My Inquiry
My Account
Analog Devices Inc. LTC3850EUFD#PBF
- Part No.:
- LTC3850EUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3850EUFD#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:136
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3850EUFD#PBF from Analog Devices is a dual, 2-phase synchronous step-down switching controller driving all-N-channel MOSFET stages. It delivers up to 95% efficiency, supports 250kHz–780kHz phase-lockable fixed-frequency operation, and features ±1% 0.8V reference accuracy. Used in high-density DC power distribution systems requiring tightly regulated dual outputs.
For engineers reviewing the LTC3850EUFD#PBF datasheet, LTC3850EUFD#PBF pinout, LTC3850EUFD#PBF application, or LTC3850EUFD#PBF equivalent, key selection criteria include dual-phase interleaving for input capacitance reduction, RSENSE/DCR current sensing flexibility, OPTI-LOOP® compensation for transient optimization, and independent soft-start/tracking via TK/SS pins.
Technical Context
The LTC3850EUFD#PBF implements constant-frequency current-mode control with two 180° out-of-phase channels, minimizing input ripple and supply-induced noise. Each channel uses an error amplifier (EA) with transconductance of 2.2 mmho and a precision 0.8V reference with ±1% accuracy over temperature.
It supports three light-load operating modes-Burst Mode®, pulse-skipping, and forced continuous conduction-selected via the MODE/PLLIN pin. The IC integrates dual N-channel gate drivers (TG/BG), internal 5V INTVCC regulator (4.8–5.2V), and programmable current foldback via ILIM pin configuration (20/40/60 mV thresholds).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Dual synchronous buck controller with 180° interleaved phases - reduces input capacitor RMS current by ~30% vs single-phase. |
| Switching Frequency | 250kHz to 780kHz, phase-lockable - enables EMI reduction via external clock sync or frequency tuning via FREQ/PLLFLTR voltage. |
| Reference Voltage | 0.8V ±1% - ensures tight output regulation across load/temperature for 3.3V/2.5V/1.8V rails. |
| Input Voltage Range | 4V to 24V (30V max for automotive-grade variants) - supports wide battery chemistries and intermediate bus voltages. |
| Current Sensing | RSENSE or DCR-based - allows flexible layout with low-loss inductor sensing or precise shunt-based measurement. |
| Efficiency | Up to 95% at full load - achieved via low-RDS(on) gate drive (TG RUP = 2.6Ω, BG RDOWN = 1.1Ω) and optimized dead-time control. |
| Soft-Start | Programmable via 1.3µA TK/SS charge current - enables controlled ramp-up of dual outputs with independent tracking capability. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN (UFD), exposed pad (Pin 29) soldered to PCB as SGND/PGND thermal and electrical connection. θJA = 34°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2 (Pins 27, 10) | Channel enable/disable control | Independent shutdown: >1.22V enables; <1.1V disables. Internal 0.5µA pull-up + 4.5µA active pull-up ensures reliable start-up sequencing. |
| TK/SS1, TK/SS2 (Pins 2, 7) | Soft-start and output tracking input | 1.3µA internal current charges external capacitor for linear VOUT ramp; also accepts resistor-divided master rail for synchronized startup. |
| SENSE1+/–, SENSE2+/– (Pins 28, 1, 9, 8) | Current sense comparator inputs | Differential inputs for RSENSE or DCR networks; bias current ±1µA minimizes sensing error at low currents. |
| VFB1, VFB2 (Pins 4, 5) | Error amplifier feedback input | Connects to resistive divider from output; regulates to 0.8V reference with ±1% accuracy and ±50nA input leakage. |
| MODE/PLLIN (Pin 25) | Operating mode select & PLL sync input | Ground = forced CCM; INTVCC = pulse-skipping; floating = Burst Mode®; external clock = synchronization source. |
| PGOOD (Pin 13) | Open-drain power-good indicator | Asserts low when either VOUT deviates >±7.5% from target after 17µs mask timer - enables system-level power sequencing. |
| TG1/TG2, BG1/BG2 (Pins 23, 15, 21, 18) | N-channel MOSFET gate drivers | TG drives top FET with 2.6Ω pull-up / 25ns rise time; BG drives bottom FET with 1.1Ω pull-down / 25ns fall time - supports fast switching with anti-shoot-through logic. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® compensation | Enables stable loop response across wide range of output capacitor ESR (1mΩ–100mΩ) and capacitance (10µF–1000µF), eliminating need for re-tuning per design. |
| Interleaved dual-phase architecture | Reduces input ripple current by ~70% vs single-phase, allowing smaller input capacitors and lower EMI without additional filtering. |
| Independent current foldback | ILIM pin configures per-channel current limit threshold (20/40/60 mV) - protects MOSFETs during short-circuit while preserving regulation under normal loads. |
| Pre-biased output support | Allows safe startup into pre-charged output capacitors without reverse current flow - critical for hot-swap and multi-rail sequencing applications. |
| Wide VIN range with robust protection | Operates from 4V–24V input; includes UVLO (3V) with 0.5V hysteresis, overvoltage lockout (0.84–0.88V on VFB), and switch-node voltage rating up to 30V. |
Applications
| High-Density Notebook Power | Portable Instrumentation |
|---|---|
|
Use Scenario: Dual-rail CPU core (1.8V/5A) and I/O (3.3V/5A) supply in space-constrained ultrabook designs. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing interleaved switching, phase alignment, and coordinated soft-start. Use Value: Reduces total input capacitance by 40% and lowers peak input ripple current, enabling thinner PCB stack-ups and extended battery runtime. |
Use Scenario: Battery-powered handheld oscilloscope requiring clean, low-noise 2.5V analog front-end and 3.3V digital logic rails. IC Role / Device Role / Timing Role: Dual-output controller with selectable Burst Mode® for ultra-low quiescent current (<50µA) during standby. Use Value: Achieves >92% efficiency at 10mA load via Burst Mode®, extending battery life beyond 12 hours without compromising 10mV output ripple. |
| DC Power Distribution Systems | Industrial Embedded Control |
|
Use Scenario: 12V-to-3.3V/2.5V conversion in modular PLC backplane with strict EMI limits and thermal constraints. IC Role / Device Role / Timing Role: Phase-locked dual controller synchronized to system clock to shift switching harmonics away from sensitive bands. Use Value: Enables compliance with CISPR-22 Class B EMI limits using only ceramic input caps and no ferrite beads. |
Use Scenario: Fanless industrial gateway requiring -40°C to 85°C operation, high reliability, and immunity to voltage transients. IC Role / Device Role / Timing Role: Robust dual controller with AEC-Q100 qualified variants, 30V switch-node rating, and undervoltage lockout hysteresis. Use Value: Survives 34V/500ms input transients (LTC3850I variant) and maintains regulation during brownouts via precise 3V UVLO with 0.5V hysteresis. |
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 |
|---|---|---|---|
| LTC3855IUFD#PBF | Includes integrated MOSFET drivers with higher peak current (4A vs 2A), enhanced current-mode stability, and improved light-load efficiency via adaptive burst mode. | Targeted at higher-current (>10A/channel) applications with tighter transient response requirements. | Select when needing higher gate drive strength or improved sub-100mA efficiency; requires minor layout revision due to different pinout and EXTVCC handling. |
| MP8765GL-Z | Single-chip dual-phase controller with integrated power MOSFETs (30V/15A), fixed 500kHz frequency, no PLL sync, and simpler feature set (no OPTI-LOOP®, no tracking). | Suitable for cost-sensitive, medium-power applications where board space is more critical than design flexibility. | Choose for simplified BOM and faster time-to-market where programmability and advanced compensation are not required. |
Compared with LTC3855IUFD#PBF, the LTC3850EUFD#PBF offers broader frequency tuning (250–780kHz vs fixed 500kHz) and superior transient optimization via OPTI-LOOP®, but lacks integrated FETs and higher drive capability. Versus MP8765GL-Z, it provides greater design adaptability for demanding industrial and portable applications at the cost of external MOSFET selection and layout complexity.
Availability
LTC3850EUFD#PBF is available at Aetrix Electronics and suitable for high-density notebook power, portable instrumentation, and DC power distribution systems requiring stable component supply, long-term lifecycle support, and guaranteed performance across –40°C to 85°C.
Supply support for LTC3850EUFD#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing (DSP) technologies, serving industrial, communications, computing, and automotive markets.
The LTC3850EUFD#PBF belongs to Analog Devices' Power by Linear™ family of high-efficiency DC/DC controllers, designed specifically for demanding multi-rail, high-current, and thermally constrained power conversion applications.
FAQ
What is the maximum supported switching frequency for the LTC3850EUFD#PBF?
The LTC3850EUFD#PBF supports a phase-lockable switching frequency range of 250kHz to 780kHz. At VFREQ = 2.4V or higher, the nominal frequency reaches 780kHz (typical), enabling compact magnetics and reduced output ripple. Frequency is set via a DC voltage on the FREQ/PLLFLTR pin or synchronized externally through the MODE/PLLIN pin.
Does the LTC3850EUFD#PBF support pre-biased output startup?
Yes, the LTC3850EUFD#PBF supports pre-biased output startup. Its current-mode architecture and reverse-current detection (IREV comparator) prevent negative inductor current flow during startup into an already charged output capacitor. This avoids output voltage overshoot and ensures safe, monotonic ramp-up even when VOUT is initially non-zero.
How does the ILIM pin affect current limiting on the LTC3850EUFD#PBF?
The ILIM pin on the LTC3850EUFD#PBF selects the maximum current sense threshold per channel: tying to SGND sets 20mV, floating sets 40mV, and connecting to INTVCC sets 60mV. This directly scales the foldback current limit without changing external sense components, allowing flexible short-circuit protection tuning for different MOSFET RDS(on) or shunt values.
Can the LTC3850EUFD#PBF operate with only one channel enabled?
Yes, the LTC3850EUFD#PBF supports independent channel control. Pulling RUN1 low disables Channel 1 while Channel 2 remains fully operational, and vice versa. Both channels share the same INTVCC supply and oscillator, but each has dedicated ITH, VFB, TK/SS, and SENSE pins - enabling asymmetric configurations such as 3.3V/5A + 1.2V/10A.
What thermal performance can be expected from the LTC3850EUFD#PBF in its UFD package?
The LTC3850EUFD#PBF in the 4mm × 5mm QFN package has a junction-to-ambient thermal resistance (θJA) of 34°C/W when mounted on a standard 4-layer PCB with 2-in² copper pour and soldered exposed pad. Under typical 5A/channel operation at 12VIN/3.3VOUT, junction temperature rise remains below 45°C, ensuring reliable operation within the –40°C to 85°C ambient range.
LTC3850EUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- 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):
- 4V ~ 24V
- Frequency - Switching:
- 250kHz ~ 780kHz
- Duty Cycle (Max):
- 97.2%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC3850EUFD#PBF FAQ
1.How can I place an order for LTC3850EUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3850EUFD#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 LTC3850EUFD#PBF reliable?
The price and inventory of LTC3850EUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3850EUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3850EUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3850EUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3850EUFD#PBF?
LTC3850EUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3850EUFD#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 LTC3850EUFD#PBF?
For technical support, including LTC3850EUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3850EUFD#PBF requirements.
6.How does Aetrix verify that LTC3850EUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3850EUFD#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 LTC3850EUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3850EUFD#PBF?
All LTC3850EUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3850EUFD#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 LTC3850EUFD#PBF part is unused and in its original packaging.
Return procedure for LTC3850EUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3850EUFD#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…
