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Analog Devices Inc. LTC3649IFE#PBF
- Part No.:
- LTC3649IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3649IFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 4A 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,927
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Product details
Overview
LTC3649IFE#PBF from Analog Devices is a 60V, 4A synchronous monolithic step-down regulator in a 28-lead TSSOP package. It delivers rail-to-rail programmable output (0V to VIN–0.5V), features peak current mode control, ±0.8% VOUT accuracy, and supports programmable switching frequency (300kHz–3MHz) via external RT resistor. Used in industrial power supplies requiring wide input range and precise current monitoring.
For engineers reviewing the LTC3649IFE#PBF datasheet, LTC3649IFE#PBF pinout, LTC3649IFE#PBF application, or LTC3649IFE#PBF equivalent, key selection criteria include its 60V max input rating, integrated 110mΩ/50mΩ MOSFETs, accurate 50µA ISET bias for single-resistor VOUT programming, Burst Mode® vs forced continuous mode trade-off, and input voltage regulation capability for MPPT systems.
Technical Context
The LTC3649IFE#PBF employs a peak current mode architecture with inherent cycle-by-cycle current limiting and fast transient response. Its error amplifier uses ISET as a precision 50µA reference to set VOUT = 50µA × RSET, enabling rail-to-rail output programming without external feedback resistors.
It integrates dual LDOs (VIN- and EXTVCC-powered) for INTVCC regulation, supports cable drop compensation via IMON–ISET coupling, and implements input voltage regulation by sensing VIN through VINREG to maintain 2.0V threshold-critical for photovoltaic MPPT and hold-up applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.1V to 60V - supports automotive cold-crank, industrial 48V rails, and solar array inputs. |
| Output Current | Up to 4A - delivered continuously with thermal management in TSSOP package. |
| VOUT Accuracy | ±0.8% - ensures stable system-level voltage tolerance without trimming. |
| Quiescent Current | 440µA (regulated IQ), 18µA (shutdown) - enables low-power standby operation. |
| Switching Frequency | 300kHz to 3MHz (programmable via RT) - allows optimization of size, efficiency, and EMI. |
| Current Monitoring | ±4% accuracy, no sense resistor - IMON outputs 1/40,000× IOUT for real-time load telemetry. |
| Top/Bottom RDS(on) | 110mΩ / 50mΩ - reduces conduction loss and improves full-load efficiency up to 95%. |
Pinout & Package
Package: 28-Lead Plastic TSSOP (FE), thermally enhanced, –40°C to 125°C operating junction temperature. Exposed pad (Pin 29) is SGND and must be soldered to PCB ground.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGND (Pins 1–5) | Power Ground | Low-impedance return path for high-current switch node; multiple pins minimize IR drop. |
| VIN (Pins 6, 7) | Main Input Supply | Accepts 3.1V–60V; powers internal regulators and top/bottom MOSFET drivers. |
| RUN (Pin 8) | Enable Control | Logic-controlled start-up; 1.2V rising threshold enables precise VIN undervoltage lockout via resistor divider. |
| SGND (Pins 9, 29) | Signal Ground | Reference for error amplifier, ISET, IMON, and VINREG; isolated from PGND for noise immunity. |
| MODE/SYNC (Pin 10) | Operating Mode Select | GND = Burst Mode® (high light-load efficiency); floating = forced continuous (low ripple); external clock = synchronization. |
| PGOOD (Pin 11) | Power Good Indicator | Open-drain output asserts low when VOUT deviates >±1.5% from target (0.555V–0.645V at PGDFB). |
| PGDFB (Pin 12) | Feedback Sense | Connects to resistor divider from VOUT to GND; sets PGOOD trip thresholds. |
| IMON (Pin 13) | Current Monitor Output | Sinks 1/40,000× average IOUT; enables resistor-based current sensing or regulation without shunt. |
| VINREG (Pin 14) | Input Regulation Sense | Monitors VIN via resistor divider; triggers input voltage regulation when voltage drops below 2.0V. |
| RT (Pin 15) | Frequency Programming | Resistor to GND sets fSW from 300kHz to 3MHz; ±50% sync range accommodates external clocks. |
| VOUT (Pin 16) | Error Amp Inverting Input | Connected directly to output; forms closed-loop regulation with ISET reference. |
| ISET (Pin 17) | Precision Reference Input | 50µA sink sets VOUT = 50µA × RSET; also accepts external voltage for rail-to-rail programming. |
| ITH (Pin 18) | Compensation Node | Internal error amp output; ties to INTVCC for automatic compensation; allows external loop tuning. |
| EXTVCC (Pin 19) | External Bias Supply | Accepts 3.2V–28V supply to reduce power loss in high-VIN applications; bypass with ≥1µF. |
| INTVCC (Pin 20) | Internal LDO Output | 3.3V (VIN-powered) or 3.1V (EXTVCC-powered); powers gate drivers; requires ≥2.2µF ceramic bypass. |
| BOOST (Pin 21) | Bootstrap Supply | Drives top N-MOSFET gate; requires 0.1µF capacitor to SW for charge replenishment. |
| SW (Pins 22–28) | Switch Node | High-current connection to inductor; multiple pins reduce parasitic inductance and improve thermal dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail VOUT programming | 0V to (VIN – 0.5V) using single resistor to ISET - eliminates feedback divider, simplifies layout. |
| Accurate current monitoring | ±4% error without external sense resistor - reduces BOM cost and board space while enabling telemetry. |
| Programmable input voltage regulation | 2.0V threshold on VINREG pin - supports MPPT algorithms and momentary input hold-up during transients. |
| Wire drop compensation | Configurable via IMON–ISET coupling - maintains point-of-load voltage accuracy across long PCB traces or cables. |
| Burst Mode® and forced continuous modes | User-selectable via MODE/SYNC pin - balances light-load efficiency (>90% at 10mA) against output ripple (<20mVpp). |
Applications
| Industrial Power Supply | Automotive Infotainment System |
|---|---|
Use Scenario: 24V vehicle battery powers 5V/3.3V subsystems with wide input transients (cold crank to load dump). IC Role / Device Role / Timing Role: Primary DC/DC buck regulator delivering regulated 5V at up to 4A with overvoltage protection and VIN regulation. Use Value: 60V absolute max rating withstands 80V transients; ±0.8% VOUT accuracy ensures SoC and display ICs meet voltage tolerance specs. | Use Scenario: Central head unit supplies power to USB ports, audio codecs, and display controllers under varying engine loads. IC Role / Device Role / Timing Role: Synchronous step-down controller managing dynamic load steps and maintaining low-noise 3.3V rail. Use Value: Burst Mode® operation achieves <400µA quiescent current in sleep mode; IMON enables real-time load diagnostics. |
| Solar MPPT Charge Controller | Programmable Test Equipment |
Use Scenario: PV panel input (15–60V) regulated to fixed 12V/24V battery charging voltage with adaptive input regulation. IC Role / Device Role / Timing Role: Buck converter implementing input voltage regulation loop via VINREG pin to maximize power extraction. Use Value: Programmable 2.0V VINREG threshold enables precise MPPT point tracking; 95% efficiency at 12VIN/5VOUT minimizes thermal stress. | Use Scenario: Bench power supply module with digitally adjustable output voltage and current limit for lab validation. IC Role / Device Role / Timing Role: Precision programmable regulator where VOUT and ILIM are set via DAC-driven ISET and IMON feedback. Use Value: Single-resistor VOUT programming and ±4% current monitoring enable calibrated, repeatable output settings without calibration resistors. |
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; θJA = 43°C/W vs TSSOP's 30°C/W; exposed pad soldered to SGND. | Better thermal performance in high-density layouts; requires different PCB footprint and reflow profile. | Select for higher ambient temperature or higher sustained load conditions where thermal resistance matters. |
| LT8610AEMSE#PBF | 42V max input, 3.5A output, Silent Switcher® architecture; lower EMI, but no IMON, VINREG, or cable compensation. | Lacks input voltage regulation and current monitoring; optimized for noise-sensitive analog/RF systems, not MPPT or telemetry. | Choose when ultra-low EMI and compact solution size outweigh need for telemetry and adaptive regulation. |
Compared with LTC3649EUFD#PBF, the LTC3649IFE#PBF offers lower thermal resistance in TSSOP but requires more PCB area; versus LT8610AEMSE#PBF, it trades EMI performance for comprehensive system-level features like VINREG, IMON, and wire compensation-making it suitable for intelligent power management rather than pure low-noise conversion.
Availability
LTC3649IFE#PBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive infotainment systems, solar MPPT controllers, and programmable test equipment requiring stable component supply across extended temperature ranges.
Supply support for LTC3649IFE#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.
The LTC3649 belongs to Linear's monolithic high-voltage buck regulator product line, designed for rugged industrial, automotive, and renewable energy applications demanding wide VIN range, precision regulation, and integrated system features like current monitoring and input regulation.
FAQ
What is the maximum input voltage rating for the LTC3649IFE#PBF?
The LTC3649IFE#PBF has an absolute maximum input voltage rating of 64V, with recommended continuous operation up to 60V. It includes built-in VIN overvoltage lockout that suspends switching when VIN exceeds 68V (typical), protecting internal MOSFETs from transient spikes. This makes the LTC3649IFE#PBF suitable for 48V industrial buses and automotive applications with load-dump events.
How does the LTC3649IFE#PBF achieve rail-to-rail output voltage programming?
The LTC3649IFE#PBF uses a precision 50µA current source at the ISET pin to set output voltage as VOUT = 50µA × RSET, enabling programming from 0V up to (VIN – 0.5V). Unlike traditional feedback dividers, this method eliminates resistor ratio errors and allows true zero-volt output. The LTC3649IFE#PBF also supports direct voltage injection into ISET for even broader rail-to-rail flexibility.
Can the LTC3649IFE#PBF monitor output current without a sense resistor?
Yes. The LTC3649IFE#PBF provides accurate ±4% current monitoring via the IMON pin, which sinks a current equal to 1/40,000× the average output current. By connecting a resistor from IMON to ground, designers obtain a voltage proportional to IOUT without adding power loss or board space for a shunt. This feature is integral to the LTC3649IFE#PBF's architecture and requires no external calibration.
What is the purpose of the VINREG pin on the LTC3649IFE#PBF?
The VINREG pin on the LTC3649IFE#PBF enables input voltage regulation by sensing VIN through a resistor divider. When the voltage at VINREG falls below 2.0V, the LTC3649IFE#PBF reduces peak inductor current to prevent input droop-critical for MPPT solar chargers and hold-up supplies. If unused, VINREG should be tied to INTVCC to disable the function and avoid interference with normal regulation.
Does the LTC3649IFE#PBF support synchronization to an external clock?
Yes. The MODE/SYNC pin on the LTC3649IFE#PBF accepts an external clock signal to synchronize switching frequency. The device locks to input clocks within ±50% of the frequency set by the RT resistor. During synchronization, the LTC3649IFE#PBF operates in forced continuous mode, ensuring deterministic timing for EMI reduction and multi-phase coordination in complex power systems.
LTC3649IFE#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
LTC3649IFE#PBF FAQ
1.How can I place an order for LTC3649IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3649IFE#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 LTC3649IFE#PBF reliable?
The price and inventory of LTC3649IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3649IFE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3649IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3649IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3649IFE#PBF?
LTC3649IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3649IFE#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 LTC3649IFE#PBF?
For technical support, including LTC3649IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3649IFE#PBF requirements.
6.How does Aetrix verify that LTC3649IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3649IFE#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 LTC3649IFE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3649IFE#PBF?
All LTC3649IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3649IFE#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 LTC3649IFE#PBF part is unused and in its original packaging.
Return procedure for LTC3649IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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