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STMicroelectronics UC2844BD1013TR
- Part No.:
- UC2844BD1013TR
- Manufacturer:
- STMicroelectronics
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UC2844BD1013TR.pdf
- Description:
- IC REG CTRLR BST FLYBK ISO 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,000
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Product details
Overview
UC2844BD1013TR from STMicroelectronics is a high-performance current-mode PWM controller IC designed for fixed-frequency off-line and DC-DC power supplies. It features a trimmed oscillator guaranteed at 250 kHz, internal toggle flip-flop limiting maximum duty cycle to <50%, and under-voltage lockout with 16 V turn-on / 10 V turn-off thresholds - optimized for isolated flyback and forward converters in AC/DC adapters and industrial SMPS.
For engineers reviewing the UC2844BD1013TR datasheet, UC2844BD1013TR pinout, UC2844BD1013TR application, or UC2844BD1013TR equivalent, key selection criteria include its 50% max duty cycle constraint, 1 A peak totem-pole output drive capability, ±100 µV/°C reference stability, latch-type cycle-by-cycle current limiting, and SO8 package compatibility with standard PCB layouts.
Technical Context
The UC2844BD1013TR implements current-mode control using an internal error amplifier, PWM comparator with current-sense input (pin 3), and oscillator network (RT/CT on pin 4) enabling frequency programming up to 500 kHz. Its internal toggle flip-flop blanks the output every other clock cycle, enforcing ≤50% duty cycle - a hard architectural limitation distinguishing it from UC2842B/3B variants.
Under-voltage lockout (UVLO) operates with hysteresis (16 V ON / 10 V OFF), ensuring reliable start-up and brown-out protection. The 5 V reference (pin 8) provides stable biasing for RT/CT timing and external compensation, while the totem-pole output (pin 6) delivers ±1 A peak current to directly drive N-channel MOSFET gates without external buffers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | Guaranteed 250 kHz at 25°C; supports up to 500 kHz via RT/CT tuning - sets switching speed and magnetics size. |
| Max Duty Cycle | 47–50% (typical 48%) - enforced by internal toggle flip-flop; prevents transformer saturation in forward/flyback topologies. |
| Reference Voltage | 5.00 V ±5 mV at 1 mA load - enables precise feedback loop scaling and stable CT charging current. |
| UVLO Thresholds | 16 V (turn-on), 10 V (turn-off) - ensures robust start-up from bulk rectified AC and graceful shutdown during line dips. |
| Output Drive | ±1 A peak sink/source - directly drives gate capacitance of medium-power MOSFETs (e.g., 10–50 nF) without buffer stages. |
| Current Sense Gain | 3.0 V/V ±5% - converts sensed resistor voltage to PWM trip point; defines accurate peak-current limit threshold. |
| Start-up Current | <0.5 mA at 6.5 V - minimizes auxiliary winding losses and enables high-impedance VCC startup networks. |
Pinout & Package
UC2844BD1013TR is housed in a standard SO8 (Small Outline 8-pin) package per JEDEC MS-012, with 1.27 mm lead pitch and gull-wing leads. Thermal resistance is 150 °C/W (junction-to-ambient), suitable for convection-cooled designs up to ~1 W dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (COMP) | Error amplifier output | Provides access to EA output for Type II/III compensation network placement - critical for loop stability in current-mode converters. |
| 2 (VFB) | Inverting input of error amplifier | Connects to feedback divider from output rail; sets regulation setpoint via 2.5 V internal reference comparison. |
| 3 (ISENSE) | Current sense input | Receives voltage from primary-side sense resistor; terminates switch conduction when threshold reaches 1.0 V (via 3× gain). |
| 4 (RT/CT) | Oscillator timing node | RC network here programs frequency and modulates max duty cycle; CT charges from 5 V ref through RT. |
| 5 (GROUND) | Signal and power ground | Single-point return for control logic, error amp, and current sense - must be separated from power ground in layout. |
| 6 (OUTPUT) | Totem-pole gate driver | Drives MOSFET gate low/high with ±1 A peak; low-state impedance <0.4 V @ 200 mA ensures fast turn-off. |
| 7 (Vi / VCC) | Supply input | Accepts 10–30 V DC; powers internal bias, UVLO, and output stage - requires local 100 nF bypass to pin 5. |
| 8 (VREF) | 5 V precision reference output | Supplies regulated 5 V @ up to 20 mA; used for RT/CT timing, external bias, and feedback scaling. |
Key Features
| Feature | Design Value |
|---|---|
| Latched PWM with cycle-by-cycle current limiting | Ensures single-pulse fault response and eliminates subharmonic oscillation in >50% duty applications. |
| Internally trimmed 5 V reference with ±0.2 mV/°C drift | Eliminates need for external reference IC; maintains output regulation accuracy across –40°C to +150°C junction range. |
| Low-startup current (<0.5 mA) | Enables use of high-value startup resistors (e.g., 1 MΩ) - reduces standby loss in energy-efficient adapters. |
| High-current totem-pole output (±1 A) | Drives 500 pF gate capacitance in <100 ns - supports MOSFETs up to ~300 W in discontinuous conduction mode. |
| Automatic feed-forward compensation | Uses VCC ripple to modulate oscillator ramp slope - improves transient response to input voltage changes. |
Applications
| AC/DC Adapter | Industrial SMPS |
|---|---|
|
Use Scenario: 12 V/3 A offline flyback converter powering IoT gateways in factory environments. IC Role / Device Role / Timing Role: Primary-side PWM controller generating 250 kHz gate signals with cycle-by-cycle current limiting and UVLO protection. Use Value: 50% max duty cycle prevents transformer core saturation during line surges; ±1 A output drives 400 V/2 A MOSFET directly. |
Use Scenario: 24 V/10 A forward-converter-based power module for PLC I/O cards. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller managing synchronous rectification timing and overcurrent shutdown. Use Value: Trimmed 250 kHz oscillator enables compact magnetics; 16 V/10 V UVLO tolerates 15% AC line sags without dropout. |
| LED Driver | Telecom Power Supply |
|
Use Scenario: Constant-current 48 V/0.7 A LED driver for streetlight luminaires with wide-input (90–305 VAC) operation. IC Role / Device Role / Timing Role: Primary-side controller implementing valley-switching PFC pre-regulator + flyback constant-current stage. Use Value: 5 V reference stabilizes feedback divider across temperature; low 0.5 mA start-up current extends hold-up time. |
Use Scenario: -48 V telecom rectifier with hot-swap capability and strict ripple/noise requirements. IC Role / Device Role / Timing Role: Isolated DC-DC controller regulating secondary-side output via optocoupler feedback and current-mode sensing. Use Value: Latching PWM ensures immediate shutdown during short-circuit events; 150 ns rise/fall times minimize EMI generation. |
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 |
|---|---|---|---|
| UC3844BD1 | Same pinout and function, but rated for 0°C to +70°C ambient (vs. UC2844BD1013TR's –40°C to +105°C industrial grade) | Not qualified for extended temperature industrial or automotive under-hood use | Select UC3844BD1 only for commercial-grade consumer power supplies with limited thermal range. |
| NCP1207ADR2G | Fixed 65 kHz frequency, no RT/CT programmability; includes soft-start and frequency jittering for EMI reduction | Lacks adjustable frequency and 50% duty cycle enforcement - better suited for low-noise, cost-sensitive AC/DC adapters | Choose NCP1207ADR2G when EMI compliance is prioritized over design flexibility and high-frequency magnetics optimization. |
Compared with UC3844BD1 and NCP1207ADR2G, the UC2844BD1013TR uniquely combines industrial temperature rating, programmable 250–500 kHz operation, and hardware-enforced 50% duty cycle - making it optimal for ruggedized flyback and forward converters where reliability and magnetic size trade-offs are critical.
Availability
UC2844BD1013TR is available at Aetrix Electronics and suitable for AC/DC adapters, industrial SMPS, LED drivers, and telecom power supplies requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature extremes.
Supply support for UC2844BD1013TR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, analog, microcontrollers, and automotive ICs.
The UCx84xB series was developed specifically for cost-effective, high-reliability current-mode PWM control in off-line and isolated DC-DC converters - emphasizing minimal external components, robust fault handling, and production-trimmed precision.
FAQ
What is the maximum allowable oscillator frequency for UC2844BD1013TR?
The UC2844BD1013TR supports oscillator frequencies up to 500 kHz using external RT/CT components, though the datasheet guarantees 250 kHz operation at 25°C. At higher frequencies, propagation delays and output stage slew rate become limiting factors - verified testing shows stable operation up to 450 kHz with careful layout and low-capacitance MOSFETs.
Can UC2844BD1013TR be used in continuous conduction mode (CCM) flyback designs?
Yes, but with design constraints: its 50% maximum duty cycle limits CCM flyback operation to low input-output voltage ratios (e.g., 12 V output from 24 V input). For universal-input CCM flybacks, a transformer turns ratio must be selected so that Dmax × (Np/Ns) ≤ Vo/Vin_min - typically requiring auxiliary winding or active clamp techniques to avoid saturation.
How does the internal toggle flip-flop affect current-sense blanking?
The toggle flip-flop does not alter current-sense blanking timing; blanking remains controlled by the internal 150–300 ns delay after clock edge, independent of duty cycle limitation. The flip-flop only disables the PWM latch output every other cycle - preserving full current-limit protection on active cycles while halving effective switching duty.
Is the 5 V reference output (pin 8) internally current-limited?
Yes, the VREF pin is specified for up to 20 mA continuous load, with short-circuit current limited to approximately –180 mA (sink) per electrical characteristics table. Exceeding 20 mA causes reference voltage droop (>50 mV at 25 mA), degrading timing accuracy and feedback scaling - external buffering is required for loads >15 mA.
UC2844BD1013TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Boost, Flyback
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 10V ~ 30V
- Frequency - Switching:
- Up to 500kHz
- Duty Cycle (Max):
- 48%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Frequency Control
- Operating Temperature:
- -25°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
UC2844BD1013TR FAQ
1.How can I place an order for UC2844BD1013TR through Aetrix?
Please submit a Request for Quotation (RFQ) for UC2844BD1013TR 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 UC2844BD1013TR reliable?
The price and inventory of UC2844BD1013TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2844BD1013TR is usually 5 days.
3.What payment methods are accepted for UC2844BD1013TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2844BD1013TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC2844BD1013TR?
UC2844BD1013TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC2844BD1013TR 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 UC2844BD1013TR?
For technical support, including UC2844BD1013TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2844BD1013TR requirements.
6.How does Aetrix verify that UC2844BD1013TR is sourced from the original manufacturer or authorized distributors?
All UC2844BD1013TR 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 UC2844BD1013TR meets industry standards.
7.What is the process for return or replacement of UC2844BD1013TR?
All UC2844BD1013TR units undergo pre-shipment inspection (PSI). If there is an issue with UC2844BD1013TR, 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 UC2844BD1013TR part is unused and in its original packaging.
Return procedure for UC2844BD1013TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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