My Inquiry
My Account
Analog Devices Inc. LTC3859IFE#TRPBF
- Part No.:
- LTC3859IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3859IFE#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,102
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3859IFE#TRPBF from Analog Devices is a triple-output synchronous DC/DC controller supporting buck/buck/boost topologies with all-N-channel MOSFET drive capability. It delivers 0.8V ±1% buck regulation (channels 1 & 2), 1.2V ±1% boost regulation (channel 3), phase-lockable 75–850kHz switching, and 55μA no-load quiescent current - enabling high-efficiency power management in automotive start-stop and battery-powered digital systems.
For engineers reviewing the LTC3859IFE#TRPBF datasheet, LTC3859IFE#TRPBF pinout, LTC3859IFE#TRPBF application, or LTC3859IFE#TRPBF equivalent, key selection criteria include its triple independent control loops, cold-crank operation down to 2.5V input, OPTI-LOOP compensation for wide output capacitor/ESR tolerance, and selectable light-load modes (Burst Mode®, pulse-skipping, or forced continuous).
Technical Context
The LTC3859IFE#TRPBF implements three independent constant-frequency current-mode controllers: two 180° out-of-phase buck regulators and one boost regulator synchronized to channel 1. Each channel features dedicated ITH error amplifier outputs, TRACK/SS pins for soft-start or voltage tracking, and separate RUN pins for individual enable/disable control.
Its gate drivers support high-side N-MOSFETs via BOOST1–3 charge pumps (up to 76V on BOOST3), deliver 1.0Ω pull-down resistance on TG3/BG3, and provide precise current sensing using RSENSE or DCR with programmable trip thresholds (43–57mV). The device operates from 4.5V–38V bias input or as low as 2.5V when biased from boost output or auxiliary supply.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Buck/Buck/Boost - enables dual regulated low-voltage rails plus one higher-voltage rail from single input. |
| Input Voltage Range | 4.5V to 38V VBIAS; supports cold-crank down to 2.5V after startup when biased from boost output. |
| Output Voltage Accuracy | ±1% at VFB1/VFB2 = 0.800V (buck); ±1% at VFB3 = 1.200V (boost) over –40°C to 125°C. |
| Switching Frequency | Programmable 50kHz–900kHz or phase-lockable 75kHz–850kHz - enables EMI optimization and multi-rail synchronization. |
| Quiescent Current | 55μA (one channel active in Sleep Mode) - extends runtime in always-on battery systems. |
| Current Sensing | RSENSE or DCR-based with 43–57mV max threshold - supports accurate overcurrent protection across load range. |
| Duty Cycle Range | Up to 99% for buck dropout; 100% for boost synchronous MOSFET - maintains regulation under extreme input/output ratios. |
Pinout & Package
Package: 38-pin TSSOP (FE) with exposed PGND pad (Pin 39), rated for –40°C to 125°C operating junction temperature. Thermal resistance θJA = 25°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2, RUN3 | Digital enable inputs per channel | Independent shutdown control: <1.20V disables buck/boost; <0.7V shuts down entire IC (IQ = 14μA). |
| VFB1, VFB2, VFB3 | Feedback voltage inputs | Compare output voltage (via resistor divider) against 0.800V (buck) or 1.200V (boost) reference for regulation. |
| TRACK/SS1, TRACK/SS2, SS3 | Soft-start/tracking control | Capacitor-connected ramp sets startup time; resistor dividers enable output voltage tracking during power-up. |
| TG1/TG2/TG3, BG1/BG2/BG3 | N-MOSFET gate drivers | High-current floating (TGx) and grounded (BGx) drivers with 1.0–2.5Ω on-resistance - support fast switching with low loss. |
| SENSE1+/–, SENSE2+/–, SENSE3+/– | Differential current sense inputs | Measure inductor current via RSENSE or DCR; SENSE3+ supplies current to comparator for boost channel. |
| PLLIN/MODE | Sync input / light-load mode select | Accepts external clock for synchronization; selects Burst Mode® (ground), pulse-skipping (1.2–INTVCC–1.3V), or forced CCM (INTVCC). |
| PGOOD1, OV3 | Open-drain status indicators | PGOOD1 signals buck1 regulation (±10%); OV3 flags boost overvoltage (>110% setpoint) - enable system-level fault handling. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent control loops | Enables simultaneous regulation of two buck outputs (e.g., 5V/8.5V) and one boost output (e.g., 10V or up to 60V) with no cross-talk. |
| OPTI-LOOP™ compensation | Allows stable loop response across wide range of output capacitors (ceramic/tantalum) and ESR values without redesign. |
| Low IQ sleep mode | 55μA quiescent current with one channel active - critical for automotive always-on applications with strict leakage budgets. |
| 100% duty cycle boost operation | Maintains regulation even when input approaches output voltage - eliminates need for external LDO in high-VIN scenarios. |
| Programmable light-load behavior | Selectable Burst Mode®, pulse-skipping, or forced continuous conduction - balances efficiency vs. output ripple per system requirement. |
Applications
| Automotive Start-Stop Systems | Battery-Powered Digital Devices |
|---|---|
Use Scenario: Power management during engine cranking where battery voltage drops to 2.5V. IC Role / Device Role / Timing Role: Triple-output controller maintaining 5V microcontroller rail, 8.5V display rail, and 10V sensor rail despite input collapse. Use Value: 2.5V cold-crank operation ensures uninterrupted system function without brownout resets. |
Use Scenario: Portable medical monitor requiring long battery life and multiple isolated voltage rails. IC Role / Device Role / Timing Role: Primary power controller generating 3.3V logic, 5V USB interface, and 12V analog front-end from single Li-ion cell stack. Use Value: 55μA sleep IQ extends runtime by >30% versus comparable controllers in standby mode. |
| Distributed DC Power Systems | Industrial Control Units |
Use Scenario: Centralized 24V bus powering diverse subsystems with varying voltage needs. IC Role / Device Role / Timing Role: Local DC/DC controller converting 24V to 12V motor drive, 5V I/O, and 28V analog signal conditioning. Use Value: Independent TRACK/SS pins allow coordinated soft-start across all rails to prevent inrush current overload. |
Use Scenario: Programmable logic controller (PLC) requiring robust power under wide industrial temperature range. IC Role / Device Role / Timing Role: Main power supervisor delivering 3.3V FPGA core, 5V communication interface, and 15V analog acquisition rail. Use Value: –40°C to 125°C guaranteed operation and 1.2V boost reference stability ensure reliability in uncontrolled environments. |
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 |
|---|---|---|---|
| LTC3855IUFD#TRPBF | Dual-buck-only (no boost channel); 32-pin QFN; lower max frequency (675kHz); 60μA IQ. | Cannot replace LTC3859IFE#TRPBF in boost-required designs; suitable only when third rail is generated externally. | Choose when system requires only dual buck regulation and smaller footprint is prioritized. |
| MP2918GL-Z | Triple buck (no boost); 40-pin QFN; 125°C rating; 75μA IQ; integrated MOSFET drivers only (no external FET support). | Lacks boost topology and external N-MOSFET flexibility; limited to low-power applications (<10A per channel). | Select for cost-sensitive, space-constrained designs where all three rails are buck-derived and integrated drivers suffice. |
Compared with LTC3855IUFD#TRPBF and MP2918GL-Z, the LTC3859IFE#TRPBF uniquely supports buck/buck/boost with external N-MOSFETs, enabling higher power, wider VIN/VOUT ratios, and true 60V boost capability - making it irreplaceable in cold-crank automotive and multi-rail industrial systems.
Availability
LTC3859IFE#TRPBF is available at Aetrix Electronics and suitable for automotive start-stop systems, battery-operated digital devices, and distributed DC power systems requiring stable component supply, extended temperature operation, and high-efficiency multi-rail conversion.
Supply support for LTC3859IFE#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 LTC3859IFE#TRPBF belongs to Analog Devices' Power by Linear™ family of high-efficiency DC/DC controllers, engineered specifically for demanding multi-rail power architectures in automotive and industrial applications where cold-crank resilience, low IQ, and flexible topology support are essential.
FAQ
What is the minimum input voltage required for LTC3859IFE#TRPBF startup?
The LTC3859IFE#TRPBF requires ≥5V on VBIAS to initiate startup. However, once running and biased from the boost output or an auxiliary supply, it sustains operation down to 2.5V input - a critical feature for automotive cold-crank conditions. This behavior is enabled by internal undervoltage lockout thresholds (4.15V rising, 3.5V falling) and bias path management between VBIAS, EXTVCC, and INTVCC.
How does LTC3859IFE#TRPBF support voltage tracking during power-up?
The LTC3859IFE#TRPBF uses dedicated TRACK/SS1 and TRACK/SS2 pins for buck channels and SS3 for the boost channel. Connecting a resistor divider from a master supply to TRACK/SS1/2 causes the buck outputs to ramp proportionally during startup. For the boost channel, SS3 accepts a ramp voltage (e.g., from a capacitor charged by 1µA internal current source) to control rise time - ensuring controlled sequencing without external circuitry.
Can LTC3859IFE#TRPBF drive both high-side and low-side N-channel MOSFETs in all three channels?
Yes. The LTC3859IFE#TRPBF integrates high-current floating gate drivers (TG1–3) for high-side N-MOSFETs and grounded drivers (BG1–3) for low-side N-MOSFETs across all three channels. BOOST1–3 pins supply bootstrapped voltage to TG drivers, supporting up to 76V on BOOST3. Gate driver on-resistances (1.0–2.5Ω) and fast transition times (13–28ns) ensure efficient switching with external discrete FETs.
What are the supported light-load operating modes for LTC3859IFE#TRPBF?
The LTC3859IFE#TRPBF offers three selectable light-load modes via the PLLIN/MODE pin: Burst Mode® operation (pin grounded), pulse-skipping mode (pin biased to 1.2V–INTVCC–1.3V), or forced continuous conduction mode (pin tied to INTVCC). Each mode directly impacts efficiency, output ripple, and EMI profile - allowing designers to optimize for battery life, noise sensitivity, or transient response.
Does LTC3859IFE#TRPBF provide fault protection features beyond overvoltage?
Yes. In addition to PGOOD1 (buck1 regulation monitor) and OV3 (boost overvoltage flag), the LTC3859IFE#TRPBF includes current foldback limiting during short-circuit conditions, undervoltage lockout (UVLO) with hysteresis, thermal shutdown, and individual RUN pin control for per-channel disable. These features collectively protect external MOSFETs, inductors, and downstream loads without requiring external supervision circuitry.
LTC3859IFE#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
LTC3859IFE#TRPBF FAQ
1.How can I place an order for LTC3859IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3859IFE#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 LTC3859IFE#TRPBF reliable?
The price and inventory of LTC3859IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3859IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3859IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3859IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3859IFE#TRPBF?
LTC3859IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3859IFE#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 LTC3859IFE#TRPBF?
For technical support, including LTC3859IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3859IFE#TRPBF requirements.
6.How does Aetrix verify that LTC3859IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3859IFE#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 LTC3859IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3859IFE#TRPBF?
All LTC3859IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3859IFE#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 LTC3859IFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3859IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3859IFE#TRPBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
