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Analog Devices Inc. LT1765EFE#PBF
- Part No.:
- LT1765EFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1765EFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 3A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:794
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Product details
Overview
LT1765EFE#PBF from Analog Devices (formerly Linear Technology) is a monolithic 3A, 1.25MHz current-mode step-down switching regulator in a thermally enhanced 16-lead TSSOP package. It integrates a 0.09Ω NPN power switch, internal bias regulator, and full cycle-by-cycle current control. Designed for high-efficiency DC/DC conversion from 3V–25V input to fixed 5V output, it delivers stable 3A continuous current in portable computers and battery-powered systems.
For engineers reviewing the LT1765EFE#PBF datasheet, LT1765EFE#PBF pinout, LT1765EFE#PBF application, or LT1765EFE#PBF equivalent, key selection factors include its constant 1.25MHz switching frequency, 15μA shutdown current, 1.2V feedback reference, thermal performance with exposed GND pad (θJC = 10°C/W), and synchronization capability up to 2MHz.
Technical Context
The LT1765EFE#PBF implements a constant-frequency, current-mode buck architecture with an internal 1.25MHz oscillator and dual-loop control: an error amplifier sets the peak switch current threshold via the VC pin, while a dedicated current-sense amplifier monitors switch current on a cycle-by-cycle basis. This enables fast transient response and inherent loop stability without external slope compensation under most conditions.
It uses a bipolar NPN power switch driven by a BOOST pin voltage ≥ VIN + 2.7V to ensure saturation, reducing conduction loss. The integrated 1.2V feedback reference supports precise output regulation, and the SHDN pin provides 1.33V UVLO functionality with 7μA hysteresis current for controlled startup sequencing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.25MHz typical; enables use of small chip inductors (e.g., 1.5–4.7μH) and ceramic capacitors, reducing board area and EMI filter size. |
| Max Output Current | 3A continuous; maintained across all duty cycles due to full cycle-by-cycle current limiting, supporting high-power portable loads. |
| Input Voltage Range | 3V to 25V; accommodates Li-ion batteries (3.0–4.2V), 5V/12V/24V rails, and wide-input industrial supplies without external regulators. |
| Feedback Reference | 1.2V nominal; allows precise output setting via external resistor divider; fixed-output variants (e.g., -5) integrate the divider internally. |
| Shutdown Current | 15μA max; minimizes battery drain in standby mode for always-on or low-power IoT endpoints. |
| Thermal Resistance | θJC(PAD) = 10°C/W; requires soldering exposed pad (Pin 17) to large copper plane for reliable 3A operation at 125°C junction temperature. |
| Synchronization Range | 1.6MHz to 2MHz; permits noise-sensitive system-level clock alignment and EMI reduction via external logic-level SYNC signal. |
Pinout & Package
LT1765EFE#PBF is housed in a 16-lead plastic TSSOP with exposed GND pad (Pin 17) for thermal management. Package dimensions: 5mm × 4.4mm × 1.1mm, pitch 0.65mm. Exposed pad must be soldered to ≥200 mm² copper area for θJA ≤ 45°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 8, 10, 16) | Power and signal ground reference | Must connect all GND pins and exposed pad to single low-impedance ground plane; critical for load regulation, thermal dissipation, and noise immunity. |
| VIN (Pins 3, 4) | Input supply and switch collector | Both pins must be shorted on PCB; carries high di/dt switching current-requires local 4.7μF ceramic bypass capacitor placed <2mm away. |
| 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 | Supplies >VIN voltage to saturate NPN switch; requires 0.18μF capacitor and Schottky diode referenced to VOUT or VIN. |
| FB (Pin 11) | Feedback input | Compares output voltage against 1.2V internal reference; for LT1765EFE#PBF (fixed 5V), FB connects directly to output; no external divider needed. |
| SHDN (Pin 14) | Enable/disable control | Logic-high (>1.33V) enables regulation; logic-low disables switch and reduces quiescent current to 15μA; doubles as accurate UVLO input. |
| SYNC (Pin 13) | Oscillator synchronization input | Accepts 1.6–2MHz external clock with 20–80% duty cycle; floats or grounds when unused; eliminates beat frequencies in multi-regulator systems. |
| VC (Pin 12) | Error amplifier output / current limit control | 0.4V–0.9V range reflects load demand; used for loop compensation (capacitor from VC to GND) or external current limiting override. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3A, 0.09Ω NPN switch | Eliminates external MOSFET and gate driver; reduces BOM count and layout complexity while maintaining high efficiency at 3A load. |
| Current-mode control architecture | Provides inherent cycle-by-cycle overcurrent protection and stable loop dynamics without external compensation components in most applications. |
| Thermally enhanced TSSOP-16 with exposed pad | Enables 3A continuous operation at ambient temperatures up to 85°C with minimal heatsinking-critical for space-constrained portable designs. |
| 1.2V precision feedback reference | Supports ±1.5% output accuracy over temperature and line/load; enables robust 5V rail generation for microcontrollers and peripherals. |
| Synchronizable 1.25MHz oscillator | Allows EMI reduction via frequency dithering or system-level clock alignment-essential for compliance in automotive and medical applications. |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Powering core logic and I/O rails in ultrabooks and tablets with Li-ion input (3.0–4.2V). IC Role / Device Role / Timing Role: Primary 5V intermediate bus converter delivering up to 3A to PMICs and USB controllers. Use Value: High 1.25MHz switching enables compact 2.2μH inductor and 2.2μF ceramic output capacitor, reducing solution footprint by >40% vs. lower-frequency alternatives. | Use Scenario: Regulating 5V for wireless sensor nodes powered by 3.6V Li-SOCl₂ primary cells. IC Role / Device Role / Timing Role: Main DC/DC converter enabling long battery life via 1mA operating current and 15μA shutdown mode. Use Value: Low quiescent current extends shelf life; UVLO via SHDN pin prevents deep discharge below 2.6V, preserving cell longevity. |
| Distributed Power | Regulated Wall Adapters |
Use Scenario: Generating local 5V rails in industrial PLC modules fed from 24V backplane. IC Role / Device Role / Timing Role: Point-of-load regulator converting 24V to 5V with high PSRR and fast transient response to digital load steps. Use Value: Constant 3A switch current rating ensures consistent performance across 3V–25V input range-no derating required at 24V input. | Use Scenario: Secondary-side regulation in universal-input AC/DC adapters targeting 5V@3A USB-C PD profiles. IC Role / Device Role / Timing Role: Post-regulator improving line/load regulation and ripple rejection after primary flyback stage. Use Value: Synchronization capability aligns switching frequency with primary controller, minimizing beat frequencies and easing EMI filtering. |
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#PBF | 4A rated, 3MHz switching, integrated MOSFETs, higher IQ (2.5mA), smaller 12-lead MSOP package | Better suited for ultra-compact, high-density layouts where 3MHz enables sub-1μH inductors; less thermally robust at 3A continuous in ambient >70°C | Select LTC3631EMSE#PBF when board area is constrained and input voltage is ≤15V; verify thermal margin with θJA = 65°C/W. |
| TPS54331DR | 3A, 570kHz max frequency, external MOSFETs, 4.5–28V input, 14-pin SOIC, lower cost | Lower switching frequency increases inductor/capacitor size but improves light-load efficiency; lacks SYNC and BOOST pin flexibility | Select TPS54331DR for cost-sensitive industrial supplies where EMI constraints permit lower frequency and layout space allows larger passives. |
Compared with LTC3631EMSE#PBF and TPS54331DR, the LT1765EFE#PBF offers superior thermal performance in high-ambient environments due to its exposed-pad TSSOP package and bipolar switch architecture, while providing precise 1.2V reference accuracy and robust 1.25MHz operation across the full 3V–25V input range-making it optimal for ruggedized portable and distributed power designs.
Availability
LT1765EFE#PBF is available at Aetrix Electronics and suitable for portable computers, battery-powered systems, and distributed power applications requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant lead-free finish.
Supply support for LT1765EFE#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 and maintains full product support, documentation, and manufacturing continuity for the LT® portfolio.
The LT1765 series belongs to Linear's high-current monolithic buck regulator product line, engineered for compact, efficient DC/DC conversion in space- and thermal-constrained applications such as portable computing and battery-operated instrumentation.
FAQ
What is the output voltage of the LT1765EFE#PBF?
The LT1765EFE#PBF is the fixed 5V output variant of the LT1765 family. Its internal feedback divider is trimmed to deliver a nominal 5.0V output with ±1.5% accuracy over temperature and line/load conditions. The FB pin connects directly to the output; no external resistors are required.
Does the LT1765EFE#PBF require an external catch diode?
Yes, the LT1765EFE#PBF requires an external Schottky catch diode (e.g., CMDSH-3) connected between VSW and GND. Because it uses a bipolar NPN switch, the internal parasitic diode cannot handle the reverse recovery stress or forward conduction losses at 3A. The diode must have VBR < 0.8V and ≥4A surge rating for short-circuit robustness.
Can the LT1765EFE#PBF operate from a 3.3V input?
Yes, the LT1765EFE#PBF supports input voltages as low as 3.0V per Absolute Maximum Ratings and Electrical Characteristics tables. At 3.3V input and 5V output, it operates in 100% duty cycle dropout mode-maintaining regulation until VIN drops below ~5.2V (accounting for switch drop and BOOST headroom). Efficiency decreases in dropout, but functionality is preserved.
How is thermal performance managed on the LT1765EFE#PBF?
Thermal performance relies on soldering the exposed GND pad (Pin 17) to ≥200 mm² of internal or external copper plane. With proper layout, θJC(PAD) = 10°C/W enables 3A continuous operation at 125°C junction temperature. Pins 1, 8, 10, and 16 must also connect to the same plane. Avoid thermal isolation-no solder mask over the pad-and use ≥4 thermal vias to inner ground layers.
Is the LT1765EFE#PBF pin-compatible with other LT1765 variants?
Yes, all LT1765 variants-including LT1765EFE#PBF (5V), LT1765EFE-3.3#PBF (3.3V), and LT1765EFE-1.8#PBF (1.8V)-share identical 16-lead TSSOP packaging, pinout, and electrical interface. Only the internal feedback divider differs; FB pin connection and external circuitry remain unchanged across variants, enabling easy voltage scaling in design reuse.
LT1765EFE#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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 25V
- Voltage - Output (Min/Fixed):
- 1.2V
- Voltage - Output (Max):
- 22.5V
- 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#PBF FAQ
1.How can I place an order for LT1765EFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1765EFE#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#PBF reliable?
The price and inventory of LT1765EFE#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#PBF is usually 5 days.
3.What payment methods are accepted for LT1765EFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1765EFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1765EFE#PBF?
LT1765EFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1765EFE#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#PBF?
For technical support, including LT1765EFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1765EFE#PBF requirements.
6.How does Aetrix verify that LT1765EFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT1765EFE#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#PBF meets industry standards.
7.What is the process for return or replacement of LT1765EFE#PBF?
All LT1765EFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1765EFE#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#PBF part is unused and in its original packaging.
Return procedure for LT1765EFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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