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Analog Devices Inc. LTC3868IUFD-1#TRPBF
- Part No.:
- LTC3868IUFD-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3868IUFD-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,475
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Product details
Overview
LTC3868IUFD-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–14V output voltage with 4V–24V input range, 170μA quiescent current in single-channel sleep mode, and phase-locked switching up to 850kHz - enabling high-efficiency, low-noise power conversion in portable battery-powered systems.
For engineers reviewing the LTC3868IUFD-1#TRPBF datasheet, LTC3868IUFD-1#TRPBF pinout, LTC3868IUFD-1#TRPBF application, or LTC3868IUFD-1#TRPBF equivalent, key selection criteria include out-of-phase dual-channel operation for reduced input capacitance, OPTI-LOOP® compensation for wide output capacitor ESR tolerance, selectable light-load modes (Burst Mode®, pulse-skipping, forced continuous), and integrated short-circuit latchoff with soft-start timing control.
Technical Context
The LTC3868IUFD-1#TRPBF implements a constant-frequency current-mode architecture with two 180° out-of-phase controllers, minimizing input ripple and EMI. Its transconductance error amplifier (2 mmho) and precision 0.8V reference (±12 mV over temperature) enable tight regulation across load and line variations.
It supports RSENSE or DCR current sensing, features independent ITH pins per channel for current limit control, and integrates dual gate drivers (TG/BG) with 1.1–2.5Ω on-resistance and sub-30ns transition times - optimized for fast, efficient N-MOSFET switching in high-current step-down topologies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 24V - supports wide intermediate bus voltages and multi-cell Li-ion, Li-polymer, or lead-acid battery inputs. |
| Output Voltage Range | 0.8V to 14V - programmable via external resistor divider; regulated by 0.8V ±12 mV reference. |
| Quiescent Current | 170μA (one channel active, sleep mode) - extends runtime in always-on or low-duty-cycle portable devices. |
| Switching Frequency | 75kHz to 850kHz (phase-lockable); 50kHz to 900kHz (programmable) - enables compact magnetics and noise-sensitive layout optimization. |
| Duty Cycle Max | 99.4% - supports ultra-low dropout operation (e.g., 5V→4.95V), critical for high-VIN, low-VOUT applications. |
| Current Sense Threshold | 43–57 mV (max) - sets accurate overcurrent protection with minimal power loss in sense resistors or DCR networks. |
| Shutdown IQ | 8μA - ensures near-zero power draw during system standby or deep-sleep states. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN with exposed pad (Pin 29 = SGND). Thermal resistance θJA = 43°C/W. Exposed pad must be soldered to PCB for rated thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+, SENSE2+ | Differential current sense (+) input | Connects to high-side of RSENSE or DCR network; sets peak current limit with SENSE–. |
| SENSE1–, SENSE2– | Differential current sense (–) input | Reference node for current comparator; supplies bias current above INTVCC – 0.5V. |
| TG1, TG2 | Top N-MOSFET gate driver output | Floating driver with swing = INTVCC – 0.5V superimposed on SW node; drives high-side switch. |
| BG1, BG2 | Bottom N-MOSFET gate driver output | Ground-referenced driver (0V to INTVCC); controls synchronous rectifier conduction. |
| VFB1, VFB2 | Feedback input for output voltage regulation | Compares remote-sensed output to internal 0.8V reference; determines regulation setpoint. |
| ITH1, ITH2 | Error amplifier output / current limit control | Analog control voltage (0.425V–2V) setting per-channel peak inductor current threshold. |
| SS1, SS2 | Soft-start and short-circuit latchoff timer | Internal 1μA pull-up charges external capacitor; voltage ramp controls startup slew rate and enables latchoff timeout. |
| PGOOD1 | Open-drain power-good indicator | Asserts low when VFB1 deviates >±10% from target - signals valid output for downstream logic sequencing. |
| RUN1, RUN2 | Independent channel enable/disable | Digital control: <1.26V disables channel; both <0.7V forces full shutdown (8μA IQ). |
| PLLIN/MODE | Light-load mode select & sync input | GND = Burst Mode®; INTVCC = forced continuous; 1.2V–(INTVCC–1.3V) = pulse-skipping; external clock = synchronization. |
Key Features
| Feature | Design Value |
|---|---|
| Out-of-phase dual controllers | Reduces RMS input ripple current by ~70%, allowing smaller input bulk capacitors and lower EMI. |
| OPTI-LOOP® compensation | Enables stable loop response across wide range of output capacitor values and ESR (e.g., ceramic + polymer hybrids). |
| Programmable light-load operation | Selectable Burst Mode®, pulse-skipping, or forced continuous mode - optimizes efficiency vs. noise trade-off per application need. |
| Short-circuit latchoff with arming | SS pin voltage >2V arms protection; falling below 1.5V triggers shutdown - prevents thermal runaway without manual reset. |
| Integrated INTVCC LDO with EXTVCC switchover | Auto-selects between VIN- and EXTVCC-derived 5.1V supply - improves overall system efficiency when powering INTVCC from a regulated rail. |
Applications
| Portable Medical Instrumentation | Notebook & Ultrabook Power Rails |
|---|---|
Use Scenario: Dual-rail power for FPGA + ADC subsystem in handheld ultrasound or glucose monitor. IC Role / Device Role: Dual-phase controller generating isolated 3.3V (digital core) and 8.5V (analog front-end) from single 12V battery pack. Use Value: 170μA sleep IQ extends battery life; out-of-phase operation minimizes conducted EMI into sensitive analog signal paths. |
Use Scenario: Main system power delivery in thin-and-light notebooks with strict thermal envelope. IC Role / Device Role: High-efficiency dual-output buck controller supplying CPU core (0.85V) and DDR memory (1.2V) rails. Use Value: 99.4% max duty cycle enables operation down to 5V input; OPTI-LOOP® ensures stability with low-ESR ceramic output caps. |
| Battery-Powered Test Equipment | Distributed DC Power Systems |
Use Scenario: Portable oscilloscope or multimeter requiring clean, low-noise analog and digital supplies. IC Role / Device Role: Dual-channel controller delivering 5V (logic) and ±15V (op-amp rails via charge pump) from 19.2V Li-ion pack. Use Value: Phase-locked frequency (75–850kHz) allows EMI filtering at known harmonics; PGOOD1 enables safe power sequencing. |
Use Scenario: Intermediate bus converter in industrial IoT gateway with multiple isolated DC-DC modules. IC Role / Device Role: Primary 24V→5V/3.3V regulator feeding secondary isolated converters and microcontroller subsystems. Use Value: Wide 4–24V input accommodates varying upstream sources; latchoff protection prevents cascade failure in distributed architectures. |
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 | Fixed 600kHz frequency only; no PLL sync; 200μA IQ (single channel); no EXTVCC switchover. | Lacks programmable light-load modes and phase synchronization - less flexible in noise-sensitive or synchronized multi-rail systems. | Choose for cost-sensitive, fixed-frequency designs where Burst Mode® and external clock sync are unnecessary. |
| ISL95836IRZ-T | Supports 3-phase interleaving; higher max VIN (36V); 250μA IQ; no soft-start latchoff or OPTI-LOOP®. | Targeted at CPU VRMs; lacks short-circuit latchoff and robust soft-start timing - unsuitable for unattended battery systems. | Prefer for high-current, high-input-voltage server/desktop applications requiring 3-phase capability and tighter transient response. |
Compared with MP2918GL-Z and ISL95836IRZ-T, the LTC3868IUFD-1#TRPBF uniquely combines ultra-low IQ, phase-lockable frequency, OPTI-LOOP® adaptability, and autonomous short-circuit latchoff - making it optimal for portable, battery-critical, and thermally constrained dual-rail systems.
Availability
LTC3868IUFD-1#TRPBF is available at Aetrix Electronics and suitable for notebook computers, portable medical instrumentation, and battery-operated test equipment requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature grade (–40°C to +85°C).
Supply support for LTC3868IUFD-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 its high-performance power management portfolio with rigorous reliability testing and automotive-grade qualification pathways.
The LTC3868IUFD-1#TRPBF belongs to Linear's high-efficiency dual-phase controller product line, designed specifically for space-constrained, battery-powered applications demanding low quiescent current, precise regulation, and robust fault protection.
FAQ
What is the operating temperature range for the LTC3868IUFD-1#TRPBF?
The LTC3868IUFD-1#TRPBF is specified and guaranteed over the industrial temperature range of –40°C to +85°C. This rating applies to the "I" grade device in the 4mm × 5mm QFN package (UFD), with thermal performance validated using θJA = 43°C/W and mandatory soldering of the exposed pad (Pin 29) to PCB ground.
How does the LTC3868IUFD-1#TRPBF achieve ultra-low quiescent current?
The LTC3868IUFD-1#TRPBF achieves 170μA quiescent current in single-channel sleep mode through dynamic circuit disabling: when ITH voltage drops below 0.425V, internal sleep logic shuts down gate drivers, oscillator, and most bias circuits while retaining feedback monitoring. Full shutdown (8μA) occurs only when both RUN pins fall below 0.7V.
Can the LTC3868IUFD-1#TRPBF drive MOSFETs directly without external drivers?
Yes - the LTC3868IUFD-1#TRPBF integrates dual high-current gate drivers: TG1/TG2 (top-side, floating) and BG1/BG2 (bottom-side, ground-referenced), each capable of sourcing/sinking >1A peak current with 1.1–2.5Ω on-resistance. It is designed for direct connection to standard N-channel MOSFETs in synchronous buck topologies.
What protection features does the LTC3868IUFD-1#TRPBF include?
The LTC3868IUFD-1#TRPBF includes output overvoltage protection (via VFB monitoring), output short-circuit latchoff (SS-pin-based timeout), adjustable current limit (via ITH), undervoltage lockout (3.6–4.2V INTVCC), and foldback current limiting during overload. All protections operate independently per channel without external components.
Is the LTC3868IUFD-1#TRPBF pin-compatible with the LTC3868-1 variants in SSOP packages?
No - the LTC3868IUFD-1#TRPBF uses a 28-lead 4mm × 5mm QFN (UFD) package with different pinout and thermal characteristics versus the 28-lead SSOP (GN) variants. Pin mapping differs significantly (e.g., FREQ and PLLIN/MODE positions), and the QFN requires exposed-pad soldering; PCB layout and thermal design are not interchangeable.
LTC3868IUFD-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 ~ 24V
- 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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC3868IUFD-1#TRPBF FAQ
1.How can I place an order for LTC3868IUFD-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3868IUFD-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 LTC3868IUFD-1#TRPBF reliable?
The price and inventory of LTC3868IUFD-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 LTC3868IUFD-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3868IUFD-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3868IUFD-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3868IUFD-1#TRPBF?
LTC3868IUFD-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3868IUFD-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 LTC3868IUFD-1#TRPBF?
For technical support, including LTC3868IUFD-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3868IUFD-1#TRPBF requirements.
6.How does Aetrix verify that LTC3868IUFD-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3868IUFD-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 LTC3868IUFD-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3868IUFD-1#TRPBF?
All LTC3868IUFD-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3868IUFD-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 LTC3868IUFD-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC3868IUFD-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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