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Texas Instruments UCC3818ADRG4
- Part No.:
- UCC3818ADRG4
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UCC3818ADRG4.pdf
- Description:
- IC PFC CTR AVERAGE 220KHZ 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,773
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Product details
Overview
UCC3818ADRG4 from Texas Instruments is a BiCMOS average current-mode power factor correction (PFC) controller for boost preregulators, operating from 12 V to 18 V supply, featuring 7.5 V reference output, 10.2 V/9.7 V UVLO turn-on/turn-off thresholds, and ±1.2 A peak gate drive capability. It enables near-unity power factor in sub-300 W IEC61000-3-2-compliant AC-DC supplies.
For engineers reviewing the UCC3818ADRG4 datasheet, UCC3818ADRG4 pinout, UCC3818ADRG4 application, or UCC3818ADRG4 equivalent, key selection considerations include its average current mode control architecture, feed-forward line regulation, leading-edge PWM modulation, OVP/EN dual-function pin, and compatibility with fixed-VCC supply topologies.
Technical Context
The UCC3818ADRG4 implements average current mode control using a high-gain (90 dB) current amplifier and a precision analog multiplier with three inputs (VAOUT, IAC, VFF) to generate a duty-cycle command proportional to instantaneous line voltage and output error. Its oscillator supports 6 kHz–220 kHz operation via RT/CT programming, with ramp amplitude of 4.0 VPP and peak at 5.0 V.
It integrates a 7.5 V ±1.5% voltage reference (20 mA sink/source), low-offset (±2 mV) current amplifier, zero-power comparator (0.33 V threshold), and overvoltage protection with 500 mV hysteresis referenced to VREF. The OVP/EN pin functions as both enable input (1.9 V threshold) and output overvoltage latch.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 12 V to 18 V - supports fixed-supply biasing without bootstrap circuitry |
| UVLO Threshold | 10.2 V turn-on / 9.7 V turn-off - ensures stable startup and brownout recovery in fixed-VCC systems |
| Reference Voltage | 7.5 V ±1.5% - powers external circuitry and serves as precision scaling reference for sensing |
| Gate Drive Strength | ±1.2 A peak - drives MOSFET gates directly with low Rpullup (9 Ω) and Rpulldown (4 Ω) |
| Oscillator Frequency | 6 kHz to 220 kHz - programmable via RT resistor and CT capacitor for EMI optimization |
| Current Amplifier Offset | ±2 mV - minimizes light-load current distortion and improves THD performance |
| Multiplication Gain K | 1/V - enables accurate feed-forward line regulation and stable average-current loop |
Pinout & Package
UCC3818ADRG4 is housed in a 16-pin SOIC (D) package measuring 4.90 mm × 3.91 mm, with standard JEDEC MS-012AC footprint and gull-wing leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 GND | Power and signal reference ground | Common return for all analog and power paths; requires low-inductance 0.1 µF ceramic bypass |
| 2 PKLMT | Peak current limit sense input | Accepts negative-going voltage from current-sense resistor; triggers shutdown when < 0 V |
| 3 CAOUT | Current amplifier output | Drives PWM latch; connects to compensation network between CAOUT and MOUT |
| 4 CAI | Current amplifier noninverting input | Connects to low-side current-sense resistor; operates down to –0.5 V for bidirectional sensing |
| 5 MOUT | Multiplier output / current amp inverting input | High-impedance node combining multiplier current and CA feedback; enables differential sensing |
| 6 IAC | Line voltage proportional current input | Accepts up to 500 µA RMS-representative current; sets multiplier gain scale |
| 7 VAOUT | Voltage error amplifier output | Regulates bulk capacitor voltage; clamped to ~5.5 V to prevent overshoot |
| 8 VFF | Feed-forward voltage input | Receives filtered RMS line voltage (1.4 V at low line); improves line regulation and reduces THD |
| 9 VREF | 7.5 V precision reference output | Stable 20 mA-capable reference for external biasing and sensing scaling |
| 10 OVP/EN | Overvoltage protection / enable input | Disables DRVOUT if bulk voltage exceeds 1.07×VREF + 500 mV hysteresis; also enables at >1.9 V |
| 11 SSENSE | Voltage amplifier inverting input | Connects to output voltage divider; forms feedback loop with VAOUT for output regulation |
| 12 RT | Oscillator timing current input | Sets charging current for CT capacitor; nominal 3 V bias; 10 kΩ–100 kΩ recommended |
| 13 SS | Soft-start control input | Charges external capacitor with –10 µA current source; ramps duty cycle linearly at startup |
| 14 CT | Oscillator timing capacitor connection | Grounded capacitor sets switching frequency; short direct trace required for noise immunity |
| 15 VCC | Positive supply input | 12–18 V operation; must be bypassed locally with ≥0.1 µF ceramic capacitor |
| 16 DRVOUT | Gate driver output | Totem-pole MOSFET driver; ±1.2 A peak; requires series gate resistor to damp ringing |
Key Features
| Feature | Design Value |
|---|---|
| Average current mode control | Enables stable, low-distortion sinusoidal line current with inherent noise immunity and wide bandwidth |
| Leading-edge PWM modulation | Reduces ripple current in bulk capacitor when synchronized with downstream DC-DC stage |
| Feed-forward line regulation | VFF input compensates for line voltage variations, improving dynamic response and reducing THD |
| Integrated 7.5 V reference | ±1.5% accuracy, 20 mA drive capability - eliminates need for external reference in most PFC designs |
| Zero-power detection | 0.33 V threshold on VAOUT - latches DRVOUT low during no-load or standby to minimize idle losses |
| Overvoltage protection with hysteresis | 500 mV hysteresis on OVP/EN pin prevents oscillation during transient overvoltage events |
Applications
| PC Power Supply | LED Driver Input Stage |
|---|---|
|
Use Scenario: 250 W ATX-compatible front-end with universal AC input (85–265 VAC) and IEC61000-3-2 Class C compliance. IC Role / Device Role / Timing Role: Primary PFC controller regulating boost converter to shape input current waveform and maintain >0.95 power factor. Use Value: Enables compact design with <300 W output while meeting harmonic limits; leverages 10.2 V UVLO for reliable startup across global mains. |
Use Scenario: Constant-power LED driver for commercial lighting with 100–277 VAC input and 48 V/3 A output. IC Role / Device Role / Timing Role: Active PFC preregulator ensuring stable DC bus for downstream flyback or LLC stage. Use Value: Reduces input current THD to <10% at full load; feed-forward (VFF) maintains regulation across wide input range. |
| Industrial AC-DC Adapter | Consumer Audio Power Supply |
|
Use Scenario: 150 W industrial adapter powering PLC I/O modules, requiring robust operation from –40°C to 85°C. IC Role / Device Role / Timing Role: Fixed-VCC PFC controller managing boost stage under variable load and line conditions. Use Value: Low 150 µA start-up current and ±2 mV current amp offset ensure stable light-load operation and low standby loss. |
Use Scenario: High-fidelity audio amplifier power supply with ultra-low noise requirements and 120 W output. IC Role / Device Role / Timing Role: PFC controller minimizing conducted EMI through leading-edge modulation and precise current sensing. Use Value: 90 dB open-loop gain and differential current sensing (CAI/MOUT) suppress common-mode noise coupling into analog stages. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PFC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC3817ADRG4 | 16 V/10 V UVLO, integrated shunt regulator, designed for bootstrap supply topologies | Preferred where VCC is derived from auxiliary winding; not suitable for fixed-VCC designs | Select UCC3817ADRG4 only when bootstrap biasing is used; UCC3818ADRG4 is mandatory for fixed 12–18 V supply |
| UC3854BDW | Higher power rating (2 kW+), ACM control, no integrated VREF, requires external reference and bias | Targeted at >500 W industrial PFC; lacks soft-start, OVP/EN integration, and feed-forward support | Choose UC3854BDW for high-power continuous conduction mode (CCM); UCC3818ADRG4 better suited for cost-sensitive <300 W CRM designs |
Compared with UCC3817ADRG4, UCC3818ADRG4 offers lower UVLO for fixed-supply use and omits the shunt regulator; versus UC3854BDW, it delivers higher integration, lower system BOM count, and optimized performance below 300 W with built-in protections and feed-forward.
Availability
UCC3818ADRG4 is available at Aetrix Electronics and suitable for PC power supplies, LED driver input stages, industrial AC-DC adapters, and consumer audio power supplies requiring stable component supply and long-term production continuity.
Supply support for UCC3818ADRG4 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The UCC3818A product line was engineered specifically for cost-effective, high-efficiency active power factor correction in sub-300 W AC-DC power supplies, emphasizing average current mode control, fixed-VCC operation, and IEC61000-3-2 compliance.
FAQ
What is the UVLO behavior of the UCC3818ADRG4?
The UCC3818ADRG4 features an undervoltage lockout with 10.2 V turn-on and 9.7 V turn-off thresholds, providing 0.5 V hysteresis. This ensures clean startup and reliable brownout recovery in fixed-VCC applications. Below 9.7 V, the device disables DRVOUT and resets internal logic; VREF remains inactive until VCC exceeds 10.2 V. This behavior is confirmed in Section 8.5 of the SLUS577D datasheet.
Does the UCC3818ADRG4 support critical conduction mode (CRM)?
Yes, the UCC3818ADRG4 supports average current mode control in both continuous and critical conduction modes. Its architecture-including the current amplifier, multiplier, and PWM latch-is optimized for CRM operation in boost preregulators up to 300 W. The device's low current-sense offset (±2 mV) and fast propagation delay (<500 ns) ensure stable boundary-mode control with minimal distortion, as validated in TI Application Report SLUA454.
How does the OVP/EN pin function in the UCC3818ADRG4?
The OVP/EN pin on the UCC3818ADRG4 serves dual roles: as an overvoltage protection input (threshold = 1.07×VREF + 500 mV hysteresis) and as an enable input (threshold = 1.9 V). When voltage exceeds the OVP threshold, DRVOUT is immediately disabled and latched off until reset. When pulled below 1.9 V, the device disables DRVOUT and discharges the SS capacitor to force soft restart. Both functions are internally implemented and require no external components.
What is the purpose of the VFF pin on the UCC3818ADRG4?
The VFF (feed-forward voltage) pin on the UCC3818ADRG4 accepts a filtered RMS representation of the AC line voltage-typically 1.4 V at low line and ~4.7 V at high line-to scale the multiplier output. This enables automatic adjustment of current reference with line voltage, improving line regulation and reducing total harmonic distortion (THD) across universal input ranges. The VFF path is internally trimmed for ±1% matching to the IAC current input.
Can the UCC3818ADRG4 operate without an external soft-start capacitor?
No-the UCC3818ADRG4 requires an external capacitor on the SS pin to implement controlled soft-start. The internal –10 µA current source charges this capacitor to ramp the effective error voltage, limiting initial duty cycle and preventing inrush current. Leaving SS unconnected or shorted to ground results in undefined or unstable startup behavior. Typical values range from 100 nF to 1 µF, selected based on desired startup time per Equation 5 in the SLUS577D datasheet.
UCC3818ADRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Mode:
- Average Current
- Frequency - Switching:
- 6kHz ~ 220kHz
- Current - Startup:
- 150 µA
- Voltage - Supply:
- 12V ~ 17V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
UCC3818ADRG4 FAQ
1.How can I place an order for UCC3818ADRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC3818ADRG4 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 UCC3818ADRG4 reliable?
The price and inventory of UCC3818ADRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC3818ADRG4 is usually 5 days.
3.What payment methods are accepted for UCC3818ADRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC3818ADRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC3818ADRG4?
UCC3818ADRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC3818ADRG4 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 UCC3818ADRG4?
For technical support, including UCC3818ADRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC3818ADRG4 requirements.
6.How does Aetrix verify that UCC3818ADRG4 is sourced from the original manufacturer or authorized distributors?
All UCC3818ADRG4 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 UCC3818ADRG4 meets industry standards.
7.What is the process for return or replacement of UCC3818ADRG4?
All UCC3818ADRG4 units undergo pre-shipment inspection (PSI). If there is an issue with UCC3818ADRG4, 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 UCC3818ADRG4 part is unused and in its original packaging.
Return procedure for UCC3818ADRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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