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Analog Devices Inc. LT1765EFE-5#PBF
- Part No.:
- LT1765EFE-5#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1765EFE-5#PBF.pdf
- Description:
- IC REG BUCK 5V 3A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:285
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Product details
Overview
LT1765EFE-5#PBF from Analog Devices (formerly Linear Technology) is a monolithic 3A, 1.25MHz current-mode step-down switching regulator with fixed 5V output, integrated 0.09Ω NPN power switch, and thermally enhanced 16-lead TSSOP package. It operates from 3V to 25V input, delivers up to 3A continuous output, and maintains constant maximum switch current across all duty cycles-ideal for compact, high-efficiency DC/DC conversion in battery-powered and distributed power systems.
For engineers reviewing the LT1765EFE-5#PBF datasheet, LT1765EFE-5#PBF pinout, LT1765EFE-5#PBF application, or LT1765EFE-5#PBF equivalent, key selection considerations include its fixed 5V feedback reference (4.9V–5.1V), 15μA shutdown current, 1.25MHz switching frequency with external synchronization up to 2MHz, thermal performance enabled by exposed GND pad, and compatibility with ceramic or tantalum output capacitors in space-constrained designs.
Technical Context
The LT1765EFE-5#PBF implements constant-frequency current-mode control using an internal 1.25MHz oscillator, cycle-by-cycle peak current sensing, and a transconductance error amplifier (850μMho) referenced to a 1.2V internal bandgap. Its bipolar NPN switch architecture requires BOOST pin voltage ≥ VIN + 1.8V for saturation, enabling high efficiency despite wide input range (3V–25V).
It integrates undervoltage lockout (2.47V–2.73V), thermal shutdown, and full-cycle current limiting with foldback below 0.5V FB. The VC pin serves dual roles: error amplifier output and current clamp input (0.4V–0.9V operating range), allowing loop compensation and overcurrent override without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±2% (4.9V–5.1V); eliminates external feedback divider and improves accuracy/stability. |
| Max Output Current | 3A continuous; limited by constant 3A–4A switch current rating independent of duty cycle. |
| Switch On Resistance | 0.09Ω typical; enables >90% efficiency at 3A with low conduction loss and minimal thermal rise. |
| Switching Frequency | 1.25MHz typical (1.1–1.6MHz); allows use of small chip inductors (e.g., 1.5μH–2.2μH) and reduces EMI filtering burden. |
| Quiescent Supply Current | 1mA typical; minimizes no-load power loss in always-on or low-duty-cycle applications. |
| Shutdown Current | 15μA typical; extends battery life in portable systems during sleep mode. |
| Input Voltage Range | 3V to 25V; supports Li-ion batteries (3V–4.2V), 5V/12V rails, and 24V industrial inputs without external regulators. |
| Synchronization Range | 1.6MHz to 2MHz; enables EMI reduction via fixed-frequency coordination with system clock or other converters. |
Pinout & Package
LT1765EFE-5#PBF uses a 16-lead thermally enhanced plastic TSSOP package with exposed GND pad (Pin 17) soldered to a large copper plane for θJC(PAD) = 10°C/W. Package dimensions: 5mm × 4.4mm × 1.2mm. Thermal performance relies on PCB copper area under Pin 17 and short GND traces.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 8, 10, 16) | Power and signal reference ground | Must connect all GND pins and exposed pad to single low-impedance ground plane; critical for load regulation, thermal dissipation, and noise immunity. |
| BOOST (Pin 2) | Switch driver boost supply | Requires external capacitor/diode network to generate ≥VIN+1.8V; insufficient boost causes switch saturation loss and efficiency drop. |
| VIN (Pins 3, 4) | Input power collector node | Both pins must be shorted on PCB; high di/dt path requiring local 1μF–4.7μF ceramic bypass capacitor near pins. |
| SW (Pins 5, 6) | Switch emitter output | Drives inductor; negative flyback voltage during off-time requires external catch diode (VBR < 0.8V) clamped to GND. |
| NC (Pins 7, 11, 14) | No-connect terminals | Not internally bonded; must remain unconnected or tied to GND per layout best practice-no routing or loading. |
| SYNC (Pin 12) | External oscillator sync input | Logic-compatible (20%–80% duty); drives internal oscillator into 1.6–2MHz range; float or tie to GND if unused. |
| VC (Pin 13) | Error amplifier output / current clamp | 0.4V–0.9V range sets peak switch current; used for compensation (RC network) or fast shutdown (drive to GND). |
| FB (Pin 15) | Feedback sense input | Internally connected to 5V output; no external divider needed-simplifies layout and improves regulation accuracy. |
| SHDN (Pin 15) | Enable/disable control | 1.33V threshold; pull low to shut down (15μA IQ); can implement precise UVLO with external resistor divider. |
Key Features
| Feature | Design Value |
|---|---|
| Thermally enhanced TSSOP-16 with exposed GND pad | Enables 3A operation at ambient temperatures up to 85°C with standard 2oz copper and 1in² thermal pad-no heatsink required. |
| Constant maximum switch current at all duty cycles | Guarantees consistent 3A–4A current limit regardless of input/output voltage ratio-prevents overcurrent during low-VIN/high-duty-cycle conditions. |
| 1.25MHz current-mode architecture with slope compensation | Provides inherent stability, fast transient response (<10μs), and immunity to subharmonic oscillation up to 50% duty cycle. |
| Integrated 1.2V bandgap reference and fixed 5V feedback network | Eliminates external resistors, reduces BOM count, and ensures ±2% output accuracy over –40°C to 125°C junction temperature. |
| Low 15μA shutdown current with accurate 1.33V SHDN threshold | Supports battery cutoff at precise voltage (e.g., 3.75V turn-off via resistor divider), extending runtime and preventing deep discharge. |
| BOOST pin architecture with external capacitor/diode | Allows full NPN switch saturation across full input range (3V–25V), achieving >92% peak efficiency even at 24V→5V conversion. |
Applications
| DSL Modem Power Supply | Portable Computer Core Rail |
|---|---|
Use Scenario: Converts 12V or 19V adapter input to stable 5V for DSL line card PHY, microcontroller, and memory interfaces. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 5V at up to 3A with tight load/line regulation and low ripple. Use Value: High 1.25MHz switching enables small 1.5μH inductor and 2.2μF ceramic output capacitor-reducing board area by >40% vs. lower-frequency alternatives. |
Use Scenario: Powers USB hub controllers, display interface ICs, and embedded peripherals in ultrabooks and tablets from single-cell Li-ion (3.0V–4.2V) or 5V rail. IC Role / Device Role / Timing Role: Efficient step-down converter maintaining 5V output during battery discharge, with 1mA quiescent current preserving standby time. Use Value: 15μA shutdown current and undervoltage lockout (2.6V min) prevent system brownout and extend usable battery capacity by ~12%. |
| Regulated Wall Adapter Interface | Distributed 5V Power Bus |
Use Scenario: Interfaces unregulated 9V–24V wall adapters to deliver clean, low-noise 5V for sensitive analog front-ends and communication modules. IC Role / Device Role / Timing Role: Isolates noisy adapter ripple via high-frequency switching and tight feedback control. Use Value: Synchronization capability (1.6–2MHz) allows alignment with system clock to eliminate beat frequencies and reduce conducted EMI peaks. |
Use Scenario: Provides localized 5V power to multiple subsystems (e.g., sensors, actuators, comms) across industrial PCBs with long trace runs. IC Role / Device Role / Timing Role: Point-of-load regulator minimizing IR drop and improving dynamic response versus centralized 5V distribution. Use Value: Exposed GND pad and low θJC(PAD) = 10°C/W enable reliable 3A delivery even with limited airflow-critical for enclosed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE-5#PBF | Monolithic 3A buck with 3.5V–40V input, 5V fixed output, 2MHz max frequency, and integrated MOSFETs (not bipolar); 28μA IQ. | Higher input voltage support (up to 40V) and better light-load efficiency; lacks BOOST pin complexity but requires higher gate drive voltage margin. | Select when input exceeds 25V or when synchronous rectification (vs. external diode) is preferred for >94% efficiency. |
| TPS54331DR | 3A buck with 3.5V–28V input, adjustable output, 570kHz frequency, external compensation, and MOSFET-based design; 125μA IQ. | Lower switching frequency increases inductor size; no fixed 5V option-requires external resistor divider and adds tolerance error. | Select when cost sensitivity outweighs board area constraints, or when adjustable output (not fixed 5V) is required for future design reuse. |
Compared with LTC3631EMSE-5#PBF and TPS54331DR, the LT1765EFE-5#PBF offers superior thermal performance in TSSOP-16 due to its exposed pad and bipolar switch architecture, tighter fixed-output accuracy (±2% vs. ±3%), and lower shutdown current (15μA vs. 28μA/125μA), making it optimal for space- and battery-limited 5V systems operating up to 25V input.
Availability
LT1765EFE-5#PBF is available at Aetrix Electronics and suitable for DSL modems, portable computers, and regulated wall adapter interfaces requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LT1765EFE-5#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 LT1765 family was designed as monolithic high-current, high-frequency buck regulators targeting compact, efficient point-of-load conversion in battery-powered and distributed power systems-emphasizing thermal robustness, fixed-output precision, and minimal external component count.
FAQ
What is the minimum input voltage required for LT1765EFE-5#PBF to regulate 5V output?
The LT1765EFE-5#PBF has a guaranteed minimum input voltage of 2.6V (typical 2.47V–2.73V) due to internal undervoltage lockout. However, stable 5V regulation requires VIN ≥ VOUT + dropout margin: for 3A load, VIN must exceed ~6.5V to maintain sufficient headroom for the 0.09Ω switch and BOOST circuit. At light loads, regulation is possible down to ~5.5V.
Can LT1765EFE-5#PBF synchronize to an external clock, and what are the requirements?
Yes, the LT1765EFE-5#PBF supports external synchronization via the SYNC pin. It accepts logic-level signals (20%–80% duty cycle) in the 1.6MHz–2MHz range. The SYNC threshold is 1.5V–2.2V, and input resistance is 20kΩ. For reliable locking, the external clock must exceed the device's free-running frequency (1.1–1.6MHz) and exhibit low jitter-no level-shifting is needed for 3.3V or 5V CMOS sources.
Does LT1765EFE-5#PBF require an external catch diode, and what specifications are critical?
Yes, LT1765EFE-5#PBF requires an external Schottky catch diode (e.g., CMDSH-3) connected between SW and GND. Critical specs: reverse voltage rating ≥ VIN(max) = 25V, forward voltage ≤ 0.8V at peak current, and surge current rating ≥ 4A (to handle short-circuit conditions). Low Qrr and fast recovery minimize switching losses and EMI.
How does the BOOST pin function in LT1765EFE-5#PBF, and what components are needed?
The BOOST pin supplies elevated voltage (>VIN + 1.8V) to fully saturate the internal NPN switch. It requires a flying capacitor (0.18μF ceramic) and Schottky diode (e.g., CMDSH-3) connected from BOOST to output. During switch on-time, the capacitor charges to ~VOUT above VIN; insufficient BOOST voltage increases switch VCE and reduces efficiency-especially at low VOUT or high VIN.
Is LT1765EFE-5#PBF RoHS-compliant and lead-free?
Yes, LT1765EFE-5#PBF carries the #PBF suffix, indicating 100% matte tin lead finish and full compliance with RoHS Directive 2011/65/EU and JEDEC J-STD-609. It is qualified for reflow soldering per J-STD-020, with MSL Level 1 rating and peak temperature tolerance up to 260°C.
LT1765EFE-5#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):
- 5V
- 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-5#PBF FAQ
1.How can I place an order for LT1765EFE-5#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1765EFE-5#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-5#PBF reliable?
The price and inventory of LT1765EFE-5#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-5#PBF is usually 5 days.
3.What payment methods are accepted for LT1765EFE-5#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1765EFE-5#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1765EFE-5#PBF?
LT1765EFE-5#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1765EFE-5#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-5#PBF?
For technical support, including LT1765EFE-5#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1765EFE-5#PBF requirements.
6.How does Aetrix verify that LT1765EFE-5#PBF is sourced from the original manufacturer or authorized distributors?
All LT1765EFE-5#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-5#PBF meets industry standards.
7.What is the process for return or replacement of LT1765EFE-5#PBF?
All LT1765EFE-5#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1765EFE-5#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-5#PBF part is unused and in its original packaging.
Return procedure for LT1765EFE-5#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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