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STMicroelectronics UC2843BD1013TR
- Part No.:
- UC2843BD1013TR
- Manufacturer:
- STMicroelectronics
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UC2843BD1013TR.pdf
- Description:
- IC REG CTRLR BOOST/FLYBACK 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,954
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Product details
Overview
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 an internally trimmed 5 V reference, UVLO with 8.4 V turn-on/7.6 V turn-off thresholds, 100% maximum duty cycle capability, oscillator frequency up to 250 kHz (guaranteed), and a totem-pole output capable of ±1 A peak drive current - enabling direct N-channel MOSFET gate driving in flyback and forward converters.
For engineers reviewing the UC2843BD1013TR datasheet, UC2843BD1013TR pinout, UC2843BD1013TR application, or UC2843BD1013TR equivalent, key selection criteria include its low start-up current (<0.5 mA), precise current-sense gain (3.0 V/V), latch-based cycle-by-cycle current limiting, and SO8 package compatibility with standard PCB layouts for cost-sensitive industrial and consumer SMPS designs.
Technical Context
The UC2843BD1013TR implements current-mode control using a dedicated current-sense comparator that terminates switch conduction when the sensed inductor current reaches the error amplifier's output voltage level. Its oscillator uses an external RT/CT network to set frequency and duty cycle, with internal discharge current trimmed to 7.8–8.8 mA for stable timing across temperature.
It integrates a 2.5 V precision error amplifier input reference, 65–90 dB open-loop gain, and 0.7–1 MHz unity-gain bandwidth - supporting stable Type II/III compensation in continuous-conduction-mode topologies. The UVLO circuit includes hysteresis and disables all internal logic until VCC exceeds 8.4 V, ensuring reliable start-up under brownout conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | Guaranteed 250 kHz at 25°C; supports up to 500 kHz with external RT/CT tuning for high-density designs. |
| Reference Voltage | 5.00 V ±50 mV at 1 mA load; internally trimmed for <0.2 mV/°C drift - enables accurate feedback scaling without external DACs. |
| Current Sense Gain | 3.0 V/V (±5%); converts sense resistor voltage directly to PWM trip point - simplifies overcurrent threshold setting. |
| UVLO Threshold | 8.4 V (turn-on) / 7.6 V (turn-off); optimized for low-voltage DC-DC inputs like 12 V bus systems. |
| Output Drive | ±1 A peak sink/source; drives 1000 pF gate capacitance with <150 ns rise/fall - eliminates need for external driver stages. |
| Start-up Current | <0.5 mA at 6.5 V; reduces auxiliary winding losses and enables smaller startup resistors in offline adapters. |
| Error Amp GBW | 0.7–1 MHz; supports stable loop compensation for flyback converters operating up to 250 kHz switching frequency. |
Pinout & Package
UC2843BD1013TR is housed in an SO8 (Small Outline 8-pin) package per JEDEC MS-012, with 1.27 mm lead pitch and surface-mount footprint compatible with automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (COMP) | Error Amplifier Output | Provides compensated feedback signal; connects to RC network for loop stability in current-mode control. |
| 2 (VFB) | Inverting Input of Error Amplifier | Receives scaled output voltage via resistor divider; sets regulation point at 2.5 V reference. |
| 3 (ISENSE) | Current-Sense Input | Accepts voltage from primary-side sense resistor; triggers PWM latch when ≥1.0 V (trip point). |
| 4 (RT/CT) | Oscillator Timing Node | Connects external resistor to VREF and capacitor to GND; programs frequency and max duty cycle. |
| 5 (GROUND) | Signal & Power Ground | Common return for control circuitry and power stage; requires star grounding near pin for noise immunity. |
| 6 (OUTPUT) | PWM Output Driver | Drives N-MOSFET gate directly; sinks/sources up to 1 A peak - supports >300 W flyback designs. |
| 7 (Vi / VCC) | Supply Input | Accepts 8.5–30 V; powers internal bias and logic; UVLO active below 7.6 V. |
| 8 (VREF) | 5 V Reference Output | Supplies charging current to CT via RT; stable 5 V source for external circuitry or sensing. |
Key Features
| Feature | Design Value |
|---|---|
| Latching PWM with cycle-by-cycle current limit | Prevents transformer saturation and MOSFET failure during overload or short-circuit by disabling output until reset. |
| Internally trimmed 5 V reference | ±1% accuracy at 25°C; eliminates external voltage reference IC and reduces BOM count in cost-sensitive adapters. |
| Low start-up current (<0.5 mA) | Reduces dissipation in high-resistance startup networks - enables use of 1 MΩ resistors on 30 V bus without thermal derating. |
| Automatic feed-forward compensation | Compensates for input line variations in real time via oscillator modulation - improves transient response without extra components. |
| High-current totem-pole output | ±1 A drive capability ensures fast MOSFET turn-on/turn-off - minimizes switching losses in 100–250 kHz applications. |
Applications
| AC-DC Adapter | Flyback SMPS |
|---|---|
|
Use Scenario: 12 V/2 A wall adapter for IoT gateways with universal AC input (90–264 VAC). IC Role / Device Role / Timing Role: Primary-side PWM controller implementing current-mode flyback regulation with fixed 65 kHz switching. Use Value: Enables compact design with minimal external parts: single RT/CT network, one sense resistor, and no optocoupler compensation required. |
Use Scenario: Isolated 5 V/3 A power supply for industrial PLC I/O modules. IC Role / Device Role / Timing Role: Current-mode controller managing primary-side switching, current limiting, and soft-start sequencing. Use Value: Latch protection prevents secondary short-circuit damage; 8.4 V UVLO ensures reliable restart after brownouts on 12 V backup rails. |
| DC-DC Converter | LED Driver |
|
Use Scenario: 24 V to 5 V/5 A buck-derived converter for automotive infotainment head units. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller regulating output via primary-side sensing and duty-cycle adjustment. Use Value: 250 kHz guaranteed oscillator allows small magnetics; ±1 A output drives large gate charge MOSFETs without buffer. |
Use Scenario: Constant-current 36 V/350 mA LED driver for commercial signage with dimming interface. IC Role / Device Role / Timing Role: PWM modulator converting analog/digital dim signal into precise current regulation via sense resistor feedback. Use Value: 3.0 V/V current-sense gain enables accurate 100 mΩ sense resistor use - minimizing power loss and thermal stress. |
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 |
|---|---|---|---|
| UC3843BD1 | Same pinout and architecture; wider ambient temp range (0–70°C vs. –25–85°C for UC2843B). | Preferred for commercial-grade equipment where extended industrial temperature is not required. | Select UC3843BD1 if operating ambient stays above 0°C and qualification to MIL-PRF-38535 is unnecessary. |
| NCP1200DR2G | Fixed-frequency current-mode controller with integrated HV startup; no external RT/CT needed; lower start-up current (100 µA). | Better suited for ultra-low-power standby modes; lacks latch protection and 100% duty cycle support. | Choose NCP1200DR2G only when lowest no-load consumption is critical and cycle-by-cycle limiting is not mandatory. |
Compared with UC3843BD1, UC2843BD1013TR offers broader temperature operation and tighter oscillator tolerance; versus NCP1200DR2G, it provides robust latch protection and full-duty-cycle flexibility at the cost of higher standby current and external timing components.
Availability
UC2843BD1013TR is available at Aetrix Electronics and suitable for AC-DC adapters, flyback SMPS, and industrial DC-DC converters requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for 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, and power management applications since 1987.
The UC284xB family was developed specifically for cost-effective, high-reliability current-mode switching power supplies - targeting applications where precision timing, low start-up current, and integrated protection are essential.
FAQ
What is the maximum recommended operating frequency for UC2843BD1013TR?
The UC2843BD1013TR guarantees 250 kHz oscillator operation at 25°C and supports up to 500 kHz with appropriate RT/CT values and layout optimization. At 500 kHz, ensure tight grounding, minimized trace inductance on ISENSE and RT/CT nodes, and use of ceramic timing capacitors to maintain stability and avoid jitter-induced EMI.
Can UC2843BD1013TR drive a P-channel MOSFET directly?
No - UC2843BD1013TR's OUTPUT pin is a totem-pole stage designed to source/sink current into an N-channel MOSFET gate. Driving a P-channel device would require level-shifting circuitry or an external driver, as the IC lacks high-side gate drive capability or bootstrap support.
Does UC2843BD1013TR include soft-start functionality?
Not internally - soft-start must be implemented externally using a capacitor on the COMP pin or via a controlled ramp on the ISENSE pin. Figure 24 in the datasheet shows a standard RC soft-start circuit connecting a 1 µF capacitor from COMP to ground with a 1 MΩ resistor from VREF to COMP.
How does the UVLO hysteresis affect system behavior during brownout conditions?
With 8.4 V turn-on and 7.6 V turn-off, UC2843BD1013TR remains latched off until VCC rises above 8.4 V, preventing erratic restart attempts during marginal input conditions. This 0.8 V hysteresis avoids oscillation near the threshold and ensures clean, single-event shutdown and recovery in 12 V rail systems.
UC2843BD1013TR 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):
- 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
UC2843BD1013TR FAQ
1.How can I place an order for UC2843BD1013TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 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 UC2843BD1013TR reliable?
The price and inventory of UC2843BD1013TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC2843BD1013TR is usually 5 days.
3.What payment methods are accepted for UC2843BD1013TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC2843BD1013TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC2843BD1013TR?
UC2843BD1013TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 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 UC2843BD1013TR?
For technical support, including UC2843BD1013TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC2843BD1013TR requirements.
6.How does Aetrix verify that UC2843BD1013TR is sourced from the original manufacturer or authorized distributors?
All 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 UC2843BD1013TR meets industry standards.
7.What is the process for return or replacement of UC2843BD1013TR?
All UC2843BD1013TR units undergo pre-shipment inspection (PSI). If there is an issue with 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 UC2843BD1013TR part is unused and in its original packaging.
Return procedure for UC2843BD1013TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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