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Analog Devices Inc. LTC3868EUFD-1#TRPBF
- Part No.:
- LTC3868EUFD-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3868EUFD-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,036
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Product details
Overview
LTC3868EUFD-1#TRPBF from Analog Devices (formerly Linear Technology) is a dual-phase, synchronous step-down DC/DC controller IC designed for high-efficiency, low-quiescent-current power conversion in battery-powered and intermediate-bus systems. It delivers two independent output voltages (e.g., 3.3V/5A and 8.5V/3.5A), supports 4V–24V input, features 170μA no-load IQ per active channel, and operates out-of-phase to reduce input ripple and EMI. It is used in notebook computers and portable instrumentation where thermal efficiency and light-load performance are critical.
For engineers reviewing the LTC3868EUFD-1#TRPBF datasheet, LTC3868EUFD-1#TRPBF pinout, LTC3868EUFD-1#TRPBF application, or LTC3868EUFD-1#TRPBF equivalent, key selection criteria include its dual-channel current-mode architecture, 0.8V reference accuracy, OPTI-LOOP® compensation, programmable 50kHz–900kHz switching frequency, and support for RSENSE or DCR current sensing - all implemented in a thermally enhanced 28-pin 4mm × 5mm QFN package.
Technical Context
The LTC3868EUFD-1#TRPBF employs a constant-frequency current-mode control architecture with two independent controllers operating 180° out of phase to minimize input capacitor RMS current and system noise. Each channel integrates transconductance error amplifiers (gm = 2 mmho), precision 0.8V ±1.5% feedback references, and dedicated ITH pins for loop compensation and current limit programming.
Its dual-gate-drive architecture supports all-N-channel MOSFET topologies with integrated 2.5Ω pull-up / 1.5Ω pull-down TG drivers and 2.4Ω / 1.1Ω BG drivers. The device includes independent RUN/SS pins per channel, a shared PLLIN/MODE pin for light-load mode selection (Burst Mode®, pulse-skipping, or forced continuous), and dual PGOOD monitoring with ±10% trip hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 24V - supports wide-range intermediate bus rails and multi-cell Li-ion, Li-polymer, or lead-acid battery inputs. |
| Output Voltage Range | 0.8V to 14V - enables generation of standard logic rails (1.2V, 1.8V, 3.3V, 5V, 8.5V, 12V) with ±1.5% regulation accuracy at VFB. |
| No-Load Quiescent Current | 170μA (one channel active) - extends runtime in always-on, battery-backed subsystems such as real-time clocks or sensor wake-up circuits. |
| Switching Frequency Range | 50kHz to 900kHz (programmable) - allows optimization of size (higher fSW → smaller inductors/caps) vs. efficiency (lower fSW → lower switching loss). |
| Current Sensing | RSENSE or DCR - enables flexible, low-loss current monitoring without added resistive power loss or external op-amps. |
| Protection Features | Output overvoltage lockout (±13%), short-circuit latchoff, foldback current limiting, and 99.4% max duty cycle - ensures robust operation under fault conditions and dropout. |
| Package & Thermal | 28-pin 4mm × 5mm QFN with exposed pad (θJA = 43°C/W) - provides low thermal resistance for high-current dual-phase designs without heatsinks. |
Pinout & Package
Package: 28-lead plastic QFN (4mm × 5mm), exposed thermal pad (Pin 29) tied to SGND. Requires soldering of exposed pad for rated thermal performance (TJMAX = 125°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+, SENSE2+ | Differential current sense (+) inputs | Connect to DCR network or current-sense resistor high side; sets peak current threshold with SENSE– and ITH voltage. |
| SENSE1–, SENSE2– | Differential current sense (–) inputs | Reference node for current comparator; supplies bias current above INTVCC – 0.5V to enable accurate high-side sensing. |
| TG1, TG2 | Top N-MOSFET gate drivers | Floating drivers with ~2.5Ω pull-up / 1.5Ω pull-down; swing = INTVCC – 0.5V superimposed on SW node voltage. |
| BG1, BG2 | Bottom N-MOSFET gate drivers | Ground-referenced drivers with ~2.4Ω pull-up / 1.1Ω pull-down; swing = 0V to INTVCC. |
| SW1, SW2 | Switch node connections | Direct connection to inductor and external bootstrap diode/capacitor; must be routed with low-inductance layout. |
| BOOST1, BOOST2 | Bootstrap supply inputs | Provide floating bias for TG drivers; voltage swing = INTVCC to (VIN + INTVCC); require Schottky diode + ceramic cap. |
| VFB1, VFB2 | Feedback voltage inputs | Monitor regulated output via resistor divider; internal 0.8V reference enables precise output setting (±1.5% over temp). |
| ITH1, ITH2 | Error amplifier outputs | Set current limit threshold and provide loop compensation node; voltage directly controls peak inductor current. |
| SS1, SS2 | Soft-start / latchoff timer inputs | Internal 1μA pull-up charges external capacitor for controlled ramp; also discharges at 9μA during short-circuit to trigger latchoff. |
| PGOOD1 | Power-good open-drain output | Asserts low when VFB1 deviates >±10% from setpoint; requires external pull-up; no PGOOD2 on -1 version. |
| RUN1, RUN2 | Independent channel enable inputs | Logic-level shutdown: <1.26V disables one channel; both <0.7V enables 8μA shutdown mode. |
| PLLIN/MODE | Sync input / light-load mode select | Accepts external clock (75–850kHz) or DC voltage: GND = Burst Mode®, INTVCC = forced CCM, 1.2–3.8V = pulse-skipping. |
| FREQ | Frequency programming pin | 20μA internal current source develops voltage across external resistor to set 50–900kHz fixed frequency. |
| VIN, PGND, SGND | Main input, power ground, signal ground | VIN powers internal LDO; PGND connects to bottom FET sources; SGND is separate analog ground for feedback/sense paths. |
| INTVCC, EXTVCC | Internal LDO output / external bias input | INTVCC = 5.1V ±1.1% output powering drivers/control logic; EXTVCC >4.7V bypasses VIN LDO for higher efficiency. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Enables stable transient response across wide range of output capacitance (10μF–1000μF) and ESR (1mΩ–100mΩ) without loop re-tuning. |
| Out-of-Phase Dual Control | Reduces input ripple current by up to 70% vs. in-phase operation, allowing smaller input bulk capacitors and lower EMI filter cost. |
| Low-IQ Sleep Mode | 170μA quiescent current with one channel active enables >100-hour standby in portable devices powered by 2000mAh Li-ion cells. |
| Programmable Light-Load Operation | Selectable Burst Mode®, pulse-skipping, or forced continuous conduction optimizes efficiency across 10μA–5A load range without external circuitry. |
| Short-Circuit Latchoff Protection | Independent SS-based timeout per channel prevents thermal runaway during sustained overload; latchoff delay programmable via CSS value. |
| 99.4% Max Duty Cycle | Supports ultra-low dropout operation (e.g., 12V→11.8V) with minimal voltage headroom, critical for post-regulation in high-VIN systems. |
Applications
| Notebook Power Management | Portable Test Instrumentation |
|---|---|
Use Scenario: Dual-rail power for CPU core (1.2V/3A) and I/O (3.3V/2A) in ultrabook platforms with strict thermal envelope and battery life targets. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing independent voltage domains with coordinated soft-start and PGOOD sequencing. Use Value: 170μA sleep IQ extends battery runtime by >15% vs. legacy controllers; out-of-phase operation reduces input cap count by 2× while maintaining <10mV ripple. | Use Scenario: Powering mixed-signal front-end (2.5V ADC reference, 5V analog stage, 1.8V FPGA core) in handheld oscilloscopes and multimeters. IC Role / Device Role / Timing Role: Precision dual-output controller delivering tightly regulated, low-noise rails with independent enable and fault reporting per channel. Use Value: 0.8V ±1.5% reference and OPTI-LOOP® ensure <±10mV output deviation under dynamic load steps; Burst Mode® maintains >85% efficiency at 100μA loads. |
| Battery-Powered Digital Systems | Distributed DC Power Architectures |
Use Scenario: Powering ARM Cortex-M based edge nodes (3.3V MCU, 1.2V RF SoC, 5V USB interface) running on 3S Li-ion packs (9–12.6V). IC Role / Device Role / Timing Role: High-efficiency dual buck controller supporting wide VIN range and seamless transition between battery and adapter input. Use Value: 4V–24V input range accommodates full battery discharge curve; 8μA shutdown IQ eliminates parasitic drain during storage. | Use Scenario: Intermediate bus converter in industrial IoT gateway, generating 5V/3A and 12V/2A from 24V backplane for isolated downstream modules. IC Role / Device Role / Timing Role: Dual-phase controller driving discrete MOSFETs to deliver scalable, thermally balanced power with phase synchronization capability. Use Value: PLLIN input enables synchronization to system master clock, eliminating beat frequencies; 99.4% duty cycle supports 24V→23.5V post-regulation with minimal loss. |
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 | Single-chip dual-phase controller with integrated MOSFET drivers only; no RSENSE/DCR flexibility; fixed 600kHz fSW; lacks PGOOD1 and latchoff protection. | Suitable for cost-sensitive, space-constrained consumer applications where discrete FETs are not required and fault coverage is less critical. | Select MP2918GL-Z only if board area and BOM count are prioritized over design flexibility, protection robustness, and light-load efficiency tuning. |
| LTC3855IUFD#TRPBF | Single-phase controller with identical 0.8V reference, OPTI-LOOP®, and Burst Mode®; lacks second channel, phase sync, and dual PGOOD; same QFN package footprint. | Applicable when only one regulated rail is needed or when dual rails are implemented using two separate controllers for redundancy or isolation. | Choose LTC3855IUFD#TRPBF for single-rail designs requiring identical feature set and layout compatibility, but not for true dual-phase interleaving. |
Compared with MP2918GL-Z and LTC3855IUFD#TRPBF, the LTC3868EUFD-1#TRPBF uniquely combines dual-channel independence, comprehensive fault protection (latchoff + foldback), RSENSE/DCR sensing choice, and programmable light-load modes - making it optimal for high-reliability, battery-sensitive, and thermally constrained dual-rail systems.
Availability
LTC3868EUFD-1#TRPBF is available at Aetrix Electronics and suitable for notebook computing, portable instrumentation, and battery-operated digital devices requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LTC3868EUFD-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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving aerospace, industrial, automotive, and communications markets.
The LTC3868EUFD-1#TRPBF belongs to Linear's high-efficiency DC/DC controller product line, engineered specifically for demanding portable and intermediate-bus power applications where low IQ, precise regulation, and robust fault handling are essential.
FAQ
What is the maximum supported switching frequency for the LTC3868EUFD-1#TRPBF?
The LTC3868EUFD-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 device does not support frequencies beyond 900kHz in any configuration, and exceeding this range may cause instability or undefined behavior in the LTC3868EUFD-1#TRPBF's internal VCO and timing circuits.
Does the LTC3868EUFD-1#TRPBF support DCR current sensing on both channels?
Yes, the LTC3868EUFD-1#TRPBF supports DCR current sensing on both channels via dedicated SENSE1+/SENSE1– and SENSE2+/SENSE2– differential inputs. Each pair interfaces with an external RC network across the inductor to generate a voltage proportional to inductor current. The LTC3868EUFD-1#TRPBF's current comparators use this signal - along with the ITH voltage - to set accurate peak current limits without requiring a discrete sense resistor.
How does the short-circuit latchoff function work on the LTC3868EUFD-1#TRPBF?
The LTC3868EUFD-1#TRPBF implements independent short-circuit latchoff per channel using the SS1/SS2 pins. Once the SS voltage exceeds 2.0V (arming threshold), a 9μA discharge current pulls SS down during output faults. If SS falls below 1.5V (latchoff threshold), the channel shuts down permanently until VIN or RUN is cycled. This mechanism prevents thermal damage during sustained shorts and is fully configurable via external capacitor value on the LTC3868EUFD-1#TRPBF's SS pins.
Can the LTC3868EUFD-1#TRPBF operate with only one channel enabled?
Yes, the LTC3868EUFD-1#TRPBF supports independent channel operation. Pulling RUN1 low disables Channel 1 while Channel 2 remains fully functional with its own soft-start, current limit, and PGOOD1 monitoring. In this configuration, the LTC3868EUFD-1#TRPBF draws only 170μA quiescent current, preserving battery life in asymmetric power architectures where only one rail is active during certain operating modes.
What is the purpose of the EXTVCC pin on the LTC3868EUFD-1#TRPBF?
The EXTVCC pin on the LTC3868EUFD-1#TRPBF provides an alternative power source for the internal INTVCC LDO. When EXTVCC exceeds 4.7V, the device switches from the VIN-powered LDO to the EXTVCC-powered LDO, improving overall system efficiency - especially when powering INTVCC from a clean, high-efficiency downstream rail (e.g., 5V output of Channel 1). This reduces power loss and heat generation within the LTC3868EUFD-1#TRPBF itself.
LTC3868EUFD-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)
LTC3868EUFD-1#TRPBF FAQ
1.How can I place an order for LTC3868EUFD-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3868EUFD-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 LTC3868EUFD-1#TRPBF reliable?
The price and inventory of LTC3868EUFD-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 LTC3868EUFD-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3868EUFD-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3868EUFD-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3868EUFD-1#TRPBF?
LTC3868EUFD-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3868EUFD-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 LTC3868EUFD-1#TRPBF?
For technical support, including LTC3868EUFD-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3868EUFD-1#TRPBF requirements.
6.How does Aetrix verify that LTC3868EUFD-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3868EUFD-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 LTC3868EUFD-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3868EUFD-1#TRPBF?
All LTC3868EUFD-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3868EUFD-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 LTC3868EUFD-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC3868EUFD-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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