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Analog Devices Inc. LTC3868IGN-1#TRPBF
- Part No.:
- LTC3868IGN-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3868IGN-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,545
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Product details
Overview
LTC3868IGN-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., 3.3V/5A and 8.5V/3.5A), supports RSENSE or DCR current sensing, operates from 4V to 24V input, and achieves 170μA quiescent current in single-channel sleep mode - ideal for battery-powered portable instruments and distributed power systems.
For engineers reviewing the LTC3868IGN-1#TRPBF datasheet, LTC3868IGN-1#TRPBF pinout, LTC3868IGN-1#TRPBF application, or LTC3868IGN-1#TRPBF equivalent, key selection criteria include its out-of-phase dual-channel architecture (reducing input capacitance and EMI), OPTI-LOOP® compensation for wide output capacitor/ESR tolerance, programmable frequency (50–900kHz), and robust short-circuit protection with latchoff and foldback.
Technical Context
The LTC3868IGN-1#TRPBF implements a constant-frequency current-mode control architecture with two independent 180° out-of-phase controllers, each driving external N-channel MOSFETs. Its dual-error-amplifier topology enables precise regulation of both outputs via separate VFB1/VFB2 feedback paths and independent ITH1/ITH2 compensation nodes.
It integrates dual gate drivers (TG1/BG1 and TG2/BG2) with 2.5Ω pull-up and 1.5Ω pull-down on top-side drivers, supports flexible light-load operation (Burst Mode®, pulse-skipping, or forced continuous), and features internal LDOs powered from VIN or EXTVCC to supply INTVCC at 5.1V ±3% - enabling efficient self-biasing from regulated outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 24V - supports wide-range intermediate bus voltages and multi-cell Li-ion or lead-acid battery inputs. |
| Output Voltage Range | 0.8V to 14V per channel - set via external resistor divider; precision 0.8V ±1.5% reference enables accurate low-voltage rail generation. |
| Quiescent Current | 170μA (one channel active, sleep mode) - extends runtime in always-on portable instrumentation and IoT edge devices. |
| Switching Frequency | 50kHz to 900kHz (programmable) - allows optimization of size (higher fSW → smaller inductors/caps) vs. efficiency (lower fSW → reduced switching loss). |
| Current Sensing | RSENSE or DCR - eliminates sense resistor losses in high-current applications by supporting inductor DCR sensing with offset calibration. |
| Protection Features | Output overvoltage (±10% PGOOD trip), short-circuit latchoff (SS-pin timed), foldback current limiting - ensures system-level reliability without external supervision circuitry. |
| Package | 28-Lead Plastic SSOP - surface-mount package with 0.635mm pitch; compatible with standard reflow processes and manual inspection. |
Pinout & Package
Package: 28-Lead Plastic SSOP (0.635mm pitch), –40°C to +85°C operating temperature range. Exposed pad not present (unlike QFN variant); thermal performance characterized with θJA = 90°C/W.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+, SENSE2+ | Differential current sense (+) input | Connects to high-side of RSENSE or DCR network; sets peak current limit with SENSE– and ITH voltage. |
| SENSE1–, SENSE2– | Differential current sense (–) input | Reference node for current comparator; supplies bias current when > INTVCC – 0.5V - critical for DCR sensing accuracy. |
| VFB1, VFB2 | Feedback input | Monitors regulated output via resistive divider; error amplifier compares to 0.8V reference to adjust ITH voltage and duty cycle. |
| ITH1, ITH2 | Error amplifier output / compensation node | Controls peak current threshold; connects to RC network for OPTI-LOOP® compensation - stabilizes loop across wide COUT/ESR ranges. |
| SS1, SS2 | Soft-start / latchoff timer input | Charged by 1μA internal current source; ramps VOUT during startup; also discharges during short-circuit to trigger latchoff at 1.5V threshold. |
| RUN1, RUN2 | Enable control input | Digital shutdown pins: <1.26V disables respective channel; both <0.7V forces full shutdown (8μA IQ). |
| PGOOD1 | Power-good indicator | Open-drain output asserting low when VFB1 deviates >±10% from target - used for sequencing or system fault signaling. |
| TG1, TG2 | Top-gate driver output | Drives gate of high-side N-MOSFET; floating output referenced to SW node; 2.5Ω pull-up enables fast turn-on. |
| BG1, BG2 | Bottom-gate driver output | Drives gate of synchronous rectifier N-MOSFET; ground-referenced; 1.1Ω pull-down ensures rapid turn-off. |
| BOOST1, BOOST2 | Bootstrap supply | Provides floating bias for top-gate drivers; connected via capacitor to SWx - enables high-side drive without external charge pump. |
| SW1, SW2 | Switch node | Connection point between inductor, top/bottom MOSFETs, and bootstrap capacitor - high dV/dt node requiring careful layout. |
| VIN | Main input supply | Primary power source for internal LDO (INTVCC); bypassed to SGND with ≥4.7μF ceramic capacitor to suppress ripple. |
| EXTVCC | External bias input | Optional 4.7–14V supply to power INTVCC via dedicated LDO - improves efficiency by avoiding VIN-to-5.1V dropout loss. |
| INTVCC | Internal LDO output | 5.1V ±3% regulated supply powering gate drivers and analog circuitry; must be decoupled with ≥4.7μF low-ESR capacitor. |
| SGND | Small-signal ground | Analog reference for feedback, current sense, and error amplifiers - must be routed separately from PGND to avoid noise coupling. |
| PGND | Power ground | Return path for bottom MOSFET sources and input capacitors - low-impedance connection essential for stable current sensing. |
| FREQ | Frequency programming | Resistor-to-GND sets VCO frequency (50–900kHz); tied to GND or INTVCC selects fixed 350kHz or 535kHz - simplifies design without external clock. |
| PLLIN/MODE | Synchronization / light-load mode select | Ground = Burst Mode®; INTVCC = forced continuous; 1.2–3.8V = pulse-skipping - enables dynamic efficiency optimization per load condition. |
Key Features
| Feature | Design Value |
|---|---|
| Out-of-phase dual-channel operation | Reduces RMS input ripple current by ~30%, allowing smaller input bulk capacitance and lower EMI filter cost. |
| OPTI-LOOP® compensation | Enables stable loop response across 10× variation in output capacitance (e.g., 22μF to 220μF) and ESR (5mΩ to 50mΩ) without redesign. |
| Programmable light-load modes | Burst Mode® (170μA IQ), pulse-skipping, or forced continuous - selectable per application need for efficiency vs. output ripple trade-off. |
| Short-circuit protection with latchoff | SS-pin based timeout (configurable via CSS) provides controlled shutdown after sustained overcurrent - prevents thermal runaway without external timers. |
| DCR current sensing support | Eliminates power loss and board space of discrete sense resistors in high-current (>5A) designs while maintaining ±5% current limit accuracy. |
| 99% maximum duty cycle | Enables ultra-low dropout operation (e.g., 5V→4.95V) - critical for post-regulation in battery-powered systems near end-of-discharge. |
Applications
| Portable Test Equipment | Industrial Data Acquisition |
|---|---|
|
Use Scenario: Handheld multimeters and oscilloscope probes requiring isolated dual-rail supplies (±15V analog, 3.3V digital) from a single Li-ion cell. IC Role / Device Role / Timing Role: Dual-phase controller generating tightly regulated 3.3V/5A and 8.5V/3.5A rails with minimal input capacitance and low quiescent current. Use Value: 170μA sleep IQ extends battery life beyond 20 hours; out-of-phase operation reduces conducted EMI into sensitive analog front-ends. |
Use Scenario: Modular PLC I/O modules powered from 24V industrial bus, needing local 5V and 3.3V rails with high immunity to voltage transients. IC Role / Device Role / Timing Role: Synchronous buck controller delivering 5V/4A and 3.3V/3A with RSENSE sensing and robust OVP/short-circuit protection. Use Value: Output overvoltage protection (±10% trip) and latchoff prevent damage during field wiring faults; wide 4–24V input accommodates brownout conditions. |
| Medical Point-of-Care Devices | Automotive Infotainment Power |
|
Use Scenario: Battery-backed ultrasound handhelds requiring quiet, low-noise 1.8V FPGA core and 5V sensor interface rails from 7.4V Li-Poly pack. IC Role / Device Role / Timing Role: Dual-channel controller with Burst Mode® operation minimizing standby power while maintaining fast transient response. Use Value: OPTI-LOOP® ensures stable regulation despite aging electrolytic output caps; soft-start prevents inrush current tripping battery protection ICs. |
Use Scenario: In-vehicle navigation units drawing power from 9–16V automotive battery, needing clean 5V USB and 3.3V SoC rails with thermal resilience. IC Role / Device Role / Timing Role: High-efficiency dual buck controller supporting EXTVCC bias from 5V rail to reduce heat dissipation under hot ambient conditions. Use Value: INTVCC powered from regulated 5V output cuts thermal load by ~300mW vs. VIN-derived bias; 125°C junction rating ensures reliability at 85°C ambient. |
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 external FET support); fixed 500kHz frequency; no DCR sensing. | Targeted at space-constrained consumer power supplies; lacks programmable light-load modes and latchoff protection. | Select MP2918GL-Z only if board area is critical and external MOSFETs are unnecessary; LTC3868IGN-1#TRPBF offers superior flexibility and protection for industrial use. |
| ISL95836IRZ | Intel VR12.5-compliant dual-phase controller; supports adaptive voltage positioning (AVP); requires external PMBus interface for configuration. | Designed for CPU/GPU VRMs in computing platforms; includes telemetry and dynamic VID scaling - over-engineered for general-purpose DC/DC. | Choose ISL95836IRZ only for Intel platform compliance; LTC3868IGN-1#TRPBF provides simpler, standalone control with broader input/output range and lower IQ. |
Compared with MP2918GL-Z and ISL95836IRZ, the LTC3868IGN-1#TRPBF uniquely balances high integration (dual controllers, gate drivers, LDOs) with design flexibility (RSENSE/DCR sensing, programmable frequency, three light-load modes) and robust protection - making it optimal for portable, industrial, and medical power systems where reliability and efficiency coexist.
Availability
LTC3868IGN-1#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, distributed DC power systems, and battery-operated digital devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC3868IGN-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 industrial, automotive, communications, and healthcare markets.
The LTC3868IGN-1#TRPBF belongs to Linear's high-efficiency DC/DC controller product line, engineered specifically for dual-output, low-IQ power conversion in space- and energy-constrained applications such as portable test gear and medical electronics.
FAQ
What is the minimum input voltage supported by the LTC3868IGN-1#TRPBF?
The LTC3868IGN-1#TRPBF supports a minimum input voltage of 4V, enabling compatibility with partially discharged 2-cell Li-ion batteries (≈4.2V fully charged, down to ≈4.0V) and regulated 5V intermediate bus systems. Operation below 4V triggers undervoltage lockout (UVLO) at 3.6V (rising) to protect internal circuitry - ensuring reliable startup and shutdown behavior in battery-powered LTC3868IGN-1#TRPBF designs.
Does the LTC3868IGN-1#TRPBF support DCR current sensing on both channels?
Yes, the LTC3868IGN-1#TRPBF supports DCR current sensing on both channels via dedicated SENSE1+/SENSE1– and SENSE2+/SENSE2– differential inputs. Each pair accepts common-mode voltages up to 16V and includes internal bias current sources that enable accurate DCR measurement without external op-amps - a key capability confirmed in the "PIN FUNCTIONS" section and electrical characteristics table for LTC3868IGN-1#TRPBF.
How does the short-circuit latchoff function work on the LTC3868IGN-1#TRPBF?
The LTC3868IGN-1#TRPBF uses the SS1 and SS2 pins as dual independent latchoff timers. Once the SS voltage exceeds 2.0V (arming threshold), a 9μA discharge current activates if VFB drops below 70% of regulation. If SS falls to 1.5V (latchoff threshold), the channel shuts down permanently until VIN or RUN is cycled. This behavior is explicitly documented in the "Short-Circuit Latchoff" section of the LTC3868IGN-1#TRPBF datasheet and verified in typical performance curves.
Can the LTC3868IGN-1#TRPBF operate with only one channel enabled?
Yes, the LTC3868IGN-1#TRPBF supports independent channel control via RUN1 and RUN2 pins. Pulling RUN1 low disables Channel 1 while Channel 2 remains fully operational - and vice versa. In single-channel operation, quiescent current drops to 170μA (sleep mode), and all protections (PGOOD, OVP, latchoff) remain active per enabled channel - a feature confirmed in the "Shutdown and Start-Up" section of the LTC3868IGN-1#TRPBF datasheet.
What is the purpose of the EXTVCC pin on the LTC3868IGN-1#TRPBF?
The EXTVCC pin on the LTC3868IGN-1#TRPBF provides an alternative input to the internal LDO that generates INTVCC. When EXTVCC exceeds 4.7V, the VIN-based LDO turns off and the EXTVCC LDO powers INTVCC at 5.1V - reducing power loss and heat generation. This allows efficient biasing from a pre-regulated 5V rail (e.g., one of the LTC3868IGN-1#TRPBF's own outputs), as detailed in the "INTVCC/EXTVCC Power" section of the datasheet.
LTC3868IGN-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
LTC3868IGN-1#TRPBF FAQ
1.How can I place an order for LTC3868IGN-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3868IGN-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 LTC3868IGN-1#TRPBF reliable?
The price and inventory of LTC3868IGN-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 LTC3868IGN-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3868IGN-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3868IGN-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3868IGN-1#TRPBF?
LTC3868IGN-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3868IGN-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 LTC3868IGN-1#TRPBF?
For technical support, including LTC3868IGN-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3868IGN-1#TRPBF requirements.
6.How does Aetrix verify that LTC3868IGN-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3868IGN-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 LTC3868IGN-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3868IGN-1#TRPBF?
All LTC3868IGN-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3868IGN-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 LTC3868IGN-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC3868IGN-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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