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STMicroelectronics E-UC2843BD1013TR
- Part No.:
- E-UC2843BD1013TR
- Manufacturer:
- STMicroelectronics
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
E-UC2843BD1013TR.pdf
- Description:
- IC REG CTRLR BOOST/FLYBACK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,147
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Product details
Overview
E-UC2843BD1013TR from STMicroelectronics is a high-performance current-mode PWM controller IC designed for fixed-frequency DC-DC and off-line power supplies. It features 8.5 V turn-on / 7.9 V turn-off UVLO, ≤50% maximum duty cycle, 250 kHz guaranteed oscillator frequency, ±1 A totem-pole output, and internal 5 V reference with <0.5 mA start-up current - enabling reliable flyback and forward converter control in industrial AC/DC adapters.
For engineers reviewing the E-UC2843BD1013TR datasheet, E-UC2843BD1013TR pinout, E-UC2843BD1013TR application, or E-UC2843BD1013TR equivalent, key selection criteria include UVLO threshold compatibility with low-voltage input rails, duty-cycle limitation for transformer reset safety, current-sense gain accuracy (3.0 V/V), and SO8 thermal performance (Rth j-amb = 150 °C/W).
Technical Context
The UC2843B implements current-mode control using a single-ended PWM latch, where the ISENSE input compares sensed inductor current against an error amplifier-derived ramp reference. Oscillator timing is set externally via RT/CT, supporting operation up to 500 kHz with automatic feed-forward compensation enabled by the VREF output's stable 5 V source.
Its internal architecture includes a trimmed 2.5 V error amplifier reference, latching shutdown logic for cycle-by-cycle current limiting, and a high-current totem-pole driver optimized for N-channel MOSFET gate drive. The 8.5 V / 7.9 V UVLO hysteresis ensures robust start-up under brown-out conditions without external supervision circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | Guaranteed 250 kHz at 25°C; supports 50–500 kHz via RT/CT tuning for flexible switching loss vs. size trade-offs. |
| UVLO Threshold | 8.5 V (on) / 7.9 V (off); enables reliable operation from 9–12 V DC bus inputs without auxiliary bias winding. |
| Max Duty Cycle | ≤50%; enforced by internal toggle flip-flop - prevents transformer saturation in forward/flyback topologies. |
| Current Sense Gain | 3.0 V/V (±5%); converts sense resistor voltage directly to comparator trip point for accurate peak current limiting. |
| Output Drive | ±1 A peak sink/source; drives 1000 pF gate capacitance with <150 ns rise/fall time - sufficient for 500 kHz MOSFET switching. |
| Reference Voltage | 5.00 V ±10 mV at 1 mA; powers RT/CT network and provides stable feedback reference for error amplifier. |
| Start-up Current | <0.5 mA at 6.5 V; allows direct startup from high-impedance auxiliary windings or capacitive dropper supplies. |
Pinout & Package
Package: SO8 (Small Outline Integrated Circuit, 150 °C/W junction-to-ambient thermal resistance). Pin numbering follows standard SO8 top-view layout with 1.27 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - COMP | Error amplifier output | Provides open-collector node for loop compensation network (RC/Zi/Zf) - sets phase margin and bandwidth of current-mode control loop. |
| 2 - VFB | Inverting input of error amplifier | Receives scaled output voltage via resistive divider; regulates output by adjusting duty cycle to maintain 2.5 V at this pin. |
| 3 - ISENSE | Current sense comparator input | Accepts voltage from primary-side sense resistor; terminates switch conduction when signal reaches 1.0 V (trip threshold). |
| 4 - RT/CT | Oscillator timing interface | Connects external resistor to VREF and capacitor to GND; sets fOSC and controls max duty cycle via discharge current (7.8–8.8 mA). |
| 5 - GROUND | Signal and power return | Single-point ground for control logic, error amp, and oscillator - critical for noise immunity in high di/dt environments. |
| 6 - OUTPUT | Gate drive output | Push-pull totem pole; actively drives MOSFET gate high/low - eliminates need for external driver in ≤100 W designs. |
| 7 - VCC | Supply input | Accepts 7.9–30 V unregulated input; powers internal bias, reference, and logic - self-limiting above 30 V. |
| 8 - VREF | 5 V reference output | Supplies regulated 5 V at ≤20 mA; used to bias RT/CT network and optional auxiliary circuits - internally trimmed to ±1%. |
Key Features
| Feature | Design Value |
|---|---|
| Latched PWM with cycle-by-cycle current limiting | Prevents overcurrent damage during fault conditions by forcing immediate shutdown until next clock cycle - no external protection needed. |
| Internally trimmed 5 V reference | Stable ±10 mV tolerance at 1 mA load enables precise RT/CT timing and eliminates external reference IC in cost-sensitive designs. |
| Automatic feed-forward compensation | Uses VREF as oscillator ramp source - inherently compensates for input voltage variations without additional op-amps or components. |
| Low start-up current (<0.5 mA) | Enables direct bootstrap from output winding or capacitive dropper - reduces auxiliary supply complexity in isolated converters. |
| High-current totem-pole output (±1 A) | Drives 10 nC gate charge MOSFETs at 500 kHz without external buffer - simplifies gate drive path and improves EMI performance. |
Applications
| AC/DC Adapter | Flyback SMPS |
|---|---|
Use Scenario: 12 V/2 A wall adapter for IoT sensors with universal 85–265 VAC input. IC Role / Device Role / Timing Role: Primary-side PWM controller enforcing 48% max duty cycle to ensure safe transformer reset and meet EN 61000-3-2 harmonic limits. Use Value: UVLO hysteresis (8.5 V/7.9 V) prevents erratic restart during line sags; 500 kHz capability shrinks magnetics by 4× versus 125 kHz alternatives. |
Use Scenario: Isolated 5 V/3 A medical-grade power supply with reinforced insulation and <300 mW no-load consumption. IC Role / Device Role / Timing Role: Current-mode controller implementing opto-coupled feedback with COMP pin compensation for ±1% output regulation across line/load/temp. Use Value: 3.0 V/V current sense gain enables use of 0.2 Ω sense resistor - minimizing conduction loss while maintaining 100 mV noise margin. |
| Industrial DC/DC Converter | LED Driver (Constant Current) |
Use Scenario: 24 V input to 5 V/10 A board-mounted converter for PLC I/O modules operating at –40°C to +85°C. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller with external RT/CT setting 250 kHz for optimal core loss vs. EMI balance. Use Value: SO8 package with 150 °C/W Rth j-amb sustains full output at 70°C ambient without derating - validated per JEDEC JESD51-2. |
Use Scenario: 36 V constant-current LED driver for street lighting with analog dimming via VFB pin. IC Role / Device Role / Timing Role: Secondary-side current regulator using ISENSE feedback from shunt resistor; VFB adjusted to set LED current. Use Value: 2.5 V error amp reference point enables precise 1% current regulation; latch protection prevents LED string open-circuit damage. |
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 |
|---|---|---|---|
| UC3843BD1013TR | Same pinout and electrical specs; rated for 0°C to +70°C commercial temp range vs. UC2843B's –40°C to +150°C industrial grade. | Not qualified for extended temperature industrial or automotive under-hood use. | Select UC2843B for designs requiring operation below 0°C or above 70°C ambient. |
| NCP1200DR2G | Fixed 65 kHz frequency, no RT/CT programmability; lower start-up current (75 µA); lacks VREF output and COMP pin access. | Suitable only for low-cost, fixed-frequency flyback designs without loop compensation flexibility. | Choose UC2843B when variable frequency, external compensation, or 5 V reference sourcing is required. |
Compared with UC3843BD1013TR, E-UC2843BD1013TR offers extended temperature qualification and higher reliability screening; versus NCP1200DR2G, it delivers design flexibility through programmable frequency, full error amplifier access, and integrated reference - critical for precision-regulated or wide-input-range systems.
Availability
E-UC2843BD1013TR is available at Aetrix Electronics and suitable for AC/DC adapters, flyback SMPS, industrial DC/DC converters, and LED drivers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for E-UC2843BD1013TR 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, delivering silicon solutions for automotive, industrial, power, and embedded applications since 1987.
E-UC2843BD1013TR belongs to ST's legacy UCx84xB current-mode PWM controller product line, engineered specifically for cost-effective, high-reliability offline and DC-DC power conversion in industrial and consumer equipment.
FAQ
What is the maximum recommended operating frequency for E-UC2843BD1013TR?
The device supports oscillator frequencies up to 500 kHz per datasheet Figure 2, confirmed by test condition "Operation to 500kHz is possible" and electrical spec fOSC = 49–275 kHz (typical range). At 500 kHz, RT must be reduced and CT minimized while ensuring stable latch timing and adequate dead time - verified with CL = 1 nF load and 25°C ambient.
Can E-UC2843BD1013TR drive a P-channel MOSFET directly?
No - the OUTPUT pin is a totem-pole stage configured for source/sink into N-channel MOSFET gates. Driving a P-channel requires level-shifting circuitry or an external inverter, as the output does not provide high-side gate drive capability or floating source connection. Its logic-low state pulls to GND, making it unsuitable for direct high-side P-MOS control.
How does the 50% maximum duty cycle affect transformer design in flyback topologies?
The internal toggle flip-flop enforces ≤50% duty cycle to guarantee minimum off-time for transformer demagnetization. This mandates selection of a core with sufficient AL value and air gap to avoid saturation at worst-case input (e.g., 85 VAC) and full load - typically requiring 30–40% more primary turns than a 75% duty cycle controller would need.
Is external slope compensation required when using E-UC2843BD1013TR in continuous conduction mode (CCM)?
Yes - unlike later-generation controllers, UC2843B lacks built-in slope compensation. For CCM flyback or forward converters, an external ramp (e.g., injected into ISENSE via RC network tied to VREF) must be added to prevent subharmonic oscillation when duty cycle exceeds 50%, as specified in Figure 18 of the datasheet.
E-UC2843BD1013TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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):
- 7.6V ~ 30V
- Frequency - Switching:
- Up to 500kHz
- Duty Cycle (Max):
- 96%
- 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
E-UC2843BD1013TR FAQ
1.How can I place an order for E-UC2843BD1013TR through Aetrix?
Please submit a Request for Quotation (RFQ) for E-UC2843BD1013TR 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-UC2843BD1013TR reliable?
The price and inventory of E-UC2843BD1013TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for E-UC2843BD1013TR is usually 5 days.
3.What payment methods are accepted for E-UC2843BD1013TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for E-UC2843BD1013TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for E-UC2843BD1013TR?
E-UC2843BD1013TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your E-UC2843BD1013TR 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-UC2843BD1013TR?
For technical support, including E-UC2843BD1013TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your E-UC2843BD1013TR requirements.
6.How does Aetrix verify that E-UC2843BD1013TR is sourced from the original manufacturer or authorized distributors?
All E-UC2843BD1013TR 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-UC2843BD1013TR meets industry standards.
7.What is the process for return or replacement of E-UC2843BD1013TR?
All E-UC2843BD1013TR units undergo pre-shipment inspection (PSI). If there is an issue with E-UC2843BD1013TR, 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-UC2843BD1013TR part is unused and in its original packaging.
Return procedure for E-UC2843BD1013TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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