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Analog Devices Inc. LTC3642IDD-3.3#TRPBF
- Part No.:
- LTC3642IDD-3.3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3642IDD-3.3#TRPBF.pdf
- Description:
- IC REG BUCK 3.3V 50MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,852
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Product details
Overview
LTC3642IDD-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. It operates from 4.5V to 45V input, maintains regulation with only 12µA quiescent current in Burst Mode®, and features programmable peak current limit (25–115mA) for efficiency optimization in low-power industrial sensors and battery-backed systems.
For engineers reviewing the LTC3642IDD-3.3#TRPBF datasheet, LTC3642IDD-3.3#TRPBF pinout, LTC3642IDD-3.3#TRPBF application, or LTC3642IDD-3.3#TRPBF equivalent, key selection considerations include its 3mm × 3mm DFN package with exposed thermal pad, 0.8V internal feedback reference, precise RUN pin threshold (1.21V rising), and tolerance of 60V input transients-critical for automotive and industrial power rail conditioning.
Technical Context
The LTC3642IDD-3.3#TRPBF uses a hysteretic Burst Mode® control architecture with an internal 0.8V feedback comparator and 5mV hysteresis, enabling automatic transition between active switching and ultra-low-quiescent sleep cycles. Its peak current-limited operation-set via ISET pin resistor or open/ground configuration-directly governs maximum inductor ramp rate and average output capability (≤50mA).
Startup is controlled by a precision RUN pin comparator (1.21V enable threshold, 110mV hysteresis) paired with internal 0.75ms soft-start and optional external SS capacitor ramping. Input protection includes undervoltage lockout (4.35V max falling) and overvoltage lockout (47V min rising), allowing safe operation up to 60V transient surges without external clamping.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 45V - supports wide-range industrial and automotive supplies; tolerates 60V transients without damage |
| Output Voltage | Fixed 3.3V ±1.2% - guaranteed over –40°C to 125°C junction temperature, no external feedback divider required |
| Max Output Current | 50mA - determined by 100mA peak inductor current limit (2× average due to hysteretic control) |
| Quiescent Current | 12µA typical in regulation - enables multi-year battery life in always-on sensor nodes |
| Feedback Reference | 0.800V ±1% - sets output accuracy and enables precise external adjustment in adjustable variants |
| Switch On-Resistance | Top: 3.0Ω, Bottom: 1.5Ω - defines conduction loss at light-to-moderate loads; thermally enhanced DFN minimizes θJA (43°C/W) |
| Operating Temperature | –40°C to 125°C - qualified for under-hood automotive and industrial control environments |
Pinout & Package
Package: 8-lead (3mm × 3mm) plastic DFN with exposed thermal pad (Pin 9), RoHS-compliant, moisture-sensitive level 3. 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 point for external inductor; carries high di/dt switching waveform; requires tight layout to minimize EMI |
| VIN (Pin 2) | Main input supply | Accepts 4.5V–45V; requires local 1µF ceramic bypass to GND (Pin 8/9) for stability and transient response |
| ISET (Pin 3) | Peak current programming | Sources 1µA; resistor to GND sets peak current (25–115mA); floating = 115mA, grounded = 25mA |
| 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 | 1.21V rising threshold enables operation; <0.7V forces shutdown (3µA IQ); HYST pin provides hysteresis extension |
| VOUT/VFB (Pin 6) | Output voltage sense | Internally connected to 3.3V output in fixed version; serves as feedback input in adjustable variants |
| HYST (Pin 7) | Open-drain hysteresis output | Pulled low when RUN <1.2V; used with external resistor divider to increase effective RUN hysteresis |
| GND (Pin 8 & Pin 9) | Power and signal ground | Pin 8 is signal GND; Pin 9 is exposed thermal pad-must be soldered to PCB ground plane |
Key Features
| Feature | Design Value |
|---|---|
| No compensation required | Internal hysteretic control eliminates need for external loop compensation components, reducing BOM count and layout sensitivity |
| Low dropout operation | 100% duty cycle capability enables regulation down to VIN ≈ VOUT + (ILOAD × RDS(ON)), critical for battery end-of-life operation |
| Internal overvoltage monitor | Shuts down switching above 47V (min), protecting downstream circuitry during load dump or surge events up to 60V |
| Adjustable peak current limit | Enables optimization of inductor size, input/output capacitor values, and efficiency across 10:1 load range without changing IC |
| Precise RUN pin threshold | 1.21V enable threshold with 110mV hysteresis ensures clean, bounce-free power sequencing in noisy industrial environments |
Applications
| Industrial Sensor Nodes | Automotive Body Control Modules |
|---|---|
Use Scenario: Powering low-power MEMS accelerometers and temperature sensors in factory-floor wireless IoT nodes with 12V or 24V supply rails. IC Role / Device Role / Timing Role: Primary 3.3V regulator supplying microcontroller, RF transceiver, and analog front-end; operates in Burst Mode® during sleep intervals. Use Value: 12µA quiescent current extends coin-cell or supercapacitor backup runtime to >5 years; 45V input rating accommodates unregulated 24V industrial bus transients. |
Use Scenario: Providing stable 3.3V bias to LIN transceivers and door module MCUs in passenger compartment electronics. IC Role / Device Role / Timing Role: Secondary regulator deriving 3.3V from vehicle battery (9V–16V nominal) while surviving 60V load-dump pulses per ISO 7637-2. Use Value: Integrated 60V-tolerant input protection eliminates need for external TVS diode; DFN package enables compact placement near load points. |
| Portable Medical Instruments | Distributed Power Systems |
Use Scenario: Regulating power for handheld pulse oximeters and glucose meters using single Li-ion or dual AA cells. IC Role / Device Role / Timing Role: Step-down converter maintaining 3.3V output across full battery discharge (3.0V–4.2V), leveraging low-IQ and 100% duty cycle capability. Use Value: 12µA sleep current minimizes standby drain; programmable peak current allows use of miniature 47µH inductors to meet size constraints. |
Use Scenario: Local point-of-load regulation in telecom line cards where 48V backplane supplies multiple isolated 3.3V domains. IC Role / Device Role / Timing Role: Non-isolated buck converter generating 3.3V for FPGA I/O banks and SerDes power, operating from intermediate 12V rail. Use Value: Wide 4.5V–45V input range supports flexible intermediate bus architectures; thermal DFN package simplifies heatsinking in dense board layouts. |
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 | Lower input range (3V–17V), higher IQ (19µA), 3A output; uses voltage-mode PWM, not Burst Mode® | Not suitable for 24V+ inputs or ultra-low-power battery apps; better for higher-current, noise-sensitive systems requiring fixed-frequency operation | Select only if input <17V and >100mA load required; incompatible with 45V industrial rails |
| MAX17502ATP+T | Wider input (4.5V–60V), higher output (300mA), 13µA IQ; requires external compensation, larger 16-pin TQFN | Targeted at higher-power industrial PLCs; lacks integrated hysteresis and precise RUN threshold of LTC3642IDD-3.3#TRPBF | Choose when >100mA needed and board space allows larger package; adds design complexity with compensation network |
Compared with TPS62130ARGTR and MAX17502ATP+T, the LTC3642IDD-3.3#TRPBF uniquely combines 45V input, 12µA IQ, fixed 3.3V output, and zero-compensation operation in a 3mm × 3mm DFN-making it optimal for space-constrained, long-life, high-input-voltage sensor and control applications where simplicity and ultra-low standby power are mandatory.
Availability
LTC3642IDD-3.3#TRPBF is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body electronics, portable medical instruments, and distributed power systems requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LTC3642IDD-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 its legacy of high-performance analog and power management ICs with rigorous automotive and industrial qualification standards.
The LTC3642 product line was designed specifically for high-input-voltage, ultra-low-quiescent-current DC/DC conversion in harsh environments-targeting battery-backed instrumentation, automotive subsystems, and industrial IoT edge nodes where reliability and efficiency at microamp loads are critical.
FAQ
What is the absolute maximum input voltage rating for the LTC3642IDD-3.3#TRPBF?
The LTC3642IDD-3.3#TRPBF has an absolute maximum VIN rating of 60V, meaning it can safely withstand transient surges up to this level without damage-even though continuous operation is limited to 4.5V–45V. This 60V rating is verified per Absolute Maximum Ratings table and enables robust deployment in automotive load-dump and industrial surge environments without external clamping components.
Does the LTC3642IDD-3.3#TRPBF require external feedback resistors to set the 3.3V output?
No, the LTC3642IDD-3.3#TRPBF is a fixed-output variant with internal feedback divider; VOUT/VFB (Pin 6) connects directly to the regulated 3.3V rail. External resistors are only required for the adjustable version (LTC3642IDD-ADJ). This eliminates component count, improves accuracy, and avoids leakage-induced errors common with high-value external dividers.
How does the ISET pin affect output current capability in the LTC3642IDD-3.3#TRPBF?
The ISET pin on the LTC3642IDD-3.3#TRPBF programs the peak inductor current limit between 25mA (ISET = GND) and 115mA (ISET = floating), directly determining maximum average output current (≤50mA). Since average current ≈ 0.5 × peak current in Burst Mode®, setting ISET adjusts both efficiency vs. load curve and minimum inductor value-enabling optimization for specific power and size requirements.
Can the LTC3642IDD-3.3#TRPBF operate with 100% duty cycle, and why is that important?
Yes, the LTC3642IDD-3.3#TRPBF supports 100% duty cycle operation, allowing regulation when VIN approaches VOUT (e.g., 3.6V input → 3.3V output). This is essential for battery-powered systems nearing end-of-life, where input voltage drops below the typical buck converter dropout margin. The feature relies on low RDS(ON) of internal switches and absence of minimum off-time limitation.
What thermal performance can be expected from the LTC3642IDD-3.3#TRPBF in its DFN package?
The LTC3642IDD-3.3#TRPBF in the 3mm × 3mm DFN package has θJA = 43°C/W (JEDEC standard PCB) and θJC = 3°C/W. With the exposed pad (Pin 9) soldered to a 1-in² copper area, junction-to-ambient rise is ~22°C at 50mA output (assuming 0.5W dissipation). This enables full-rated operation at 125°C ambient without derating in properly laid-out industrial designs.
LTC3642IDD-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)
LTC3642IDD-3.3#TRPBF FAQ
1.How can I place an order for LTC3642IDD-3.3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3642IDD-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 LTC3642IDD-3.3#TRPBF reliable?
The price and inventory of LTC3642IDD-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 LTC3642IDD-3.3#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3642IDD-3.3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3642IDD-3.3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3642IDD-3.3#TRPBF?
LTC3642IDD-3.3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3642IDD-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 LTC3642IDD-3.3#TRPBF?
For technical support, including LTC3642IDD-3.3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3642IDD-3.3#TRPBF requirements.
6.How does Aetrix verify that LTC3642IDD-3.3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3642IDD-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 LTC3642IDD-3.3#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3642IDD-3.3#TRPBF?
All LTC3642IDD-3.3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3642IDD-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 LTC3642IDD-3.3#TRPBF part is unused and in its original packaging.
Return procedure for LTC3642IDD-3.3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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