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Texas Instruments UCC28730DR
- Part No.:
- UCC28730DR
- Manufacturer:
- Texas Instruments
- Category:
- AC DC Converters, Offline Switches
- Package:
- 8-SOIC (0.154", 3.90mm Width), 7 Leads
- Datasheet:
-
UCC28730DR.pdf
- Description:
- IC OFFLINE SWITCH FLYBACK 7SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,211
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Product details
Overview
UCC28730DR from Texas Instruments is a primary-side regulation (PSR) flyback controller for isolated AC/DC power supplies, enabling ±5% CV/CC output regulation without optocoupler feedback. It integrates a 700-V startup switch, valley-switching control, and wake-up monitoring for <5 mW no-load input power at 115/230 VRMS. Used in USB chargers and auxiliary supplies requiring ultra-low standby consumption.
For engineers reviewing the UCC28730DR datasheet, UCC28730DR pinout, UCC28730DR application, or UCC28730DR equivalent, key selection criteria include its 83-kHz max switching frequency, 32-Hz min frequency for zero-power standby, ±5% regulation accuracy across line/load, integrated HV startup, and compatibility with secondary-side wake-up ICs like UCC24650.
Technical Context
The UCC28730DR operates in discontinuous conduction mode (DCM) with resonant-ring valley-switching to minimize switching losses and improve efficiency. Its dual modulation scheme combines frequency modulation (fSW = 32 Hz–83 kHz) and amplitude modulation (peak primary current control) to maintain high conversion efficiency across full load and line ranges.
Control logic uses sampled auxiliary winding voltage at demagnetization end for precise output voltage sensing and timing. Wake-up detection on the VS pin responds to either high-threshold (2 V) or low-threshold (57 mV) signals from secondary-side devices, enabling rapid load-step recovery with minimal output capacitance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Switching Frequency | 83.3 kHz - Enables compact magnetics and EMI-compliant designs in low-standby-power chargers |
| Min Switching Frequency | 32 Hz - Supports <5 mW no-load input power by drastically reducing switching activity at light loads |
| Voltage Regulation Accuracy | ±5% - Maintains stable output under varying AC line (115/230 VRMS) and load conditions without optocoupler |
| Startup Voltage Source | Integrated 700-V HV pin - Directly charges VDD capacitor from rectified bulk voltage; eliminates external high-voltage start-up circuit |
| Wake-Up Thresholds | 2 V (high) / 57 mV (low) on VS pin - Allows interoperability with diverse secondary-side drivers (e.g., UCC24650) for fast transient response |
| Current Sense Threshold Range | 249 mV (min) to 740 mV (max) - Enables precise constant-current regulation across wide output current range |
| Supply Current (Wait State) | 75 µA - Minimizes bias power loss during ultra-low-power standby operation |
Pinout & Package
UCC28730DR is housed in a 7-pin SOIC package (4.90 mm × 3.90 mm), optimized for compact offline flyback designs with creepage/clearance compliance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1. VDD | Bias supply input | Accepts 9–35 V; UVLO turn-on at 21 V, turn-off at 7.7 V; requires local 0.047-µF bypass capacitor |
| 2. VS | Voltage sense & wake-up input | Connects to auxiliary winding divider; provides output voltage sampling, demagnetization timing, line sensing, and wake-up signal detection |
| 3. CBC | Cable compensation programming | Resistor-to-GND sets output voltage boost (0–400 mV) to compensate for cable IR drop in USB charging applications |
| 4. GND | Signal and power ground reference | Single ground for analog sensing and gate-drive return; critical for noise immunity on VS/CS pins |
| 5. CS | Primary current sense input | Monitors MOSFET source current via RCS; includes 225-ns leading-edge blanking and line-compensation capability |
| 6. DRV | Gate drive output | Clamped 14.5-V source/sink driver; 29-mA turn-on current limits dv/dt; internal 200-kΩ pull-down in start state |
| 7. HV | High-voltage startup input | Connects directly to bulk capacitor; delivers ~250 µA startup current; leakage <0.5 µA in run state |
Key Features
| Feature | Design Value |
|---|---|
| Zero-power standby | Supports <5 mW no-load input power at 115/230 VRMS via adaptive frequency reduction down to 32 Hz |
| Primary-side regulation (PSR) | Eliminates optocoupler and TL431, reducing BOM cost and improving reliability in isolated flyback topologies |
| Valley-switching operation | Reduces MOSFET switching losses by turning on at drain voltage minima, increasing overall efficiency |
| Smart wake-up monitoring | Detects secondary-side wake-up signals (2 V or 57 mV) to trigger immediate load-step response without large output capacitors |
| Programmable cable compensation | Adjusts regulated output voltage up to 400 mV based on load current to maintain target voltage at device connector |
Applications
| USB Wall Chargers | TV Auxiliary Supplies |
|---|---|
Use Scenario: 5-V/2-A USB charging adapter for smartphones and tablets operating from universal AC input. IC Role / Device Role / Timing Role: PSR flyback controller managing CV/CC regulation, valley-switching timing, and wake-up event detection from UCC24650. Use Value: Achieves Energy Star Tier 2 and DOE Level VI compliance with <30 mW no-load power and ±5% output accuracy. | Use Scenario: Standby power supply for smart TV mainboard, delivering 3.3 V/0.5 A during system sleep mode. IC Role / Device Role / Timing Role: Primary-side controller maintaining regulation during deep-sleep states while responding to remote-control wake pulses. Use Value: Enables <5 mW standby consumption without auxiliary winding bias winding or optocoupler, simplifying transformer design. |
| Home Appliance SMPS | Industrial Control Auxiliary Power |
Use Scenario: Isolated 12-V/0.3 A power supply for washing machine control board with wide input voltage range. IC Role / Device Role / Timing Role: Flyback controller providing line-compensated current limiting and overvoltage protection using only primary-side sensing. Use Value: Eliminates secondary feedback components, reducing failure points and meeting IEC 60335 safety requirements. | Use Scenario: 24-V/0.2 A auxiliary supply for PLC I/O modules requiring robust EMI performance and thermal stability. IC Role / Device Role / Timing Role: Controller operating in DCM with frequency dithering and thermal shutdown (165°C) for industrial ambient conditions. Use Value: Delivers >85% efficiency across –40°C to +125°C junction temperature with built-in OVP, OCP, and thermal protection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PSR flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28710DR | Lacks wake-up monitoring; 70-kHz max fSW; no cable compensation; lower standby current (50 µA wait-state) | Suitable for cost-sensitive, non-USB applications where fast load-step response is not required | Select UCC28710DR when wake-up signaling and programmable cable compensation are unnecessary |
| LNK364PG | Integrated MOSFET (725 V); fixed 66-kHz fSW; no valley switching; higher no-load power (~15 mW) | Targeted at simpler, lower-cost adapters without tight standby or dynamic response requirements | Choose LNK364PG for ultra-minimal BOM count where integrated switch suffices and <5 mW standby is not mandatory |
Compared with UCC28710DR and LNK364PG, the UCC28730DR uniquely combines wake-up monitoring, cable compensation, and valley-switching to deliver <5 mW standby power with rapid transient response-making it optimal for USB-C and smart-device charging applications demanding both efficiency and responsiveness.
Availability
UCC28730DR is available at Aetrix Electronics and suitable for USB wall chargers, TV auxiliary supplies, home appliance SMPS, and industrial control auxiliary power requiring stable component supply and long-term lifecycle support.
Supply support for UCC28730DR 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 specializing in analog and embedded processing technologies, with leadership in power management ICs for energy-efficient systems.
The UCC28730DR belongs to TI's Zero-Power Standby PSR Flyback Controller product line, designed specifically for ultra-low-no-load AC/DC converters in consumer and industrial charging applications.
FAQ
What is the minimum switching frequency of the UCC28730DR and how does it enable zero-power standby?
The UCC28730DR supports a minimum switching frequency of 32 Hz, dynamically reducing switching activity under light/no-load conditions. This ultra-low frequency operation minimizes gate-drive and switching losses, allowing the UCC28730DR to achieve <5 mW no-load input power at both 115 VRMS and 230 VRMS inputs-meeting stringent global energy-efficiency standards such as DOE Level VI and Energy Star.
How does the UCC28730DR implement primary-side regulation without an optocoupler?
The UCC28730DR samples the reflected auxiliary winding voltage at the end of transformer demagnetization to infer output voltage, eliminating the need for optocoupler-based feedback. Combined with precise current sensing on the primary side and internal regulation algorithms, the UCC28730DR achieves ±5% voltage and current regulation accuracy across line and load variations-reducing component count and improving system reliability.
What is the function of the CBC pin on the UCC28730DR and how is it configured?
The CBC (Cable Compensation) pin on the UCC28730DR accepts a resistor-to-GND to program output voltage boost proportional to load current, compensating for voltage drop across USB cables. With CBC shorted, maximum compensation is ~400 mV for a 5-V output; typical RCBC values range from 10 kΩ to open circuit. The UCC28730DR generates 0–3.13 V on CBC, which is summed into the VS feedback network to raise regulation setpoint linearly with IOUT.
Which secondary-side IC is recommended to interface with the UCC28730DR for wake-up functionality?
The UCC24650 is the designated secondary-side wake-up monitor IC for use with the UCC28730DR. It detects load steps on the output and injects a wake-up pulse onto the auxiliary winding, which the UCC28730DR senses on its VS pin. The UCC28730DR supports two wake-up thresholds (2 V high-level and 57 mV low-level), enabling interoperability with both low-impedance and high-impedance secondary drivers like the UCC24650.
Does the UCC28730DR include built-in protection features, and what are they?
Yes, the UCC28730DR integrates multiple protection functions: overvoltage protection (OVP) triggered at 4.62 V on the VS pin, overcurrent protection (OCP) at 1.5 V on the CS pin, line undervoltage lockout (UVLO) with run/stop thresholds set by VS current (225 µA/80 µA), and thermal shutdown at 165°C. These protections operate autonomously using primary-side sensing-no external components required-ensuring robust operation across fault conditions.
UCC28730DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width), 7 Leads
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Isolation:
- Isolated
- Internal Switch(s):
- No
- Voltage - Breakdown:
- -
- Topology:
- Flyback
- Voltage - Start Up:
- 21 V
- Voltage - Supply (Vcc/Vdd):
- 9V ~ 35V
- Duty Cycle:
- -
- Frequency - Switching:
- 32Hz ~ 83kHz
- Power (Watts):
- -
- Fault Protection:
- Current Limiting, Over Voltage
- Control Features:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 7-SOIC
- Mounting Type:
- Surface Mount
UCC28730DR FAQ
1.How can I place an order for UCC28730DR through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC28730DR 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 UCC28730DR reliable?
The price and inventory of UCC28730DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC28730DR is usually 5 days.
3.What payment methods are accepted for UCC28730DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC28730DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC28730DR?
UCC28730DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC28730DR 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 UCC28730DR?
For technical support, including UCC28730DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC28730DR requirements.
6.How does Aetrix verify that UCC28730DR is sourced from the original manufacturer or authorized distributors?
All UCC28730DR 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 UCC28730DR meets industry standards.
7.What is the process for return or replacement of UCC28730DR?
All UCC28730DR units undergo pre-shipment inspection (PSI). If there is an issue with UCC28730DR, 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 UCC28730DR part is unused and in its original packaging.
Return procedure for UCC28730DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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