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STMicroelectronics E-UC2845BD1013TR
- Part No.:
- E-UC2845BD1013TR
- Manufacturer:
- STMicroelectronics
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
E-UC2845BD1013TR.pdf
- Description:
- IC REG CTRLR BOOST/FLYBACK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,123
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Product details
Overview
E-UC2845BD1013TR from STMicroelectronics is a high-performance current-mode PWM controller IC designed for fixed-frequency DC-DC and off-line power supplies. It features 250 kHz guaranteed oscillator frequency, 47–50% maximum duty cycle (due to internal toggle flip-flop), and under-voltage lockout thresholds of 8.4 V (turn-on) and 7.6 V (turn-off), optimized for low-input-voltage applications such as telecom DC-DC converters and adapter power stages.
For engineers reviewing the E-UC2845BD1013TR datasheet, E-UC2845BD1013TR pinout, E-UC2845BD1013TR application, or E-UC2845BD1013TR equivalent, key selection criteria include UVLO hysteresis, current-sense gain (3.0 V/V), totem-pole output drive capability (±1 A), and SO8 package compatibility with standard PCB layouts for isolated flyback and forward converters.
Technical Context
The UC2845B implements current-mode control using a single-ended PWM architecture with cycle-by-cycle current limiting via an internal latch and comparator. Its oscillator uses RT/CT programming with ±1% frequency tolerance at 25°C and supports operation up to 500 kHz when externally configured.
It integrates a trimmed 5.0 V reference (±1% over temperature), error amplifier with 90 dB open-loop gain and 1 MHz unity-gain bandwidth, and a high-current totem-pole output stage capable of sourcing/sinking 1 A peak - enabling direct gate drive of N-channel MOSFETs without external buffers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 250 kHz guaranteed at 25°C; enables stable switching in compact 30–50 W SMPS designs |
| Max Duty Cycle | 47–50%; enforced by internal toggle flip-flop - prevents subharmonic oscillation in continuous conduction mode |
| UVLO Thresholds | 8.4 V turn-on / 7.6 V turn-off; narrow hysteresis (0.8 V) suits low-voltage DC inputs like 12 V telecom rails |
| Current Sense Gain | 3.0 V/V (±5%); converts sense resistor voltage to precise 1 V trip point for accurate peak-current limiting |
| Output Drive | ±1 A peak sink/source; directly drives MOSFET gates with <150 ns rise/fall times into 1 nF load |
| Reference Voltage | 5.00 V ±1% at 25°C; powers RT/CT timing network and provides stable bias for compensation networks |
| Start-up Current | <0.5 mA at 6.5 V; minimizes auxiliary winding losses in flyback startup circuits |
Pinout & Package
Package: SO8 (Small Outline Integrated Circuit, 150 mil width), RoHS-compliant, surface-mountable with standard reflow profile.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - COMP | Error amplifier output | Provides access to EA output for Type II/III compensation network placement adjacent to IC |
| 2 - VFB | Inverting input of error amplifier | Connects to feedback divider from output rail; sets regulation accuracy and transient response |
| 3 - ISENSE | Current sense input | Accepts voltage from primary-side sense resistor; triggers PWM latch at 1 V threshold for cycle-by-cycle protection |
| 4 - RT/CT | Oscillator timing node | RT to VREF and CT to GND set frequency and max duty cycle; supports 50–500 kHz range |
| 5 - GROUND | Power and signal common | Single-point ground connection required for noise immunity; ties control logic and power return |
| 6 - OUTPUT | PWM output driver | Totem-pole stage sinks/sources up to 1 A; drives MOSFET gate directly with low saturation voltage |
| 7 - VCC | Supply input | Operates from 7.6–30 V; internal zener clamps at 36 V; powers all internal circuitry including reference and oscillator |
| 8 - VREF | 5 V reference output | Supplies regulated 5 V at up to 50 mA; used for RT biasing and optional analog circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Latching PWM with cycle-by-cycle current limit | Prevents transformer saturation and MOSFET failure during overload or short-circuit events |
| Internally trimmed 5.0 V reference | Eliminates need for external reference IC; maintains ±1% accuracy across -40°C to +150°C junction temp |
| Automatic feed-forward compensation | Compensates for line voltage variations in real time, improving load regulation without added components |
| Low start-up current (<0.5 mA) | Reduces auxiliary winding size and losses in flyback converters; enables efficient no-load operation |
| High-current totem-pole output | Drives 1000 pF gate capacitance with <150 ns transitions - reduces MOSFET switching losses |
Applications
| Telecom DC-DC Converters | AC-DC Adapters (Low-Voltage Input) |
|---|---|
|
Use Scenario: Step-down conversion from 12 V or 24 V telecom bus to 3.3 V/5 V logic rails in base station modules. IC Role / Device Role / Timing Role: Primary-side PWM controller regulating output via optocoupler feedback; generates 250 kHz gate drive synchronized to current-sense ramp. Use Value: Narrow UVLO window (8.4 V / 7.6 V) ensures reliable startup and shutdown during brownout conditions on shared telecom backplanes. |
Use Scenario: Compact wall-mounted adapters accepting 9–15 V DC input (e.g., PoE-powered devices) delivering 5 V/2 A. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller implementing flyback topology with primary-side sensing and demagnetization detection. Use Value: 50% max duty cycle prevents subharmonic instability in continuous conduction mode at light loads, improving efficiency and EMI. |
| Industrial Sensor Power Supplies | LED Driver Control Stages |
|
Use Scenario: Isolated 24 V to 5 V/3.3 V supply powering fieldbus transceivers and analog sensor front-ends in PLC I/O modules. IC Role / Device Role / Timing Role: Secondary-side regulated flyback controller using TL431 + optocoupler feedback loop referenced to VFB pin. Use Value: Trimmed 5.0 V reference ensures stable RT/CT timing and error amp biasing across wide industrial temperature range (-40°C to +105°C). |
Use Scenario: Constant-current LED driver for architectural lighting, where input is stabilized 12 V DC from central PSU. IC Role / Device Role / Timing Role: Buck-derived current-mode controller modulating MOSFET duty cycle based on LED string current sensed via shunt resistor. Use Value: 3.0 V/V current sense gain enables use of low-value, low-power sense resistors (e.g., 0.1 Ω), minimizing thermal drift and board space. |
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 |
|---|---|---|---|
| UC3845BN | DIP-8 package; identical electrical specs but through-hole mounting; higher thermal resistance (100 °C/W vs. 150 °C/W) | Suitable for prototyping or legacy through-hole boards; not recommended for high-density SMT production | Select when manual assembly or socket-based testing is required; avoid for thermally constrained layouts |
| TL494CN | Fixed 200 kHz oscillator; dual-output push-pull; no integrated current-sense comparator or UVLO hysteresis | Requires external current sensing and startup circuitry; better suited for half-bridge or full-bridge topologies | Choose only if dual-output gate drive or adjustable dead-time is needed; adds complexity for simple flyback designs |
Compared with UC3845BN, E-UC2845BD1013TR offers superior thermal performance and automated SMT placement; versus TL494CN, it delivers plug-and-play current-mode control with fewer external components and tighter regulation accuracy.
Availability
E-UC2845BD1013TR is available at Aetrix Electronics and suitable for telecom DC-DC converters, low-voltage AC-DC adapters, and industrial sensor power supplies requiring stable component supply, long-term lifecycle support, and consistent SO8 packaging across production batches.
Supply support for E-UC2845BD1013TR 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-UC2845BD1013TR belongs to the UCx84xB family of current-mode PWM controllers, engineered specifically for cost-sensitive, high-reliability offline and DC-DC switch-mode power supplies operating across industrial and telecom environments.
FAQ
What is the maximum operating frequency of E-UC2845BD1013TR?
The device guarantees 250 kHz oscillator frequency at 25°C, but its current-mode architecture supports stable operation up to 500 kHz when RT and CT values are selected per Figure 2 in the datasheet. Frequency stability degrades above 350 kHz due to propagation delays in the internal comparator and latch.
Can E-UC2845BD1013TR drive a MOSFET directly without a gate driver?
Yes - its totem-pole output delivers ±1 A peak current with <1.1 V low-level saturation and >13 V high-level output at 20 mA, sufficient to charge/discharge typical 1000 pF MOSFET gates within 150 ns. For >2 nF gates or high-side configurations, an external driver is recommended.
How does the 47–50% duty cycle limitation affect design?
This limit arises from an internal toggle flip-flop that blanks every other clock cycle, preventing subharmonic oscillation in continuous conduction mode. It restricts peak power transfer in flyback designs but improves stability and simplifies EMI filtering compared to 100% duty cycle controllers.
Is E-UC2845BD1013TR pin-compatible with UC3845BD1?
Yes - both are SO8-packaged members of the UCx84xB family with identical pinout, electrical characteristics, and functional behavior. The "E-" prefix denotes Aetrix's branded reel packaging and traceable lot coding; no electrical or mechanical differences exist.
E-UC2845BD1013TR 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):
- 48%
- 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-UC2845BD1013TR FAQ
1.How can I place an order for E-UC2845BD1013TR through Aetrix?
Please submit a Request for Quotation (RFQ) for E-UC2845BD1013TR 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-UC2845BD1013TR reliable?
The price and inventory of E-UC2845BD1013TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for E-UC2845BD1013TR is usually 5 days.
3.What payment methods are accepted for E-UC2845BD1013TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for E-UC2845BD1013TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for E-UC2845BD1013TR?
E-UC2845BD1013TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your E-UC2845BD1013TR 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-UC2845BD1013TR?
For technical support, including E-UC2845BD1013TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your E-UC2845BD1013TR requirements.
6.How does Aetrix verify that E-UC2845BD1013TR is sourced from the original manufacturer or authorized distributors?
All E-UC2845BD1013TR 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-UC2845BD1013TR meets industry standards.
7.What is the process for return or replacement of E-UC2845BD1013TR?
All E-UC2845BD1013TR units undergo pre-shipment inspection (PSI). If there is an issue with E-UC2845BD1013TR, 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-UC2845BD1013TR part is unused and in its original packaging.
Return procedure for E-UC2845BD1013TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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