My Inquiry
My Account
Analog Devices Inc. LTC3649IUFD#PBF
- Part No.:
- LTC3649IUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3649IUFD#PBF.pdf
- Description:
- IC REG BUCK ADJ 4A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:526
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3649IUFD#PBF from Analog Devices is a 60V, 4A synchronous monolithic step-down regulator with rail-to-rail programmable output (0V to VIN – 0.5V), single-resistor VOUT programming, and peak current mode control. It delivers up to 4A at 5V from 12V input with 95% efficiency, supports 300kHz–3MHz switching frequency via RT resistor, and features ±0.8% output voltage accuracy and integrated 110mΩ/50mΩ MOSFETs. Used in industrial power supplies requiring wide-input, high-current DC/DC conversion.
For engineers reviewing the LTC3649IUFD#PBF datasheet, LTC3649IUFD#PBF pinout, LTC3649IUFD#PBF application, or LTC3649IUFD#PBF equivalent, key selection criteria include its 60V max input, programmable current limit, accurate IMON-based current monitoring (±4%), Burst Mode® vs forced continuous mode trade-off, and thermally enhanced 28-lead 4mm × 5mm QFN package with exposed SGND pad.
Technical Context
The LTC3649IUFD#PBF employs a peak current mode architecture with internal compensation, enabling fast transient response and inherent cycle-by-cycle current limiting. Its error amplifier adjusts ITH voltage to regulate output by comparing VOUT against the 50µA-biased ISET reference, supporting rail-to-rail output from 0V to (VIN – 0.5V).
It integrates dual N-channel MOSFETs (110mΩ top / 50mΩ bottom), supports input voltage regulation for MPPT applications via VINREG pin (2.0V threshold), and enables cable drop compensation using IMON feedback into ISET. MODE/SYNC pin selects Burst Mode® (high light-load efficiency) or forced continuous mode (low ripple), and allows external clock synchronization within ±50% of programmed fSW.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.1V to 60V - supports automotive cold-crank, industrial 48V bus, and wide-range off-line inputs. |
| Output Current | Up to 4A - delivered continuously with thermal management via exposed QFN pad. |
| Output Voltage Range | 0V to (VIN – 0.5V) - enables true rail-to-rail adjustment including zero-VOUT capability. |
| Switching Frequency | 300kHz to 3MHz - set by RT resistor; ±50% sync range allows precise external clock locking. |
| Efficiency | 95% at 12VIN/5VOUT/4A - achieved via low RDS(ON) MOSFETs and optimized gate drive. |
| Quiescent Current | 440µA in regulation, 18µA in shutdown - enables battery-backed or always-on systems. |
| Current Monitoring Accuracy | ±4% without sense resistor - IMON pin outputs 1/40,000× IOUT, enabling precision load telemetry. |
| Output Voltage Accuracy | ±0.8% - ensures stable reference for sensitive analog or digital loads. |
Pinout & Package
The LTC3649IUFD#PBF is housed in a thermally enhanced 28-lead (4mm × 5mm) plastic QFN package with exposed SGND pad (Pin 29) that must be soldered to PCB ground for electrical integrity and thermal performance (θJA = 43°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGND (Pins 1, 2, 26–28) | Power Ground | Low-inductance return path for high-current switch node; connects directly to exposed pad. |
| VIN (Pins 3, 4) | Main Input Supply | Accepts 3.1V–60V; powers internal regulators and high-side MOSFET driver. |
| RUN (Pin 5) | Enable Control | Logic input with 1.2V rising threshold; resistor divider from VIN sets precise undervoltage lockout. |
| SGND (Pins 6, 29) | Signal Ground | Reference for error amp, ISET, IMON, and feedback; tied to exposed pad for noise immunity. |
| MODE/SYNC (Pin 7) | Operating Mode Select | GND = Burst Mode®; floating = forced continuous; external clock = synchronized CCM. |
| PGOOD (Pin 8) | Power Good Indicator | Open-drain output asserting when VPGFB is between 0.555V and 0.645V (10mV hysteresis). |
| PGDFB (Pin 9) | Power Good Feedback | Connects to resistor divider from VOUT to set PGOOD trip point. |
| IMON (Pin 10) | Current Monitor Output | Sinks 1/40,000× average IOUT; enables resistor-based current sensing or regulation. |
| VINREG (Pin 11) | Input Voltage Regulation Sense | Resistor divider from VIN sets 2.0V regulation threshold for MPPT or hold-up operation. |
| RT (Pin 12) | Frequency Programming | Resistor to GND sets fSW from 300kHz to 3MHz; defines ±50% sync window. |
| VOUT (Pin 13) | Error Amplifier Inverting Input | Connected to output node; forms feedback loop with ISET reference. |
| ISET (Pin 14) | Output Voltage Reference | 50µA sink; RSET to SGND programs VOUT = 50µA × RSET. |
| ITH (Pin 15) | Compensation Node | Error amp output; ties to INTVCC for internal compensation; sets peak current threshold. |
| EXTVCC (Pin 16) | External Bias Supply | Accepts 3.2V–28V; powers INTVCC LDO to reduce dissipation when VIN > 5V. |
| INTVCC (Pin 17) | Internal LDO Output | 3.3V (VIN-powered) or 3.1V (EXTVCC-powered); bypass with ≥2.2µF ceramic capacitor. |
| BOOST (Pin 18) | Bootstrap Supply | Drives high-side MOSFET gate; requires 0.1µF capacitor to SW. |
| SW (Pins 19–25) | Switch Node | Connects to inductor; carries high di/dt switching current; shared across 7 pins for low impedance. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail output programming | VOUT adjustable from 0V to (VIN – 0.5V) using single resistor on ISET, enabling zero-VOUT biasing and dynamic headroom control. |
| Accurate current monitoring without sense resistor | IMON pin provides ±4% accurate 1/40,000× scaling of average output current, eliminating PCB area and power loss from external shunt. |
| Programmable input voltage regulation | VINREG pin accepts resistor divider to enforce 2.0V threshold, allowing MPPT tracking or momentary input hold-up by reducing IOUT during VIN droop. |
| Burst Mode® and forced continuous mode | MODE/SYNC pin selects light-load efficiency optimization (Burst Mode® IQ < 400µA) or low-noise operation (CCM, negative inductor current allowed). |
| Integrated MOSFETs with thermal enhancement | 110mΩ top / 50mΩ bottom N-channel switches in 4mm × 5mm QFN with exposed SGND pad ensure high power density and reliable 4A delivery. |
| Cable drop compensation | Combines IMON current feedback with ISET programming to dynamically raise VOUT proportional to IOUT × RCABLE, maintaining regulated voltage at remote load. |
Applications
| Industrial Power Supplies | Automotive Infotainment Systems |
|---|---|
Use Scenario: 24V vehicle battery powers 5V/4A logic rails for head unit processors and display controllers under varying load and temperature. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering regulated 5V from 6V–36V automotive input with overvoltage protection and thermal robustness. Use Value: 95% efficiency at full load reduces thermal stress; ±0.8% VOUT accuracy ensures stable SoC operation; 60V absolute max rating withstands load dump transients. | Use Scenario: 48V telecom or industrial bus stepped down to 3.3V/4A for FPGA, ADC, and interface ICs in harsh environments. IC Role / Device Role / Timing Role: High-voltage, high-current DC/DC converter providing isolated, low-noise supply with programmable current limit and fault reporting. Use Value: Rail-to-rail VOUT range supports multiple output voltages from one design; IMON-based current telemetry enables real-time load diagnostics. |
| Solar MPPT Charge Controllers | Test & Measurement Equipment |
Use Scenario: PV panel output (up to 60V) regulated to charge 12V/24V battery banks while maximizing power extraction via input voltage regulation. IC Role / Device Role / Timing Role: Buck converter with VINREG feedback loop acting as programmable input voltage clamp for MPPT algorithm implementation. Use Value: VINREG pin senses input divider to maintain fixed 2.0V reference, enabling precise input voltage regulation without external op-amp or controller. | Use Scenario: Bench power supply module requiring low-noise, digitally programmable 0–24V output with current limiting and telemetry for lab instrumentation. IC Role / Device Role / Timing Role: Programmable step-down regulator with ISET-based VOUT tuning, IMON-based current readback, and soft-start via CSET. Use Value: Single-resistor VOUT programming simplifies calibration; ±4% current monitoring enables accurate load profiling; Burst Mode® extends standby runtime. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3649EUFD#PBF | Same silicon, rated for –40°C to 85°C junction temperature (vs –40°C to 125°C for LTC3649IUFD#PBF). | Suitable for commercial/industrial ambient conditions where extended temperature operation is not required. | Select when full industrial temperature range is unnecessary and cost optimization is prioritized. |
| LT8640SIV#PBF | 42V max input, 4A output, Silent Switcher® architecture; lower EMI, but no rail-to-rail VOUT or IMON current monitoring. | Better for noise-sensitive applications (e.g., RF, medical), but lacks input voltage regulation and cable compensation features. | Choose when ultra-low EMI is critical and MPPT/cable compensation are not needed. |
Compared with LTC3649EUFD#PBF, the LTC3649IUFD#PBF guarantees full –40°C to 125°C operation and tighter parametric limits; versus LT8640SIV#PBF, it offers wider input range, rail-to-rail output, and integrated current monitoring-but with higher radiated emissions due to non-Silent Switcher topology.
Availability
LTC3649IUFD#PBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive infotainment systems, and solar MPPT charge controllers requiring stable component supply, long-term lifecycle support, and guaranteed extended temperature performance.
Supply support for LTC3649IUFD#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 LTC3649IUFD#PBF belongs to Linear's monolithic high-voltage buck regulator product line, designed specifically for rugged, high-efficiency DC/DC conversion in space-constrained industrial and automotive applications with demanding input voltage and thermal requirements.
FAQ
What is the maximum input voltage rating for the LTC3649IUFD#PBF?
The LTC3649IUFD#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 transients. This makes the LTC3649IUFD#PBF suitable for 48V industrial buses and automotive applications subject to load dump events.
How does the LTC3649IUFD#PBF achieve rail-to-rail output voltage programming?
The LTC3649IUFD#PBF achieves rail-to-rail output programming (0V to VIN – 0.5V) via its precision 50µA current source on the ISET pin. Connecting a resistor RSET from ISET to SGND sets VOUT = 50µA × RSET. The architecture supports zero-volt output by pulling ISET to ground, and maintains regulation up to VIN minus the top MOSFET's conduction drop (~0.5V). This eliminates need for external DACs or complex feedback networks in the LTC3649IUFD#PBF design.
Can the LTC3649IUFD#PBF monitor output current without an external sense resistor?
Yes, the LTC3649IUFD#PBF provides accurate output current monitoring without an external sense resistor via its IMON pin, which sinks a current equal to 1/40,000× the average output current (±4% accuracy). Placing a resistor RIMON from IMON to SGND generates VIMON = IOUT × RIMON/40,000, enabling direct voltage-based current readback. This feature is integral to the LTC3649IUFD#PBF and requires no additional components for basic telemetry.
What thermal considerations apply to the LTC3649IUFD#PBF in 4A operation?
The LTC3649IUFD#PBF uses a 28-lead 4mm × 5mm QFN package with an exposed SGND pad (Pin 29) that must be soldered to a minimum 200mm² copper thermal pad on the PCB. With θJA = 43°C/W, sustained 4A operation at high VIN/VOUT differentials requires adequate copper area and airflow. For example, at 24VIN/5VOUT, power dissipation is ~1.2W; a 40°C rise above ambient requires ≤33°C/W total thermal resistance - achievable with 2oz copper, thermal vias, and moderate airflow. This thermal design is essential for reliable LTC3649IUFD#PBF operation.
Does the LTC3649IUFD#PBF support synchronization to an external clock?
Yes, the LTC3649IUFD#PBF 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 frequency set by the RT resistor. During sync, the device operates in forced continuous mode. This capability allows deterministic switching timing in noise-sensitive systems and EMI reduction through frequency dithering - a core timing feature of the LTC3649IUFD#PBF.
LTC3649IUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN 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-QFN (4x5)
LTC3649IUFD#PBF FAQ
1.How can I place an order for LTC3649IUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3649IUFD#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 LTC3649IUFD#PBF reliable?
The price and inventory of LTC3649IUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3649IUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3649IUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3649IUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3649IUFD#PBF?
LTC3649IUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3649IUFD#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 LTC3649IUFD#PBF?
For technical support, including LTC3649IUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3649IUFD#PBF requirements.
6.How does Aetrix verify that LTC3649IUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3649IUFD#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 LTC3649IUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3649IUFD#PBF?
All LTC3649IUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3649IUFD#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 LTC3649IUFD#PBF part is unused and in its original packaging.
Return procedure for LTC3649IUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3649IUFD#PBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
