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Analog Devices Inc. LT8618IDDB-3.3#TRPBF
- Part No.:
- LT8618IDDB-3.3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT8618IDDB-3.3#TRPBF.pdf
- Description:
- IC REG BUCK 3.3V 100MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,430
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Product details
Overview
LT8618IDDB-3.3#TRPBF from Analog Devices is a monolithic synchronous step-down DC/DC converter delivering 100mA at fixed 3.3V output, operating from 3.4V to 60V input (65V transient), with 2.5µA quiescent current in Burst Mode and 35ns minimum on-time. It uses constant-frequency current-mode control up to 2.2MHz and targets industrial sensors and 4–20mA loop supplies requiring high efficiency and low-noise regulation.
For engineers reviewing the LT8618IDDB-3.3#TRPBF datasheet, LT8618IDDB-3.3#TRPBF pinout, LT8618IDDB-3.3#TRPBF application, or LT8618IDDB-3.3#TRPBF equivalent, key selection criteria include input voltage range, ultralow IQ at light load, ±7.5% power-good accuracy, fixed 3.3V output tolerance, and DFN-10 package thermal performance for space-constrained industrial designs.
Technical Context
The LT8618IDDB-3.3#TRPBF implements current-mode control with internal compensation, enabling stable operation without external loop components. Its 35ns minimum on-time supports high VIN/VOUT ratios (e.g., 48V-to-3.3V) at 2MHz switching, while Burst Mode reduces IQ to 2.5µA under light loads without audible noise.
It features an open-drain PG flag asserting when VOUT is within ±7.5% of 3.3V and no fault exists, and integrates top/bottom NMOS switches with 3Ω/1.3Ω typical RDS(on). The EN/UV pin provides 1.05V rising threshold with 50mV hysteresis for precise input undervoltage lockout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±3% (3.2V–3.4V) over temperature and line, enabling direct replacement of LDOs in noise-sensitive analog rails. |
| Input Voltage Range | 3.4V to 60V continuous (65V transient), supporting wide-input industrial and automotive housekeeping applications. |
| Quiescent Current | 2.5µA in Burst Mode at 48VIN→3.3VOUT, extending battery life in always-on sensor nodes. |
| Switching Frequency | 200kHz to 2.2MHz (set by RT resistor), allowing EMI optimization and small external inductor selection (e.g., 33µH at 2MHz). |
| Power-Good Accuracy | ±7.5% window around 3.3V (i.e., 3.05V–3.55V), providing reliable system reset signaling without external comparators. |
| Minimum On-Time | 35ns typical, enabling high-step-down conversion (e.g., 48V→3.3V) at 2MHz without pulse-skipping instability. |
| Operating Temperature | –40°C to +125°C junction, qualified for industrial and extended-temperature embedded systems. |
Pinout & Package
LT8618IDDB-3.3#TRPBF uses a 10-lead 3mm × 2mm plastic DFN package with exposed thermal pad (Pin 11 = GND), θJA = 76°C/W. Pinout matches LT8618-3.3 variant: OUT (Pin 6) is the regulated 3.3V output node; FB pin is not used.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BST | Bootstrap capacitor connection | Drives top NMOS gate above VIN; requires 47nF ceramic cap placed adjacent to IC for reliable high-side switching. |
| SW | Switch node | Connects directly to inductor; must be minimized in PCB layout to reduce EMI and switching losses. |
| BIAS | Bias supply input | Tie to VOUT (3.3V) to reduce VIN current draw; enables efficient operation when output ≥3.3V. |
| INTVCC | Internal 3.4V regulator bypass | Requires ≥1µF ceramic capacitor to ground; powers internal logic and drivers-no external loading permitted. |
| RT | Frequency setting resistor | Resistor to GND sets fSW from 200kHz–2.2MHz; determines inductor size and EMI profile. |
| OUT | Fixed 3.3V output | Regulated output node; connects to load and output capacitor; internal feedback divider eliminates external resistors. |
| TR/SS | Soft-start/tracking control | Capacitor to GND programs output ramp rate; enables controlled startup and voltage tracking in multi-rail systems. |
| PG | Power-good open-drain flag | Pulls low until VOUT reaches 3.05V–3.55V and remains low during faults; requires external pull-up. |
| EN/UV | Enable/undervoltage lockout | 1.05V rising threshold with 50mV hysteresis; resistor divider from VIN enables programmable UVLO. |
| VIN | Main input supply | Must be bypassed locally with low-ESR capacitor; negative terminal tied to exposed GND pad for thermal and electrical integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow quiescent current | 2.5µA IQ in Burst Mode enables >10-year battery life in remote IoT sensors powered from coin cells or energy harvesters. |
| Fixed 3.3V output with internal divider | Eliminates external feedback resistors, reducing BOM count and layout area while ensuring ±3% output accuracy across temperature. |
| 35ns minimum on-time | Supports high VIN/VOUT ratios at high frequencies (e.g., 48V→3.3V @ 2MHz), avoiding frequency foldback and maintaining predictable EMI. |
| Integrated power MOSFETs | 3Ω top / 1.3Ω bottom RDS(on) deliver >90% efficiency at 30mA (12VIN→3.3VOUT), reducing thermal design complexity. |
| Open-drain PG flag with ±7.5% window | Provides deterministic power sequencing without external monitoring circuitry, simplifying FPGA/CPU reset integration. |
Applications
| Industrial Sensors | 4–20mA Current Loops |
|---|---|
Use Scenario: Powering MEMS pressure sensors and thermocouple amplifiers in hazardous-area transmitters. IC Role / Device Role / Timing Role: Primary 3.3V housekeeping supply regulating from 24V loop-powered bus or auxiliary 48V rail. Use Value: 2.5µA IQ extends loop compliance margin; ±3% output ensures ADC reference stability and sensor calibration integrity. | Use Scenario: Providing isolated 3.3V bias for DACs, op-amps, and microcontrollers in two-wire field instruments. IC Role / Device Role / Timing Role: Fixed-output buck converter generating clean, low-noise supply independent of loop current variation. Use Value: Burst Mode eliminates switching noise during low-current periods, preserving signal-to-noise ratio in precision analog front-ends. |
| Flow Meters | Automotive Housekeeping Supplies |
Use Scenario: Supplying ultrasonic time-of-flight measurement circuits and magnetic flow sensor excitation drivers. IC Role / Device Role / Timing Role: High-efficiency 3.3V source tolerant of wide input transients (e.g., load dump, cold crank). Use Value: 60V continuous / 65V transient rating avoids need for upstream TVS clamping; 35ns on-time maintains regulation during 12V brownouts. | Use Scenario: Powering infotainment MCU peripherals, CAN transceivers, and display backlight controllers in body electronics modules. IC Role / Device Role / Timing Role: Secondary point-of-load regulator deriving 3.3V from 5V or 12V vehicle bus. Use Value: –40°C to +125°C operation meets AEC-Q100 Grade I requirements; PG flag synchronizes subsystem wake-up with main rail stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8618EDDB-3.3#TRPBF | Same pinout and electrical specs, but rated for 0°C to 125°C junction (E-grade) vs. –40°C to 125°C (I-grade) for LT8618IDDB-3.3#TRPBF. | Not suitable for extended-temperature industrial environments where ambient exceeds 0°C at startup. | Select LT8618IDDB-3.3#TRPBF for guaranteed operation down to –40°C ambient in outdoor or unheated enclosures. |
| LT8618JDDB-3.3#TRPBF | Same functionality with extended junction temperature range (–40°C to 150°C) and higher thermal robustness (θJA = 76°C/W same, but J-grade qualification). | Targeted at under-hood automotive or high-ambient industrial applications exceeding 125°C case temperature. | Choose LT8618JDDB-3.3#TRPBF only if sustained operation above 125°C junction is required; otherwise LT8618IDDB-3.3#TRPBF offers optimal cost/performance balance. |
Compared with LT8618EDDB-3.3#TRPBF, LT8618IDDB-3.3#TRPBF guarantees full specification compliance at –40°C startup, critical for cold-climate instrumentation; versus LT8618JDDB-3.3#TRPBF, it trades 150°C capability for lower unit cost and identical performance below 125°C, making it ideal for general-purpose industrial 3.3V point-of-load regulation.
Availability
LT8618IDDB-3.3#TRPBF is available at Aetrix Electronics and suitable for industrial sensors, 4–20mA current loops, and automotive housekeeping supplies requiring stable component supply, long-term manufacturability, and guaranteed temperature-grade compliance.
Supply support for LT8618IDDB-3.3#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 LT8618 family delivers compact, high-efficiency synchronous buck regulation for space- and power-constrained applications where ultralow quiescent current, wide input range, and fixed-output simplicity are essential.
FAQ
What is the guaranteed operating temperature range for LT8618IDDB-3.3#TRPBF?
The LT8618IDDB-3.3#TRPBF is specified and guaranteed over a junction temperature range of –40°C to +125°C. This I-grade qualification ensures full electrical performance compliance-including output voltage accuracy, quiescent current, and power-good timing-across that full range, making it suitable for industrial environments with uncontrolled ambient conditions.
Does LT8618IDDB-3.3#TRPBF require external feedback resistors?
No, LT8618IDDB-3.3#TRPBF does not require external feedback resistors. It integrates an internal resistor divider to regulate the OUT pin precisely to 3.3V, eliminating two external components and associated layout sensitivity. This fixed-output architecture simplifies design, improves accuracy, and reduces board area compared to adjustable variants like LT8618.
How does the PG (Power-Good) pin function on LT8618IDDB-3.3#TRPBF?
The PG pin on LT8618IDDB-3.3#TRPBF is an open-drain output that remains low until the OUT voltage reaches and sustains within ±7.5% of 3.3V (i.e., 3.05V–3.55V) and no fault (e.g., overtemperature, undervoltage) is present. It asserts high only when both conditions are met, providing a reliable system-ready signal for microcontroller reset or enable sequencing without external monitoring.
Can LT8618IDDB-3.3#TRPBF operate from a 48V input to deliver 3.3V efficiently?
Yes, LT8618IDDB-3.3#TRPBF efficiently operates from 48V input to 3.3V output. With its 35ns minimum on-time and 2.2MHz maximum switching frequency, it maintains stable constant-frequency operation without pulse-skipping. At 30mA load, efficiency exceeds 90%, and its 2.5µA Burst Mode IQ minimizes standby power loss in always-on 48V-powered systems.
What is the purpose of the TR/SS pin on LT8618IDDB-3.3#TRPBF?
The TR/SS (Track/Soft-Start) pin on LT8618IDDB-3.3#TRPBF controls output voltage ramp rate during startup and enables output voltage tracking in multi-rail systems. Connecting a capacitor from TR/SS to GND programs soft-start time; applying an external voltage allows the output to track another supply. An internal 2µA pull-up current enables simple RC-based timing without external current sources.
LT8618IDDB-3.3#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.4V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 100mA
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x2)
LT8618IDDB-3.3#TRPBF FAQ
1.How can I place an order for LT8618IDDB-3.3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8618IDDB-3.3#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 LT8618IDDB-3.3#TRPBF reliable?
The price and inventory of LT8618IDDB-3.3#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8618IDDB-3.3#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8618IDDB-3.3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8618IDDB-3.3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8618IDDB-3.3#TRPBF?
LT8618IDDB-3.3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8618IDDB-3.3#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 LT8618IDDB-3.3#TRPBF?
For technical support, including LT8618IDDB-3.3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8618IDDB-3.3#TRPBF requirements.
6.How does Aetrix verify that LT8618IDDB-3.3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8618IDDB-3.3#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 LT8618IDDB-3.3#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8618IDDB-3.3#TRPBF?
All LT8618IDDB-3.3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8618IDDB-3.3#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 LT8618IDDB-3.3#TRPBF part is unused and in its original packaging.
Return procedure for LT8618IDDB-3.3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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