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Analog Devices Inc. LT1376IN8#PBF
- Part No.:
- LT1376IN8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1376IN8#PBF.pdf
- Description:
- IC REG BUCK SEPIC ADJ 1.5A 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,152
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Product details
Overview
LT1376IN8#PBF from Analog Devices (formerly Linear Technology) is a 500kHz, 1.5A monolithic step-down switching regulator in 8-pin PDIP package, featuring fixed 5V output, current-mode control, 0.4Ω internal NPN switch, and 20µA shutdown current. It delivers up to 1.25A at 5V from 6V–25V input for battery-powered systems and distributed power rails.
For engineers reviewing the LT1376IN8#PBF datasheet, LT1376IN8#PBF pinout, LT1376IN8#PBF application, or LT1376IN8#PBF equivalent, key selection criteria include guaranteed 5V ±2% output accuracy over temperature, cycle-by-cycle current limiting, BOOST pin voltage headroom requirement, BIAS pin efficiency optimization at high VIN, and thermal derating in PDIP package.
Technical Context
The LT1376IN8#PBF implements constant-frequency current-mode control with an internal 500kHz oscillator, error amplifier (2000 µMho transconductance), and peak-current comparator referenced to the VC pin. Its bipolar NPN power switch uses BOOST pin voltage (≥VIN + 3.5V) to achieve saturation and low on-resistance.
It integrates undervoltage lockout (2.38V SHDN threshold), foldback protection (reduced switching frequency and current limit below 1.7V FB voltage), and thermal shutdown. The fixed 5V version uses internal feedback divider; FB pin functions as SENSE input tied directly to output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±2% (guaranteed over –40°C to 125°C junction temp) |
| Switch Current Limit | 1.5A at ≤50% duty cycle; derates to 1.35A at 80% duty cycle |
| Switch On Resistance | 0.4Ω typical (enables >87% efficiency at 1A, VIN=10V, VOUT=5V) |
| Shutdown Current | 20µA max (ensures ultra-low quiescent drain in battery standby) |
| Switching Frequency | 500kHz ±10% (enables use of 5µH inductor; reduces filter size) |
| Input Voltage Range | 6V to 25V (minimum 5.5V guaranteed start-up; HV variants support 30V) |
| Efficiency | 89% typical at 1A, VIN=10V, VOUT=5V (measured with 10µH inductor) |
Pinout & Package
LT1376IN8#PBF is housed in an 8-lead plastic DIP (N8) package with 0.3" width, θJA = 100°C/W. Pin 1 is top-left corner (notch/indentation side), pin numbering counterclockwise.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: BOOST | Boost capacitor drive node | Must be ≥VIN + 3.5V to saturate internal NPN switch; connects to external diode/capacitor network |
| 2: VIN | Power switch collector & bias supply | Supplies internal circuitry; high di/dt node-requires local 100µF solid tantalum bypass |
| 3: VSW | Switch emitter | Drives inductor; swings negative during off-time-requires catch diode clamping to GND |
| 4: BIAS | Efficiency-optimized bias supply | Connect to regulated 5V output to reduce input current draw; improves efficiency by >10% at VIN=20V |
| 5: VC | Error amplifier output / current limit control | Compensation node; also serves as current clamp input (0.9V–2.1V range); drives peak-current comparator |
| 6: FB/SENSE | Output voltage sense (fixed 5V mode) | Connected directly to 5V output; enables UVLO and foldback protection when voltage drops below 1.7V |
| 7: GND | Power and signal reference | Must tie to load ground point directly; high-frequency spikes require short, low-inductance path to minimize EMI |
| 8: SHDN | Enable/disable control | 0.4V threshold forces micropower shutdown (20µA); 2.38V threshold enables UVLO lockout |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology | Enables fast transient response and stable loop compensation without external type-II/III networks |
| Integrated BOOST drive | Eliminates need for external gate driver; achieves FET-like 0.4Ω RCE(sat) with bipolar process |
| Foldback protection | Reduces switching frequency and current limit during short-circuit-limits IC and diode power dissipation |
| BIAS pin optimization | Redirects internal bias current from VIN to VOUT, cutting total input-referred quiescent current by >30% at VIN=20V |
| Thermal shutdown & cycle-by-cycle limiting | Ensures robust operation under overload, ambient >125°C, or poor PCB heatsinking without external protection |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Main 5V rail generation from Li-ion or multi-cell alkaline battery packs (6V–25V). IC Role / Device Role / Timing Role: Primary buck converter delivering regulated 5V/1.25A to logic, USB peripherals, and display interfaces. Use Value: 20µA shutdown current extends battery life in sleep mode; BOOST-assisted saturation maintains >85% efficiency across full load range. |
Use Scenario: Power management in handheld test equipment, portable medical monitors, and ruggedized data loggers. IC Role / Device Role / Timing Role: High-reliability 5V supply with built-in fault protection and thermal margin for unattended operation. Use Value: Foldback current limiting prevents thermal runaway during accidental short circuits; PDIP package allows manual rework in field-deployed units. |
| Battery Charger Control | Distributed Power Architecture |
Use Scenario: Auxiliary 5V supply for charger IC bias, status LEDs, and microcontroller supervision in multi-bay chargers. IC Role / Device Role / Timing Role: Standby power source that remains active while main charging circuit cycles on/off. Use Value: UVLO (2.38V SHDN threshold) prevents erratic behavior during brown-out; BIAS pin reduces heat generation when input is 12V–24V. |
Use Scenario: Local 5V regulation at point-of-load in industrial PLC backplanes or telecom line cards. IC Role / Device Role / Timing Role: Compact, self-contained DC/DC stage replacing discrete MOSFET+controller solutions. Use Value: 500kHz fixed frequency simplifies EMI filtering; integrated current sensing eliminates external sense resistor and layout sensitivity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1376IS8#PBF | Same electrical specs; 8-lead SOIC package (θJA = 120–150°C/W depending on layout) | Better thermal performance on FR4 with copper pour; not suitable for through-hole assembly | Select for automated SMT production and improved power density; requires re-layout for PDIP footprint. |
| LT1507CS8-5 | Functionally identical 5V buck; supports lower 4.5V min input; no BIAS pin; SO-8 only | Optimized for low-VIN applications (e.g., single-cell LiPo + boost); lacks BIAS efficiency gain at high VIN | Select when input may dip below 6V; avoid if operating above 15V input where LT1376IN8#PBF's BIAS pin yields >10% efficiency gain. |
Compared with LT1376IS8#PBF, the LT1376IN8#PBF offers easier hand-soldering and legacy board compatibility but higher thermal resistance; compared with LT1507CS8-5, it provides superior high-input-voltage efficiency via BIAS pin routing but cannot operate below 6V input.
Availability
LT1376IN8#PBF is available at Aetrix Electronics and suitable for portable computers, battery-powered instrumentation, and distributed power systems requiring stable component supply, long-term obsolescence management, and RoHS-compliant through-hole packaging.
Supply support for LT1376IN8#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 support, datasheet archives, and product longevity commitments for all Linear parts.
The LT1376IN8#PBF belongs to Linear's monolithic current-mode buck regulator family, designed specifically for compact, high-efficiency DC/DC conversion in space-constrained and thermally demanding environments where reliability under fault conditions is critical.
FAQ
What is the minimum input voltage required for LT1376IN8#PBF to start regulation?
The LT1376IN8#PBF guarantees start-up at 5.5V input (typical 5.0V). Below this, internal bias lines may not regulate properly, causing unstable oscillator frequency or reference voltage. For applications requiring <5.5V operation, consider the LT1507CS8-5, which starts at 4.5V. Always verify startup behavior across temperature and load in final design.
Can LT1376IN8#PBF operate without the BOOST capacitor?
No. The LT1376IN8#PBF requires the BOOST capacitor (charged via external diode from VSW) to generate ~VIN + 5V on the BOOST pin. Without it, the internal NPN switch cannot saturate, resulting in excessive VCE drop (>1.5V), severe efficiency loss (<75%), and potential thermal failure at full load. The BOOST network is mandatory per datasheet Figure 1.
How does the BIAS pin improve efficiency in LT1376IN8#PBF?
The BIAS pin on LT1376IN8#PBF routes internal bias current from VIN to the regulated 5V output. At VIN = 20V, this reduces total input-referred quiescent current by >30%, improving light-load efficiency by over 10%. It requires VOUT ≥ 3.3V and direct connection-do not add series resistance or filtering.
What happens when the FB/SENSE pin voltage falls below 1.7V on LT1376IN8#PBF?
Below 1.7V, the LT1376IN8#PBF initiates foldback protection: the current limit reduces progressively, and below 1.0V, switching frequency drops ~5:1. This limits power dissipation in the IC, catch diode, and inductor during short-circuit or severe overload-preventing thermal runaway without external circuitry.
Is LT1376IN8#PBF pin-compatible with LT1375IN8#PBF?
Yes-LT1376IN8#PBF and LT1375IN8#PBF share identical 8-pin PDIP pinout, package dimensions, and absolute maximum ratings. However, LT1375 includes SYNC capability (absent in LT1376) and lacks the BIAS pin. Substitution is electrically safe but forfeits BIAS-driven efficiency gains and adds unused SYNC functionality.
LT1376IN8#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
LT1376IN8#PBF FAQ
1.How can I place an order for LT1376IN8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1376IN8#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 LT1376IN8#PBF reliable?
The price and inventory of LT1376IN8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1376IN8#PBF is usually 5 days.
3.What payment methods are accepted for LT1376IN8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1376IN8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1376IN8#PBF?
LT1376IN8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1376IN8#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 LT1376IN8#PBF?
For technical support, including LT1376IN8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1376IN8#PBF requirements.
6.How does Aetrix verify that LT1376IN8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1376IN8#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 LT1376IN8#PBF meets industry standards.
7.What is the process for return or replacement of LT1376IN8#PBF?
All LT1376IN8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1376IN8#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 LT1376IN8#PBF part is unused and in its original packaging.
Return procedure for LT1376IN8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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