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Analog Devices Inc. LT1576CS8#PBF
- Part No.:
- LT1576CS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1576CS8#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:108
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Product details
Overview
LT1576CS8#PBF 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 up to 1.25A at fixed 5V output (via SENSE pin), supports 6V–25V input, and features cycle-by-cycle current limiting and thermal-enhanced ground pin for extended ambient operation in portable computers and battery-powered systems.
For engineers reviewing the LT1576CS8#PBF datasheet, LT1576CS8#PBF pinout, LT1576CS8#PBF application, or LT1576CS8#PBF equivalent, key selection criteria include its 0.2Ω switch on-resistance, 20µA shutdown current, 180–220kHz switching frequency range, feedback voltage tolerance of ±1.2%, and compatibility with standard surface-mount inductors down to 15µH.
Technical Context
The LT1576CS8#PBF implements current-mode control with internal slope compensation to prevent subharmonic oscillation across 50–90% duty cycles. Its dual-threshold shutdown pin provides undervoltage lockout at 2.42V and full micropower shutdown at 0.37V, while the BOOST pin enables saturation of the internal NPN switch via external capacitor/diode, reducing conduction loss versus conventional bipolar designs.
It integrates a 1.21V bandgap reference, error amplifier with 1000µMho transconductance, and VC pin that serves as both error amplifier output and peak-current comparator input. The fused SO-8 package thermally couples GND to PCB plane, achieving θJA = 80°C/W - critical for sustained 1.25A operation without forced airflow.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Limit | 1.5A typical; sets maximum deliverable load current before foldback activation under short-circuit conditions |
| Switch On Resistance | 0.2Ω typical at 1.5A; reduces conduction loss and improves efficiency vs. standard bipolar regulators |
| Feedback Voltage | 1.21V ±1.2%; precise reference enabling accurate 5V output regulation with internal SENSE resistor network |
| Shutdown Current | 20µA max; enables ultra-low-power standby in battery-backed systems |
| Switching Frequency | 200kHz ±10%; balances efficiency, EMI, and inductor size - allows use of compact 15µH surface-mount inductors |
| Input Voltage Range | 6V to 25V; supports wide-range industrial and automotive battery inputs without external pre-regulation |
| Thermal Resistance | θJA = 80°C/W with fused GND pin connected to PCB ground plane; extends continuous 1.25A operation to +85°C ambient |
Pinout & Package
Fused-lead 8-pin plastic SOIC (SO-8) package with exposed thermal pad tied to GND; pin 4 (GND) is fused to reduce thermal resistance and improve power dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW (Pin 1) | Switch emitter | Drives inductor; clamped negative swing requires external catch diode; high dI/dt node demanding short PCB trace |
| VIN (Pin 2) | Switch collector & bias source | Supplies internal circuitry when BIAS pin is open; high-voltage, high-current path requiring local 100µF tantalum bypass |
| BOOST (Pin 3) | Bootstrap drive voltage | Enables NPN saturation via external capacitor/diode; reduces VCE(sat) to ~0.2Ω-equivalent loss |
| GND (Pin 4) | Power & signal reference | Fused lead minimizes thermal resistance; must tie directly to PCB ground plane to maintain load regulation and limit EMI |
| BIAS (Pin 5) | Efficiency boost supply | When connected to regulated 5V output, shifts internal bias current from VIN to VOUT, improving efficiency by >10% at high VIN/VOUT ratios |
| VC (Pin 6) | Error amp output / current limit input | Controls switch peak current; used for loop compensation; clamp at 2.1V limits maximum duty cycle |
| SENSE (Pin 7) | Fixed 5V output monitor | Replaces FB pin on -5 variants; connects directly to 5V output; triggers foldback if voltage drops below 0.7V |
| SHDN (Pin 8) | Shutdown control | 2.42V UVLO threshold disables switching; 0.37V threshold forces micropower shutdown drawing only 20µA |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology | Enables fast transient response and inherent stability without external compensation components |
| Fused SO-8 ground lead | Reduces θJA to 80°C/W - enables 1.25A continuous output at +85°C ambient without heatsink |
| Integrated slope compensation | Prevents subharmonic oscillation up to 90% duty cycle, allowing stable operation across wide VIN/VOUT ratios |
| Two-stage shutdown logic | Separate 2.42V (UVLO) and 0.37V (micropower) thresholds enable robust input sequencing and battery preservation |
| BOOST-driven NPN switch | Delivers 0.2Ω effective on-resistance using bipolar process - achieves >88% efficiency vs. ~75% in legacy designs |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Core voltage regulation for embedded controllers and peripherals in clamshell notebooks with limited board space and thermal budget. IC Role / Device Role / Timing Role: Primary 5V buck converter supplying USB ports, display backlight drivers, and I/O interfaces. Use Value: Fused SO-8 package and 20µA shutdown current extend battery life during sleep states while maintaining 1.25A delivery capability during active use. | Use Scenario: Power management in handheld test equipment operating from 2-cell Li-ion (6–8.4V) or 9V alkaline batteries. IC Role / Device Role / Timing Role: Main 5V system rail generator with input voltage range covering full battery discharge curve. Use Value: 6V minimum input and 200kHz fixed-frequency operation ensure stable regulation even at end-of-life battery voltage without frequency foldback artifacts. |
| Battery Charger | Distributed Power |
Use Scenario: Auxiliary 5V supply for charging circuitry and microcontroller in multi-bay smart chargers accepting 12–24V DC input. IC Role / Device Role / Timing Role: Isolated secondary-side regulator powering charge management ICs and status LEDs. Use Value: 25V absolute maximum input rating and robust cycle-by-cycle current limiting protect against input transients and output shorts during hot-plug events. | Use Scenario: Local point-of-load conversion in industrial PLC backplanes where 24V bus supplies multiple 5V subsystems. IC Role / Device Role / Timing Role: Compact, thermally efficient 5V regulator mounted directly on module PCBs near load. Use Value: SO-8 fused ground and 80°C/W thermal resistance allow dense placement without thermal derating - critical for fanless distributed architectures. |
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, 1.2A, integrated MOSFETs; no BOOST pin required; 2.5V–5.5V input | Higher frequency enables smaller inductors/caps but unsuitable for 6–25V input range | Select LTC3605EDE#PBF only for low-input-voltage, space-constrained designs where 200kHz EMI profile is unacceptable |
| LM2678SX-5.0/NOPB | 63kHz external-switch buck, 5A, requires external N-channel MOSFET; no integrated BOOST or fused thermal path | Higher current capability but larger solution size and inferior thermal performance in SO-8 footprint | Select LM2678SX-5.0/NOPB only when >1.5A output or adjustable output voltage is required and board area is not constrained |
Compared with LTC3605EDE#PBF and LM2678SX-5.0/NOPB, the LT1576CS8#PBF uniquely combines 6–25V input support, fused-lead SO-8 thermal performance, and BOOST-enabled bipolar efficiency - making it optimal for cost-sensitive, thermally constrained 5V/1.25A applications where input voltage exceeds 5.5V.
Availability
LT1576CS8#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 consistent parametric performance across production batches.
Supply support for LT1576CS8#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 all Linear products, including precision analog and power management ICs.
The LT1576CS8#PBF belongs to Linear's legacy monolithic buck regulator family, designed specifically for noise-sensitive portable and battery-operated applications where thermal efficiency, small solution size, and robust short-circuit protection are critical.
FAQ
What is the maximum continuous output current of the LT1576CS8#PBF at 5V output?
The LT1576CS8#PBF delivers up to 1.25A continuously at 5V output under typical conditions (VIN = 10V, TA ≤ +85°C, with proper PCB thermal design). At higher input voltages (e.g., VIN = 25V), maximum load current decreases due to increased inductor ripple current; actual limit depends on inductor value, ambient temperature, and PCB copper area connected to the fused GND pin.
Does the LT1576CS8#PBF require an external BOOST capacitor and diode?
Yes, the LT1576CS8#PBF requires an external BOOST capacitor (typically 10nF ceramic) and catch diode (e.g., 1N5818) connected between VIN and BOOST pins. This network generates a voltage higher than VIN to saturate the internal NPN switch, achieving the specified 0.2Ω on-resistance and >88% efficiency. Omitting these components results in excessive VCE(sat) and thermal failure.
How does the SENSE pin on the LT1576CS8#PBF differ from the FB pin on adjustable versions?
The LT1576CS8#PBF uses Pin 7 as SENSE - a dedicated input tied directly to the 5V output rail - replacing the FB pin found on adjustable versions. Internally, it connects to a precision 4.94–5.06V comparator with foldback logic. When SENSE voltage drops below 0.7V, the device reduces switching frequency and current limit to protect against short circuits, unlike FB-based versions which rely on external resistor dividers.
Can the LT1576CS8#PBF be synchronized to an external clock?
No, the LT1576CS8#PBF does not support synchronization. It uses Pin 8 as SHDN (shutdown), not SYNC. Synchronization capability is only available on variants marked "-SYNC" (e.g., LT1576CS8-SYNC), where Pin 8 is repurposed as a logic-compatible SYNC input with 250–400kHz locking range. Using an external clock signal on the SHDN pin of the LT1576CS8#PBF will cause erratic shutdown behavior.
What is the purpose of the fused ground lead in the SO-8 package of the LT1576CS8#PBF?
The fused ground lead in the LT1576CS8#PBF's SO-8 package creates a low-thermal-resistance path from the die to the PCB ground plane, achieving θJA = 80°C/W - significantly better than standard SO-8 packages (~150°C/W). This allows the device to sustain 1.25A output current at +85°C ambient without derating, making it suitable for compact, fanless enclosures where thermal headroom is limited.
LT1576CS8#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
- 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:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1576CS8#PBF FAQ
1.How can I place an order for LT1576CS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1576CS8#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 LT1576CS8#PBF reliable?
The price and inventory of LT1576CS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1576CS8#PBF is usually 5 days.
3.What payment methods are accepted for LT1576CS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1576CS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1576CS8#PBF?
LT1576CS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1576CS8#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 LT1576CS8#PBF?
For technical support, including LT1576CS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1576CS8#PBF requirements.
6.How does Aetrix verify that LT1576CS8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1576CS8#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 LT1576CS8#PBF meets industry standards.
7.What is the process for return or replacement of LT1576CS8#PBF?
All LT1576CS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1576CS8#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 LT1576CS8#PBF part is unused and in its original packaging.
Return procedure for LT1576CS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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