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Analog Devices Inc. LTC3642IDD-3.3#PBF
- Part No.:
- LTC3642IDD-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3642IDD-3.3#PBF.pdf
- Description:
- IC REG BUCK 3.3V 50MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,958
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Product details
Overview
LTC3642IDD-3.3#PBF from Analog Devices (formerly Linear Technology) is a high-voltage, synchronous step-down DC/DC converter with integrated 3.3V fixed output, internal high-side and low-side MOSFETs, 4.5V–45V input range, 50mA output capability, and 12µA no-load quiescent current-designed for industrial control supplies and battery-operated devices requiring robust input surge tolerance.
For engineers reviewing the LTC3642IDD-3.3#PBF datasheet, LTC3642IDD-3.3#PBF pinout, LTC3642IDD-3.3#PBF application, or LTC3642IDD-3.3#PBF equivalent, key selection considerations include its programmable peak current limit (25–115mA), precise RUN pin threshold (1.21V rising), 0.8V feedback reference, Burst Mode® operation for ultra-low IQ, and compatibility with 3mm × 3mm DFN thermal performance (θJA = 43°C/W).
Technical Context
The LTC3642IDD-3.3#PBF implements a hysteretic Burst Mode® control architecture with an internal 0.8V feedback reference and 5mV comparator hysteresis, enabling high efficiency across 0.1mA–50mA loads. Its peak current-limited switching uses a user-programmable ISET pin (1µA sourced) to set trip thresholds between 25mA and 115mA, directly determining maximum average output current (up to 55mA).
Startup is managed by 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 (5µA sourced). Input protection includes undervoltage lockout (UVLO: 3.75V–4.50V) and overvoltage lockout (OVLO: 47V–52V), sustaining 60V transients without damage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 45V - supports wide industrial and automotive supply rails; tolerates 60V transients without shutdown. |
| Output Voltage | 3.3V ±1.2% - factory-trimmed fixed output; no external resistors required. |
| Max Output Current | 50mA - sustained load capability; peak inductor current programmable up to 115mA. |
| No-Load Quiescent Current | 12µA - enables multi-year battery life in always-on sensor nodes and portable instruments. |
| Feedback Reference | 0.800V ±1% - precise internal reference enabling accurate output regulation and stable loop behavior. |
| Run Pin Threshold | 1.21V (rising), 1.10V (falling) - tightly controlled enable/disable point for reliable power sequencing. |
| Package Thermal Resistance | θJA = 43°C/W - 3mm × 3mm DFN with exposed pad ensures effective heat dissipation at full load. |
Pinout & Package
Package: 8-lead (3mm × 3mm) plastic DFN with exposed GND pad (Pin 9), rated for –40°C to 125°C junction temperature. Exposed pad must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch node | Connection to inductor; ties drains of internal P-channel high-side and N-channel low-side MOSFETs. |
| VIN (Pin 2) | Main input supply | Accepts 4.5V–45V; requires local 1µF ceramic bypass to GND for stability and EMI suppression. |
| ISET (Pin 3) | Peak current programming | 1µA current source; resistor to GND sets peak current limit (25–115mA); floating = max, shorted = min. |
| SS (Pin 4) | Soft-start control | 5µA current source; external capacitor sets ramp time; floating defaults to 0.75ms internal soft-start. |
| RUN (Pin 5) | Enable/disable control | Logic-level input: >1.21V enables operation; <0.7V forces shutdown (3µA IQ); hysteresis improves noise immunity. |
| VOUT/VFB (Pin 6) | Output voltage sense | Direct connection to 3.3V output; internal 0.8V reference compares feedback for regulation. |
| HYST (Pin 7) | Run hysteresis open-drain | Pulled low when RUN < 1.2V; used externally to increase RUN pin hysteresis via resistor divider. |
| GND (Pins 8 & 9) | Power and signal ground | Pins 8 and 9 (exposed pad) are internally connected; pad must be soldered to PCB ground for thermal performance. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® operation | Maintains 12µA no-load IQ while delivering regulated 3.3V output - critical for battery longevity in remote sensors. |
| Integrated power switches | Internal high-side P-MOSFET and low-side N-MOSFET eliminate external FETs and gate drivers - reduces BOM count and layout area. |
| Programmable peak current limit | Adjustable 25–115mA via single resistor on ISET - enables optimization of inductor size, ripple, and efficiency for specific load profiles. |
| Precision RUN pin with hysteresis | 1.21V enable threshold with 110mV hysteresis - ensures clean, bounce-free power-up and brownout recovery in noisy environments. |
| 60V transient tolerance | Withstands 60V input surges without latch-up or damage - suitable for automotive load-dump and industrial field wiring. |
Applications
| Industrial Control Supplies | Portable Instruments |
|---|---|
Use Scenario: Powering 4–20mA current-loop transmitters and PLC I/O modules in factory automation systems with unregulated 24V DC rails. IC Role / Device Role / Timing Role: Primary 3.3V regulator supplying microcontroller, ADC, and analog front-end circuitry. Use Value: UVLO/OVLO protection prevents malfunction during line transients; low IQ extends uptime in battery-backed controllers. |
Use Scenario: Providing stable 3.3V rail for handheld multimeters, gas detectors, and environmental monitors powered by two AA cells. IC Role / Device Role / Timing Role: Main system regulator enabling deep-sleep modes between measurements. Use Value: 12µA quiescent current enables >5-year battery life; 4.5V minimum VIN supports operation down to ~2.25V/cell. |
| Battery-Operated Devices | Automotive Power Systems |
Use Scenario: Regulating power for wireless sensor nodes (LoRaWAN, NB-IoT) deployed in remote infrastructure monitoring. IC Role / Device Role / Timing Role: Efficient step-down converter interfacing LiSOCl₂ primary batteries (3.6V) or alkaline stacks (6–9V) to 3.3V logic. Use Value: Burst Mode® maintains >85% efficiency at 100µA loads; adjustable peak current minimizes inductor size for compact designs. |
Use Scenario: Supplying 3.3V to infotainment MCU peripherals and CAN transceivers in 12V vehicle subsystems subject to load dump. IC Role / Device Role / Timing Role: Secondary regulator downstream of main 5V buck, hardened against ISO 7637-2 pulse 5a (60V/100ms). Use Value: 60V absolute max rating and internal OVLO ensure continuous operation during alternator load dump events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage, low-IQ step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62130ARGTR | 3–17V input, 3.3V fixed, 3A output, 17µA IQ - lacks 60V surge tolerance and programmable peak current. | Targeted at higher-current consumer electronics; unsuitable for 24V industrial or automotive inputs. | Select only if input stays ≤17V and >50mA output is required; verify external protection for transients. |
| MAX17536ATP+T | 4.5–60V input, 3.3V adjustable, 100mA output, 20µA IQ - requires external feedback resistors and has higher IQ. | Designed for wider VIN and higher current; less optimized for ultra-low-power battery use cases. | Prefer when >50mA load or tighter input surge margin (>60V) is needed; accept added BOM complexity. |
Compared with TPS62130ARGTR and MAX17536ATP+T, the LTC3642IDD-3.3#PBF uniquely combines 4.5–45V operation, 12µA IQ, fixed 3.3V output, and 60V transient survival in a 3mm × 3mm DFN-making it optimal for space-constrained, long-life industrial and portable systems where simplicity and ruggedness are prioritized over raw current capacity.
Availability
LTC3642IDD-3.3#PBF is available at Aetrix Electronics and suitable for industrial control supplies, portable instruments, battery-operated devices, and automotive power systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC3642IDD-3.3#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3642 product line delivers high-voltage, low-quiescent-current step-down converters for harsh-environment applications-designed specifically for reliability under wide-input, transient-prone, and battery-sensitive conditions.
FAQ
What is the maximum input voltage the LTC3642IDD-3.3#PBF can withstand without damage?
The LTC3642IDD-3.3#PBF has an absolute maximum input rating of 60V and includes internal overvoltage lockout (OVLO) that disables switching above 47V–52V. It safely sustains 60V transients-such as automotive load dump-without latch-up or degradation, provided the duration remains within datasheet limits. This makes the LTC3642IDD-3.3#PBF suitable for 24V industrial and 12V automotive systems with unfiltered inputs.
Does the LTC3642IDD-3.3#PBF require external compensation components?
No, the LTC3642IDD-3.3#PBF uses a hysteretic Burst Mode® control architecture with internal compensation-no external capacitors or resistors are needed for loop stability. Only three external components (inductor, input capacitor, output capacitor) are required for basic operation. This simplifies design, reduces footprint, and eliminates compensation tuning effort for the LTC3642IDD-3.3#PBF.
Can the output voltage of the LTC3642IDD-3.3#PBF be adjusted to a value other than 3.3V?
No-the LTC3642IDD-3.3#PBF is a factory-trimmed fixed-output variant; its VOUT/VFB pin is internally connected to a precision 3.3V regulation circuit and cannot be reconfigured. For adjustable output, select the LTC3642IDD-ADJ version and use an external resistor divider per the 0.8V feedback reference. The LTC3642IDD-3.3#PBF delivers exactly 3.3V ±1.2% across temperature and load.
How does the ISET pin affect efficiency and component selection in the LTC3642IDD-3.3#PBF?
The ISET pin on the LTC3642IDD-3.3#PBF programs the peak inductor current from 25mA to 115mA via a resistor to GND. Lower peak current reduces required inductor size, input/output capacitance, and RMS losses-improving efficiency at light loads (<10mA) and enabling smaller footprints. Higher peak current supports full 50mA output but increases ripple and may require larger magnetics. Efficiency optimization for a given load is achieved by matching ISET setting to actual peak demand in the LTC3642IDD-3.3#PBF.
Is the exposed thermal pad (Pin 9) of the LTC3642IDD-3.3#PBF electrically connected to ground?
Yes-the exposed pad (Pin 9) of the LTC3642IDD-3.3#PBF is internally bonded to GND and must be soldered to a PCB copper pour tied to the system ground plane. This connection is mandatory for both electrical functionality (low-impedance return path) and thermal performance (θJC = 3°C/W). Omitting pad soldering degrades thermal resistance, risks overheating at >30mA loads, and may cause regulation instability in the LTC3642IDD-3.3#PBF.
LTC3642IDD-3.3#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tube
- 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)
LTC3642IDD-3.3#PBF FAQ
1.How can I place an order for LTC3642IDD-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3642IDD-3.3#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 LTC3642IDD-3.3#PBF reliable?
The price and inventory of LTC3642IDD-3.3#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3642IDD-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LTC3642IDD-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3642IDD-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3642IDD-3.3#PBF?
LTC3642IDD-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3642IDD-3.3#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 LTC3642IDD-3.3#PBF?
For technical support, including LTC3642IDD-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3642IDD-3.3#PBF requirements.
6.How does Aetrix verify that LTC3642IDD-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3642IDD-3.3#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 LTC3642IDD-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LTC3642IDD-3.3#PBF?
All LTC3642IDD-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3642IDD-3.3#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 LTC3642IDD-3.3#PBF part is unused and in its original packaging.
Return procedure for LTC3642IDD-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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