My Inquiry
My Account
Analog Devices Inc. LTC3874IUFD#PBF
- Part No.:
- LTC3874IUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3874IUFD#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,406
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3874IUFD#PBF from Analog Devices is a dual-phase PolyPhase® synchronous step-down slave controller designed for high-current, multi-phase DC/DC converters. It operates with a master controller (e.g., LTC3884, LTC3875), supports 250kHz–1MHz switching, enables sub-milliohm DCR current sensing (down to 0.2mΩ), and delivers precise phase-to-phase current sharing in telecom and datacom power rails up to 120A.
For engineers reviewing the LTC3874IUFD#PBF datasheet, LTC3874IUFD#PBF pinout, LTC3874IUFD#PBF application, or LTC3874IUFD#PBF equivalent, key selection considerations include its role as a non-voltage-regulating current-mode slave, programmable CCM/DCM operation, PHASMD-controlled phase alignment, and compatibility only within defined master-slave topologies-not as a standalone controller.
Technical Context
The LTC3874IUFD#PBF implements a proprietary peak current mode control architecture where ITH voltage from the master sets per-channel peak inductor current; it does not regulate output voltage-only current-for accurate dynamic load sharing. Its signal-enhanced DCR sensing circuit provides 14dB SNR improvement, enabling stable operation with 0.32mΩ inductors at 120A.
It integrates dual N-channel gate drivers (TG/BG) with matched RDS(ON) (1.5Ω/1.1Ω BG low, 2.6Ω/2.4Ω TG high), programmable phase shift via PHASMD (0°–300° relative to SYNC), and PLL-synchronized operation across 250kHz–1MHz. Fault response is immediate via FAULT0/FAULT1 inputs tied to master controller indicators.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Dual-phase synchronous buck slave controller-requires companion master IC for voltage regulation and ITH generation. |
| Input Voltage Range | 4.5V to 38V-supports wide-range industrial and telecom input buses including 12V, 24V, and 48V intermediate rails. |
| Switching Frequency | 250kHz to 1MHz-set via FREQ pin (10µA sink) or synchronized to external clock on SYNC pin with PLL lock. |
| DCR Sensing Range | Down to 0.2mΩ-enabled by LOWDCR pin high; requires careful Kelvin layout to maintain accuracy under high di/dt. |
| Current Sharing Accuracy | Phase-to-phase matching maintained during transients-achieved via matched current sense paths and peak current mode control. |
| Operating Temperature | –40°C to +125°C junction-qualified for industrial and base station environments with full electrical specs guaranteed. |
| Package | 28-lead 4mm × 5mm QFN with exposed thermal pad-designed for high-power density and efficient PCB heat dissipation. |
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 |
|---|---|---|
| MODE0 / MODE1 (1, 8) | DCM/CCM selection input | Logic high = forced continuous conduction mode; floating or low = discontinuous mode-enables light-load efficiency optimization. |
| ISENSE0+/ISENSE1+ (2, 7) | Current sense comparator (+) input | Connects to DCR filter network; common-mode range 0V–3.5V when LOWDCR = INTVCC-critical for sub-milliohm sensing fidelity. |
| ISENSE0−/ISENSE1− (3, 6) | Current sense comparator (−) input | Connected directly to VOUT node-forms Kelvin sense pair with ISENSE+ for accurate DCR voltage drop measurement. |
| RUN0 / RUN1 (4, 5) | Channel enable input | Logic high >2.0V enables channel; internal pull-down ensures safe shutdown-must be driven synchronously with master RUN pin. |
| ITH0 / ITH1 (28, 9) | Current threshold control input | Accepts master-generated analog voltage (1.38V–2.40V) to set per-channel peak current-no local regulation or clamping. |
| FREQ (10) | Frequency programming node | 10µA precision current sink-resistor to GND sets nominal frequency before PLL sync; required even when using SYNC. |
| SYNC (12) | External clock input | Falling-edge triggered PLL reference-enables coherent multi-phase operation and reduces input capacitor RMS current stress. |
| PHASMD (13) | Phase offset control | Analog voltage (GND to INTVCC) selects 4 discrete phase relationships between SYNC and TG0/TG1 outputs-key for interleaving. |
| TG0 / TG1 (24, 14) | Top gate driver output | Floating high-side drivers with 2.6Ω/2.4Ω RDS(ON)-drive N-MOSFET gates referenced to SW node; require bootstrap capacitors. |
| BG0 / BG1 (21, 17) | Bottom gate driver output | Ground-referenced drivers with 1.5Ω/1.1Ω RDS(ON)-directly drive N-MOSFET sources; anti-shoot-through logic prevents cross-conduction. |
| FAULT0 / FAULT1 (26, 25) | Master fault indicator input | Pull-down or float disables corresponding channel-connects to master's fault pin for coordinated shutdown on overcurrent/overvoltage. |
| LOWDCR (27) | Sub-milliohm sensing enable | Internal 500kΩ pull-up to INTVCC-tie high to activate enhanced SNR path for ≤0.32mΩ DCR inductors; tie low for standard sensing. |
Key Features
| Feature | Design Value |
|---|---|
| Proprietary DCR sensing architecture | 14dB SNR improvement enables stable 0.2mΩ inductor use-reduces conduction loss and eliminates need for current-sense resistors. |
| Programmable phase alignment | Four discrete phase offsets (0°–300°) via PHASMD pin-allows optimal interleaving across up to 12 phases with multiple LTC3874s and masters. |
| Dual independent gate drivers | Matched TG/BG timing (30ns rise/fall, 30ns dead time) and RDS(ON)-ensures balanced switching and minimizes shoot-through risk in high-current designs. |
| Master-slave current sharing | ITH-driven peak current control with synchronized clocking-maintains ±3% phase current balance across load transients without external compensation. |
| Flexible operating modes | Per-channel CCM/DCM selection via MODE pins-supports high-efficiency light-load operation while preserving low-noise performance in audio-sensitive systems. |
Applications
| Telecom Base Station Power | Data Center VR13/VR14 CPU Core Rails |
|---|---|
Use Scenario: 48V–12V intermediate bus supplying 1.8V/120A core voltage to high-performance ASICs in macrocell BTS. IC Role / Device Role / Timing Role: Slave controller extending phase count of LTC3884 master to achieve 8-phase operation-handles half the total current while maintaining tight current balance. Use Value: Enables use of ultra-low-DCR inductors (0.32mΩ), reducing conduction loss by >1.2W per phase versus conventional 1mΩ parts at 60A/channel. |
Use Scenario: Multi-phase 1.0V/200A VR for server CPUs requiring <±3mV regulation and fast transient response. IC Role / Device Role / Timing Role: Dual LTC3874IUFD#PBF units paired with LTC3875 master-provide 12-phase interleaved topology with 30° phase shift for minimized input ripple. Use Value: Reduces input capacitor RMS current by 75% vs. single-phase, allowing smaller 12× ceramic array instead of bulky polymer + electrolytic combo. |
| Industrial PLC I/O Power Module | AI Accelerator Board Power |
Use Scenario: 24V input powering isolated 3.3V/20A auxiliary rail for fieldbus communication and sensor interfaces. IC Role / Device Role / Timing Role: LTC3874IUFD#PBF acts as 2-phase slave to LTC3877 master-provides redundant current paths and fault propagation via FAULT0/FAULT1. Use Value: Immediate master-initiated shutdown on overtemperature or short-circuit-prevents damage to downstream EtherCAT PHY and isolated RS-485 transceivers. |
Use Scenario: 12V–0.8V/150A supply for GPU-like AI inference accelerators with bursty 50A/µs load steps. IC Role / Device Role / Timing Role: Slave controller in 6-phase configuration-uses DCM mode at idle and seamless transition to CCM under load for lowest possible noise floor. Use Value: Achieves <15mV p-p output ripple at full load while suppressing EMI in adjacent high-speed SerDes lanes-verified per CISPR-32 Class B. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multi-phase slave controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL68224IRZ-T7A | Digitally controlled 4-phase slave with PMBus interface; no analog ITH input-requires digital master or sequencer. | Designed for fully digital VR13/VR14 systems with telemetry and margining; lacks analog compatibility with LTC38xx masters. | Select only if migrating to digital control architecture; not drop-in compatible with existing LTC3874-based designs. |
| MP2960GQ-P | 3-phase analog slave with integrated MOSFET drivers; fixed 600kHz freq-no FREQ pin or PHASMD programmability. | Targeted at cost-sensitive client VRMs; supports only basic interleaving (120°/180°), no sub-milliohm DCR sensing. | Use for simpler 3-phase systems where phase flexibility and ultra-low-DCR operation are not required. |
Compared with ISL68224IRZ-T7A and MP2960GQ-P, the LTC3874IUFD#PBF uniquely combines analog ITH-based current mirroring, programmable phase offset, and validated sub-milliohm DCR support-making it the only option for upgrading legacy LTC38xx-based high-current telecom/datacom supplies without redesigning control loops.
Availability
LTC3874IUFD#PBF is available at Aetrix Electronics and suitable for telecom base station power, data center CPU VRMs, industrial PLC power modules, and AI accelerator board power requiring stable component supply across extended temperature and long production lifecycles.
Supply support for LTC3874IUFD#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 LTC3874IUFD#PBF belongs to the PolyPhase® synchronous controller product line, engineered specifically for scalable, high-current DC/DC conversion in infrastructure-grade power systems where reliability, phase coherence, and thermal efficiency are critical.
FAQ
Can the LTC3874IUFD#PBF operate as a standalone DC/DC controller without a master IC?
No. The LTC3874IUFD#PBF is strictly a slave controller-it lacks voltage feedback, error amplifier, and PWM generator circuitry. It relies entirely on an external master (e.g., LTC3884, LTC3875) to provide ITH voltage for current setting, RUN signals for enablement, and SYNC for clocking. Attempting standalone use will result in no regulated output.
What is the minimum DCR value supported by the LTC3874IUFD#PBF in sub-milliohm mode?
The LTC3874IUFD#PBF supports DCR values as low as 0.2mΩ when LOWDCR is pulled high and PCB layout follows strict Kelvin routing guidelines-short, matched traces for ISENSE+ and ISENSE−, capacitor placement adjacent to pins, and avoidance of noisy ground returns. Performance below 0.32mΩ requires validation per application note DC2203.
How does the PHASMD pin affect phase relationship between the two channels of the LTC3874IUFD#PBF?
The PHASMD pin sets four discrete phase offsets relative to the SYNC falling edge: GND = CH0@180°/CH1@0°, 1/3•INTVCC = CH0@60°/CH1@300°, 2/3•INTVCC = CH0@120°/CH1@240°, INTVCC = CH0@90°/CH1@270°. This enables precise interleaving across multiple LTC3874IUFD#PBF devices in systems scaling beyond 4 phases.
Does the LTC3874IUFD#PBF provide overcurrent protection independently of the master controller?
No. The LTC3874IUFD#PBF has no autonomous overcurrent protection-it depends on the master controller to clamp the ITH voltage and assert FAULT signals. Its ILIM and LOWDCR pins only configure current sense range and sensitivity; fault response is purely reactive via FAULT0/FAULT1 inputs.
What is the purpose of the EXTVCC pin on the LTC3874IUFD#PBF, and when should it be used?
The EXTVCC pin allows external 4.7V–6V bias to power the INTVCC regulator, bypassing the internal LDO when VIN >7V. This reduces power loss and thermal stress in high-input-voltage applications (e.g., 48V telecom buses). It must not exceed 6V and is optional-operation is fully functional with EXTVCC unconnected.
LTC3874IUFD#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)
LTC3874IUFD#PBF FAQ
1.How can I place an order for LTC3874IUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3874IUFD#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 LTC3874IUFD#PBF reliable?
The price and inventory of LTC3874IUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3874IUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3874IUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3874IUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3874IUFD#PBF?
LTC3874IUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3874IUFD#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 LTC3874IUFD#PBF?
For technical support, including LTC3874IUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3874IUFD#PBF requirements.
6.How does Aetrix verify that LTC3874IUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3874IUFD#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 LTC3874IUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3874IUFD#PBF?
All LTC3874IUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3874IUFD#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 LTC3874IUFD#PBF part is unused and in its original packaging.
Return procedure for LTC3874IUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3874IUFD#PBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
