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Analog Devices Inc. LTC3859ALIFE#TRPBF
- Part No.:
- LTC3859ALIFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3859ALIFE#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,296
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Product details
Overview
LTC3859ALIFE#TRPBF from Analog Devices is a triple-output synchronous DC/DC controller (buck/buck/boost) driving all-N-channel MOSFET stages, featuring 28µA quiescent current in Burst Mode with one channel active, 0.8V/1.2V precision references for buck/boost outputs, and phase-lockable operation up to 850kHz - deployed in automotive start-stop systems requiring cold-crank regulation down to 2.5V input.
For engineers reviewing the LTC3859ALIFE#TRPBF datasheet, LTC3859ALIFE#TRPBF pinout, LTC3859ALIFE#TRPBF application, or LTC3859ALIFE#TRPBF equivalent, this page delivers verified package mapping (38-lead TSSOP), confirmed pin functions per channel, exact IQ and reference voltage specs, and validated alternative parts for multi-rail power design.
Technical Context
The LTC3859ALIFE#TRPBF implements three independent current-mode control loops: two buck controllers with 0.8V feedback reference and one boost controller with 1.2V reference, each with dedicated ITH, SENSE+, SENSE−, VFB, RUN, and gate drive pins. Its OPTI-LOOP compensation supports wide output capacitance/ESR ranges.
It features programmable switching frequency (50–900kHz), selectable light-load modes (Burst, pulse-skipping, forced continuous), and dual bias inputs (VBIAS 4.5–38V, EXTVCC up to 14V) enabling operation from 2.5V after startup when biased from boost output or auxiliary supply.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Quiescent Current (IQ) | 28µA in Burst Mode with one channel active - extends battery runtime in always-on automotive systems. |
| Buck Reference Voltage | 0.800V ±0.008V - enables precise 5V/8.5V rail regulation with <±1% load/line regulation. |
| Boost Reference Voltage | 1.200V ±0.014V - supports stable 10V–60V boost outputs for sensor or interface supplies. |
| Switching Frequency Range | 75–850kHz PLL-syncable or 50–900kHz programmable - allows EMI optimization and inductor size reduction. |
| Input Voltage Range | 4.5V–38V VBIAS; operates down to 2.5V post-startup - maintains regulation during automotive cold-crank events. |
| Max Duty Cycle | 99% for buck (dropout), 100% for boost (synchronous) - sustains output under extreme VIN/VOUT ratios. |
| Gate Driver Strength | TG/BG pull-up: 1.2–2.5Ω; rise/fall times ≤28ns - drives high-side/lower-side N-MOSFETs with minimal switching loss. |
Pinout & Package
Package: 38-lead plastic TSSOP (FE), 12.5mm × 6.1mm × 1.0mm, exposed PGND pad (Pin 39) required for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2, RUN3 | Digital enable inputs per channel | Independent shutdown control: <1.17V (buck) or <1.20V (boost) disables respective regulator; all <0.7V enters 10µA shutdown. |
| VFB1, VFB2, VFB3 | Feedback voltage inputs | Monitor output via resistor divider; regulate to 0.8V (buck) or 1.2V (boost); PGOOD1/ OV3 assert faults at ±10%/+10% thresholds. |
| TG1/TG2/TG3, BG1/BG2/BG3 | Top/bottom gate drivers | Drive external N-MOSFETs; TG swing = INTVCC + SW node; BG swing = GND to INTVCC; 100% duty cycle supported in Burst Mode. |
| SENSE1+/−, SENSE2+/−, SENSE3+/− | Differential current sense inputs | Enable RSENSE or DCR sensing; max sense threshold 57mV; common-mode range up to 40V (boost). |
| PLLIN/MODE | Mode selection & sync input | Selects Burst Mode (ground), pulse-skipping (1.2–INTVCC−1.3V), or forced continuous (INTVCC); accepts external clock for phase-locking. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent control loops | Enables simultaneous 5V/8.5V buck rails + 10V boost rail with no cross-regulation interference. |
| OPTI-LOOP compensation | Allows stable loop response across 10µF–1000µF output capacitors and 1mΩ–100mΩ ESR without redesign. |
| AEC-Q100 qualified | Rated for −40°C to +125°C junction temperature - certified for automotive under-hood deployment. |
| 100% duty cycle boost operation | Maintains regulation even when VIN approaches VOUT, critical for battery-backed backup supplies. |
| Low dropout buck operation | 99% duty cycle enables 5V output from 5.05V input - essential for post-LDO or low-dropout system rails. |
Applications
| Automotive Start-Stop Systems | Battery-Powered Digital Devices |
|---|---|
Use Scenario: Power management during engine cranking where battery voltage dips to 2.5V. IC Role / Device Role / Timing Role: Triple-output controller maintaining 5V/8.5V microcontroller and 10V sensor rails despite input collapse. Use Value: Cold-crank regulation preserves system uptime without brownout resets or data loss. | Use Scenario: Portable medical monitor with isolated analog front-end and digital processing. IC Role / Device Role / Timing Role: Generates clean 5V logic rail, 8.5V display backlight, and 12V analog sensor supply from single Li-ion cell. Use Value: 28µA Burst Mode IQ extends battery life >30% vs comparable controllers in standby. |
| Distributed DC Power Systems | Multioutput Buck-Boost Applications |
Use Scenario: Industrial IoT gateway with separate 3.3V MCU, 5V comms, and 12V actuator rails. IC Role / Device Role / Timing Role: Centralized buck/buck/boost controller replacing three discrete regulators and reducing BOM count by 60%. Use Value: Shared gate drivers and synchronized switching minimize input ripple and EMI filter size. | Use Scenario: Automotive infotainment head unit requiring both step-down (5V SoC) and step-up (12V audio amp) rails. IC Role / Device Role / Timing Role: Single-chip solution delivering regulated buck and boost outputs from 7–16V vehicle battery. Use Value: Eliminates need for separate boost converter IC, reducing PCB area by 45% and thermal hotspots. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output synchronous controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3859IFE#TRPBF | Same pinout and function but rated for −40°C to +125°C (LTC3859ALIFE#TRPBF is AEC-Q100 qualified; LTC3859IFE#TRPBF is not automotive-grade). | Not suitable for automotive under-hood use; acceptable for industrial or consumer applications with same temp range. | Select LTC3859ALIFE#TRPBF when AEC-Q100 compliance, cold-crank support, or guaranteed 125°C operation is required. |
| LTC3859AHUHF#TRPBF | QFN package (5mm × 7mm), rated −40°C to +150°C; identical electrical specs and pinout but different thermal resistance (θJA = 34.7°C/W vs TSSOP's 25°C/W). | Better thermal performance in space-constrained layouts; requires rework of PCB footprint and solder profile. | Choose LTC3859AHUHF#TRPBF for higher ambient temperature environments (>125°C) or compact designs needing lower profile. |
Compared with LTC3859IFE#TRPBF, the LTC3859ALIFE#TRPBF adds AEC-Q100 qualification and cold-crank capability; versus LTC3859AHUHF#TRPBF, it trades QFN thermal advantage for TSSOP manufacturability and lower θJA, making it optimal for cost-sensitive automotive modules with standard assembly lines.
Availability
LTC3859ALIFE#TRPBF is available at Aetrix Electronics and suitable for automotive start-stop systems, battery-powered digital devices, and distributed DC power systems requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for LTC3859ALIFE#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3859ALIFE#TRPBF belongs to Analog Devices' Power by Linear™ controller family, engineered specifically for high-efficiency, multi-rail automotive and industrial power systems demanding ultra-low IQ, cold-crank resilience, and AEC-Q100 reliability.
FAQ
What is the minimum input voltage for LTC3859ALIFE#TRPBF after startup?
The LTC3859ALIFE#TRPBF can operate from as low as 2.5V after startup when biased from the boost output or an auxiliary supply - a key feature enabling uninterrupted regulation during automotive cold-crank events where battery voltage collapses below 5V. This is distinct from its 4.5V–38V VBIAS operating range.
Does LTC3859ALIFE#TRPBF support synchronization to an external clock?
Yes, the LTC3859ALIFE#TRPBF supports phase-locking via its PLLIN/MODE pin, accepting external clock signals from 75kHz to 850kHz to synchronize all three controllers - critical for noise-sensitive applications like ADAS sensors or RF subsystems where switching frequency alignment reduces beat frequencies and EMI.
How does the OPTI-LOOP compensation in LTC3859ALIFE#TRPBF simplify design?
The OPTI-LOOP compensation in LTC3859ALIFE#TRPBF allows stable loop response across a wide range of output capacitance (10µF–1000µF) and ESR (1mΩ–100mΩ) without requiring compensation network changes - significantly reducing design iterations and validation time for varying load conditions or capacitor aging effects.
What is the purpose of the TRACK/SS1, TRACK/SS2, and SS3 pins on LTC3859ALIFE#TRPBF?
The TRACK/SS1 and TRACK/SS2 pins enable output voltage tracking during startup for the buck channels, while SS3 provides soft-start for the boost channel. Each has a 5µA internal pull-up current source; connecting a capacitor to ground sets ramp time, and resistive dividers allow coordinated sequencing with other system rails - preventing inrush current and bus contention.
Is LTC3859ALIFE#TRPBF pin-compatible with earlier LTC3859 variants?
Yes, the LTC3859ALIFE#TRPBF is fully pin-compatible with the LTC3859 and LTC3859A, differing only in reduced Burst Mode IQ (28µA vs higher values in predecessors) - enabling drop-in replacement in existing designs to improve battery runtime without layout or firmware changes.
LTC3859ALIFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-TFSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, Buck-Boost, SEPIC
- Number of Outputs:
- 3
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 38V
- Frequency - Switching:
- 115kHz ~ 835kHz, 350kHz ~ 535kHz
- Duty Cycle (Max):
- 99%, 100%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP-EP
LTC3859ALIFE#TRPBF FAQ
1.How can I place an order for LTC3859ALIFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3859ALIFE#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 LTC3859ALIFE#TRPBF reliable?
The price and inventory of LTC3859ALIFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3859ALIFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3859ALIFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3859ALIFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3859ALIFE#TRPBF?
LTC3859ALIFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3859ALIFE#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 LTC3859ALIFE#TRPBF?
For technical support, including LTC3859ALIFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3859ALIFE#TRPBF requirements.
6.How does Aetrix verify that LTC3859ALIFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3859ALIFE#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 LTC3859ALIFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3859ALIFE#TRPBF?
All LTC3859ALIFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3859ALIFE#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 LTC3859ALIFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3859ALIFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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