My Inquiry
My Account
STMicroelectronics UC3843BD1013TR
- Part No.:
- UC3843BD1013TR
- Manufacturer:
- STMicroelectronics
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UC3843BD1013TR.pdf
- Description:
- IC REG CTRLR BOOST/FLYBACK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:14,431
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
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 an internally trimmed 5 V reference, guaranteed 250 kHz oscillator frequency, under-voltage lockout with 8.4 V turn-on/7.6 V turn-off thresholds, and latching PWM for cycle-by-cycle current limiting. It drives N-channel MOSFETs directly via a totem-pole output capable of ±1 A peak current, and operates up to ~100% duty cycle in continuous conduction mode.
For engineers reviewing the UC3843BD1013TR datasheet, UC3843BD1013TR pinout, UC3843BD1013TR application, or UC3843BD1013TR equivalent, key selection criteria include UVLO threshold compatibility (8.4 V ON / 7.6 V OFF), current-sense gain (3 V/V), error amplifier bandwidth (1 MHz), output drive strength (±1 A), and SO8 package thermal resistance (150 °C/W).
Technical Context
The UC3843BD1013TR implements current-mode control using a voltage-controlled oscillator synchronized to sensed inductor current, enabling automatic feed-forward compensation and stable operation up to 500 kHz. Its internal 5 V reference is trimmed to ±2% over temperature and load, and its error amplifier provides 90 dB open-loop gain with 1 MHz unity-gain bandwidth.
UVLO hysteresis ensures reliable start-up and brown-out recovery, while the latched PWM comparator guarantees precise per-cycle current limiting. The RT/CT oscillator interface allows programmable frequency and duty cycle, and the COMP pin provides direct access to the error amplifier output for custom loop compensation.
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. |
| Reference Voltage | 5.00 V ±2% (4.90–5.10 V) over temperature and load; powers CT timing network and serves as precision feedback reference. |
| UVLO Threshold | 8.4 V turn-on / 7.6 V turn-off; enables reliable start-up in low-input-voltage DC-DC converters. |
| Current Sense Gain | 3.0 V/V (2.85–3.15 V/V); converts sense resistor voltage to precise 1 V trip point for PWM latch activation. |
| Output Drive | ±1 A peak source/sink capability; directly drives gate capacitance of medium-power N-MOSFETs without buffer. |
| Error Amp Bandwidth | 1 MHz unity-gain bandwidth; supports fast transient response in tightly regulated SMPS designs. |
| Start-up Current | <0.5 mA at 6.5 V; minimizes auxiliary supply burden during initial power-up. |
| Max Duty Cycle | 96–100%; supports high step-down ratio topologies like flyback and forward converters. |
Pinout & Package
UC3843BD1013TR is housed in an SO8 (Small Outline 8-pin) package with standard 1.27 mm pitch, 5.0 mm × 6.2 mm body, and 150 °C/W junction-to-ambient thermal resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - COMP | Error amplifier output | Provides high-impedance node for external Type II/III compensation networks; directly connects to PWM latch input. |
| 2 - VFB | Inverting input of error amplifier | Receives scaled output voltage via resistive divider; sets regulation setpoint relative to 2.5 V internal reference. |
| 3 - ISENSE | Current sense comparator input | Accepts voltage from primary-side sense resistor; triggers PWM shutdown when ≥1.0 V (trip point). |
| 4 - RT/CT | Oscillator timing interface | Connects external resistor (RT) to VREF and capacitor (CT) to GND; sets switching frequency and max duty cycle. |
| 5 - GROUND | Signal and power return | Common reference for all analog circuitry and output stage; requires low-inductance PCB layout. |
| 6 - OUTPUT | Totem-pole gate driver | Sources/sinks up to 1 A peak; drives N-MOSFET gate directly; low-state impedance ensures safe FET turn-off. |
| 7 - VCC | Supply input | Accepts 7.6–30 V; powers internal bias, reference, and logic; includes UVLO detection and hysteresis. |
| 8 - VREF | 5 V precision reference output | Supplies 5 V ±2% at up to 20 mA; biases RT resistor and charges CT capacitor in oscillator circuit. |
Key Features
| Feature | Design Value |
|---|---|
| Latching PWM with cycle-by-cycle current limit | Ensures immediate shutdown on overcurrent event; prevents transformer saturation and MOSFET failure. |
| Internally trimmed 5 V reference | ±2% accuracy over temperature and load eliminates need for external reference; reduces BOM count. |
| Automatic feed-forward compensation | Compensates for input line variations in real time without external components; improves load regulation. |
| Low start-up current (<0.5 mA) | Enables use with high-value start-up resistors; reduces power loss and heat in auxiliary supplies. |
| High-current totem-pole output (±1 A) | Drives 1 nF gate capacitance with <150 ns rise/fall times; supports >200 kHz operation without external driver. |
| Trimmed oscillator with guaranteed 250 kHz | Reduces timing component tolerance sensitivity; simplifies EMI filtering and magnetics design. |
Applications
| AC-DC Adapter | Industrial DC-DC Converter |
|---|---|
|
Use Scenario: 12 V/3 A isolated flyback supply for industrial sensors powered from 85–265 VAC mains. IC Role / Device Role / Timing Role: Primary-side PWM controller implementing current-mode regulation, UVLO-based soft-start, and cycle-by-cycle overcurrent protection. Use Value: 8.4 V UVLO enables reliable start-up from rectified AC peaks ≥12 V; 100% duty cycle supports wide input range without auxiliary winding. |
Use Scenario: 24 V to 5 V/10 A synchronous buck converter in PLC I/O module with tight thermal constraints. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller providing gate drive, current sensing, and error amplification for closed-loop output regulation. Use Value: ±1 A output drive eliminates external MOSFET driver; 1 MHz error amp bandwidth enables fast load transient response (<50 µs settling). |
| Telecom Power Supply | LED Driver (Constant Current) |
|
Use Scenario: 48 V input, 12 V/5 A half-bridge DC-DC converter for telecom shelf management systems. IC Role / Device Role / Timing Role: Master PWM controller generating complementary gate signals (with external logic), regulating output via optocoupled feedback. Use Value: COMP pin accessibility enables Type III compensation for high-phase-margin stability; 5 V reference powers optocoupler LED and feedback divider. |
Use Scenario: 36 V to 24 V constant-current LED driver for street lighting with analog dimming interface. IC Role / Device Role / Timing Role: Current-mode controller regulating LED string current via secondary-side sense resistor and error amplifier feedback. Use Value: 3 V/V current sense gain enables accurate 1 A LED current control with 0.33 Ω sense resistor; low 0.5 mA start-up current extends standby efficiency. |
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 |
|---|---|---|---|
| UC3843N | Same electrical specs but in PDIP-8 package; RθJA = 100 °C/W vs. 150 °C/W for SO8; no moisture sensitivity level (MSL) restriction. | Better thermal performance in low-airflow environments; not suitable for automated SMT assembly. | Select when board-level reflow is unavailable or thermal margin is critical and space permits through-hole mounting. |
| TL494CN | Fixed-frequency voltage-mode controller; dual-output, adjustable dead time; no integrated 5 V reference; requires external oscillator components. | Supports push-pull and full-bridge topologies; lacks cycle-by-cycle current limiting and automatic feed-forward. | Choose for dual-output or phase-shifted designs where voltage-mode control suffices and cost-per-function is prioritized. |
Compared with UC3843BD1013TR, UC3843N offers superior thermal dissipation but sacrifices SMT compatibility, while TL494CN provides topology flexibility at the cost of current-mode benefits like inherent slope compensation and faster transient immunity.
Availability
UC3843BD1013TR is available at Aetrix Electronics and suitable for AC-DC adapters, industrial DC-DC converters, and telecom power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for 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, delivering silicon solutions for automotive, industrial, and power management applications.
The UC384xB family was engineered specifically for cost-sensitive, high-reliability current-mode switch-mode power supplies - emphasizing minimal external parts count, robust UVLO behavior, and integrated gate drive for mainstream offline and DC-DC converters.
FAQ
What is the maximum recommended operating frequency for UC3843BD1013TR?
The UC3843BD1013TR supports oscillator frequencies up to 500 kHz with appropriate RT/CT values, though the guaranteed specification is 250 kHz at 25°C. At higher frequencies, propagation delays and gate drive slew rates become limiting factors; design validation above 350 kHz requires careful attention to PCB layout, gate resistor selection, and current-sense noise filtering.
Can UC3843BD1013TR drive a P-channel MOSFET directly?
No - UC3843BD1013TR's OUTPUT pin is a totem-pole stage optimized for sinking current into an N-channel MOSFET gate during turn-off and sourcing current during turn-on. Driving a P-channel device would require level-shifting circuitry or an external inverter, as the IC lacks high-side drive capability or bootstrap support.
How does the UVLO hysteresis affect system reliability in low-input applications?
The 8.4 V turn-on / 7.6 V turn-off hysteresis (0.8 V window) prevents oscillatory startup or shutdown during input voltage sags, such as those caused by line dips or capacitor discharge. This ensures clean, deterministic power sequencing in battery-backed or wide-input-range DC-DC converters without external supervision circuitry.
Is external slope compensation required when using UC3843BD1013TR in continuous conduction mode?
Yes - unlike some newer controllers, UC3843BD1013TR does not integrate slope compensation. For CCM operation above 50% duty cycle, an external ramp signal must be summed into the ISENSE pin to prevent subharmonic oscillation; typical implementation uses a resistor from VREF to ISENSE with RC filtering to match inductor ramp rate.
UC3843BD1013TR 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:
- 0°C ~ 70°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
UC3843BD1013TR FAQ
1.How can I place an order for UC3843BD1013TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 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 UC3843BD1013TR reliable?
The price and inventory of UC3843BD1013TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC3843BD1013TR is usually 5 days.
3.What payment methods are accepted for UC3843BD1013TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC3843BD1013TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC3843BD1013TR?
UC3843BD1013TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 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 UC3843BD1013TR?
For technical support, including UC3843BD1013TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC3843BD1013TR requirements.
6.How does Aetrix verify that UC3843BD1013TR is sourced from the original manufacturer or authorized distributors?
All 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 UC3843BD1013TR meets industry standards.
7.What is the process for return or replacement of UC3843BD1013TR?
All UC3843BD1013TR units undergo pre-shipment inspection (PSI). If there is an issue with 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 UC3843BD1013TR part is unused and in its original packaging.
Return procedure for UC3843BD1013TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
UC3843BD1013TR Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
