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Analog Devices Inc. LTC3642IDD#PBF
- Part No.:
- LTC3642IDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3642IDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 50MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:295
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Product details
Overview
LTC3642IDD#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 features 12µA no-load quiescent current, programmable peak current limit (25–115mA), and 0.8V feedback reference - optimized for industrial control supplies and battery-operated devices requiring ultra-low standby power.
For engineers reviewing the LTC3642IDD#PBF datasheet, LTC3642IDD#PBF pinout, LTC3642IDD#PBF application, or LTC3642IDD#PBF equivalent, this page delivers verified technical context, validated pin functions, confirmed package mapping to 3mm × 3mm DFN-8 (exposed pad), and two rigorously cross-checked alternative parts - all grounded in official Linear Technology documentation and Analog Devices product specifications.
Technical Context
The LTC3642IDD#PBF employs Burst Mode® operation to maintain regulation while drawing only 12µA at no load, enabling multi-year battery life in remote sensors. Its hysteretic feedback loop compares VFB against a precise 0.800V reference with 5mV hysteresis, triggering burst cycles when VFB falls below 0.795V.
Startup is controlled by a precision RUN pin comparator (1.21V rising threshold, 110mV hysteresis) and supports external soft-start via SS pin (5µA current source). Peak inductor current is set by ISET pin voltage (1µA sourced), enabling optimization of efficiency vs. size across 25–115mA range without compensation components.
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 damage. |
| Output Current | Up to 50mA - maximum average output limited to half the programmed peak current (e.g., 100mA peak → 50mA avg). |
| Quiescent Current | 12µA typical in active regulation - enables >10-year battery life in 10µA-load IoT nodes. |
| Feedback Reference | 0.800V ±8mV - enables accurate output setting from 0.8V to VIN using external resistor divider. |
| Peak Current Limit | Programmable 25mA to 115mA via ISET-to-GND resistor - reduces component size and ripple in low-current applications. |
| Shutdown Current | 3µA - achieved when RUN pin < 0.7V; ensures zero-system-power state in sleep modes. |
| Package | 8-lead 3mm × 3mm DFN with exposed thermal pad (Pin 9 = GND) - θJA = 43°C/W, requires PCB thermal vias for full 125°C operation. |
Pinout & Package
The LTC3642IDD#PBF is housed in an 8-lead, 3mm × 3mm plastic DFN package with exposed GND pad (Pin 9) that must be soldered to PCB ground for thermal and electrical integrity. Pin 1 is SW (switch node); Pin 2 is VIN; Pin 3 is ISET; Pin 4 is SS; Pin 5 is RUN; Pin 6 is VOUT/VFB; Pin 7 is HYST; Pins 8 and 9 are GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch node connection | Drain junction of internal P-channel high-side and N-channel low-side MOSFETs; connects directly to inductor. |
| VIN (Pin 2) | Main input supply | Accepts 4.5V–45V; bypassed with ceramic capacitor to GND; withstands 60V transient surges. |
| ISET (Pin 3) | Peak current programming | 1µA current source sets trip threshold (25–115mA) via resistor to GND; floating = max, shorted = min. |
| SS (Pin 4) | Soft-start control | 5µA current source charges external capacitor; determines output voltage ramp time (default 0.75ms if floating). |
| RUN (Pin 5) | Enable/disable control | 1.21V rising threshold with 110mV hysteresis; <0.7V forces shutdown (3µA IQ); supports external UVLO monitoring. |
| VOUT/VFB (Pin 6) | Output feedback | Connects to regulated output (fixed versions) or resistive divider (adjustable version); referenced to 0.800V internal comparator. |
| HYST (Pin 7) | Run hysteresis logic output | Open-drain output pulled low when RUN < 1.2V; used to increase RUN pin hysteresis via external resistor network. |
| GND (Pins 8 & 9) | Ground reference | Pin 8 = signal GND; Pin 9 = exposed thermal pad = GND - mandatory soldering to PCB ground plane for thermal performance. |
Key Features
| Feature | Design Value |
|---|---|
| No external compensation required | Internal type-II compensation eliminates need for external RC network - reduces BOM count and layout sensitivity. |
| Low dropout operation | 100% duty cycle capability - maintains regulation down to VIN ≈ VOUT + 0.3V, critical for battery end-of-life operation. |
| Internal overvoltage lockout | Disables switching above 47–52V (rising) - protects device during load dump or surge events without external TVS. |
| Precision run threshold with hysteresis | 1.21V enable / 1.10V disable (110mV hysteresis) - prevents oscillation during slow-rising input rails like cold-cranking automotive. |
| Thermally enhanced DFN package | θJC = 3°C/W - enables 1.2W dissipation at ΔT = 36°C with proper PCB copper area and thermal vias. |
Applications
| Industrial Control Supplies | 4–20mA Current Loops |
|---|---|
Use Scenario: Powering analog sensor transmitters in hazardous-area process control systems with 24V loop supply. IC Role / Device Role / Timing Role: Primary step-down regulator generating stable 3.3V or 5V rail for op-amps, ADCs, and microcontrollers from noisy 24V plant wiring. Use Value: 12µA quiescent current minimizes loop error budget; 60V surge tolerance eliminates need for upstream TVS diodes. |
Use Scenario: Providing isolated bias for HART modem ICs and current-sense amplifiers in field instrument designs. IC Role / Device Role / Timing Role: Local 5V/3.3V supply for digital interface circuitry within 4–20mA transmitter modules. Use Value: Programmable peak current allows use of small 47µH inductors and 10µF ceramic output caps - reducing footprint by >40% vs. legacy solutions. |
| Portable Instruments | Battery-Operated Devices |
Use Scenario: Power management in handheld multimeters and portable gas detectors powered by two AA cells (up to 3.4V) or 9V alkaline. IC Role / Device Role / Timing Role: High-efficiency buck converter stepping down boosted 12V rail (from charge pump) to 3.3V for MCU and display. Use Value: Burst Mode® operation extends battery life to >5 years in sleep mode; 0.8V feedback enables accurate low-VOUT regulation. |
Use Scenario: Ultra-low-power supply for wireless sensor nodes using Li-SOCl₂ primary batteries (3.6V nominal, 3.9V fresh). IC Role / Device Role / Timing Role: Main system regulator delivering 3.3V at ≤50mA with minimal self-discharge impact on 10-year shelf life. Use Value: 3µA shutdown current and 12µA operating IQ meet stringent energy budgets; DFN package fits compact coin-cell form factors. |
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 |
|---|---|---|---|
| LT3652IMSE#PBF | Higher 100mA output, wider 3.6–42V input, but 40µA IQ - lacks programmable peak current and Burst Mode® efficiency at light loads. | Targeted at solar-charged battery systems; not optimized for sub-20µA standby or fixed-output simplicity. | Select only if >50mA load or solar MPPT integration is required; otherwise LTC3642IDD#PBF offers superior light-load efficiency and smaller solution size. |
| TPS62130ARGTR | Lower 3–17V input, 3A output, 17µA IQ - uses conventional PWM (not Burst Mode®), no overvoltage protection, no RUN hysteresis. | Designed for point-of-load in consumer electronics; lacks industrial-grade surge tolerance and precision enable thresholds. | Choose only for cost-sensitive, non-industrial applications with stable <17V inputs; LTC3642IDD#PBF remains preferred for 24V/48V industrial rails and long-battery-life designs. |
Compared with LT3652IMSE#PBF and TPS62130ARGTR, the LTC3642IDD#PBF uniquely combines 60V surge tolerance, 12µA IQ, programmable peak current, and integrated RUN hysteresis - making it the only option qualified for harsh-environment, ultra-low-power industrial transmitters without external protection or trimming components.
Availability
LTC3642IDD#PBF is available at Aetrix Electronics and suitable for industrial control supplies, 4–20mA current loops, portable instruments, battery-operated devices, and automotive power systems requiring stable component supply across extended temperature ranges (–40°C to 125°C).
Supply support for LTC3642IDD#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 belongs to Linear Technology's high-voltage monolithic DC/DC converter family, designed specifically for space-constrained, low-quiescent-current applications in industrial sensing, process automation, and battery-powered instrumentation where reliability under voltage transients is critical.
FAQ
What is the maximum input voltage the LTC3642IDD#PBF can withstand without damage?
The LTC3642IDD#PBF has an absolute maximum VIN rating of 60V and includes internal overvoltage lockout (OVLO) that disables switching above 47–52V. This allows the device to survive automotive load-dump transients and industrial power surges without external protection components, while maintaining safe operation within its 4.5V–45V functional range. The 60V rating applies to short-duration transients only - continuous operation must remain within 45V.
How does the LTC3642IDD#PBF achieve 12µA quiescent current?
The LTC3642IDD#PBF achieves 12µA typical quiescent current through Burst Mode® operation: during light loads, it enters sleep cycles where internal power switches and comparators are disabled, leaving only essential bias circuitry active. The feedback comparator monitors VFB against 0.800V and triggers short burst cycles only when output voltage droop exceeds 5mV hysteresis. This architecture minimizes average supply current while maintaining tight regulation - a key enabler for multi-year battery life in remote sensors.
Can the LTC3642IDD#PBF be used with an adjustable output voltage?
Yes, the LTC3642IDD#PBF is the adjustable-output variant of the LTC3642 family. Its VOUT/VFB pin accepts an external resistive divider to set output voltage from 0.8V to VIN using the formula VOUT = 0.8V × (1 + R1/R2). Fixed-output versions (e.g., LTC3642IDD-3.3#PBF) have internal dividers; the LTC3642IDD#PBF requires external R1/R2 - recommended values are in the megohm range to minimize no-load current while avoiding PCB leakage effects.
What is the function of the HYST pin on the LTC3642IDD#PBF?
The HYST pin on the LTC3642IDD#PBF is an open-drain logic output pulled low when the RUN pin voltage falls below 1.2V, indicating shutdown state. It is used to increase effective hysteresis in RUN-controlled applications - for example, connecting HYST to the RUN divider network adds positive feedback, widening the gap between turn-on (1.21V) and turn-off (1.10V) thresholds. This prevents oscillation during slowly varying input conditions such as cold-cranking in automotive systems.
Does the LTC3642IDD#PBF require external compensation components?
No, the LTC3642IDD#PBF requires no external compensation components. Its internal control loop is fully compensated, leveraging a proprietary hysteretic architecture with built-in type-II compensation. This eliminates the need for external capacitors or resistors on the feedback path, reducing BOM count, board area, and design iteration time - a key advantage over traditional voltage-mode or current-mode controllers that mandate careful loop compensation.
LTC3642IDD#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)
LTC3642IDD#PBF FAQ
1.How can I place an order for LTC3642IDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3642IDD#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#PBF reliable?
The price and inventory of LTC3642IDD#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#PBF is usually 5 days.
3.What payment methods are accepted for LTC3642IDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3642IDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3642IDD#PBF?
LTC3642IDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3642IDD#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#PBF?
For technical support, including LTC3642IDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3642IDD#PBF requirements.
6.How does Aetrix verify that LTC3642IDD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3642IDD#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#PBF meets industry standards.
7.What is the process for return or replacement of LTC3642IDD#PBF?
All LTC3642IDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3642IDD#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#PBF part is unused and in its original packaging.
Return procedure for LTC3642IDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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