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Analog Devices Inc. LT1765ES8#PBF
- Part No.:
- LT1765ES8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1765ES8#PBF.pdf
- Description:
- IC REG BUCK ADJ 3A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:469
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Product details
Overview
LT1765ES8#PBF from Analog Devices (formerly Linear Technology) is a monolithic 3A, 1.25MHz current-mode step-down switching regulator in an 8-lead SO package. It integrates a 0.09Ω NPN power switch, internal bias regulator, and oscillator, delivering regulated output from 3V–25V input to fixed 5V output with 1.2V feedback reference and 1mA quiescent current. It is used in portable computers and battery-powered systems requiring compact, high-efficiency DC/DC conversion.
For engineers reviewing the LT1765ES8#PBF datasheet, LT1765ES8#PBF pinout, LT1765ES8#PBF application, or LT1765ES8#PBF equivalent, key selection criteria include its 3A switch current limit, 1.25MHz fixed-frequency operation, 15μA shutdown current, thermal performance in SO-8, and compatibility with ceramic input/output capacitors and external boost diode networks.
Technical Context
The LT1765ES8#PBF implements constant-frequency current-mode control using cycle-by-cycle peak current sensing and an internal 1.25MHz oscillator. Its bipolar NPN switch is driven via a BOOST pin that supplies >VIN voltage to ensure saturation, enabling high efficiency across wide input ranges.
It features dual-loop regulation: the error amplifier sets the current-comparator threshold via the VC pin, while the FB pin monitors output voltage against a 1.2V reference. Shutdown is controlled by a 1.33V-threshold comparator on SHDN, and synchronization is supported from 1.6MHz to 2MHz via the SYNC pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Limit | 3A typical; ensures consistent 3A load capability regardless of duty cycle or input voltage |
| Oscillator Frequency | 1.25MHz typical; enables use of small chip inductors (e.g., 1.5–4.7μH) and low-profile ceramics |
| Feedback Reference | 1.2V nominal; allows precise output setting via external resistor divider for adjustable versions |
| Quiescent Current | 1mA typical; improves light-load efficiency in battery-powered applications |
| Shutdown Current | 15μA typical; minimizes standby drain in always-on systems |
| Input Voltage Range | 3V to 25V; supports Li-ion batteries (3.3–4.2V), 5V/12V rails, and 24V industrial inputs |
| Thermal Resistance | θJA = 90°C/W; requires PCB copper area under GND pin for reliable 3A operation at 125°C junction |
Pinout & Package
LT1765ES8#PBF is housed in an 8-lead plastic SO (Small Outline) package with exposed thermal pad connected internally to GND. The package has standard SO-8 footprint, 1.27mm pitch, and is rated for –40°C to +125°C operating junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SYNC) | Synchronization input | Logic-compatible TTL/CMOS input; accepts 1.6–2MHz external clock to align switching frequency |
| 2 (VC) | Error amplifier output / current clamp node | Provides loop compensation point; also serves as current-limit override (0.4V–0.9V range) |
| 3 (FB) | Feedback input | Monitors output via resistive divider; 1.2V reference enables accurate regulation of adjustable outputs |
| 4 (SHDN) | Shutdown control | 1.33V threshold; pull low to disable regulator and reduce supply current to 15μA |
| 5 (BOOST) | Bootstrap drive supply | Accepts externally generated voltage ≥VIN+1.8V to saturate internal NPN switch |
| 6 (VIN) | Main power input | Supplies internal circuitry and collector of NPN switch; requires local 1–4.7μF ceramic bypass |
| 7 (SW) | Switch emitter node | Drives external inductor; swings from ~0V to VIN during operation; requires catch diode clamping |
| 8 (GND) | Power and signal reference | Primary ground return; must connect to large copper area to minimize thermal resistance and improve load regulation |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3A NPN switch | 0.09Ω on-resistance reduces conduction loss and eliminates need for external MOSFET driver |
| Current-mode control | Enables fast transient response and stable loop compensation without complex type-II/III networks |
| BOOST pin architecture | Allows full saturation of internal bipolar switch across wide VIN range, sustaining high efficiency at low VOUT |
| 1.25MHz fixed-frequency operation | Permits use of sub-3mm height chip inductors and <10μF ceramic output caps, reducing board area |
| Thermally enhanced SO-8 | GND pin tied to internal die tab; achieves θJA = 90°C/W with minimal PCB copper, unlike standard SO-8 |
Applications
| DSL Modems | Portable Computers |
|---|---|
Use Scenario: Powering 3.3V or 5V logic, PHY, and memory subsystems from 12V or 19V adapter input in space-constrained DSL gateway designs. IC Role / Device Role / Timing Role: Primary non-isolated buck converter delivering up to 3A continuous output with tight line/load regulation. Use Value: Enables single-stage conversion with no external gate driver, reducing BOM count and layout complexity versus discrete solutions. | Use Scenario: Regulating core voltage for embedded controllers or peripheral interfaces in fanless notebooks and tablets powered by Li-ion batteries. IC Role / Device Role / Timing Role: High-efficiency step-down regulator supporting wide input (3V–25V) and low-quiescent-current sleep modes. Use Value: 1mA operating current and 15μA shutdown extend battery runtime; 1.25MHz switching avoids audible noise in sensitive audio sections. |
| Regulated Wall Adapters | Battery-Powered Systems |
Use Scenario: Secondary-side DC/DC stage in universal-input AC/DC adapters delivering regulated 5V/3A to USB-C PD or legacy 5V loads. IC Role / Device Role / Timing Role: Post-regulator improving transient response and ripple rejection beyond primary-side controller limitations. Use Value: Fixed 5V version (LT1765ES8#PBF) eliminates feedback resistor network, simplifying compliance testing and production calibration. | Use Scenario: Main system power rail in handheld test equipment, medical sensors, or IoT edge nodes operating from 2-cell Li-ion (6–8.4V) or 9V alkaline packs. IC Role / Device Role / Timing Role: High-density buck converter delivering stable 5V output with UVLO protection to prevent deep battery discharge. Use Value: Built-in 2.6V VIN undervoltage lockout prevents brownout-induced firmware corruption and extends usable battery capacity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EDE#PBF | 4A synchronous buck, 3MHz switching, integrated MOSFETs, 2.5V–5.5V input only | Requires lower input voltage; better suited for single-cell Li-ion (2.7–4.2V) or 3.3V system rails | Select when higher efficiency at light loads or smaller inductor size is critical, and input stays below 5.5V |
| TPS54331DR | 3A synchronous buck, 500kHz–2.5MHz programmable frequency, 3.5V–28V input, integrated FETs | Wider input range than LT1765ES8#PBF but lacks BOOST pin; uses MOSFETs instead of bipolar switch | Choose for designs needing adjustable frequency, lower EMI via spread-spectrum option, or simplified boost capacitor elimination |
Compared with LTC3605EDE#PBF and TPS54331DR, the LT1765ES8#PBF offers superior high-VIN efficiency due to its BOOST-driven bipolar switch and maintains constant 3A current limit across all duty cycles-critical for 12V/24V input systems where alternatives may derate.
Availability
LT1765ES8#PBF is available at Aetrix Electronics and suitable for DSL modems, portable computers, and regulated wall adapters requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LT1765ES8#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 continues to manufacture and support its high-performance analog and power management portfolio.
The LT1765 series belongs to Linear's monolithic switching regulator product line, designed specifically for compact, high-current DC/DC conversion in space- and thermal-constrained applications where integration, reliability, and wide input range are essential.
FAQ
What is the maximum output current capability of the LT1765ES8#PBF?
The LT1765ES8#PBF delivers up to 3A continuous output current under typical conditions (e.g., VIN = 12V, VOUT = 5V, TA = 25°C, with adequate PCB copper). Its maximum switch current limit is 3A typical (4A max), and output current is constrained by thermal limits and inductor selection-not by duty cycle. Derating applies above 85°C ambient or with insufficient heatsinking.
Does the LT1765ES8#PBF require an external catch diode?
Yes, the LT1765ES8#PBF requires an external Schottky catch diode (e.g., CMDSH-3) connected between SW and GND. Because it uses an NPN bipolar switch, the internal parasitic diode cannot conduct during off-time. The diode must withstand VIN reverse voltage and handle average current up to ~2.5A (for 5V out at 3A load), with <0.8V forward voltage to avoid excessive losses.
Can the LT1765ES8#PBF be synchronized to an external clock?
Yes, the LT1765ES8#PBF supports synchronization via its SYNC pin. An external logic-level signal (20–80% duty cycle) in the 1.6MHz–2MHz range can lock the internal oscillator. This feature reduces EMI by eliminating beat frequencies and enables multi-rail phase alignment in dense power systems.
What is the purpose of the BOOST pin on the LT1765ES8#PBF?
The BOOST pin on the LT1765ES8#PBF supplies elevated gate drive voltage (>VIN) to fully saturate the internal NPN power switch. It is charged via an external capacitor–diode network (e.g., 0.18μF + CMDSH-3), typically referenced to VOUT. This architecture sustains high efficiency across wide input ranges (3V–25V) and prevents switch degradation at low VOUT.
Is the LT1765ES8#PBF pin-compatible with other variants in the LT1765 family?
Yes, the LT1765ES8#PBF shares identical pinout and package (8-lead SO) with all LT1765-x variants (e.g., LT1765ES8-3.3#PBF, LT1765ES8-5#PBF). Only the internal feedback divider differs-fixed-output versions tie FB directly to VOUT, while the adjustable LT1765ES8#PBF requires external resistors. No PCB change is needed when substituting within the SO-8 family.
LT1765ES8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- 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:
- 8-SO
LT1765ES8#PBF FAQ
1.How can I place an order for LT1765ES8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1765ES8#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 LT1765ES8#PBF reliable?
The price and inventory of LT1765ES8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1765ES8#PBF is usually 5 days.
3.What payment methods are accepted for LT1765ES8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1765ES8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1765ES8#PBF?
LT1765ES8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1765ES8#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 LT1765ES8#PBF?
For technical support, including LT1765ES8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1765ES8#PBF requirements.
6.How does Aetrix verify that LT1765ES8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1765ES8#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 LT1765ES8#PBF meets industry standards.
7.What is the process for return or replacement of LT1765ES8#PBF?
All LT1765ES8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1765ES8#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 LT1765ES8#PBF part is unused and in its original packaging.
Return procedure for LT1765ES8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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