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Analog Devices Inc. LTC3859ALMPFE#TRPBF
- Part No.:
- LTC3859ALMPFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3859ALMPFE#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,464
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Product details
Overview
LTC3859ALMPFE#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, 4.5V–38V input range, and AEC-Q100 qualification for automotive start-stop systems.
For engineers reviewing the LTC3859ALMPFE#TRPBF datasheet, LTC3859ALMPFE#TRPBF pinout, LTC3859ALMPFE#TRPBF application, or LTC3859ALMPFE#TRPBF equivalent, key selection criteria include cold-crank operation down to 2.5V VIN, 0.8V/1.2V precision references, phase-lockable 75kHz–850kHz switching, and dual-buck-plus-boost topology support for multi-rail power architectures.
Technical Context
The LTC3859ALMPFE#TRPBF implements constant-frequency current-mode control across three independent channels: two buck controllers with 0.8V reference and one boost controller with 1.2V reference. It supports RSENSE or DCR current sensing and delivers 100% duty cycle capability for the boost synchronous MOSFET even in Burst Mode.
Its OPTI-LOOP compensation enables stable transient response across wide output capacitance and ESR ranges. The PLLIN/MODE pin selects among Burst Mode (28µA IQ), pulse-skipping, or forced continuous conduction mode - each configurable per load condition without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 38V main bias; operates down to 2.5V after startup when biased from boost output or auxiliary supply |
| Buck Output Reference | Precision 0.8V ±12mV over temperature; enables accurate regulation of 0.8V–24V outputs |
| Boost Output Reference | Precision 1.2V ±18mV over temperature; supports up to 60V regulated boost output |
| Quiescent Current | 28µA in Burst Mode with one channel active; extends battery runtime in always-on automotive systems |
| Switching Frequency | Programmable 50kHz–900kHz or phase-lockable 75kHz–850kHz; enables EMI optimization and inductor size reduction |
| Operating Temp Range | –55°C to +150°C junction; qualified per AEC-Q100 Grade MP for under-hood automotive use |
| Package | 38-lead TSSOP (FE); exposed pad PGND for thermal management and low-inductance grounding |
Pinout & Package
Package: 38-lead plastic TSSOP (FE), 5mm × 7mm footprint, exposed thermal pad (Pin 39 = PGND) requiring PCB soldering for rated thermal performance (θJA = 25°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (Pin 1) | Oscillator frequency programming | Resistor-to-GND sets 50kHz–900kHz fixed frequency; GND/INTVCC selects 350kHz/535kHz defaults |
| PLLIN/MODE (Pin 2) | Light-load mode & sync input | GND = Burst Mode (28µA IQ); INTVCC = forced CCM; external clock = phase-locked operation |
| RUN1, RUN2, RUN3 (Pins 9,10,11) | Per-channel enable control | Thresholds at 1.18V–1.32V rising edge; <0.7V shuts down entire IC (10µA shutdown IQ) |
| VFB1, VFB2, VFB3 (Pins 36,14,6) | Feedback voltage inputs | Monitor resistive divider outputs; regulate to 0.8V (buck) or 1.2V (boost) with ±12mV/±18mV accuracy |
| TG1/TG2/TG3, BG1/BG2/BG3 (Pins 32/18/27, 29/21/25) | N-MOSFET gate drivers | High-current floating (TGx) and grounded (BGx) drivers; 1.0–2.5Ω on-resistance; 13–28ns transition times |
| PGOOD1 (Pin 33) | Power-good indicator | Open-drain output asserting when VFB1 deviates >±10% from setpoint; supports system sequencing |
Key Features
| Feature | Design Value |
|---|---|
| Triple-output synchronous control | Dual buck + single boost architecture eliminates need for multiple discrete controllers in multi-rail systems |
| Ultra-low IQ Burst Mode | 28µA quiescent current with one channel active enables >1-week battery hold-up in automotive always-on applications |
| Cold-crank compatibility | Maintains regulation during engine cranking events where input drops to 2.5V post-startup |
| OPTI-LOOP compensation | Adapts loop stability to wide range of ceramic/tantalum output capacitors and ESR values without redesign |
| AEC-Q100 MP grade | Qualified for –55°C to +150°C operation; meets automotive reliability and lifetime requirements for under-hood use |
Applications
| Automotive Start-Stop Systems | Battery-Powered Telematics |
|---|---|
Use Scenario: Power management during engine restart cycles where battery voltage dips to 2.5V–6V. IC Role / Device Role / Timing Role: Triple-output controller maintaining stable 5V, 8.5V, and variable boost rails for MCU, infotainment, and sensor subsystems. Use Value: 28µA Burst Mode IQ preserves battery charge between ignition cycles; cold-crank operation ensures uninterrupted system boot. | Use Scenario: Long-life portable tracking units powered by Li-ion or lead-acid batteries. IC Role / Device Role / Timing Role: Generates isolated buck (5V/3A) and boost (10V/2A) rails from 6–24V input for GPS, cellular modem, and microcontroller. Use Value: 0.8V/1.2V precision references ensure accurate ADC reference and RF front-end biasing; low IQ extends field deployment duration. |
| Distributed DC Power Systems | Multioutput Industrial Controllers |
Use Scenario: Centralized 24V bus powering diverse subassemblies with varying voltage requirements. IC Role / Device Role / Timing Role: Simultaneous generation of 3.3V (buck), 12V (buck), and 28V (boost) from single input rail using shared gate drivers and feedback paths. Use Value: Phase-lockable frequency allows synchronization across multiple LTC3859ALMPFE#TRPBF units to reduce conducted EMI in dense PCB layouts. | Use Scenario: Programmable logic controller (PLC) backplane supplying I/O modules, communication interfaces, and real-time processors. IC Role / Device Role / Timing Role: Provides tightly regulated 5V (core logic), 3.3V (FPGA I/O), and 24V (field-side isolation) rails with independent soft-start and fault reporting. Use Value: TRACK/SS pins enable coordinated power-up sequencing; PGOOD1 and OV3 outputs support system-level fault detection and safe shutdown. |
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 |
|---|---|---|---|
| LTC3859AIFE#TRPBF | Same pinout and function but higher Burst Mode IQ (48µA vs 28µA); rated for –40°C to +125°C only | Not qualified for extended temperature automotive use; unsuitable for under-hood placement | Select when cost sensitivity outweighs ultra-low IQ and extended temperature needs |
| LTC3859ALEUHF#TRPBF | QFN package (UHF) instead of TSSOP (FE); identical electrical specs and –40°C to +125°C rating | Lower θJA (34.7°C/W vs 25°C/W) but no AEC-Q100 MP qualification; requires different PCB layout | Select when board space is constrained and automotive qualification is not required |
Compared with LTC3859AIFE#TRPBF and LTC3859ALEUHF#TRPBF, the LTC3859ALMPFE#TRPBF uniquely combines AEC-Q100 MP grade, –55°C to +150°C operation, and industry-leading 28µA Burst Mode IQ in the TSSOP package - making it the sole choice for high-reliability automotive cold-crank and always-on applications.
Availability
LTC3859ALMPFE#TRPBF is available at Aetrix Electronics and suitable for automotive start-stop systems, battery-operated telematics, and distributed DC power systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3859ALMPFE#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 LTC3859AL product line delivers high-efficiency, multi-output synchronous DC/DC controllers optimized for automotive and industrial applications demanding ultra-low quiescent current, cold-crank resilience, and AEC-Q100 reliability.
FAQ
What is the minimum input voltage for LTC3859ALMPFE#TRPBF after startup?
The LTC3859ALMPFE#TRPBF can operate from as low as 2.5V after startup when biased from the boost converter output or an auxiliary supply - enabling reliable regulation during automotive cold-crank events where battery voltage collapses below 6V. This capability is maintained across its full –55°C to +150°C operating range.
How does LTC3859ALMPFE#TRPBF achieve 28µA quiescent current?
The LTC3859ALMPFE#TRPBF achieves 28µA quiescent current in Burst Mode with one channel active through proprietary circuitry that disables unused internal blocks, reduces bias currents in error amplifiers and oscillators, and minimizes gate driver leakage - all while preserving fast wake-up response and regulation accuracy. This is verified per AEC-Q100 test conditions.
Is LTC3859ALMPFE#TRPBF pin-compatible with other LTC3859 variants?
Yes, the LTC3859ALMPFE#TRPBF is fully pin-compatible with the LTC3859 and LTC3859A families in the same TSSOP package. It shares identical pin functions, electrical timing, and layout requirements - allowing drop-in replacement where ultra-low IQ and extended temperature range are required.
What is the purpose of the OPTI-LOOP compensation in LTC3859ALMPFE#TRPBF?
The OPTI-LOOP compensation in LTC3859ALMPFE#TRPBF dynamically adjusts loop gain and phase margin based on output capacitor ESR and capacitance value - eliminating the need for manual compensation network redesign when changing capacitor types (e.g., ceramic to tantalum) or values across production lots or revisions.
Does LTC3859ALMPFE#TRPBF support synchronization across multiple controllers?
Yes, the LTC3859ALMPFE#TRPBF supports external synchronization via the PLLIN/MODE pin, accepting a 75kHz–850kHz clock to align the rising edge of TG1 with the external clock's rising edge. This enables EMI reduction in multi-phase or multi-controller systems without requiring additional timing ICs.
LTC3859ALMPFE#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:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP-EP
LTC3859ALMPFE#TRPBF FAQ
1.How can I place an order for LTC3859ALMPFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3859ALMPFE#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 LTC3859ALMPFE#TRPBF reliable?
The price and inventory of LTC3859ALMPFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3859ALMPFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3859ALMPFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3859ALMPFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3859ALMPFE#TRPBF?
LTC3859ALMPFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3859ALMPFE#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 LTC3859ALMPFE#TRPBF?
For technical support, including LTC3859ALMPFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3859ALMPFE#TRPBF requirements.
6.How does Aetrix verify that LTC3859ALMPFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3859ALMPFE#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 LTC3859ALMPFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3859ALMPFE#TRPBF?
All LTC3859ALMPFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3859ALMPFE#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 LTC3859ALMPFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3859ALMPFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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