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Analog Devices Inc. LT1506CR#PBF
- Part No.:
- LT1506CR#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LT1506CR#PBF.pdf
- Description:
- IC REG BUCK ADJ 4.5A DDPAK-7
- Quantity:
- Payment:
- Shipping:
Inventory:2,008
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Product details
Overview
LT1506CR#PBF from Analog Devices (formerly Linear Technology) is a 4.5A, 500kHz monolithic buck switching regulator in SO-8 package with fixed 3.3V output, cycle-by-cycle current limiting, and shutdown functionality. It operates from 4V to 15V input, delivers up to 4A at 3.3V, and targets battery-powered systems requiring compact, high-efficiency DC/DC conversion.
For engineers reviewing the LT1506CR#PBF datasheet, LT1506CR#PBF pinout, LT1506CR#PBF application, or LT1506CR#PBF equivalent, key selection factors include its 0.07Ω switch RDS(on), 20µA shutdown current, 3.3V ±1.5% output accuracy, thermal shutdown protection, and compatibility with standard surface-mount inductors as small as 1.8µH.
Technical Context
The LT1506CR#PBF implements current-mode control with an internal 500kHz oscillator, enabling fast transient response and stable loop behavior across wide load and line variations. Its bipolar NPN power switch uses BOOST-pin-driven saturation for low conduction loss, while integrated slope compensation prevents subharmonic oscillation above 50% duty cycle.
It features dual-threshold shutdown (0.37V start-up / 0.60V full shutdown), lockout at 2.38V, and SENSE pin monitoring for fixed 3.3V regulation. The VC pin serves as error amplifier output and current-limit comparator input, supporting external compensation and current clamping.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1.5% (guaranteed over temperature and line) |
| Switch Current Limit | 4.5A typical (derates nonlinearly above 50% duty cycle) |
| Switch On Resistance | 0.07Ω typical (enables >89% efficiency at 4A, 5V→3.3V) |
| Shutdown Current | 20µA typical (reduces system standby power in portable devices) |
| Switching Frequency | 500kHz ±8% (allows use of <10µH inductors; reduces EMI fundamental) |
| Input Voltage Range | 4.0V to 15V (supports single-cell Li-ion + boost or 5V rail with margin) |
| Thermal Shutdown | Activated at 125°C junction (protects against sustained overload or poor heatsinking) |
Pinout & Package
LT1506CR#PBF is housed in an 8-lead plastic SOIC (SO-8) package with fused GND pin attached to internal tab for enhanced thermal performance (θJA = 80°C/W). GND pin must be connected to large copper area for optimal thermal dissipation and EMI control.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input voltage supply and NPN collector | Supplies internal circuitry and powers switch; requires low-inductance bypass near pin |
| BOOST | Boost capacitor drive node | Provides >VIN voltage to saturate NPN switch; enables 0.07Ω effective RDS(on) |
| GND | Power and signal reference ground | Fused pin tied to internal tab; must connect to large copper plane for thermal/EMI control |
| VSW | NPN emitter switch node | Drives inductor; swings negative during off-time; requires catch diode clamp |
| SYNC | Oscillator synchronization input | Replaces SHDN on -SYNC variants; logic-compatible input (10–90% duty cycle, up to 1MHz) |
| SHDN | Shutdown control input | 0.37V threshold starts operation; 0.60V fully disables switch; 2.38V enables UVLO |
| VC | Error amplifier output / current limit comparator input | 1–2V range under load; supports external compensation and current override |
| SENSE | Fixed-output voltage feedback | Direct connection to 3.3V output; replaces FB pin on adjustable variants |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology | Enables stable operation with ceramic output capacitors and fast load-step response (<10µs) |
| BOOST-driven saturation | Reduces switch conduction loss vs. conventional bipolar designs, improving efficiency by ≥14% |
| Cycle-by-cycle current limiting | Prevents switch damage during short-circuit or overload without external sensing components |
| Frequency foldback | Reduces switching frequency 5:1 when output collapses, limiting power dissipation in IC and external components |
| Integrated thermal shutdown | Protects device during sustained overload or inadequate PCB copper; auto-recovers after cooldown |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Core voltage regulation for low-power microcontrollers and peripherals in clamshell notebooks. IC Role / Device Role / Timing Role: Primary 3.3V buck converter delivering up to 4A with tight output tolerance and low quiescent current. Use Value: Enables >89% efficiency at full load and 20µA shutdown current, extending battery runtime between charges. | Use Scenario: Power management in handheld test equipment with variable battery input (4–15V). IC Role / Device Role / Timing Role: Input-flexible step-down regulator maintaining stable 3.3V rail despite Li-ion voltage sag. Use Value: Minimum 4.0V input operation allows usable battery capacity down to ~3.6V cell voltage before cutoff. |
| Battery Charger | Distributed Power |
Use Scenario: Auxiliary 3.3V supply for charger controller ICs and status LEDs in multi-bay Li-ion chargers. IC Role / Device Role / Timing Role: Secondary regulated rail isolated from main charging path, powered from intermediate bus. Use Value: Cycle-by-cycle current limiting and thermal shutdown prevent fault propagation during cell mismatch or shorted battery conditions. | Use Scenario: Local point-of-load regulation on industrial I/O modules with 12V backplane input. IC Role / Device Role / Timing Role: Compact, surface-mount DC/DC converter replacing discrete buck solutions with higher BOM count. Use Value: SO-8 footprint and all-SMT external parts reduce board area by ≥40% vs. through-hole alternatives. |
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, 3MHz synchronous buck; 2.5–5.5V input; integrated MOSFETs; no BOOST pin required | Higher frequency enables smaller inductors but tighter layout constraints; lacks 4V min input support | Preferred for space-constrained designs where input stays ≥2.5V; not suitable for 4V battery start-up |
| TPS54331DR | 3A, 570kHz nonsynchronous buck; 3.5–28V input; external diode; 0.13Ω high-side RDS(on) | Wider input range but higher dropout and lower max current; no frequency foldback or dual-threshold shutdown | Acceptable for 5V-input systems with moderate load; inferior protection and efficiency below 5V input |
Compared with LT1506CR#PBF, LTC3605EDE#TRPBF offers higher integration and frequency but sacrifices 4V start-up capability and BOOST-assisted efficiency, while TPS54331DR provides broader input range but lacks critical protections and delivers lower current with higher conduction loss.
Availability
LT1506CR#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 traceable sourcing.
Supply support for LT1506CR#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 its high-performance analog and power management product lines.
The LT1506CR#PBF belongs to Linear's monolithic buck regulator family designed for high-efficiency, low-voltage DC/DC conversion in space- and power-constrained applications.
FAQ
What is the minimum input voltage required for LT1506CR#PBF to regulate 3.3V output?
The LT1506CR#PBF guarantees regulation down to 4.0V input under all conditions, verified by internal bias regulation tests. At 3.3V output, practical minimum input is ~4.2V at full 4A load due to dropout across the 0.07Ω switch and inductor DCR. Below 4.0V, the device enters undervoltage lockout and ceases switching. This makes LT1506CR#PBF suitable for single-cell Li-ion systems with boost converters or partially discharged batteries.
Does LT1506CR#PBF require an external catch diode, and what type is recommended?
Yes, LT1506CR#PBF requires an external Schottky catch diode connected between VSW and GND. The MBRS330T3 (30V, 3A) is explicitly recommended in the datasheet for 5V→3.3V conversion. Its low forward voltage (≤0.45V) minimizes conduction loss and improves efficiency, while fast recovery prevents reverse recovery spikes. For higher input voltages, select a diode rated ≥1.2× VIN with comparable IF(AV) and trr < 50ns.
How does the BOOST pin function in LT1506CR#PBF, and what external components are needed?
The BOOST pin in LT1506CR#PBF drives an external capacitor-diode charge pump to generate a voltage ~5V above VIN, which saturates the internal NPN switch and achieves 0.07Ω effective on-resistance. Required components are a 1.5nF ceramic capacitor (CC) from BOOST to VIN and a Schottky diode (e.g., 1N5817) from VIN to BOOST. Incorrect BOOST implementation causes elevated switch loss and reduced efficiency - the LT1506CR#PBF will not operate correctly without this network.
Can LT1506CR#PBF be synchronized to an external clock, and how is it configured?
LT1506CR#PBF does not support synchronization because it uses the standard SO-8 pinout with SHDN on pin 5. Synchronization is only available on -SYNC variants (e.g., LT1506CR-SYNC), where SHDN is replaced by SYNC on pin 5. Attempting to drive SYNC functionality on LT1506CR#PBF will result in unintended shutdown. For synchronized operation, specify LT1506CR-SYNC or redesign with compatible pinout - LT1506CR#PBF itself has no SYNC capability.
What is the purpose of the SENSE pin on LT1506CR#PBF, and how does it differ from FB?
The SENSE pin on LT1506CR#PBF replaces the FB pin used on adjustable versions and connects directly to the 3.3V output to close the regulation loop. Unlike FB, which requires an external resistor divider to set voltage, SENSE eliminates external components and ensures ±1.5% output accuracy over temperature and line. Internally, it references the same 2.42V bandgap but bypasses the divider network - making LT1506CR#PBF a drop-in solution for fixed 3.3V applications without calibration or trimming.
LT1506CR#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Packaging:
- Tube
- 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:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DDPAK-7
LT1506CR#PBF FAQ
1.How can I place an order for LT1506CR#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1506CR#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 LT1506CR#PBF reliable?
The price and inventory of LT1506CR#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1506CR#PBF is usually 5 days.
3.What payment methods are accepted for LT1506CR#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1506CR#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1506CR#PBF?
LT1506CR#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1506CR#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 LT1506CR#PBF?
For technical support, including LT1506CR#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1506CR#PBF requirements.
6.How does Aetrix verify that LT1506CR#PBF is sourced from the original manufacturer or authorized distributors?
All LT1506CR#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 LT1506CR#PBF meets industry standards.
7.What is the process for return or replacement of LT1506CR#PBF?
All LT1506CR#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1506CR#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 LT1506CR#PBF part is unused and in its original packaging.
Return procedure for LT1506CR#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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