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Analog Devices Inc. LT1576CS8#TRPBF
- Part No.:
- LT1576CS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1576CS8#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,692
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Product details
Overview
LT1576CS8#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 range 6V–25V, cycle-by-cycle current limiting, and shutdown functionality. Used in portable computers and battery-powered systems requiring compact, efficient DC/DC conversion.
For engineers reviewing the LT1576CS8#TRPBF datasheet, LT1576CS8#TRPBF pinout, LT1576CS8#TRPBF application, or LT1576CS8#TRPBF equivalent, key selection criteria include its 200kHz fixed-frequency current-mode architecture, 0.2Ω switch on-resistance, 1.21V feedback reference (or 5.0V SENSE for -5 variant), 20µA shutdown current, and SO-8 thermal performance enabled by fused ground lead.
Technical Context
The LT1576CS8#TRPBF implements a constant-frequency, current-mode buck topology with internal oscillator, error amplifier (1000 µMho transconductance), and peak-current comparator. Its modified LT1376 architecture features slowed switch transitions to reduce EMI, nonlinear slope compensation for stable operation up to 94% duty cycle, and dual-threshold shutdown (0.37V active shutdown, 2.44V UVLO).
It supports BIAS pin operation for improved efficiency at high VIN/light loads, BOOST pin drive for NPN saturation (reducing switch loss), and optional synchronization via SYNC pin (replacing SHDN in -SYNC variants). The -5 suffix indicates fixed 5V output with SENSE pin instead of FB, confirmed for LT1576CS8#TRPBF per ordering table and pin function documentation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.2% (SENSE pin monitoring; no external divider required) |
| Switching Frequency | 200kHz ±10% (fixed, current-mode; foldback to ~40kHz under short-circuit) |
| Max Output Current | 1.25A continuous (at VOUT=5V, VIN=10V, L=33µH; derates with higher VIN or smaller inductor) |
| Switch On Resistance | 0.2Ω typical (enables >88% efficiency vs. ~75% in standard bipolar designs) |
| Shutdown Current | 20µA max (ensures ultra-low quiescent drain during standby) |
| Reference Voltage | 1.21V nominal (internal bandgap; used for SENSE threshold and regulation accuracy) |
| Input Voltage Range | 6V to 25V (minimum validated at 5.5V; requires BOOST ≥2.3V above VIN) |
| Thermal Resistance | θJA = 80°C/W (achieved via fused ground lead connected to PCB ground plane) |
Pinout & Package
LT1576CS8#TRPBF uses an 8-lead plastic SOIC (SO-8) package with fused ground lead for enhanced thermal performance. Pin 4 (GND) must be connected directly to a low-impedance ground plane to ensure load regulation and minimize EMI from VSW-GND displacement current.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW (Pin 1) | Switch emitter | Drives inductor; clamped negative during off-time by external catch diode; max –0.8V allowed |
| VIN (Pin 2) | Switch collector & bias source | Powers internal circuitry when BIAS pin is open; high dI/dt node requiring local bypass capacitor |
| BOOST (Pin 3) | Bootstrap drive voltage | Provides >VIN voltage to saturate NPN switch; requires external capacitor + diode (e.g., 1N5818) |
| GND (Pin 4) | Power & signal reference | Fused lead reduces θJA; must tie directly to ground plane to avoid load regulation error and EMI radiation |
| BIAS (Pin 5) | Efficiency optimization input | Connect to VOUT ≥3.3V to shift bias current from VIN, improving efficiency at high VIN/light loads |
| VC (Pin 6) | Error amp output / current limit control | Sets switch current trip point; 0.8V threshold disables switching; 2.1V clamp limits max duty cycle |
| SENSE (Pin 7) | Fixed-output voltage monitor | Replaces FB on -5 variants; connects directly to 5V output; triggers foldback if <0.7V |
| SHDN (Pin 8) | Enable/disable control | 0.37V threshold enables full shutdown (20µA IQ); 2.44V threshold enables UVLO lockout |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode control | Enables fast transient response and inherent loop stability without external compensation complexity |
| Fused SO-8 ground lead | Reduces thermal resistance to 80°C/W, extending ambient operating range and enabling 1.25A continuous output |
| EMI-optimized switching | Slowed switch transitions and isolated high-/low-current routing minimize radiated emissions |
| Cycle-by-cycle current limiting | Protects switch and external components during overload/short-circuit with automatic foldback |
| BIAS pin efficiency boost | Redirects internal bias current from VIN to VOUT, improving efficiency by >10% at VIN=20V, VOUT=5V, IOUT=25mA |
| Nonlinear slope compensation | Maintains stability across wide duty cycle range (8%–94%) while preserving current limit headroom |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Powering core logic and I/O rails in notebook PCs with 12V or 19V battery packs. IC Role / Device Role / Timing Role: Primary 5V buck converter delivering regulated supply to USB controllers, display interfaces, and embedded controllers. Use Value: High efficiency (>88%) extends battery runtime; fused SO-8 package ensures thermal reliability under sustained 1.25A load. | Use Scenario: Providing stable 5V rail for handheld test equipment powered by Li-ion or alkaline batteries. IC Role / Device Role / Timing Role: Main DC/DC regulator converting variable battery voltage (6–25V) to fixed 5V for microcontroller and sensor subsystems. Use Value: 20µA shutdown current preserves battery life during sleep mode; wide input range accommodates battery discharge curve. |
| Battery Charger | Distributed Power |
Use Scenario: Generating 5V auxiliary supply in multi-cell Li-ion charger modules for status LEDs, communication ICs, and fan control. IC Role / Device Role / Timing Role: Secondary regulator deriving clean 5V from main charging bus (e.g., 12–24V DC input). Use Value: Cycle-by-cycle current limiting prevents damage during charger fault conditions; BOOST pin ensures consistent switch saturation across input range. | Use Scenario: Local point-of-load conversion in industrial PLC backplanes where 24V system rail powers isolated 5V logic domains. IC Role / Device Role / Timing Role: Compact, thermally robust buck regulator mounted directly on module PCBs for distributed 5V generation. Use Value: Fused ground lead and SO-8 footprint enable reliable thermal management without heatsinks; synchronization capability allows noise-sensitive timing domains to align switching edges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 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 | Higher frequency enables smaller inductors/caps; not suitable for 6–25V input range; lacks BOOST/SYNC flexibility | Select LTC3605EDE#TRPBF only for low-input-voltage, high-density designs needing >1.25A; not drop-in for LT1576CS8#TRPBF's input range or thermal profile. |
| LM2678SD-5.0/NOPB | 63kHz buck, 5A output, external diode; 8–40V input; 5V fixed; no BIAS/BOOST pins; SO-8 package | Lower switching frequency increases inductor size; no efficiency-boost BIAS pin; higher quiescent current (50mA vs. 1.16mA) | Choose LM2678SD-5.0/NOPB for higher current needs where board space allows larger magnetics and thermal design tolerates higher IQ. |
Compared with LTC3605EDE#TRPBF and LM2678SD-5.0/NOPB, LT1576CS8#TRPBF uniquely balances 6–25V input compatibility, 200kHz EMI-optimized operation, fused-lead thermal performance, and BIAS/BOOST features-making it optimal for mid-power industrial and portable applications where input range and thermal reliability are critical.
Availability
LT1576CS8#TRPBF 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 LT1576CS8#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, Inc. (acquired Linear Technology in 2017) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and power management ICs.
The LT1576 product line was designed for noise-sensitive, medium-power DC/DC conversion in portable and industrial equipment, emphasizing thermal robustness, EMI reduction, and flexible biasing via the BIAS and BOOST pins.
FAQ
What is the output voltage configuration of the LT1576CS8#TRPBF?
The LT1576CS8#TRPBF is the fixed 5V output variant (-5 suffix), using the SENSE pin (Pin 7) connected directly to the output instead of a feedback divider. Its output is precisely regulated to 5.0V ±1.2% over temperature and line, with internal resistors replacing external R1/R2. This eliminates layout sensitivity and improves accuracy versus adjustable versions.
Does the LT1576CS8#TRPBF require an external catch diode?
Yes, the LT1576CS8#TRPBF requires an external Schottky catch diode (e.g., 1N5818) between VSW and GND. As an NPN-based buck controller, it lacks synchronous rectification and relies on this diode to provide the inductor freewheeling path during switch-off time. Diode selection must account for peak current (≥1.5A) and reverse voltage rating (>VIN).
How does the BOOST pin function in the LT1576CS8#TRPBF?
The BOOST pin (Pin 3) provides a voltage higher than VIN to the internal NPN switch base driver, enabling full saturation and reducing conduction loss to ~0.2Ω. It requires an external bootstrap capacitor (e.g., 100pF) and diode (e.g., 1N5818) from VIN to BOOST. Without proper BOOST operation, switch losses increase significantly, degrading efficiency and thermal performance.
What is the purpose of the BIAS pin on the LT1576CS8#TRPBF?
The BIAS pin (Pin 5) allows the LT1576CS8#TRPBF to draw internal bias current from the regulated output (≥3.3V) instead of VIN. When connected to VOUT, it reduces total input-referred supply current-e.g., from 1.16mA to ~0.55mA at VIN=15V-improving efficiency by >10% in high-VIN, light-load scenarios like standby modes in portable devices.
Can the LT1576CS8#TRPBF be synchronized to an external clock?
No-the LT1576CS8#TRPBF has SHDN (shutdown) on Pin 8, not SYNC. Synchronization is only available on -SYNC variants (e.g., LT1576CS8-SYNC), where Pin 8 is repurposed as SYNC. For LT1576CS8#TRPBF, Pin 8 functions exclusively as a dual-threshold shutdown control (0.37V active shutdown, 2.44V UVLO), and external sync capability is not supported.
LT1576CS8#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:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1576CS8#TRPBF FAQ
1.How can I place an order for LT1576CS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1576CS8#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 LT1576CS8#TRPBF reliable?
The price and inventory of LT1576CS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1576CS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1576CS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1576CS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1576CS8#TRPBF?
LT1576CS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1576CS8#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 LT1576CS8#TRPBF?
For technical support, including LT1576CS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1576CS8#TRPBF requirements.
6.How does Aetrix verify that LT1576CS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1576CS8#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 LT1576CS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1576CS8#TRPBF?
All LT1576CS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1576CS8#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 LT1576CS8#TRPBF part is unused and in its original packaging.
Return procedure for LT1576CS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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