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Analog Devices Inc. LTC3868EGN-1#PBF
- Part No.:
- LTC3868EGN-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3868EGN-1#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:147
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Product details
Overview
LTC3868EGN-1#PBF from Analog Devices (formerly Linear Technology) is a dual-phase, synchronous step-down DC/DC controller IC designed for high-efficiency intermediate bus conversion. It delivers two independent output rails (e.g., 8.5V/3.3V), supports 4V–24V input, 0.8V–14V output, and achieves 170μA quiescent current in single-channel sleep mode - ideal for battery-powered portable instruments and notebook computers.
For engineers reviewing the LTC3868EGN-1#PBF datasheet, LTC3868EGN-1#PBF pinout, LTC3868EGN-1#PBF application, or LTC3868EGN-1#PBF equivalent, key selection criteria include out-of-phase dual-channel operation to reduce input ripple, OPTI-LOOP® compensation for wide capacitor ESR tolerance, selectable light-load modes (Burst Mode®, pulse-skipping, forced continuous), and robust short-circuit latchoff with adjustable soft-start.
Technical Context
The LTC3868EGN-1#PBF implements a constant-frequency current-mode architecture with two 180° out-of-phase controllers, enabling reduced input capacitance and lower EMI. Its dual independent error amplifiers drive ITH pins to set per-channel peak current limits, while the 0.8V precision reference and ±10% PGOOD1 threshold ensure tight regulation across load and line variations.
It integrates dual gate drivers (TG/BG) with 2.5Ω pull-up/1.5Ω pull-down on top-side and 2.4Ω/1.1Ω on bottom-side MOSFETs, supports RSENSE or DCR current sensing, and features an internal 5.1V LDO (INTVCC) powered either from VIN or an external 4.7–14V EXTVCC supply - eliminating need for auxiliary bias rails.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 24V - accommodates 5V/12V intermediate buses and Li-ion/Li-poly battery stacks without pre-regulation. |
| Output Voltage Range | 0.8V to 14V - supports core logic, I/O, and analog rails via external resistor dividers on VFB1/VFB2. |
| Quiescent Current (1 ch active) | 170μA typical in sleep mode - extends runtime in always-on portable instrumentation. |
| Switching Frequency | 75kHz to 850kHz phase-lockable, or 50kHz–900kHz programmable - enables optimization of size vs. efficiency in space-constrained designs. |
| Current Sense Threshold | 43–57mV max at VFB = 0.7V - allows accurate current limiting with low-value sense resistors or DCR networks. |
| Power Good Output | PGOOD1 open-drain with ±10% trip hysteresis - provides reliable system power sequencing and fault indication. |
| Shutdown Current | 8μA typical - ensures minimal battery drain during full system standby. |
Pinout & Package
Package: 28-Lead Plastic SSOP (narrow), RoHS-compliant, operating temperature range –40°C to +85°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+, SENSE2+ | Differential current sense (+) inputs | Connect to high-side of RSENSE or DCR network; sets per-channel current limit with ITH voltage. |
| SENSE1–, SENSE2– | Differential current sense (–) inputs | Return path for sense signal; supplies bias current above INTVCC – 0.5V to enable comparator operation. |
| TG1, TG2 | Top N-MOSFET gate drivers | Floating outputs with ~INTVCC swing over SW node; require bootstrap capacitors between BOOST and SW. |
| BG1, BG2 | Bottom N-MOSFET gate drivers | Ground-referenced drivers (0V to INTVCC); connect directly to synchronous rectifier sources. |
| VFB1, VFB2 | Feedback inputs | Monitor regulated output via external resistor divider; referenced to precise 0.8V internal bandgap. |
| SS1, SS2 | Soft-start / latchoff timer inputs | Capacitor-to-ground sets ramp time; also discharges during short-circuit to trigger latchoff below 1.5V. |
| RUN1, RUN2 | Independent channel enable inputs | Logic-level control: <1.26V disables channel; both <0.7V enters ultra-low-IQ shutdown (8μA). |
| PGOOD1 | Power-good status output | Open-drain flag pulled low when VFB1 deviates >±10% from target - used for sequencing or fault reporting. |
Key Features
| Feature | Design Value |
|---|---|
| Out-of-phase dual controllers | Reduces RMS input ripple current by ~30%, allowing smaller input bulk capacitors and lower EMI filtering cost. |
| OPTI-LOOP® compensation | Enables stable loop response across wide range of output capacitor values and ESR - simplifies design across multiple board revisions. |
| Selectably optimized light-load operation | Three modes (Burst Mode®, pulse-skipping, forced continuous) let designers trade off efficiency vs. output ripple/noise per application need. |
| Short-circuit latchoff with arming delay | SS pin doubles as soft-start timer and fault timeout; latches off only after voltage drops below 1.5V post-arming (>2V), preventing nuisance trips. |
| Internal 5.1V LDO with EXTVCC switchover | Eliminates need for external bias supply; automatically switches to efficient EXTVCC source if >4.7V present - improves overall system efficiency. |
Applications
| Portable Instrument Power | Notebook System Rail Generation |
|---|---|
|
Use Scenario: Handheld multimeters and portable oscilloscopes requiring isolated, low-noise dual-rail supplies from single-cell Li-ion batteries. IC Role / Device Role / Timing Role: Dual-phase controller generating 3.3V logic rail and 8.5V analog front-end rail with out-of-phase switching to minimize input ripple. Use Value: 170μA sleep IQ extends battery life; PGOOD1 enables clean power sequencing; latchoff protects against probe shorts. |
Use Scenario: Mainboard VRM supplying CPU core (VDD) and I/O (VDDIO) rails in ultraportable notebooks. IC Role / Device Role / Timing Role: High-efficiency dual-controller managing two independent buck stages with shared thermal footprint and synchronized frequency. Use Value: Phase interleaving reduces input cap size; OPTI-LOOP® tolerates aging electrolytics; EXTVCC option powers INTVCC from 5V rail for higher efficiency. |
| Battery-Operated Digital Devices | Distributed DC Power Systems |
|
Use Scenario: Wireless sensor nodes powered by 2S Li-ion packs needing regulated 1.8V and 3.3V rails with minimal standby drain. IC Role / Device Role / Timing Role: Low-IQ dual controller delivering tightly regulated outputs while supporting deep-sleep wake-up via RUN pin control. Use Value: 8μA shutdown current preserves battery during months of dormancy; adjustable soft-start prevents inrush into large hold-up caps. |
Use Scenario: Industrial IoT gateway with distributed 12V/5V/3.3V rails derived from 24V PoE or DC bus. IC Role / Device Role / Timing Role: Intermediate bus converter stepping 24V down to 5V/3.3V with high PSRR and fast transient response for noise-sensitive peripherals. Use Value: Wide 4–24V input handles bus transients; 99% duty cycle supports near-dropout operation; RSENSE/DCR flexibility eases layout in multi-board systems. |
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 die, 28-pin 4mm × 5mm QFN package with exposed thermal pad; θJA = 43°C/W vs. 90°C/W for SSOP. | Better thermal performance in compact layouts; requires reflow-compatible PCB land pattern and solder paste stencil. | Choose for higher power density or elevated ambient temperature environments where thermal resistance matters. |
| MP2918GL-Z | Monolithic dual-phase controller (integrated MOSFETs); 4.5–18V input; fixed 0.6V ref; no EXTVCC or latchoff timer. | Lower BOM count but limited to ≤30A total; lacks independent soft-start and short-circuit latchoff functionality. | Choose for cost-sensitive, medium-current applications where discrete FETs are undesirable and latchoff is not required. |
Compared with LTC3868EGN-1#PBF, the QFN variant offers superior thermal dissipation for sustained high-current operation, while the MP2918GL-Z trades configurability and protection features for integration and lower component count - making it suitable only where its fixed parameters and missing safety functions align with system requirements.
Availability
LTC3868EGN-1#PBF is available at Aetrix Electronics and suitable for portable instrumentation, notebook computing, battery-operated digital devices requiring stable component supply with long-term industrial lifecycle support.
Supply support for LTC3868EGN-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, documentation, and manufacturing continuity for all Linear-branded power management ICs.
The LTC3868-1 family was engineered for high-efficiency, low-quiescent-current dual-output DC/DC conversion in space- and battery-constrained systems - emphasizing precision regulation, flexible light-load behavior, and robust fault protection.
FAQ
What is the maximum duty cycle supported by the LTC3868EGN-1#PBF?
The LTC3868EGN-1#PBF supports up to 99.4% maximum duty cycle in dropout conditions, enabling operation with very small input-to-output voltage differentials - critical for maintaining regulation when input voltage sags near the output level in battery-powered systems using the LTC3868EGN-1#PBF.
How does the LTC3868EGN-1#PBF implement short-circuit protection?
The LTC3868EGN-1#PBF uses a dual-stage short-circuit response: first, foldback current limiting reduces peak inductor current proportionally as output voltage drops below 70%; second, once the SS pin voltage falls below 1.5V after arming above 2V, the controller latches off - a behavior confirmed in the LTC3868EGN-1#PBF datasheet Figure 1 and Section "Short-Circuit Latchoff".
Can the LTC3868EGN-1#PBF operate with only one channel enabled?
Yes - the LTC3868EGN-1#PBF supports independent channel control via RUN1 and RUN2 pins. Pulling RUN2 low while holding RUN1 high enables only Channel 1, reducing total quiescent current to 170μA in sleep mode, as specified in the Electrical Characteristics table under "Sleep Mode (One Channel On)" for the LTC3868EGN-1#PBF.
What is the purpose of the PLLIN/MODE pin on the LTC3868EGN-1#PBF?
The PLLIN/MODE pin on the LTC3868EGN-1#PBF serves two roles: (1) as a synchronization input for phase-locking to an external clock (75–850kHz), and (2) as a light-load mode selector - grounded for Burst Mode®, tied to INTVCC for forced continuous conduction, or biased to 1.2–(INTVCC−1.3)V for pulse-skipping - all explicitly defined in the LTC3868EGN-1#PBF Pin Functions section.
Does the LTC3868EGN-1#PBF require external components for gate driving?
Yes - the LTC3868EGN-1#PBF drives external N-channel MOSFETs and requires external bootstrap capacitors between BOOST and SW pins for high-side gate drive, Schottky diodes from BOOST to INTVCC, and gate resistors for damping. No integrated drivers are present; this discrete-FET architecture is fundamental to the LTC3868EGN-1#PBF's high-voltage, high-efficiency design.
LTC3868EGN-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm Width)
- 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-SSOP
LTC3868EGN-1#PBF FAQ
1.How can I place an order for LTC3868EGN-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3868EGN-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 LTC3868EGN-1#PBF reliable?
The price and inventory of LTC3868EGN-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 LTC3868EGN-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC3868EGN-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3868EGN-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3868EGN-1#PBF?
LTC3868EGN-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3868EGN-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 LTC3868EGN-1#PBF?
For technical support, including LTC3868EGN-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3868EGN-1#PBF requirements.
6.How does Aetrix verify that LTC3868EGN-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3868EGN-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 LTC3868EGN-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC3868EGN-1#PBF?
All LTC3868EGN-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3868EGN-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 LTC3868EGN-1#PBF part is unused and in its original packaging.
Return procedure for LTC3868EGN-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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