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Analog Devices Inc. LTC3642EDD#PBF
- Part No.:
- LTC3642EDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3642EDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 50MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,089
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Product details
Overview
LTC3642EDD#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 from a 4.5V–45V input. It operates in Burst Mode® with 12µA no-load quiescent current, features programmable peak current limit (25–115mA), and uses a precise 0.8V feedback reference for stable regulation in industrial control supplies and battery-operated devices.
For engineers reviewing the LTC3642EDD#PBF datasheet, LTC3642EDD#PBF pinout, LTC3642EDD#PBF application, or LTC3642EDD#PBF equivalent, key selection considerations include its 60V transient tolerance, internal soft-start, RUN pin hysteresis control, adjustable peak current programming via ISET, and compatibility with fixed 3.3V/5V or adjustable output configurations using minimal external components.
Technical Context
The LTC3642EDD#PBF implements a hysteretic Burst Mode® control architecture with an internal 0.8V feedback comparator and 5mV hysteresis, enabling ultra-low quiescent current operation while maintaining regulation across load currents from 0.1mA to 50mA. Its peak current-limited switching uses a programmable threshold (25–115mA) set by an external resistor on the ISET pin, directly determining maximum average output current (up to 55mA).
Startup is managed by a precise RUN pin comparator (1.21V rising threshold, 110mV hysteresis) and dual soft-start capability-internal 0.75ms ramp plus optional external capacitor on SS pin-ensuring controlled voltage rise and inductor current ramping. Input protection includes undervoltage lockout (3.75–4.5V range) and overvoltage lockout (47–52V range), allowing safe operation during 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 Current | Up to 50mA - sufficient for powering microcontrollers, sensors, and analog circuitry in low-power systems. |
| Quiescent Current | 12µA typical at no load - enables multi-year battery life in always-on portable instrumentation. |
| Feedback Reference | 0.800V ±8mV - precision reference enables accurate output regulation across temperature and line variations. |
| Peak Current Limit | Programmable 25mA to 115mA via ISET resistor - allows optimization of efficiency, component size, and ripple for specific load profiles. |
| Switch On-Resistance | Top switch: 3.0Ω, bottom switch: 1.5Ω - low RDS(on) minimizes conduction losses at light-to-moderate loads. |
| Soft-Start Time | Internal 0.75ms default; externally adjustable via SS pin capacitor - prevents input supply droop during power-up. |
Pinout & Package
The LTC3642EDD#PBF is housed in an 8-lead, 3mm × 3mm plastic DFN package with exposed thermal pad (Pin 9 = GND), optimized for compact layout and efficient heat dissipation in space-constrained applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch node | Connects to inductor; carries high di/dt switching waveform - requires short, low-inductance PCB trace to minimize EMI. |
| VIN (Pin 2) | Main input supply | Accepts 4.5V–45V input; must be bypassed with ceramic capacitor to GND for stability and transient response. |
| ISET (Pin 3) | Peak current programming | Sources 1µA; resistor to GND sets peak inductor current (25–115mA), directly scaling max output current and ripple. |
| SS (Pin 4) | Soft-start control | Sources 5µA; external capacitor sets output voltage ramp time - overrides internal 0.75ms soft-start if slower. |
| 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 feedback | Fixed-output versions connect directly to VOUT; adjustable versions use resistive divider to sense 0.8V reference. |
| HYST (Pin 7) | Run hysteresis logic output | Open-drain output pulled low when RUN <1.2V - used to increase effective RUN hysteresis in divider-based monitoring circuits. |
| GND (Pins 8 & 9) | Power and thermal ground | Pins 8 and 9 (exposed pad) must be soldered to PCB ground plane - critical for thermal performance and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® operation | Maintains regulation at light loads with only 12µA IQ - eliminates need for external enable sequencing in energy-harvesting systems. |
| Integrated power switches | Internal P-channel high-side and N-channel low-side MOSFETs - eliminates external FETs and gate drivers, reducing BOM count and layout complexity. |
| Adjustable peak current limit | 25–115mA via single ISET resistor - enables trade-off between efficiency, inductor size, and output ripple without changing topology. |
| Precise RUN pin threshold | 1.21V rising / 1.10V falling with 110mV hysteresis - ensures clean, bounce-free enable/disable transitions in noisy industrial environments. |
| No compensation required | Internally compensated control loop - eliminates external compensation network, simplifying design and improving production yield. |
Applications
| 4–20mA Current Loops | Industrial Control Supplies |
|---|---|
Use Scenario: Powering loop-powered transmitters in process automation where supply is derived from 4–20mA loop voltage. IC Role / Device Role / Timing Role: Step-down regulator providing stable 3.3V or 5V rail from variable loop voltage (typically 12–36V). Use Value: 12µA quiescent current ensures minimal impact on loop compliance voltage; 60V surge tolerance protects against field wiring transients. |
Use Scenario: Local regulation for PLC I/O modules, sensor interfaces, and isolated communication peripherals in factory automation. IC Role / Device Role / Timing Role: Primary DC/DC converter supplying isolated ADCs, DACs, and digital isolators from unregulated 24V DC rails. Use Value: Wide 4.5–45V input accommodates brownouts and surges common in industrial power distribution; programmable current limit avoids overdesign of magnetics. |
| Distributed Power Systems | Battery-Operated Devices |
Use Scenario: Point-of-load regulation in distributed architectures where centralized 12V/24V bus powers multiple subsystems. IC Role / Device Role / Timing Role: Compact, thermally efficient buck converter delivering 5V/50mA to microcontroller subsystems or interface ICs. Use Value: 3mm × 3mm DFN package with exposed pad enables high-density board layouts; low dropout (100% duty cycle) extends usable input range down to 4.5V. |
Use Scenario: Power management in handheld test equipment, portable medical monitors, and remote data loggers. IC Role / Device Role / Timing Role: Main system regulator converting primary Li-ion or alkaline battery voltage to stable 3.3V for MCU and sensors. Use Value: 12µA no-load IQ maximizes battery runtime; internal soft-start prevents cold-start failure in low-temperature battery conditions. |
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#PBF | Higher 100mA output current, same 4.5–45V input, but 25µA IQ and larger 4mm × 4mm DFN package. | Required where >50mA load current or higher peak efficiency at medium loads is needed. | Select LT3643EDD#PBF only if full 100mA capability is required; otherwise LTC3642EDD#PBF offers lower IQ and smaller footprint. |
| TPS62130ARGTR | Lower 3–17V input range, 3A output, 17µA IQ, and different pinout - not pin-compatible; requires redesign. | Suitable for higher-current, lower-input-voltage applications like USB-powered systems or FPGA core rails. | Choose TPS62130ARGTR only for sub-17V inputs and >100mA loads; LTC3642EDD#PBF remains optimal for high-voltage, ultra-low-IQ needs. |
Compared with LT3643EDD#PBF, LTC3642EDD#PBF delivers 40% lower quiescent current and 25% smaller footprint at the cost of 50% lower output current; versus TPS62130ARGTR, it supports 2.6× higher input voltage but lacks scalability beyond 50mA, making it purpose-built for high-voltage, low-power edge nodes.
Availability
LTC3642EDD#PBF is available at Aetrix Electronics and suitable for industrial control supplies, 4–20mA current loops, and battery-operated devices requiring stable component supply with long-term lifecycle assurance.
Supply support for LTC3642EDD#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 its legacy of high-performance power management ICs with rigorous reliability testing and automotive-grade qualification paths.
The LTC3642 product line was designed specifically for high-input-voltage, ultra-low-quiescent-current DC/DC conversion in harsh industrial and portable environments where efficiency at micropower loads is critical.
FAQ
What is the maximum input voltage the LTC3642EDD#PBF can withstand without damage?
The LTC3642EDD#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 survive transient surges up to 60V while protecting downstream circuitry - a key requirement in automotive and industrial power systems where load-dump events occur.
Does the LTC3642EDD#PBF require external compensation components?
No, the LTC3642EDD#PBF features an internally compensated control loop. Unlike many buck controllers, it operates stably with only three external components for fixed-output versions (input capacitor, output capacitor, and inductor), eliminating the need for compensation resistors or capacitors and reducing design risk and board area.
How is the output voltage set on the LTC3642EDD#PBF?
The LTC3642EDD#PBF is available in fixed 3.3V and 5V versions (e.g., LTC3642EDD-3.3#PBF), where VOUT/VFB (Pin 6) connects directly to the output. For adjustable operation, an external resistive divider sets VOUT = 0.8V × (1 + R1/R2), with R1–R2 values typically in the megohm range to minimize no-load current.
What is the function of the HYST pin on the LTC3642EDD#PBF?
The HYST pin (Pin 7) is an open-drain logic output pulled low when the RUN pin voltage falls below 1.2V. It enables external hysteresis enhancement in resistor-divider RUN monitoring circuits - for example, connecting HYST to the RUN divider node increases effective hysteresis beyond the internal 110mV, preventing oscillation during slow-rising input voltages.
Can the LTC3642EDD#PBF operate with 100% duty cycle?
Yes, the LTC3642EDD#PBF supports 100% duty cycle operation, enabling dropout-free regulation when VIN approaches VOUT. This is essential in battery-powered systems where input voltage decays near the regulated output level - for instance, sustaining 3.3V output down to a 3.6V Li-ion cell under load.
LTC3642EDD#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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 45V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 45V
- 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#PBF FAQ
1.How can I place an order for LTC3642EDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3642EDD#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#PBF reliable?
The price and inventory of LTC3642EDD#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#PBF is usually 5 days.
3.What payment methods are accepted for LTC3642EDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3642EDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3642EDD#PBF?
LTC3642EDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3642EDD#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#PBF?
For technical support, including LTC3642EDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3642EDD#PBF requirements.
6.How does Aetrix verify that LTC3642EDD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3642EDD#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#PBF meets industry standards.
7.What is the process for return or replacement of LTC3642EDD#PBF?
All LTC3642EDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3642EDD#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#PBF part is unused and in its original packaging.
Return procedure for LTC3642EDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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