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Analog Devices Inc. LT1374IS8#PBF
- Part No.:
- LT1374IS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1374IS8#PBF.pdf
- Description:
- IC REG BUCK SEPIC ADJ 4.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:250
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Product details
Overview
LT1374IS8#PBF from Analog Devices (formerly Linear Technology) is a 500kHz monolithic buck switching regulator with integrated 4.5A NPN power switch, current-mode control, and fixed 5V output. It operates from 6V to 25V input, delivers up to 4.25A at 5V, and features cycle-by-cycle current limiting, 20µA shutdown current, and thermal shutdown. Used in battery-powered systems requiring compact, efficient DC/DC conversion.
For engineers reviewing the LT1374IS8#PBF datasheet, LT1374IS8#PBF pinout, LT1374IS8#PBF application, or LT1374IS8#PBF equivalent, key selection factors include its fixed 5V output configuration (SENSE pin), SO-8 package with fused ground pin, 0.07Ω switch on-resistance, 500kHz constant-frequency operation, and support for external synchronization or shutdown via shared SYNC/SHDN pin.
Technical Context
The LT1374IS8#PBF implements current-mode control using an internal error amplifier (2000 µMho transconductance), peak-current sensing, and slope compensation to prevent subharmonic oscillation. Its bipolar NPN switch is driven by a BOOST pin voltage ≥ VIN + 5V, enabling saturation and low conduction loss.
It integrates oscillator, logic, and protection circuitry-including undervoltage lockout (2.38V threshold), thermal shutdown, and dual shutdown thresholds (0.4V full shutdown, 2.38V UVLO). The SENSE pin (replacing FB in -5 variants) monitors regulated 5V output directly, eliminating external feedback resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.2% (SENSE pin referenced; no external divider required) |
| Switch Current Limit | 4.5A typical (derates nonlinearly above 50% duty cycle; e.g., 4.3A at 62.5% DC) |
| Switch On Resistance | 0.07Ω typical (enables high efficiency >89% at 5V/2A with proper BOOST capacitor) |
| Switching Frequency | 500kHz ±8% (constant frequency; synchronizable from 580kHz to 1MHz) |
| Shutdown Current | 20µA max (at VIN ≤25V; enables ultra-low-power standby in portable systems) |
| Input Voltage Range | 6V to 25V (minimum start-up voltage ~5.5V; supports 12V rail and wide-input battery systems) |
| Operating Temp Range | –40°C to +125°C (industrial-grade junction temperature rating) |
Pinout & Package
LT1374IS8#PBF is housed in an 8-lead plastic SOIC (SO-8) package with fused ground pin (FGND) for enhanced thermal performance (θJA = 80°C/W with FGND connected to ground plane). The exposed fused ground pad improves power dissipation and EMI control.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply and switch collector | Accepts 6–25V; powers internal circuitry; requires low-inductance bypassing near pin |
| BOOST | Switch driver boost supply | Must be ≥VIN + 5V (min 2.3V above VIN); drives NPN switch into saturation via external capacitor/diode |
| FGND | Fused ground reference | Primary GND return; must be soldered to large copper area for thermal/EMI performance |
| VSW | Switch emitter output | Drives external inductor; swings negative during off-time (clamped by catch diode to –0.8V max) |
| VC | Error amplifier output / current limit control | Used for loop compensation; also serves as current clamp point (0.9V threshold, 2.1V clamp) |
| BIAS | Internal bias supply input | Connect to VOUT ≥3.3V to improve efficiency at high VIN/light load (not used in all designs) |
| SYNC/SHDN | Multi-function logic input | Logic-high (>1.5V): enables sync mode; logic-low (<0.6V): initiates shutdown (20µA IQ) |
| SENSE | Fixed-output voltage sense input | Direct connection to 5V output; replaces FB pin; sets regulation point at 5.0V ±1.2% |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology | Enables fast transient response and inherent stability without complex compensation networks |
| Integrated 4.5A NPN switch | Eliminates external MOSFET; reduces BOM count and layout complexity in space-constrained designs |
| BOOST-driven saturation | Reduces switch VCE(sat) to ~0.3V (vs. ~1.5V in conventional bipolar designs), improving efficiency by >14% |
| Frequency foldback & current limit foldback | Automatically reduces switching frequency and peak current during short-circuit or low-VOUT conditions to limit power dissipation |
| Dual shutdown thresholds | 2.38V UVLO prevents startup until input is stable; 0.4V full shutdown reduces IQ to 20µA for battery longevity |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Main 5V rail generation from Li-ion or multi-cell battery packs (8–24V). IC Role / Device Role / Timing Role: Primary step-down regulator delivering up to 4.25A at 5V with tight load regulation and thermal robustness. Use Value: Enables compact, high-efficiency power stage without external FET or complex compensation-critical for thin-profile notebooks and tablets. |
Use Scenario: Power management in handheld test equipment, medical monitors, and ruggedized field instruments. IC Role / Device Role / Timing Role: Fixed 5V supply for microcontrollers, sensors, and analog front-ends under variable battery voltage and temperature. Use Value: Industrial temp range (–40°C to +125°C) and cycle-by-cycle current limiting ensure reliable operation during cold starts and fault conditions. |
| Battery Chargers | Distributed Power |
Use Scenario: Auxiliary 5V supply for charger control ICs and status LEDs in multi-bay smart chargers. IC Role / Device Role / Timing Role: Isolated 5V rail generator supporting USB-compliant charging logic and communication interfaces. Use Value: Shutdown current of 20µA minimizes quiescent drain on standby batteries; SYNC capability allows noise-sensitive timing alignment with system clock. |
Use Scenario: Local 5V regulation at point-of-load in telecom line cards, industrial PLC modules, and distributed sensor nodes. IC Role / Device Role / Timing Role: Compact, self-contained buck converter replacing discrete switcher solutions in space-limited slots. Use Value: SO-8 package with fused ground simplifies thermal design; 500kHz operation allows small 5–10µH inductors and <100µF output capacitance. |
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 | 4A synchronous buck, 3MHz switching, integrated MOSFETs, 2.7–5.5V input | Lower input voltage range; higher frequency enables smaller passives but less suitable for 12–24V inputs | Prefer for ultra-compact, low-input designs where size outweighs input voltage range |
| TPS54331DR | 3A adjustable-output buck, 570kHz, external MOSFETs, 3.5–28V input | No fixed 5V option; requires external feedback resistors; lacks integrated BOOST drive | Choose when adjustable output or higher input voltage margin (up to 28V) is required |
Compared with LT1374IS8#PBF, LTC3605EDE#PBF offers higher integration and frequency but narrower input range, while TPS54331DR provides greater input flexibility and adjustability at the cost of external FETs and no BOOST-assisted saturation.
Availability
LT1374IS8#PBF is available at Aetrix Electronics and suitable for portable computers, battery-powered systems, and distributed power applications requiring stable component supply, industrial temperature operation, and fixed 5V output with minimal external components.
Supply support for LT1374IS8#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. Linear's buck regulators emphasize robustness, simplicity, and wide operating ranges.
The LT1374IS8#PBF belongs to Linear's monolithic current-mode buck regulator family, designed specifically for industrial and portable applications demanding high current, fixed-output simplicity, and reliable fault protection without external complexity.
FAQ
What is the function of the SENSE pin on the LT1374IS8#PBF?
The SENSE pin on the LT1374IS8#PBF replaces the FB (feedback) pin found on adjustable versions and is internally connected to a precision 5.0V reference. It must be tied directly to the regulated 5V output to close the control loop-no external resistor divider is needed. This pin also enables foldback protection: if SENSE voltage drops below 1.7V, peak switch current is reduced; below 1.0V, switching frequency folds back to limit power dissipation during faults. The LT1374IS8#PBF relies on this pin for both regulation and fault resilience.
Can the LT1374IS8#PBF be synchronized to an external clock?
Yes, the LT1374IS8#PBF supports external synchronization via its multipurpose SYNC/SHDN pin. When driven with a logic-level signal (10–90% duty cycle) between 580kHz and 1MHz, the internal oscillator locks to that frequency-eliminating beat frequencies in multi-regulator systems. To enable sync mode, apply ≥1.5V to the SYNC/SHDN pin; applying <0.6V instead initiates shutdown. The LT1374IS8#PBF does not require additional components for sync, making it suitable for noise-sensitive applications like data acquisition or RF subsystems.
What is the minimum input voltage required for the LT1374IS8#PBF to start regulation?
The LT1374IS8#PBF has a guaranteed minimum start-up input voltage of 5.5V (typical 5.0V), defined as the point where internal bias lines stabilize and regulation begins. However, sustained operation at full 4.25A output requires sufficient headroom: for VOUT = 5V, VIN must exceed ~6V to maintain >50% duty cycle and avoid current derating. At VIN = 6V, maximum load current drops to ~3.5A due to duty cycle constraints and switch current limit reduction. The LT1374IS8#PBF is therefore optimized for 8–25V inputs, not ultra-low-voltage battery start-up.
How does the BOOST pin improve efficiency in the LT1374IS8#PBF?
The BOOST pin on the LT1374IS8#PBF supplies a voltage ≥VIN + 5V to the base drive of the internal NPN power switch, forcing deep saturation and reducing VCE(sat) to ~0.3V (vs. ~1.5V in standard bipolar designs). This is achieved using an external bootstrap capacitor and diode charged during switch-off time. As a result, conduction losses drop significantly-enabling >89% efficiency at 5V/2A-and eliminates need for external MOSFETs. The LT1374IS8#PBF's BOOST architecture is essential to achieving its 0.07Ω effective switch resistance and high power density.
Does the LT1374IS8#PBF require a heatsink in SO-8 package?
The LT1374IS8#PBF in SO-8 package does not require an external heatsink under typical operating conditions (≤3A load, 25°C ambient), provided the fused ground (FGND) pin is soldered to ≥1 cm² of 2-oz copper on the PCB. Thermal resistance is θJA = 80°C/W with FGND connected to ground plane; junction temperature remains below 125°C at 4.25A only with adequate copper area and airflow. For continuous 4A+ loads in enclosed environments, adding thermal vias under the FGND pad and using inner-layer copper planes is strongly recommended. The LT1374IS8#PBF's thermal design relies on PCB layout-not external hardware.
LT1374IS8#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:
- 4.5A (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
LT1374IS8#PBF FAQ
1.How can I place an order for LT1374IS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1374IS8#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 LT1374IS8#PBF reliable?
The price and inventory of LT1374IS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1374IS8#PBF is usually 5 days.
3.What payment methods are accepted for LT1374IS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1374IS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1374IS8#PBF?
LT1374IS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1374IS8#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 LT1374IS8#PBF?
For technical support, including LT1374IS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1374IS8#PBF requirements.
6.How does Aetrix verify that LT1374IS8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1374IS8#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 LT1374IS8#PBF meets industry standards.
7.What is the process for return or replacement of LT1374IS8#PBF?
All LT1374IS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1374IS8#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 LT1374IS8#PBF part is unused and in its original packaging.
Return procedure for LT1374IS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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