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Analog Devices Inc. LTC3642EDD-3.3#TRPBF
- Part No.:
- LTC3642EDD-3.3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3642EDD-3.3#TRPBF.pdf
- Description:
- IC REG BUCK 3.3V 50MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,500
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Product details
Overview
LTC3642EDD-3.3#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, synchronous step-down DC/DC converter with integrated high-side and low-side MOSFETs, delivering up to 50mA output current at a fixed 3.3V output, operating from 4.5V to 45V input, and drawing only 12µA quiescent current in Burst Mode® operation. It is used in industrial control supplies and battery-operated devices requiring robust, low-power regulation.
For engineers reviewing the LTC3642EDD-3.3#TRPBF datasheet, LTC3642EDD-3.3#TRPBF pinout, LTC3642EDD-3.3#TRPBF application, or LTC3642EDD-3.3#TRPBF equivalent, key selection considerations include its 3.3V fixed output, programmable peak current limit (25–115mA), internal soft-start, precise RUN pin threshold (1.21V rising), and compatibility with ceramic input/output capacitors in space-constrained DFN packages.
Technical Context
The LTC3642EDD-3.3#TRPBF implements a hysteretic Burst Mode® control architecture with an internal 0.8V feedback reference and 5mV comparator hysteresis, enabling high efficiency across load currents from 100µA to 50mA. Its peak current-limited switching uses internal P-channel high-side and N-channel low-side MOSFETs with 3.0Ω and 1.5Ω on-resistance respectively.
Startup is managed via a precision RUN pin comparator (1.21V enable threshold, 110mV hysteresis) and dual soft-start: internal 0.75ms ramp plus optional external capacitor on SS pin. Input protection includes undervoltage lockout (3.75V to 4.5V range) and overvoltage lockout (47V to 52V range), with tolerance for 60V transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 45V - supports wide industrial and automotive supply rails, including 12V, 24V, and 36V systems. |
| Output Voltage | Fixed 3.3V ±1.2% - tightly regulated for powering microcontrollers, sensors, and logic interfaces without external feedback resistors. |
| Max Output Current | 50mA - sufficient for low-power embedded subsystems, current loops, and auxiliary rails. |
| Quiescent Current | 12µA typical in Burst Mode® - enables multi-year battery life in always-on sensor nodes and portable instruments. |
| Peak Current Limit | Programmable 25mA to 115mA via ISET resistor - allows optimization of inductor size, efficiency, and transient response for specific load profiles. |
| Package | 8-lead 3mm × 3mm DFN (DD) with exposed GND pad - thermally enhanced for >1W dissipation in compact layouts. |
| Protection Features | UVLO (3.75V–4.5V), OVLO (47V–52V), and 60V transient tolerance - ensures reliable operation in harsh electrical environments. |
Pinout & Package
Package: 8-lead (3mm × 3mm) plastic DFN (DD) with exposed thermal pad (Pin 9 = GND), rated for –40°C to 125°C junction temperature. Exposed pad must be soldered to PCB ground plane for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch node | Connection point between internal high-side and low-side MOSFETs; ties to inductor; carries high di/dt switching current. |
| VIN (Pin 2) | Main power input | Accepts 4.5V–45V input; requires local 1µF ceramic bypass capacitor to GND for stability and EMI reduction. |
| ISET (Pin 3) | Peak current programming | Sources 1µA; resistor to GND sets peak inductor current (25–115mA); floating = max, shorted = min. |
| SS (Pin 4) | Soft-start control | Sources 5µA; external capacitor to GND extends startup ramp beyond internal 0.75ms default. |
| RUN (Pin 5) | Enable/disable control | Logic-high (>1.21V) enables regulation; <0.7V forces shutdown (3µA IQ); hysteresis improves noise immunity. |
| VOUT/VFB (Pin 6) | Output voltage sense | Internally connected to 3.3V output; no external divider needed for fixed-output version. |
| HYST (Pin 7) | Run hysteresis open-drain output | Pulled low when RUN <1.2V; can drive external resistor to RUN for adjustable hysteresis. |
| GND (Pin 8 + Exposed Pad Pin 9) | Power and signal ground | Common return for all circuits; exposed pad is mandatory GND connection for thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| No compensation required | Internal control loop eliminates need for external compensation network - reduces BOM count and layout sensitivity. |
| Low dropout operation | 100% duty cycle capability - maintains regulation even when VIN approaches VOUT (e.g., 3.6V → 3.3V). |
| Only three external components | Inductor, input capacitor, output capacitor - minimal bill-of-materials for fixed-output configuration. |
| Internal overvoltage monitor | Withstands 60V input surges - protects downstream circuitry without external TVS or clamping diodes. |
| Precise RUN threshold | 1.21V rising / 1.10V falling with 110mV hysteresis - enables clean, repeatable power sequencing in multi-rail systems. |
Applications
| Industrial Control Supplies | Portable Instruments |
|---|---|
Use Scenario: Powering 4–20mA transmitter circuitry in process automation field devices operating from 24V loop supplies or local batteries. IC Role / Device Role / Timing Role: Primary 3.3V regulator supplying analog front-end, ADC, and microcontroller in isolated or non-isolated transmitters. Use Value: 12µA quiescent current extends battery life in wireless sensor nodes; 45V max input accommodates 24V industrial bus transients. | Use Scenario: Regulating power for handheld multimeters, gas detectors, and portable data loggers powered by single-cell Li-ion or alkaline batteries. IC Role / Device Role / Timing Role: Efficient step-down converter converting variable battery voltage (4.5V–45V system rail) to stable 3.3V for MCU and display. Use Value: Burst Mode® operation sustains >85% efficiency down to 100µA load; DFN package enables ultra-thin device profiles. |
| Battery-Operated Devices | Automotive Power Systems |
Use Scenario: Supplying low-power memory, real-time clocks, and wake-up controllers in always-on IoT edge nodes with coin-cell or small LiFePO₄ batteries. IC Role / Device Role / Timing Role: Standby regulator maintaining critical subsystems during deep sleep, enabled via RUN pin control. Use Value: 3µA shutdown current minimizes battery drain; precise RUN threshold enables controlled wake-up from vehicle CAN/LIN bus signals. | Use Scenario: Generating 3.3V bias for infotainment microcontrollers, body control modules, or ADAS sensors from 12V vehicle battery with load-dump transients. IC Role / Device Role / Timing Role: Robust primary DC/DC stage tolerant of ISO 7637-2 pulse 5a (60V/100ms) without external protection. Use Value: Integrated 60V surge tolerance and UVLO/OVLO eliminate discrete protection components; MSOP/DD footprint fits tight automotive PCB constraints. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3642EMS8E-3.3#TRPBF | Same silicon, 8-lead MSOP package (4.9mm × 3mm) with higher θJA (40°C/W vs 43°C/W); identical electrical specs. | Preferred where manual assembly or thermal relief via larger pad area is prioritized over board area. | Select for prototyping or lower-volume production where MSOP handling and rework ease outweigh DFN density benefits. |
| TPS62130ARGTR | 3–17V input, 3.3V fixed, 3A output; higher current but narrower input range and 17µA IQ; no 60V surge tolerance. | Suitable for consumer-grade 5V/12V systems without industrial transients; not rated for 45V continuous or 60V surges. | Choose only if input stays within 3–17V and surge immunity is not required; avoid in automotive or industrial 24V+ applications. |
Compared with LTC3642EMS8E-3.3#TRPBF, the LTC3642EDD-3.3#TRPBF saves 35% board area and offers slightly better thermal resistance to case (θJC = 3°C/W). Versus TPS62130ARGTR, it trades off maximum current for superior input voltage range, surge resilience, and ultra-low IQ - making it uniquely suited for rugged, low-power, high-input applications.
Availability
LTC3642EDD-3.3#TRPBF is available at Aetrix Electronics and suitable for industrial control supplies, portable instruments, and battery-operated devices requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LTC3642EDD-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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LTC portfolio.
The LTC3642 series was designed as a high-input-voltage, ultra-low-quiescent-current synchronous buck regulator targeting space- and power-constrained industrial, automotive, and portable applications where reliability under voltage transients is critical.
FAQ
What is the maximum input voltage the LTC3642EDD-3.3#TRPBF can withstand continuously and during transients?
The LTC3642EDD-3.3#TRPBF operates continuously from 4.5V to 45V input. Its absolute maximum rating is 60V, and the internal overvoltage lockout activates at ~47V to disable switching - allowing safe exposure to 60V transients per ISO 7637-2 Pulse 5a without damage or latch-up. This makes the LTC3642EDD-3.3#TRPBF suitable for automotive and industrial environments with unregulated or noisy supplies.
Does the LTC3642EDD-3.3#TRPBF require external feedback resistors to set the 3.3V output?
No. The LTC3642EDD-3.3#TRPBF is a fixed-output variant: Pin 6 (VOUT/VFB) is internally connected to the regulated 3.3V output, eliminating the need for external resistive dividers. This simplifies design, improves accuracy (±1.2% over temperature), and reduces component count versus adjustable versions like the LTC3642EDD-ADJ.
How does the programmable peak current limit on the LTC3642EDD-3.3#TRPBF affect efficiency and component selection?
The ISET pin on the LTC3642EDD-3.3#TRPBF sources 1µA; connecting a resistor to GND sets peak inductor current from 25mA to 115mA. Lower peak current enables smaller inductors and capacitors, reducing board area and input ripple - ideal for low-load applications. Efficiency peaks near 10–20mA load when ISET is optimized; the LTC3642EDD-3.3#TRPBF maintains >85% efficiency from 100µA to 50mA with proper ISET tuning.
Can the LTC3642EDD-3.3#TRPBF be used in shutdown mode to achieve ultra-low system standby current?
Yes. Driving the RUN pin below 0.7V places the LTC3642EDD-3.3#TRPBF into shutdown mode, reducing total supply current to just 3µA - significantly lower than its 12µA Burst Mode® quiescent current. This enables multi-year battery life in always-on monitoring systems. The HYST pin provides open-drain status signaling for system-level power sequencing control.
What thermal considerations apply to the LTC3642EDD-3.3#TRPBF in its 3mm × 3mm DFN package?
The LTC3642EDD-3.3#TRPBF uses a thermally enhanced DFN with an exposed GND pad (Pin 9). For reliable operation at full 50mA load, the exposed pad must be soldered to a minimum 100mm² copper pour on the PCB. Thermal resistance is θJA = 43°C/W and θJC = 3°C/W - meaning junction-to-case conduction dominates cooling. Without adequate pad area or airflow, power dissipation above ~0.5W may exceed 125°C junction limit.
LTC3642EDD-3.3#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-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):
- 4.5V
- Voltage - Input (Max):
- 45V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 50mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (3x3)
LTC3642EDD-3.3#TRPBF FAQ
1.How can I place an order for LTC3642EDD-3.3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3642EDD-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 LTC3642EDD-3.3#TRPBF reliable?
The price and inventory of LTC3642EDD-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 LTC3642EDD-3.3#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3642EDD-3.3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3642EDD-3.3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3642EDD-3.3#TRPBF?
LTC3642EDD-3.3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3642EDD-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 LTC3642EDD-3.3#TRPBF?
For technical support, including LTC3642EDD-3.3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3642EDD-3.3#TRPBF requirements.
6.How does Aetrix verify that LTC3642EDD-3.3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3642EDD-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 LTC3642EDD-3.3#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3642EDD-3.3#TRPBF?
All LTC3642EDD-3.3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3642EDD-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 LTC3642EDD-3.3#TRPBF part is unused and in its original packaging.
Return procedure for LTC3642EDD-3.3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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