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Texas Instruments UC2842ADWTRG4
- Part No.:
- UC2842ADWTRG4
- Manufacturer:
- Texas Instruments
- Category:
- Power Supply Controllers, Monitors
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
UC2842ADWTRG4.pdf
- Description:
- IC PWM BOOST FLYBACK CM 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,196
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Product details
Overview
UC2842ADWTRG4 from Texas Instruments is a current-mode PWM controller IC designed for off-line and DC-DC switch-mode power supplies. It features 8.3 mA trimmed oscillator discharge current, <0.5 mA start-up current, undervoltage lockout with hysteresis (16 V ON / 10 V OFF), up to 500 kHz operation, and a 1 A totem-pole output stage driving MOSFET gates directly in flyback and forward converters.
For engineers reviewing the UC2842ADWTRG4 datasheet, UC2842ADWTRG4 pinout, UC2842ADWTRG4 application, or UC2842ADWTRG4 equivalent, key selection criteria include its 8-pin SOIC (DW) package, peak-current-mode control architecture, pulse-by-pulse current limiting, internal 5 V reference, and compatibility with universal-input AC/DC adapters and industrial DC-DC modules.
Technical Context
The UC2842ADWTRG4 implements fixed-frequency peak-current-mode control using an internal oscillator programmed via RT/CT, a high-gain error amplifier (80 dB open-loop gain), and a current-sense comparator clamping at 1 V. Its UVLO threshold (16 V turn-on, 10 V turn-off) supports stable startup in off-line applications with bulk capacitor biasing.
During normal operation, the IC regulates duty cycle by comparing the error amplifier output against the sensed primary-side current ramp. Pulse-by-pulse limiting ensures cycle-by-cycle protection, while automatic feedforward compensation improves line transient response without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Discharge Current | 8.3 mA (trimmed; enables precise max duty cycle programming independent of process variation) |
| Start-up Current | < 0.5 mA (reduces power loss in high-voltage start-up resistor for AC/DC front-end) |
| UVLO Threshold | 16 V ON / 10 V OFF (provides 6 V hysteresis for reliable power-up/down sequencing in off-line PSUs) |
| Output Drive | 1 A sink/source (directly drives medium-power MOSFET gates without external buffer) |
| Reference Voltage | 5.0 V ±50 mV (internally trimmed; powers feedback circuitry and serves as precision voltage reference) |
| Max Switching Frequency | 500 kHz (supports compact magnetics and high-density power supply designs) |
| Error Amp Gain | 80 dB (enables stable loop compensation for isolated flyback and forward topologies) |
Pinout & Package
UC2842ADWTRG4 is housed in a 16-pin SOIC (DW) package measuring 10.30 mm × 10.30 mm, optimized for thermal performance and board-level reliability in industrial power supplies.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC | Bias supply input | Accepts 11–30 V; powers internal circuitry and gate driver; requires ≥10× VREF bypass capacitance |
| VREF | 5 V reference output | Supplies ≤10 mA; short-circuit protected; requires 1 µF high-frequency bypass for stability | RT/CT | Oscillator timing interface | Accepts external R (5–100 kΩ) and C (470 pF–4.7 nF) to set frequency and max duty cycle |
| GND | Signal ground reference | Common return for error amp, sense, and logic; separate from PGND in 16-pin variant |
| FB | Voltage feedback input | Connects to opto-isolator emitter in isolated designs; sets output regulation point via error amplifier |
| COMP | Error amplifier output | Drives PWM comparator; sinks up to 6 mA; interfaces with external compensation network |
| ISENSE | Current sense input | Accepts ≤1 V peak signal from sense resistor; triggers pulse-by-pulse current limit |
| OUTPUT | Gate driver output | 1 A totem-pole stage; drives MOSFET gate directly; low saturation voltage (<0.4 V @ 20 mA) |
| PGND | Power ground | Return path for gate driver current; enables star grounding to reduce noise coupling into signal ground |
Key Features
| Feature | Design Value |
|---|---|
| Pulse-by-pulse current limiting | Enables robust overcurrent protection without latch-up; allows magnetic component optimization |
| Trimmed oscillator discharge current | 8.3 mA tolerance ensures consistent max duty cycle across temperature and process variation |
| Automatic feedforward compensation | Improves line regulation response without external components or complex loop design |
| High-current totem-pole output | 1 A drive capability eliminates need for external gate driver in ≤100 W applications |
| Internally-trimmed bandgap reference | 5.0 V ±1% over temperature enables accurate feedback without external voltage dividers |
Applications
| AC/DC Adapter | Industrial DC-DC Converter |
|---|---|
Use Scenario: Universal-input (85–265 VAC) 12 V / 4.3 A flyback adapter powering networking equipment. IC Role / Device Role / Timing Role: Primary-side PWM controller implementing peak-current-mode control with opto-coupled voltage feedback. Use Value: Low start-up current (<0.5 mA) minimizes dissipation in high-voltage start resistor; 16 V UVLO ensures clean startup after rectified bulk capacitor reaches safe operating voltage. | Use Scenario: 24 V input to 5 V / 10 A isolated forward converter in factory automation PLC power module. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller regulating duty cycle via primary current sensing and secondary voltage feedback. Use Value: 1 A gate drive directly switches 600 V MOSFETs; trimmed oscillator discharge enables stable 45% max duty cycle required for forward topology. |
| Battery Charger PSU | LED Driver Power Stage |
Use Scenario: 12 V lead-acid battery charger with constant-current/constant-voltage profile powered from 120 VAC. IC Role / Device Role / Timing Role: Off-line flyback controller managing primary-side current limiting and output voltage regulation via TL431 + opto feedback. Use Value: Undervoltage lockout with hysteresis prevents erratic operation during brownout; pulse-by-pulse limiting protects transformer and MOSFET during CC phase transitions. | Use Scenario: Constant-current LED driver for street lighting using 350 VDC bus and multiple series-connected LED strings. IC Role / Device Role / Timing Role: High-voltage flyback controller regulating LED current via primary-side sensing and secondary-side feedback. Use Value: 500 kHz max switching frequency enables small EMI filter and transformer; 8.3 mA trimmed oscillator discharge ensures consistent dimming resolution across production units. |
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 |
|---|---|---|---|
| UC3842BDWTR | Same pinout and function; wider operating temperature range (0°C to 70°C vs –40°C to 85°C); lower UVLO (14.5 V ON / 8.5 V OFF) | Suitable for commercial-grade, non-industrial ambient environments only | Select UC3842BDWTR only if ambient temperature stays within 0–70°C and lower UVLO threshold aligns with system bias design |
| TL494CDR | Dual-output, adjustable dead time, voltage-mode control; no integrated current sense comparator or 1 A gate driver | Requires external current sensing and gate buffering; better suited for push-pull or half-bridge topologies | Choose TL494CDR when dual-output timing, programmable dead time, or voltage-mode control is required - not for direct UC2842ADWTRG4 replacement |
Compared with UC3842BDWTR and TL494CDR, UC2842ADWTRG4 delivers higher temperature rating, tighter UVLO hysteresis, and integrated current-mode control - making it optimal for ruggedized off-line and industrial DC-DC converters where reliability under variable line conditions is critical.
Availability
UC2842ADWTRG4 is available at Aetrix Electronics and suitable for AC/DC adapters, industrial DC-DC converters, and battery-operated power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for UC2842ADWTRG4 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 UCx84xA product line was engineered specifically for cost-sensitive, high-reliability current-mode switch-mode power supplies - emphasizing low start-up current, precise oscillator control, and robust gate drive in standard surface-mount packages.
FAQ
What is the maximum operating temperature for UC2842ADWTRG4?
The UC2842ADWTRG4 has a specified operating free-air temperature range of –40°C to +85°C. This rating applies across all electrical specifications in the datasheet and is validated per JEDEC JESD22-A104. Operation beyond this range may result in degraded performance or reliability loss. The device's thermal metrics (RθJA = 73.6°C/W for DW package) support sustained operation at full load within this envelope when PCB layout follows TI's recommended copper pour and thermal vias guidelines.
Does UC2842ADWTRG4 support duty cycles above 50%?
Yes, UC2842ADWTRG4 supports up to 100% duty cycle in UC2842A/UC2843A variants. However, stable operation above 50% requires external slope compensation injected into the ISENSE pin to prevent subharmonic oscillation. The datasheet recommends resistively summing a fraction of the oscillator ramp (from RT/CT node) with the current sense signal - a technique validated in TI's SLUS224H application notes and typical flyback schematics.
How does the UVLO behavior of UC2842ADWTRG4 differ from UC3842A?
UC2842ADWTRG4 features a 16 V turn-on / 10 V turn-off UVLO threshold with 6 V hysteresis, optimized for off-line applications with high-voltage bulk capacitors. In contrast, UC3842A uses a lower 14.5 V / 8.5 V threshold suited for commercial-grade 120 VAC-only systems. This difference ensures UC2842ADWTRG4 remains disabled until bulk voltage stabilizes above 16 V - preventing premature startup and gate driver instability during AC line sag or cold start.
Can UC2842ADWTRG4 drive a MOSFET directly without an external gate driver?
Yes, UC2842ADWTRG4 integrates a 1 A totem-pole output stage capable of directly driving the gate of medium-power MOSFETs used in ≤100 W flyback or forward converters. Its output can source and sink up to 1 A, with low saturation voltages (≤0.4 V @ 20 mA). For higher gate charge devices or faster switching, a series gate resistor (e.g., 10–22 Ω) is still recommended to damp ringing and limit peak current.
What is the purpose of the PGND pin on UC2842ADWTRG4?
The PGND pin on UC2842ADWTRG4 provides a dedicated return path for the high-current gate driver output, separating power ground current from signal ground (GND). This enables star grounding at the controller, reducing noise coupling into the error amplifier and current sense circuitry - a critical layout practice for stable current-mode control in noisy industrial power environments.
UC2842ADWTRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- UCx84xA
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Programmable:
- -
- Applications:
- PWM Controller
- Voltage - Input:
- -0.3V ~ 6.3V
- Voltage - Supply:
- 10V ~ 30V
- Current - Supply:
- 11 mA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
UC2842ADWTRG4 FAQ
1.How can I place an order for UC2842ADWTRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UC2842ADWTRG4 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 UC2842ADWTRG4 reliable?
The price and inventory of UC2842ADWTRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2842ADWTRG4 is usually 5 days.
3.What payment methods are accepted for UC2842ADWTRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2842ADWTRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC2842ADWTRG4?
UC2842ADWTRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC2842ADWTRG4 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 UC2842ADWTRG4?
For technical support, including UC2842ADWTRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2842ADWTRG4 requirements.
6.How does Aetrix verify that UC2842ADWTRG4 is sourced from the original manufacturer or authorized distributors?
All UC2842ADWTRG4 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 UC2842ADWTRG4 meets industry standards.
7.What is the process for return or replacement of UC2842ADWTRG4?
All UC2842ADWTRG4 units undergo pre-shipment inspection (PSI). If there is an issue with UC2842ADWTRG4, 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 UC2842ADWTRG4 part is unused and in its original packaging.
Return procedure for UC2842ADWTRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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