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Analog Devices Inc. LTC7818IUJ#PBF
- Part No.:
- LTC7818IUJ#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- -
- Datasheet:
-
LTC7818IUJ#PBF.pdf
- Description:
- BUCK/BUCK/BOOST SYNC CTL, 40V, 3
- Quantity:
- Payment:
- Shipping:
Inventory:1,051
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Product details
Overview
LTC7818IUJ#PBF from Analog Devices is a triple-output synchronous DC/DC controller (buck/buck/boost) driving all-N-channel MOSFET stages, operating from 4.5V–40V input with 14μA no-load quiescent current, 3MHz max switching frequency, and AEC-Q100 qualification for automotive cold-crank operation down to 1V input. It enables compact, high-efficiency power architectures in start-stop vehicle ECUs.
For engineers reviewing the LTC7818IUJ#PBF datasheet, LTC7818IUJ#PBF pinout, LTC7818IUJ#PBF application, or LTC7818IUJ#PBF equivalent, key selection criteria include its triple-output topology, PassThru™ boost capability at 100% duty cycle, OPTI-LOOP® compensation, spread spectrum EMI reduction, and precise 0.8V/1.2V references for buck/boost regulation.
Technical Context
The LTC7818IUJ#PBF implements constant-frequency current-mode control across three independent channels: two synchronous buck controllers (Channel 1 & 2) and one synchronous boost controller (Channel 3). Each channel features programmable light-load modes (Burst, Pulse-Skipping, Forced Continuous), independent RUN pins, and dedicated ITH error amplifiers with 1.8mmho transconductance.
Its architecture supports phase-lockable operation up to 3MHz via FREQ and PLLIN/SPREAD pins, uses RSENSE or DCR current sensing, and integrates a 5.1V INTVCC LDO with EXTVCC switchover at 4.7V. The boost channel includes PassThru™ operation, IMON3 current monitor output, and VPRG3-selectable fixed outputs (8V/10V) or adjustable regulation via VFB3.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Buck/Buck/Boost triple-output synchronous controller - enables single-chip 3-rail power supply for ADAS domain controllers or infotainment SoCs. |
| Input Voltage Range | 4.5V to 40V (VBIAS); post-startup operation down to 1V (VIN) when biased from boost output - supports automotive battery transients including cold crank. |
| Quiescent Current | 14μA typical (14V→3.3V, Channel 1 active); 1.5μA shutdown - extends battery runtime in always-on vehicle modules. |
| Switching Frequency | Programmable 100kHz–3MHz; phase-lockable up to 3MHz - allows EMI optimization and small external component selection. |
| Reference Voltages | 0.8V ±12mV (buck), 1.2V ±20mV (boost) - ensures tight output regulation across temperature and load for safety-critical rails. |
| Package | 40-lead 6mm × 6mm QFN with exposed thermal pad - provides low θJA (33°C/W) for thermally constrained automotive PCBs. |
| AEC-Q100 Grade | Grade I (–40°C to +125°C junction) - qualified for under-hood and cabin electronics per automotive reliability standards. |
Pinout & Package
40-lead plastic QFN (6mm × 6mm), exposed pad soldered to PCB ground for thermal and electrical integrity. Pin 41 is the exposed pad (GND).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2, RUN3 (8,9,10) | Independent enable inputs | Each controls startup/shutdown of corresponding buck or boost channel; all pulled <0.7V disables entire IC with 1.5μA IQ. |
| VPRG3 (16) | Boost output voltage programming | Selects fixed 8V (GND), 10V (INTVCC), or adjustable mode (floating) - eliminates need for external feedback divider in common automotive boost configurations. |
| IMON3 (7) | Boost inductor current monitor | Analog voltage output (0.4V–1.4V) proportional to boost channel current - enables real-time current limiting and telemetry without sense resistor. |
| PLLIN/SPREAD (34) | Sync input / spread spectrum control | Accepts external clock (0.1–3MHz) for synchronization; driven high enables ±12%/+15% frequency dithering to reduce peak EMI emissions. |
| MODE (1) | Light-load operation mode select | GND = Burst Mode (ultra-low IQ); INTVCC = Forced Continuous (low noise); 100kΩ to INTVCC = Pulse-Skipping (balance). |
Key Features
| Feature | Design Value |
|---|---|
| PassThru™ Boost Operation | Enables 100% duty cycle in boost channel when VIN ≥ VOUT - maintains regulated output during automotive battery dips without dropout or recovery delay. |
| OPTI-LOOP® Compensation | Allows stable loop response across wide range of output capacitor ESR and capacitance values - simplifies design for varying load conditions and aging effects. |
| Spread Spectrum Modulation | Reduces peak conducted/radiated EMI by spreading energy over ±12% to +15% bandwidth - helps meet CISPR 25 Class 5 without added shielding or filtering. |
| Dual Buck + Single Boost Integration | Replaces three discrete controllers in multi-rail systems - reduces BOM count, PCB area, and layout complexity for ADAS camera modules and radar processors. |
| Low-IQ Sleep Mode | Draws only 15–24μA (one/all channels active) when EXTVCC=0V and SENSE1–≥3.2V - enables efficient partial-system wake-up in vehicle body control units. |
Applications
| Automotive ADAS Domain Controller | Start-Stop Vehicle ECU Power |
|---|---|
Use Scenario: Powers SoC core (1.2V), I/O (3.3V), and sensor interface (10V) rails from 9–16V battery with cold-crank survival. IC Role / Device Role / Timing Role: Triple-output controller managing independent buck (SoC core/I/O) and boost (sensor bias) supplies with coordinated soft-start and fault reporting. Use Value: Eliminates need for external sequencers; PassThru™ maintains 10V rail during 1V battery dip; PGOOD1 and OV3 provide system-level fault signaling. |
Use Scenario: Supplies microcontroller, CAN transceiver, and memory in engine control unit during repeated stop/start cycles. IC Role / Device Role / Timing Role: Primary power controller delivering regulated 5V and 3.3V from variable battery input, with boost maintaining auxiliary 12V rail. Use Value: 14μA IQ extends battery life during extended parking; AEC-Q100 Grade I ensures reliability at 125°C junction; spread spectrum meets OEM EMI limits. |
| Industrial Motor Drive Auxiliary Supply | Avionics Sensor Hub Power |
Use Scenario: Generates isolated gate driver (15V), logic (5V), and analog (3.3V) rails from 24V industrial bus with high dv/dt immunity. IC Role / Device Role / Timing Role: High-voltage tolerant controller (40V max VBIAS) regulating multiple rails while rejecting bus transients via robust RUN pin UVLO. Use Value: Wide 4.5–40V input accommodates 24V/36V/48V systems; 3MHz switching enables ultra-small magnetics; EXTVCC switchover improves efficiency. |
Use Scenario: Powers inertial measurement unit (IMU), pressure sensors, and data concentrator in aircraft environmental monitoring system. IC Role / Device Role / Timing Role: Triple-output controller delivering precision 3.3V, 5V, and adjustable 10V rails with low-noise forced continuous mode and thermal derating support. Use Value: 0.8V/1.2V references ensure ±1% output accuracy; –40°C to +125°C operation meets DO-160 thermal requirements; IMON3 enables health monitoring. |
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 |
|---|---|---|---|
| LTC7817IUJ#PBF | Dual-buck-only (no boost channel); identical package, pinout, and feature set except missing BOOST3, IMON3, VPRG3, OV3 pins. | Suitable only where third rail is generated externally or not required - cannot replace LTC7818IUJ#PBF in boost-dependent applications like sensor biasing. | Select LTC7817IUJ#PBF when system requires only dual-buck regulation and cost reduction is prioritized over integration. |
| MP2965AGU-Z | Triple-output buck/buck/buck (no boost); 2.2MHz max fSW; 25μA IQ; non-AEC-Q100; 32-pin QFN (5×5mm). | Lacks PassThru™, spread spectrum, and cold-crank capability below 3V - unsuitable for automotive start-stop or low-VIN boost needs. | Consider MP2965AGU-Z only for industrial non-automotive applications requiring smaller footprint and lower cost, with no boost requirement. |
Compared with LTC7817IUJ#PBF and MP2965AGU-Z, the LTC7818IUJ#PBF uniquely delivers integrated boost with PassThru™, AEC-Q100 qualification, and sub-1V cold-crank operation - making it the sole option for automotive multi-rail systems requiring regulated high-side bias generation.
Availability
LTC7818IUJ#PBF is available at Aetrix Electronics and suitable for automotive ADAS domain controllers, start-stop vehicle ECUs, industrial motor drive auxiliary supplies, and avionics sensor hubs requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for LTC7818IUJ#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 automotive, industrial, communications, and aerospace markets with precision power, signal chain, and RF solutions.
The LTC7818IUJ#PBF belongs to Analog Devices' Power by Linear™ controller family, engineered specifically for high-reliability, multi-rail automotive power systems demanding ultra-low quiescent current, EMI robustness, and cold-crank resilience.
FAQ
What is the minimum input voltage for LTC7818IUJ#PBF after startup?
The LTC7818IUJ#PBF can operate from an input supply as low as 1V after startup when biased from the boost output or another auxiliary supply. This capability is critical for surviving automotive cold-crank events where battery voltage collapses to 1V while maintaining regulation on all three outputs. The device achieves this via internal biasing architecture that decouples control circuitry from the main VBIAS rail once running.
How does the PassThru™ feature work in LTC7818IUJ#PBF?
In the LTC7818IUJ#PBF, PassThru™ enables the boost channel to operate at 100% duty cycle when VIN ≥ VOUT, allowing the output to directly follow the input with minimal dropout. This avoids regulation loss during battery voltage recovery phases in start-stop vehicles. The feature is automatic and requires no external configuration - it activates based on internal voltage comparison between VIN and the programmed VOUT3 level.
Can LTC7818IUJ#PBF support spread spectrum operation, and how is it enabled?
Yes, the LTC7818IUJ#PBF supports spread spectrum modulation to reduce peak EMI emissions. It is enabled by driving the PLLIN/SPREAD pin high (to INTVCC), which dithers the oscillator frequency by –12% to +15% around the nominal value. This feature is fully integrated and requires no external components, helping systems comply with CISPR 25 Class 5 radiated emission limits without additional filtering or shielding.
What are the voltage reference accuracies for buck and boost outputs in LTC7818IUJ#PBF?
The LTC7818IUJ#PBF provides a precision 0.8V ±12mV (±1.5%) reference for buck outputs and a 1.2V ±20mV (±1.7%) reference for the boost output, specified over –40°C to +125°C junction temperature. These tight tolerances ensure stable output regulation across automotive temperature extremes and load variations, supporting safety-critical applications such as ADAS vision processing rails.
Is LTC7818IUJ#PBF pin-compatible with other members of the LTC781x family?
No, the LTC7818IUJ#PBF is not pin-compatible with LTC7817 or LTC7819 due to distinct pin functions: LTC7818 includes BOOST3, IMON3, VPRG3, and OV3 pins absent in dual-buck variants. While sharing the same 40-lead QFN package outline, the pin assignments differ significantly - requiring unique PCB layout. Migration requires schematic and layout revision, not drop-in replacement.
LTC7818IUJ#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- -
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, Boost
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 40V
- Frequency - Switching:
- 100kHz ~ 3MHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
LTC7818IUJ#PBF FAQ
1.How can I place an order for LTC7818IUJ#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7818IUJ#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 LTC7818IUJ#PBF reliable?
The price and inventory of LTC7818IUJ#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7818IUJ#PBF is usually 5 days.
3.What payment methods are accepted for LTC7818IUJ#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7818IUJ#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7818IUJ#PBF?
LTC7818IUJ#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7818IUJ#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 LTC7818IUJ#PBF?
For technical support, including LTC7818IUJ#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7818IUJ#PBF requirements.
6.How does Aetrix verify that LTC7818IUJ#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7818IUJ#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 LTC7818IUJ#PBF meets industry standards.
7.What is the process for return or replacement of LTC7818IUJ#PBF?
All LTC7818IUJ#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7818IUJ#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 LTC7818IUJ#PBF part is unused and in its original packaging.
Return procedure for LTC7818IUJ#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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