804PWTR reliable?
The price and inventory of UCC2804PWTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC2804PWTR is usually 5 days.
3.What payment methods are accepted for UCC2804PWTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC2804PWTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC2804PWTR?
UCC2804PWTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC2804PWTR 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 UCC2804PWTR?
For technical support, including UCC2804PWTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC2804PWTR requirements.
6.How does Aetrix verify that UCC2804PWTR is sourced from the original manufacturer or authorized distributors?
All UCC2804PWTR 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 UCC2804PWTR meets industry standards.
7.What is the process for return or replacement of UCC2804PWTR?
All UCC2804PWTR units undergo pre-shipment inspection (PSI). If there is an issue with UCC2804PWTR, 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 UCC2804PWTR part is unused and in its original packaging.
Return procedure for UCC2804PWTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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