My Inquiry
My Account
Analog Devices Inc. LTC3856EUH#TRPBF
- Part No.:
- LTC3856EUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3856EUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,934
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3856EUH#TRPBF from Analog Devices (formerly Linear Technology) is a dual-channel, polyphase synchronous step-down DC/DC controller driving all-N-channel MOSFETs. It features a high-speed differential amplifier for true remote voltage sensing, DCR or RSENSE current sensing with programmable temperature compensation, and phase-lockable fixed-frequency operation up to 770 kHz. Designed for high-current 1.5V/50A telecom power supplies, it supports Burst Mode, Stage Shedding, and Active Voltage Positioning.
For engineers reviewing the LTC3856EUH#TRPBF datasheet, LTC3856EUH#TRPBF pinout, LTC3856EUH#TRPBF application, or LTC3856EUH#TRPBF equivalent, key selection criteria include its 4.5V–38V input range, ±0.75% reference accuracy at 0.6V, dual-phase interleaving for reduced ripple, differential remote sense capability, and 32-pin 5mm × 5mm QFN package with exposed thermal pad.
Technical Context
The LTC3856EUH#TRPBF implements a constant-frequency current-mode control architecture with independent per-phase current sensing via SENSE1+/– and SENSE2+/– inputs. Its error amplifier output (ITH) directly sets peak inductor current, while VFB receives regulated feedback either through resistive dividers or via DIFFOUT from the integrated differential amplifier (gain = 0.998–1.002 V/V).
Phase synchronization is achieved via PLLIN or CLKOUT chaining; PHASMD selects 60°, 90°, or 120° clock offset for multi-IC stacking up to 12 phases. The controller supports three light-load modes-Burst Mode (MODE = float), Stage Shedding (MODE = INTVCC), and forced continuous conduction (MODE = SGND)-with programmable thresholds via ISET and ILIM pins.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 38V - supports wide-range intermediate bus and battery-powered systems without external pre-regulation |
| Output Voltage Range | 0.6V to 5.0V without diffamp; 0.6V to 3.3V with diffamp - enables precise core voltage regulation for CPUs/FPGAs |
| Reference Accuracy | ±0.75% at 0.6V - ensures tight output regulation across temperature and line/load variations |
| Switching Frequency | 250kHz to 770kHz, phase-lockable - allows EMI optimization and predictable thermal design |
| Current Sensing | RSENSE or DCR with programmable tempco - maintains accurate current limit over –40°C to 125°C junction range |
| Max Output Current | Supports ≥50A per channel in 2-phase configuration - enables high-density, low-noise power delivery |
| Package | 32-pin 5mm × 5mm QFN with exposed SGND/PGND pad - provides low thermal resistance (θJA = 34°C/W) |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed thermal pad (Pin 33 = SGND/PGND, must be soldered to PCB).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| TK/SS (Pin 1) | Soft-start / tracking input | Internal 1.25µA current charges external capacitor to ramp VOUT linearly; enables supply sequencing |
| VFB (Pin 2) | Error amplifier feedback input | Compares sensed output to 0.6V reference; accepts signal from DIFFOUT or external divider |
| ITH (Pin 3) | Error amp output / current threshold | Directly controls per-phase peak inductor current; used for loop compensation |
| AVP (Pin 4) | Active Voltage Positioning slope | Resistor to DIFFP sets load-line droop for CPU VRM compliance; requires diffamp use |
| ITEMP (Pin 5) | Temperature sensing input | Connects to NTC thermistor near hot components to scale current limit vs. temperature |
| PHASMD (Pin 6) | CLKOUT phase select | GND/INTVCC/floating configures 60°/120°/90° clock offset for multi-phase synchronization |
| DIFFP (Pin 9) | Differential amp + input | Must connect directly to remote load point; enables millivolt-level sensing accuracy |
| DIFFN (Pin 10) | Differential amp – input | Connects to negative terminal of output capacitors; rejects common-mode noise |
| DIFFOUT (Pin 11) | Differential amp output | Drives VFB through resistor divider; eliminates IR drop errors in high-current rails |
| ISET (Pin 12) | Stage shedding / burst threshold | Resistor-to-ground programs current threshold for mode transitions and current limiting |
| ILIM (Pin 13) | Current sense range select | GND/float/INTVCC selects max sense voltage (25/50/75 mV) for full-scale current detection |
| MODE (Pin 14) | Light-load mode control | GND = forced continuous; INTVCC = stage shedding; floating = Burst Mode |
| PGOOD (Pin 15) | Power-good open-drain output | Pulls low when VOUT deviates >±10% after 20µs mask timer; signals system readiness |
| SW1, SW2 (Pins 16, 26) | Switch node connections | Connect to inductor ends; swing from ~–0.3V to VIN; require low-inductance layout |
| TG1, TG2 (Pins 17, 25) | Top gate drivers | Drive high-side N-MOSFET gates with 2.6Ω pull-up / 1.5Ω pull-down; bootstrap powered |
| BOOST1, BOOST2 (Pins 18, 24) | Bootstrap supply inputs | Accept floating voltage up to VIN + INTVCC; charge external bootstrap capacitors |
| BG1, BG2 (Pins 19, 23) | Bottom gate drivers | Drive low-side N-MOSFET gates with 2.4Ω pull-up / 1.1Ω pull-down; referenced to PGND |
| VIN (Pin 22) | Main input supply | 4.5V–38V input; decoupled with 0.1µF ceramic; powers internal LDO and logic |
| INTVCC (Pin 21) | Internal 5V regulator output | Supplies gate drivers and analog circuitry; requires ≥4.7µF low-ESR capacitor to PGND |
| EXTVCC (Pin 20) | External bias input | Bypasses internal LDO when >4.7V applied; improves efficiency in multi-rail systems |
| PLLIN (Pin 28) | External sync input | Accepts external clock to synchronize switching frequency across multiple controllers |
| CLKOUT (Pin 27) | Synchronized clock output | Provides phase-adjustable clock for daisy-chaining additional LTC3856 ICs |
| SENSE1+, SENSE1– (Pins 31, 32) SENSE2+, SENSE2– (Pins 7, 8) | Per-phase current sense inputs | Accept DCR network or sense resistor signals; support bidirectional sensing with reverse-current protection |
| RUN (Pin 30) | Enable control input | 1.22V threshold with 80mV hysteresis; internal 1µA pull-up; enables/disables full controller operation |
| FREQ (Pin 29) | Oscillator frequency set | Resistor-to-ground or DC voltage sets fSW from 250kHz to 770kHz; enables EMI tuning |
Key Features
| Feature | Design Value |
|---|---|
| PolyPhase® dual-channel interleaving | Reduces input/output ripple current by up to 50% versus single-phase, enabling smaller bulk capacitors and lower EMI |
| True remote differential sensing | 0.998–1.002 gain and 100dB PSRR eliminate IR drop errors in high-current PCB traces |
| Programmable DCR temperature compensation | Maintains ±1% current sense accuracy over –40°C to 125°C using external NTC on ITEMP pin |
| Stackable up to 12-phase operation | CLKOUT/PLLIN interface and PHASMD pin enable deterministic phase alignment across multiple ICs |
| Active Voltage Positioning (AVP) | Programmable load-line droop via AVP–DIFFP resistor satisfies Intel VRM specifications for CPU core rails |
| Three selectable light-load modes | Burst Mode (high efficiency <1A), Stage Shedding (adaptive phase reduction), or forced continuous (low noise) |
Applications
| Telecom Power Systems | Data Center Voltage Regulators |
|---|---|
Use Scenario: 12V intermediate bus conversion to 1.5V/50A for baseband processing units in 5G macrocells. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing parallel MOSFET stages with interleaved timing to minimize input ripple. Use Value: Achieves >95% efficiency at full load and <15mV output deviation under 50A transient steps via remote sensing and AVP. | Use Scenario: High-density server motherboard VRM delivering 0.8V/120A to dual-socket Xeon processors. IC Role / Device Role / Timing Role: Master controller in stacked 6-phase configuration, synchronized via PLLIN/CLKOUT to suppress beat frequencies. Use Value: Enables sub-10mV load-line regulation and <50µs transient response using DCR sensing and differential feedback. |
| Industrial Motor Drives | Medical Imaging Power Supplies |
Use Scenario: Isolated auxiliary supply generating 3.3V/20A for FPGA-based motion control logic in servo drives. IC Role / Device Role / Timing Role: Primary DC/DC controller regulating isolated secondary-side output with precise remote sensing across isolation barrier. Use Value: Maintains ±0.5% output accuracy despite 150mΩ trace resistance between converter and FPGA power pins. | Use Scenario: Low-noise 1.2V/30A supply for ADC/DAC subsystems in MRI gradient amplifiers. IC Role / Device Role / Timing Role: Dual-phase controller operating in forced continuous mode to eliminate switching frequency sidebands in analog signal chain. Use Value: Delivers <10µVpp output noise and <20ns propagation delay matching between phases for coherent sampling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2940AGQ-DC | Integrated MOSFETs (40V/40A); no external gate drivers; fixed 600kHz fSW; no differential amplifier | Lower BOM count for ≤40A designs; lacks remote sense and AVP for CPU VRMs | Select when board space is constrained and output current ≤40A; avoid for precision remote sensing or VRM compliance |
| ISL95852IRZ | Intel VR12.5-compliant; integrated telemetry; SMBus interface; 3.3V–24V input; no DCR tempco | Designed for laptop CPU VRMs with dynamic VID; includes digital monitoring not present in LTC3856EUH#TRPBF | Select for portable computing platforms requiring SVID communication; not suitable for industrial 38V bus systems |
Compared with MP2940AGQ-DC and ISL95852IRZ, the LTC3856EUH#TRPBF offers superior flexibility in input range (up to 38V), precision remote sensing, and analog programmability-making it optimal for high-reliability telecom and industrial power systems where discrete MOSFET selection and thermal management are critical.
Availability
LTC3856EUH#TRPBF is available at Aetrix Electronics and suitable for telecom infrastructure, data center VRMs, industrial motor drives, and medical imaging power supplies requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC3856EUH#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 and maintains its high-performance power management portfolio with rigorous automotive-grade qualification and military-spec process controls.
The LTC3856EUH#TRPBF belongs to Linear's PolyPhase® controller family, engineered specifically for high-current, low-voltage DC/DC conversion in infrastructure equipment where efficiency, thermal performance, and multi-phase synchronization are mission-critical.
FAQ
What is the maximum supported switching frequency for the LTC3856EUH#TRPBF?
The LTC3856EUH#TRPBF supports a phase-lockable fixed-frequency range from 250 kHz to 770 kHz. At VFREQ = 2.4V or higher, the nominal frequency reaches 770 kHz (typical), enabling compact magnetics and optimized EMI filtering. Frequency is set via a resistor to ground on the FREQ pin or by applying a DC voltage, and remains stable across temperature and input voltage variations per the datasheet's oscillator characterization.
Does the LTC3856EUH#TRPBF support both DCR and RSENSE current sensing?
Yes, the LTC3856EUH#TRPBF supports both DCR and RSENSE current sensing on each channel via dedicated SENSE1+/– and SENSE2+/– pins. When using DCR sensing, the ITEMP pin enables programmable NTC-based temperature compensation to maintain accuracy over –40°C to 125°C. For RSENSE, the ILIM pin selects one of three full-scale thresholds (25/50/75 mV) to match sense resistor values and current ranges.
How does the differential amplifier in the LTC3856EUH#TRPBF improve regulation accuracy?
The LTC3856EUH#TRPBF's integrated differential amplifier (DIFFP/DIFFN/DIFFOUT) provides true Kelvin sensing by rejecting common-mode noise and eliminating PCB trace IR drop errors. With 0.998–1.002 V/V gain and 100 dB PSRR, it delivers millivolt-level accuracy at the load point-even with 100+ mΩ interconnect resistance-ensuring ±0.75% output regulation is maintained under dynamic load transients and thermal drift.
Can the LTC3856EUH#TRPBF be used in a single-phase configuration?
Yes, the LTC3856EUH#TRPBF can operate in single-phase mode by connecting both TG1/TG2 and BG1/BG2 outputs in parallel and tying SENSE1+/– and SENSE2+/– together. However, its full value is realized in dual-phase interleaved operation, where ripple cancellation, thermal spreading, and current sharing improve efficiency and reliability. Single-phase use forfeits PolyPhase® benefits but retains all control features including AVP and remote sensing.
What thermal considerations apply to the LTC3856EUH#TRPBF's QFN package?
The LTC3856EUH#TRPBF uses a 32-pin 5mm × 5mm QFN with an exposed SGND/PGND pad (Pin 33) that must be soldered to a thermal land on the PCB. Its thermal resistance is θJA = 34°C/W. To maintain TJ ≤ 125°C, ensure ≥200 mm² copper area under the pad with ≥4 thermal vias to inner ground planes. Avoid routing high-current traces beneath the IC to prevent localized heating that degrades current-sense accuracy.
LTC3856EUH#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 32-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:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 38V
- Frequency - Switching:
- 250kHz ~ 770kHz
- Duty Cycle (Max):
- 94%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Phase Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC3856EUH#TRPBF FAQ
1.How can I place an order for LTC3856EUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3856EUH#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 LTC3856EUH#TRPBF reliable?
The price and inventory of LTC3856EUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3856EUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3856EUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3856EUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3856EUH#TRPBF?
LTC3856EUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3856EUH#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 LTC3856EUH#TRPBF?
For technical support, including LTC3856EUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3856EUH#TRPBF requirements.
6.How does Aetrix verify that LTC3856EUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3856EUH#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 LTC3856EUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3856EUH#TRPBF?
All LTC3856EUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3856EUH#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 LTC3856EUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC3856EUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3856EUH#TRPBF 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…
