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Analog Devices Inc. LTC3859ALHFE#TRPBF
- Part No.:
- LTC3859ALHFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3859ALHFE#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,344
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Product details
Overview
LTC3859ALHFE#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 and boost outputs respectively, and operation from 4.5V–38V input (or 2.5V post-startup). It enables cold-crank regulation in automotive start-stop systems.
For engineers reviewing the LTC3859ALHFE#TRPBF datasheet, LTC3859ALHFE#TRPBF pinout, LTC3859ALHFE#TRPBF application, or LTC3859ALHFE#TRPBF equivalent, key selection criteria include its triple-output topology, AEC-Q100 qualification, 75kHz–850kHz phase-lockable frequency, OPTI-LOOP compensation, and low-IQ operation across wide temperature range (–40°C to 150°C).
Technical Context
The LTC3859ALHFE#TRPBF implements constant-frequency current-mode control with independent ITH error amplifier outputs per channel, enabling precise current-sense threshold adjustment via external resistors or DCR sensing. Its PLLIN/MODE pin configures light-load behavior-Burst Mode (28µA), pulse-skipping, or forced continuous conduction-across all three regulators simultaneously.
It integrates dual buck controllers with 99% dropout duty cycle and a boost controller supporting up to 60V output, each with dedicated SENSE+/– inputs, VFB references, and gate drivers (TG/BG) optimized for N-MOSFETs. The INTVCC LDO (5.4V typical) powers internal circuitry and supports EXTVCC switchover at 4.7V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Buck/Buck/Boost triple-output synchronous controller for independent voltage rails. |
| Input Voltage Range | 4.5V–38V main bias; operates down to 2.5V after startup using boost output or auxiliary supply. |
| Quiescent Current | 28µA in Burst Mode with one channel active-enables multi-day battery runtime in always-on systems. |
| Reference Voltages | 0.8V ±12mV (buck channels), 1.2V ±18mV (boost channel)-ensures tight output regulation accuracy. |
| Switching Frequency | Programmable 50kHz–900kHz or phase-lockable 75kHz–850kHz-supports EMI optimization and magnetics sizing. |
| Output Voltage Range | Buck: 0.8V–24V; Boost: up to 60V-covers wide industrial and automotive rail requirements. |
| Gate Driver Strength | TG/BG pull-up: 1.2Ω (boost), 2.5Ω (buck); fast rise/fall times (<30ns) support high-efficiency MOSFET switching. |
| Temperature Grade | AEC-Q100 qualified, rated for –40°C to +150°C junction-suitable for under-hood automotive deployment. |
Pinout & Package
Package: 38-lead plastic TSSOP (FE package), 5mm × 7mm footprint, exposed PGND pad (Pin 39) requiring PCB soldering for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (Pin 1) | Oscillator frequency programming | Resistor-to-GND sets 50kHz–900kHz; tied to GND/INTVCC for fixed 350kHz/535kHz. |
| PLLIN/MODE (Pin 2) | Light-load mode & sync input | GND = Burst Mode; INTVCC = forced CCM; external clock = phase-locked operation. |
| RUN1/RUN2/RUN3 (Pins 9–11) | Per-channel enable/disable | Threshold ~1.2V; all <0.7V shuts down entire IC to 10µA shutdown current. |
| VFB1/VFB2/VFB3 (Pins 36/14/6) | Feedback voltage sense inputs | Compare against 0.8V (buck) or 1.2V (boost); PGOOD1 monitors VFB1 only. |
| TG1/TG2/TG3 (Pins 32/18/27) | Top-gate N-MOSFET drivers | Floating drivers with INTVCC swing over SW node-enable high-side N-FET use without P-FET. |
| BG1/BG2/BG3 (Pins 29/21/25) | Bottom-gate N-MOSFET drivers | Ground-referenced drivers sourcing/sinking >1A peak-support synchronous rectification. |
| SENSE1+/–, SENSE2+/–, SENSE3+/– (Pins 37/38,13/12,4/5) | Differential current sense inputs | Support RSENSE or DCR sensing; SENSE3+ supplies current to comparator for boost channel. |
| PGND (Pin 39) | Power ground reference | Exposed pad must be soldered to PCB plane-critical for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Triple-output architecture | Independent buck/buck/boost regulation enables compact multi-rail power systems without discrete controllers. |
| OPTI-LOOP compensation | Allows stable loop response across wide range of output capacitor ESR and capacitance values-reduces design iterations. |
| 100% duty cycle capability (boost) | Enables seamless transition to dropout during cold-crank events where VIN drops below VOUT. |
| Adjustable soft-start/tracking | Internal 5µA current source on TRACK/SS pins enables controlled ramp-up and coordinated sequencing with other rails. |
| AEC-Q100 qualification | Validated for automotive applications including start-stop and always-on subsystems-meets stress test requirements. |
| Low-noise current sensing | Sub-µA input bias on SENSE pins minimizes offset errors-improves current limit accuracy at light loads. |
Applications
| Automotive Start-Stop Systems | Industrial Distributed Power |
|---|---|
Use Scenario: Vehicle engine restarts after brief stop; battery voltage dips to 2.5V during cranking. IC Role / Device Role / Timing Role: Triple-output controller maintains regulated 5V, 8.5V, and adaptive 10V/variable boost rail despite input collapse. Use Value: 2.5V minimum operating voltage and 99% buck duty cycle prevent brownout of infotainment and ADAS modules. | Use Scenario: Factory automation PLC with isolated 24V, 12V, and 5V rails powering logic, I/O, and sensors. IC Role / Device Role / Timing Role: Centralized buck/buck/boost controller replaces three discrete solutions-reducing BOM count and layout area. Use Value: Single-chip integration cuts board space by >40% versus discrete controllers while maintaining independent rail control. |
| Battery-Powered Telematics | Multioutput Telecom Equipment |
Use Scenario: Cellular gateway powered by 12V lead-acid battery with 24/7 GPS tracking and LTE transmission. IC Role / Device Role / Timing Role: LTC3859ALHFE#TRPBF manages 5V (modem), 3.3V (MCU), and 12V (RF front-end) with ultra-low 28µA sleep current. Use Value: 28µA quiescent current extends battery life to >10 days in deep sleep-critical for remote asset monitoring. | Use Scenario: Base station power shelf requiring 48V input conversion to 12V, 5V, and 3.3V for digital processing, memory, and PHY layers. IC Role / Device Role / Timing Role: High-efficiency triple controller delivers >92% efficiency at full load across all outputs with programmable frequency. Use Value: Phase-lockable 850kHz operation enables synchronized switching-reducing conducted EMI in dense telecom chassis. |
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 rated for –40°C to 125°C; higher Burst Mode IQ (≈35µA vs 28µA). | Suitable for non-automotive industrial environments where extended temperature is not required. | Select when AEC-Q100 and 150°C operation are unnecessary-lower cost alternative with identical functionality. |
| LTC3859ALEUHF#TRPBF | QFN package (5mm × 7mm), same temp grade (–40°C to 125°C); identical electrical specs except θJA = 34.7°C/W vs 25°C/W. | Better thermal performance in space-constrained layouts; requires different PCB land pattern than TSSOP. | Choose for high-density designs needing lower thermal resistance and smaller footprint-no change in schematic. |
Compared with LTC3859AIFE#TRPBF and LTC3859ALEUHF#TRPBF, the LTC3859ALHFE#TRPBF uniquely combines AEC-Q100 qualification, 150°C operation, and lowest 28µA Burst Mode IQ-making it the only option for under-hood automotive deployments demanding both reliability and ultra-low standby power.
Availability
LTC3859ALHFE#TRPBF is available at Aetrix Electronics and suitable for automotive start-stop systems, battery-powered telematics, and industrial distributed power applications requiring stable component supply, long-term lifecycle support, and AEC-Q100 compliance.
Supply support for LTC3859ALHFE#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 targeting automotive and industrial applications where cold-crank resilience, low quiescent current, and AEC-Q100 reliability are mandatory.
FAQ
What is the minimum input voltage for LTC3859ALHFE#TRPBF after startup?
The LTC3859ALHFE#TRPBF can operate from as low as 2.5V after startup when biased from the boost output or an auxiliary supply-enabling reliable regulation during automotive cold-crank events where battery voltage collapses. This is distinct from its 4.5V–38V main VBIAS operating range and is critical for maintaining power to safety-critical ECUs.
How does the PLLIN/MODE pin configure light-load operation on LTC3859ALHFE#TRPBF?
The PLLIN/MODE pin on LTC3859ALHFE#TRPBF selects light-load behavior across all three channels: grounded or floating (via internal 100kΩ pull-down) enables Burst Mode (28µA IQ); tied to INTVCC forces continuous conduction; biased to 1.2V–(INTVCC–1.3V) enables pulse-skipping. An external clock applied here synchronizes switching and forces continuous mode.
Does LTC3859ALHFE#TRPBF support RSENSE and DCR current sensing simultaneously?
Yes, the LTC3859ALHFE#TRPBF supports both RSENSE and DCR current sensing per channel-each SENSE+/– pair accepts either method. For buck channels, SENSE– sources current when above INTVCC; for boost, SENSE3+ supplies current to the comparator. No external components are needed to switch between methods-configuration is purely layout-based.
What is the purpose of the EXTVCC pin on LTC3859ALHFE#TRPBF?
The EXTVCC pin on LTC3859ALHFE#TRPBF connects to an external 4.7V–14V supply to power the INTVCC LDO, bypassing the internal VBIAS-regulated LDO. This improves efficiency and thermal performance when a clean, low-impedance auxiliary rail is available-common in systems with pre-regulated 5V or 12V supplies feeding the controller.
Can LTC3859ALHFE#TRPBF regulate all three outputs independently with different voltages?
Yes, LTC3859ALHFE#TRPBF provides fully independent regulation: Buck channels use 0.8V reference (VFB1/VFB2) for outputs from 0.8V–24V; the boost channel uses 1.2V reference (VFB3) for outputs up to 60V. Each has dedicated feedback, current sense, soft-start, and enable pins-allowing asymmetric configurations such as 5V/8.5V/12V or 3.3V/5V/adaptive boost.
LTC3859ALHFE#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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP-EP
LTC3859ALHFE#TRPBF FAQ
1.How can I place an order for LTC3859ALHFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3859ALHFE#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 LTC3859ALHFE#TRPBF reliable?
The price and inventory of LTC3859ALHFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3859ALHFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3859ALHFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3859ALHFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3859ALHFE#TRPBF?
LTC3859ALHFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3859ALHFE#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 LTC3859ALHFE#TRPBF?
For technical support, including LTC3859ALHFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3859ALHFE#TRPBF requirements.
6.How does Aetrix verify that LTC3859ALHFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3859ALHFE#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 LTC3859ALHFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3859ALHFE#TRPBF?
All LTC3859ALHFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3859ALHFE#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 LTC3859ALHFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3859ALHFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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