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Analog Devices Inc. LT1374IR#PBF
- Part No.:
- LT1374IR#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LT1374IR#PBF.pdf
- Description:
- IC REG BUCK SEPIC ADJ 4.5A DDPAK
- Quantity:
- Payment:
- Shipping:
Inventory:109
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Product details
Overview
LT1374IR#PBF from Analog Devices (formerly Linear Technology) is a 500kHz monolithic buck switching regulator with an integrated 4.5A NPN power switch, current-mode control architecture, and fixed 5V output voltage. It operates from 6V to 25V input, delivers up to 4.25A continuous output, and features cycle-by-cycle current limiting, thermal shutdown, and 20µA shutdown current. It is used in battery-powered systems requiring compact, high-efficiency DC/DC conversion.
For engineers reviewing the LT1374IR#PBF datasheet, LT1374IR#PBF pinout, LT1374IR#PBF application, or LT1374IR#PBF equivalent, key selection considerations include its 5V fixed output configuration, 16-pin TSSOP exposed-pad package, 0.07Ω switch on-resistance, 500kHz constant-frequency operation, and support for external synchronization up to 1MHz.
Technical Context
The LT1374IR#PBF implements current-mode control using an internal error amplifier (2000 µMho transconductance), peak-current sensing, and slope compensation to ensure stability across wide duty cycles. Its bipolar NPN switch is driven via a BOOST pin that enables saturation-reducing conduction loss to ~0.07Ω at 4.5A and enabling >89% efficiency at 5V/4A output.
It integrates dual shutdown thresholds: 2.38V for undervoltage lockout (UVLO) and 0.4V for full micropower shutdown. The SENSE pin (replacing FB in -5 variants) monitors regulated 5V output directly, while SYNC replaces SHDN in synchronized versions-both functions confirmed for the IR-grade temperature range (–40°C to 125°C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.2% (4.94V–5.06V), referenced to internal 5V SENSE threshold |
| Switch Current Limit | 4.5A typical at ≤50% duty cycle; derates nonlinearly to 3.7A at 80% duty cycle due to slope compensation |
| Switching Frequency | 500kHz nominal (460–540kHz over temp); synchronizable from 580kHz to 1MHz via SYNC pin |
| Supply Current | 2.5mA typical operating current; drops to 20µA in shutdown mode |
| Switch On Resistance | 0.07Ω typical at ISW = 4.5A, achieved via BOOST-driven saturation of internal NPN switch |
| Input Voltage Range | 6V to 25V (minimum start-up VIN = 5.5V; minimum running VIN depends on VOUT and load) |
| Operating Temp Range | –40°C to +125°C junction (I-grade), validated for industrial and embedded power applications |
Pinout & Package
LT1374IR#PBF is packaged in a 16-lead plastic TSSOP with exposed pad (FE16), optimized for thermal dissipation (θJA = 40°C/W with exposed pad soldered to ground plane). Both VIN pins (pins 3 & 4) and both VSW pins (pins 10 & 11) must be shorted externally on PCB.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (pins 1, 8, 9, 16) | Power and signal reference ground | Multiple GND pins reduce ground impedance; critical for load regulation and EMI control-must connect to low-inductance ground plane |
| VIN (pins 3, 4) | Input supply and switch collector | Supplies internal circuitry and powers NPN switch; requires local 100µF tantalum + 0.27µF ceramic bypass close to pins |
| BOOST (pin 5) | Switch driver boost voltage node | Connected to external capacitor-diode network to generate ~VIN+5V drive; enables 0.07Ω switch RON |
| SENSE (pin 6) | 5V output voltage feedback input | Direct connection to 5V output; replaces FB pin in fixed-output variants; triggers foldback below 1.7V |
| SYNC (pin 12) | External oscillator synchronization input | Logic-compatible (10–90% duty cycle); overrides internal 500kHz oscillator; replaces SHDN in -SYNC variants |
| SHDN (pin 13) | Shutdown control input | 0.4V threshold for full shutdown (20µA IQ); 2.38V threshold for UVLO; not present on -SYNC variants |
| VC (pin 14) | Error amplifier output / current limit setpoint | Used for loop compensation; also serves as current clamp node (0.9V switching threshold, 2.1V clamp) |
| BIAS (pin 15) | Efficiency-boosting bias supply input | Accepts external 3–7V source (e.g., regulated output); reduces VIN supply current and improves light-load efficiency |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology with slope compensation | Enables stable operation up to 93% duty cycle and fast transient response without external compensation |
| Integrated 4.5A NPN power switch | Eliminates external MOSFET; achieves 0.07Ω effective RON via BOOST-driven saturation |
| Two-stage shutdown logic | 2.38V UVLO prevents startup until input is valid; 0.4V deep-shutdown reduces IQ to 20µA |
| Feedback foldback protection | Reduces switching frequency and current limit when SENSE voltage falls below 1.7V or 1.0V-limits power dissipation during short-circuit |
| Exposed-pad TSSOP thermal design | θJA = 40°C/W with exposed pad soldered to ground plane-supports 4.25A continuous output without heatsink |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Core voltage regulation for embedded controllers and peripherals in ultra-thin laptops. IC Role / Device Role / Timing Role: Fixed 5V buck converter supplying I/O rails and USB interface circuitry. Use Value: 500kHz switching enables use of small 5µH inductors and low-profile capacitors-reducing board area by >35% vs. 100kHz alternatives. |
Use Scenario: Power management in handheld test equipment with Li-ion battery input (8–16V). IC Role / Device Role / Timing Role: Primary 5V system rail generator with shutdown control for sleep/wake cycles. Use Value: 20µA shutdown current extends battery life; thermal shutdown protects against enclosure overheating during extended operation. |
| Battery Chargers | Distributed Power |
Use Scenario: Auxiliary 5V supply for charger controller ICs and status LEDs in multi-cell Li-ion chargers. IC Role / Device Role / Timing Role: Isolated 5V rail derived from main charging bus (12–24V). Use Value: Cycle-by-cycle current limiting prevents damage during charger fault conditions; SENSE pin simplifies feedback layout. |
Use Scenario: Local 5V regulation for remote sensor nodes powered via 24V PoE-derived bus. IC Role / Device Role / Timing Role: Point-of-load (POL) buck converter delivering 4.25A to FPGA I/O banks and ADCs. Use Value: Synchronization capability allows alignment with master clock domain-reducing conducted EMI in dense PCB layouts. |
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; no BOOST pin required | Higher frequency enables smaller magnetics but lower max current; lacks foldback protection | Prefer for space-constrained designs needing <4A; avoid where short-circuit robustness is critical |
| TPS54331DR | 3A adjustable-output buck, 570kHz, external compensation; no BIAS or SYNC pins | Lower cost and simpler layout, but no thermal foldback, no exposed-pad package, and no UVLO hysteresis | Prefer for cost-sensitive industrial supplies with stable input; avoid for battery inputs with wide VIN swing |
Compared with LT1374IR#PBF, LTC3605EDE#PBF offers higher integration and frequency but sacrifices short-circuit resilience and thermal margin, while TPS54331DR trades protection features and package thermal performance for lower BOM cost and design simplicity.
Availability
LT1374IR#PBF is available at Aetrix Electronics and suitable for portable computers, battery-powered systems, and distributed power applications requiring stable component supply, industrial temperature grade (-40°C to +125°C), and long-term availability in surface-mount packaging.
Supply support for LT1374IR#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, including precision analog, power management, and signal conditioning ICs.
The LT1374IR#PBF belongs to Linear's monolithic current-mode buck regulator product line, designed specifically for high-efficiency, high-current DC/DC conversion in space- and thermal-constrained industrial and portable systems.
FAQ
What is the maximum continuous output current of the LT1374IR#PBF?
The LT1374IR#PBF delivers up to 4.25A continuous output at 5V when configured with appropriate external components (e.g., 5µH inductor, 100µF input cap, MBRS330T3 catch diode) and proper PCB thermal layout. Peak switch current is rated at 4.5A ≤50% duty cycle, but maximum load current decreases with increasing VIN due to ripple current effects-verified per Figure 15 in the LT1374 datasheet.
Does the LT1374IR#PBF require an external BOOST capacitor and diode?
Yes, the LT1374IR#PBF requires an external BOOST capacitor (typically 10nF–100nF ceramic) and Schottky diode (e.g., CMDSH3) connected between VIN and BOOST pins. This network generates the boosted gate drive voltage needed to saturate the internal NPN switch and achieve its specified 0.07Ω on-resistance-omitting it degrades efficiency and increases thermal stress on the LT1374IR#PBF.
How does the SENSE pin function differ from the FB pin in other LT1374 variants?
In the LT1374IR#PBF (fixed 5V version), the SENSE pin replaces the FB pin and connects directly to the regulated 5V output. It performs three roles: (1) closed-loop voltage regulation via internal 5V reference, (2) initiation of current foldback below 1.7V, and (3) disabling of synchronization below 1.5V. Unlike adjustable variants, no external resistor divider is needed-simplifying layout and improving accuracy.
Can the LT1374IR#PBF be synchronized to an external clock?
Yes-the LT1374IR#PBF supports external synchronization via its SYNC pin (pin 12), accepting logic-level signals (10–90% duty cycle) from 580kHz to 1MHz. This feature allows noise reduction through clock alignment in multi-regulator systems. Note: the standard LT1374IR#PBF includes SHDN on pin 13; for SYNC functionality, the -SYNC variant (e.g., LT1374IR-SYNC) must be selected.
What thermal considerations apply to the LT1374IR#PBF in the 16-pin TSSOP package?
The LT1374IR#PBF in FE16 package requires the exposed pad to be soldered to a minimum 0.5 square inch copper area connected to GND for θJA = 40°C/W. Without this, junction temperature rise exceeds safe limits at >2.5A. Thermal shutdown activates at TJ = 125°C, and the device derates current above 85°C ambient-validated per the "Maximum Load Current" curves in the LT1374 datasheet.
LT1374IR#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- 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:
- DDPAK-7
LT1374IR#PBF FAQ
1.How can I place an order for LT1374IR#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1374IR#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 LT1374IR#PBF reliable?
The price and inventory of LT1374IR#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1374IR#PBF is usually 5 days.
3.What payment methods are accepted for LT1374IR#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1374IR#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1374IR#PBF?
LT1374IR#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1374IR#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 LT1374IR#PBF?
For technical support, including LT1374IR#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1374IR#PBF requirements.
6.How does Aetrix verify that LT1374IR#PBF is sourced from the original manufacturer or authorized distributors?
All LT1374IR#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 LT1374IR#PBF meets industry standards.
7.What is the process for return or replacement of LT1374IR#PBF?
All LT1374IR#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1374IR#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 LT1374IR#PBF part is unused and in its original packaging.
Return procedure for LT1374IR#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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