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Analog Devices Inc. LTC3850IUFD#TRPBF
- Part No.:
- LTC3850IUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3850IUFD#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,963
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Product details
Overview
LTC3850IUFD#TRPBF 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 4V–24V input, provides ±1% 0.8V reference accuracy, and operates at phase-lockable frequencies from 250kHz to 780kHz - enabling high-density DC/DC conversion for portable computing and battery-powered instrumentation.
For engineers reviewing the LTC3850IUFD#TRPBF datasheet, LTC3850IUFD#TRPBF pinout, LTC3850IUFD#TRPBF application, or LTC3850IUFD#TRPBF equivalent, this page details confirmed dual-phase current-mode control, RSENSE/DCR sensing capability, OPTI-LOOP® compensation, independent soft-start/tracking, and automotive-grade thermal performance in the 4mm × 5mm QFN package.
Technical Context
The LTC3850IUFD#TRPBF implements constant-frequency current-mode control with two independent 180° out-of-phase channels, each featuring an error amplifier with transconductance of 2.2 mmho and a precision 0.8V feedback reference (±1% over temperature). Its ITH pin directly modulates peak inductor current via voltage-controlled current comparator threshold, while MODE/PLLIN selects among Burst Mode®, pulse-skipping, or forced continuous conduction.
Phase synchronization is achieved via FREQ/PLLFLTR pin-based frequency programming or external clock injection into MODE/PLLIN, supporting coherent multi-phase operation. The IC integrates dual N-channel gate drivers (TG/BG) with 25ns transition times, 1.5Ω/1.1Ω pull-down on BG, and 2.6Ω/2.4Ω pull-up on TG - optimized for low-loss synchronous rectification without external bootstrap diodes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 24V (28V absolute max); supports wide battery chemistries and intermediate bus rails without derating. |
| Output Voltage Accuracy | ±1% at 0.8V reference; ensures tight regulation across load, line, and temperature for sensitive digital loads. |
| Switching Frequency | 250kHz to 780kHz, phase-lockable; balances efficiency vs. magnetics size - e.g., 500kHz enables compact 2.2µH inductors. |
| Efficiency | Up to 95% at full load; achieved via low-RDS(on) gate drive, minimized dead-time losses, and optimized current sensing. |
| Current Sensing | RSENSE or DCR-compatible; supports three programmable sense thresholds (20/40/60mV) via ILIM pin configuration. |
| Thermal Performance | θJA = 34°C/W in UFD package; enables 5A per channel operation at 85°C ambient without forced air. |
| Power Good Output | Open-drain PGOOD with ±7.5% trip window and 17µs mask timer; provides reliable system-level power sequencing feedback. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN with exposed pad (Pin 29), RoHS-compliant, rated for –40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2 | Independent channel enable inputs | 1.22V threshold with hysteresis; allows staggered startup or fault-isolated shutdown per channel. |
| TK/SS1, TK/SS2 | Soft-start and tracking inputs | 1.3µA internal charge current; enables linear VOUT ramp or precise voltage tracking between rails. |
| SENSE1+/–, SENSE2+/– | Differential current sense inputs | ±2µA bias current; supports Kelvin-connected resistive or DCR-based sensing with common-mode range up to VIN. |
| VFB1, VFB2 | Error amplifier feedback inputs | 0.8V regulated reference point; connects to resistor divider for output voltage setting with remote sensing capability. |
| TG1, TG2 / BG1, BG2 | Top/bottom N-MOSFET gate drivers | Integrated 5V drivers with <25ns transitions; eliminates need for external level shifters or discrete drivers. |
| BOOST1, BOOST2 | Floating bootstrap supply terminals | Supports self-biasing of high-side drivers; swings from INTVCC–0.7V to VIN+INTVCC for full N-MOSFET utilization. |
| MODE/PLLIN | Mode selection & external sync input | Configures Burst Mode® (float), pulse-skip (INTVCC), or forced CCM (SGND); accepts external clock for deterministic phase alignment. |
| FREQ/PLLFLTR | Oscillator frequency control | DC voltage input sets nominal frequency; also serves as PLL loop filter node when synchronized externally. |
| PGOOD | Power-good status indicator | Open-drain output asserts low if either VOUT deviates >±7.5% for >17µs - critical for FPGA/CPU power sequencing. |
| ILIM | Current limit threshold select | Three levels (20/40/60mV) set by tying to SGND/FLOAT/INTVCC - enables scalable overcurrent protection per design margin. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® compensation | Enables stable loop response across wide range of output capacitor ESR and capacitance values - simplifies output filter design without re-tuning. |
| Dual 180° phased control | Reduces input ripple current by ~70% versus single-phase, cutting required input capacitance and lowering EMI emissions. |
| Pre-biased output support | Allows safe startup into pre-charged outputs - essential for hot-swap and rail-stacking applications without reverse current damage. |
| Independent channel control | Each channel has dedicated RUN, TK/SS, and ITH pins - enables asymmetric configurations (e.g., 3.3V/1.8V with different soft-start timing). |
| Automotive qualification | AEC-Q100 qualified (Grade 3); validated for –40°C to +85°C operation with robust transient immunity and long-term reliability. |
Applications
| High-Efficiency Dual-Core CPU Power | Notebook System Rail Sequencing |
|---|---|
|
Use Scenario: Powering dual-core processors requiring tightly regulated 1.2V and 1.05V rails with fast transient response and low quiescent current. IC Role / Device Role / Timing Role: Dual-phase controller managing independent buck converters with coordinated soft-start and PGOOD signaling. Use Value: Achieves 94% efficiency at 5A per rail while maintaining <±1% output accuracy and enabling seamless core voltage scaling. |
Use Scenario: Generating and sequencing 3.3V, 2.5V, and 1.8V rails in ultraportable notebooks with strict power-up timing requirements. IC Role / Device Role / Timing Role: Dual controller with independent TK/SS pins implementing precise voltage ramp tracking and inter-rail delay coordination. Use Value: Eliminates need for external sequencing ICs by using internal RUN/TK/SS logic to meet Intel VRD timing specs within ±1ms tolerance. |
| Battery-Powered Test Equipment | Industrial DC Distribution Module |
|
Use Scenario: Supplying isolated analog front-end (2.5V) and digital logic (3.3V) rails from a single 12V Li-ion battery pack in handheld meters. IC Role / Device Role / Timing Role: Dual synchronous buck controller delivering high PSRR and low noise across both rails with shared input filtering. Use Value: Delivers <10mVpp output ripple and 95% peak efficiency - extending battery life while preserving ADC resolution. |
Use Scenario: Centralized 24V-to-12V/5V conversion in DIN-rail mounted industrial controllers with redundant power monitoring. IC Role / Device Role / Timing Role: Dual-phase controller with open-drain PGOOD outputs feeding PLC watchdog inputs for real-time rail health verification. Use Value: Enables single-board dual-output solution with fault isolation - failure of one channel does not disrupt the other's regulation or reporting. |
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 |
|---|---|---|---|
| MP2918GL-Z | Single-chip dual-phase controller with integrated MOSFETs; fixed 500kHz frequency; no external RSENSE option. | Suitable for space-constrained designs where board area > efficiency optimization; lacks DCR sensing and frequency tuning. | Select MP2918GL-Z only when integrated FETs reduce BOM count and thermal management permits 3A/channel limits. |
| ISL95836IRZ-T | Intel VR12.5-compliant dual-phase controller; supports adaptive voltage positioning (AVP); requires external PMBus interface. | Targeted at CPU VRMs with dynamic VID updates; includes telemetry but adds complexity for non-Intel platforms. | Choose ISL95836IRZ-T only for Intel mobile CPU applications requiring AVP and PMBus telemetry integration. |
Compared with MP2918GL-Z and ISL95836IRZ-T, the LTC3850IUFD#TRPBF offers broader input range (4–24V), flexible current sensing (RSENSE/DCR), and manual frequency tuning - making it optimal for custom industrial and test equipment where design flexibility outweighs integration convenience.
Availability
LTC3850IUFD#TRPBF is available at Aetrix Electronics and suitable for notebook computers, portable instrumentation, and battery-operated digital devices requiring stable component supply, automotive-grade reliability, and dual-rail power management.
Supply support for LTC3850IUFD#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3850IUFD#TRPBF belongs to Analog Devices' Power by Linear™ controller family, engineered for high-efficiency, low-noise, multi-phase DC/DC conversion in space- and thermally constrained portable and embedded systems.
FAQ
What is the maximum input voltage rating for the LTC3850IUFD#TRPBF?
The LTC3850IUFD#TRPBF has an absolute maximum input voltage (VIN) rating of 28V. Its recommended operating range is 4V to 24V, with transient tolerance up to 34V for <500ms only in the LTC3850I grade - which applies to the LTC3850IUFD#TRPBF. Exceeding 28V continuously risks permanent damage to internal circuitry and gate drivers.
Does the LTC3850IUFD#TRPBF support pre-biased output startup?
Yes, the LTC3850IUFD#TRPBF supports pre-biased output startup. Its current-mode architecture and controlled top-FET turn-on prevent reverse current flow during startup into an already charged output capacitor - a key requirement for hot-swap and rail-stacking applications where output voltage may be present before enable.
How is phase synchronization implemented on the LTC3850IUFD#TRPBF?
Phase synchronization on the LTC3850IUFD#TRPBF is implemented via the MODE/PLLIN pin, which functions as both a mode selector and external clock input. When driven by an external square wave, the internal oscillator locks to that frequency and phase, enabling deterministic multi-phase operation across multiple LTC3850IUFD#TRPBF units or with other compatible controllers.
What are the three current sense threshold options on the LTC3850IUFD#TRPBF and how are they selected?
The LTC3850IUFD#TRPBF offers three programmable current sense thresholds: 20mV (ILIM = SGND), 40mV (ILIM = FLOAT), and 60mV (ILIM = INTVCC). These settings adjust the maximum allowable sense voltage before foldback limiting activates - allowing designers to optimize MOSFET RDS(on) trade-offs and short-circuit protection margins per channel.
Can the LTC3850IUFD#TRPBF operate with only one channel enabled?
Yes, the LTC3850IUFD#TRPBF supports independent channel operation. Pulling RUN1 low disables Channel 1 while leaving Channel 2 fully functional - including its gate drivers, feedback loop, and PGOOD assertion. This enables asymmetric power architectures, such as powering a main SoC rail while keeping a standby rail active for wake-on-LAN or RTC functions.
LTC3850IUFD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-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):
- 4V ~ 30V
- 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)
LTC3850IUFD#TRPBF FAQ
1.How can I place an order for LTC3850IUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3850IUFD#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 LTC3850IUFD#TRPBF reliable?
The price and inventory of LTC3850IUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3850IUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3850IUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3850IUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3850IUFD#TRPBF?
LTC3850IUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3850IUFD#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 LTC3850IUFD#TRPBF?
For technical support, including LTC3850IUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3850IUFD#TRPBF requirements.
6.How does Aetrix verify that LTC3850IUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3850IUFD#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 LTC3850IUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3850IUFD#TRPBF?
All LTC3850IUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3850IUFD#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 LTC3850IUFD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3850IUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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