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Analog Devices Inc. LTC3649EFE#PBF
- Part No.:
- LTC3649EFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3649EFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 4A 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:822
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Product details
Overview
LTC3649EFE#PBF from Analog Devices is a 60V, 4A synchronous monolithic step-down regulator in a 28-lead TSSOP package. It delivers rail-to-rail output (0V to VIN–0.5V) with single-resistor VOUT programming, ±0.8% output voltage accuracy, and programmable switching frequency from 300kHz to 3MHz. It supports Burst Mode® for high light-load efficiency (440µA IQ) and forced continuous mode for low ripple-used in industrial power supplies and automotive DC/DC conversion.
For engineers reviewing the LTC3649EFE#PBF datasheet, LTC3649EFE#PBF pinout, LTC3649EFE#PBF application, or LTC3649EFE#PBF equivalent, key selection factors include its 60V input rating, integrated 110mΩ/50mΩ MOSFETs, accurate current monitoring (±4%), input voltage regulation for MPPT, and thermally enhanced TSSOP package with exposed pad soldered to SGND.
Technical Context
The LTC3649EFE#PBF employs peak current mode control with internal compensation, enabling fast transient response and inherent cycle-by-cycle current limiting. Its error amplifier uses a precise 50µA reference at ISET to set VOUT = 50µA × RSET, while ITH serves as both compensation node and current-sense threshold modulator.
It integrates dual LDOs: one powered from VIN (3.3V INTVCC), another from EXTVCC (3.1V INTVCC) when VIN > 5V and EXTVCC > 3.2V-reducing thermal stress at high input voltages. Input voltage regulation (VINREG) and cable drop compensation leverage IMON's 1/40,000 current mirroring for adaptive loop control without external sense resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.1V to 60V - supports wide-input industrial and automotive battery systems including 24V/48V rails and transient-tolerant operation. |
| Output Current | Up to 4A - delivered continuously with thermal management via exposed pad; peak current limit programmable up to 6.6A. |
| Output Voltage Range | 0V to (VIN – 0.5V) - enables true rail-to-rail adjustment, e.g., 5V out from 5.5V input or 12V out from 60V input. |
| Switching Frequency | 300kHz to 3MHz (RT-programmable) - allows optimization of size (high fSW) vs. efficiency (low fSW) and EMI filtering. |
| Quiescent Current | 440µA (Burst Mode), 18µA (shutdown) - enables long battery life in always-on industrial sensors and telematics modules. |
| Output Accuracy | ±0.8% over line, load, and temperature - ensures stable MCU core voltage or ADC reference supply without post-regulation. |
| Current Monitoring | ±4% accuracy, no external sense resistor - provides real-time load telemetry and enables precise current limiting via IMON feedback. |
Pinout & Package
Package: 28-Lead Plastic TSSOP with exposed thermal pad (Pin 29) connected to SGND. Requires PCB soldering of exposed pad for thermal performance (θJA = 30°C/W) and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGND (Pins 1–5) | Power Ground Return | Low-impedance path for high di/dt switch currents; must be tied to local power ground plane under IC. |
| VIN (Pins 6, 7) | Main Input Supply | Accepts 3.1V–60V; powers internal circuitry and top/bottom MOSFETs; includes OVP (68V) and UVLO (2.65V). |
| RUN (Pin 8) | Enable Control Input | Logic-controlled start-up; 1.2V rising threshold with 120mV hysteresis-enables precise VIN undervoltage lockout via resistor divider. |
| SGND (Pins 9, 29) | Signal Ground Reference | Reference for error amp, ISET, IMON, VINREG; exposed pad (Pin 29) must be soldered to SGND for stability and thermal conduction. |
| MODE/SYNC (Pin 10) | Operating Mode Select | GND = Burst Mode; floating = forced continuous; external clock = synchronization with ±50% capture range. |
| PGOOD (Pin 11) | Power-Good Indicator | Open-drain output asserting low when VPGFB < 0.555V or > 0.645V-provides system-level power sequencing and fault detection. |
| IMON (Pin 13) | Current Monitor Output | 1/40,000-scale replica of average inductor current; enables lossless current sensing and programmable current limit. |
| ISET (Pin 17) | VOUT Programming Input | 50µA precision current source; VOUT = 50µA × RSET; soft-start implemented via capacitor to ground. |
| ITH (Pin 18) | Error Amplifier Output | Compensation node and peak-current threshold modulator; tying to INTVCC enables internal compensation. |
| EXTVCC (Pin 19) | External Bias Supply | Enables secondary LDO (3.1V) when >3.2V-reduces power dissipation vs. VIN-powered INTVCC at high input voltages. |
| SW (Pins 22–28) | Switch Node | Connection to inductor; carries full switching waveform; requires low-inductance layout and Kelvin routing for BOOST capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail output programming | VOUT adjustable from 0V to (VIN – 0.5V) using single resistor-eliminates need for external op-amps or DACs in variable-output systems. |
| Accurate current monitoring | ±4% tolerance without sense resistor-reduces BOM cost, board space, and power loss versus discrete shunt solutions. |
| Input voltage regulation (VINREG) | Programmable 2.0V threshold for MPPT or hold-up applications-enables dynamic input current limiting during brownouts or solar panel voltage sag. |
| Wire drop compensation | Implemented via IMON–ISET coupling-maintains point-of-load voltage accuracy across long traces or cables without additional feedback wiring. |
| Thermally enhanced TSSOP | 28-lead package with exposed SGND pad (θJA = 30°C/W)-delivers 4A output in compact footprint suitable for space-constrained industrial modules. |
Applications
| Industrial Power Supply | Automotive Body Control Module |
|---|---|
Use Scenario: 24V vehicle battery powers multiple 3.3V/5V subsystems in harsh environments with wide temperature and load transients. IC Role / Device Role / Timing Role: Primary buck converter delivering regulated 5V/4A to microcontroller, CAN transceiver, and sensor interface. Use Value: 60V input rating withstands load-dump transients; Burst Mode maintains <440µA quiescent current during sleep states; PGOOD enables safe MCU reset sequencing. | Use Scenario: Central body controller managing door locks, lighting, and HVAC with strict EMC and thermal constraints. IC Role / Device Role / Timing Role: High-efficiency 12V-to-3.3V conversion for low-power logic and communication peripherals. Use Value: Forced continuous mode ensures low output ripple (<10mVpp) for noise-sensitive CAN/LIN buses; IMON enables real-time load diagnostics and overcurrent protection. |
| Solar Charge Controller | Programmable Test Equipment |
Use Scenario: MPPT-based solar charge controller regulating battery charging voltage from variable PV array output (18–60V). IC Role / Device Role / Timing Role: Input-voltage-regulated buck stage controlling charge current based on VINREG feedback. Use Value: VINREG pin allows direct implementation of MPPT algorithm by clamping input current when panel voltage drops below optimal point. | Use Scenario: Bench power supply module requiring digitally adjustable output voltage and current limit across multiple DUTs. IC Role / Device Role / Timing Role: Programmable 0–24V output stage with analog-set VOUT and ILIM via ISET and IMON. Use Value: Single-resistor VOUT programming and 1/40,000 current mirroring enable precise, low-cost analog control-no DAC or shunt required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3649EUFD#PBF | Same die, 28-lead 4mm × 5mm QFN package with θJA = 43°C/W; higher thermal resistance than TSSOP; different pinout layout. | Preferred where PCB area is constrained and thermal vias can be deployed; less suitable for manual rework or wave soldering. | Select LTC3649EFE#PBF for ease of assembly, thermal reliability in airflow-limited enclosures, and compatibility with legacy TSSOP footprints. |
| LM5164QPWPRQ1 | 42V max input, 0.5A output, no integrated current monitor or VINREG; requires external compensation and sense resistor for current limiting. | Targeted at lower-power automotive infotainment; lacks rail-to-rail output, programmable frequency, and IMON functionality. | Choose LTC3649EFE#PBF when 4A output, 60V rating, lossless current monitoring, or MPPT capability are required. |
Compared with LTC3649EUFD#PBF, the LTC3649EFE#PBF offers superior thermal performance in convection-cooled industrial designs and simplified assembly, while LM5164QPWPRQ1 lacks critical features like integrated current sensing and input voltage regulation-making LTC3649EFE#PBF the only option meeting full functional and parametric requirements.
Availability
LTC3649EFE#PBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, solar charge controllers, and programmable test equipment requiring stable component supply across extended temperature ranges (–40°C to 125°C).
Supply support for LTC3649EFE#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 LTC3649 belongs to Linear's monolithic high-voltage buck regulator product line, designed specifically for rugged, high-efficiency DC/DC conversion in environments demanding wide input range, precision regulation, and integrated protection features.
FAQ
What is the maximum input voltage rating for the LTC3649EFE#PBF?
The LTC3649EFE#PBF has an absolute maximum input voltage rating of 64V, with guaranteed operation from 3.1V to 60V. Its VIN overvoltage protection activates at 68V (rising) with 4V hysteresis, suspending switching and discharging ISET to protect internal MOSFETs-critical for automotive load-dump survival and industrial surge immunity.
How does the LTC3649EFE#PBF achieve accurate output voltage programming without trimming?
The LTC3649EFE#PBF uses a precision 50µA current source at the ISET pin, enabling VOUT = 50µA × RSET with ±0.8% total accuracy over line, load, and temperature. This eliminates potentiometers or DACs-RSET tolerances dominate final accuracy, and soft-start is added via capacitor from ISET to SGND.
Can the LTC3649EFE#PBF operate in dropout mode, and what limits its minimum input voltage?
The LTC3649EFE#PBF supports high-duty-cycle operation down to VIN ≈ VOUT + 0.5V, but full dropout is limited by two factors: (1) ISET current accuracy degrades when VISET approaches VIN within ~300mV, and (2) BOOST capacitor refresh requires periodic bottom-FET conduction. For true dropout, drive ISET with an external stable reference.
What is the purpose of the IMON pin on the LTC3649EFE#PBF, and how is it used for current limiting?
The IMON pin on the LTC3649EFE#PBF outputs a 1/40,000-scale replica of average inductor current (±4% accuracy). When voltage across RIMON exceeds 2V, the regulator limits peak inductor current-enabling programmable average output current limit: ILAVG = 80mA × (2V / VIMON). No sense resistor is needed.
Does the LTC3649EFE#PBF require external compensation components?
No-the LTC3649EFE#PBF features internal compensation. Connecting ITH to INTVCC activates this mode, eliminating external Type-II or Type-III compensation networks. External compensation is optional via ITH for custom loop shaping, but not required for stable operation across its full VOUT/IOUT range.
LTC3649EFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm 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):
- 3.1V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 0V
- Voltage - Output (Max):
- 55V
- Current - Output:
- 4A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LTC3649EFE#PBF FAQ
1.How can I place an order for LTC3649EFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3649EFE#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 LTC3649EFE#PBF reliable?
The price and inventory of LTC3649EFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3649EFE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3649EFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3649EFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3649EFE#PBF?
LTC3649EFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3649EFE#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 LTC3649EFE#PBF?
For technical support, including LTC3649EFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3649EFE#PBF requirements.
6.How does Aetrix verify that LTC3649EFE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3649EFE#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 LTC3649EFE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3649EFE#PBF?
All LTC3649EFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3649EFE#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 LTC3649EFE#PBF part is unused and in its original packaging.
Return procedure for LTC3649EFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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