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Analog Devices Inc. LTC3859ALMPFE#PBF
- Part No.:
- LTC3859ALMPFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-TFSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3859ALMPFE#PBF.pdf
- Description:
- IC REG CTRLR MULT TOP 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,608
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Product details
Overview
LTC3859ALMPFE#PBF 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 cold-crank operation down to 2.5V. It supports phase-lockable switching up to 850kHz and delivers regulated outputs of 0.8V (buck), 0.8V (buck), and 1.2V (boost) references.
For engineers reviewing the LTC3859ALMPFE#PBF datasheet, LTC3859ALMPFE#PBF pinout, LTC3859ALMPFE#PBF application, or LTC3859ALMPFE#PBF equivalent, key selection criteria include its ultra-low IQ in sleep mode, triple-output topology flexibility, cold-crank capability below 2.5V after startup, and dual-buck-plus-boost architecture for multi-rail automotive power systems.
Technical Context
The LTC3859ALMPFE#PBF 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. Each channel features dedicated ITH error amplifier outputs, SENSE± differential current sensing, and programmable soft-start via TRACK/SS1,2 and SS3 pins.
Its PLLIN/MODE pin enables dynamic load-efficiency optimization-Burst Mode (28µA IQ), pulse-skipping, or forced continuous conduction-while FREQ pin allows resistor-programmable switching frequency from 50kHz to 900kHz or external synchronization from 75kHz to 850kHz. The device integrates gate drivers with matched rise/fall times and precise dead-time control for TG/BG pairs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V–38V main bias; operates down to 2.5V after startup when biased from boost output or auxiliary supply |
| Buck Reference Voltage | 0.800V ±1.0% (0°C–85°C), enabling precise 0.8V–24V output regulation with low dropout |
| Boost Reference Voltage | 1.200V ±1.0% (0°C–85°C), supporting up to 60V boost output with 100% duty cycle capability |
| Quiescent Current | 28µA in Burst Mode with one channel active-critical for always-on automotive battery systems |
| Switching Frequency | Programmable 50kHz–900kHz or phase-locked 75kHz–850kHz; supports synchronized multi-phase designs |
| Operating Temp Range | –55°C to +150°C junction, qualified per AEC-Q100 Grade MP for extended automotive reliability |
| Package | 38-lead plastic TSSOP (FE package), exposed PGND pad for thermal and electrical integrity |
Pinout & Package
38-lead plastic TSSOP (FE package) with exposed PGND pad (Pin 39), requiring soldering to PCB for rated thermal performance (θJA = 25°C/W). Pin mapping validated per Rev. D datasheet Figure 1 (TSSOP top view).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (Pin 1) | Oscillator frequency control | Resistor-to-GND sets 50kHz–900kHz; tied to GND/INTVCC for fixed 350kHz/535kHz |
| PLLIN/MODE (Pin 2) | Sync input & light-load mode select | External clock sync; ground = Burst Mode, INTVCC = forced CCM, mid-voltage = pulse-skipping |
| RUN1/RUN2/RUN3 (Pins 9–11) | Per-channel enable/disable | Thresholds: RUN1 <1.17V, RUN2/RUN3 <1.20V disables respective channel; all <0.7V shuts down IC |
| VFB1/VFB2/VFB3 (Pins 36,14,6) | Feedback voltage inputs | Monitor output via resistive divider; regulate to 0.8V (buck) or 1.2V (boost) reference |
| TG1/TG2/TG3 (Pins 32,18,27) | Top-gate N-MOS drivers | Floating high-side gate drives with 1.2Ω pull-up/pull-down, 25ns rise/fall (CL=3300pF) |
| PGOOD1 (Pin 33) | Power-good indicator | Open-drain output asserting when VFB1 deviates >±10% from setpoint |
Key Features
| Feature | Design Value |
|---|---|
| Triple-output topology | Dual buck + single boost architecture enables independent regulation of three rails-e.g., 5V/8.5V/10V-without external controllers |
| Ultra-low IQ sleep mode | 28µA with one buck channel active extends runtime in battery-backed automotive modules during standby |
| Cold-crank support | Maintains regulation through 2.5V input dips-essential for start-stop systems where battery voltage collapses transiently |
| OPTI-LOOP compensation | Allows stable loop response across wide ESR/capacitance variations, simplifying output capacitor selection for diverse loads |
| AEC-Q100 MP grade | Qualified over –55°C to +150°C junction temperature, meeting automotive reliability requirements for under-hood applications |
Applications
| Automotive Start-Stop Systems | Always-On Telematics Modules |
|---|---|
Use Scenario: Power management in vehicles with engine auto-shutdown at idle, requiring uninterrupted 5V/8.5V rails during cranking events. IC Role / Device Role / Timing Role: Triple-output controller regulating buck1 (5V MCU core), buck2 (8.5V infotainment), and boost (10V sensor bias) from 12V battery. Use Value: 28µA IQ preserves battery charge during prolonged stop; cold-crank down to 2.5V ensures no rail collapse during restart. | Use Scenario: Always-on GPS/4G module in parked vehicle, drawing microamp-level standby current for location reporting. IC Role / Device Role / Timing Role: Primary power controller delivering regulated 5V (processor), 3.3V (radio), and 12V (antenna bias) from Li-ion or lead-acid source. Use Value: Burst Mode IQ of 28µA enables >1-year battery life; AEC-Q100 MP grade ensures reliability at –40°C ambient. |
| Distributed Automotive ECUs | Industrial Battery-Powered Gateways |
Use Scenario: Compact ECU powering CAN transceiver, microcontroller, and analog sensors in space-constrained chassis locations. IC Role / Device Role / Timing Role: Single-chip solution generating 3.3V (MCU I/O), 5V (CAN PHY), and adjustable boost (sensor excitation) from 9V–16V nominal bus. Use Value: 38-pin TSSOP footprint minimizes board area; 100% duty cycle boost enables >VIN outputs for precision sensor biasing. | Use Scenario: Remote IoT gateway operating on sealed lead-acid battery in unheated outdoor cabinet, requiring multi-rail power with long shelf life. IC Role / Device Role / Timing Role: Central controller managing 12V (cellular modem), 5V (ARM processor), and 3.3V (Wi-Fi SoC) from 12V battery with cold-weather resilience. Use Value: –55°C to +150°C rating guarantees operation at –40°C ambient; 28µA IQ reduces self-discharge to negligible levels. |
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#PBF | Same pinout and functionality but rated for –40°C to +125°C (not –55°C); Burst Mode IQ is 35µA (vs. 28µA) | Suitable for cabin electronics but not under-hood or extreme cold environments | Select when AEC-Q100 Grade I suffices and extended low-temp operation is unnecessary |
| LTC3859ALEFE#PBF | Commercial-grade variant (–40°C to +125°C); identical electrical specs except wider temp range tolerance and no AEC-Q100 certification | Targeted at industrial or consumer applications without automotive qualification requirements | Choose for cost-sensitive non-automotive designs where MP-grade reliability is not mandated |
Compared with LTC3859AIFE#PBF and LTC3859ALEFE#PBF, the LTC3859ALMPFE#PBF uniquely delivers –55°C start-up capability, 28µA ultra-low IQ, and full AEC-Q100 MP qualification-making it the only option for mission-critical automotive under-hood power systems requiring guaranteed operation at extreme low temperatures.
Availability
LTC3859ALMPFE#PBF is available at Aetrix Electronics and suitable for automotive start-stop systems, always-on telematics modules, and distributed ECUs requiring stable component supply with AEC-Q100 compliance and extended temperature resilience.
Supply support for LTC3859ALMPFE#PBF 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 controllers optimized for automotive power systems requiring cold-crank resilience, ultra-low standby current, and AEC-Q100 qualification.
FAQ
What is the minimum input voltage for LTC3859ALMPFE#PBF during cold-crank conditions?
The LTC3859ALMPFE#PBF maintains regulation with input as low as 2.5V after startup when biased from the boost output or an auxiliary supply-enabling reliable operation during automotive cranking events where battery voltage dips below 6V. This capability is explicitly verified per datasheet Section "DESCRIPTION" and Absolute Maximum Ratings.
Does LTC3859ALMPFE#PBF support synchronization to an external clock?
Yes, the LTC3859ALMPFE#PBF supports external synchronization via the PLLIN/MODE pin (Pin 2), accepting clock inputs from 75kHz to 850kHz to align switching edges across multiple converters-critical for noise-sensitive automotive systems. This function is confirmed in the "PIN FUNCTIONS" section and Electrical Characteristics table (fSYNC parameter).
What is the purpose of the EXTVCC pin on LTC3859ALMPFE#PBF?
The EXTVCC pin (Pin 23) connects an external 4.7V–14V supply to bypass the internal VBIAS-powered LDO, reducing power loss and heat generation when high-current gate drive is required. Its switchover threshold is 4.5V–4.7V with 200mV hysteresis, as specified in the Electrical Characteristics table under VLDOHYS.
How does the OPTI-LOOP compensation work in LTC3859ALMPFE#PBF?
OPTI-LOOP compensation in the LTC3859ALMPFE#PBF adjusts loop dynamics via the ITH1/ITH2/ITH3 pins, allowing stable closed-loop response across wide ranges of output capacitance and ESR-eliminating need for iterative compensation tuning. This is documented in the "DESCRIPTION" section and validated in Typical Performance Characteristic plots (e.g., G09, G18).
Is LTC3859ALMPFE#PBF pin-compatible with earlier LTC3859 variants?
Yes, the LTC3859ALMPFE#PBF is fully pin-compatible with the LTC3859 and LTC3859A, sharing identical pinout, package dimensions, and functional interface-enabling drop-in replacement while delivering lower Burst Mode IQ (28µA vs. 35µA) and extended temperature qualification (–55°C to +150°C).
LTC3859ALMPFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-TFSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- 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#PBF FAQ
1.How can I place an order for LTC3859ALMPFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3859ALMPFE#PBF 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#PBF reliable?
The price and inventory of LTC3859ALMPFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3859ALMPFE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3859ALMPFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3859ALMPFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3859ALMPFE#PBF?
LTC3859ALMPFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3859ALMPFE#PBF 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#PBF?
For technical support, including LTC3859ALMPFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3859ALMPFE#PBF requirements.
6.How does Aetrix verify that LTC3859ALMPFE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3859ALMPFE#PBF 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#PBF meets industry standards.
7.What is the process for return or replacement of LTC3859ALMPFE#PBF?
All LTC3859ALMPFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3859ALMPFE#PBF, 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#PBF part is unused and in its original packaging.
Return procedure for LTC3859ALMPFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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