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Analog Devices Inc. LTC3868EGN-1#TRPBF
- Part No.:
- LTC3868EGN-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3868EGN-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,849
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Product details
Overview
LTC3868EGN-1#TRPBF 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 RSENSE or DCR current sensing, operates from 4V–24V input, regulates outputs from 0.8V to 14V, and achieves 170μA quiescent current in single-channel sleep mode - ideal for battery-powered portable instruments and notebook computing power subsystems.
For engineers reviewing the LTC3868EGN-1#TRPBF datasheet, LTC3868EGN-1#TRPBF pinout, LTC3868EGN-1#TRPBF application, or LTC3868EGN-1#TRPBF equivalent, key selection criteria include out-of-phase dual-channel operation for reduced input ripple, OPTI-LOOP® compensation flexibility, programmable 50kHz–900kHz switching frequency, selectable light-load modes (Burst Mode®, pulse-skipping, forced continuous), and robust short-circuit protection with latchoff and foldback.
Technical Context
The LTC3868EGN-1#TRPBF implements a constant-frequency current-mode architecture with two independent 180° out-of-phase controllers, each driving external N-channel MOSFETs. Its dual-channel phase offset minimizes input capacitor RMS current and system-level conducted noise. The internal error amplifier drives ITH pins to set per-channel peak current thresholds, while VFB pins monitor regulated output voltage against a precision 0.8V reference.
It integrates dual gate drivers (TG/BG) with 2.5Ω pull-up and 1.5Ω pull-down on TG, 2.4Ω/1.1Ω on BG, and supports bootstrapped top-side drive via BOOST pins. Power sequencing is managed via independent RUN1/RUN2 shutdown controls and SS1/SS2 soft-start/latchoff timers, with PGOOD1 monitoring only Channel 1 output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 24V - supports wide-range intermediate bus and multi-cell Li-ion battery inputs. |
| Output Voltage Range | 0.8V to 14V - enables generation of core, I/O, and auxiliary rails with external resistor dividers. |
| Quiescent Current (1 ch active) | 170μA typical - extends runtime in always-on portable systems without compromising regulation. |
| Switching Frequency | 50kHz to 900kHz programmable - allows optimization of size (high-freq) vs. efficiency (mid-freq) and EMI filtering. |
| Current Sense Method | RSENSE or DCR - supports low-loss inductor-based sensing or precision shunt-based current measurement. |
| Protection Features | Output overvoltage, short-circuit latchoff, foldback current limiting, and 99% max duty cycle - ensures safe operation under fault conditions and dropout. |
| Reference Voltage Accuracy | ±1.5% over temperature - guarantees tight output regulation across industrial ambient range (–40°C to 85°C). |
Pinout & Package
Package: 28-Lead Plastic SSOP (narrow), RoHS-compliant, operating temperature range –40°C to +85°C. Exposed pad not present (unlike QFN variant); thermal resistance θJA = 90°C/W.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+, SENSE2+ | Differential current sense (+) input | Connects to high-side of current-sense resistor or DCR network; sets channel-specific current limit threshold with SENSE–. |
| SENSE1–, SENSE2– | Differential current sense (–) input | References current comparator; supplies bias current when > INTVCC – 0.5V - critical for accurate DCR sensing. |
| VFB1, VFB2 | Feedback voltage input | Monitors output divider ratio; regulates to 0.8V reference - determines final output voltage with ±1.5% accuracy. |
| ITH1, ITH2 | Error amplifier output / current limit control | Directly programs peak inductor current; voltage range 0.425V–2V maps to full-scale current limit adjustment. |
| RUN1, RUN2 | Digital enable/disable control | Logic-level shutdown: <1.26V disables individual channel; both <0.7V forces global shutdown (8μA IQ). |
| SS1, SS2 | Soft-start / short-circuit timer | Internal 1μA pull-up charges external capacitor for controlled ramp; also discharges at 9μA during fault to trigger latchoff at 1.5V. |
| TG1, TG2 | Top N-MOSFET gate driver output | Floating driver with ~2.5Ω pull-up; swings from SW node + (INTVCC – 0.5V) - requires bootstrap capacitor and Schottky diode. |
| BG1, BG2 | Bottom N-MOSFET gate driver output | Ground-referenced driver with ~1.1Ω pull-down; drives synchronous rectifier with fast 13ns fall time (CLOAD = 3300pF). |
| PGOOD1 | Power-good indicator (open-drain) | Asserts low when VFB1 deviates >±10% from target - provides system-level rail monitoring for Channel 1 only. |
| PLLIN/MODE | Sync input / light-load mode select | Accepts external clock (75–850kHz) or DC voltage: GND = Burst Mode®, INTVCC = forced continuous, 1.2–3.8V = pulse-skipping. |
| FREQ | Frequency programming pin | 20μA internal current source develops voltage across external resistor to set 50–900kHz oscillator frequency. |
| INTVCC | Internal LDO output (5.1V) | Powers gate drivers and control logic; sourced from VIN or EXTVCC (≥4.7V) - improves efficiency when powered from local rail. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Enables stable loop response across wide range of output capacitance (10μF–1000μF) and ESR (0.5mΩ–100mΩ), reducing design iterations. |
| Out-of-Phase Dual Control | 180° phase shift between channels halves input ripple current, allowing smaller, lower-cost input capacitors and reduced EMI filtering burden. |
| Low-IQ Sleep Mode | 170μA (one channel active) or 300μA (both active) - preserves battery life in standby without sacrificing fast wake-up capability. |
| Programmable Light-Load Operation | Selectable Burst Mode®, pulse-skipping, or forced continuous mode via single PLLIN/MODE pin - balances efficiency vs. output ripple per application need. |
| Robust Short-Circuit Protection | Independent SS-based latchoff (1.5V threshold) + foldback current limiting - prevents thermal runaway and enables safe auto-recovery after fault clearance. |
| Wide VIN and VOUT Flexibility | 4V–24V input and 0.8V–14V output ranges support diverse architectures including 12V/24V intermediate buses and sub-1V core supplies. |
Applications
| Portable Medical Instrumentation | Notebook Computer Power Subsystem |
|---|---|
Use Scenario: Handheld ultrasound or glucose meter requiring dual isolated rails (e.g., 3.3V logic + 8.5V analog front-end) from single Li-ion battery. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing independent voltage domains with precise sequencing and low-noise operation. Use Value: 170μA sleep IQ extends battery life; out-of-phase operation minimizes input ripple-induced sensor noise; PGOOD1 confirms stable analog supply before data acquisition. |
Use Scenario: Mainboard VRM delivering CPU core (0.8–1.2V) and chipset I/O (3.3V/5V) rails from 12V or 19V adapter input. IC Role / Device Role / Timing Role: High-current, dual-output step-down controller supporting dynamic load transients and strict voltage tolerance requirements. Use Value: OPTI-LOOP® ensures stability with ceramic output caps; adjustable soft-start prevents inrush into large bulk capacitance; latchoff protects against connector shorts during hot-plug events. |
| Distributed DC Power Systems | Battery-Powered Test Equipment |
Use Scenario: Rack-mounted modular instrument with multiple plug-in cards needing localized 5V and 3.3V supplies derived from 24V backplane. IC Role / Device Role / Timing Role: Intermediate bus converter providing tightly regulated, low-noise secondary rails with minimal board space. Use Value: 28-lead SSOP package fits dense layouts; 4V–24V input accommodates aging battery or variable bus voltage; phase-lockable frequency enables synchronized switching across modules to reduce system-level EMI. |
Use Scenario: Portable oscilloscope or spectrum analyzer drawing power from removable LiPo pack, requiring clean 3.3V digital and 12V analog supplies. IC Role / Device Role / Timing Role: Dual-output controller enabling efficient conversion with minimal heat dissipation in sealed enclosure. Use Value: RSENSE/DCR flexibility allows optimal trade-off between sensing loss and PCB area; 99% duty cycle supports deep dropout during battery sag; EXTVCC option powers INTVCC from local 5V rail to improve overall efficiency. |
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#TRPBF | Same die, 28-lead 4mm × 5mm QFN package with exposed thermal pad (θJA = 43°C/W vs. 90°C/W); includes clock-out and phase modulation features. | Preferred for thermally constrained designs requiring higher power density and enhanced synchronization capability. | Select when PCB layout supports QFN thermal vias and system demands tighter frequency coordination across multiple converters. |
| MP2918GL-Z | Monolithic dual buck (integrated MOSFETs), 4.5V–18V input, fixed 0.6V ref, no DCR sensing, lower IQ (120μA), no PGOOD latchoff. | Suitable for cost-sensitive, medium-power applications where integration reduces BOM count but limits voltage/frequency flexibility. | Choose for simpler, lower-component-count designs below 10A per channel where external FET control and advanced protection are not required. |
Compared with LTC3868EGN-1#TRPBF, the QFN variant offers superior thermal performance and extra sync features at the cost of larger footprint and stricter layout rules, while the MP2918GL-Z trades configurability and protection depth for integration and lower quiescent current - making each suitable for distinct power architecture priorities.
Availability
LTC3868EGN-1#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, notebook computing, and distributed DC power systems requiring stable component supply, long-term manufacturability, and guaranteed industrial temperature operation.
Supply support for LTC3868EGN-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 qualification and long-term product support.
The LTC3868-1 series is part of Linear's precision current-mode controller family, engineered for demanding dual-rail DC/DC conversion in battery-powered and noise-sensitive applications where efficiency, reliability, and design flexibility are critical.
FAQ
What is the maximum supported switching frequency for LTC3868EGN-1#TRPBF?
The LTC3868EGN-1#TRPBF supports a programmable switching frequency from 50kHz to 900kHz using an external resistor on the FREQ pin. When synchronized to an external clock via PLLIN/MODE, it operates from 75kHz to 850kHz. The upper limit is determined by minimum on-time (95ns) and practical layout constraints - exceeding 900kHz risks instability or reduced duty-cycle range.
Does LTC3868EGN-1#TRPBF support DCR current sensing on both channels?
Yes, LTC3868EGN-1#TRPBF fully supports DCR current sensing on both channels via dedicated SENSE1+/SENSE1– and SENSE2+/SENSE2– pins. The internal current comparators accommodate the common-mode voltage range (up to 16V) and bias current behavior required for accurate DCR-based sensing, as confirmed in the Electrical Characteristics table and Pin Functions section.
How does the short-circuit latchoff function work on LTC3868EGN-1#TRPBF?
LTC3868EGN-1#TRPBF implements independent short-circuit latchoff per channel using the SS1/SS2 pins. Once the SS voltage exceeds 2V (arming threshold), a 9μA discharge current pulls SS down during output faults. If SS falls below 1.5V, the controller latches off until VIN or RUN is cycled. This mechanism is validated in the Applications Information and Typical Performance Characteristics (Figure G27).
Can LTC3868EGN-1#TRPBF operate with only one channel enabled?
Yes, LTC3868EGN-1#TRPBF supports independent channel control: pulling RUN1 low disables Channel 1 while Channel 2 remains fully operational, and vice versa. Quiescent current drops to 170μA in this asymmetric sleep mode - a key specification verified in the Electrical Characteristics table under "Sleep Mode (One Channel On)".
What is the purpose of the EXTVCC pin on LTC3868EGN-1#TRPBF?
The EXTVCC pin on LTC3868EGN-1#TRPBF allows powering the internal 5.1V INTVCC LDO from an external supply (≥4.7V), bypassing the VIN-based regulator. This improves overall system efficiency when a clean, locally generated rail (e.g., from another LTC3868-1 output) is available - a feature explicitly detailed in the Pin Functions and Operation sections.
LTC3868EGN-1#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm Width)
- 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-SSOP
LTC3868EGN-1#TRPBF FAQ
1.How can I place an order for LTC3868EGN-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3868EGN-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 LTC3868EGN-1#TRPBF reliable?
The price and inventory of LTC3868EGN-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 LTC3868EGN-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3868EGN-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3868EGN-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3868EGN-1#TRPBF?
LTC3868EGN-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3868EGN-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 LTC3868EGN-1#TRPBF?
For technical support, including LTC3868EGN-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3868EGN-1#TRPBF requirements.
6.How does Aetrix verify that LTC3868EGN-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3868EGN-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 LTC3868EGN-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3868EGN-1#TRPBF?
All LTC3868EGN-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3868EGN-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 LTC3868EGN-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC3868EGN-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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