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Analog Devices Inc. LTC3866EFE#TRPBF
- Part No.:
- LTC3866EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 24-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3866EFE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,995
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Product details
Overview
LTC3866EFE#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 0.2 mΩ), delivers up to 95% efficiency at 30 A output, supports 4.5 V–38 V input and 0.6 V–3.5 V output, and features ±0.5% 0.6 V reference accuracy for precision regulation in high-current DC/DC converters used in telecom power systems.
For engineers reviewing the LTC3866EFE#TRPBF datasheet, LTC3866EFE#TRPBF pinout, LTC3866EFE#TRPBF application, or LTC3866EFE#TRPBF equivalent, key selection criteria include its differential remote sense amplifier, programmable 10–30 mV current limit threshold, DCR temperature compensation via ITEMP, adjustable 250–770 kHz switching frequency, and support for Burst Mode® operation at light load.
Technical Context
The LTC3866EFE#TRPBF implements a proprietary current-sense architecture that processes dual positive inputs (SNSD+, SNSA+) to improve signal-to-noise ratio by 14 dB-enabling stable control with ultra-low-DCR inductors. Its error amplifier regulates VFB against a precise 0.6 V reference, while the ITH pin sets peak inductor current via voltage-controlled current comparator trip point.
It integrates a high-speed differential amplifier (gain = 0.999–1.002 V/V, GBW = 3 MHz), programmable DCR temperature compensation (via ITEMP current source), and mode-select logic (Burst Mode®, pulse-skipping, or CCM) controlled by MODE/PLLIN. The internal 5.5 V INTVCC regulator can be bypassed using EXTVCC ≥ 4.7 V for higher efficiency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 38 V - supports wide bus voltages including 5 V, 12 V, 24 V, and 36 V battery/supply rails. |
| Output Voltage Range | 0.6 V to 3.5 V - set via resistive divider from DIFFOUT to VFB; enables core voltage regulation for CPUs/FPGAs. |
| Feedback Reference | 0.6 V ±0.5% - guarantees ≤±3 mV absolute error over –40°C to 125°C, critical for <1 V output stability. |
| Switching Frequency | 250 kHz to 770 kHz - programmable via FREQ pin current (9–11 µA); allows optimization of size vs. efficiency. |
| Current Sense Threshold | 10 mV to 30 mV in 5 mV steps - selected by ILIM voltage; enables accurate overcurrent protection with low-DCR inductors. |
| DCR Temp Compensation | 9–11 µA ITEMP current - drives NTC thermistor near inductor to maintain constant current limit across temperature. |
| Remote Sense Accuracy | Gain = 0.998–1.002 V/V, PSRR = 90 dB - ensures <0.2% gain error and immunity to supply noise in precision feedback paths. |
Pinout & Package
The LTC3866EFE#TRPBF is housed in a 24-lead plastic TSSOP (FE package) with exposed pad (Pin 25 = SGND), θJA = 33°C/W. PCB layout requires soldering the exposed pad to ground plane for thermal and signal integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (Pin 1) | Oscillator frequency programming input | 10 µA current source; resistor to GND sets fSW from 250–770 kHz - enables EMI tuning without external clock. |
| RUN (Pin 2) | Enable/disable control | 1.22 V turn-on threshold with 80 mV hysteresis; internal 1 µA pull-up - supports sequenced power-up and system-level shutdown. |
| TK/SS (Pin 3) | Soft-start/tracking ramp input | 1.25 µA internal charge current; linear 0–0.6 V ramp - provides controlled VOUT rise or tracks another rail's startup profile. |
| ITH (Pin 4) | Error amplifier output / current limit threshold | Voltage sets peak inductor current; also used for loop compensation - direct interface to Type II/III compensation networks. |
| VFB (Pin 5) | Feedback input | Receives scaled output voltage from DIFFOUT divider; regulated to 0.6 V - primary control node for output voltage accuracy. |
| DIFFOUT (Pin 6) | Differential amplifier output | Drives VFB through external resistor divider; referenced to SGND - enables Kelvin sensing of remote load point. |
| SNSD+ (Pin 9) | Primary DCR sense input | Connects to inductor DCR filter with time constant matching L/DCR - main path for high-SNR current sensing. |
| SNSA+ (Pin 11) | Secondary DCR sense input | Filter bandwidth = 5× SNSD+; improves SNR further - essential for stable operation below 0.5 mΩ DCR. |
| ILIM (Pin 12) | Current limit threshold select | DC voltage selects 10/15/20/25/30 mV sense threshold - configures foldback or hard current limit without changing layout. |
| PGOOD (Pin 23) | Power-good open-drain output | Asserts after 20 µs mask timer when VFB within ±10% of 0.6 V - signals system controller that output is valid and stable. |
Key Features
| Feature | Design Value |
|---|---|
| Sub-milliohm DCR sensing | Supports inductors as low as 0.2 mΩ via dual-path sensing (SNSD+/SNSA+), reducing conduction loss and improving efficiency at >20 A loads. |
| Programmable current limit | Five discrete thresholds (10–30 mV) set by ILIM voltage - enables precise overcurrent protection matched to specific inductor DCR and thermal design. |
| Differential remote sense amplifier | 0.998–1.002 V/V gain, 3 MHz GBW, 90 dB PSRR - rejects common-mode noise and maintains <0.2% output voltage error under noisy PCB conditions. |
| DCR temperature compensation | ITEMP pin sources 9–11 µA to NTC thermistor - dynamically adjusts current limit to track inductor DCR drift over –40°C to 125°C. |
| Multiphase-ready synchronization | MODE/PLLIN accepts external clock up to 1 MHz - enables interleaved operation with other LTC controllers to reduce input/output ripple. |
Applications
| Telecom Power Supply | Industrial CPU Core Regulator |
|---|---|
Use Scenario: 12 V input to 1.2 V/30 A output for baseband processor in 5G radio unit with strict thermal limits and high transient response requirements. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing gate drive timing, current sensing, and output voltage regulation with differential remote sensing. Use Value: Sub-milliohm DCR sensing enables use of low-profile, high-current inductors; ±0.5% reference ensures <6 mV output deviation across line/load/temperature. | Use Scenario: Point-of-load converter supplying FPGA core voltage in programmable logic controller with pre-biased startup and sequencing constraints. IC Role / Device Role / Timing Role: Current-mode controller executing soft-start via TK/SS ramp and tracking startup of auxiliary 3.3 V rail using external resistor divider. Use Value: Adjustable soft-start prevents inrush current; differential sensing eliminates IR drop error at load pins, maintaining tight regulation at 1.0 V ±10 mV. |
| Medical Imaging Power Module | Automotive ADAS Domain Controller |
Use Scenario: High-reliability 24 V to 1.8 V/25 A converter powering ASIC in MRI subsystem requiring low EMI and fault tolerance. IC Role / Device Role / Timing Role: Controller implementing Burst Mode® at light load and foldback current limiting during short-circuit events. Use Value: 95% peak efficiency reduces heatsink size; PGOOD output coordinates system reset; thermal shutdown protects against sustained overload. | Use Scenario: 12 V automotive battery input to 1.0 V/20 A supply for vision processor in camera ECU, operating across –40°C to 105°C ambient. IC Role / Device Role / Timing Role: Synchronous buck controller with DCR temperature compensation (ITEMP) and wide-input UVLO (3.4–4.1 V). Use Value: ITEMP-driven NTC compensation maintains consistent current limit over temperature; 4.5–38 V input range accommodates cold-crank and load-dump transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3866IUF#TRPBF | Same silicon, QFN-24 (4 mm × 4 mm) package with θJA = 47°C/W; rated for full –40°C to 125°C junction range. | Better thermal performance in space-constrained layouts; preferred for high-power density designs where board area is limited. | Select when PCB real estate is constrained and thermal resistance must be minimized despite higher cost per unit area. |
| MP2918GL-Z | Monolithic 30 V, 30 A buck converter (integrated MOSFETs); fixed 600 kHz fSW; no DCR temperature compensation or dual-sense inputs. | Lower BOM count but lacks sub-milliohm DCR capability and remote sensing; max output current derated above 85°C. | Choose for cost-sensitive, medium-efficiency applications where layout simplicity outweighs ultra-high efficiency and precision current limiting. |
Compared with LTC3866IUF#TRPBF, the LTC3866EFE#TRPBF offers identical electrical performance but uses a TSSOP package with lower thermal resistance (θJA = 33°C/W) and industry-standard lead pitch - simplifying rework and inspection. Versus MP2918GL-Z, it trades integration for superior DCR sensing fidelity, temperature-compensated current limiting, and flexible frequency programming.
Availability
LTC3866EFE#TRPBF is available at Aetrix Electronics and suitable for telecom power supplies, industrial CPU core regulators, medical imaging modules, and automotive ADAS domain controllers requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LTC3866EFE#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, communications, and industrial markets.
The LTC3866 belongs to Linear's high-efficiency synchronous controller product line, designed specifically for high-current, low-voltage DC/DC conversion where ultra-low-DCR inductor sensing, differential remote voltage monitoring, and robust thermal management are critical.
FAQ
What is the maximum supported inductor DCR value for stable operation of the LTC3866EFE#TRPBF?
The LTC3866EFE#TRPBF is optimized for very low-DCR inductors, supporting values as low as 0.2 mΩ with proper PCB layout. While no absolute maximum DCR is specified, operation above ~5 mΩ degrades current-sense SNR and may require disabling SNSA+ filtering. For reliable sub-milliohm sensing, the SNSD+ RC filter must match the L/DCR time constant, and SNSA+ bandwidth must be five times higher - both verified in the LTC3866EFE#TRPBF typical application circuits.
Does the LTC3866EFE#TRPBF support output voltage tracking, and how is it implemented?
Yes, the LTC3866EFE#TRPBF supports output voltage tracking via the TK/SS pin. When an external resistor divider connects another supply rail to TK/SS, the controller regulates VFB to match the TK/SS voltage instead of the internal 0.6 V reference - causing VOUT to rise and fall proportionally. This feature is confirmed in the LTC3866EFE#TRPBF datasheet Figure 9 (Tracking Up and Down) and Application Information section, enabling coordinated startup/shutdown with multiple rails.
How does the LTC3866EFE#TRPBF handle short-circuit conditions, and what protection mechanisms are active?
The LTC3866EFE#TRPBF implements foldback output current limiting and short-circuit soft recovery. When sensed current exceeds the ILIM-set threshold, the controller reduces duty cycle progressively (foldback), then enters hiccup mode after sustained fault. During recovery, gate drive is gradually restored to prevent voltage overshoot. These behaviors are documented in the LTC3866EFE#TRPBF datasheet Features list and Typical Performance Characteristics (Figure G07, G08), ensuring safe operation under output shorts without latch-up.
Can the LTC3866EFE#TRPBF operate with only the internal INTVCC regulator, or is EXTVCC required for full functionality?
The LTC3866EFE#TRPBF operates fully with only the internal INTVCC regulator - powered from VIN when EXTVCC is left open or <4.7 V. EXTVCC is optional: connecting ≥4.7 V to EXTVCC bypasses the internal LDO, improving efficiency by eliminating linear regulator dropout loss. No functionality is lost without EXTVCC; this is confirmed in the LTC3866EFE#TRPBF Electrical Characteristics table (EXTVCC Switchover Voltage = 4.5–4.7 V) and Operation section.
What is the purpose of the two positive current sense inputs (SNSD+ and SNSA+) on the LTC3866EFE#TRPBF?
SNSD+ and SNSA+ implement a dual-path DCR sensing architecture to enhance signal-to-noise ratio by 14 dB. SNSD+ carries the primary filtered DCR voltage (RC = L/DCR), while SNSA+ carries a higher-bandwidth version (RC = L/5·DCR) that corrects for phase shift - enabling stable control with inductors as low as 0.2 mΩ. This architecture is explicitly described in the LTC3866EFE#TRPBF datasheet "Sensing Signal of Very Low DCR" section and Functional Block Diagram.
LTC3866EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-TSSOP (0.173", 4.40mm Width) 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-TSSOP
LTC3866EFE#TRPBF FAQ
1.How can I place an order for LTC3866EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3866EFE#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 LTC3866EFE#TRPBF reliable?
The price and inventory of LTC3866EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3866EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3866EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3866EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3866EFE#TRPBF?
LTC3866EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3866EFE#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 LTC3866EFE#TRPBF?
For technical support, including LTC3866EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3866EFE#TRPBF requirements.
6.How does Aetrix verify that LTC3866EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3866EFE#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 LTC3866EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3866EFE#TRPBF?
All LTC3866EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3866EFE#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 LTC3866EFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3866EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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