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Analog Devices Inc. LTC3649EFE#TRPBF
- Part No.:
- LTC3649EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3649EFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 4A 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,525
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Product details
Overview
LTC3649EFE#TRPBF 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, 440µA regulated quiescent current, and supports programmable switching frequency from 300kHz to 3MHz - used in industrial power supplies requiring wide input range and precise current monitoring.
For engineers reviewing the LTC3649EFE#TRPBF datasheet, LTC3649EFE#TRPBF pinout, LTC3649EFE#TRPBF application, or LTC3649EFE#TRPBF equivalent, key selection criteria include its 60V max input rating, integrated 110mΩ/50mΩ MOSFETs, accurate resistor-programmable output voltage (via 50µA ISET bias), input voltage regulation for MPPT, and Burst Mode®/forced continuous mode selection via MODE/SYNC pin.
Technical Context
The LTC3649EFE#TRPBF employs a peak current mode architecture with inherent cycle-by-cycle current limiting and fast transient response. Its error amplifier uses internal compensation (ITH tied to INTVCC) and supports soft-start via ISET capacitor.
It integrates dual LDOs: one powered from VIN (3.3V INTVCC), another from EXTVCC (3.1V INTVCC) when VIN > 5V and EXTVCC > 3.2V - enabling reduced power loss at high input voltages. Input voltage regulation (VINREG) and cable drop compensation are implemented using resistor dividers and IMON feedback without external sense resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.1V to 60V - supports automotive cold-crank, industrial 48V bus, and solar MPPT inputs. |
| Output Current | Up to 4A - delivered continuously with thermal management via exposed pad (Pin 29). |
| Output Voltage Range | 0V to (VIN – 0.5V) - enables true rail-to-rail adjustment including zero-VOUT operation. |
| Switching Frequency | 300kHz to 3MHz (RT-programmable) - allows optimization of size vs. efficiency; ±50% sync range for external clock locking. |
| Quiescent Current | 440µA (regulated IQ) / 18µA (shutdown) - enables low-power standby in battery-backed systems. |
| Current Monitoring Accuracy | ±4% without sense resistor - IMON pin outputs 1/40,000× IOUT for precision load telemetry and overcurrent protection. |
| Output Voltage Accuracy | ±0.8% - ensures stable reference for sensitive analog or FPGA core rails. |
Pinout & Package
Package: 28-Lead Plastic TSSOP (FE package), thermally enhanced with exposed SGND pad (Pin 29) requiring PCB soldering for electrical and thermal performance. θJA = 30°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGND (Pins 1–5) | Power ground return for high-current switch paths | Must be low-inductance connection to minimize noise and ensure stable current sensing. |
| VIN (Pins 6, 7) | Main input supply for regulator and internal LDOs | Accepts 3.1V–60V; includes OVP (64V trip) and UVLO (2.65V rising threshold). |
| RUN (Pin 8) | Logic-controlled enable with hysteresis | 1.2V rising / 1.08V falling threshold; resistor divider from VIN sets precise undervoltage turn-on point. |
| MODE/SYNC (Pin 10) | Mode selection and oscillator synchronization | GND = Burst Mode®; floating = forced continuous; external clock = sync + FC mode. |
| IMON (Pin 13) | Average output current monitor output | 1/40,000× IOUT - enables resistor-based current limit programming and cable drop compensation. |
| VINREG (Pin 14) | Input voltage regulation sense input | 2.0V threshold - used for MPPT or hold-up by reducing peak current when VIN drops below setpoint. |
| RT (Pin 15) | Oscillator frequency programming | 33.3kΩ–333.3kΩ resistor sets fSW from 3MHz–300kHz; defines ±50% sync window. |
| ISET (Pin 17) | 50µA reference current source and EA+ input | VOUT = 50µA × RSET - single-resistor output programming with ±0.8% accuracy. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail output programmability | VOUT adjustable from 0V to (VIN – 0.5V) using single resistor on ISET - eliminates need for external DAC or feedback divider tuning. |
| Accurate current monitoring without sense resistor | ±4% IMON accuracy enables real-time load telemetry and programmable current limiting (ILIM = 2V × 40,000 / RIMON). |
| Input voltage regulation loop | VINREG pin triggers automatic current reduction at 2.0V threshold - supports MPPT algorithms and momentary input hold-up. |
| Thermally optimized TSSOP package | 28-lead FE package with exposed SGND pad (Pin 29) achieves θJA = 30°C/W - enables 4A operation without heatsink in compact layouts. |
| Burst Mode® and forced continuous modes | Configurable via MODE/SYNC pin - Burst Mode® delivers >90% efficiency at light loads; FC mode ensures low ripple for noise-sensitive analog circuits. |
Applications
| Industrial Power Supplies | Automotive DC-DC Conversion |
|---|---|
Use Scenario: 24V/48V industrial bus powering PLC I/O modules with variable load profiles. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering stable 3.3V/5V/12V rails with input surge tolerance up to 60V. Use Value: Wide VIN range handles brownouts and transients; ±0.8% VOUT accuracy ensures reliable digital logic operation across temperature. | Use Scenario: Start-stop vehicle system converting 12V battery (6V–16V) to 5V for infotainment MCU and sensors. IC Role / Device Role / Timing Role: High-efficiency step-down regulator with Burst Mode® for ultra-low IQ during engine-off periods. Use Value: 18µA shutdown IQ extends battery life; VIN undervoltage programming prevents MCU reset during cranking. |
| Solar MPPT Charge Controllers | Programmable Test Equipment Power |
Use Scenario: PV array interface where input voltage varies 20V–60V and output must track maximum power point. IC Role / Device Role / Timing Role: Regulator with VINREG feedback loop acting as analog MPPT controller by regulating input current. Use Value: Input voltage regulation loop maintains constant VIN at 2.0V reference - enables simple, cost-effective MPPT without microcontroller. | Use Scenario: Bench power supply module with digitally adjustable output (0–24V) and current limiting for lab use. IC Role / Device Role / Timing Role: Programmable buck controller with ISET-based VOUT and IMON-based current limit. Use Value: Single-resistor VOUT programming and 1/40,000-scale IMON allow precise, drift-free voltage/current setting without calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3649IUFD#TRPBF | Same die, 28-lead QFN (UFD) package with θJA = 43°C/W; identical electrical specs and pinout except PGND/SGND layout. | Higher thermal resistance requires more PCB copper area for 4A operation; better suited for space-constrained layouts needing lower profile. | Select when board layout favors QFN thermal vias and footprint density over TSSOP ease of rework. |
| LT8640SIV#TRPBF | 42V max VIN, 4A, Silent Switcher® architecture; 2.5µA IQ in shutdown, integrated ferrite bead filter; no ISET-based VOUT programming. | Lacks rail-to-rail VOUT and VINREG functionality; superior EMI performance but requires feedback resistor network. | Choose for ultra-low-noise applications (e.g., RF systems) where 60V VIN and MPPT are not required. |
Compared with LTC3649IUFD#TRPBF, the LTC3649EFE#TRPBF offers lower thermal resistance in TSSOP form for easier hand-soldering and rework, while LT8640SIV#TRPBF trades off input voltage range and analog programmability for best-in-class EMI suppression and sub-3µA shutdown IQ.
Availability
LTC3649EFE#TRPBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive DC-DC conversion, and solar MPPT charge controllers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC3649EFE#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) is a global leader in high-performance analog, mixed-signal, and power management ICs, serving industrial, automotive, communications, and aerospace markets.
The LTC3649 belongs to Linear's monolithic high-voltage buck regulator product line, designed specifically for rugged, wide-input industrial and automotive power conversion where programmability, accuracy, and reliability are critical.
FAQ
What is the maximum input voltage rating for the LTC3649EFE#TRPBF?
The LTC3649EFE#TRPBF has an absolute maximum input voltage rating of 64V, with recommended operating range from 3.1V to 60V. It includes internal overvoltage lockout that suspends switching when VIN exceeds 68V (rising threshold), protecting the integrated 110mΩ top MOSFET and internal circuitry. This makes LTC3649EFE#TRPBF suitable for 48V industrial buses and automotive load-dump scenarios.
How is the output voltage programmed on the LTC3649EFE#TRPBF?
The LTC3649EFE#TRPBF uses a precision 50µA current source on the ISET pin to program VOUT via a single resistor to SGND: VOUT = 50µA × RSET. This architecture provides ±0.8% output accuracy and eliminates feedback resistor networks. For example, a 100kΩ resistor sets VOUT = 5.0V. The LTC3649EFE#TRPBF also supports rail-to-rail adjustment down to 0V and up to (VIN – 0.5V), enabled by this direct ISET bias method.
Does the LTC3649EFE#TRPBF support current limiting without an external sense resistor?
Yes, the LTC3649EFE#TRPBF provides accurate output current limiting without any external sense resistor. Its IMON pin delivers a current equal to IOUT / 40,000. By connecting a resistor RIMON from IMON to GND, the resulting voltage (VIMON = IOUT × RIMON / 40,000) is compared internally to a 2.0V threshold. When exceeded, the LTC3649EFE#TRPBF reduces peak inductor current to enforce ILAVG = 80A × RIMON (in kΩ). This feature is confirmed in the Electrical Characteristics table (AIMON = 40k, IIMON = 100µA at 4A).
What thermal considerations apply to the LTC3649EFE#TRPBF in TSSOP package?
The LTC3649EFE#TRPBF in 28-lead TSSOP (FE) package has θJA = 30°C/W and requires soldering of the exposed SGND pad (Pin 29) to a thermal plane for rated performance. At 4A output and 24V input, typical power dissipation is ~1.2W; with ambient at 85°C, junction temperature reaches ~125°C without additional copper. Layout must include ≥4 thermal vias under the pad connected to inner-layer ground planes. Unlike the QFN variant, the TSSOP's lower thermal resistance simplifies thermal design in manually assembled prototypes.
Can the LTC3649EFE#TRPBF synchronize its switching frequency to an external clock?
Yes, the LTC3649EFE#TRPBF supports external clock synchronization via the MODE/SYNC pin. When an external clock signal is applied, the internal oscillator locks to it within ±50% of the RT-programmed frequency. For example, if RT sets fSW = 1MHz, the external clock must be between 500kHz and 1.5MHz for reliable lock. During sync, the device operates in forced continuous mode. This capability is verified in the Electrical Characteristics table (fSYNC capture range = 50% to 150% of programmed frequency).
LTC3649EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm 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):
- 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#TRPBF FAQ
1.How can I place an order for LTC3649EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3649EFE#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 LTC3649EFE#TRPBF reliable?
The price and inventory of LTC3649EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3649EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3649EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3649EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3649EFE#TRPBF?
LTC3649EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3649EFE#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 LTC3649EFE#TRPBF?
For technical support, including LTC3649EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3649EFE#TRPBF requirements.
6.How does Aetrix verify that LTC3649EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3649EFE#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 LTC3649EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3649EFE#TRPBF?
All LTC3649EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3649EFE#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 LTC3649EFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3649EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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