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Texas Instruments UC2842AD8G4
- Part No.:
- UC2842AD8G4
- Manufacturer:
- Texas Instruments
- Category:
- Power Supply Controllers, Monitors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UC2842AD8G4.pdf
- Description:
- IC PWM BOOST FLYBACK CM 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:218
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Product details
Overview
UC2842AD8G4 from Texas Instruments is a current-mode PWM controller IC designed for off-line and DC-DC switch-mode power supplies, featuring 16 V UVLO turn-on threshold, <0.5 mA start-up current, 8.3 mA trimmed oscillator discharge current, 5 V ±1% internal reference, and up to 500 kHz operation in an SOIC-8 package for flyback and forward converter control.
For engineers reviewing the UC2842AD8G4 datasheet, UC2842AD8G4 pinout, UC2842AD8G4 application, or UC2842AD8G4 equivalent, this page delivers verified electrical specs, thermal behavior, functional block context, and real-world implementation guidance for industrial PSU, battery-operated converters, and power modules requiring stable peak-current-mode control.
Technical Context
The UC2842AD8G4 implements fixed-frequency peak-current-mode (PCM) control with a 1-MHz error amplifier, pulse-by-pulse current limiting via ISENSE clamped at 1 V, and automatic feedforward compensation for line regulation. Its oscillator uses RT/CT programming with trimmed 8.3 mA discharge current to ensure accurate duty-cycle control up to 100%.
During undervoltage lockout (UVLO), the output remains low and the IC sinks ≥10 mA at ≤1.2 V on VCC while drawing only 0.3–0.5 mA start-up current - enabling efficient high-voltage bootstrap startup in off-line designs without parasitic FET turn-on.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| UVLO Turn-On Threshold | 16 V - ensures reliable startup from rectified AC mains after bulk capacitor charging |
| Start-Up Current | <0.5 mA - reduces power loss in high-voltage start-up resistors for off-line PSUs |
| Oscillator Discharge Current | 8.3 mA (trimmed) - enables precise max duty cycle setting independent of process variation |
| VREF Output | 5.0 V ±1% - provides stable bias for feedback networks and internal comparators |
| Output Drive Capability | ±1 A - directly drives MOSFET gates without external buffer in low-to-mid power converters |
| Max Switching Frequency | 500 kHz - supports compact magnetics and high-density SMPS designs |
| Operating Temperature | –40°C to +85°C - rated for industrial ambient conditions in enclosed power modules |
Pinout & Package
UC2842AD8G4 is housed in an 8-pin SOIC (D) package measuring 4.90 mm × 6.00 mm, with gull-wing leads and standard JEDEC MS-012AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - COMP | Error amplifier output | Low-impedance node (80 dB open-loop gain) driving PWM comparator; sinks up to 6 mA for loop stability |
| 2 - FB | Error amplifier inverting input | Accepts voltage feedback signal; sets output regulation point via resistor divider from VREF |
| 3 - ISENSE | Current sense input | Clamps at 1 V to limit peak primary current; enables cycle-by-cycle protection in flyback/forward topologies |
| 4 - RT/CT | Oscillator timing input | Connects external RT (5–100 kΩ) and CT (470 pF–4.7 nF) to set frequency and max duty cycle |
| 5 - GND | Signal ground reference | Common return for analog circuitry; must be star-connected to avoid noise coupling into COMP/FB |
| 6 - OUTPUT | Totem-pole gate driver | Sources/sinks ±1 A; drives N-channel MOSFET gates directly with 25–150 ns rise/fall times (CL = 1 nF) |
| 7 - VCC | Bias supply input | Accepts 11–30 V; powers internal circuitry and gate driver; includes UVLO hysteresis (16 V ON / 10 V OFF) |
| 8 - VREF | 5-V reference output | Stable 5 V ±1% source; supplies feedback divider and optocoupler LED; short-circuit protected at ~100 mA |
Key Features
| Feature | Design Value |
|---|---|
| Pulse-by-pulse current limiting | Enables robust overcurrent protection without external latches; eliminates need for secondary-side sensing in basic flyback designs |
| Trimmed oscillator discharge current | 8.3 mA tolerance ensures consistent max duty cycle across temperature and process, critical for stable high-frequency operation |
| High-current totem-pole output | ±1 A drive capability allows direct connection to MOSFET gates up to ~500 pF, reducing BOM count and layout complexity |
| Low start-up current (<0.5 mA) | Minimizes dissipation in high-voltage start-up resistors, improving efficiency and thermal margin in universal-input offline PSUs |
| Internally-trimmed bandgap reference | 5.0 V ±1% accuracy over –40°C to +85°C eliminates need for external reference in most applications |
Applications
| Industrial Power Supply | Battery-Operated PSU |
|---|---|
Use Scenario: 24 V input, 12 V/5 A regulated output for PLC I/O modules in factory automation cabinets. IC Role / Device Role / Timing Role: Primary-side current-mode PWM controller managing flyback transformer duty cycle and cycle-by-cycle peak current. Use Value: UVLO hysteresis (16 V ON / 10 V OFF) prevents brownout oscillation during line sags; 500 kHz switching enables small EMI filter components. | Use Scenario: Portable medical device with Li-ion battery input (8–12.6 V) powering isolated 5 V/2 A USB-C output. IC Role / Device Role / Timing Role: DC-DC forward controller regulating output via optocoupled feedback, with tight load transient response. Use Value: Low 0.5 mA start-up current extends battery runtime during standby; 1 V ISENSE clamp ensures predictable current limiting across battery voltage range. |
| Power Module | Off-Line Flyback Converter |
Use Scenario: DIN-rail mounted 48 V/100 W AC-DC module for building management systems. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller implementing primary-side regulation with integrated error amplifier and gate driver. Use Value: 8.3 mA trimmed oscillator discharge enables repeatable 75% max duty cycle across production lots, ensuring consistent power density and thermal performance. | Use Scenario: Universal-input (85–265 VAC) 12 V/4 A wall adapter for consumer electronics. IC Role / Device Role / Timing Role: Peak-current-mode controller using TL431 + optocoupler feedback for secondary-side regulation. Use Value: COMP pin's 80 dB open-loop gain and 1 MHz bandwidth support stable Type II compensation; VREF pin supplies optocoupler LED directly. |
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 |
|---|---|---|---|
| UC3842BD1R2G | Same pinout, but rated for 0°C to +70°C ambient; 15 V UVLO turn-on; higher operating current (11–17 mA) | Designed for commercial-grade, non-industrial environments; less suitable for extended temperature enclosures | Select when cost sensitivity outweighs industrial temp range and lower start-up current requirements |
| TL494CN | 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 for dual-output or voltage-mode designs where independent channel control is needed |
Compared with UC3842BD1R2G and TL494CN, UC2842AD8G4 offers superior industrial temperature rating (–40°C to +85°C), lowest start-up current (<0.5 mA), and integrated current-sense protection - making it optimal for ruggedized, high-efficiency flyback converters where reliability under thermal stress and low-power startup are critical.
Availability
UC2842AD8G4 is available at Aetrix Electronics and suitable for industrial power supplies, battery-operated converters, and power modules requiring stable component supply, long-term lifecycle support, and guaranteed traceability.
Supply support for UC2842AD8G4 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 delivering analog, embedded processing, and power management solutions with focus on reliability, precision, and energy efficiency.
The UCx84xA product line was engineered specifically for cost-sensitive, high-volume current-mode switch-mode power supplies - emphasizing low start-up current, trimmed oscillator accuracy, and robust gate drive for flyback, forward, and DC-DC converter applications.
FAQ
What is the UVLO hysteresis behavior of UC2842AD8G4?
The UC2842AD8G4 features undervoltage lockout with 16 V turn-on and 10 V turn-off thresholds, yielding 6 V hysteresis. During UVLO, the OUTPUT pin stays low and the IC draws only 0.3–0.5 mA, preventing parasitic FET turn-on due to Miller effect. This behavior is confirmed in Section 6.3.4 of the SLUS224H datasheet and applies specifically to UC2842AD8G4 among the UC284xA family.
Can UC2842AD8G4 drive a MOSFET directly without a gate driver IC?
Yes, UC2842AD8G4 can drive N-channel MOSFETs directly: its OUTPUT pin sources and sinks up to ±1 A with 25–150 ns rise/fall times (CL = 1 nF). For typical power MOSFETs with gate charge ≤50 nC, no external driver is required. The UC2842AD8G4 datasheet specifies this capability in Section 4 (Pin Functions) and Section 5.5 (Electrical Characteristics).
What is the maximum duty cycle supported by UC2842AD8G4?
The UC2842AD8G4 supports up to 100% maximum duty cycle, as confirmed in the Device Comparison Table and Section 6.3.5 of the SLUS224H datasheet. This is enabled by its trimmed 8.3 mA oscillator discharge current, which stabilizes timing accuracy across temperature and process variations - a key differentiator from earlier UCx84x generations.
How does UC2842AD8G4 implement current limiting?
UC2842AD8G4 performs pulse-by-pulse current limiting via the ISENSE pin, which accepts a voltage derived from a sense resistor in series with the primary switch. The internal comparator clamps the signal at 1 V, directly limiting peak inductor current per cycle. This function is intrinsic to its peak-current-mode architecture and is documented in Sections 6.3.1 and 6.3.2 of the UC2842AD8G4 datasheet.
Is UC2842AD8G4 compatible with WEBENCH® Power Designer?
Yes, UC2842AD8G4 is fully supported in TI's WEBENCH® Power Designer tool. Users can enter input/output specifications (e.g., 85–265 VAC input, 12 V/4.33 A output) to generate complete schematics, perform electrical and thermal simulations, and export CAD-ready layouts - all validated against the UC2842AD8G4's published electrical characteristics and application guidelines.
UC2842AD8G4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- UCx84xA
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- 8-SOIC
UC2842AD8G4 FAQ
1.How can I place an order for UC2842AD8G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UC2842AD8G4 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 UC2842AD8G4 reliable?
The price and inventory of UC2842AD8G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2842AD8G4 is usually 5 days.
3.What payment methods are accepted for UC2842AD8G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2842AD8G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC2842AD8G4?
UC2842AD8G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC2842AD8G4 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 UC2842AD8G4?
For technical support, including UC2842AD8G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2842AD8G4 requirements.
6.How does Aetrix verify that UC2842AD8G4 is sourced from the original manufacturer or authorized distributors?
All UC2842AD8G4 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 UC2842AD8G4 meets industry standards.
7.What is the process for return or replacement of UC2842AD8G4?
All UC2842AD8G4 units undergo pre-shipment inspection (PSI). If there is an issue with UC2842AD8G4, 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 UC2842AD8G4 part is unused and in its original packaging.
Return procedure for UC2842AD8G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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