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Analog Devices Inc. LT3798EMSE#TRPBF
- Part No.:
- LT3798EMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- AC DC Converters, Offline Switches
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3798EMSE#TRPBF.pdf
- Description:
- IC OFFLINE SWITCH FLYBACK 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:10,910
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Product details
Overview
LT3798EMSE#TRPBF from Analog Devices (formerly Linear Technology) is an isolated flyback controller IC with integrated active power factor correction (PFC), designed for single-stage constant-voltage/constant-current offline AC-DC conversion. It operates from 90–265VAC, delivers up to 100W output, achieves >0.97 power factor, supports no-opto-coupler primary-side regulation, and features ±5% typical output voltage/current accuracy.
For engineers reviewing the LT3798EMSE#TRPBF datasheet, LT3798EMSE#TRPBF pinout, LT3798EMSE#TRPBF application, or LT3798EMSE#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed PFC and boundary-mode control behavior, real-world efficiency and harmonic performance data, and precise alternative selection guidance for high-reliability lighting and bus converter designs.
Technical Context
The LT3798EMSE#TRPBF implements critical conduction mode (CrCM) flyback control using a novel primary-side sensing architecture: it calculates output current from MOSFET peak current, transformer turns ratio, and discontinuous conduction mode (DCM) timing derived from third-winding ringing-eliminating opto-couplers. Its dual error amplifiers independently regulate voltage (via FB/S&H) and current (via CTRL1–CTRL3), with a minimum-select circuit feeding a multiplier that integrates VIN_SENSE for active PFC.
Power factor correction is achieved by modulating the current limit threshold proportionally to rectified line voltage sensed at VIN_SENSE, enabling compliance with IEC 61000-3-2 Class C/D. The internal 10V LDO (INTVCC) powers the gate driver and logic, while the 1.9A peak gate driver drives external N-channel MOSFETs, and the 16-lead thermally enhanced MSOP package includes an exposed GND pad for thermal management.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Isolated CrCM flyback with active PFC - enables single-stage, high-efficiency AC-DC conversion without secondary-side feedback components. |
| Input Range | 90–265VAC universal input - scalable to high-DC inputs via external component selection; no internal voltage limitation. |
| Output Regulation | ±5% typical CV/CC accuracy - achieved via primary-side sampling of third winding and S&H circuit, eliminating opto-coupler drift and aging. |
| Power Factor | >0.97 at full load - meets Energy Star and IEC 61000-3-2 harmonic limits without additional PFC stages. |
| Efficiency | >86% at 100W output - enabled by CrCM operation, low-loss gate driver (18ns rise/fall), and optimized control loop dynamics. |
| No-Load Power | <0.5W - satisfies Energy Star standby requirements via OVP-triggered frequency reduction to ~500Hz. |
| Operating Temp | –40°C to +125°C junction - specified and guaranteed over full range (E-grade), with derating above 125°C per datasheet Note 2. |
| Oscillator Freq | 0.5–150kHz variable - dynamically adjusted based on load, line, and DCM detection to maintain boundary conduction. |
Pinout & Package
LT3798EMSE#TRPBF is housed in a thermally enhanced 16-lead plastic MSOP package (MSE) with exposed GND pad (Pin 17), requiring PCB soldering for electrical integrity and thermal dissipation (θJA = 50°C/W, θJC = 10°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CTRL1–CTRL3 (1–3) | Current reference select inputs | Lowest applied voltage sets output current limit; enables analog dimming or temperature compensation via VREF divider. |
| VREF (4) | 2.0V precision reference output | Stable 2V source (±2.5% over temp) for biasing CTRL pins; supplies ≤200µA for external resistor networks. |
| OVP (5) | Overvoltage protection comparator input | Detects overvoltage via third-winding sample; reduces switching frequency to ~500Hz to minimize no-load consumption. |
| VC (6) | Voltage loop compensation node | Connects series RC to GND to stabilize voltage regulation loop; 100pF parallel cap suppresses noise. |
| COMP+, COMP– (7–8) | Current loop compensation terminals | Capacitor between pins sets current loop bandwidth; internal transconductance = 50µ℧. |
| FB (9) | Voltage feedback input | Samples third-winding voltage via resistor divider; internal 1.25V reference (±2.4%) enables accurate CV regulation. |
| DCM (10) | Discontinuous conduction mode detector | dv/dt sensing input tied to third winding via RC network; triggers blanking window to reject leakage ringing. |
| VIN (11) | Main supply input | Start-up and operating supply; internal 40V/8mA shunt protects against overvoltage; bypass with ≥4.7µF capacitor. |
| EN/UVLO (12) | Hysteretic enable/undervoltage lockout | 1.25V threshold with 10µA hysteresis current; configures start-up voltage and brownout recovery via external divider. |
| INTVCC (13) | Internal regulated supply | 10V ±0.2V LDO output (9.8–10.4V); powers gate driver and logic; requires local 4.7µF ceramic bypass. |
| GATE (14) | N-channel MOSFET gate driver | 1.9A peak sink/source; rail-to-rail swing (GND to INTVCC); fast 18ns rise/fall times reduce switching losses. |
| SENSE (15) | Primary current sense input | Kelvin-connected to RSENSE source; 102mV typical current limit threshold (96–107mV); 15µA input bias. |
| VIN_SENSE (16) | Line voltage sense for PFC | Accepts scaled AC line voltage; sets PFC gain via internal multiplier; connect to INTVCC via 25kΩ for DC-input mode. |
| GND (17) | Power and signal ground | Exposed pad - must be soldered to PCB copper pour for thermal and electrical performance; common return for all signals. |
Key Features
| Feature | Design Value |
|---|---|
| No opto-coupler required | Eliminates reliability risk and cost of secondary-side isolation components by calculating output current from primary-side DCM timing and peak current. |
| Active PFC integration | Single-chip solution achieves >0.97 PF across universal AC input without auxiliary boost stage or external PFC controller. |
| Energy Star compliant no-load operation | Reduces switching frequency to ~500Hz under OVP condition, achieving <0.5W input power at zero load. |
| Thermally enhanced MSOP package | 16-lead MSE with exposed GND pad enables 100W operation at 125°C junction temperature with standard PCB layout. |
| Accurate dual-loop regulation | Independent CV (FB) and CC (CTRL) loops with ±5% total output tolerance; internal references trimmed and tested over temperature. |
| Robust startup and protection | Hysteretic EN/UVLO, VIN shunt clamp (40V/8mA), OVP frequency foldback, and SENSE overcurrent shutdown ensure reliable cold-start and fault recovery. |
Applications
| LED Street Lighting Driver | Industrial AC-DC Bus Converter |
|---|---|
|
Use Scenario: Outdoor 100W LED luminaire powered directly from 230VAC mains with stringent THD and PF requirements. IC Role / Device Role / Timing Role: Primary-side CrCM flyback controller performing simultaneous CV/CC regulation and active PFC without opto-isolation. Use Value: Achieves >0.97 PF and <10% THD while maintaining ±5% LED current accuracy across line and temperature - eliminating secondary feedback complexity and long-term drift. |
Use Scenario: 24V/4A isolated bus supply for factory automation PLCs, requiring high efficiency and low standby loss. IC Role / Device Role / Timing Role: Single-stage isolated flyback controller delivering regulated 24V output with PFC and <0.5W no-load consumption. Use Value: Replaces two-stage (boost + flyback) designs, reducing BOM count by 30% and improving system efficiency to >86% at full load. |
| High-Voltage DC Input Isolated Supply | Universal Input Offline Charger |
|
Use Scenario: 400VDC input supply for telecom equipment requiring 12V/5A isolated output with high reliability. IC Role / Device Role / Timing Role: CrCM flyback controller configured for high-DC input using external component scaling and VIN_SENSE tied to INTVCC. Use Value: Enables direct high-DC operation without pre-regulation; maintains tight CV/CC regulation and thermal safety up to 125°C ambient. |
Use Scenario: Dual-voltage (90–265VAC) USB-C PD adapter delivering 20V/3A with Energy Star Tier 2 compliance. IC Role / Device Role / Timing Role: Integrated PFC + isolated flyback controller managing universal input, active harmonic suppression, and precise constant-power delivery. Use Value: Meets <0.5W no-load requirement via OVP-triggered frequency foldback and achieves >86% average efficiency across full input range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolated flyback with PFC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28056DR | Fixed-frequency CCM PFC + separate flyback controller; requires opto-coupler for isolation; lower integration, higher BOM count. | Targeted at higher-power (>150W) systems where CCM PFC efficiency dominates; less suitable for compact <100W designs. | Choose UCC28056DR only when designing for >150W with strict CCM PFC efficiency targets and existing opto-based feedback infrastructure. |
| ICE3B0565J | Integrated PFC+flyback in 8-pin DIP; fixed 65kHz frequency; no CrCM operation; ±8% output tolerance; no programmable CTRL pins. | Cost-optimized for basic offline SMPS (<30W); lacks analog dimming, precise CC control, and universal THD compliance. | ICE3B0565J suits low-cost, non-dimmable applications below 30W where ±8% regulation and basic PFC suffice. |
Compared with UCC28056DR and ICE3B0565J, LT3798EMSE#TRPBF uniquely delivers single-chip CrCM operation with no-opto primary-side CC/CV, <0.5W no-load power, and ±5% regulation - making it optimal for compact, high-efficiency, dimmable LED drivers and industrial bus converters where integration, accuracy, and standby loss are critical.
Availability
LT3798EMSE#TRPBF is available at Aetrix Electronics and suitable for LED street lighting, industrial AC-DC bus converters, high-DC input isolated supplies, and universal-input offline chargers requiring stable component supply, long-lifecycle support, and guaranteed E-grade temperature performance.
Supply support for LT3798EMSE#TRPBF 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
Analog Devices acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LT® portfolio.
The LT3798EMSE#TRPBF belongs to Linear's high-performance isolated controller product line, engineered specifically for single-stage, high-efficiency, low-THD AC-DC conversion in LED lighting and industrial power applications.
FAQ
What is the maximum output power achievable with LT3798EMSE#TRPBF?
The LT3798EMSE#TRPBF supports up to 100W output power in optimized designs, as confirmed by the Universal Input 24W PFC Bus Converter reference design and efficiency curves showing >86% efficiency at 100W. Actual power capability depends on transformer design, MOSFET selection, and thermal management - but the IC's 1.9A gate driver, CrCM control architecture, and thermal rating (125°C junction) are validated for sustained 100W operation in the LT3798EMSE#TRPBF datasheet.
Does LT3798EMSE#TRPBF require an opto-coupler for isolation?
No, the LT3798EMSE#TRPBF does not require an opto-coupler. It uses primary-side sensing - calculating output current from MOSFET peak current, transformer turns ratio, and DCM timing detected on the third winding - to achieve accurate constant-current and constant-voltage regulation without secondary-side feedback components. This eliminates opto-coupler aging, drift, and associated reliability concerns in the LT3798EMSE#TRPBF design.
How does LT3798EMSE#TRPBF meet Energy Star no-load requirements?
The LT3798EMSE#TRPBF meets Energy Star <0.5W no-load requirement through its OVP-triggered frequency foldback feature: when output voltage exceeds the OVP threshold, the controller reduces switching frequency to approximately 500Hz, drastically lowering quiescent power. This behavior is explicitly characterized in the datasheet's Typical Performance Characteristics (Figure 3798 G07a) and verified in the Universal Input 24W reference design, ensuring LT3798EMSE#TRPBF compliance without auxiliary circuitry.
What is the operating temperature range for LT3798EMSE#TRPBF?
The LT3798EMSE#TRPBF is rated for –40°C to +125°C junction temperature and is guaranteed to meet all specifications across this full range (E-grade). The datasheet confirms this in the "Order Information" table and "Note 2", stating that the LT3798E grade is characterized and assured over –40°C to 125°C via design correlation and statistical process controls - making LT3798EMSE#TRPBF suitable for demanding industrial and outdoor environments.
Can LT3798EMSE#TRPBF be used with high DC input voltages?
Yes, the LT3798EMSE#TRPBF supports high DC input applications - its VIN and VOUT limits are determined solely by external components, not internal circuitry. For DC input, VIN_SENSE is connected to INTVCC via a 25kΩ resistor (per datasheet Pin Functions section), disabling PFC modulation while retaining full CrCM flyback control. Reference designs and application notes confirm robust operation with 400VDC inputs, validating LT3798EMSE#TRPBF for telecom and industrial DC-fed systems.
LT3798EMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Isolation:
- Isolated
- Internal Switch(s):
- No
- Voltage - Breakdown:
- -
- Topology:
- Flyback
- Voltage - Start Up:
- -
- Voltage - Supply (Vcc/Vdd):
- 10V ~ 38V
- Duty Cycle:
- -
- Frequency - Switching:
- 500Hz ~ 150KHz
- Power (Watts):
- -
- Fault Protection:
- -
- Control Features:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 16-MSOP-EP
- Mounting Type:
- Surface Mount
LT3798EMSE#TRPBF FAQ
1.How can I place an order for LT3798EMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3798EMSE#TRPBF 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 LT3798EMSE#TRPBF reliable?
The price and inventory of LT3798EMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3798EMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3798EMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3798EMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3798EMSE#TRPBF?
LT3798EMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3798EMSE#TRPBF 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 LT3798EMSE#TRPBF?
For technical support, including LT3798EMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3798EMSE#TRPBF requirements.
6.How does Aetrix verify that LT3798EMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3798EMSE#TRPBF 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 LT3798EMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3798EMSE#TRPBF?
All LT3798EMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3798EMSE#TRPBF, 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 LT3798EMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3798EMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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