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Analog Devices Inc. LTC3858EUFD-1#TRPBF
- Part No.:
- LTC3858EUFD-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3858EUFD-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,522
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Product details
Overview
LTC3858EUFD-1#TRPBF from Analog Devices (formerly Linear Technology) is a dual-phase, synchronous step-down DC/DC controller IC driving two independent N-channel MOSFET stages. It delivers 0.8V–24V output voltage per channel, supports 4V–38V input, operates at 75kHz–850kHz with phase-lock capability, and achieves 170μA no-load quiescent current - enabling high-efficiency power conversion in battery-powered digital systems.
For engineers reviewing the LTC3858EUFD-1#TRPBF datasheet, LTC3858EUFD-1#TRPBF pinout, LTC3858EUFD-1#TRPBF application, or LTC3858EUFD-1#TRPBF equivalent, key selection considerations include out-of-phase dual-channel operation for reduced input ripple, OPTI-LOOP® compensation for wide capacitor/ESR tolerance, selectable light-load modes (Burst Mode®, pulse-skipping, forced continuous), and integrated output overvoltage and short-circuit latchoff protection.
Technical Context
The LTC3858EUFD-1#TRPBF implements a constant-frequency current-mode architecture with two independent control loops operating 180° out of phase to minimize input capacitance requirements and supply-induced noise. Each channel features dedicated ITH, SS, VFB, SENSE+, SENSE−, RUN, PGOOD, and gate drive pins (TG/BG/BOOST/SW), enabling fully independent regulation and sequencing.
It integrates dual internal LDOs powering gate drivers from either VIN or EXTVCC (switchover at 4.7V), supports RSENSE or DCR current sensing, and includes precision 0.800V ±1.5% feedback reference, programmable soft-start, and a dedicated short-circuit latchoff timer using the SS pin with arming (2.0V) and latchoff (1.5V) thresholds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 38V - supports wide intermediate bus voltages and battery chemistries including 12V, 24V, and 36V nominal systems. |
| Output Voltage Range | 0.8V to 24V per channel - enables generation of core logic (0.8V–1.2V), I/O (1.8V–3.3V), and auxiliary rails (5V–12V) from single controller. |
| No-Load Quiescent Current | 170μA (one channel active) - extends runtime in always-on or low-duty-cycle battery-operated devices. |
| Switching Frequency Range | 75kHz to 850kHz (phase-lockable) - allows EMI optimization and compact magnetics design while maintaining stability across load/transient conditions. |
| Feedback Reference Voltage | 0.800V ±1.5% (–40°C to 125°C) - ensures accurate output regulation across automotive and industrial temperature ranges. |
| Gate Driver Strength | TG pull-up: 2.5Ω; BG pull-down: 1.1Ω - supports fast switching of high-side and low-side N-MOSFETs up to ~5A per phase with minimal dead-time loss. |
| Short-Circuit Protection | SS-pin-based latchoff with 2.0V arming / 1.5V trip - provides deterministic shutdown during sustained overload without external circuitry. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN with exposed thermal pad (Pin 29 = SGND). Requires soldering of exposed pad to PCB for thermal performance (θJA = 43°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+, SENSE2+ | Differential current sense (+) inputs | Connect to DCR network or RSENSE to set peak current limit; referenced to SENSE− for accurate current mode control. |
| SENSE1−, SENSE2− | Differential current sense (−) inputs | Return path for current sensing; supplies bias current when > INTVCC − 0.5V - enables high-side sensing configurations. |
| TG1, TG2 | Top-gate N-MOSFET drivers | Floating outputs swinging from SW node + (INTVCC − 0.5V); require bootstrap capacitors for high-side gate drive. |
| BG1, BG2 | Bottom-gate N-MOSFET drivers | GND-referenced outputs swinging from 0V to INTVCC; directly drive synchronous rectifier MOSFETs. |
| SW1, SW2 | Switch node connections | High dv/dt nodes connecting to inductor center taps; must be routed with minimal loop area to reduce EMI. |
| VFB1, VFB2 | Feedback voltage inputs | Compare output voltage (via resistive divider) to 0.800V reference; enable precise regulation and remote sensing. |
| ITH1, ITH2 | Error amplifier outputs | Analog control voltage setting current limit threshold; used for loop compensation and current foldback during fault conditions. |
| SS1, SS2 | Soft-start / latchoff timer inputs | Internal 1μA pull-up charges external capacitor for controlled ramp-up; also discharges at 9μA during short-circuit to trigger latchoff. |
| RUN1, RUN2 | Independent channel enable inputs | Digital logic-level controls: <1.26V disables channel; both <0.7V enters ultra-low-IQ shutdown (8μA). |
| PGOOD1 | Open-drain power-good indicator | Asserts low when VFB1 deviates >±10% from target - signals system controller that rail is stable and within spec. |
| FREQ | Frequency programming input | 20μA internal pull-up sets oscillator frequency; resistor to GND programs 50kHz–900kHz; tie to GND/INTVCC for fixed 350/535kHz. |
| PLLIN/MODE | Synchronization & light-load mode select | Accepts external clock for phase-locking; logic level selects Burst Mode® (GND), pulse-skipping (1.2V–INTVCC−1.3V), or forced continuous (INTVCC). |
| VIN, PGND, SGND | Main input, power ground, signal ground | VIN powers internal LDO; PGND connects to MOSFET sources; SGND is isolated analog reference - critical for noise immunity. |
| INTVCC, EXTVCC | Internal LDO output & external bias input | INTVCC = 5.1V regulated supply for logic/drivers; EXTVCC >4.7V bypasses VIN LDO for higher efficiency (e.g., powered from own output). |
| BOOST1, BOOST2 | Bootstrap supply inputs | Capacitor-connected between BOOST and SW; diode-fed from INTVCC - sustains top-gate drive during 99% duty cycle dropout operation. |
Key Features
| Feature | Design Value |
|---|---|
| Out-of-phase dual-channel operation | Reduces RMS input ripple current by ~70%, allowing smaller input capacitors and lower ESR requirements in distributed power systems. |
| OPTI-LOOP® compensation | Enables stable loop response across wide range of output capacitor values (10μF–1000μF) and ESR (0.5mΩ–100mΩ) without redesign. |
| Selectably optimized light-load efficiency | Burst Mode® (170μA IQ), pulse-skipping, or forced continuous operation lets designers trade off ripple vs. efficiency based on real-time load profile. |
| 99% maximum duty cycle operation | Supports ultra-low dropout regulation (e.g., 12V→11.5V) without external components - critical for post-regulation in automotive cold-crank scenarios. |
| Dual independent short-circuit latchoff | Each channel uses its own SS pin for autonomous fault detection and shutdown - prevents single-point failure from propagating across rails. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Dual-rail power for SoC core (0.85V/3A) and interface peripherals (3.3V/2A) in head-unit ECUs under 12V battery input with cold-crank down to 4.5V. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing independent voltage rails with coordinated sequencing and fault isolation. Use Value: 170μA quiescent current extends standby time; 99% duty cycle maintains 3.3V output during 5V battery dips; PGOOD1 enables safe processor boot sequence. | Use Scenario: Compact 24V-to-5V/3.3V conversion for fieldbus communication modules requiring high reliability and EMC robustness in factory automation cabinets. IC Role / Device Role / Timing Role: Dual-channel controller delivering isolated, regulated outputs with out-of-phase switching to meet CISPR-22 conducted emission limits. Use Value: Phase interleaving cuts input ripple amplitude by 50%; OPTI-LOOP® eliminates need for custom compensation per capacitor batch; latchoff protects against wiring faults. |
| Portable Medical Imaging Sensor Hub | Telecom Remote Radio Unit (RRU) |
Use Scenario: Battery-powered ultrasound sensor array requiring low-noise 1.2V analog rail and 1.8V digital rail from Li-ion (3.0–4.2V) input with strict 24-hour runtime target. IC Role / Device Role / Timing Role: High-efficiency dual-buck controller operating in Burst Mode® to minimize idle power loss while supporting rapid transient response. Use Value: 170μA IQ doubles battery life vs. conventional controllers; independent soft-start prevents inrush into sensitive analog circuitry; 0.800V reference ensures ADC accuracy. | Use Scenario: Distributed 48V intermediate bus powering multiple RF front-end stages (5V, 3.3V, 1.2V) in outdoor macro-cell base stations with -40°C to +85°C ambient requirement. IC Role / Device Role / Timing Role: Dual-phase controller configured as master-slave for staggered start-up and thermal load balancing across parallel converter sections. Use Value: Wide –40°C to 125°C junction rating ensures reliability; EXTVCC input allows self-biasing from local 5V rail to improve overall system efficiency; phase-locking synchronizes to system clock for EMI reduction. |
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 MOSFET drivers only (no external FET support); 4.5V–16V VIN; fixed 0.6V reference; no EXTVCC or latchoff. | Targeted at cost-sensitive, space-constrained consumer applications - lacks automotive-grade temp range and fault protection depth. | Choose MP2918GL-Z only for low-complexity, low-voltage (<16V) designs where integrated FETs suffice and latchoff is not required. |
| LTC3855IUFD#TRPBF | Single-phase version with identical pinout, IQ (170μA), and feature set except dual-channel functionality; supports same VIN/VOUT ranges and light-load modes. | Used when only one regulated rail is needed - shares layout compatibility but requires separate controllers for multi-rail systems. | Choose LTC3855IUFD#TRPBF for single-rail designs or when board space allows duplication; retains full feature parity except channel count. |
Compared with MP2918GL-Z and LTC3855IUFD#TRPBF, the LTC3858EUFD-1#TRPBF uniquely combines dual independent channels, 4V–38V input flexibility, EXTVCC biasing, and hardware-enforced short-circuit latchoff - making it the only option qualified for demanding automotive and industrial dual-rail systems requiring functional safety margins.
Availability
LTC3858EUFD-1#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC I/O modules, portable medical imaging hubs, and telecom remote radio units requiring stable component supply, long-term lifecycle assurance, and AEC-Q200-aligned reliability.
Supply support for LTC3858EUFD-1#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 full product support, datasheets, and application engineering for legacy Linear parts including the LTC3858 series.
The LTC3858 family was designed for high-efficiency, dual-output DC/DC conversion in battery-powered, automotive, and industrial systems where low quiescent current, wide input range, and robust fault protection are mandatory.
FAQ
What is the minimum input voltage supported by the LTC3858EUFD-1#TRPBF?
The LTC3858EUFD-1#TRPBF supports an input voltage range of 4V to 38V. Its undervoltage lockout (UVLO) activates below 3.6V (rising) and releases above 4.0V (falling), ensuring reliable startup from weak or cold-cranked batteries. Operation below 4V is not guaranteed and may result in undefined behavior or failure to regulate.
Does the LTC3858EUFD-1#TRPBF support phase synchronization with an external clock?
Yes, the LTC3858EUFD-1#TRPBF supports phase synchronization via the PLLIN/MODE pin. When an external clock signal is applied to this pin, the internal phase-locked loop aligns the rising edge of TG1 with the rising edge of the external clock. The device accepts synchronization frequencies from 75kHz to 850kHz and maintains lock across temperature and line variations.
How does the short-circuit latchoff function work on the LTC3858EUFD-1#TRPBF?
The LTC3858EUFD-1#TRPBF implements per-channel short-circuit latchoff using the SS1 and SS2 pins. Once the SS voltage exceeds 2.0V (arming threshold), a 9μA discharge current pulls SS down if VFB drops below 70% of regulation. If SS falls below 1.5V, the channel latches off until VIN or RUN is cycled. This hardware-based protection requires no external components and operates independently per channel.
Can the LTC3858EUFD-1#TRPBF operate with only one channel enabled?
Yes, the LTC3858EUFD-1#TRPBF supports independent channel control via RUN1 and RUN2. Driving RUN1 high and RUN2 low enables only Channel 1, drawing just 170μA quiescent current. Both channels can be disabled simultaneously (RUN1/RUN2 <0.7V) to achieve 8μA shutdown current - ideal for system-level power gating.
What is the purpose of the EXTVCC pin on the LTC3858EUFD-1#TRPBF?
The EXTVCC pin on the LTC3858EUFD-1#TRPBF provides an alternative power source for the internal 5.1V INTVCC LDO. When EXTVCC exceeds 4.7V, the VIN-powered LDO shuts off and the EXTVCC LDO takes over - enabling higher overall efficiency by powering the controller from one of its own regulated outputs (e.g., 5V rail) instead of the raw input bus.
LTC3858EUFD-1#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 ~ 38V
- Frequency - Switching:
- 105kHz ~ 835kHz, 350kHz ~ 535kHz
- Duty Cycle (Max):
- 99.4%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC3858EUFD-1#TRPBF FAQ
1.How can I place an order for LTC3858EUFD-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3858EUFD-1#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 LTC3858EUFD-1#TRPBF reliable?
The price and inventory of LTC3858EUFD-1#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3858EUFD-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3858EUFD-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3858EUFD-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3858EUFD-1#TRPBF?
LTC3858EUFD-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3858EUFD-1#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 LTC3858EUFD-1#TRPBF?
For technical support, including LTC3858EUFD-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3858EUFD-1#TRPBF requirements.
6.How does Aetrix verify that LTC3858EUFD-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3858EUFD-1#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 LTC3858EUFD-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3858EUFD-1#TRPBF?
All LTC3858EUFD-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3858EUFD-1#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 LTC3858EUFD-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC3858EUFD-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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