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Analog Devices Inc. LT1506CS8-3.3#TRPBF
- Part No.:
- LT1506CS8-3.3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1506CS8-3.3#TRPBF.pdf
- Description:
- IC REG BUCK 3.3V 4.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,098
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Product details
Overview
LT1506CS8-3.3#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic 500kHz current-mode buck switching regulator with fixed 3.3V output, integrated 4.5A NPN power switch, 0.07Ω on-resistance, and operation down to 4V input. It delivers up to 4A continuous load current in compact SO-8 packaging and is used in portable computers and battery-powered systems requiring high-efficiency DC/DC conversion.
For engineers reviewing the LT1506CS8-3.3#TRPBF datasheet, LT1506CS8-3.3#TRPBF pinout, LT1506CS8-3.3#TRPBF application, or LT1506CS8-3.3#TRPBF equivalent, key selection criteria include minimum input voltage (4.0V), fixed 3.3V output tolerance (±1.5%), shutdown current (≤50µA), thermal shutdown protection, and compatibility with standard surface-mount inductors as small as 1.8µH.
Technical Context
The LT1506CS8-3.3#TRPBF implements constant-frequency current-mode control with cycle-by-cycle peak current limiting and internal slope compensation to prevent subharmonic oscillation. Its bipolar NPN switch uses BOOST-pin-driven saturation for low conduction loss, enabling >89% efficiency at 5V-to-3.3V conversion.
It features dual shutdown thresholds (0.37V start-up, 2.38V UVLO lockout), SENSE pin direct connection to output for fixed-voltage regulation, and thermal shutdown at 125°C junction temperature. The device operates across 0°C to 125°C ambient (C-grade) and supports optional synchronization via SYNC pin (replacing SHDN in -SYNC variants - not applicable to this -3.3 variant).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1.5% (guaranteed over line, load, temp) |
| Switching Frequency | 500kHz ±8% (enables compact 1.8–10µH inductor selection) |
| Max Output Current | 4A continuous (at VIN ≥5V, L=5µH, TA≤70°C) |
| Input Voltage Range | 4.0V to 15V (supports single-cell Li-ion + boost or 5V rail inputs) |
| Shutdown Current | ≤50µA (enables ultra-low-power standby in battery systems) |
| Switch On-Resistance | 0.07Ω typical (limits conduction loss to <120mW at 4A) |
| Thermal Shutdown | 125°C junction (protects against sustained overload or poor heatsinking) |
Pinout & Package
LT1506CS8-3.3#TRPBF is housed in an 8-lead plastic SOIC (SO-8) package with fused GND pin connected to internal tab for enhanced thermal performance (θJA = 80°C/W). GND pin must be soldered to large copper area for reliable thermal dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power switch collector & IC supply input | Connects to input source; requires local 100µF solid tantalum bypass; high dI/dt node |
| BOOST | Switch driver voltage boost node | Must be biased 5V above VIN via external capacitor/diode to saturate NPN switch |
| GND | Reference ground & thermal tab connection | Fused pin tied to internal tab; requires low-inductance connection to PCB ground plane |
| VSW | Power switch emitter | Drives inductor; swings negative during off-time; clamped by external catch diode |
| SENSE | Fixed-output voltage sense input | Direct connection to 3.3V output; replaces FB pin in -3.3 variants; sets regulation point |
| VC | Error amplifier output & current limit comparator input | Used for loop compensation; voltage ranges ~1V (light load) to ~2V (full load) |
| SHDN | Enable/disable control input | Logic-low (<0.6V) disables switching; ≤20µA quiescent draw in shutdown |
| NC | No connect | Pin 1 is unconnected; no internal bond wire; leave floating or omit trace |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 4.5A NPN power switch | Eliminates external MOSFET and gate driver; reduces BOM count and layout complexity |
| Current-mode control architecture | Provides inherent cycle-by-cycle current limiting and fast transient response without external compensation |
| BOOST-pin saturation drive | Reduces effective switch RCE(sat) to 0.07Ω, enabling >89% efficiency at 5V→3.3V/4A |
| Two-threshold shutdown logic | 0.37V enables startup; 2.38V provides accurate undervoltage lockout (UVLO) to prevent brownout operation |
| Thermal shutdown with hysteresis | Shuts down at 125°C junction; restarts after ~15°C cooldown; prevents thermal runaway under overload |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Core voltage regulation for low-power microcontrollers and I/O peripherals in clamshell notebooks and tablets. IC Role / Device Role / Timing Role: Primary 3.3V buck converter supplying SoC subsystems; replaces discrete switcher solutions. Use Value: Enables 4A output from 4–5.5V battery sources with <1.5% output tolerance and <50µA shutdown current for extended sleep mode. | Use Scenario: Power management in handheld test equipment, medical sensors, and wireless data loggers. IC Role / Device Role / Timing Role: Main system regulator converting single Li-ion (3.0–4.2V) or two-AA (2.4–3.2V with boost) to stable 3.3V rail. Use Value: Supports operation down to 4.0V input, allowing full utilization of battery capacity before cutoff; thermal shutdown protects against enclosure overheating. |
| Battery Charger | Distributed Power |
Use Scenario: Auxiliary 3.3V supply for charger controller ICs, status LEDs, and USB interface circuitry in multi-cell Li-ion chargers. IC Role / Device Role / Timing Role: Secondary regulator powered from main charger output (e.g., 5V or 12V bus); isolated from charging path. Use Value: Delivers clean, regulated 3.3V at up to 4A with minimal external components-no external feedback divider required due to fixed SENSE configuration. | Use Scenario: Local point-of-load (POL) conversion in industrial PLC modules and telecom line cards where centralized 5V/12V rails feed distributed 3.3V logic. IC Role / Device Role / Timing Role: Compact, self-contained buck stage mounted near FPGA or ASIC; minimizes IR drop and noise coupling. Use Value: SO-8 footprint allows dense placement; 500kHz switching enables use of 3.3–5µH shielded inductors under 3mm height for space-constrained modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EMSE-3.3#PBF | 4A synchronous buck; 3MHz switching; integrated MOSFETs; 2.7–5.5V input | Requires lower input voltage; better suited for ultra-compact designs with ceramic inductors <1µH | Select when board space is critical and input is limited to 2.7–5.5V; not suitable for 12V input rails. |
| TPS54331DR | 3A non-synchronous buck; 570kHz; 3.5–28V input; adjustable output only | Needs external feedback resistors; lacks fixed 3.3V SENSE pin; higher min input (3.5V) | Choose for wider input range (up to 28V) and cost-sensitive designs where 3A output suffices. |
Compared with LTC3605EMSE-3.3#PBF and TPS54331DR, the LT1506CS8-3.3#TRPBF offers higher current (4.5A switch), fixed 3.3V SENSE interface eliminating resistor networks, and proven robustness in 4–15V industrial input ranges-but requires external catch diode and BOOST capacitor unlike fully integrated synchronous alternatives.
Availability
LT1506CS8-3.3#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 guaranteed traceable sourcing.
Supply support for LT1506CS8-3.3#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 technical and manufacturing continuity for legacy Linear power products.
The LT1506 product line was designed for high-current, low-input-voltage buck conversion in space-constrained portable and battery-operated equipment, emphasizing thermal robustness, minimal external component count, and seamless integration with standard surface-mount magnetics.
FAQ
What is the minimum input voltage specification for LT1506CS8-3.3#TRPBF?
The LT1506CS8-3.3#TRPBF has a guaranteed minimum input voltage of 4.0V, verified across temperature and process corners. Below this, internal bias regulation fails and output voltage becomes unregulated. At 4.0V input and 3.3V output, maximum load current drops to ~2.8A (L=5µH), per Typical Performance Characteristics Figure G13. Operation at exactly 4.0V requires careful thermal design due to reduced headroom.
Does LT1506CS8-3.3#TRPBF require an external catch diode, and what type is recommended?
Yes, LT1506CS8-3.3#TRPBF requires an external Schottky catch diode connected between VSW and GND. The MBRS330T3 (30V, 3A, 0.45V VF) is explicitly recommended in the datasheet schematic (Figure TA01). A 3A-rated diode is sufficient for 4A output because peak inductor current remains below 4.5A under normal conditions, and foldback limits short-circuit current.
How does the BOOST pin function in LT1506CS8-3.3#TRPBF, and what external components are needed?
The BOOST pin in LT1506CS8-3.3#TRPBF supplies elevated drive voltage to saturate the internal NPN switch, reducing effective on-resistance to 0.07Ω. It requires a flying capacitor (typically 10nF–100nF ceramic) and a Schottky diode (e.g., 1N5817) from VIN to BOOST. During switch-on, the capacitor charges to VIN; during switch-off, it lifts BOOST to ~VIN + Vcap, enabling full saturation and high efficiency.
What is the purpose of the SENSE pin on LT1506CS8-3.3#TRPBF, and how is it connected?
The SENSE pin on LT1506CS8-3.3#TRPBF replaces the FB pin in adjustable variants and is internally connected to a precision 2.42V reference. It must be connected directly to the regulated 3.3V output node-never through a resistor or ferrite bead-to ensure accurate closed-loop regulation. This eliminates external feedback dividers and improves load regulation by referencing the output at the IC's sense point.
Is LT1506CS8-3.3#TRPBF RoHS compliant and lead-free?
Yes, LT1506CS8-3.3#TRPBF is RoHS compliant and lead-free. The #TRPBF suffix denotes tape-and-reel packaging, Pb-free (lead-free) finish, and adherence to JEDEC J-STD-020 moisture sensitivity level 3 (MSL3). The SO-8 package uses matte tin plating over copper leadframe, qualified for reflow up to 260°C peak.
LT1506CS8-3.3#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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 15V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 4.5A
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1506CS8-3.3#TRPBF FAQ
1.How can I place an order for LT1506CS8-3.3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1506CS8-3.3#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 LT1506CS8-3.3#TRPBF reliable?
The price and inventory of LT1506CS8-3.3#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1506CS8-3.3#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1506CS8-3.3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1506CS8-3.3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1506CS8-3.3#TRPBF?
LT1506CS8-3.3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1506CS8-3.3#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 LT1506CS8-3.3#TRPBF?
For technical support, including LT1506CS8-3.3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1506CS8-3.3#TRPBF requirements.
6.How does Aetrix verify that LT1506CS8-3.3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1506CS8-3.3#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 LT1506CS8-3.3#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1506CS8-3.3#TRPBF?
All LT1506CS8-3.3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1506CS8-3.3#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 LT1506CS8-3.3#TRPBF part is unused and in its original packaging.
Return procedure for LT1506CS8-3.3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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