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Analog Devices Inc. LT1765EFE-3.3#PBF
- Part No.:
- LT1765EFE-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1765EFE-3.3#PBF.pdf
- Description:
- IC REG BUCK 3.3V 3A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:836
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Product details
Overview
LT1765EFE-3.3#PBF from Analog Devices (formerly Linear Technology) is a monolithic 3A, 1.25MHz current-mode step-down switching regulator with fixed 3.3V output, integrated 0.09Ω NPN power switch, and thermally enhanced 16-lead TSSOP package. It operates from 3V to 25V input, delivers up to 2.5A continuous output, and features 15μA shutdown current - ideal for compact, high-efficiency DC/DC conversion in portable computers and battery-powered systems.
For engineers reviewing the LT1765EFE-3.3#PBF datasheet, LT1765EFE-3.3#PBF pinout, LT1765EFE-3.3#PBF application, or LT1765EFE-3.3#PBF equivalent, key selection criteria include its fixed 3.3V output accuracy (±2%), constant-frequency current-mode control for fast transient response, thermal performance enabled by exposed GND pad, and synchronization capability up to 2MHz for EMI reduction in dense PCB layouts.
Technical Context
The LT1765EFE-3.3#PBF implements a constant-frequency, peak-current-mode buck topology with internal 1.25MHz oscillator, cycle-by-cycle current limiting, and integrated error amplifier (gm = 850μMho). Its BOOST pin drives the NPN switch with voltage > VIN to ensure saturation, enabling high efficiency across 3V–25V input range.
It uses a fixed internal feedback divider for 3.3V output (FB pin tied directly to VOUT), eliminating external resistors. Shutdown threshold is 1.33V with 7μA hysteresis, and SYNC input accepts logic-level signals (20–80% duty cycle) to lock oscillator frequency between 1.6MHz and 2MHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±2% (3.234V to 3.366V) - eliminates external resistor network and improves load regulation stability. |
| Switch Current Limit | 3A typical, 4A min - enables robust 2.5A continuous output under worst-case thermal conditions. |
| Switching Frequency | 1.25MHz typical (1.1–1.6MHz over temp) - allows use of small chip inductors (e.g., 1.5μH) and ceramic capacitors. |
| Input Voltage Range | 3V to 25V - supports Li-ion batteries (3.0–4.2V), 5V/12V rails, and 24V industrial systems without external regulators. |
| Shutdown Current | 15μA typical - extends battery life in standby mode for portable equipment. |
| Feedback Reference | Internally trimmed 1.2V reference - ensures precise 3.3V output via on-die resistor divider (no FB pin external connection required). |
| Thermal Resistance | θJC(PAD) = 10°C/W - requires soldering exposed pad (Pin 17) to large copper plane for reliable 2.5A operation at 125°C junction. |
Pinout & Package
LT1765EFE-3.3#PBF is housed in a 16-lead thermally enhanced plastic TSSOP package with exposed GND pad (Pin 17). The package provides low thermal resistance (θJA = 45°C/W) and requires PCB layout with direct copper connection to the exposed pad for thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 8, 10, 14, 16) | Power and signal reference ground | Multiple GND pins and exposed pad must be connected to a large copper plane to minimize thermal resistance and improve load regulation. |
| VIN (Pins 3, 4) | Input supply and switch collector | Both pins must be shorted on PCB; supplies internal regulator and powers NPN switch - bypass capacitor must be placed adjacent to reduce di/dt-induced voltage spikes. |
| VSW (Pins 5, 6) | Switch emitter node | Drives inductor; swings from ~0V to VIN during operation - requires external catch diode (e.g., CMDSH-3) clamped to GND. |
| BOOST (Pin 2) | Switch driver boost supply | Provides >VIN voltage to saturate NPN switch - typically driven by 0.18μF capacitor + diode from VOUT; minimum headroom 2.7V above VSW. |
| FB (Pin 11) | Feedback input | Tied internally to output for fixed 3.3V version - no external divider needed; enables current-limit foldback if pulled below 0.5V. |
| VC (Pin 12) | Error amplifier output / current comparator input | Used for loop compensation; voltage ranges from 0.4V (light load) to 0.9V (full load); can be driven to GND to force shutdown. |
| SHDN (Pin 13) | Enable/disable control | Logic-compatible input; 1.33V threshold turns device ON; floating or pulled high enables operation; 15μA shutdown current achieved when pulled low. |
| SYNC (Pin 9) | Oscillator synchronization input | Accepts 1.6–2MHz external clock (20–80% duty cycle); reduces EMI by aligning switching edges; must be grounded if unused. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3A, 0.09Ω NPN switch | Enables high-efficiency conversion (≥85% at 2A, VIN=12V→VOUT=3.3V) without external MOSFET or driver complexity. |
| Current-mode control architecture | Delivers fast transient response (<10μs to settle after 1A load step) and inherent cycle-by-cycle overcurrent protection. |
| Thermally enhanced TSSOP-16 with exposed pad | Supports 2.5A continuous output at ambient ≤65°C when mounted on ≥2 sq-in copper area - avoids need for heatsinks in space-constrained designs. |
| Synchronization to 2MHz external clock | Allows EMI-sensitive applications (e.g., RF modules, audio systems) to shift switching noise out of critical bands and simplify filtering. |
| Low 1mA quiescent supply current | Maintains high light-load efficiency (>80% at 10mA output) - critical for always-on subsystems in portable electronics. |
Applications
| DSL Modem Power Supply | Portable Computer Core Rail |
|---|---|
Use Scenario: Providing stable 3.3V rail for DSL line card PHY and microcontroller in space-limited CPE hardware. IC Role / Device Role / Timing Role: Primary step-down regulator converting 5V or 12V board supply to isolated 3.3V domain with tight ripple control. Use Value: 1.25MHz switching enables use of 2.2μF ceramic output capacitor, reducing footprint vs. lower-frequency alternatives requiring bulkier tantalum solutions. |
Use Scenario: Generating 3.3V core voltage for embedded controllers and I/O interfaces in clamshell laptops and tablets. IC Role / Device Role / Timing Role: High-efficiency buck converter operating from single-cell Li-ion (3.0–4.2V) or 5V USB-C PD input. Use Value: 15μA shutdown current extends battery runtime in suspend mode; thermal pad design sustains 2.5A output during CPU burst loads without derating. |
| Regulated Wall Adapter Interface | Battery-Powered Industrial Sensor Node |
Use Scenario: Down-converting unregulated 9–24V wall adapter output to clean 3.3V for MCU, ADC, and wireless transceiver in IoT gateway. IC Role / Device Role / Timing Role: Input-stage DC/DC regulator with wide VIN range and UVLO (2.6V) to prevent brownout during adapter plug/unplug events. Use Value: Constant 3A switch current limit ensures reliable start-up into capacitive loads (e.g., 100μF input filter), avoiding inrush-related failures. |
Use Scenario: Powering ultra-low-power sensor nodes (e.g., temperature/humidity) running on AA/AAA alkaline or Li-SOCl₂ primary cells. IC Role / Device Role / Timing Role: Efficient step-down regulator delivering regulated 3.3V from 4.5–9V battery stack while minimizing quiescent drain. Use Value: 1mA operating supply current and 15μA shutdown current maximize battery service life - validated for >5-year operation in metering applications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3652EMSE-3.3#PBF | 42V max input, 2A output, integrated power MOSFETs, synchronous rectification | Better suited for automotive (42V) or higher-efficiency (>90%) requirements; lacks SYNC pin and exposed thermal pad | Select when input exceeds 25V or synchronous efficiency is mandatory; not drop-in due to different pinout and control scheme |
| TPS54331DR | 28V max input, 3A output, adjustable VOUT (0.8–28V), 570kHz switching, SO-8 package | Lower cost, smaller footprint, but lower switching frequency increases inductor/capacitor size; no exposed thermal pad | Choose for cost-sensitive, non-thermal-critical designs where 570kHz operation is acceptable and external feedback resistors are tolerable |
Compared with LT1765EFE-3.3#PBF, LT3652EMSE-3.3#PBF offers higher input voltage tolerance and synchronous efficiency but sacrifices thermal performance and synchronization flexibility; TPS54331DR reduces BOM count with integrated FETs but trades off switching frequency, thermal capability, and precision fixed-output stability.
Availability
LT1765EFE-3.3#PBF is available at Aetrix Electronics and suitable for DSL modems, portable computers, regulated wall adapters, battery-powered systems, and distributed power architectures requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT1765EFE-3.3#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT1765 product line was designed as monolithic, high-frequency buck regulators targeting space-constrained, thermally demanding applications - emphasizing integration, efficiency, and ease of layout in portable and industrial power systems.
FAQ
What is the maximum continuous output current for LT1765EFE-3.3#PBF?
The LT1765EFE-3.3#PBF delivers up to 2.5A continuous output current under typical thermal conditions (ambient ≤65°C, exposed pad soldered to ≥2 sq-in copper). This is limited by thermal dissipation, not switch current rating - the internal 3A switch remains active, but junction temperature must stay ≤125°C. Derating is required above 65°C ambient.
Does LT1765EFE-3.3#PBF require external feedback resistors?
No. The LT1765EFE-3.3#PBF integrates the feedback resistor divider for fixed 3.3V output; the FB pin is internally connected to VOUT. External resistors are unnecessary and would disrupt regulation. Only the adjustable LT1765 (no suffix) requires external R1/R2.
Can LT1765EFE-3.3#PBF synchronize to an external clock?
Yes. The SYNC pin of LT1765EFE-3.3#PBF accepts logic-level signals (20–80% duty cycle) to lock the internal oscillator between 1.6MHz and 2MHz. This feature reduces EMI in noise-sensitive systems. When unused, SYNC must be grounded to prevent erratic operation.
What is the purpose of the BOOST pin on LT1765EFE-3.3#PBF?
The BOOST pin on LT1765EFE-3.3#PBF supplies a voltage > VIN to the internal NPN switch driver, ensuring full saturation and low conduction loss (270mV typical at 3A). It is typically driven by a 0.18μF capacitor charged via a diode from VOUT - providing ~3.3V headroom above VSW during switch-on time.
How does LT1765EFE-3.3#PBF handle thermal management?
LT1765EFE-3.3#PBF relies on its exposed GND pad (Pin 17) for thermal conduction. With θJC(PAD) = 10°C/W, it requires soldering to a large copper plane (minimum 2 sq-in) and multiple thermal vias to inner ground layers. Without proper pad connection, junction temperature rises rapidly, triggering thermal shutdown at 125°C.
LT1765EFE-3.3#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 25V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 3A
- Frequency - Switching:
- 1.25MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT1765EFE-3.3#PBF FAQ
1.How can I place an order for LT1765EFE-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1765EFE-3.3#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 LT1765EFE-3.3#PBF reliable?
The price and inventory of LT1765EFE-3.3#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1765EFE-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LT1765EFE-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1765EFE-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1765EFE-3.3#PBF?
LT1765EFE-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1765EFE-3.3#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 LT1765EFE-3.3#PBF?
For technical support, including LT1765EFE-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1765EFE-3.3#PBF requirements.
6.How does Aetrix verify that LT1765EFE-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LT1765EFE-3.3#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 LT1765EFE-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LT1765EFE-3.3#PBF?
All LT1765EFE-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1765EFE-3.3#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 LT1765EFE-3.3#PBF part is unused and in its original packaging.
Return procedure for LT1765EFE-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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