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Analog Devices Inc. LTC3646IDE-1#PBF
- Part No.:
- LTC3646IDE-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
LTC3646IDE-1#PBF.pdf
- Description:
- IC REG BUCK ADJ 1A 14DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,289
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Product details
Overview
LTC3646IDE-1#PBF from Analog Devices (formerly Linear Technology) is a 40V input, 1A synchronous step-down DC/DC converter with integrated high-side and low-side power MOSFETs, ±1% reference accuracy, 0.6V feedback threshold, and adjustable switching frequency from 200kHz to 3MHz. It operates in Burst Mode® for ultra-low quiescent current (140µA typical at no load) and supports forced continuous mode for ripple-sensitive applications - ideal for automotive intermediate bus conversion and industrial point-of-load supplies.
For engineers reviewing the LTC3646IDE-1#PBF datasheet, LTC3646IDE-1#PBF pinout, LTC3646IDE-1#PBF application, or LTC3646IDE-1#PBF equivalent, key selection criteria include its 0.6V–15V output voltage range (LTC3646-1 variant), –40°C to 125°C operating junction temperature, 14-lead 3mm × 4mm DFN package with exposed PGND pad, and controlled on-time current-mode architecture enabling stable regulation across wide VIN/VOUT ratios.
Technical Context
The LTC3646IDE-1#PBF implements a patented controlled on-time, current-mode control architecture that dynamically adjusts top-FET on-time based on VON/VIN ratio and programmed switching frequency, ensuring constant-frequency operation and avoiding output overvoltage during large step-downs. Its valley-current sensing and internal 0.6V reference enable precise regulation without external compensation when ITH is tied to INTVCC.
It integrates dual MOSFETs with 200mΩ (high-side) and 120mΩ (low-side) RDS(ON) at 5.5V, supports external clock synchronization via MODE/SYNC, and features robust protection including SVIN/PVIN overvoltage lockout (43.5V trip), short-circuit current limiting (0.9–1.5A valley limit), and thermal shutdown. The device uses SGND and PGND separation for noise immunity and requires EXPOSED PAD (Pin 15) soldered to PCB ground for thermal and electrical performance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.0V to 40V - supports automotive battery transients and industrial unregulated rails without pre-regulation. |
| Output Voltage Range | 0.6V to 15V - enables direct core supply for low-voltage processors and FPGAs. |
| Max Output Current | 1A guaranteed - sufficient for point-of-load conversion of microcontrollers, sensors, and interface ICs. |
| Feedback Reference | 0.6V ±1% - enables accurate output setting with standard resistor dividers; minimizes divider current error. |
| Quiescent Current | 140µA typical in Burst Mode - extends battery life in always-on systems like telematics and remote sensors. |
| Switching Frequency | 200kHz–3.0MHz programmable - balances inductor size (e.g., 3.3µH at 1MHz) vs. efficiency (peak 95%). |
| Junction Temp Range | –40°C to 125°C - qualified for under-hood automotive and industrial control environments. |
Pinout & Package
Package: 14-lead (4mm × 3mm) plastic DFN with exposed PGND pad (Pin 15), thermally enhanced for θJA = 43°C/W. Exposed pad must be soldered to PCB ground plane for thermal management and low-impedance return path.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SGND (Pin 1) | Analog Ground Reference | Low-noise return for feedback and error amplifier; must be isolated from noisy power ground until joined at single point. |
| VFB (Pin 2) | Feedback Input | Connects to resistor divider from VOUT; compares against 0.6V internal reference to regulate output voltage. |
| ITH (Pin 3) | Error Amplifier Output / Compensation Node | Loop compensation point; tie to INTVCC for internal compensation or add RC network for custom stability. |
| RT (Pin 4) | Oscillator Programming Input | Resistor to SGND sets frequency (200kHz–3MHz); connect to INTVCC for fixed 2.25MHz default. |
| VON (Pin 5) | On-Time Control Input | Connected to VOUT to scale on-time proportionally to output voltage, enabling wide VIN/VOUT ratios without overvoltage. |
| PGOOD (Pin 6) | Open-Drain Power-Good Flag | Pulls low if VFB deviates >7.5% from 0.6V; includes 15–30µs filter to suppress transient glitches. |
| MODE/SYNC (Pin 7) | Operating Mode Control / Clock Input | Tie to INTVCC for Burst Mode; to GND for forced continuous; drive with external clock for synchronization. |
| PVIN (Pin 8) | Main Power Input | High-voltage supply for top MOSFET; decouple with ≥10µF low-ESR capacitor to PGND. |
| SW (Pin 9) | Switch Node | Connects to inductor and boost capacitor; carries high dv/dt switching waveform - minimize trace area. |
| BOOST (Pin 10) | Bootstrap Supply | Capacitor between BOOST and SW generates gate drive voltage for high-side MOSFET. |
| INTVCC (Pin 11) | Internal 5.0V Regulator Output | Power source for control circuitry; decouple with ≥4.7µF low-ESR cap to PGND. |
| EXTVCC (Pin 12) | External Bias Input | Accepts 4.5–6.0V external supply to reduce power loss; tie to SGND if unused. |
| RUN (Pin 13) | Enable Input | Active-high; enables regulator when >1.21V; hysteresis ensures clean startup/shutdown. |
| SVIN (Pin 14) | Supply Sense Input | Must match PVIN voltage to maintain correct on-time calculation and frequency stability. |
| PGND (Exposed Pad) | Power Ground Return | Primary return path for high-current switch node; must be soldered to solid PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® Operation | Reduces no-load IQ to 140µA while maintaining ±1% output regulation - critical for battery-backed systems. |
| Controlled On-Time Architecture | Enables stable 0.6V–15V output from 4V–40V input without risk of overvoltage, even at light loads. |
| Integrated Dual MOSFETs | 200mΩ/120mΩ RDS(ON) at 5.5V eliminates external switches and simplifies layout for compact 1A designs. |
| Programmable Switching Frequency | 200kHz–3.0MHz via RT resistor or external clock - allows optimization of efficiency vs. EMI vs. component size. |
| Robust Protection Suite | Includes SVIN overvoltage lockout (43.5V), short-circuit current limit (1.2A typ), thermal shutdown, and PGOOD monitoring. |
| Thermally Enhanced DFN | 14-lead 3mm × 4mm package with exposed PGND pad delivers θJA = 43°C/W - supports 1A continuous in compact layouts. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering 1.2V/3.3V/5V rails for SoC, display controller, and CAN transceivers in vehicle head units. IC Role / Device Role / Timing Role: Primary buck converter delivering regulated intermediate bus from 9–16V battery rail. Use Value: 40V input rating withstands load-dump transients; Burst Mode extends standby time during ignition-off periods. |
Use Scenario: Generating 3.3V logic supply for microcontroller and analog front-end in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Point-of-load regulator converting 24V industrial bus to low-voltage digital supply. Use Value: –40°C to 125°C rating ensures reliability in uncooled enclosures; 140µA IQ reduces self-heating in sealed housings. |
| Medical Sensor Hub | Test & Measurement Equipment |
Use Scenario: Providing clean, low-noise 1.8V/2.5V supply for ADCs, amplifiers, and wireless transceivers in portable diagnostics. IC Role / Device Role / Timing Role: Low-quiescent-current buck regulator powering always-on sensor acquisition circuitry. Use Value: Forced continuous mode option eliminates Burst Mode switching noise near sensitive analog signal paths. |
Use Scenario: Generating stable 5V/12V auxiliary rails for FPGA configuration, DAC bias, and op-amp supplies in bench instruments. IC Role / Device Role / Timing Role: High-accuracy, low-drift intermediate regulator supporting precision analog subsystems. Use Value: ±1% reference and tight line/load regulation ensure consistent measurement accuracy across input and load variations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QDDARQ1 | 4.5–65V input, 0.5A max, 1.5MHz fixed freq, no Burst Mode, AEC-Q100 Grade 1 | Higher VIN, lower IOUT; lacks low-IQ sleep mode but offers automotive qualification | Select for 65V transient tolerance where 1A is not required and AEC-Q100 compliance is mandatory. |
| TPS54202DRCT | 4.5–28V input, 2A max, 400kHz–2.5MHz, 40µA IQ in Eco-mode, 10-pin WSON | Lower VIN ceiling, higher current, smaller package; Eco-mode less efficient than Burst Mode at ultra-light loads | Select for cost-sensitive 2A designs below 28V with moderate IQ requirements and space-constrained layouts. |
Compared with LM5164QDDARQ1 and TPS54202DRCT, the LTC3646IDE-1#PBF uniquely combines 40V input, 1A output, 140µA Burst Mode IQ, and 0.6V–15V programmable VOUT in a thermally optimized DFN - making it optimal for high-ratio, low-power industrial and automotive point-of-load applications where efficiency at light loads and thermal performance are prioritized.
Availability
LTC3646IDE-1#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, medical sensor hubs, and test equipment requiring stable component supply across extended temperature ranges.
Supply support for LTC3646IDE-1#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 LTC3646IDE-1#PBF belongs to Linear's high-voltage monolithic buck converter product line, designed specifically for reliable, high-efficiency DC/DC conversion in harsh environments with wide input ranges and stringent light-load efficiency demands.
FAQ
What is the output voltage range supported by the LTC3646IDE-1#PBF?
The LTC3646IDE-1#PBF supports an output voltage range of 0.6V to 15V, as defined by its LTC3646-1 variant designation. This range is enabled by the internal 0.6V feedback reference and the controlled on-time architecture, allowing precise regulation down to sub-1V levels for modern low-voltage ICs while maintaining stability across wide input-output differentials. The actual achievable VOUT depends on external resistor divider values connected to the VFB pin.
How does the LTC3646IDE-1#PBF achieve high efficiency at light loads?
The LTC3646IDE-1#PBF achieves high light-load efficiency through Burst Mode® operation, which reduces quiescent current to 140µA typical by disabling both power MOSFETs and entering a low-power sleep state when output current drops near zero. During Burst Mode, the part wakes periodically to deliver energy packets to the output capacitor, minimizing switching and gate drive losses - a key advantage over forced continuous mode in battery-powered or standby applications.
Can the LTC3646IDE-1#PBF be synchronized to an external clock?
Yes, the LTC3646IDE-1#PBF can be synchronized to an external clock via the MODE/SYNC pin. When driven with a clean square wave within 0.2–3.0MHz, the device adjusts its top-FET on-time to match the applied frequency and operates in forced continuous mode. An external resistor must still be connected to the RT pin, sized to correspond to the target frequency, to ensure proper oscillator biasing and loop stability.
What is the purpose of the VON pin on the LTC3646IDE-1#PBF?
The VON pin on the LTC3646IDE-1#PBF provides the on-time control loop with real-time information about the output voltage. By connecting VON directly to VOUT, the device scales its switching on-time proportionally to VOUT, enabling stable regulation across very wide input-to-output voltage ratios (e.g., 40V → 1.2V) without risking output overvoltage - a core feature of its patented controlled on-time architecture.
Is thermal management critical for the LTC3646IDE-1#PBF in 1A operation?
Yes, thermal management is critical: the LTC3646IDE-1#PBF uses a 14-lead 3mm × 4mm DFN with an exposed PGND pad (Pin 15) that must be soldered to a substantial PCB copper area to achieve its rated θJA = 43°C/W. Without proper thermal vias and ground plane connection, junction temperature can exceed 125°C under 1A continuous load at elevated ambient temperatures, triggering thermal shutdown or degrading long-term reliability.
LTC3646IDE-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 14-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):
- 4V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 15V
- Current - Output:
- 1A
- Frequency - Switching:
- 200kHz ~ 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-DFN (4x3)
LTC3646IDE-1#PBF FAQ
1.How can I place an order for LTC3646IDE-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3646IDE-1#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 LTC3646IDE-1#PBF reliable?
The price and inventory of LTC3646IDE-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3646IDE-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC3646IDE-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3646IDE-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3646IDE-1#PBF?
LTC3646IDE-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3646IDE-1#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 LTC3646IDE-1#PBF?
For technical support, including LTC3646IDE-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3646IDE-1#PBF requirements.
6.How does Aetrix verify that LTC3646IDE-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3646IDE-1#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 LTC3646IDE-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC3646IDE-1#PBF?
All LTC3646IDE-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3646IDE-1#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 LTC3646IDE-1#PBF part is unused and in its original packaging.
Return procedure for LTC3646IDE-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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