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Analog Devices Inc. LTC3868EUH#TRPBF
- Part No.:
- LTC3868EUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3868EUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,470
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Product details
Overview
LTC3868EUH#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 for high-efficiency power conversion. It features 170µA no-load quiescent current, 0.8V reference accuracy (±1.5%), and supports 4V–24V input with dual outputs adjustable from 0.8V to 14V - ideal for battery-powered digital systems requiring tightly regulated 3.3V/8.5V rails.
For engineers reviewing the LTC3868EUH#TRPBF datasheet, LTC3868EUH#TRPBF pinout, LTC3868EUH#TRPBF application, or LTC3868EUH#TRPBF equivalent, key selection criteria include out-of-phase dual-channel operation for reduced input ripple, OPTI-LOOP® compensation for wide output capacitor ESR tolerance, and selectable light-load modes (Burst Mode®, pulse-skipping, forced continuous) to optimize efficiency across load range.
Technical Context
The LTC3868EUH#TRPBF implements a constant-frequency current-mode architecture with two independent control loops operating 180° out of phase, minimizing input capacitance requirements and supply-induced noise. Each channel uses an error amplifier (EA) with transconductance gm = 2 mmho and a precision 0.8V reference (±1.5% over temperature) to regulate output voltage via external resistor dividers.
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 drivers, supports RSENSE or DCR current sensing, and includes dedicated short-circuit latchoff (SS-based timeout), foldback current limiting, and 99.4% maximum duty cycle for ultra-low dropout operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 24V - supports wide intermediate bus voltages and multi-cell Li-ion, lead-acid, or 12V/24V industrial supplies. |
| Output Voltage Range | 0.8V to 14V per channel - enables generation of standard logic rails (1.2V, 1.8V, 3.3V, 5V, 8.5V) and custom bias supplies. |
| Quiescent Current | 170µA (one channel active) - extends battery life in portable instruments and always-on subsystems. |
| Switching Frequency | 75kHz to 850kHz (phase-lockable) or 50kHz to 900kHz (programmable) - balances size, efficiency, and EMI in space-constrained designs. |
| Reference Voltage Accuracy | ±1.5% over –40°C to 85°C - ensures stable regulation under thermal stress without external trimming. |
| Current Sense Threshold | 22–86mV (selectable via ILIM pin) - accommodates low-value sense resistors or DCR networks for minimal conduction loss. |
| Power Good Outputs | Two independent open-drain PGOOD1/PGOOD2 - provides precise ±10% output voltage monitoring with 25µs fault reporting delay. |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed thermal pad (Pin 33 = SGND), rated for –40°C to 85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1– / SENSE2– (Pins 1, 9) | Differential current sense (–) input | Supplies bias current when > INTVCC – 0.5V; enables accurate DCR/RSENSE sensing with common-mode rejection. |
| FREQ (Pin 2) | VCO frequency programming | 20µA internal pull-up sets switching frequency from 50kHz–900kHz via external resistor to GND. |
| PLLIN/MODE (Pin 5) | Sync input / light-load mode select | Accepts external clock (75–850kHz) for synchronization; selects Burst Mode®, pulse-skipping, or forced continuous operation. |
| RUN1 / RUN2 (Pins 7, 8) | Independent enable control | Logic-level shutdown: <1.26V disables one channel; both <0.7V reduces IQ to 8µA for full system sleep. |
| TG1/TG2 (Pins 26, 15) & BG1/BG2 (Pins 23, 18) | Top/bottom N-MOSFET gate drivers | High-current drivers (2.5Ω/1.5Ω TG; 2.4Ω/1.1Ω BG) with 25ns/16ns rise/fall times support fast-switching GaN/Si MOSFETs. |
| SS1/SS2 (Pins 29, 13) | 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. |
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. |
| OPTI-LOOP® compensation | Enables stable loop response across wide range of output capacitor values (10µF–1000µF) and ESR (0.5mΩ–100mΩ). |
| Programmable current limit threshold | Three levels (22/43/64mV) selected via ILIM pin - simplifies design for varying current-sense resistor or DCR values. |
| Short-circuit latchoff protection | SS-pin-based timeout circuit latches off output after ~100ms fault (with 100nF SS cap), preventing thermal runaway. |
| Low-dropout 99.4% duty cycle | Supports VIN-to-VOUT ratios as low as 1.01:1 - critical for high-efficiency buck conversion near input rail. |
Applications
| Portable Instrument Power Supply | Notebook System Rail Generator |
|---|---|
|
Use Scenario: Handheld multimeter or spectrum analyzer requiring isolated 3.3V logic and 8.5V analog rails from single Li-ion battery pack. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller generating two independent, tightly regulated outputs with coordinated soft-start and fault management. Use Value: 170µA quiescent current extends battery runtime; out-of-phase operation minimizes input capacitor size and PCB area. |
Use Scenario: Embedded controller in ultrabook managing core voltage (VCC_CORE) and I/O voltage (VCCIO) from 12V intermediate bus. IC Role / Device Role / Timing Role: High-efficiency dual-output controller delivering up to 5A @ 3.3V and 3.5A @ 8.5V with phase modulation to reduce EMI. Use Value: Phase-lockable frequency allows synchronization to system clock; PGOOD outputs enable safe sequencing with CPU and chipset. |
| Battery-Operated Digital Test Equipment | Distributed DC Power System |
|
Use Scenario: Portable oscilloscope with FPGA, ADC, and display subsystems needing clean, low-noise 1.2V, 1.8V, and 3.3V supplies. IC Role / Device Role / Timing Role: Dual-channel controller configured in parallel or cascaded topology to meet multi-rail sequencing and transient response demands. Use Value: OPTI-LOOP® compensation ensures stability with ceramic output caps; selectable light-load modes maintain >85% efficiency at 1mA load. |
Use Scenario: Industrial IoT gateway with multiple sensor nodes powered from centralized 24V DC bus. IC Role / Device Role / Timing Role: Dual-output controller powering local 3.3V microcontroller and 5V sensor interface rails with independent RUN control for dynamic power gating. Use Value: Wide 4V–24V input range accepts fluctuating bus voltage; EXTVCC pin enables efficient self-bias from secondary output. |
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 (Monolithic Power) | Integrated power stage (MOSFETs + controller); fixed 600kHz freq; no phase-lock capability; lower max VIN (16V). | Suitable for compact, cost-sensitive designs where board space is constrained and input voltage ≤16V. | Select MP2918GL-Z when integrated FETs simplify layout and thermal design outweighs need for programmable frequency or 24V input. |
| ISL95836IRZ-T (Renesas) | Triple-phase capable; supports Intel VR12.5/VR13 protocols; requires external PMBus interface; higher IQ (350µA). | Targeted at CPU/GPU VRMs in computing platforms requiring dynamic VID control and telemetry. | Select ISL95836IRZ-T only for Intel-compatible VRM applications demanding protocol compliance and telemetry - not for general-purpose dual-rail conversion. |
Compared with MP2918GL-Z and ISL95836IRZ-T, the LTC3868EUH#TRPBF offers superior flexibility in input voltage range (4–24V), light-load efficiency (170µA IQ), and phase synchronization - making it optimal for non-standard, battery-backed, or noise-sensitive dual-rail systems where discrete MOSFET selection and layout control are prioritized.
Availability
LTC3868EUH#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, notebook power subsystems, and distributed DC power systems requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to 85°C.
Supply support for LTC3868EUH#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3868EUH#TRPBF belongs to Linear's high-efficiency DC/DC controller product line, designed specifically for demanding power conversion applications where low quiescent current, precise regulation, and robust fault protection are critical - especially in battery-operated and thermally constrained environments.
FAQ
What is the absolute maximum input voltage rating for the LTC3868EUH#TRPBF?
The LTC3868EUH#TRPBF has an absolute maximum input supply voltage (VIN) rating of 28V. Operation beyond this voltage risks permanent damage. The recommended operating range remains 4V to 24V per the datasheet specifications, ensuring reliable performance and thermal margin. Always observe the 28V limit during transient conditions such as load dump or hot-swap events.
Does the LTC3868EUH#TRPBF support synchronization to an external clock source?
Yes, the LTC3868EUH#TRPBF supports external clock synchronization via the PLLIN/MODE pin (Pin 5). When an external clock signal (75kHz–850kHz) is applied, the internal phase-locked loop aligns the rising edge of TG1 with the external clock's rising edge. This feature enables deterministic EMI reduction and coordinated switching across multiple controllers in complex power systems.
How does the LTC3868EUH#TRPBF achieve low quiescent current in battery-powered applications?
The LTC3868EUH#TRPBF achieves 170µA quiescent current (one channel active) through optimized biasing, sleep-mode architecture, and intelligent gate driver control. In Sleep Mode, internal circuits-including error amplifiers and oscillators-are selectively disabled while maintaining regulation. Shutdown reduces current to 8µA. These modes are activated via RUN1/RUN2 pins and do not compromise startup reliability or output accuracy.
Can the LTC3868EUH#TRPBF be used with DCR current sensing instead of a sense resistor?
Yes, the LTC3868EUH#TRPBF explicitly supports DCR current sensing. Its SENSE+ and SENSE– inputs accept differential signals from a series inductor's DCR network, with built-in offset compensation and programmable gain. The device's current comparator operates with matched input bias currents (±1µA), enabling accurate sensing across temperature without additional calibration components.
What protection features does the LTC3868EUH#TRPBF provide against output short circuits?
The LTC3868EUH#TRPBF provides dual-layer short-circuit protection: (1) foldback current limiting that progressively reduces peak current as output voltage drops below 72% of nominal, and (2) SS-pin-based latchoff that triggers after a user-defined timeout (e.g., ~100ms with 100nF capacitor). Both features operate independently per channel and prevent thermal failure without requiring external circuitry.
LTC3868EUH#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 32-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:
- Current Limit, Enable, Frequency Control, Phase Control, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC3868EUH#TRPBF FAQ
1.How can I place an order for LTC3868EUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3868EUH#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 LTC3868EUH#TRPBF reliable?
The price and inventory of LTC3868EUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3868EUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3868EUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3868EUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3868EUH#TRPBF?
LTC3868EUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3868EUH#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 LTC3868EUH#TRPBF?
For technical support, including LTC3868EUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3868EUH#TRPBF requirements.
6.How does Aetrix verify that LTC3868EUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3868EUH#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 LTC3868EUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3868EUH#TRPBF?
All LTC3868EUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3868EUH#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 LTC3868EUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC3868EUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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