My Inquiry
My Account
Analog Devices Inc. LTC3868IUFD-1#PBF
- Part No.:
- LTC3868IUFD-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3868IUFD-1#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,418
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3868IUFD-1#PBF 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 across 4V–24V input, supports RSENSE or DCR current sensing, operates out-of-phase to reduce input ripple, and achieves 170μA quiescent current in single-channel sleep mode - ideal for battery-powered portable instruments and distributed power systems.
For engineers reviewing the LTC3868IUFD-1#PBF datasheet, LTC3868IUFD-1#PBF pinout, LTC3868IUFD-1#PBF application, or LTC3868IUFD-1#PBF equivalent, key selection considerations include its dual-channel phase-shifted operation, OPTI-LOOP® compensation, programmable 50kHz–900kHz switching frequency, selectable light-load modes (Burst Mode®, pulse-skipping, forced continuous), and integrated short-circuit latchoff with adjustable soft-start.
Technical Context
The LTC3868IUFD-1#PBF implements a constant-frequency current-mode control architecture with two independent 180° out-of-phase controllers, minimizing input capacitor ESR losses and power supply noise. Its error amplifier outputs (ITH1/ITH2) directly set per-channel peak current thresholds via differential sense amplifiers referenced to SENSE+ and SENSE− pins.
It integrates dual gate drivers (TG1/BG1 and TG2/BG2) with 2.5Ω pull-up / 1.5Ω pull-down on top-side and 2.4Ω / 1.1Ω on bottom-side drivers, supports external EXTVCC switchover at 4.7V, and features precision 0.8V ±1.5% feedback reference with ±5nA input bias - enabling accurate regulation across wide load and line variations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 24V - supports 12V intermediate bus and multi-cell Li-ion battery inputs without external pre-regulation. |
| Output Voltage Range | 0.8V to 14V - programmable via external resistor divider; 0.8V ±1.5% reference enables tight regulation at low VOUT. |
| Quiescent Current | 170μA (one channel active, sleep mode) - extends runtime in always-on portable instrumentation. |
| Switching Frequency | 50kHz to 900kHz (programmable) - allows optimization of size (high fSW) vs. efficiency (low fSW) per application. |
| Current Sensing | RSENSE or DCR - eliminates sense resistor loss in high-current designs; supports up to 57mV max sense threshold. |
| Duty Cycle Max | 99.4% - enables ultra-low dropout operation near VIN = VOUT, critical for battery end-of-life support. |
| Protection Features | Output overvoltage lockout (±13%), short-circuit latchoff, foldback current limiting, and PGOOD1 monitoring - ensures robust system-level fault handling. |
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 performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+, SENSE2+ | Differential current sense (+) input | Connects to DCR network or RSENSE top; sets current limit threshold with ITH voltage and SENSE− offset. |
| SENSE1−, SENSE2− | Differential current sense (−) input | Reference node for current comparator; supplies bias current above INTVCC − 0.5V to enable sensing. |
| TG1, TG2 | Top N-MOSFET gate driver output | Floating driver with INTVCC-referenced swing; drives bootstrap circuit for high-side FETs. |
| BG1, BG2 | Bottom N-MOSFET gate driver output | GND-referenced driver (0V to INTVCC); synchronously commutates low-side FETs. |
| VFB1, VFB2 | Feedback input (per channel) | Compares output voltage (via resistive divider) to 0.8V internal reference; ±5nA bias minimizes divider error. |
| ITH1, ITH2 | Error amplifier output / current limit control | Directly programs peak inductor current; gm = 2 mmho enables stable loop compensation. |
| SS1, SS2 | Soft-start and short-circuit timer | Internal 1μA pull-up ramps voltage for controlled startup; discharges at 9μA during fault to trigger latchoff at 1.5V. |
| PGOOD1 | Power-good indicator (open-drain) | Asserts low when VFB1 deviates >±10% from target; enables sequencing or system reset. |
| RUN1, RUN2 | Independent channel enable | Logic-level shutdown: <1.26V disables one channel; both <0.7V reduces IQ to 8μA globally. |
| PLLIN/MODE | Light-load mode select & sync input | Ground = Burst Mode®; INTVCC = forced continuous; 1.2V–(INTVCC−1.3V) = pulse-skipping; external clock = phase-lock. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Minimizes required output capacitance by enabling stable transient response across wide COUT/ESR ranges - reduces BOM count and board area. |
| Out-of-Phase Dual Control | 180° phase shift between channels cuts input RMS current by ~30%, allowing smaller input capacitors and lower EMI filter cost. |
| Adjustable Light-Load Operation | Selectable Burst Mode®, pulse-skipping, or forced continuous mode - preserves efficiency at microamp loads while maintaining low output ripple. |
| Integrated Short-Circuit Protection | Two independent latchoff timers (SS1/SS2) with arming threshold (2.0V) and latchoff threshold (1.5V) - prevents thermal runaway without external circuitry. |
| EXTVCC Switchover | Auto-switches INTVCC source from VIN LDO to EXTVCC LDO above 4.7V - enables efficient self-biasing from regulated output rails. |
Applications
| Portable Instrumentation | Notebook Power Management |
|---|---|
|
Use Scenario: High-precision handheld multimeter requiring dual isolated rails (3.3V logic + 8.5V analog) from single Li-ion battery. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller generating tightly regulated, low-noise outputs with minimal input ripple. Use Value: 170μA sleep IQ extends battery life; out-of-phase operation reduces input cap size by 40%; PGOOD1 enables safe power sequencing. |
Use Scenario: Embedded controller subsystem in ultrabook needing 3.3V core and 8.5V display backlight from 12V main rail. IC Role / Device Role / Timing Role: Dual-output step-down controller with independent soft-start and phase modulation to suppress audible noise. Use Value: OPTI-LOOP® simplifies compensation across varying load conditions; 99.4% duty cycle maintains regulation as battery discharges. |
| Distributed DC Power Systems | Battery-Operated Digital Devices |
|
Use Scenario: Industrial IoT gateway with separate 3.3V MCU and 8.5V RF module rails powered from 24V PoE-derived supply. IC Role / Device Role / Timing Role: Dual-channel controller supporting remote sensing, current monitoring, and coordinated fault response. Use Value: RSENSE/DCR flexibility accommodates high-current RF stage; latchoff protection isolates faults without system reset. |
Use Scenario: Wearable health monitor using single-cell Li-Po (3.0–4.2V) to generate stable 3.3V and 8.5V (for OLED bias) under dynamic load. IC Role / Device Role / Timing Role: Low-IQ dual controller enabling burst-mode operation during sensor idle periods. Use Value: 8μA shutdown IQ preserves standby time; adjustable soft-start prevents inrush into large capacitive loads. |
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 |
|---|---|---|---|
| LTC3868EUFD-1#PBF | Same silicon, –40°C to 85°C industrial grade but specified only over 0°C to 85°C; identical electrical specs and pinout. | Suitable for commercial environments where extended low-temp operation is not required. | Select when full –40°C qualification is unnecessary and cost sensitivity favors E-grade. |
| MP8765GL-Z | Monolithic dual buck (integrated MOSFETs); 4.5V–28V input; fixed 300kHz–2.2MHz fSW; no DCR sensing or phase modulation. | Better for space-constrained designs where efficiency >90% at mid-load suffices and discrete FETs are undesirable. | Choose for simplified layout and reduced external component count where programmability and ultra-low IQ are secondary. |
Compared with LTC3868IUFD-1#PBF, the LTC3868EUFD-1#PBF offers identical functionality at lower qualification cost, while the MP8765GL-Z trades configurability and 170μA IQ for monolithic integration and higher maximum switching frequency - making it suitable for compact, medium-efficiency applications without stringent low-power requirements.
Availability
LTC3868IUFD-1#PBF is available at Aetrix Electronics and suitable for portable instrumentation, notebook computing, and distributed DC power systems requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature operation.
Supply support for LTC3868IUFD-1#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 acquired Linear Technology in 2017 and maintains full product support, datasheets, and design resources for all Linear-branded power ICs including the LTC3868 family.
The LTC3868-1 series was designed specifically for high-efficiency, low-quiescent-current dual-output DC/DC conversion in battery-powered and thermally constrained systems - emphasizing precision regulation, flexible light-load behavior, and robust fault protection.
FAQ
What is the operating temperature range for the LTC3868IUFD-1#PBF?
The LTC3868IUFD-1#PBF is fully specified and guaranteed over the industrial temperature range of –40°C to +85°C. This is confirmed in the Absolute Maximum Ratings table and Order Information section of the official datasheet, where "I" grade denotes full industrial qualification - unlike the "E" grade which is only tested over 0°C to 85°C.
Does the LTC3868IUFD-1#PBF support DCR current sensing?
Yes, the LTC3868IUFD-1#PBF supports both RSENSE and DCR current sensing. The SENSE1+/SENSE1− and SENSE2+/SENSE2− pins accept differential inputs from either a discrete sense resistor or a copper trace/inductor DCR network, with programmable trip thresholds up to 57mV and bias current behavior defined in the Electrical Characteristics table.
How does the short-circuit latchoff function work on the LTC3868IUFD-1#PBF?
The LTC3868IUFD-1#PBF uses the SS1 and SS2 pins for independent short-circuit latchoff. Once the SS voltage exceeds 2.0V (arming threshold), a 9μA discharge current pulls it down if VFB drops below 70% of regulation. If SS falls below 1.5V, the channel latches off until VIN or RUN is recycled - a hardware-based protection that requires no external components.
Can the LTC3868IUFD-1#PBF operate with only one channel enabled?
Yes, the LTC3868IUFD-1#PBF supports independent channel control via RUN1 and RUN2. Driving RUN1 high and RUN2 low enables only Channel 1, reducing total quiescent current to 170μA in sleep mode. Both channels retain full functionality - including soft-start, current sensing, and protection - when operated singly or together.
What is the purpose of the PLLIN/MODE pin on the LTC3868IUFD-1#PBF?
The PLLIN/MODE pin on the LTC3868IUFD-1#PBF serves dual functions: as a synchronization input for phase-locking to an external clock (75kHz–850kHz), and as a light-load mode selector. Ground = Burst Mode®, INTVCC = forced continuous conduction, and 1.2V–(INTVCC−1.3V) = pulse-skipping - enabling optimized efficiency across the full load range.
LTC3868IUFD-1#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:
- 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#PBF FAQ
1.How can I place an order for LTC3868IUFD-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3868IUFD-1#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 LTC3868IUFD-1#PBF reliable?
The price and inventory of LTC3868IUFD-1#PBF 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#PBF is usually 5 days.
3.What payment methods are accepted for LTC3868IUFD-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3868IUFD-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3868IUFD-1#PBF?
LTC3868IUFD-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3868IUFD-1#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 LTC3868IUFD-1#PBF?
For technical support, including LTC3868IUFD-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3868IUFD-1#PBF requirements.
6.How does Aetrix verify that LTC3868IUFD-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3868IUFD-1#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 LTC3868IUFD-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC3868IUFD-1#PBF?
All LTC3868IUFD-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3868IUFD-1#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 LTC3868IUFD-1#PBF part is unused and in its original packaging.
Return procedure for LTC3868IUFD-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3868IUFD-1#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…
