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Texas Instruments UC2849DWG4
- Part No.:
- UC2849DWG4
- Manufacturer:
- Texas Instruments
- Category:
- Power Supply Controllers, Monitors
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
UC2849DWG4.pdf
- Description:
- IC REG CTRLR 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:200
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Product details
Overview
UC2849DWG4 from Texas Instruments is a secondary side average current mode PWM controller IC designed for high-power isolated DC-DC converters. It features 500 kHz oscillator frequency, 85% maximum duty cycle, differential AC switching current sensing, 70 MHz gain-bandwidth product for current error amplifier, and load-sharing capability across up to ten units. It operates over –40°C to +85°C and supports stable regulation in telecom rectifiers and redundant power supplies.
For engineers reviewing the UC2849DWG4 datasheet, UC2849DWG4 pinout, UC2849DWG4 application, or UC2849DWG4 equivalent, key selection considerations include its dual-amplifier architecture for accurate average current control, programmable dead time via RDEAD, CLKSYN bus synchronization, and compatibility with isolated secondary-side sensing topologies requiring precise current balancing.
Technical Context
The UC2849DWG4 implements a two-stage analog control loop: a high-bandwidth (70 MHz GBW) current sense amplifier feeds a dedicated integrating current error amplifier whose sawtooth output provides slope-compensated PWM timing; simultaneously, a voltage error amplifier regulates output voltage via VA+ and VA– inputs. Its dual-rail operation (VEE referenced negative supply, GND as signal ground) enables true differential current sensing across shunt resistors on the secondary side.
Control logic integrates undervoltage lockout (VCC threshold 8.3 V), active-low KILL/ENBL/SEQ inputs, RUN open-collector status output, and SHARE bus interface for master-slave load sharing. Oscillator frequency (450–550 kHz) and max duty cycle (80–90%) are set by external RT, CT, and RDEAD components, with internal clamping at CAO (4 V) and VAO (ILIM-limited).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 450–550 kHz - sets switching speed and magnetic component sizing; typical 500 kHz with CT = 345 pF, RT = 4.53 kΩ |
| Max Duty Cycle | 80–90% - adjustable via RDEAD resistor; determines minimum off-time and peak current handling |
| Current Sense Amp GBW | 7 MHz (Acl = 1) - enables stable closed-loop control up to 1 MHz ripple frequencies |
| Voltage Error Amp Voh | 2.85–3.15 V (ILIM > 3 V) - defines upper clamp for average current command signal |
| Supply Voltage Range | 8–20 V - supports wide-input auxiliary bias rails; UVLO activates below 7.9 V |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade power systems with thermal margin |
| Output Sink/Source | 250 mA - drives gate drivers directly without external buffers in medium-power designs |
Pinout & Package
UC2849DWG4 is housed in a 24-pin SOIC (DW) package with standard JEDEC MS-012 footprint, 1.27 mm pitch, and RoHS-compliant CU-NiPdAu finish. Moisture sensitivity level is Level-2-220°C-1 year.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND | Signal reference ground | Common return for all analog amplifiers, reference, and output stage; not power ground |
| VCC | Positive supply input | Power rail for internal logic and amplifiers; UVLO triggers below 7.9 V |
| VEE | Negative supply input | External negative rail enabling differential current sensing; extends common-mode range |
| OUT | PWM output driver | Push-pull capable of 250 mA sink/source; clamped at 8.5 V for MOSFET gate drive |
| CS+, CS– | Differential current sense inputs | Accepts AC ripple across shunt resistor; uncommitted inputs require external compensation |
| VA+, VA– | Voltage error amp inputs | Direct connection to isolated output voltage divider; VA– is inverting input |
| ILIM | Current limit clamp control | Programs VAO upper clamp voltage (e.g., 3.0 V when tied to VREF) to set max load current |
| RDEAD | Dead time programming | Resistor to OSC sets minimum off-time; TDISCHARGE ≈ 2 × RDEAD × CT |
| CLKSYN | Oscillator sync bus | Bidirectional node for synchronizing multiple UC2849DWG4 units to fastest oscillator |
| SHARE | Load share bus | DC voltage representing average output current; wired in parallel across all units |
| ADJ | Slave reference adjustment | Transconductance amplifier output that raises slave VA+ until current matches master |
| SEQ, ENBL, KILL, RUN | Sequencing & control logic | Enable/disable, sequencing, shutdown, and operational status signals with defined thresholds |
Key Features
| Feature | Design Value |
|---|---|
| Secondary-side average current control | Enables precise load current regulation in isolated topologies without primary-side current transformers |
| Differential AC switching current sensing | Rejects common-mode noise on shunt resistor; supports high-frequency ripple up to 1 MHz |
| Integrated slope compensation | Sawtooth output from current error amplifier inherently compensates for subharmonic oscillation |
| Multi-unit load sharing (up to 10) | SHARE bus and ADJ feedback allow automatic master/slave current balancing without external DACs |
| Oscillator synchronization | CLKSYN bus ensures phase alignment across paralleled controllers for reduced EMI and thermal stress |
| Wide temperature operating range | Specified from –40°C to +85°C supports deployment in industrial and telecom environments |
Applications
| Telecom Rectifier Modules | Redundant Server Power Supplies |
|---|---|
Use Scenario: High-efficiency 48 V DC output modules with N+1 redundancy in central office power plants. IC Role / Device Role / Timing Role: Secondary-side controller regulating output voltage and balancing load current across paralleled modules. Use Value: Enables ±3% current matching between units using SHARE bus, reducing thermal derating and improving system MTBF. | Use Scenario: 12 V/200 A hot-swappable power supplies in blade server chassis with dynamic load steps. IC Role / Device Role / Timing Role: Average current mode controller managing transient response and cross-regulation during CPU burst loads. Use Value: 70 MHz GBW current error amplifier delivers fast load-step recovery (<5 µs) without external compensation. |
| Industrial UPS Systems | Medical Isolated DC-DC Converters |
Use Scenario: Online double-conversion UPS with galvanically isolated battery charger and inverter stages. IC Role / Device Role / Timing Role: Secondary-side controller for battery charging converter ensuring precise constant-current/constant-voltage profiles. Use Value: ILIM-programmable current limit and soft-start via RUN-to-VA+ RC network meet IEC 62368-1 safety startup requirements. | Use Scenario: 5 V/3 A isolated DC-DC for patient-connected monitoring equipment requiring reinforced insulation. IC Role / Device Role / Timing Role: Secondary-side controller implementing creepage/clearance-compliant sensing without optocouplers. Use Value: Differential CS+/CS– inputs eliminate need for isolated current sense amplifiers, reducing BOM count and failure points. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar secondary-side average current mode control applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3849DW | Commercial temperature grade (0°C to +70°C); identical pinout, electrical specs, and block diagram | Not rated for extended industrial temperature range; unsuitable for outdoor or high-ambient deployments | Select UC2849DWG4 when operation beyond 70°C ambient is required; UC3849DW suffices for lab or office environments. |
| UCC38C49D | Enhanced version with improved VREF stability (±0.5% vs ±1%), lower Vio (1 mV vs 3 mV), and tighter oscillator tolerance (±2% vs ±10%) | Higher precision current sharing and better light-load regulation; requires updated compensation network | Choose UCC38C49D for medical or aerospace applications demanding tighter parametric drift; UC2849DWG4 remains optimal for cost-sensitive telecom infrastructure. |
Compared with UC3849DW and UCC38C49D, UC2849DWG4 offers the widest industrial temperature range while retaining full functional compatibility with legacy UC3849 designs-making it the preferred choice for field-deployed power systems where reliability across thermal extremes is critical.
Availability
UC2849DWG4 is available at Aetrix Electronics and suitable for telecom rectifier modules, redundant server power supplies, industrial UPS systems, and medical isolated DC-DC converters requiring stable component supply across long production lifecycles.
Supply support for UC2849DWG4 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 since the 1980s.
The UC2849DWG4 belongs to TI's UCx84x family of current-mode PWM controllers, engineered specifically for high-reliability secondary-side control in isolated switch-mode power supplies where precise current sharing and fast transient response are mandatory.
FAQ
What is the operating temperature range specified for the UC2849DWG4?
The UC2849DWG4 is characterized for operation from –40°C to +85°C ambient temperature. This industrial-grade rating is confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables, distinguishing it from the commercial-grade UC3849 (0°C to +70°C). The device maintains full parameter compliance-including oscillator frequency, current sense amplifier offset, and output drive strength-across this full range when powered within its 8 V to 20 V VCC window.
How does the UC2849DWG4 achieve slope compensation without external components?
The UC2849DWG4 achieves inherent slope compensation through its current error amplifier architecture: the sawtooth waveform at CAO is the amplified and inverted inductor current sensed via the current sense resistor. This internally generated ramp is compared against the PWM comparator threshold, automatically matching the inductor down-slope to the oscillator ramp slope. No external ramp injection circuitry is needed, eliminating component count and layout sensitivity while preventing subharmonic oscillation up to 50% duty cycle.
Can the UC2849DWG4 be used in primary-side control configurations?
No, the UC2849DWG4 is explicitly designed for secondary-side average current mode control and is not suitable for primary-side implementations. Its pin functions-including differential CS+/CS– inputs, SHARE bus, ADJ transconductance amplifier, and VEE-referenced architecture-are optimized for isolated output sensing and multi-unit load sharing. Primary-side control requires different topology support (e.g., UC3843/UC3845), and attempting to repurpose UC2849DWG4 in such roles violates its specified operating conditions and invalidates performance guarantees.
What is the function of the VEE pin on the UC2849DWG4, and how should it be connected?
The VEE pin on the UC2849DWG4 serves as the negative supply rail for all internal amplifiers, enabling true differential current sensing. It may be tied to GND for basic operation, but separating VEE from GND (e.g., applying –0.7 V) extends the common-mode input range of the current sense amplifier to include voltages below signal ground. This configuration reduces offset errors when sensing across low-side shunts and is required for zero-duty-cycle operation when RDEAD is connected to OSC. GND remains the signal reference point regardless of VEE connection.
Does the UC2849DWG4 support synchronization with other UC2849DWG4 units, and how is it implemented?
Yes, the UC2849DWG4 supports oscillator synchronization across multiple units via the CLKSYN pin. Each device's CLKSYN is connected through a 100 pF capacitor to a common bus pulled to GND with a ~10 kΩ resistor. The fastest-running oscillator drives the bus high (3.6 V), forcing slower units to reset their discharge cycle upon detecting the 1.4 V threshold. This ensures phase alignment across up to ten paralleled UC2849DWG4 controllers, reducing EMI peaks and enabling coordinated current sharing-critical for high-density power systems.
UC2849DWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Applications:
- Secondary-Side Controller
- Voltage - Input:
- -
- Voltage - Supply:
- 8V ~ 20V
- Current - Supply:
- 21 mA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
UC2849DWG4 FAQ
1.How can I place an order for UC2849DWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UC2849DWG4 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 UC2849DWG4 reliable?
The price and inventory of UC2849DWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2849DWG4 is usually 5 days.
3.What payment methods are accepted for UC2849DWG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2849DWG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC2849DWG4?
UC2849DWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC2849DWG4 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 UC2849DWG4?
For technical support, including UC2849DWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2849DWG4 requirements.
6.How does Aetrix verify that UC2849DWG4 is sourced from the original manufacturer or authorized distributors?
All UC2849DWG4 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 UC2849DWG4 meets industry standards.
7.What is the process for return or replacement of UC2849DWG4?
All UC2849DWG4 units undergo pre-shipment inspection (PSI). If there is an issue with UC2849DWG4, 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 UC2849DWG4 part is unused and in its original packaging.
Return procedure for UC2849DWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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