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Analog Devices Inc. LT1576IS8#TRPBF
- Part No.:
- LT1576IS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1576IS8#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,697
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Product details
Overview
LT1576IS8#TRPBF from Analog Devices (formerly Linear Technology) is a 200kHz monolithic step-down switching regulator with integrated 1.5A NPN power switch, 1.21V reference, and fused-lead SO-8 package. It delivers fixed 5V output at up to 1.25A with input voltage range 6V–25V, cycle-by-cycle current limiting, and shutdown current of 20µA. Used in battery-powered systems requiring compact, efficient DC/DC conversion.
For engineers reviewing the LT1576IS8#TRPBF datasheet, LT1576IS8#TRPBF pinout, LT1576IS8#TRPBF application, or LT1576IS8#TRPBF equivalent, key selection criteria include its 5V fixed-output configuration (SENSE pin), 200kHz constant-frequency current-mode control, fused-ground thermal enhancement, BOOST pin for switch saturation, and compatibility with standard surface-mount magnetics and capacitors.
Technical Context
The LT1576IS8#TRPBF implements current-mode control with an internal 200kHz oscillator, error amplifier (1000 µMho transconductance), and peak-current comparator referenced to the SENSE pin. Its architecture includes slope compensation to prevent subharmonic oscillation and frequency foldback below 0.7V SENSE voltage to limit power dissipation during short-circuit conditions.
It uses a bipolar NPN switch with 0.2Ω typical on-resistance, driven via BOOST pin to achieve saturation-reducing conduction loss versus conventional bipolar designs. The fused ground lead in the SO-8 package lowers θJA to 80°C/W when connected to a ground plane, enabling operation up to 125°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5V ±1.2% (4.94V–5.06V), sensed directly at SENSE pin for tight regulation without external divider. |
| Switch Current Limit | 1.5A typical at ≤50% duty cycle; derates nonlinearly to 1.3A at 80% duty cycle due to internal slope compensation. |
| Switching Frequency | 200kHz nominal (180–220kHz); stable over input voltage and load, with synchronizable option (not on this variant). |
| Reference Voltage | 1.21V internal bandgap reference; enables precise output setting and supports adjustable variants via FB pin. |
| Shutdown Current | 20µA max at VSHDN = 0V; enables ultra-low-power standby in portable applications. |
| Thermal Resistance | θJA = 80°C/W with fused ground pin connected to PCB ground plane-critical for sustained 1.25A operation at elevated ambient. |
| Input Voltage Range | 6V to 25V minimum; requires ≥5.5V to maintain regulation under all load/temperature conditions per test guarantee. |
Pinout & Package
LT1576IS8#TRPBF is housed in an 8-lead plastic SOIC (SO-8) package with fused ground lead for enhanced thermal performance. Pin 4 (GND) is internally bonded to a dedicated ground tab to reduce thermal resistance to the PCB.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW (Pin 1) | Switch emitter | Connects to inductor; swings negative during off-time-requires catch diode clamping to −0.8V max. |
| VIN (Pin 2) | Switch collector & bias source | Supplies internal circuitry; high dI/dt node-bypass capacitor must be placed adjacent to minimize ringing. |
| BOOST (Pin 3) | Switch drive boost supply | Driven 5V above VIN via external capacitor/diode; enables NPN saturation and 0.2Ω effective RON. |
| GND (Pin 4) | Power and signal reference | Fused lead reduces θJA; must tie directly to low-impedance ground plane to ensure load regulation and EMI control. |
| BIAS (Pin 5) | Efficiency-optimized bias supply | Accepts regulated output (≥3.3V); shifts internal bias current from VIN to VOUT, improving efficiency at high VIN/light loads. |
| VC (Pin 6) | Error amplifier output / current limit input | Compensation node; also serves as current clamp point-driving it low disables switching. |
| SENSE (Pin 7) | Fixed-output voltage sense | Replaces FB pin on -5 variants; connects directly to 5V output; triggers foldback if voltage drops below 0.7V. |
| SHDN (Pin 8) | Shutdown control | Two-threshold function: 2.42V UVLO disable, 0.37V micropower shutdown; draws only 20µA in shutdown state. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode control | Enables fast transient response and inherent loop stability without external compensation components beyond standard RC network. |
| Fused ground SO-8 package | Reduces thermal resistance by ~30% vs standard SO-8-extends usable ambient temperature range and supports 1.25A continuous output. |
| Frequency foldback | Automatically reduces switching frequency 5:1 when SENSE < 0.7V, limiting power dissipation in IC, diode, and inductor during short-circuit faults. |
| BOOST-driven NPN switch | Achieves 0.2Ω effective on-resistance and >88% efficiency-eliminates need for external MOSFET drivers or high-side FETs. |
| Integrated cycle-by-cycle current limiting | Protects against overload and short-circuit without external sensing resistors; operates down to 8% minimum duty cycle. |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Main 5V rail generation from Li-ion or multi-cell alkaline battery packs in laptops and tablets. IC Role / Device Role / Timing Role: Primary buck converter delivering regulated 5V at up to 1.25A with low quiescent current and thermal robustness. Use Value: Enables extended runtime via 1.16mA effective supply current and 20µA shutdown mode; fused SO-8 withstands thermal cycling in compact chassis. | 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 operating across wide input voltage (6–25V) and temperature ranges. Use Value: Stable regulation with no external feedback resistors; foldback protection prevents thermal runaway during accidental shorts in unattended operation. |
| Battery Charger | Distributed Power |
Use Scenario: Auxiliary 5V supply for charging circuitry (e.g., USB-C PD controllers, charge management ICs) in multi-bay chargers. IC Role / Device Role / Timing Role: Isolated secondary-side buck regulator providing clean 5V bias for communication interfaces and status LEDs. Use Value: Immunity to input ripple from upstream converters; BOOST pin ensures consistent switch saturation even with varying input from AC/DC adapter. | Use Scenario: Local 5V regulation in industrial PLC I/O modules, where centralized 24V DC bus powers multiple distributed nodes. IC Role / Device Role / Timing Role: Point-of-load converter converting 24V bus to 5V for logic, communication, and sensor interfaces. Use Value: High efficiency (>88%) minimizes heat buildup in sealed enclosures; SO-8 fused ground supports conduction cooling in dense board layouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EDE#TRPBF | 4MHz synchronous buck, 3A output, integrated MOSFETs; requires no external diode; 2.5V–5.5V input only. | Not suitable for 6–25V input range; better for space-constrained, low-input-voltage apps needing higher current. | Select LTC3605EDE#TRPBF only if input is ≤5.5V and synchronous efficiency/space savings outweigh input range limitation. |
| TPS54202DRCT | 2.5A synchronous buck, 4.5–28V input, 5V fixed option; 500kHz switching; no BOOST pin or fused ground. | Higher current capability but lacks fused thermal path and BOOST-assisted saturation-less efficient at high VIN/low IOUT. | Choose TPS54202DRCT for higher output current needs where thermal design allows standard SO-8 layout and efficiency trade-offs are acceptable. |
Compared with LTC3605EDE#TRPBF and TPS54202DRCT, the LT1576IS8#TRPBF uniquely combines wide 6–25V input support, fused-ground thermal performance, and BOOST-enabled bipolar saturation-making it optimal for rugged, medium-current, wide-input industrial and portable applications where reliability under fault conditions is critical.
Availability
LT1576IS8#TRPBF is available at Aetrix Electronics and suitable for battery-powered systems, portable computers, and distributed power architectures requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LT1576IS8#TRPBF 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 product support, documentation, and manufacturing continuity for the LT family.
The LT1576 series was designed specifically for noise-sensitive, thermally constrained buck conversion in portable and industrial equipment-emphasizing EMI reduction, thermal robustness, and fault resilience over raw speed or integration density.
FAQ
What is the maximum continuous output current for LT1576IS8#TRPBF at 5V output?
The LT1576IS8#TRPBF delivers up to 1.25A continuous output current at 5V when using a 15µH inductor and 10V input, per the typical application curve. At higher input voltages (e.g., 25V), maximum load current decreases due to increased inductor ripple current-verify against the "Maximum Load Current" graphs in the LT1576 datasheet for your specific VIN/L combination. Derating is required above 85°C ambient.
Does LT1576IS8#TRPBF require an external catch diode, and what type is recommended?
Yes, LT1576IS8#TRPBF requires an external Schottky catch diode (e.g., 1N5818) connected between VSW and GND. The diode must handle peak inductor current (≥1.5A) and reverse voltage ≥VIN. Schottky types are mandatory for low forward drop and fast recovery; standard silicon diodes cause excessive loss and instability due to slow recovery and high VF.
How does the BOOST pin function in LT1576IS8#TRPBF, and what external components are needed?
The BOOST pin in LT1576IS8#TRPBF supplies elevated drive voltage to the internal NPN switch, enabling saturation and minimizing conduction loss. It requires an external capacitor (typically 100pF) and Schottky diode (e.g., 1N5818) connected from VIN to BOOST. During switch on-time, the diode charges the capacitor to VIN + VF, then the capacitor drives the switch base above VIN for full saturation.
Can LT1576IS8#TRPBF operate with input voltage below 6V, and what is the absolute minimum?
No-LT1576IS8#TRPBF is not specified or guaranteed to operate below 6V input. The absolute minimum input voltage is 5.5V (tested and guaranteed), defined as the level where internal bias lines remain regulated. Below 5.5V, reference voltage drift, oscillator instability, and loss of regulation occur. For 3.3V or lower inputs, consider the LT1576-3.3 or other dedicated low-VIN regulators.
What is the purpose of the SENSE pin on LT1576IS8#TRPBF, and how does it differ from the FB pin?
The SENSE pin on LT1576IS8#TRPBF replaces the FB pin found on adjustable variants and connects directly to the 5V output to enable fixed-output regulation without external resistors. Unlike FB, which compares a divided output to 1.21V, SENSE monitors actual output voltage and triggers foldback (frequency/current limit reduction) if voltage drops below 0.7V-providing intrinsic short-circuit protection unique to the -5 variant.
LT1576IS8#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 5V
- Voltage - Input (Max):
- 25V
- Voltage - Output (Min/Fixed):
- 1.21V
- Voltage - Output (Max):
- 23.5V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1576IS8#TRPBF FAQ
1.How can I place an order for LT1576IS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1576IS8#TRPBF 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 LT1576IS8#TRPBF reliable?
The price and inventory of LT1576IS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1576IS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1576IS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1576IS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1576IS8#TRPBF?
LT1576IS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1576IS8#TRPBF 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 LT1576IS8#TRPBF?
For technical support, including LT1576IS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1576IS8#TRPBF requirements.
6.How does Aetrix verify that LT1576IS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1576IS8#TRPBF 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 LT1576IS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1576IS8#TRPBF?
All LT1576IS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1576IS8#TRPBF, 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 LT1576IS8#TRPBF part is unused and in its original packaging.
Return procedure for LT1576IS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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