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Analog Devices Inc. LT3837EFE#TRPBF
- Part No.:
- LT3837EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3837EFE#TRPBF.pdf
- Description:
- IC REG CTRLR FLYBACK 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:6,570
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Product details
Overview
LT3837EFE#TRPBF from Analog Devices (formerly Linear Technology) is an isolated no-opto synchronous flyback controller IC for medium-power DC-DC conversion. It regulates output voltage via primary-side sensing of transformer flyback voltage, supports 4.5V–20V input, delivers up to 60W, and operates at programmable 50kHz–250kHz switching frequency with forced continuous conduction mode. Used in isolated 3.3V/10A power supplies.
For engineers reviewing the LT3837EFE#TRPBF datasheet, LT3837EFE#TRPBF pinout, LT3837EFE#TRPBF application, or LT3837EFE#TRPBF equivalent, key selection criteria include its optocoupler-free regulation architecture, dual gate drive outputs (PG/SG), UVLO threshold of 1.24V, feedback reference of 1.237V, and thermally enhanced 16-pin TSSOP package with exposed GND pad.
Technical Context
The LT3837EFE#TRPBF implements current-mode control with a flyback-specific feedback amplifier that samples transformer winding voltage only during the flyback period. Its internal collapse detect comparator disables the amplifier when the sensed voltage drops below 80% of VFB, ensuring accurate timing-critical sampling.
It integrates dedicated timing control blocks-including programmable minimum on-time (tON), enable delay (ENDLY), and PG turn-on delay (PGDLY)-to reject leakage inductance spikes and synchronize secondary-side rectification. Load compensation via RCMP/CCMP pins actively corrects for I·R drops across RDS(ON) and ESR in the output path.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VFB Regulation Voltage | 1.237 V ±17 mV - sets precise output voltage via external resistor divider without trimming |
| Switching Frequency Range | 50 kHz to 250 kHz - user-programmable via OSC capacitor; supports external synchronization on SYNC pin |
| VCC Operating Range | 4.5 V to 20 V - powers controller directly from input rail or auxiliary supply; includes undervoltage lockout |
| UVLO Threshold | 1.240 V ±25 mV - enables reliable start-up at defined input voltage; hysteresis controlled by external divider impedance |
| Gate Drive Outputs | PG and SG - dual high-current drivers (7.4 V high, 50 mV low) for primary MOSFET and synchronous secondary MOSFET |
| SENSE+/- Threshold | 98 mV typical - peak primary current limit set by sense resistor; blanked during tON(MIN) to avoid noise |
| Thermal Rating | Junction temperature range –40°C to +125°C - validated for industrial and medical isolation applications |
| Package | 16-lead TSSOP with exposed thermal pad (Pin 17 = GND) - θJA = 40°C/W; requires PCB soldering for thermal performance |
Pinout & Package
The LT3837EFE#TRPBF is housed in a thermally enhanced 16-lead plastic TSSOP package (FE grade) with an exposed GND pad (Pin 17) that must be soldered to the PCB for electrical integrity and thermal dissipation. Package dimensions and footprint comply with JEDEC MO-153.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SG (1) | Synchronous gate drive output | Drives secondary-side MOSFET; high dv/dt tolerance; active during flyback phase |
| VCC (2) | Controller supply input | Requires ≥4.7 µF bypass capacitor; powers internal regulator and gate drivers |
| tON (3) | Minimum on-time programming | Resistor sets absolute minimum primary switch conduction time per cycle |
| ENDLY (4) | Enable delay programming | Resistor sets fixed delay before feedback amplifier activation post-MOSFET turn-off |
| SYNC (5) | External clock synchronization input | Positive-edge triggered; threshold ≈1.53 V; tie to GND if unused |
| SFST (6) | Soft-start ramp control | Capacitor-to-GND sets VC ramp rate; limits inrush current at startup |
| OSC (7) | Oscillator timing node | Capacitor-to-GND sets switching frequency: fOSC ≈ 100 kHz × 100 / COSC(pF) |
| FB (8) | Feedback amplifier input | Receives scaled flyback voltage; high-impedance node (200 nA bias); Thevenin resistance ~3 kΩ recommended |
| VC (9) | Control loop compensation node | Integrates feedback error current; voltage proportional to peak primary current; connects to compensation network |
| UVLO (10) | Input undervoltage lockout sense | Resistive divider from VIN sets start-up threshold; hysteresis adjustable via divider impedance |
| SENSE– (11) | Current sense return | Kelvin connection point for sense resistor low-side; referenced to GND |
| SENSE+ (12) | Current sense input | High-side sense node; 98 mV threshold at max VC; blanked during tON(MIN) |
| CCMP (13) | Load compensation filter capacitor | 0.1 µF ceramic capacitor filters averaged primary current signal for load compensation |
| RCMP (14) | Load compensation resistor | Adjusts compensation gain; open for basic operation; required for tight load regulation |
| PGDLY (15) | Primary gate turn-on delay | Resistor sets delay from SG turn-off to PG turn-on; prevents shoot-through |
| PG (16) | Primary gate drive output | Drives high-side primary MOSFET; fast rise/fall times (<20 ns with 1 nF load) |
| GND (17) | Signal and power ground | Exposed thermal pad; must be soldered to PCB ground plane for thermal and EMI performance |
Key Features
| Feature | Design Value |
|---|---|
| No-opto isolated regulation | Eliminates optocoupler and TL431, reducing BOM count and improving dynamic response and long-term reliability |
| Synchronous rectification support | Dual gate drives (PG/SG) enable high-efficiency secondary-side synchronous MOSFET control, increasing efficiency >3% vs diode rectification |
| Programmable minimum on-time | Ensures consistent flyback pulse sampling across load and line conditions, preventing regulation loss at light loads |
| Active load compensation | RCMP/CCMP circuitry cancels voltage drop errors from RDS(ON) and ESR, enabling <±1% load regulation over full output range |
| Forced continuous conduction mode | Improves cross-regulation in multi-output designs by maintaining coupling between windings during entire switching cycle |
| Integrated protection functions | Includes UVLO, overcurrent fault detection (230 mV SENSE threshold), thermal shutdown, and soft-start with programmable ramp |
Applications
| Medical Isolated Power Supply | Industrial Instrumentation Supply |
|---|---|
Use Scenario: 3.3V/10A isolated DC-DC converter powering patient-connected monitoring circuits in Class II medical devices. IC Role / Device Role / Timing Role: Primary-side controller regulating output via transformer feedback winding; manages PG/SG timing to ensure safe, low-noise synchronous rectification. Use Value: Meets IEC 60601 creepage/clearance requirements without optocoupler; achieves >88% efficiency at full load per typical data. | Use Scenario: 9V–18V input to 3.3V isolated supply for precision analog front-ends in industrial PLC modules. IC Role / Device Role / Timing Role: No-opto flyback controller implementing load-compensated regulation to maintain ±0.5% output accuracy across 0–10A load step. Use Value: Eliminates calibration drift from optocoupler aging; enables stable 16-bit ADC reference voltage under varying ambient temperature. |
| Isolated Telecom Interface Supply | Test Equipment Auxiliary Rail |
Use Scenario: Compact 12V input to 5V/3A isolated supply for RS-485 transceivers in telecom base station backplanes. IC Role / Device Role / Timing Role: Synchronous flyback controller operating at 150kHz with external sync to avoid EMI interference with data lines. Use Value: Reduces conducted emissions via precise timing control and eliminates optocoupler-induced jitter in data communication paths. | Use Scenario: Bench-top test equipment requiring stable, isolated ±12V rails for op-amp biasing and sensor excitation. IC Role / Device Role / Timing Role: Dual-output flyback controller using forced CCM to tightly regulate both positive and negative outputs from single transformer. Use Value: Achieves <±1.5% cross-regulation between rails without post-regulation LDOs, saving board space and thermal overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolated flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28911DR | Primary-side sensing with integrated high-voltage FET; fixed 70kHz frequency; no synchronous drive outputs | Targeted at lower-power (<10W), cost-sensitive AC/DC adapters; lacks PG/SG dual-drive capability | Choose UCC28911DR only for non-synchronous, sub-10W designs where integration outweighs flexibility |
| MAX17690ATP+ | Wide-input (4.5V–60V) flyback controller with integrated 600mA gate drivers; supports quasi-resonant mode | Designed for higher-input industrial systems; lacks no-opto flyback feedback architecture and load compensation | Choose MAX17690ATP+ for wide-VIN applications requiring QR operation, but not for optocoupler-free precision regulation |
Compared with UCC28911DR and MAX17690ATP+, the LT3837EFE#TRPBF uniquely combines no-opto regulation, dual synchronous gate drives, and active load compensation-making it the only option among the three capable of delivering <±1% load regulation in isolated 10W–60W synchronous flyback designs without optocouplers.
Availability
LT3837EFE#TRPBF is available at Aetrix Electronics and suitable for medical isolation, industrial instrumentation, and telecom interface power supplies requiring stable component supply, long lifecycle support, and guaranteed traceable sourcing.
Supply support for LT3837EFE#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT3837EFE#TRPBF belongs to ADI's isolated power controller product line, designed specifically for high-reliability, optocoupler-free flyback converters in medical, industrial, and test equipment where safety certification, efficiency, and long-term stability are critical.
FAQ
What is the function of the ENDLY pin on the LT3837EFE#TRPBF?
The ENDLY pin on the LT3837EFE#TRPBF programs a fixed enable delay time after primary MOSFET turn-off, allowing transformer leakage inductance spikes to settle before the feedback amplifier activates. This ensures accurate flyback voltage sampling. A resistor from ENDLY to GND sets the delay-e.g., 90kΩ yields ~265 ns per datasheet. Incorrect ENDLY timing causes regulation error or instability in the LT3837EFE#TRPBF.
Does the LT3837EFE#TRPBF require an optocoupler for isolated output regulation?
No, the LT3837EFE#TRPBF does not require an optocoupler. It achieves isolated output regulation by sensing the flyback voltage from a dedicated transformer feedback winding and comparing it to its internal 1.237V reference at the FB pin. This no-opto architecture improves dynamic response, reliability, and long-term stability compared to traditional optocoupler-based solutions-core to the LT3837EFE#TRPBF's design.
How is load regulation improved using the RCMP and CCMP pins on the LT3837EFE#TRPBF?
The RCMP and CCMP pins on the LT3837EFE#TRPBF implement active load compensation by injecting a correction current into the FB node proportional to average primary current. This counteracts voltage drops across secondary-side RDS(ON) and ESR, enabling <±1% load regulation. A 0.1µF capacitor on CCMP and a calculated resistor on RCMP (e.g., 15kΩ–100kΩ) are required-omitting them degrades regulation in the LT3837EFE#TRPBF.
What is the purpose of the tON pin on the LT3837EFE#TRPBF?
The tON pin on the LT3837EFE#TRPBF sets the minimum on-time for the primary-side MOSFET switch per switching cycle. This ensures a consistent flyback pulse is generated even at light loads, preventing regulation loss and start-up instability. A resistor from tON to GND (e.g., 10kΩ) programs this time-critical for reliable no-opto operation in the LT3837EFE#TRPBF.
Can the LT3837EFE#TRPBF drive both primary and secondary MOSFETs synchronously?
Yes, the LT3837EFE#TRPBF provides two dedicated gate drive outputs: PG (Pin 16) for the primary-side MOSFET and SG (Pin 1) for the secondary-side synchronous rectifier. Both deliver high peak current (>1A), fast edge rates (<20 ns), and logic-level compatible voltages-enabling efficient synchronous rectification without external drivers in the LT3837EFE#TRPBF.
LT3837EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Flyback
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 20V
- Frequency - Switching:
- 100kHz
- Duty Cycle (Max):
- 88%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, On Time Control
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT3837EFE#TRPBF FAQ
1.How can I place an order for LT3837EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3837EFE#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 LT3837EFE#TRPBF reliable?
The price and inventory of LT3837EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3837EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3837EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3837EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3837EFE#TRPBF?
LT3837EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3837EFE#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 LT3837EFE#TRPBF?
For technical support, including LT3837EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3837EFE#TRPBF requirements.
6.How does Aetrix verify that LT3837EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3837EFE#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 LT3837EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3837EFE#TRPBF?
All LT3837EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3837EFE#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 LT3837EFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3837EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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