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STMicroelectronics E-UC2844BN
- Part No.:
- E-UC2844BN
- Manufacturer:
- STMicroelectronics
- Category:
- DC DC Switching Controllers
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
E-UC2844BN.pdf
- Description:
- IC REG CTRLR PWM CM 8-MINIDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,446
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Product details
Overview
E-UC2844BN from STMicroelectronics is a high-performance current-mode PWM controller IC designed for off-line and DC-DC fixed-frequency power supplies. It features a trimmed oscillator guaranteed at 250 kHz, internal toggle flip-flop limiting maximum duty cycle to <50%, UVLO thresholds of 16 V (on) / 10 V (off), and a totem-pole output capable of ±1 A peak drive current - enabling direct N-channel MOSFET gate control in flyback and forward converters.
For engineers reviewing the E-UC2844BN datasheet, E-UC2844BN pinout, E-UC2844BN application, or E-UC2844BN equivalent, this device is selected for cost-sensitive AC/DC adapters, auxiliary power supplies, and industrial SMPS where precise duty-cycle limitation, cycle-by-cycle current limiting, and low-startup-current operation (<0.5 mA) are required.
Technical Context
The E-UC2844BN implements current-mode control with automatic feed-forward compensation and latching PWM for robust cycle-by-cycle current limiting. Its internal oscillator uses RT/CT programming and guarantees 250 kHz frequency with ±3% variation over temperature and supply voltage.
A dedicated toggle flip-flop blanks the output every other clock cycle, enforcing a hard 47–50% maximum duty cycle - distinguishing it from UC2842B/3B and enabling stable operation in topologies requiring strict duty-cycle constraints, such as isolated forward converters with synchronous rectification.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 250 kHz (guaranteed at Tj = 25°C; supports up to 500 kHz with external RT/CT) |
| Max Duty Cycle | 47–50% (enforced by internal toggle flip-flop; prevents transformer saturation in forward topologies) |
| UVLO Threshold | 16 V turn-on / 10 V turn-off (optimized for universal AC input offline applications) |
| Output Drive | ±1 A peak sink/source (directly drives N-MOSFET gates without external buffer) |
| Reference Voltage | 5.00 V ±50 mV (internally trimmed; powers RT/CT network and provides stable error amp bias) |
| Start-up Current | <0.5 mA at Vi = 14 V (reduces auxiliary winding losses in self-biased SMPS) |
| Current Sense Gain | 3.0 V/V ±5% (converts sense resistor voltage to precise 1 V trip threshold at pin 3) |
Pinout & Package
E-UC2844BN is housed in an 8-pin MiniDIP package (body width 7.95–9.75 mm, lead pitch 2.54 mm), suitable for through-hole PCB assembly and legacy power supply designs requiring mechanical robustness and thermal margin (RθJA = 100 °C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (COMP) | Error amplifier output | Provides access to EA output for loop compensation via external RC network |
| 2 (VFB) | Inverting input of error amplifier | Connected to output voltage divider; sets regulation point via 2.5 V internal reference |
| 3 (ISENSE) | Current sense comparator input | Accepts voltage from primary-side sense resistor; terminates switch conduction at 1 V threshold |
| 4 (RT/CT) | Oscillator timing node | Resistor to VREF and capacitor to GND set frequency and discharge slope for PWM clock |
| 5 (GROUND) | Signal and power ground | Single-point return for control logic, reference, and current sense circuits |
| 6 (OUTPUT) | Totem-pole gate driver output | Sources/sinks up to 1 A; low-state during UVLO ensures MOSFET remains off at startup |
| 7 (Vi / VCC) | Supply input | Operates from 10–30 V; internal zener clamps at 36 V; powers all internal circuitry |
| 8 (VREF) | 5 V precision reference output | Supplies charging current to CT via RT; load-regulated to ±25 mV over 1–20 mA |
Key Features
| Feature | Design Value |
|---|---|
| Latched PWM with cycle-by-cycle current limit | Prevents secondary overcurrent events from propagating; resets only on next clock edge |
| Internally trimmed 5 V reference | Eliminates need for external reference IC; maintains ±1% accuracy over line/load/temp |
| Under-voltage lockout with hysteresis | 16 V turn-on / 10 V turn-off ensures clean start-up and brown-out immunity in unregulated inputs |
| High-current totem-pole output stage | Drives 1000 pF gate capacitance with <150 ns rise/fall time; reduces external driver BOM |
| Automatic feed-forward compensation | Compensates for input voltage variations in real time, improving transient response in offline PSUs |
Applications
| AC/DC Adapter Power Supply | Industrial Auxiliary Power Module |
|---|---|
|
Use Scenario: 12 V/1 A isolated flyback converter powering microcontroller peripherals in factory automation equipment. IC Role / Device Role / Timing Role: Primary-side PWM controller generating gated 250 kHz drive signal with 48% max duty cycle to prevent core reset failure. Use Value: Internal UVLO and low 0.4 mA start-up current enable reliable cold-start from 85–265 VAC input without auxiliary winding complexity. |
Use Scenario: 5 V/2 A forward converter supplying isolated I/O interface power in PLC backplane modules. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller enforcing strict 50% duty cycle to avoid transformer saturation under variable load. Use Value: Toggle flip-flop architecture eliminates need for external duty-cycle clamp circuitry, reducing component count and layout area. |
| LED Driver for Street Lighting | Telecom Wall Adapter |
|
Use Scenario: Constant-current 36 V/700 mA LED driver using primary-side sensing in outdoor-rated enclosure. IC Role / Device Role / Timing Role: Current-mode controller regulating LED string current via primary-side sense resistor and error amplifier feedback. Use Value: 3.0 V/V current sense gain enables accurate 1 V threshold detection across wide temperature range (−40°C to +125°C). |
Use Scenario: Dual-output (5 V + 12 V) wall adapter for VoIP phone with standby power <300 mW. IC Role / Device Role / Timing Role: Main controller managing primary switch; integrated 5 V reference powers optocoupler bias and feedback circuitry. Use Value: 5.00 V ±50 mV reference stability ensures consistent feedback accuracy across input line and temperature variations. |
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 |
|---|---|---|---|
| UC3844BN | Same pinout and electrical specs; rated for 0°C to +70°C ambient (vs. −40°C to +150°C for UC2844BN) | Not qualified for extended temperature industrial or automotive environments | Select UC3844BN only for commercial-grade consumer power supplies with limited thermal requirements. |
| TL494CN | Fixed-frequency voltage-mode controller; dual-output, adjustable dead-time; no built-in current sense comparator | Requires external current-sense amplifier and slope compensation for current-mode operation | Choose TL494CN when dual-output push-pull or full-bridge topology is needed, not for single-switch current-mode flyback. |
Compared with UC3844BN, E-UC2844BN offers wider operating temperature range and higher reliability for industrial deployment; versus TL494CN, it delivers integrated current-mode control with fewer external components but lacks dual-output flexibility.
Availability
E-UC2844BN is available at Aetrix Electronics and suitable for AC/DC adapters, industrial auxiliary power modules, and LED drivers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for E-UC2844BN 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, and microcontroller solutions for industrial, automotive, and consumer markets.
E-UC2844BN belongs to the UCx84xB family of current-mode PWM controllers - engineered specifically for cost-effective, high-reliability offline and DC-DC switching power supplies with minimal external component count.
FAQ
What is the maximum allowable oscillator frequency for E-UC2844BN?
The E-UC2844BN supports oscillator frequencies up to 500 kHz using external RT/CT components. The internal oscillator is guaranteed at 250 kHz across temperature and supply voltage, with typical variation of ±3% under specified conditions (RT = 6.2 kΩ, CT = 1 nF). Operation beyond 500 kHz is not characterized and may compromise latch timing or current-sense accuracy.
Does E-UC2844BN require external slope compensation?
No - slope compensation is not required for E-UC2844BN in most standard flyback configurations due to its inherent current-mode architecture and internal compensation design. However, slope compensation becomes necessary in continuous-conduction-mode forward or boost converters operating above 50% duty cycle, where subharmonic oscillation may occur without added ramp injection.
Can E-UC2844BN directly drive a 1000 pF MOSFET gate?
Yes - the totem-pole output stage delivers ±1 A peak current with 50–150 ns rise/fall times into 1 nF capacitive load, making it fully capable of driving MOSFET gates up to 1000 pF without external buffering. Layout best practices (short traces, local bypassing at pin 5, and Kelvin grounding) are essential to maintain switching integrity and minimize shoot-through risk.
How does the UVLO hysteresis improve system reliability?
The 6 V hysteresis (16 V turn-on / 10 V turn-off) prevents oscillatory startup during marginal input conditions, such as brown-outs or weak auxiliary windings. This ensures the controller remains fully disabled until sufficient bus voltage is established, avoiding partial switching that could overheat the MOSFET or cause erratic regulation before stable operation is achieved.
E-UC2844BN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Type:
- Transistor Driver
- Function:
- 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:
- Through Hole
- Supplier Device Package:
- 8-Mini DIP
E-UC2844BN FAQ
1.How can I place an order for E-UC2844BN through Aetrix?
Please submit a Request for Quotation (RFQ) for E-UC2844BN 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 E-UC2844BN reliable?
The price and inventory of E-UC2844BN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for E-UC2844BN is usually 5 days.
3.What payment methods are accepted for E-UC2844BN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for E-UC2844BN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for E-UC2844BN?
E-UC2844BN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your E-UC2844BN 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 E-UC2844BN?
For technical support, including E-UC2844BN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your E-UC2844BN requirements.
6.How does Aetrix verify that E-UC2844BN is sourced from the original manufacturer or authorized distributors?
All E-UC2844BN 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 E-UC2844BN meets industry standards.
7.What is the process for return or replacement of E-UC2844BN?
All E-UC2844BN units undergo pre-shipment inspection (PSI). If there is an issue with E-UC2844BN, 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 E-UC2844BN part is unused and in its original packaging.
Return procedure for E-UC2844BN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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