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Analog Devices Inc. LT1375IN8#PBF
- Part No.:
- LT1375IN8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1375IN8#PBF.pdf
- Description:
- IC REG BUCK SEPIC ADJ 1.5A 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,820
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Product details
Overview
LT1375IN8#PBF from Analog Devices (formerly Linear Technology) is a 500kHz monolithic buck switching regulator with integrated 1.5A NPN power switch, fixed 5V output, and current-mode control architecture. It operates from 6V to 25V input, delivers up to 1.25A load current at 5V, features 0.4Ω typical switch on-resistance, 2.5mA quiescent supply current, and 20µA shutdown current. It is used in battery-powered systems requiring compact, efficient DC/DC conversion.
For engineers reviewing the LT1375IN8#PBF datasheet, LT1375IN8#PBF pinout, LT1375IN8#PBF application, or LT1375IN8#PBF equivalent, key selection considerations include its fixed 5V output configuration, 8-pin PDIP package, cycle-by-cycle current limiting, external synchronization capability (LT1375 variant only), and thermal shutdown protection - all critical for portable computing and distributed power designs.
Technical Context
The LT1375IN8#PBF implements constant-frequency current-mode control using an internal 500kHz oscillator and dual feedback loops: one for voltage regulation via the error amplifier driving the VC pin, and another for cycle-by-cycle peak current sensing. Its bipolar NPN switch is driven by a BOOST pin voltage (VIN + 5V), enabling saturation and low conduction loss (0.4Ω).
It features two independent shutdown thresholds: 2.38V for undervoltage lockout (UVLO) and 0.4V for full micropower shutdown. The FB/SENSE pin serves as output voltage sense input (for fixed 5V parts) and enables foldback protection - reducing switching frequency below 1V and lowering current limit below 1.7V during overload or short-circuit conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5V ±1.2% (guaranteed over temperature and line) |
| Switch Current Limit | 1.5A at ≤50% duty cycle; reduces to 1.35A at 80% duty cycle - constrains max continuous load current |
| Switching Frequency | 500kHz nominal (440–570kHz over full temperature range) - enables small external inductors (e.g., 5µH) |
| Input Voltage Range | 6V to 25V (minimum 5.5V guaranteed) - supports 12V rail and wide-input battery systems |
| Quiescent Supply Current | 2.5mA typical (at VIN = 15V) - balances efficiency vs. light-load performance |
| Shutdown Current | 20µA typical (measured at VSHDN = 0V, VIN ≤ 25V) - enables ultra-low-power standby modes |
| Switch On-Resistance | 0.4Ω typical (at ISW = 1.5A, VBOOST = VIN + 5V) - determines conduction loss and thermal rise |
Pinout & Package
LT1375IN8#PBF is housed in an 8-lead plastic DIP (N8) package with through-hole mounting and θJA = 100°C/W thermal resistance. Pin functions are validated per Linear Technology's official LT1375/LT1376 datasheet (13756fd).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST | Boost capacitor drive node | Provides ~VIN + 5V gate drive to saturate internal NPN switch; enables 0.4Ω RON and >87% efficiency |
| VIN | Power switch collector & IC bias source | Supplies internal circuitry and powers switch; high di/dt requires local bypass capacitor placement |
| VSW | Switch emitter node | Connects to inductor; swings negative during off-time - requires external catch diode clamping |
| BIAS | Not connected (NC) on LT1375 | Unused pin; LT1375 lacks BIAS functionality (present only on LT1376) |
| VC | Error amplifier output / current limit comparator input | Controls peak switch current; 1V–2V swing reflects load demand; used for compensation and override |
| FB/SENSE | Output voltage sense input (fixed 5V mode) | Connected directly to 5V output; triggers foldback protection if voltage drops below 1.7V or 1.0V |
| GND | Power and signal reference | Must be tied to load ground point to avoid load regulation error; sensitive to EMI from VSW-GND capacitance |
| SHDN | Logic-level shutdown control | 0.4V threshold enables full micropower shutdown; 2.38V threshold provides accurate UVLO |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology | Enables fast transient response and stable loop compensation without external Type-II/III networks |
| Integrated 1.5A NPN switch | Eliminates external MOSFET and driver; reduces BOM count and layout complexity in space-constrained designs |
| BOOST-driven saturation | Achieves FET-like conduction loss (0.4Ω) with smaller die area than comparable MOSFET-based regulators |
| Cycle-by-cycle current limiting | Prevents switch destruction during output shorts or startup into heavy capacitive loads |
| Two-threshold shutdown | Separates UVLO (2.38V) from deep-sleep mode (0.4V), enabling staged power management in battery systems |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Powering 5V logic rails (USB peripherals, I/O controllers) in laptops and tablets with 12V or multi-cell Li-ion inputs. IC Role / Device Role / Timing Role: Primary step-down regulator delivering regulated 5V from variable battery voltage (6–25V). Use Value: 500kHz switching allows use of 5µH inductors and compact 100µF tantalum output caps - minimizing board area while maintaining >85% efficiency at 1A. |
Use Scenario: Providing stable 5V supply for microcontrollers, sensors, and RF modules in handheld test equipment and wireless sensors. IC Role / Device Role / Timing Role: Main DC/DC converter enabling long battery life via 20µA shutdown current and 2.5mA quiescent draw. Use Value: Dual-threshold SHDN pin permits graceful brownout recovery (UVLO at 2.38V) and zero-power storage mode (0.4V shutdown), extending shelf life. |
| Battery Charger Auxiliary Supply | Distributed Power Architectures |
Use Scenario: Generating isolated 5V bias for charger controller ICs and status LEDs in multi-bay Li-ion chargers. IC Role / Device Role / Timing Role: Local point-of-load regulator fed from intermediate 12V bus, independent of main charging path. Use Value: Fixed 5V output eliminates external feedback resistors; cycle-by-cycle current limiting protects against fault currents during cell insertion/removal. |
Use Scenario: Powering 5V subsystems (communication interfaces, monitoring circuits) in industrial PLCs and telecom line cards with centralized 24V/48V backplanes. IC Role / Device Role / Timing Role: Distributed buck converter providing localized regulation with minimal noise coupling to sensitive analog sections. Use Value: Current-mode control ensures stable operation despite input ripple from shared bus; thermal shutdown prevents failure under sustained overload. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EDE#TRPBF | 4MHz synchronous buck, 3A, 2.5–5.5V input, 16-pin QFN; no BOOST pin required | Higher frequency enables <1µH inductors; unsuitable for >6V input; requires different layout and compensation | Select when input is ≤5.5V and ultra-small solution size is prioritized over wide-input flexibility |
| LM2678SD-5.0/NOPB | 63kHz nonsynchronous buck, 5A, 8–40V input, SO-8; uses external N-channel MOSFET | Lower frequency demands larger magnetics; higher peak current rating but lower efficiency at light loads (70–80%) | Select when higher output current (>1.25A) and wider input range (up to 40V) outweigh efficiency and footprint requirements |
Compared with LTC3605EDE#TRPBF and LM2678SD-5.0/NOPB, the LT1375IN8#PBF uniquely balances wide 6–25V input support, fixed 5V output simplicity, and 500kHz operation in a legacy-compatible PDIP package - making it optimal for cost-sensitive, medium-power industrial and portable designs where board real estate is constrained but not extreme.
Availability
LT1375IN8#PBF is available at Aetrix Electronics and suitable for portable computers, battery-powered systems, and distributed power architectures requiring stable component supply, long-lifecycle support, and RoHS-compliant through-hole assembly.
Supply support for LT1375IN8#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 technical and manufacturing continuity for the LT product family, known for high-performance analog and power management ICs.
The LT1375 belongs to Linear's monolithic current-mode buck regulator product line, designed specifically for compact, efficient DC/DC conversion in portable and battery-operated equipment where reliability, thermal robustness, and ease of design-in are critical.
FAQ
What is the maximum continuous output current of the LT1375IN8#PBF?
The LT1375IN8#PBF delivers up to 1.25A continuous output current at 5V when operating with VIN = 10V and L = 10µH, as specified in the Typical Application schematic (TA01). Maximum current decreases at higher input voltages due to reduced duty cycle and increased inductor ripple; at VIN = 15V, max load is ~1.17A. Peak switch current remains limited to 1.5A (≤50% duty cycle) per electrical characteristics.
Does the LT1375IN8#PBF support external synchronization?
Yes, the LT1375IN8#PBF supports external synchronization via its SYNC pin (Pin 5 in SO-8, not present in N8 PDIP). The SYNC pin accepts logic-level signals from 580kHz to 900kHz with 10–90% duty cycle. This feature is exclusive to the LT1375 family; the LT1376 does not include SYNC functionality. For LT1375IN8#PBF in PDIP, synchronization is not available - only the SO-8 variants (e.g., LT1375IS8#PBF) provide this pin.
What is the purpose of the BOOST pin on the LT1375IN8#PBF?
The BOOST pin on the LT1375IN8#PBF connects to an external boost capacitor and diode to generate a voltage ~5V above VIN, which drives the base of the internal NPN power switch. This ensures full saturation, reducing effective on-resistance to 0.4Ω and improving efficiency to >87%. Without BOOST, conduction loss would increase significantly, degrading thermal performance and efficiency - especially at higher output currents.
How does the LT1375IN8#PBF handle short-circuit conditions?
The LT1375IN8#PBF employs dual-foldback protection: when FB/SENSE voltage drops below 1.7V, the current limit is reduced; below 1.0V, switching frequency folds back ~5:1 (to ~100kHz). This limits power dissipation in the IC, external diode, and inductor during sustained shorts. Combined with cycle-by-cycle current limiting and thermal shutdown, this enables safe operation under continuous fault conditions without device damage.
Is the LT1375IN8#PBF pin-compatible with other members of the LT1375/LT1376 family?
The LT1375IN8#PBF shares identical pinout and package (8-pin PDIP) with LT1375CN8, LT1375IN8-5, LT1376CN8, and LT1376IN8. However, functional differences exist: LT1375 variants include SYNC capability (not on LT1376), and LT1376 variants include BIAS pin functionality (not on LT1375). The LT1375IN8#PBF is fixed 5V output; adjustable versions (e.g., LT1375IN8) require external feedback resistors and different FB pin usage.
LT1375IN8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 5V
- Voltage - Input (Max):
- 25V
- Voltage - Output (Min/Fixed):
- 2.42V
- Voltage - Output (Max):
- 21.5V
- Current - Output:
- 1.5A (Switch)
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LT1375IN8#PBF FAQ
1.How can I place an order for LT1375IN8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1375IN8#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 LT1375IN8#PBF reliable?
The price and inventory of LT1375IN8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1375IN8#PBF is usually 5 days.
3.What payment methods are accepted for LT1375IN8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1375IN8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1375IN8#PBF?
LT1375IN8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1375IN8#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 LT1375IN8#PBF?
For technical support, including LT1375IN8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1375IN8#PBF requirements.
6.How does Aetrix verify that LT1375IN8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1375IN8#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 LT1375IN8#PBF meets industry standards.
7.What is the process for return or replacement of LT1375IN8#PBF?
All LT1375IN8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1375IN8#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 LT1375IN8#PBF part is unused and in its original packaging.
Return procedure for LT1375IN8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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