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Analog Devices Inc. LTC3866EUF#TRPBF
- Part No.:
- LTC3866EUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3866EUF#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,997
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Product details
Overview
LTC3866EUF#TRPBF from Analog Devices is a single-phase current-mode synchronous step-down switching regulator controller driving all-N-channel MOSFETs. It enables sub-milliohm DCR sensing (down to 0.2mΩ), delivers up to 95% efficiency at 30A output, supports 4.5V–38V input and 0.6V–3.5V output, and features ±0.5% 0.6V reference accuracy for precision regulation in high-current server and telecom power supplies.
For engineers reviewing the LTC3866EUF#TRPBF datasheet, LTC3866EUF#TRPBF pinout, LTC3866EUF#TRPBF application, or LTC3866EUF#TRPBF equivalent, key selection criteria include its programmable 250kHz–770kHz switching frequency, differential remote sense amplifier with 0.998–1.002 V/V gain, DCR temperature compensation via ITEMP, selectable 10–30mV current limit threshold, and 24-lead 4mm × 4mm QFN package with exposed SGND pad.
Technical Context
The LTC3866EUF#TRPBF implements a proprietary current-sense architecture that combines dual positive inputs (SNSD+, SNSA+) to improve signal-to-noise ratio by 14dB-enabling stable operation with ultra-low-DCR inductors. Its error amplifier drives the ITH pin to control peak inductor current, while the differential amplifier (DIFFP/DIFFN → DIFFOUT) provides accurate remote voltage sensing referenced to SGND.
It integrates a 5.5V INTVCC linear regulator (with EXTVCC bypass support), programmable burst/pulse-skipping/continuous conduction modes via MODE/PLLIN, and robust protection including output overvoltage lockout (±10% VFB trip), thermal shutdown, and short-circuit soft recovery. The internal oscillator supports external synchronization and offers ±0.5% frequency stability over temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 38V - supports wide bus voltages including 5V, 12V, 24V, and 36V battery systems without external pre-regulation. |
| Output Voltage Range | 0.6V to 3.5V - set via resistive divider from DIFFOUT to VFB, enabling precise core voltage regulation for CPUs/FPGAs. |
| Feedback Reference | 0.6V ±0.5% - guarantees ≤±3mV absolute error across –40°C to 125°C, critical for <1V load point accuracy. |
| Switching Frequency | 250kHz to 770kHz - programmable via FREQ pin current (9–11µA); allows optimization of size vs. efficiency in high-density designs. |
| Current Sense Threshold | 10mV to 30mV in 5mV steps - selected via ILIM voltage, enabling accurate foldback current limiting with low-DCR (<0.32mΩ) inductors. |
| Differential Amplifier Gain | 0.998–1.002 V/V - ensures <0.2% gain error over full temp range, preserving remote sense accuracy under PCB trace resistance variation. |
| Package | 24-lead 4mm × 4mm QFN with exposed SGND pad - provides low θJA = 47°C/W and requires soldered thermal pad for reliable 125°C junction operation. |
Pinout & Package
Package: 24-lead (4mm × 4mm) plastic QFN with exposed SGND pad (Pin 25), rated for –40°C to 125°C operating junction temperature. Exposed pad must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ITH (Pin 1) | Error amplifier output / current threshold control | Sets peak inductor current via voltage; connects to RC compensation network for loop stability. |
| VFB (Pin 2) | Feedback input to error amplifier | Receives scaled output voltage from DIFFOUT divider; regulated to 0.6V reference for output accuracy. |
| DIFFOUT (Pin 3) | Differential amplifier output | Drives VFB through resistor divider; enables Kelvin sensing of output rail independent of PGND routing. |
| DIFFN (Pin 4) | Negative input of diffamp | Must connect near load ground to reject common-mode noise and PCB IR drop in high-current paths. |
| DIFFP (Pin 5) | Positive input of diffamp | Must connect near load output to enable true remote sensing of VOUT at point-of-load. |
| SNSD+ (Pin 6) | Main DCR sense positive input | Connects to inductor DCR filter (R1C1 matching L/DCR); primary current sensing path with optimized SNR. |
| SNS– (Pin 7) | Current comparator negative input | Connected to output node; forms differential pair with SNSD+/SNSA+ for accurate peak current detection. |
| SNSA+ (Pin 8) | Secondary DCR sense positive input | Connects to faster filter (R2C2 = R1C1/5); enhances noise rejection and enables 14dB SNR improvement. |
| ILIM (Pin 9) | Current limit threshold programming | DC voltage sets max sense threshold (10–30mV); floating or tied to INTVCC disables limit. |
| CLKOUT (Pin 10) | Internal clock output | 180° out-of-phase with SW node; used for synchronizing auxiliary converters or monitoring switching timing. |
| PGND (Pin 11) | Power ground return | Return path for VIN/INTVCC decoupling caps and bottom MOSFET source; must be low-inductance connection. |
| BG (Pin 12) | Bottom gate driver output | Drives bottom N-MOSFET gate between PGND and INTVCC/EXTVCC; 1.1Ω pull-down RDS(ON). |
| SW (Pin 13) | Switch node | Connection point for inductor, bottom MOSFET drain, and top MOSFET source; experiences full VIN-to-GND swing. |
| TG (Pin 14) | Top gate driver output | Floating driver referenced to SW; swings from INTVCC below SW to VIN + INTVCC; 2.6Ω pull-up RDS(ON). |
| BOOST (Pin 15) | Bootstrap supply for TG | Connects to (+) terminal of bootstrap capacitor; swings from ~INTVCC–0.7V to VIN+INTVCC for high-side drive. |
| INTVCC (Pin 16) | Internal 5.5V regulator output | Powers internal logic and drivers; requires 4.7µF low-ESR cap to PGND; bypassed by EXTVCC >4.7V. |
| VIN (Pin 17) | Main input supply | Primary power source for INTVCC regulator and high-voltage circuitry; decouple with 0.1–1µF ceramic cap to PGND. |
| EXTVCC (Pin 18) | External bias supply input | When >4.7V, disables INTVCC LDO and powers IC directly-improves efficiency in multi-rail systems. |
| ITEMP (Pin 19) | DCR temperature compensation input | Connect to NTC thermistor near inductor; enables automatic current limit adjustment over temperature. |
| PGOOD (Pin 20) | Open-drain power-good indicator | Pulls low when VFB deviates >±10% from 0.6V after 20µs mask timer; requires external pull-up. |
| MODE/PLLIN (Pin 21) | Mode selection / external sync input | Ground = CCM; INTVCC = pulse-skipping; float = Burst Mode®; AC signal = PLL sync to external clock. |
| RUN (Pin 23) | Enable/disable control | 1.22V threshold turn-on; 1.14V hysteresis shutdown; internal 1µA pull-up; supports sequencing with other rails. |
| TK/SS (Pin 24) | Soft-start / tracking input | 1.25µA internal current charges external cap for linear ramp; also accepts external voltage for supply tracking. |
| SGND (Pin 25) | Signal ground reference | Exposed pad; must be soldered to PCB ground plane; reference for DIFFAMP, EA, and compensation components. |
Key Features
| Feature | Design Value |
|---|---|
| Sub-milliohm DCR sensing | Enables use of 0.2mΩ–0.32mΩ inductors without added sense resistors-reducing conduction loss and board area in 30A+ applications. |
| Dual-path current sensing (SNSD+/SNSA+) | Provides 14dB SNR improvement over conventional single-path sensing-suppressing switching noise corruption in high-dI/dt environments. |
| Programmable DCR temperature compensation | Compensates inductor DCR drift using external NTC on ITEMP pin-maintaining precise current limit across –40°C to 125°C ambient. |
| High-speed differential remote sense amplifier | 0.998–1.002 V/V gain with 3MHz GBW and 2V/µs slew rate-preserves transient response and accuracy despite long PCB traces. |
| Three light-load operating modes | Selectable Burst Mode®, pulse-skipping, or continuous conduction-optimizes efficiency from 1mA to 30A without compromising regulation or noise. |
| Robust protection suite | Includes output overvoltage lockout (±10%), thermal shutdown, short-circuit soft recovery, and undervoltage lockout-reducing need for external supervision circuits. |
Applications
| Computer Systems | Telecom Systems |
|---|---|
Use Scenario: Core voltage regulation for high-performance CPUs and FPGAs in rack-mounted servers requiring 1.5V/30A with <±1% tolerance. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing top/bottom N-MOSFETs, DCR-based current sensing, and remote voltage feedback. Use Value: Achieves 95% efficiency at full load using 0.32mΩ DCR inductor-reducing heat sink requirements and improving system power density. | Use Scenario: Point-of-load (POL) converter powering 48V-to-12V intermediate bus systems in 5G base station RF modules. IC Role / Device Role / Timing Role: High-input-voltage synchronous controller supporting 36V–48V input with precise 12V output regulation and fast transient response. Use Value: Wide 4.5V–38V input range eliminates need for pre-regulator; differential sensing rejects noise from adjacent RF power amplifiers. |
| Industrial Instruments | DC Power Distribution Systems |
Use Scenario: Programmable logic controller (PLC) backplane supplying 3.3V/10A to multiple I/O modules with strict EMI limits. IC Role / Device Role / Timing Role: Current-mode controller with selectable Burst Mode® operation to maintain low standby power and meet CISPR-22 Class B emissions. Use Value: Programmable 250kHz–770kHz frequency avoids sensitive frequency bands; soft-recovery prevents output voltage overshoot during fault clearing. | Use Scenario: Redundant 24V DC distribution unit in data center infrastructure requiring high reliability and current-limit accuracy across temperature. IC Role / Device Role / Timing Role: Dual-path DCR sensing controller with ITEMP-based temperature compensation for consistent 30A current limit from –25°C to 70°C ambient. Use Value: Eliminates need for external current-sense resistors-reducing power loss, board space, and calibration complexity in parallel power paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2940AGQ-Z | Integrated MOSFETs (40V/15A), fixed 500kHz frequency, no DCR temperature compensation, smaller 3mm × 3mm QFN | Targeted at lower-current, cost-sensitive applications where board space is constrained but DCR drift compensation is not required | Select MP2940AGQ-Z only for ≤15A loads with fixed-frequency needs and no remote sensing; lacks ITEMP and dual-path SNR enhancement. |
| ISL81601FRZ-T7A | 60V input rating, integrated drivers, no differential remote sense amplifier, supports multiphase via CLKOUT sync, 0.6V ref ±1% | Designed for higher-input-voltage industrial motor drives and solar inverters where 38V max input is insufficient | Choose ISL81601FRZ-T7A for >38V inputs or multiphase expansion; sacrifices ±0.5% reference accuracy and Kelvin sensing capability. |
Compared with MP2940AGQ-Z and ISL81601FRZ-T7A, the LTC3866EUF#TRPBF uniquely delivers sub-milliohm DCR sensing with 14dB SNR improvement, ±0.5% reference accuracy, and programmable DCR temperature compensation-making it optimal for high-current, high-precision POL applications where efficiency, thermal stability, and noise immunity are critical.
Availability
LTC3866EUF#TRPBF is available at Aetrix Electronics and suitable for computer systems, telecom infrastructure, and industrial instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed performance across –40°C to 125°C.
Supply support for LTC3866EUF#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and power management markets.
The LTC3866 belongs to Analog Devices' Power by Linear™ synchronous controller product line, engineered specifically for high-efficiency, high-current DC/DC conversion with advanced current sensing and thermal compensation in space-constrained, thermally demanding environments.
FAQ
What is the minimum DCR value supported by the LTC3866EUF#TRPBF for accurate current sensing?
The LTC3866EUF#TRPBF supports inductor DCR values as low as 0.2mΩ with careful PCB layout. Its dual-path sensing architecture (SNSD+ and SNSA+) delivers 14dB improved signal-to-noise ratio, enabling stable operation and precise current limit setting even at sub-milliohm levels-critical for minimizing conduction losses in 30A+ applications.
How does the LTC3866EUF#TRPBF implement DCR temperature compensation?
The LTC3866EUF#TRPBF uses the ITEMP pin to accept current from an external NTC thermistor placed near the output inductor. This current adjusts the internal current sense threshold proportionally to DCR drift, maintaining accurate current limiting across –40°C to 125°C. Floating or tying ITEMP to INTVCC disables this function.
Can the LTC3866EUF#TRPBF operate without an external bootstrap diode?
No-the LTC3866EUF#TRPBF requires an external bootstrap diode connected between INTVCC and BOOST to recharge the floating bootstrap capacitor during the bottom-FET-on phase. Omitting it prevents proper top-gate drive and causes immediate failure; the datasheet specifies a Schottky diode with <0.4V forward drop and low capacitance.
What is the purpose of the DIFFP and DIFFN pins on the LTC3866EUF#TRPBF?
The DIFFP and DIFFN pins form the inputs of the integrated differential remote sense amplifier in the LTC3866EUF#TRPBF. DIFFP connects near the load output and DIFFN near the load ground, enabling Kelvin sensing that rejects PCB trace resistance and ensures accurate regulation at the point-of-load-especially vital for low-voltage, high-current rails.
Does the LTC3866EUF#TRPBF support external clock synchronization?
Yes-the MODE/PLLIN pin of the LTC3866EUF#TRPBF accepts an external clock signal to force continuous conduction mode and synchronize the internal oscillator. When driven with a clean square wave within the 250kHz–770kHz range, it eliminates beat frequencies and EMI in multi-converter systems without requiring additional PLL circuitry.
LTC3866EUF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 38V
- Frequency - Switching:
- 250kHz ~ 770kHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
LTC3866EUF#TRPBF FAQ
1.How can I place an order for LTC3866EUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3866EUF#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 LTC3866EUF#TRPBF reliable?
The price and inventory of LTC3866EUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3866EUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3866EUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3866EUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3866EUF#TRPBF?
LTC3866EUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3866EUF#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 LTC3866EUF#TRPBF?
For technical support, including LTC3866EUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3866EUF#TRPBF requirements.
6.How does Aetrix verify that LTC3866EUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3866EUF#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 LTC3866EUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3866EUF#TRPBF?
All LTC3866EUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3866EUF#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 LTC3866EUF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3866EUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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