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Analog Devices Inc. LT1376IS#PBF
- Part No.:
- LT1376IS#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1376IS#PBF.pdf
- Description:
- IC REG BUCK SEPIC ADJ 1.5A 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,447
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Product details
Overview
LT1376IS#PBF from Analog Devices (formerly Linear Technology) is a 500kHz, 1.5A monolithic step-down switching regulator in SO-8 package with fixed 5V output, current-mode control, and integrated 0.4Ω NPN power switch. It delivers up to 1.25A at 5V from 6V–25V input, features 20µA shutdown current, cycle-by-cycle current limiting, and is optimized for battery-powered systems and portable computers.
For engineers reviewing the LT1376IS#PBF datasheet, LT1376IS#PBF pinout, LT1376IS#PBF application, or LT1376IS#PBF equivalent, key selection criteria include its fixed 5V output configuration, BIAS pin for efficiency optimization at high VIN/light load, BOOST pin requirement for switch saturation, thermal performance in SO-8 package, and compatibility with standard surface-mount inductors down to 5µH.
Technical Context
The LT1376IS#PBF implements constant-frequency current-mode control using an internal 500kHz oscillator and dual feedback loops: one via the error amplifier (VC pin) setting peak switch current, and another via the current-sense amplifier monitoring switch emitter voltage. Its bipolar NPN switch is driven by a BOOST-supplied voltage higher than VIN to achieve low 0.4Ω on-resistance and >87% efficiency.
It integrates undervoltage lockout (2.38V UVLO threshold on SHDN), foldback protection (frequency reduction below 1V FB/SENSE, current limit reduction below 1.7V), and thermal shutdown. The BIAS pin-present only on LT1376 variants-enables bias current sourcing from VOUT instead of VIN, improving efficiency by >10% at VIN = 20V, VOUT = 5V, IOUT = 25mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.2% (guaranteed over temperature and line) |
| Switch Current Limit | 1.5A at ≤50% duty cycle; derates to 1.35A at 80% duty cycle-defines max continuous load current with inductor ripple subtraction |
| Switch On Resistance | 0.4Ω typical (at ISW = 1.5A, VBOOST = VIN + 5V)-enables low conduction loss and high efficiency without external MOSFET |
| Shutdown Current | 20µA typical (VSHDN = 0V, VIN ≤ 25V)-supports ultra-low-power battery hold-up modes |
| Operating Input Range | 6V to 25V (minimum 5.5V guaranteed for regulation)-requires external PNP assist below 6V per applications note |
| Switching Frequency | 500kHz ±10% (440–570kHz over full temperature range)-enables compact 5–10µH inductors and reduces EMI fundamental |
| Efficiency | Up to 90% at 1A, VIN = 10V, VOUT = 5V-achieved via BOOST-driven saturation and BIAS pin optimization |
Pinout & Package
LT1376IS#PBF is housed in an 8-lead plastic SO (S8) package with exposed pad thermal enhancement. Pin 1 is marked with dot; pin numbering follows standard SO-8 convention (counterclockwise from top-left corner).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST | Boost capacitor drive node | Must be connected to external diode+capacitor network to generate ~VIN+5V; enables NPN switch saturation and 0.4Ω RON |
| VIN | Input supply and switch collector | Supplies internal circuitry and powers switch; high di/dt node-requires local 100µF tantalum bypass |
| VSW | Switch emitter output | Drives inductor; swings negative during off-time-requires external catch diode (e.g., 1N5818) clamped to GND |
| BIAS | Internal bias supply source | Connect to VOUT ≥3.3V to reduce input-referred quiescent current; improves efficiency at high VIN/light load |
| VC | Error amplifier output / current limit setpoint | Used for loop compensation (RC network to GND); also accepts external clamp for override or shutdown |
| FB/SENSE | Feedback reference / output sense input | Fixed 5V version: connected directly to regulated output; senses 5.0V ±1.2% and triggers foldback below 1.7V |
| GND | Power and signal reference | Must tie to low-impedance ground plane; critical for load regulation and EMI control due to fast GND current spikes |
| SHDN | Enable/disable control | Logic-compatible input: <0.4V = full shutdown (20µA IQ); >2.38V = UVLO disable; 0.4–2.38V = active operation |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology | Enables fast transient response and inherent cycle-by-cycle current limiting without external sense resistor |
| BOOST-assisted saturation | Reduces switch conduction loss to FET-equivalent level (0.4Ω) while retaining bipolar process advantages |
| BIAS pin efficiency boost | Shifts internal bias current sourcing from VIN to VOUT, cutting total input-referred quiescent current by >10% at VIN = 20V |
| Foldback protection | Automatically reduces switching frequency (5:1) and peak current limit when output shorts-limits IC and diode dissipation |
| UVLO with dual thresholds | 2.38V SHDN threshold prevents startup until input stabilizes; 0.4V threshold ensures deep micropower shutdown |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Powering 5V logic rails and peripherals in laptops, tablets, and handheld instruments with wide-input battery packs (7–24V). IC Role / Device Role / Timing Role: Primary 5V buck converter delivering up to 1.25A with tight regulation and low-noise operation. Use Value: Enables compact design using 5µH inductor and eliminates need for external current-sense or compensation components. |
Use Scenario: Regulating 5V for microcontrollers, sensors, and RF modules in wireless sensor nodes and portable test equipment. IC Role / Device Role / Timing Role: High-efficiency DC/DC converter supporting long battery life via 20µA shutdown and BIAS-pin optimization. Use Value: Delivers >87% efficiency at light loads (25mA) and maintains regulation across full battery discharge curve (6–25V). |
| Battery Chargers | Distributed Power |
Use Scenario: Generating stable 5V bias for charging controller ICs and status LEDs in multi-cell Li-ion charger designs. IC Role / Device Role / Timing Role: Auxiliary 5V supply with precise 5.0V ±1.2% output and robust short-circuit foldback. Use Value: Survives accidental output shorts during connector mating/unmating without latch-up or thermal shutdown. |
Use Scenario: Local point-of-load conversion in industrial PLCs and telecom line cards where 5V rails are distributed from higher-voltage backplanes. IC Role / Device Role / Timing Role: Compact, thermally robust 5V regulator mounted near load to minimize IR drop and noise coupling. Use Value: SO-8 package with fused corner pins achieves θJA = 120°C/W (typ.)-supports 1.25A continuous operation without heatsink. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EDE#PBF | 4MHz synchronous buck, 3A, integrated MOSFETs, no BOOST/Bias pins; requires external compensation | Higher frequency enables smaller inductors/caps but lacks foldback protection and UVLO flexibility | Choose for space-constrained designs needing >1.25A or synchronous efficiency; avoid if BOOST-assisted saturation or 500kHz EMI profile is required |
| TPS54202DRCT | 2A synchronous buck, 500kHz, integrated FETs, no BOOST pin; uses D-CAP2 control, no BIAS pin | Higher current rating but lower efficiency at light loads (<100mA) due to lack of BIAS optimization | Choose for cost-sensitive 2A applications without strict micropower shutdown or high-VIN efficiency requirements |
Compared with LTC3605EDE#PBF and TPS54202DRCT, the LT1376IS#PBF uniquely combines BOOST-driven bipolar saturation for low RON, BIAS-pin efficiency tuning, and analog foldback protection-making it optimal for rugged 1.25A 5V supplies where reliability under fault conditions and light-load efficiency are critical.
Availability
LT1376IS#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 traceable sourcing.
Supply support for LT1376IS#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 LT1376 belongs to Linear's monolithic current-mode buck regulator product line, designed specifically for compact, efficient, and robust DC/DC conversion in portable and industrial systems where thermal performance and fault resilience are essential.
FAQ
What is the maximum continuous output current of the LT1376IS#PBF?
The LT1376IS#PBF delivers up to 1.25A at 5V output when operating from 10V input with a 10µH inductor. Maximum load current depends on input voltage, inductor value, and duty cycle-peaking at 1.25A for VIN = 10V and de-rating to ~1.17A at VIN = 15V due to increased ripple current. The internal 1.5A switch current limit and continuous mode formula define the practical boundary.
Does the LT1376IS#PBF require an external BOOST capacitor and diode?
Yes-the LT1376IS#PBF requires an external BOOST capacitor (typically 10nF–100nF) and Schottky diode (e.g., 1N5818) connected between VIN and BOOST. This network generates a voltage ~5V above VIN to saturate the internal NPN switch, achieving its specified 0.4Ω on-resistance and >87% efficiency. Omitting BOOST results in excessive switch loss and thermal failure.
How does the BIAS pin improve efficiency in the LT1376IS#PBF?
The BIAS pin on the LT1376IS#PBF allows internal bias circuitry to draw operating current from the regulated 5V output instead of the higher input voltage. At VIN = 20V and IOUT = 25mA, this reduces total input-referred quiescent current by >10%, directly extending battery life in high-input-ratio applications without compromising regulation or transient response.
What protection features does the LT1376IS#PBF provide during output short-circuit?
During output short-circuit, the LT1376IS#PBF activates dual foldback protection: switching frequency drops ~5:1 when FB/SENSE voltage falls below 1V, and peak switch current limit reduces when FB/SENSE drops below 1.7V. Combined with thermal shutdown and cycle-by-cycle current limiting, this limits power dissipation in the IC, external diode, and inductor-enabling safe indefinite operation under fault.
Is the LT1376IS#PBF pin-compatible with other members of the LT1375/LT1376 family?
The LT1376IS#PBF shares the same SO-8 pinout as LT1375IS#PBF and LT1376CS#PBF, but differs functionally: LT1375 lacks the BIAS pin, and adjustable versions (e.g., LT1376IS-ADJ#PBF) use FB for external divider instead of SENSE. Always verify BIAS pin connection and FB/SENSE routing-LT1376IS#PBF must connect FB/SENSE directly to VOUT, not a resistor divider.
LT1376IS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-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:
- 16-SO
LT1376IS#PBF FAQ
1.How can I place an order for LT1376IS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1376IS#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 LT1376IS#PBF reliable?
The price and inventory of LT1376IS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1376IS#PBF is usually 5 days.
3.What payment methods are accepted for LT1376IS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1376IS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1376IS#PBF?
LT1376IS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1376IS#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 LT1376IS#PBF?
For technical support, including LT1376IS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1376IS#PBF requirements.
6.How does Aetrix verify that LT1376IS#PBF is sourced from the original manufacturer or authorized distributors?
All LT1376IS#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 LT1376IS#PBF meets industry standards.
7.What is the process for return or replacement of LT1376IS#PBF?
All LT1376IS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1376IS#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 LT1376IS#PBF part is unused and in its original packaging.
Return procedure for LT1376IS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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