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Analog Devices Inc. LTC3646EMSE#PBF
- Part No.:
- LTC3646EMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3646EMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 1A 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,780
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Product details
Overview
LTC3646EMSE#PBF from Analog Devices (formerly Linear Technology) is a 40V input, 1A synchronous step-down DC/DC converter in a thermally enhanced 16-lead MSOP package. It features internal high-side and synchronous power FETs, ±1% reference accuracy, adjustable switching frequency from 200kHz to 3MHz, and selectable Burst Mode® or forced continuous operation - enabling high efficiency across wide load ranges in point-of-load and intermediate bus applications.
For engineers reviewing the LTC3646EMSE#PBF datasheet, LTC3646EMSE#PBF pinout, LTC3646EMSE#PBF application, or LTC3646EMSE#PBF equivalent, key selection criteria include its 4.0V–40V input range, 2.0V–30V output voltage capability, 140µA no-load quiescent current in Burst Mode, integrated soft-start, and robust short-circuit and overvoltage protection for automotive and industrial power rails.
Technical Context
The LTC3646EMSE#PBF implements a current-mode, controlled-on-time architecture with valley-current sensing and an internal 0.6V reference. Its on-time calculation tON = VON/(VIN × fO) enables stable regulation across large step-down ratios without output overvoltage risk. The device supports both internal compensation (via ITH-to-INTVCC connection) and external loop compensation for optimized transient response.
It integrates dual MOSFET drivers, a 5.0V INTVCC regulator (±2% tolerance), PGOOD monitoring with 7.5% UV/OV window and 30µs filter time, and SVIN/PVIN overvoltage lockout at 43.5V (2.5V hysteresis). RUN pin enable threshold is 1.21V with 110mV hysteresis, and MODE/SYNC pin selects between Burst Mode (INTVCC tie) and forced continuous mode (ground tie) or external clock synchronization.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.0V to 40V - supports wide-range industrial, automotive, and telecom inputs without pre-regulation. |
| Output Current | 1A guaranteed - delivers full rated load with thermal derating managed via exposed PGND pad soldering. |
| Reference Voltage | 0.6V ±1% - enables precise output setting from 2.0V to 30V using standard resistor dividers. |
| Quiescent Current | 140µA typical in Burst Mode - sustains regulation at ultra-light loads while minimizing standby power loss. |
| Switching Frequency | 200kHz to 3.0MHz (resistor-programmable) - balances inductor size, efficiency, and EMI performance. |
| Package | 16-Lead Plastic MSOP with exposed thermal pad - provides θJA = 38°C/W for reliable operation up to 85°C ambient. |
| Protection Features | Short-circuit, overtemperature, PVIN/SVIN overvoltage (43.5V), and PGOOD with 30µs filtering - ensures robust field operation. |
Pinout & Package
Package: 16-Lead Plastic MSOP (MSE), 4mm × 3mm footprint, exposed thermal pad (Pin 17) connected to PGND. Requires soldering of exposed pad to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SGND (Pin 1) | Analog Ground Reference | Low-noise return path for feedback and error amplifier; must be isolated from noisy power ground traces. |
| VFB (Pin 2) | Feedback Input | Connects to resistor divider from VOUT; compares against 0.6V reference to regulate output voltage. |
| ITH (Pin 3) | Error Amplifier Output | Loop compensation node - connect RC network externally or tie to INTVCC for internal compensation. |
| RT (Pin 4) | Oscillator Programming | Resistor-to-ground sets switching frequency (200kHz–3MHz); tie to INTVCC for 2.25MHz default. |
| VON (Pin 5) | On-Time Control Input | Connected to VOUT to scale on-time proportionally - enables constant-frequency operation across wide VIN/VOUT ratios. |
| PGOOD (Pin 6) | Power Good Status | Open-drain output pulled low if VFB deviates >7.5% from 0.6V; includes 30µs glitch filter. |
| MODE/SYNC (Pin 7) | Operating Mode Control | Ground = forced continuous; INTVCC = Burst Mode; external clock = synchronized forced continuous. |
| SVIN (Pin 16) | Internal Circuit Supply | Must match PVIN voltage to ensure accurate on-time calculation and stable frequency. |
| PVIN (Pins 9,10) | Main Power Input | High-voltage input for top switch; requires ≥10µF low-ESR ceramic decoupling to PGND. |
| SW (Pin 11) | Switch Node | Connects to inductor and boost capacitor; carries high dv/dt switching waveform. |
| BOOST (Pin 12) | Bootstrap Supply | Capacitor between BOOST and SW generates gate drive voltage for top MOSFET. |
| INTVCC (Pin 13) | Internal 5.0V Regulator | Supplies control circuitry; decouple with ≥4.7µF low-ESR capacitor to PGND. |
| EXTVCC (Pin 14) | External Bias Input | Optional 4.5V–6.0V supply for improved efficiency; tie to SGND if unused. |
| RUN (Pin 15) | Enable Input | Active-high enable with 1.21V threshold and 110mV hysteresis; drives internal logic and regulators. |
| PGND (Exposed Pad) | Power Ground Return | Primary thermal and current return path - must be soldered to solid PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Patented Controlled On-Time Architecture | Enables stable regulation across 40V:2V (20:1) step-down ratio without output overvoltage risk. |
| Selectably Optimized Efficiency Modes | Burst Mode achieves 140µA IQ at no load; forced continuous eliminates low-frequency ripple for noise-sensitive circuits. |
| Integrated Dual Power Switches | Eliminates external MOSFETs and drivers - reduces BOM count, layout area, and gate-drive complexity. |
| Robust Protection Suite | Includes SVIN/PVIN OV lockout (43.5V), short-circuit current limiting (~1.2A), and thermal shutdown with hysteresis. |
| Flexible Frequency Control | Resistor-programmable (200kHz–3MHz) or synchronizable to external clock - supports EMI reduction and multi-rail coordination. |
| Thermally Enhanced MSOP Package | θJA = 38°C/W with exposed PGND pad - enables 1A operation in compact industrial and automotive PCB layouts. |
Applications
| Point-of-Load Power Supply | Intermediate Bus Converter |
|---|---|
Use Scenario: Providing regulated 3.3V or 5V from a 12V or 24V intermediate rail to FPGA I/O banks or microcontroller peripherals. IC Role / Device Role / Timing Role: Primary buck regulator delivering tightly regulated, low-noise DC power with fast transient response. Use Value: Achieves >92% efficiency at 500mA load with 12V input, minimizing heat buildup near sensitive digital ICs. |
Use Scenario: Stepping down 40V battery or PoE++ input to 12V or 5V for downstream DC/DC modules in industrial gateways. IC Role / Device Role / Timing Role: High-input-voltage primary converter enabling simplified multi-stage power architecture. Use Value: 40V absolute maximum rating and SVIN overvoltage protection allow direct connection to unregulated 36V nominal systems. |
| Automotive Body Control Module | Industrial Sensor Interface |
Use Scenario: Powering CAN transceivers, LIN controllers, and LED drivers from a 12V vehicle battery subject to load dump transients. IC Role / Device Role / Timing Role: Main system supply regulator with built-in 43.5V overvoltage lockout and thermal protection. Use Value: Survives ISO 7637-2 Pulse 5a (load dump) events without external TVS clamping due to integrated OV protection. |
Use Scenario: Generating stable 3.3V for precision ADCs, temperature sensors, and RS-485 transceivers in factory automation PLCs. IC Role / Device Role / Timing Role: Low-noise, high-PSRR power source ensuring measurement accuracy under varying load conditions. Use Value: 140µA Burst Mode IQ extends uptime in battery-backed sensor nodes; ±1% reference ensures <0.5% output drift over temperature. |
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 |
|---|---|---|---|
| LT8610EMSE#PBF | 42V input, 3.5A output, 2.5µA IQ in Silent Switcher mode; fixed 2MHz frequency; no VON pin or adjustable on-time. | Better suited for high-current, ultra-low-noise applications where EMI is critical; lacks wide-output-range flexibility. | Choose LT8610EMSE#PBF when >1A load or strict CISPR 25 Class 5 EMI compliance is required. |
| TPS54240DGQR | 40V input, 2.5A output, 110µA IQ; uses voltage-mode control; no integrated BOOT diode path; lower max frequency (3.5MHz). | Requires external bootstrap diode; less tolerant of extreme duty cycles; wider operating temp range (–40°C to 125°C). | Choose TPS54240DGQR when cost sensitivity outweighs layout simplicity and thermal performance is secondary. |
Compared with LT8610EMSE#PBF and TPS54240DGQR, the LTC3646EMSE#PBF uniquely combines 1A capability, programmable frequency, patented on-time control for wide VIN/VOUT ratios, and industry-leading 140µA Burst Mode IQ - making it optimal for space-constrained, wide-input industrial and automotive point-of-load designs where efficiency across light-to-full load is critical.
Availability
LTC3646EMSE#PBF is available at Aetrix Electronics and suitable for point-of-load power supplies, intermediate bus converters, and automotive body control modules requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to +85°C.
Supply support for LTC3646EMSE#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3646 belongs to Linear's high-voltage monolithic buck regulator product line, designed specifically for robust, efficient DC/DC conversion in harsh environments - emphasizing wide input range, integrated protection, and flexible control architecture for industrial and transportation applications.
FAQ
What is the maximum input voltage rating for the LTC3646EMSE#PBF?
The LTC3646EMSE#PBF has an absolute maximum PVIN/SVIN rating of 45V, with overvoltage lockout triggered at 43.5V (with 2.5V hysteresis). It operates continuously across 4.0V to 40V, making it suitable for 36V nominal automotive and industrial systems. Exceeding 45V risks permanent damage per Absolute Maximum Ratings.
Does the LTC3646EMSE#PBF support output voltages below 2.0V?
No - the LTC3646EMSE#PBF variant is specified for 2.0V to 30V output range. For sub-2.0V outputs (down to 0.6V), the pin-compatible LTC3646-1 family (e.g., LTC3646EMSE-1#PBF) must be used. The -1 suffix denotes the alternate feedback range; mixing variants invalidates output voltage accuracy and regulation guarantees.
How is switching frequency set on the LTC3646EMSE#PBF?
Switching frequency is set by connecting a resistor (RRT) from the RT pin (Pin 4) to SGND. RRT = 9×10¹⁰ / fO (Ω), supporting 200kHz to 3.0MHz. Alternatively, tying RT to INTVCC fixes fO at 2.25MHz. External clock synchronization is enabled by driving MODE/SYNC (Pin 7) with a clean square wave within 0.2–3.0MHz.
What thermal design considerations apply to the LTC3646EMSE#PBF?
The LTC3646EMSE#PBF uses a 16-lead MSOP with exposed PGND pad (Pin 17). To achieve θJA = 38°C/W and sustain 1A output, the pad must be fully soldered to a minimum 200mm² copper pour connected to inner-layer ground planes via ≥6 thermal vias. Insufficient thermal relief causes junction temperature rise beyond 150°C, triggering thermal shutdown.
Can the LTC3646EMSE#PBF operate without an external boost capacitor?
No - the LTC3646EMSE#PBF requires a boost capacitor (typically 0.01µF–0.1µF ceramic) between BOOST (Pin 12) and SW (Pin 11) to generate gate drive voltage for the high-side MOSFET. Omitting this capacitor prevents proper top-FET turn-on, causing regulation failure, excessive heating, or immediate shutdown. A Schottky diode may be added for high-duty-cycle reliability.
LTC3646EMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) 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):
- 2V
- Voltage - Output (Max):
- 30V
- 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:
- 16-MSOP-EP
LTC3646EMSE#PBF FAQ
1.How can I place an order for LTC3646EMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3646EMSE#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 LTC3646EMSE#PBF reliable?
The price and inventory of LTC3646EMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3646EMSE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3646EMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3646EMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3646EMSE#PBF?
LTC3646EMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3646EMSE#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 LTC3646EMSE#PBF?
For technical support, including LTC3646EMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3646EMSE#PBF requirements.
6.How does Aetrix verify that LTC3646EMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3646EMSE#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 LTC3646EMSE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3646EMSE#PBF?
All LTC3646EMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3646EMSE#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 LTC3646EMSE#PBF part is unused and in its original packaging.
Return procedure for LTC3646EMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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