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STMicroelectronics E-UC3843BD1013TR
- Part No.:
- E-UC3843BD1013TR
- Manufacturer:
- STMicroelectronics
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
E-UC3843BD1013TR.pdf
- Description:
- IC REG CTRLR BOOST/FLYBACK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,774
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Product details
Overview
E-UC3843BD1013TR from STMicroelectronics is a high-performance current-mode PWM controller IC designed for fixed-frequency DC-DC and off-line power supplies. It features a trimmed oscillator guaranteed at 250 kHz, latching PWM for cycle-by-cycle current limiting, internal 5 V reference with ±20 mV line regulation, and under-voltage lockout with 8.4 V turn-on / 7.6 V turn-off thresholds - enabling reliable start-up in low-input-voltage applications such as AC-DC adapters and industrial SMPS.
For engineers reviewing the E-UC3843BD1013TR datasheet, E-UC3843BD1013TR pinout, E-UC3843BD1013TR application, or E-UC3843BD1013TR equivalent, key selection criteria include UVLO threshold compatibility, duty cycle range (up to 100%), peak output drive capability (±1 A), oscillator frequency stability over temperature, and error amplifier bandwidth (1 MHz typical) for loop compensation in current-mode flyback or forward converters.
Technical Context
The UC3843B implements current-mode control using an internal PWM latch, oscillator with RT/CT programmable frequency up to 500 kHz, and a high-gain error amplifier (90 dB open-loop gain) with 1 MHz unity-gain bandwidth. Its current sense comparator features 3 V/V gain and 150 ns delay, enabling precise peak-current limiting.
UVLO hysteresis (0.8 V) ensures clean start-up and shutdown; the totem-pole output stage delivers ±1 A peak current to directly drive N-channel MOSFET gates. The 5 V reference provides 1 mA sourcing capability and exhibits ≤0.2 mV/°C temperature drift, supporting stable feedback network biasing across –40°C to +150°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | Guaranteed 250 kHz at Tj = 25°C; supports 50–500 kHz via RT/CT tuning for flexible switching speed selection. |
| UVLO Threshold | 8.4 V (turn-on) / 7.6 V (turn-off); enables reliable operation in low-input-voltage DC-DC converters. |
| Max Duty Cycle | 96% typical, up to 100%; supports high step-down ratio topologies without external duty cycle clamping. |
| Output Drive | ±1 A peak sink/source; sufficient to drive gate capacitance of medium-power MOSFETs without buffer stage. |
| Error Amp GBW | 1 MHz typical; enables stable Type II/III compensation for current-mode loops with fast transient response. |
| Reference Voltage | 5.00 V ±100 mV over line/load/temp; powers RT/CT network and provides precision bias for feedback divider. |
| Current Sense Gain | 3.0 V/V ±5%; converts sensed resistor voltage to precise PWM trip point for accurate peak-current control. |
| Start-up Current | ≤0.5 mA at Vi = 6.5 V; minimizes auxiliary supply losses in high-efficiency adapter designs. |
Pinout & Package
Package: SO8 (Small Outline Integrated Circuit, 150 °C/W thermal resistance, JEDEC MS-012AC compliant).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - COMP | Error amplifier output | Provides high-impedance node for external Type II/III compensation network; directly connects to feedback loop integrator. |
| 2 - VFB | Inverting input of error amplifier | Receives voltage-divided output signal; sets regulation setpoint when referenced to internal 2.5 V virtual ground. |
| 3 - ISENSE | Current sense comparator input | Accepts voltage from primary-side current-sense resistor; triggers PWM latch reset at programmed peak current threshold. |
| 4 - RT/CT | Oscillator timing interface | Connects external resistor (RT) to VREF and capacitor (CT) to GND to program switching frequency and max duty cycle. |
| 5 - GROUND | Power and signal common reference | Single-point ground for control circuitry and power stage return; critical for noise immunity in current-mode sensing. |
| 6 - OUTPUT | Totem-pole gate driver output | Drives N-MOSFET gate directly; logic-high = ~13.5 V, logic-low = ~0.4 V at 20 mA load; supports fast MOSFET switching. |
| 7 - VCC | Supply input | Accepts 7.6–30 V DC; powers internal bias, oscillator, and logic; includes UVLO protection and self-limiting current. |
| 8 - VREF | 5 V precision reference output | Supplies stable 5 V at up to 20 mA; used to bias RT/CT network and optional optocoupler circuits in isolated designs. |
Key Features
| Feature | Design Value |
|---|---|
| Latching PWM architecture | Ensures single-pulse-per-cycle current limiting, preventing subharmonic oscillation in continuous conduction mode. |
| Internally trimmed 5 V reference | ±100 mV accuracy over temperature and line; eliminates need for external reference in most feedback configurations. |
| Low start-up current (≤0.5 mA) | Reduces auxiliary winding size and losses in flyback converters; improves light-load efficiency. |
| High-current totem-pole output (±1 A) | Eliminates need for external gate driver in <100 W applications; supports fast MOSFET turn-on/turn-off transitions. |
| Automatic feed-forward compensation | Uses VCC variation to modulate oscillator ramp slope, improving line transient rejection without extra components. |
| Under-voltage lockout with hysteresis | Prevents erratic operation during brown-out; 0.8 V hysteresis avoids chatter near threshold during input sag. |
Applications
| AC-DC Adapter | Flyback SMPS |
|---|---|
|
Use Scenario: 5–24 V output, 10–65 W universal-input offline power supply for consumer electronics. IC Role / Device Role / Timing Role: Primary-side PWM controller implementing current-mode flyback regulation with optocoupler feedback. Use Value: UVLO threshold (8.4 V) allows reliable start-up from rectified 90 VAC; 250 kHz operation reduces transformer size and EMI filter cost. |
Use Scenario: Isolated 12 V/2 A industrial power module with wide input range (8–36 VDC). IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller managing primary switch timing, current limit, and soft-start sequencing. Use Value: ±1 A output drives 500 V/1 A MOSFET directly; 1 MHz error amp bandwidth enables tight regulation under dynamic load steps. |
| LED Driver | DC-DC Boost Converter |
|
Use Scenario: Constant-current LED driver for signage lighting with 36 V output and 700 mA load. IC Role / Device Role / Timing Role: Peak-current-mode controller regulating boost-stage MOSFET to maintain LED string current. Use Value: 3 V/V current sense gain enables accurate 50 mΩ sense resistor use; low 0.5 mA start-up current extends hold-up time. |
Use Scenario: 12 V to 24 V boost converter for automotive subsystems with battery input (9–16 V). IC Role / Device Role / Timing Role: High-side switch controller managing inductor current ramp and output voltage regulation. Use Value: 100% max duty cycle supports high conversion ratios; 5 V reference powers external op-amp feedback circuitry. |
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 |
|---|---|---|---|
| UC3842BD1013TR | Higher UVLO (16 V on / 10 V off); no low-voltage start capability. | Suitable only for universal-input or high-line AC-DC where ≥16 V startup is guaranteed. | Select when operating from rectified 180–264 VAC inputs; avoid in low-line or DC-DC applications. |
| NCP1200DR2G | Fixed 65 kHz frequency; built-in soft-start; lower start-up current (100 µA); no adjustable oscillator. | Targeted at cost-sensitive, low-power adapters; lacks RT/CT flexibility and high-frequency capability. | Choose for <15 W applications requiring minimal BOM count and inherent soft-start; not suitable for >200 kHz designs. |
Compared with UC3842BD1013TR, E-UC3843BD1013TR enables lower-input operation and higher duty cycles, while NCP1200DR2G trades programmability for integration and ultra-low start-up current - making each optimal for distinct input voltage ranges and power levels.
Availability
E-UC3843BD1013TR 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 consistent parametric performance across manufacturing lots.
Supply support for E-UC3843BD1013TR 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.
E-UC3843BD1013TR belongs to the UC384xB family of current-mode PWM controllers, engineered for cost-effective, high-reliability switch-mode power supplies in consumer, industrial, and computing applications.
FAQ
What is the maximum recommended operating frequency for E-UC3843BD1013TR?
The device supports oscillator frequencies up to 500 kHz via external RT/CT configuration, though the datasheet guarantees 250 kHz at 25°C. At higher frequencies, propagation delays and gate drive slew rates may reduce effective duty cycle range and require careful PCB layout to minimize noise coupling into the ISENSE pin.
Can E-UC3843BD1013TR drive a P-channel MOSFET directly?
No - the OUTPUT pin is a totem-pole stage optimized for sinking current into an N-channel MOSFET gate. Driving a P-channel device would require level-shifting circuitry or an external inverter, as the output does not provide high-side source capability or rail-to-rail swing above VCC.
How does the automatic feed-forward compensation work in this IC?
It modulates the oscillator's ramp amplitude proportionally to VCC variations, effectively scaling the current-sense threshold to counteract input voltage changes - improving line regulation without adding external components or altering the error amplifier loop.
Is external slope compensation required when using E-UC3843BD1013TR in continuous conduction mode?
Yes - for duty cycles exceeding 50% in CCM, external ramp injection (e.g., via CT pin coupling) is necessary to prevent subharmonic oscillation. The IC lacks internal slope compensation; design guidance is provided in Figure 18 of the datasheet using RSLOPE resistors and timing capacitor derivatives.
E-UC3843BD1013TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Digi-Reel®
- 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
E-UC3843BD1013TR FAQ
1.How can I place an order for E-UC3843BD1013TR through Aetrix?
Please submit a Request for Quotation (RFQ) for E-UC3843BD1013TR 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-UC3843BD1013TR reliable?
The price and inventory of E-UC3843BD1013TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for E-UC3843BD1013TR is usually 5 days.
3.What payment methods are accepted for E-UC3843BD1013TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for E-UC3843BD1013TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for E-UC3843BD1013TR?
E-UC3843BD1013TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your E-UC3843BD1013TR 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-UC3843BD1013TR?
For technical support, including E-UC3843BD1013TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your E-UC3843BD1013TR requirements.
6.How does Aetrix verify that E-UC3843BD1013TR is sourced from the original manufacturer or authorized distributors?
All E-UC3843BD1013TR 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-UC3843BD1013TR meets industry standards.
7.What is the process for return or replacement of E-UC3843BD1013TR?
All E-UC3843BD1013TR units undergo pre-shipment inspection (PSI). If there is an issue with E-UC3843BD1013TR, 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-UC3843BD1013TR part is unused and in its original packaging.
Return procedure for E-UC3843BD1013TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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