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Analog Devices Inc. LTC3646EMSE#TRPBF
- Part No.:
- LTC3646EMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3646EMSE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1A 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,400
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Product details
Overview
LTC3646EMSE#TRPBF from Analog Devices (formerly Linear Technology) is a 40V input, 1A synchronous step-down DC/DC converter with integrated high-side and synchronous power MOSFETs. It delivers ±1% output voltage accuracy, operates from 4.0V to 40V input, supports 2.0V–30V output range, achieves up to 95% efficiency, and draws only 140µA quiescent current in Burst Mode at no load - ideal for industrial point-of-load and automotive intermediate bus supplies.
For engineers reviewing the LTC3646EMSE#TRPBF datasheet, LTC3646EMSE#TRPBF pinout, LTC3646EMSE#TRPBF application, or LTC3646EMSE#TRPBF equivalent, this page provides verified package mapping (16-lead MSOP), confirmed pin functions, real-world efficiency vs. load curves, validated alternative parts with technical differences, and design-critical timing and protection behavior - all extracted from the official LTC3646 datasheet Rev. FC.
Technical Context
The LTC3646EMSE#TRPBF implements a current-mode, controlled-on-time architecture with valley-current sensing and internal error amplifier transconductance of 300µS. Its patented on-time calculation - tON = VON/(VIN × fO) - enables stable operation across wide input-output ratios without output overvoltage risk.
It integrates dual MOSFETs with 200mΩ top-switch and 120mΩ bottom-switch RDS(ON) at 5.5V, supports selectable Burst Mode or forced continuous operation via MODE/SYNC pin, and features programmable switching frequency (200kHz–3.0MHz) using an external RT resistor or synchronization to external clock.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.0V to 40V - supports direct connection to 24V/36V industrial rails and automotive battery systems with transient tolerance up to 45V absolute max. |
| Output Current | 1A guaranteed - sustained full-load capability with valley current limit of 0.9A–1.5A and negative limit of –0.3A. |
| Feedback Reference | 0.6V ±1% - enables precise output programming from 2.0V to 30V using standard resistor dividers. |
| Quiescent Current | 140µA typical in Burst Mode - maintains regulation at ultra-low loads while minimizing standby power in always-on systems. |
| Switching Frequency | 200kHz to 3.0MHz - adjustable via RT resistor or external sync; default 2.25MHz when RT tied to INTVCC. |
| Package | 16-lead MSOP with exposed thermal pad - θJA = 38°C/W; PGND-connected exposed pad must be soldered for thermal and electrical integrity. |
| Protection Features | Input overvoltage lockout (43.5V rising), undervoltage lockout (3.2V falling), short-circuit tolerant, PGOOD with 70-cycle filter, and thermal shutdown. |
Pinout & Package
Package: 16-lead plastic MSOP (MSE) with exposed thermal pad (Pin 17), rated for –40°C to +85°C operating junction temperature. Exposed pad is PGND and must be soldered to PCB ground plane for thermal performance and low-impedance return path.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SGND (Pin 1) | Analog Ground Reference | Low-noise reference for feedback and compensation; separate from PGND to minimize noise coupling into error amplifier. |
| VFB (Pin 2) | Feedback Input | Connects to resistor divider; compares against 0.6V internal reference to regulate output voltage with ±1% accuracy. |
| ITH (Pin 3) | Error Amplifier Output | Loop compensation node; connects to RC network for stability tuning or ties to INTVCC for internal compensation. |
| RT (Pin 4) | Oscillator Programming | Resistor-to-ground sets switching frequency from 200kHz to 3.0MHz; floating prohibited. |
| VON (Pin 5) | On-Time Voltage Input | Connected to VOUT to scale on-time inversely with VIN, enabling constant-frequency operation across wide step-down ratios. |
| PGOOD (Pin 6) | Power-Good Status | Open-drain output pulled low if VFB deviates >7.5% from 0.6V; includes 15–30µs filter to suppress transient glitches. |
| MODE/SYNC (Pin 7) | Operating Mode Control | Tied to INTVCC → Burst Mode; tied to GND → forced continuous; driven by external clock → synchronized forced continuous. |
| PVIN (Pins 9,10) | Main Power Input | High-voltage supply for top MOSFET; requires ≥10µF low-ESR capacitor to PGND for transient suppression. |
| SW (Pin 11) | Switch Node | Drives external inductor and boost capacitor; carries high di/dt; must be routed with minimal loop area. |
| BOOST (Pin 12) | Bootstrap Supply | Capacitor between BOOST and SW generates gate drive voltage for top MOSFET; swing = INTVCC to PVIN + INTVCC. |
| INTVCC (Pin 13) | Internal 5.0V Regulator | Supplies control circuitry; decoupled with ≥4.7µF low-ESR cap to PGND; disabled when RUN = low. |
| EXTVCC (Pin 14) | External Bias Input | Accepts 4.5V–6.0V external supply to improve efficiency; tie to SGND if unused. |
| RUN (Pin 15) | Enable Input | Active-high enable; threshold 1.17V–1.26V rising; hysteresis 110mV; leakage <±1µA at 1.3V. |
| SVIN (Pin 16) | Signal Input Supply | Must match PVIN voltage to ensure accurate on-time calculation and stable frequency; decoupled with >1µF low-ESR cap to SGND. |
| PGND (Exposed Pad) | Power Ground Return | Common return for bottom MOSFET, boost capacitor, and input/output capacitors; thermal and electrical path to 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 or energy-harvesting systems. |
| Controlled On-Time Architecture | Enables stable 40V→3.3V (12:1) conversion without output overvoltage risk, even under light loads or fast line transients. |
| Integrated Dual MOSFETs | 200mΩ/120mΩ RDS(ON) at 5.5V eliminates external switches and reduces BOM count, layout area, and gate-drive complexity. |
| Programmable Switching Frequency | 200kHz–3.0MHz adjustment via single RT resistor allows optimization of inductor size (high-freq) vs. efficiency (low-freq). |
| Robust Protection Suite | Includes input OV/UV lockout, short-circuit current limiting, PGOOD with glitch filtering, and thermal shutdown - suitable for unattended industrial deployment. |
| Flexible Compensation | Supports both internal (ITH → INTVCC) and external (RC network on ITH) loop compensation for rapid prototyping or precision stability tuning. |
Applications
| Industrial Point-of-Load Supply | Automotive Intermediate Bus Converter |
|---|---|
Use Scenario: Powering FPGA I/O banks or microcontroller peripherals from a 24V rail in factory automation controllers. IC Role / Device Role / Timing Role: Primary step-down regulator delivering regulated 3.3V/1.8V with tight load-transient response and low-noise operation. Use Value: 95% peak efficiency and 140µA Burst Mode IQ extend system uptime during idle cycles and reduce thermal load on sealed enclosures. |
Use Scenario: Converting 12V/24V vehicle battery to 5V for infotainment USB ports and ADAS camera modules. IC Role / Device Role / Timing Role: High-input-voltage buck converter with 40V absolute max rating and built-in OV/UV protection for cold-crank and load-dump resilience. Use Value: 4.0V–40V input range and 43.5V OV lockout ensure reliable startup and operation across automotive battery transients per ISO 7637-2. |
| Telecom Intermediate Bus Supply | Test & Measurement Equipment Rail Generator |
Use Scenario: Generating 5V/12V intermediate rails from 48V backplane in modular telecom line cards. IC Role / Device Role / Timing Role: Efficient, compact DC/DC stage supporting high-density board layouts with minimal external components. Use Value: 16-lead MSOP package with exposed PGND pad enables thermal management in constrained spaces; 2.25MHz default frequency allows use of 3.3µH inductors. |
Use Scenario: Providing clean, adjustable analog supply rails (e.g., ±15V, +5V) in portable benchtop instruments with battery backup. IC Role / Device Role / Timing Role: Precision-regulated power source with ±1% VREF and low output ripple in forced continuous mode. Use Value: Selectable forced continuous mode eliminates Burst Mode noise, ensuring stable operation for sensitive ADCs and DACs without EMI interference. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3646EMSE-1#TRPBF | Same package and pinout; supports 0.6V–15V output range (vs. 2.0V–30V); uses different VON scaling for lower-VOUT optimization. | Preferred for sub-2V outputs (e.g., core logic, DDR memory); not suitable for 3.3V+ rails requiring >2V minimum. | Select LTC3646EMSE#TRPBF for outputs ≥2.0V; choose -1 variant only when targeting 0.6V–1.8V with tighter low-VOUT accuracy. |
| LT8610EMSE#TRPBF | 42V input, 3.5A output, 2.5µA IQ in Silent Switcher mode; different pinout, no VON pin, fixed 200kHz–3MHz sync range. | Better suited for higher-current, ultra-low-noise applications; lacks controlled-on-time architecture and wide-VOUT programmability. | Use LT8610EMSE#TRPBF where <2.5µA IQ or EMI reduction is mandatory; retain LTC3646EMSE#TRPBF for wide output range, simple VON-based ratio control, and cost-sensitive 1A designs. |
Compared with LTC3646EMSE-1#TRPBF, the LTC3646EMSE#TRPBF offers broader output flexibility (2.0–30V vs. 0.6–15V) and identical thermal performance in MSOP; versus LT8610EMSE#TRPBF, it trades higher IQ and EMI performance for simpler compensation, lower BOM count, and deterministic on-time behavior across extreme input-output ratios.
Availability
LTC3646EMSE#TRPBF is available at Aetrix Electronics and suitable for industrial point-of-load supplies, automotive intermediate bus converters, and telecom power modules requiring stable component supply, long-term lifecycle support, and guaranteed parametric compliance across –40°C to +85°C.
Supply support for LTC3646EMSE#TRPBF 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 technical and manufacturing continuity for the LTC portfolio. Linear's legacy expertise in precision analog and power management remains embedded in product design and validation.
The LTC3646 belongs to Linear's high-voltage monolithic buck regulator family, engineered specifically for robust, wide-input industrial and automotive power conversion where simplicity, reliability, and wide output range outweigh ultra-low-IQ or EMI-optimized requirements.
FAQ
What is the maximum input voltage the LTC3646EMSE#TRPBF can withstand?
The LTC3646EMSE#TRPBF has an absolute maximum PVIN/SVIN rating of 45V, with overvoltage lockout triggered at 43.5V (rising). Continuous operation is specified from 4.0V to 40V. Transient spikes beyond 40V must be clamped externally to avoid exceeding the 45V absolute maximum, as prolonged exposure above this level risks permanent damage per Absolute Maximum Ratings.
Does the LTC3646EMSE#TRPBF require external compensation components?
The LTC3646EMSE#TRPBF supports both internal and external compensation. Tying ITH to INTVCC enables default internal compensation for quick evaluation. For optimized stability across varying loads or output capacitors, external RC components on ITH are required - the datasheet provides design equations and example values for common configurations including ceramic and polymer output caps.
How does the VON pin function in the LTC3646EMSE#TRPBF?
The VON pin in the LTC3646EMSE#TRPBF feeds the output voltage directly into the on-time controller, enabling the device to calculate tON = VON/(VIN × fO). When connected to VOUT, it ensures constant switching frequency and stable regulation across wide input-output ratios - a key enabler for 40V→3.3V conversion without output overvoltage risk.
Can the LTC3646EMSE#TRPBF operate in forced continuous mode?
Yes - the LTC3646EMSE#TRPBF enters forced continuous mode when the MODE/SYNC pin is pulled to ground. In this mode, both MOSFETs switch continuously regardless of load, eliminating Burst Mode noise and ensuring predictable EMI profile. This is essential for noise-sensitive analog circuits, though quiescent current rises to ~620µA.
What is the thermal performance of the LTC3646EMSE#TRPBF in its MSOP package?
The LTC3646EMSE#TRPBF in the 16-lead MSOP (MSE) package has a junction-to-ambient thermal resistance (θJA) of 38°C/W when mounted on a standard 2-layer PCB with the exposed PGND pad fully soldered to a 1-in² copper area. Maximum junction temperature is 150°C; derating is required above 125°C ambient to maintain reliability and lifetime.
LTC3646EMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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#TRPBF FAQ
1.How can I place an order for LTC3646EMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3646EMSE#TRPBF 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#TRPBF reliable?
The price and inventory of LTC3646EMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3646EMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3646EMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3646EMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3646EMSE#TRPBF?
LTC3646EMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3646EMSE#TRPBF 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#TRPBF?
For technical support, including LTC3646EMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3646EMSE#TRPBF requirements.
6.How does Aetrix verify that LTC3646EMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3646EMSE#TRPBF 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#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3646EMSE#TRPBF?
All LTC3646EMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3646EMSE#TRPBF, 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#TRPBF part is unused and in its original packaging.
Return procedure for LTC3646EMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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