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Analog Devices Inc. LTC3874EUFD#PBF
- Part No.:
- LTC3874EUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3874EUFD#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:118
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Product details
Overview
LTC3874EUFD#PBF from Analog Devices is a dual-phase PolyPhase® synchronous step-down slave controller designed to extend phase count in high-current multiphase DC/DC converters when paired with compatible master controllers (e.g., LTC3884, LTC3866). It supports sub-milliohm DCR current sensing (down to 0.2mΩ), operates across 4.5V–38V input, and delivers precise phase-to-phase current sharing in telecom/datacom power rails up to 120A at 1.8V.
For engineers reviewing the LTC3874EUFD#PBF datasheet, LTC3874EUFD#PBF pinout, LTC3874EUFD#PBF application, or LTC3874EUFD#PBF equivalent, key selection criteria include its 250kHz–1MHz PLL-synchronizable frequency range, programmable CCM/DCM mode per channel, dual N-channel gate drivers with <30ns transition times, and support for sub-milliohm DCR sensing without external op-amps.
Technical Context
The LTC3874EUFD#PBF implements a proprietary peak current mode control architecture where each channel's ITH voltage-driven by the master controller-directly sets peak inductor current. Its signal-enhanced DCR sensing circuit provides 14dB SNR improvement, enabling stable operation with 0.32mΩ inductors while suppressing switching jitter.
It features independent RUN0/RUN1 enable inputs, MODE0/MODE1 for per-channel CCM/DCM selection, and PHASMD/SYNC pins for precise phase alignment (0°–360° in 30° increments) across up to 12 phases. Fault response is immediate via FAULT0/FAULT1 inputs tied to master controller fault indicators.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4.5V to 38V - supports wide-input industrial and telecom supplies without pre-regulation |
| Switching Frequency | 250kHz to 1MHz - programmable via FREQ pin (10µA sink) or PLL-locked to SYNC input |
| Current Sense Threshold | 14.5mV to 79mV - selectable via ILIM/LOWDCR pins for accurate scaling with 0.2mΩ–1.5mΩ DCR |
| Gate Driver RDS(ON) | TG: 1.5Ω/2.6Ω (low/high); BG: 1.1Ω/2.4Ω - enables fast switching with low conduction loss in high-current N-MOSFET stages |
| Phase Shift Resolution | 30° increments (0°, 60°, 90°, 120°, 180°, 240°, 270°, 300°) - set by PHASMD voltage (GND to INTVCC) |
| Operating Temp | −40°C to +125°C - qualified for industrial and base station environments with full parameter guarantee |
| Package | 28-lead 4mm × 5mm QFN with exposed GND pad - optimized for thermal dissipation in high-power density layouts |
Pinout & Package
28-lead (4mm × 5mm) plastic QFN package with exposed GND pad (Pin 29), requiring solder connection to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN0 / RUN1 (Pins 4, 5) | Channel enable inputs | Logic-high (>2V) enables corresponding channel; internal 500kΩ pull-down ensures safe shutdown at power-up |
| ISENSE0+/1+, ISENSE0−/1− (Pins 2,3,6,7) | Differential current sense inputs | Accept Kelvin-connected DCR voltage; common-mode range 0V–3.5V when LOWDCR = INTVCC |
| ITH0 / ITH1 (Pins 28, 9) | Master-driven current threshold inputs | Directly scale peak inductor current per channel; no internal clamping - relies on master controller for overcurrent protection |
| TG0/TG1, BG0/BG1 (Pins 24,14,21,17) | N-MOSFET gate drivers | Floating top-gate outputs (TG) swing from SW node + INTVCC; bottom-gate (BG) drives from GND to INTVCC |
| SYNC (Pin 12), PHASMD (Pin 13) | PLL synchronization & phase offset control | SYNC accepts external clock falling edge; PHASMD voltage selects relative phase between channels and SYNC reference |
| ILIM (Pin 11), LOWDCR (Pin 27) | Current limit range & DCR sensitivity select | ILIM sets high/low current range (4 combinations); LOWDCR = INTVCC enables sub-milliohm sensing mode |
Key Features
| Feature | Design Value |
|---|---|
| Sub-milliohm DCR sensing | Supports 0.2mΩ inductors with 14dB SNR enhancement - eliminates need for sense resistors and associated power loss |
| Per-channel CCM/DCM mode control | MODE0/MODE1 pins independently configure forced continuous or discontinuous conduction - optimizes light-load efficiency vs. output ripple trade-off |
| Programmable phase alignment | PHASMD pin selects eight discrete phase offsets (0°–330°) - enables precise interleaving across ≥12 phases for RMS current reduction |
| Integrated EXTVCC switchover | Automatically bypasses internal LDO when EXTVCC > 4.7V and VIN > 7V - reduces self-heating in high-efficiency systems |
| Master-slave fault coordination | FAULT0/FAULT1 inputs pull down TG/BG immediately on master fault assertion - ensures synchronized shutdown without added logic |
Applications
| Telecom Base Station Power | Data Center VR13 Server Rails |
|---|---|
|
Use Scenario: 12-phase 1.8V/120A supply for ASIC/FPGA core voltage in 5G macro base stations. IC Role / Device Role / Timing Role: Slave controller extending phase count beyond master's native capability; synchronizes switching edges via SYNC/PHASMD to minimize input capacitor RMS current. Use Value: Reduces input capacitor RMS current by 75% vs. single-phase design, enabling smaller, lower-cost bulk capacitance and improved thermal margin. |
Use Scenario: Multiphase buck converter for CPU VDD rail in cloud server motherboards with strict transient response requirements. IC Role / Device Role / Timing Role: Dual-channel current-sharing slave operating under LTC3884 master control; uses ITH0/ITH1 to match master-set current demand in real time. Use Value: Achieves ±3% phase-to-phase current matching under dynamic load steps, preventing thermal imbalance and ensuring reliable long-term operation. |
| High-Density Storage System PSU | Industrial Programmable Logic Controller (PLC) |
|
Use Scenario: Compact 48V-to-3.3V intermediate bus converter powering NVMe SSD arrays in enterprise storage enclosures. IC Role / Device Role / Timing Role: Sub-milliohm DCR sensing slave enabling use of low-DCR planar inductors; operates in CCM mode for low output ripple critical to signal integrity. Use Value: Eliminates 2–3W of sense resistor loss per phase, improving system efficiency from 92% to 94.5% at 60A load. |
Use Scenario: Ruggedized 24V-to-5V/3.3V power module for distributed I/O modules in factory automation systems. IC Role / Device Role / Timing Role: Slave controller with independent RUN0/RUN1 enables staggered startup sequencing; FAULT0/FAULT1 inputs link to master watchdog for fail-safe shutdown. Use Value: Meets IEC 61000-4-5 surge immunity requirements by avoiding external current sense amplifiers vulnerable to ESD-induced latch-up. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multiphase slave controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3875IUFD#PBF | Single-channel, integrated master/slave architecture; includes internal voltage loop compensation and PMBus interface | Self-contained solution for ≤6-phase designs; no companion master required | Select when full autonomy, digital monitoring, or reduced BOM count outweighs need for ultra-high phase count scalability |
| ISL68224IRAZ-T7A | Dual-channel digital multiphase controller with embedded PWM logic; supports up to 8 phases per IC via daisy-chain | Native digital control with telemetry, but requires firmware configuration and lacks analog ITH interface | Select when system-level telemetry, adaptive voltage positioning, or multi-rail coordination are required over analog simplicity |
Compared with LTC3874EUFD#PBF, LTC3875IUFD#PBF integrates master functionality but limits maximum phase count, while ISL68224IRAZ-T7A offers digital flexibility at the cost of analog interoperability and added design complexity.
Availability
LTC3874EUFD#PBF is available at Aetrix Electronics and suitable for telecom base station power, data center VR13 server rails, and industrial PLC power systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3874EUFD#PBF 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 LTC3874EUFD#PBF belongs to the PolyPhase® multiphase controller family, engineered specifically for scalable, high-current DC/DC conversion in infrastructure-grade power systems where efficiency, thermal density, and phase synchronization are critical.
FAQ
What is the primary function of the LTC3874EUFD#PBF in a multiphase power system?
The LTC3874EUFD#PBF functions exclusively as a synchronous step-down slave controller. It does not regulate output voltage directly; instead, it precisely controls per-phase inductor current based on ITH voltage signals from a companion master controller (e.g., LTC3884). Its role is to extend phase count, ensure accurate current sharing, and maintain synchronized switching across all phases - enabling high-current, low-ripple power delivery in telecom and datacenter applications.
Can the LTC3874EUFD#PBF operate as a standalone controller without a master IC?
No, the LTC3874EUFD#PBF cannot operate as a standalone controller. It lacks voltage feedback circuitry, error amplifier, and output voltage regulation capability. All output voltage control, soft-start, and overvoltage/undervoltage protection must be handled by a compatible master controller (e.g., LTC3884, LTC3866). The LTC3874EUFD#PBF relies entirely on ITH0/ITH1 inputs for current command and SYNC for timing - making master-slave pairing mandatory.
How does the LOWDCR pin affect current sensing performance in the LTC3874EUFD#PBF?
The LOWDCR pin (Pin 27) enables or disables the LTC3874EUFD#PBF's proprietary sub-milliohm DCR sensing architecture. When pulled high (to INTVCC or left floating), it activates enhanced signal processing that improves SNR by 14dB - allowing stable operation with inductors as low as 0.2mΩ DCR. When pulled low, the device reverts to standard DCR sensing with higher minimum DCR tolerance (~1.5mΩ), sacrificing efficiency and noise immunity for compatibility with legacy designs.
What are the absolute maximum ratings for the TG0 and BG0 driver outputs on the LTC3874EUFD#PBF?
The absolute maximum ratings for TG0 (Pin 24) and BG0 (Pin 21) are defined relative to their respective reference nodes: TG0 withstands −5V to 40V versus SW0, while BG0 withstands −0.3V to 6V versus GND. Critically, the voltage difference between BOOST0 and SW0 must remain within −0.3V to +6V. These limits ensure safe operation during bootstrapping and prevent gate driver latch-up or oxide breakdown in external N-MOSFETs driven by the LTC3874EUFD#PBF.
Does the LTC3874EUFD#PBF support both continuous and discontinuous conduction modes, and how is mode selected?
Yes, the LTC3874EUFD#PBF supports both forced continuous conduction mode (CCM) and discontinuous conduction mode (DCM) on a per-channel basis. Mode selection is controlled by the MODE0 (Pin 1) and MODE1 (Pin 8) inputs: tying either pin above 2V (e.g., to INTVCC) forces CCM; pulling below 1.4V (e.g., to GND) or leaving floating (due to internal 500kΩ pull-down) defaults to DCM. This allows independent optimization of light-load efficiency (DCM) versus output ripple and audio noise (CCM) per channel.
LTC3874EUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 38V
- Frequency - Switching:
- 250kHz ~ 1MHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Phase Control
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC3874EUFD#PBF FAQ
1.How can I place an order for LTC3874EUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3874EUFD#PBF 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 LTC3874EUFD#PBF reliable?
The price and inventory of LTC3874EUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3874EUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3874EUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3874EUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3874EUFD#PBF?
LTC3874EUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3874EUFD#PBF 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 LTC3874EUFD#PBF?
For technical support, including LTC3874EUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3874EUFD#PBF requirements.
6.How does Aetrix verify that LTC3874EUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3874EUFD#PBF 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 LTC3874EUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3874EUFD#PBF?
All LTC3874EUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3874EUFD#PBF, 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 LTC3874EUFD#PBF part is unused and in its original packaging.
Return procedure for LTC3874EUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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