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Analog Devices Inc. LT1506CR-3.3#PBF
- Part No.:
- LT1506CR-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LT1506CR-3.3#PBF.pdf
- Description:
- IC REG BUCK 3.3V 4.5A DDPAK-7
- Quantity:
- Payment:
- Shipping:
Inventory:3,720
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Product details
Overview
LT1506CR-3.3#PBF from Analog Devices (formerly Linear Technology) is a fixed 3.3V, 4.5A monolithic synchronous-buck switching regulator in SO-8 package with 500kHz constant-frequency current-mode control, 4V minimum input voltage, 0.07Ω switch on-resistance, and integrated cycle-by-cycle current limiting - used in portable computers and battery-powered systems for high-efficiency DC/DC conversion.
For engineers reviewing the LT1506CR-3.3#PBF datasheet, LT1506CR-3.3#PBF pinout, LT1506CR-3.3#PBF application, or LT1506CR-3.3#PBF equivalent, key selection considerations include its fixed 3.3V output, 4.5A switch rating, 500kHz switching frequency, shutdown current of 20µA, and SENSE pin interface replacing FB for precision output sensing.
Technical Context
The LT1506CR-3.3#PBF implements current-mode control with an internal 500kHz oscillator, peak-current sensing via SENSE pin, and error amplifier output at VC pin driving the switch comparator. Its BOOST pin enables saturation of the integrated NPN power switch, achieving low 0.07Ω on-resistance and >89% efficiency at 5V-to-3.3V conversion.
It features dual-threshold shutdown (0.4V for micropower off, 2.38V for UVLO), cycle-by-cycle current limiting up to 4.5A at ≤50% duty cycle, and thermal shutdown. The fixed-output variant replaces FB with SENSE connected directly to VOUT for accurate 3.3V regulation (±1.5% over temperature).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1.5% over temperature and line/load - eliminates external feedback divider and improves accuracy vs adjustable variants. |
| Switch Current Limit | 4.5A typical at ≤50% duty cycle - sets maximum deliverable load current before foldback activation under short-circuit conditions. |
| Switching Frequency | 500kHz nominal (460–540kHz) - enables compact 1.8µH inductor and reduces size of input/output capacitors. |
| Input Voltage Range | 4V to 15V - supports single-cell Li-ion (4.2V fully charged) and multi-cell battery inputs without pre-regulation. |
| Shutdown Current | 20µA typical - allows ultra-low-power standby in portable systems with no external bias circuitry required. |
| Switch On-Resistance | 0.07Ω typical at 4.5A - minimizes conduction loss and enables >89% efficiency at 5V→3.3V/4A operation. |
| SENSE Pin Voltage | 3.3V ±0.05V (3.25–3.35V) - direct connection to output provides precise regulation without resistor tolerance drift. |
Pinout & Package
LT1506CR-3.3#PBF is housed in an 8-lead plastic SO package (SO-8) with fused GND pin attached to internal tab for enhanced thermal performance (θJA = 80°C/W). GND pin must be soldered to large copper area for thermal management and low-impedance return path.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply collector node | Connects to input capacitor and catch diode anode; high dI/dt node requiring short, low-inductance layout. |
| BOOST | Switch driver boost voltage | Requires external capacitor + diode to generate ~VIN+5V; enables NPN saturation and low 0.07Ω RON. |
| GND | Power and signal reference | Fused lead tied to internal tab; must connect to ground plane for thermal dissipation and stable regulation. |
| VSW | Switch emitter node | Drives inductor; swings negative during off-time - requires external catch diode clamped to −0.8V max. |
| SYNC | Oscillator synchronization input | Logic-compatible (10–90% duty); accepts 580kHz–1MHz external clock - replaces SHDN on -SYNC variants. |
| SHDN | Enable/disable control | 0.4V threshold forces micropower shutdown (20µA); 2.38V threshold enables UVLO lockout. |
| VC | Error amplifier output / current clamp | Controls peak switch current; sits at ~1V (light load) to ~2V (full load); can be overridden for current limiting. |
| SENSE | Fixed-output voltage sense | Replaces FB pin; connected directly to 3.3V output for precise regulation - no external resistors needed. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode topology | Enables fast transient response and inherent loop stability without complex compensation - simplifies design for variable loads. |
| Integrated BOOST drive | Eliminates need for external gate driver; achieves 0.07Ω switch RON and >89% efficiency at full load. |
| Cycle-by-cycle current limiting | Prevents switch damage during overload or short-circuit by limiting peak current every switching cycle. |
| Thermal shutdown protection | Halts operation when junction temperature exceeds 125°C - prevents permanent damage under sustained overload. |
| Frequency foldback under fault | Reduces switching frequency 5:1 when SENSE voltage drops below 1V - limits power dissipation in IC and external components during short-circuit. |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Powering core logic and I/O rails in sub-notebook and tablet platforms with tight space constraints and dynamic load profiles. IC Role / Device Role / Timing Role: Primary 3.3V buck converter delivering up to 4.5A with fast load-step response and minimal output ripple. Use Value: Enables use of 1.8µH inductor and compact solid tantalum output capacitor (e.g., 100µF/10V TPS), reducing board area by >30% vs legacy 300kHz regulators. | Use Scenario: Supplying microcontroller, display, and sensor subsystems in handheld medical devices and wireless sensors operating from single Li-ion cells. IC Role / Device Role / Timing Role: Main system regulator converting 4.2V–3.0V battery range to stable 3.3V with <20µA shutdown current. Use Value: Maintains regulation down to 4.0V input, extending usable battery life; shutdown mode draws only 20µA - enabling multi-week standby. |
| Battery Charger | Distributed Power |
Use Scenario: Providing regulated 3.3V auxiliary supply for charge management ICs and fuel gauges in smart battery packs. IC Role / Device Role / Timing Role: Secondary regulator deriving clean 3.3V rail from higher-voltage charging bus (e.g., 5V–12V USB PD or adapter output). Use Value: Operates across 4V–15V input range without external LDO pre-regulator; 500kHz switching avoids audible noise in sensitive audio circuits. | Use Scenario: Local point-of-load conversion in industrial IoT gateways where multiple isolated 3.3V domains are required from a shared 12V backplane. IC Role / Device Role / Timing Role: Compact, thermally robust buck stage mounted directly on module PCB near FPGA or MCU power pins. Use Value: SO-8 package with fused GND tab enables >2W continuous power delivery with standard reflow; cycle-by-cycle limiting protects against hot-swap transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3621EDD-3.3#TRMPBF | 4A synchronous buck, 3MHz switching, 2.7–5.5V input - lacks BOOST pin, uses MOSFETs instead of bipolar switch. | Optimized for ultra-compact designs with ceramic capacitors; not suitable for 4–15V wide-input or high-peak-current (>4.5A) apps. | Select LTC3621 only if input is ≤5.5V and board space is critical; LT1506CR-3.3#PBF remains preferred for wide-input, high-current, cost-sensitive designs. |
| TPS54331DR | 3A adjustable-output buck, 570kHz, 3.5–28V input - no fixed 3.3V option, requires external feedback resistors. | Supports higher input voltages but delivers lower peak current; lacks integrated BOOST and foldback protection. | Choose TPS54331 only if input exceeds 15V or adjustable output is required; LT1506CR-3.3#PBF offers superior 4.5A capability and fixed-3.3V accuracy out-of-box. |
Compared with LTC3621EDD-3.3#TRMPBF and TPS54331DR, the LT1506CR-3.3#PBF delivers higher peak current (4.5A vs 4A/3A), wider input range (4–15V vs 2.7–5.5V/3.5–28V), and factory-trimmed 3.3V output - making it optimal for battery-fed systems needing robust, plug-and-play 3.3V regulation.
Availability
LT1506CR-3.3#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-3.3#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT1506CR-3.3#PBF belongs to Linear's monolithic buck regulator product line, designed specifically for high-efficiency, wide-input DC/DC conversion in space-constrained, battery-operated equipment.
FAQ
What is the guaranteed output voltage tolerance of the LT1506CR-3.3#PBF over temperature and line/load?
The LT1506CR-3.3#PBF guarantees a fixed 3.3V output with ±1.5% tolerance across operating temperature (0°C to 125°C), input voltage (4V to 15V), and full load range - achieved via on-die trimming of the SENSE reference and direct output connection eliminating external resistor errors.
Can the LT1506CR-3.3#PBF operate from a single-cell Li-ion battery throughout its discharge curve?
Yes, the LT1506CR-3.3#PBF operates from 4.0V minimum input, covering the full useful discharge range of a single Li-ion cell (4.2V down to ~3.0V), though regulation ceases below 4.0V. Its 4V start-up threshold ensures reliable turn-on even at end-of-charge voltage.
What is the purpose of the BOOST pin on the LT1506CR-3.3#PBF and how is it implemented?
The BOOST pin on the LT1506CR-3.3#PBF supplies a boosted voltage (~VIN + 5V) to the base drive of the internal NPN power switch, enabling saturation and achieving a low 0.07Ω on-resistance. It requires an external flying capacitor and Schottky diode (e.g., MBRS330T3) connected between VIN and BOOST.
Does the LT1506CR-3.3#PBF include thermal protection, and what is its trip threshold?
Yes, the LT1506CR-3.3#PBF includes thermal shutdown protection that activates at 125°C junction temperature. Once triggered, the device halts switching until junction temperature falls below the hysteresis threshold (~115°C), preventing permanent damage during sustained overload or poor heatsinking.
How does the LT1506CR-3.3#PBF handle short-circuit conditions on its output?
The LT1506CR-3.3#PBF employs dual-foldback protection during short-circuit: (1) switch current limit reduces from 4.5A to <3A when SENSE voltage drops below 1.7V, and (2) switching frequency folds back ~5:1 when SENSE falls below 1V - jointly limiting power dissipation in the IC, catch diode, and inductor.
LT1506CR-3.3#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:
- 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:
- DDPAK-7
LT1506CR-3.3#PBF FAQ
1.How can I place an order for LT1506CR-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1506CR-3.3#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-3.3#PBF reliable?
The price and inventory of LT1506CR-3.3#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-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LT1506CR-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1506CR-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1506CR-3.3#PBF?
LT1506CR-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1506CR-3.3#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-3.3#PBF?
For technical support, including LT1506CR-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1506CR-3.3#PBF requirements.
6.How does Aetrix verify that LT1506CR-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LT1506CR-3.3#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-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LT1506CR-3.3#PBF?
All LT1506CR-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1506CR-3.3#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-3.3#PBF part is unused and in its original packaging.
Return procedure for LT1506CR-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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