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Analog Devices Inc. LT1376IS8#PBF
- Part No.:
- LT1376IS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1376IS8#PBF.pdf
- Description:
- IC REG BUCK SEPIC ADJ 1.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,255
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Product details
Overview
LT1376IS8#PBF from Analog Devices (formerly Linear Technology) is a 500kHz, 1.5A monolithic step-down switching regulator in an 8-lead SOIC package, featuring current-mode control, 0.4Ω internal NPN switch, 2.5mA quiescent supply current, and fixed 5V output. It delivers up to 1.25A at 5V from 6V–25V input for battery-powered systems and portable computers.
For engineers reviewing the LT1376IS8#PBF datasheet, LT1376IS8#PBF pinout, LT1376IS8#PBF application, or LT1376IS8#PBF equivalent, key selection criteria include guaranteed 5V ±1.2% output accuracy over temperature, cycle-by-cycle current limiting, shutdown current ≤75µA, and compatibility with standard surface-mount 5µH inductors and solid tantalum output capacitors.
Technical Context
The LT1376IS8#PBF implements constant-frequency current-mode control using an internal 500kHz oscillator and dual feedback loops: one sensing output voltage via the FB/SENSE pin (2.42V reference), and another monitoring switch current on a cycle-by-cycle basis for fast transient response and inherent loop stability. Its bipolar NPN power switch is driven by a BOOST pin circuit enabling saturation and low conduction loss.
Unlike voltage-mode controllers, this architecture avoids subharmonic oscillation through internal slope compensation and provides predictable peak-current limiting that degrades gracefully with duty cycle-1.5A at ≤50% DC, down to 1.35A at 80% DC. The BIAS pin (present only on LT1376 variants) allows efficiency optimization by sourcing bias current from the regulated 5V output when VIN ≥ 7.5V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.2% (guaranteed over –40°C to 125°C junction temp) |
| Switch Current Limit | 1.5A at ≤50% duty cycle; reduces to 1.35A at 80% duty cycle for subharmonic suppression |
| Switch On Resistance | 0.4Ω typical (enables >87% efficiency at 1A, VIN=10V, VOUT=5V) |
| Quiescent Supply Current | 2.5mA typical (measured with BIAS pin connected to 5V output) |
| Shutdown Current | ≤75µA max at TJ = 125°C (enables ultra-low-power standby in battery systems) |
| Switching Frequency | 500kHz ±6% (440–570kHz over full temperature range; enables compact 5µH inductor) |
| Input Voltage Range | 6V to 25V (minimum start-up voltage 5.5V; operation below 7.5V requires design review) |
Pinout & Package
LT1376IS8#PBF is housed in an 8-lead plastic SOIC (S8) package with θJA = 120–150°C/W depending on PCB layout. Thermal performance is enhanced by grounding exposed pad areas under pins 1–4 and 5–8 where possible.
| 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 high efficiency |
| VIN | Input power collector | Supplies internal circuitry and powers NPN switch collector; requires local 100µF solid tantalum bypass |
| VSW | Switch emitter | Connects to inductor; swings negative during off-time-clamped by external catch diode (e.g., 1N5818) |
| BIAS | Efficiency-optimized bias supply | When tied to 5V output, shifts internal bias current from VIN to VOUT-improves efficiency by >10% at VIN=20V |
| VC | Error amplifier output / current limit control | DC voltage (≈1V–2V) sets peak switch current; used for compensation and optional current clamping |
| FB/SENSE | Output voltage sense input | Fixed 5V version uses internal divider; pin connects directly to 5V output for regulation and short-circuit foldback |
| GND | Power and signal reference | Must be short-traced to load ground to avoid load regulation error; carries high di/dt spikes requiring ground plane |
| SHDN | Enable/disable control | Two-threshold logic: 2.38V UVLO disables switching; 0.4V forces micropower shutdown (≤75µA IQ) |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology | Enables stable operation with minimal phase margin requirements and eliminates need for external slope compensation |
| Integrated 1.5A NPN switch | Eliminates external MOSFET and driver; reduces BOM count and layout complexity while maintaining 0.4Ω conduction loss |
| 500kHz fixed-frequency operation | Permits use of small 5µH surface-mount inductors and reduces EMI filtering burden compared to lower-frequency alternatives |
| Short-circuit protection | Automatic frequency foldback (5:1 reduction below 1V FB) and current limit foldback (<1.7V FB) limit power dissipation during faults |
| BIAS pin efficiency enhancement | Reduces total input-referred quiescent current by shifting bias supply from VIN to regulated 5V output at high input voltages |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Powering 5V logic rails and peripherals in laptops and handheld terminals with wide-input battery sources (7–25V). IC Role / Device Role / Timing Role: Primary 5V buck converter delivering up to 1.25A with tight line/load regulation and thermal robustness. Use Value: Enables compact, high-efficiency power conversion without external FET or controller IC-reducing board area and component count. |
Use Scenario: Regulating 5V for microcontrollers, sensors, and RF modules in wireless sensor nodes powered by Li-ion or multi-cell alkaline packs. IC Role / Device Role / Timing Role: Main system regulator with micropower shutdown (≤75µA) to extend battery life during sleep modes. Use Value: Maintains stable 5V output across battery discharge curve while minimizing no-load current drain. |
| Battery Chargers | Distributed Power |
Use Scenario: Generating isolated 5V auxiliary supply for charge management ICs and status LEDs in multi-bay chargers. IC Role / Device Role / Timing Role: Secondary-side 5V regulator accepting unregulated DC from primary-side flyback or forward converters. Use Value: Tolerates input ripple and transient surges common in charger front-end stages while delivering clean 5V output. |
Use Scenario: Local point-of-load regulation in industrial PLCs or telecom equipment where 5V rails feed FPGA I/O banks or interface ICs. IC Role / Device Role / Timing Role: Compact, thermally efficient 5V buck stage replacing discrete solutions in space-constrained modules. Use Value: Delivers 1.25A at >87% efficiency with SOIC footprint-eliminating need for heatsinking or airflow planning. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1376CS8#PBF | Same silicon, commercial temperature grade (0°C to 125°C) vs. industrial (–40°C to 125°C); identical electrical specs | Suitable for non-automotive/non-industrial environments where ambient temperature stays above 0°C | Select LT1376CS8#PBF only if full industrial temp range is not required-offers same performance at lower cost. |
| LT1507IS8#PBF | Functionally identical 5V buck regulator but optimized for 4.5V–12V input; lacks BIAS pin and has higher min. input voltage (4.5V) | Better suited for low-voltage battery systems (e.g., single-cell LiPo + boost) where VIN rarely exceeds 12V | Choose LT1507IS8#PBF when input never exceeds 12V and BIAS pin functionality is unnecessary-offers tighter input range control. |
Compared with LT1376IS8#PBF, LT1376CS8#PBF trades industrial temperature capability for cost savings without electrical compromise, while LT1507IS8#PBF narrows input range to improve low-VIN regulation but removes BIAS-driven efficiency gains-making LT1376IS8#PBF optimal for wide-input, high-efficiency 5V conversion in harsh environments.
Availability
LT1376IS8#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 industrial-grade temperature performance.
Supply support for LT1376IS8#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 its legacy of high-performance analog and power management ICs with rigorous reliability testing and automotive/industrial qualification.
The LT1376IS8#PBF belongs to Linear's monolithic buck regulator product line, designed specifically for compact, high-efficiency DC/DC conversion in space- and power-constrained applications where integrated switches and fixed outputs reduce design risk.
FAQ
What is the guaranteed output voltage tolerance of the LT1376IS8#PBF over temperature?
The LT1376IS8#PBF guarantees a fixed 5.0V output with ±1.2% tolerance across its full industrial operating junction temperature range of –40°C to 125°C. This specification is verified per the Electrical Characteristics table in the official datasheet and reflects worst-case deviation including initial accuracy, line regulation, and temperature drift-not just room-temperature measurement.
Does the LT1376IS8#PBF require an external catch diode, and what type is recommended?
Yes, the LT1376IS8#PBF requires an external Schottky catch diode connected between VSW and GND. The datasheet specifies the 1N5818 as a validated option-rated for 1A average current and 30V PIV-with low forward voltage (≤0.45V at 1A) to minimize conduction loss and maintain high efficiency. Fast recovery is not required due to the device's current-mode architecture.
How does the BIAS pin improve efficiency in the LT1376IS8#PBF, and when should it be used?
The BIAS pin on the LT1376IS8#PBF allows internal bias circuitry to draw current from the regulated 5V output instead of VIN, reducing total input-referred quiescent current. When VIN = 20V and VOUT = 5V at light load (25mA), this improves efficiency by over 10%. It must be connected to the 5V output rail and is only effective when VOUT ≥ 3.3V and VIN significantly exceeds VOUT.
What is the maximum continuous output current the LT1376IS8#PBF can deliver at 5V with a 10µH inductor and 10V input?
At VIN = 10V, VOUT = 5V, and L = 10µH, the LT1376IS8#PBF delivers up to 1.25A continuously in continuous conduction mode. This value is derived from the 1.5A switch current limit (at 50% duty cycle), minus half the peak-to-peak inductor ripple current (≈0.25A), as confirmed in the "Maximum Load Current" section of the datasheet and validated by the TA01 schematic.
Can the LT1376IS8#PBF be synchronized to an external clock, and if not, what is the alternative?
No, the LT1376IS8#PBF does not support external synchronization-the SYNC pin is exclusive to the LT1375 family. For synchronized operation, engineers should select the LT1375IS8#PBF (same package, same temperature grade) which accepts logic-level inputs from 580kHz to 900kHz. The LT1376IS8#PBF maintains strict 500kHz operation with ±6% variation over temperature and line.
LT1376IS8#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, 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:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1376IS8#PBF FAQ
1.How can I place an order for LT1376IS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1376IS8#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 LT1376IS8#PBF reliable?
The price and inventory of LT1376IS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1376IS8#PBF is usually 5 days.
3.What payment methods are accepted for LT1376IS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1376IS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1376IS8#PBF?
LT1376IS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1376IS8#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 LT1376IS8#PBF?
For technical support, including LT1376IS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1376IS8#PBF requirements.
6.How does Aetrix verify that LT1376IS8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1376IS8#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 LT1376IS8#PBF meets industry standards.
7.What is the process for return or replacement of LT1376IS8#PBF?
All LT1376IS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1376IS8#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 LT1376IS8#PBF part is unused and in its original packaging.
Return procedure for LT1376IS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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