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Analog Devices Inc. LT1506IS8#TRPBF
- Part No.:
- LT1506IS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1506IS8#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 4.5A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,607
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Product details
Overview
LT1506IS8#TRPBF from Analog Devices (formerly Linear Technology) is a 500kHz monolithic buck switching regulator with integrated 4.5A NPN power switch, optimized for 4V–15V input and fixed 3.3V output. It features cycle-by-cycle current limiting, 0.07Ω switch on-resistance, 20µA shutdown current, and operates in current-mode control for fast transient response. Used in portable computers and battery-powered systems requiring compact, efficient DC/DC conversion.
For engineers reviewing the LT1506IS8#TRPBF datasheet, LT1506IS8#TRPBF pinout, LT1506IS8#TRPBF application, or LT1506IS8#TRPBF equivalent, key selection criteria include its fixed 3.3V SENSE-pin configuration, fused-ground SO-8 package, 500kHz ±40kHz switching frequency, thermal shutdown protection, and compatibility with surface-mount inductors as small as 1.8µH.
Technical Context
The LT1506IS8#TRPBF implements constant-frequency current-mode control using an internal 500kHz oscillator, error amplifier (2000 µMho transconductance), and peak-current comparator referenced to the SENSE pin. Its BOOST pin enables saturation of the on-die NPN switch via external capacitor-diode network, reducing conduction loss to that of a 0.07Ω FET.
It integrates undervoltage lockout (2.38V threshold), dual-threshold shutdown (0.4V full micropower, 2.38V UVLO), and foldback protection: switching frequency drops below 1V at FB/SENSE, and current limit reduces below 1.7V. The fused-ground SO-8 package provides enhanced thermal dissipation with θJA = 80°C/W.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1.5% (SENSE pin tied directly to output) |
| Switching Frequency | 500kHz ±40kHz; supports synchronization up to 1MHz |
| Max Switch Current | 4.5A at ≤50% duty cycle; derates nonlinearly above 50% DC |
| Switch On Resistance | 0.07Ω typical at 4.5A - enables high efficiency with low conduction loss |
| Shutdown Current | 20µA typical - enables ultra-low-power standby in battery systems |
| Min Input Voltage | 4.0V guaranteed - supports operation down to single-cell Li-ion or 3×AA |
| Thermal Shutdown | Integrated junction-sensing protection - prevents damage during overload or poor heatsinking |
Pinout & Package
LT1506IS8#TRPBF is housed in an 8-lead plastic SO package with fused ground pin (Pin 2) directly connected to the internal tab for improved thermal performance. Pin 2 must be soldered to a large copper area to achieve specified θJA = 80°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Input supply and collector of internal NPN switch | Carries high dI/dt switching current; requires low-inductance path to bypass cap and catch diode |
| BOOST (Pin 2) | Boost drive voltage input | Must be held ≥5V above VIN via external capacitor-diode to saturate NPN switch and minimize VCE(sat) |
| GND (Pin 3) | Power and signal reference ground | Fused pin tied to internal tab; requires direct connection to large copper plane for thermal and EMI control |
| VSW (Pin 4) | Emitter of internal NPN switch | Swings from near VIN (on) to −0.8V (off); drives inductor and connects to cathode of catch diode |
| SYNC (Pin 5) | External clock synchronization input | Logic-compatible (10–90% duty); replaces SHDN on -SYNC variants; unused must be grounded |
| SHDN (Pin 6) | Shutdown control input | 0.4V threshold enables full micropower mode; 2.38V threshold enables precise UVLO |
| VC (Pin 7) | Error amplifier output / current limit setpoint | Used for loop compensation; also serves as current clamp node (0.9V switch threshold, 2.1V upper clamp) |
| SENSE (Pin 8) | Fixed-output voltage sense input | Internally biased to 3.3V; connected directly to output for regulation - no external divider required |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology | Enables fast load transient response and inherent stability with minimal compensation components |
| Integrated BOOST circuitry | Allows NPN switch saturation, achieving 0.07Ω RON and >89% efficiency at 3.3V/4A |
| Two-level shutdown | 0.4V full micropower mode (20µA) + 2.38V accurate UVLO prevent brownout operation |
| Frequency & current foldback | Reduces switching frequency and peak current under short-circuit conditions to limit IC and external component power dissipation |
| Fused-ground SO-8 package | Pin 2 bonded to internal tab; enables reliable thermal management without exposed pad reflow complexity |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Core logic voltage rail in subnotebook or tablet platforms with tight space constraints and dynamic load profiles. IC Role / Device Role / Timing Role: Primary 3.3V buck regulator delivering up to 4A to CPU I/O, memory interfaces, and peripheral controllers. Use Value: Enables use of 1.8µH inductors and eliminates need for external feedback resistors - reducing BOM count and PCB area by >15% vs. adjustable regulators. | Use Scenario: Main power stage in handheld medical devices operating from 2–3 alkaline cells or single Li-ion cell. IC Role / Device Role / Timing Role: Step-down converter maintaining stable 3.3V for microcontroller, sensors, and BLE radio under varying battery discharge curves. Use Value: 4.0V minimum input and 20µA shutdown current extend usable battery life by >20% compared to legacy 5.5V-min regulators. |
| Battery Charger | Distributed Power |
Use Scenario: Auxiliary 3.3V supply in multi-cell Li-ion charger ICs powering fuel gauging, display, and communication circuitry. IC Role / Device Role / Timing Role: Isolated auxiliary rail generator supporting real-time state monitoring and USB interface during charging cycles. Use Value: Integrated foldback protection prevents thermal runaway during charger fault conditions - eliminating need for external current-limiting circuits. | Use Scenario: Local point-of-load regulator on industrial backplanes or modular instrumentation cards requiring clean, regulated 3.3V. IC Role / Device Role / Timing Role: Compact, thermally robust DC/DC stage converting 5V or 12V system rail to 3.3V for FPGA I/O banks or ADC reference supplies. Use Value: Fused-ground SO-8 package delivers 80°C/W thermal resistance without thermal vias - simplifying layout in dense, multi-layer boards. |
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 | 4A synchronous buck, 3MHz switching, integrated MOSFETs, 2.5V–5.5V input | Higher frequency enables smaller inductors/caps but limited to lower VIN range; no BOOST pin or fused-GND SO-8 | Prefer for space-constrained designs needing >1MHz operation and synchronous efficiency; not drop-in for 4–15V input or thermal-limited layouts |
| TPS54331DR | 3A non-synchronous buck, 570kHz, 3.5–28V input, adjustable output, SO-8 package | Wider input range and adjustable VOUT, but lacks fixed 3.3V SENSE option, higher RDS(on), and no fused ground | Prefer when input exceeds 15V or output voltage flexibility is required; requires external feedback divider and has higher thermal resistance |
Compared with LTC3605EDE#TRPBF and TPS54331DR, the LT1506IS8#TRPBF offers unique advantages in 4–15V fixed-3.3V applications: its fused-ground SO-8 delivers superior thermal performance without thermal vias, the BOOST architecture achieves 0.07Ω effective switch resistance, and built-in foldback protection simplifies fault handling in battery systems.
Availability
LT1506IS8#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 consistent parametric performance across temperature.
Supply support for LT1506IS8#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 the LT® product family.
The LT1506IS8#TRPBF belongs to Linear's monolithic buck regulator product line, designed specifically for high-efficiency, low-voltage-input DC/DC conversion in space- and thermal-constrained portable and industrial systems.
FAQ
What is the function of the SENSE pin on the LT1506IS8#TRPBF?
The SENSE pin on the LT1506IS8#TRPBF replaces the FB pin in fixed-output variants and is internally connected to a precision 3.3V reference. It must be tied directly to the regulated output to close the feedback loop - no external resistor divider is needed. This configuration ensures ±1.5% output accuracy over temperature and line/load conditions, and enables the device's current-mode control loop to respond accurately to load transients.
Does the LT1506IS8#TRPBF require an external BOOST capacitor?
Yes, the LT1506IS8#TRPBF requires an external BOOST capacitor (typically 10nF–100nF ceramic) connected between BOOST and VIN pins. This capacitor, charged via an external diode during switch-off time, provides a voltage ≥5V above VIN to fully saturate the internal NPN power switch. Without it, switch conduction loss increases significantly, degrading efficiency and thermal performance - especially at high load currents.
What is the maximum continuous output current supported by the LT1506IS8#TRPBF?
The LT1506IS8#TRPBF supports up to 4A continuous output current at 3.3V under typical conditions (VIN = 5V, L = 5µH, ambient ≤40°C, proper PCB layout). Peak switch current is rated at 4.5A ≤50% duty cycle, but actual max load current depends on input voltage, inductor value, and thermal management. At VIN = 12V, max output current drops to ~3.5A due to increased ripple current and duty-cycle derating.
How does the shutdown functionality work on the LT1506IS8#TRPBF?
The LT1506IS8#TRPBF features dual-threshold shutdown: applying <0.4V to SHDN forces full micropower mode (20µA supply current), while >2.38V disables switching entirely as a precise undervoltage lockout (UVLO). Between these thresholds, the device remains operational. This design allows flexible control - e.g., using a resistor divider from VIN to trigger UVLO at a system-defined input voltage, or driving SHDN directly from a microcontroller GPIO for on/off control.
Can the LT1506IS8#TRPBF synchronize to an external clock?
Yes, the LT1506IS8#TRPBF can synchronize to an external clock via the SYNC pin (Pin 5), which accepts logic-level signals (10–90% duty cycle) from 580kHz to 1MHz. When synchronized, the internal oscillator locks to the external frequency, reducing EMI by eliminating beat frequencies. If SYNC is unused, it must be grounded - leaving it floating may cause erratic operation or increased noise.
LT1506IS8#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):
- 4V
- Voltage - Input (Max):
- 15V
- Voltage - Output (Min/Fixed):
- 2.42V
- Voltage - Output (Max):
- 13.95V
- Current - Output:
- 4.5A
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1506IS8#TRPBF FAQ
1.How can I place an order for LT1506IS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1506IS8#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 LT1506IS8#TRPBF reliable?
The price and inventory of LT1506IS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1506IS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1506IS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1506IS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1506IS8#TRPBF?
LT1506IS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1506IS8#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 LT1506IS8#TRPBF?
For technical support, including LT1506IS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1506IS8#TRPBF requirements.
6.How does Aetrix verify that LT1506IS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1506IS8#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 LT1506IS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1506IS8#TRPBF?
All LT1506IS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1506IS8#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 LT1506IS8#TRPBF part is unused and in its original packaging.
Return procedure for LT1506IS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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