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Analog Devices Inc. LTC3642EDD-3.3#PBF
- Part No.:
- LTC3642EDD-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3642EDD-3.3#PBF.pdf
- Description:
- IC REG BUCK 3.3V 50MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,361
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Product details
Overview
LTC3642EDD-3.3#PBF 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 input surge tolerance and ultra-low standby power.
For engineers reviewing the LTC3642EDD-3.3#PBF datasheet, LTC3642EDD-3.3#PBF pinout, LTC3642EDD-3.3#PBF application, or LTC3642EDD-3.3#PBF equivalent, key selection criteria include its 60V transient tolerance, programmable peak current limit (25–115mA), 0.8V feedback reference, internal soft-start, and precise RUN pin threshold with hysteresis - all critical for reliable start-up in wide-input industrial and automotive environments.
Technical Context
The LTC3642EDD-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 load currents from 100µA to 50mA. Its peak current limit is set via external resistor on ISET (25–115mA range), and switching frequency varies dynamically with VIN, VOUT, and inductance - no compensation required.
Start-up is managed by a precise 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 (UVLO: 3.75–4.50V) and overvoltage lockout (OVLO: 47–52V), allowing safe operation through 60V transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 45V - supports wide-range industrial and automotive inputs; tolerates 60V transients without damage. |
| Output Voltage | Fixed 3.3V ±1.2% (3.24V–3.36V) - precision regulation for MCU and sensor rails. |
| Max Output Current | 50mA - sufficient for low-power microcontrollers, sensors, and interface ICs. |
| Quiescent Current | 12µA typical in Burst Mode® - enables multi-year battery life in always-on IoT nodes. |
| Feedback Reference | 0.800V ±1% - enables accurate output setting and stable loop performance with minimal external components. |
| Peak Current Limit | Programmable 25mA to 115mA via ISET resistor - allows optimization of inductor size, ripple, and efficiency for specific load profiles. |
| Soft-Start | Internal 0.75ms + external adjustable via SS pin - prevents input droop and inrush during cold start. |
| Thermal Package | 8-lead 3mm × 3mm DFN with exposed GND pad - θJA = 43°C/W, enabling 50mA operation without heatsink at TA ≤ 85°C. |
Pinout & Package
Package: 8-lead (3mm × 3mm) plastic DFN with exposed thermal pad (Pin 9 = GND), rated for –40°C to 125°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch node | Connects to inductor; carries high di/dt switching current - requires tight layout and Kelvin connection to minimize ringing. |
| VIN (Pin 2) | Main input supply | Accepts 4.5V–45V; must be bypassed with ≥1µF ceramic capacitor directly to GND for stability and EMI control. |
| 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 sets ramp time - overrides internal 0.75ms soft-start when slower. |
| RUN (Pin 5) | Enable/disable control | Active-high logic: >1.21V enables, <1.10V disables; hysteresis ensures clean power sequencing. |
| VOUT/VFB (Pin 6) | Output feedback | Internally connected to 3.3V output; monitors regulation via 0.8V reference - no external divider needed. |
| HYST (Pin 7) | Run hysteresis open-drain output | Pulled low when RUN < 1.2V; can drive external resistor to increase RUN pin hysteresis for noisy supply monitoring. |
| GND (Pins 8 & 9) | Power and thermal ground | Pin 8 = signal GND; Pin 9 = exposed thermal pad - both must be soldered to PCB ground plane for thermal and electrical integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® operation | Maintains 85%+ efficiency down to 100µA load while holding quiescent current at 12µA - eliminates need for external enable sequencing in battery systems. |
| Integrated power switches | Low RON top (3.0Ω) and bottom (1.5Ω) MOSFETs - eliminate external FETs and gate drivers, reducing BOM count and layout complexity. |
| 60V transient tolerance | Withstands 60V surges on VIN without shutdown or latch-up - suitable for 24V/36V industrial buses and automotive load-dump conditions. |
| No compensation required | Stable with standard ceramic input/output capacitors - removes loop compensation design effort and sensitivity to component variation. |
| 100% duty cycle capability | Supports low-dropout operation near VIN ≈ VOUT - maintains regulation even as input decays (e.g., discharging battery). |
| Precise RUN threshold | 1.21V enable with 110mV hysteresis - enables clean, jitter-free power-up in noisy environments without external RC filtering. |
Applications
| Industrial Control Supplies | Portable Instruments |
|---|---|
Use Scenario: Powering 3.3V microcontrollers, analog front-ends, and isolated RS-485 transceivers in PLC I/O modules exposed to 24V rail transients. IC Role / Device Role / Timing Role: Primary 3.3V point-of-load regulator with input surge protection and low-noise output. Use Value: Eliminates need for external TVS and LDO pre-regulator; 60V transient tolerance and 12µA quiescent current extend system uptime and battery life. |
Use Scenario: Supplying 3.3V logic and sensors in handheld multimeters and portable gas detectors powered by two AA cells (up to 3.4V) or 9V batteries. IC Role / Device Role / Timing Role: Wide-input buck converter enabling direct battery-to-3.3V conversion without intermediate stages. Use Value: 4.5V minimum input accommodates 9V battery discharge curve; 12µA sleep current extends shelf life beyond 5 years. |
| Battery-Operated Devices | Automotive Power Systems |
Use Scenario: Regulating 3.3V for BLE/Wi-Fi SoCs and environmental sensors in asset trackers using Li-SOCl₂ primary cells (3.6V nominal, up to 3.9V). IC Role / Device Role / Timing Role: Efficient step-down regulator with programmable peak current to match pulsed RF load profiles. Use Value: Adjustable ISET allows optimizing inductor size and ripple for bursty wireless transmission, reducing average power consumption by 30% vs fixed-current designs. |
Use Scenario: Providing 3.3V bias for CAN transceivers and microcontrollers in body electronics modules connected to 12V vehicle bus. IC Role / Device Role / Timing Role: Load-dump tolerant DC/DC converter replacing linear regulators in space-constrained modules. Use Value: Withstands ISO 7637-2 Pulse 5a (75V/100ms) without external clamping; DFN package fits tight PCB footprints behind connectors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3643EDD-3.3#PBF | Higher 100mA output current, same 4.5V–45V input, identical pinout and features - but larger 3mm × 4mm DFN package. | Required where sustained >50mA loads exist (e.g., active sensors + RF), not suitable for strict 3mm × 3mm area constraints. | Select LT3643EDD-3.3#PBF only if higher output current is needed; otherwise LTC3642EDD-3.3#PBF offers better size/power density. |
| TPS62130ARGTR | Lower 3.6V max input, 3A output, different control scheme (PWM), no 60V transient tolerance, 0.6V reference - not pin-compatible. | Applicable only in low-voltage, high-current consumer applications (e.g., USB-powered devices); unsuitable for industrial 24V/36V rails. | TPS62130ARGTR is not a functional substitute for LTC3642EDD-3.3#PBF in high-input or surge-prone environments - use only in validated low-voltage designs. |
Compared with LT3643EDD-3.3#PBF, LTC3642EDD-3.3#PBF provides identical functionality in a smaller footprint and lower quiescent current, making it optimal for space- and battery-limited designs; compared with TPS62130ARGTR, it delivers ruggedized high-input operation and transient immunity essential for industrial and automotive use - neither alternative matches its combination of 3mm × 3mm size, 60V tolerance, and 12µA IQ.
Availability
LTC3642EDD-3.3#PBF 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 traceable sourcing.
Supply support for LTC3642EDD-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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LTC portfolio.
The LTC3642 product line was designed for high-input-voltage, low-quiescent-current step-down regulation in harsh environments - targeting industrial, automotive, and battery-powered applications where reliability, surge immunity, and standby efficiency are critical.
FAQ
What is the maximum input voltage the LTC3642EDD-3.3#PBF can withstand without damage?
The LTC3642EDD-3.3#PBF has an absolute maximum VIN rating of 60V and includes internal overvoltage lockout that disables switching above 47–52V. This allows the device to safely survive 60V transients - such as automotive load dump or industrial surge events - without latch-up or degradation, provided the duration remains within datasheet limits (e.g., ISO 7637-2 Pulse 5a compliant).
Does the LTC3642EDD-3.3#PBF require external compensation components?
No, the LTC3642EDD-3.3#PBF uses a hysteretic Burst Mode® architecture that is inherently stable and requires no external compensation network. It operates reliably with standard ceramic input and output capacitors - simplifying design, reducing BOM count, and eliminating loop stability validation effort typically needed for voltage-mode or current-mode controllers.
How is the output voltage accuracy specified for the LTC3642EDD-3.3#PBF?
The LTC3642EDD-3.3#PBF guarantees a fixed 3.3V output with ±1.2% tolerance over temperature and line - meaning the actual output remains between 3.24V and 3.36V under all operating conditions. This accuracy derives from a precision 0.800V ±1% internal feedback reference and trimmed internal resistive divider, eliminating drift from external component tolerances.
Can the LTC3642EDD-3.3#PBF operate with 100% duty cycle?
Yes, the LTC3642EDD-3.3#PBF supports 100% duty cycle operation, enabling regulation even when VIN approaches VOUT (e.g., 3.6V input to 3.3V output). This feature is critical for battery-powered systems where input voltage decays over time - ensuring continuous regulation without dropout until VIN falls below the 4.5V UVLO threshold.
What is the purpose of the HYST pin on the LTC3642EDD-3.3#PBF?
The HYST pin on the LTC3642EDD-3.3#PBF is an open-drain output that pulls low when the RUN pin voltage is below 1.2V, signaling disabled state. It can be used to increase effective RUN pin hysteresis - for example, by connecting a resistor from HYST to RUN - improving noise immunity when monitoring noisy input rails via resistive dividers.
LTC3642EDD-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)
LTC3642EDD-3.3#PBF FAQ
1.How can I place an order for LTC3642EDD-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3642EDD-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 LTC3642EDD-3.3#PBF reliable?
The price and inventory of LTC3642EDD-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 LTC3642EDD-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LTC3642EDD-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3642EDD-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3642EDD-3.3#PBF?
LTC3642EDD-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3642EDD-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 LTC3642EDD-3.3#PBF?
For technical support, including LTC3642EDD-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3642EDD-3.3#PBF requirements.
6.How does Aetrix verify that LTC3642EDD-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3642EDD-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 LTC3642EDD-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LTC3642EDD-3.3#PBF?
All LTC3642EDD-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3642EDD-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 LTC3642EDD-3.3#PBF part is unused and in its original packaging.
Return procedure for LTC3642EDD-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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