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Analog Devices Inc. LT1506CR-3.3#TRPBF
- Part No.:
- LT1506CR-3.3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LT1506CR-3.3#TRPBF.pdf
- Description:
- IC REG BUCK 3.3V 4.5A DDPAK-7
- Quantity:
- Payment:
- Shipping:
Inventory:4,653
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Product details
Overview
LT1506CR-3.3#TRPBF from Analog Devices (formerly Linear Technology) is a fixed 3.3V, 4.5A monolithic 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 requiring compact, high-efficiency DC/DC conversion.
For engineers reviewing the LT1506CR-3.3#TRPBF datasheet, LT1506CR-3.3#TRPBF pinout, LT1506CR-3.3#TRPBF application, or LT1506CR-3.3#TRPBF equivalent, key selection considerations include its fixed 3.3V output, 4.5A switch rating, SO-8 thermal performance (θJA = 80°C/W), shutdown current of 20µA, and compatibility with standard surface-mount inductors down to 1.8µH.
Technical Context
The LT1506CR-3.3#TRPBF implements a current-mode buck topology with internal 500kHz oscillator, bipolar NPN power switch, and BOOST pin-driven saturation for low conduction loss. Its error amplifier drives the VC pin to set peak switch current, enabling fast transient response and stable loop compensation without external slope compensation.
It features dual shutdown thresholds (0.4V for micropower shutdown, 2.38V for UVLO), SENSE pin replacing FB for fixed 3.3V operation (3.25–3.35V tolerance), and full-cycle short-circuit protection with thermal shutdown. The SO-8 package includes fused GND pin connected to internal tab for enhanced thermal dissipation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1.5% (3.25V–3.35V) - eliminates external feedback divider, reduces BOM count and layout sensitivity. |
| Switch Current Limit | 4.5A typical at ≤50% duty cycle - supports continuous 4A output with proper inductor selection and thermal management. |
| Switch On Resistance | 0.07Ω typical at 4.5A - enables >89% efficiency at 5V→3.3V/4A, reducing heat generation vs. conventional bipolar designs. |
| Minimum Input Voltage | 4.0V - allows operation directly from single-cell Li-ion (fully charged ~4.2V) or 5V USB-supplied systems. |
| Shutdown Current | 20µA typical - extends battery life in portable applications during sleep or standby modes. |
| Switching Frequency | 500kHz ±8% - enables use of small inductors (e.g., 1.8µH) and ceramic output capacitors while maintaining EMI manageability. |
| Thermal Resistance θJA | 80°C/W (SO-8 with fused GND) - requires PCB copper area under tab for reliable 4.5A operation at ambient ≤70°C. |
Pinout & Package
LT1506CR-3.3#TRPBF uses an 8-lead plastic SO package (SO-8) with fused GND pin connected to internal thermal tab. Pin 1 is VIN; pin 2 is BOOST; pin 3 is GND (fused, tab-connected); pin 4 is VSW; pin 5 is SYNC; pin 6 is SHDN; pin 7 is VC; pin 8 is SENSE.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply collector node | Supplies internal bias and powers NPN switch collector; must be bypassed locally with low-ESR capacitor to suppress dI/dt spikes. |
| BOOST | Switch drive voltage boost | Connected via external capacitor-diode network to raise drive voltage above VIN, enabling NPN saturation and 0.07Ω RON. |
| GND | Reference and thermal return | Fused pin tied to internal tab; must connect to large copper area for thermal relief and low-impedance ground reference. |
| VSW | Switch emitter node | Drives inductor; swings negative during off-time - requires catch diode clamped to ≥–0.8V. |
| SYNC | Oscillator synchronization input | Logic-compatible input (10–90% duty) to synchronize internal 500kHz oscillator up to 1MHz; grounded when unused. |
| SHDN | Enable/disable control | Active-low logic input: <0.37V enables shutdown (20µA IQ); >2.38V enables UVLO lockout before startup. |
| VC | Error amplifier output / current limit control | Directly sets peak switch current; used for compensation, current clamping, or loop override - floats between ~1V–2V under load. |
| SENSE | Fixed-output voltage sense | Replaces FB pin on -3.3 variants; connects directly to 3.3V output to close regulation loop with internal 2.42V reference. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode control | Enables inherent cycle-by-cycle current limiting and stable loop compensation without external slope compensation components. |
| BOOST-pin saturation drive | Reduces switch conduction loss to FET-equivalent level (0.07Ω), achieving >89% efficiency at 5V→3.3V/4A. |
| Dual-threshold shutdown | Separate 0.4V (micropower) and 2.38V (UVLO) thresholds allow precise input voltage sequencing and battery low-voltage cutoff. |
| Frequency foldback protection | Automatically reduces switching frequency and peak current when output collapses (<1V on SENSE), limiting power dissipation during short-circuit faults. |
| SO-8 fused-GND thermal design | Tab-connected GND pin enables direct thermal coupling to PCB copper, supporting 4.5A operation with θJA = 80°C/W. |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Core voltage regulation for embedded microcontrollers and peripherals in clamshell notebooks with space-constrained layouts. IC Role / Device Role / Timing Role: Primary 3.3V buck converter delivering up to 4A from 5V or single-cell Li-ion input, operating down to 4.0V input. Use Value: Enables compact design using 1.8µH inductor and solid tantalum output capacitor, with 20µA shutdown current extending runtime in suspend mode. | Use Scenario: Power management in handheld test equipment powered by rechargeable Li-ion packs. IC Role / Device Role / Timing Role: Fixed 3.3V step-down regulator supplying analog front-end, ADC, and wireless transceiver subsystems. Use Value: Stable 3.3V output across 4–15V input range ensures consistent sensor readings and RF performance during battery discharge. |
| Battery Charger | Distributed Power |
Use Scenario: Auxiliary 3.3V rail generation in multi-bay smart chargers powering MCU, display, and communication ICs. IC Role / Device Role / Timing Role: Secondary regulator fed from main charger's 5V bus, providing isolated low-noise supply for digital control logic. Use Value: Integrated current limiting and thermal shutdown prevent fault propagation during cell insertion/removal events. | Use Scenario: Local point-of-load conversion in industrial IoT gateways with distributed 5V/12V backplanes. IC Role / Device Role / Timing Role: Compact 3.3V buck stage converting 5V backplane to processor core voltage, synchronized to system clock via SYNC pin. Use Value: 500kHz fixed frequency with SYNC capability minimizes conducted EMI overlap with sensitive RF bands in dense board layouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EDE-3.3#TRPBF | 4A synchronous buck, 3MHz switching, integrated MOSFETs, 2.5V–5.5V input, no BOOST pin required | Higher efficiency at light loads due to synchronous rectification; smaller solution size but higher cost and lower max current | Select for ultra-compact designs where 4A is sufficient and 3MHz operation avoids AM band interference. |
| TPS54331DR | 3A adjustable-output buck, 570kHz, integrated FETs, 3.5V–28V input, no BOOST pin, different pinout | Wider input range and adjustable output, but lower current rating and no fixed 3.3V variant with identical SO-8 footprint | Select when input exceeds 15V or output adjustability is needed; not drop-in compatible due to pinout and current limit mismatch. |
Compared with LTC3605EDE-3.3#TRPBF and TPS54331DR, the LT1506CR-3.3#TRPBF delivers higher peak current (4.5A vs. 4A/3A), supports lower input voltage (4V vs. 2.5V/3.5V), and retains BOOST-based bipolar saturation for robustness in high-temperature environments - making it preferred for 4–15V battery-fed systems demanding proven reliability over 20+ years.
Availability
LT1506CR-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-lifecycle support, and traceable sourcing.
Supply support for LT1506CR-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 support for legacy Linear power products. Linear was renowned for high-performance analog and power management ICs with rigorous characterization and long-term availability.
The LT1506 product line was designed specifically for low-input-voltage, high-current buck conversion in space-constrained portable and battery-operated equipment - emphasizing thermal robustness, wide input range (4V–15V), and integrated protection features.
FAQ
What is the maximum continuous output current of the LT1506CR-3.3#TRPBF?
The LT1506CR-3.3#TRPBF supports up to 4A continuous output current under typical conditions (VIN = 5V, VOUT = 3.3V, L = 5µH, ambient ≤70°C, SO-8 with adequate copper). Its 4.5A internal switch current limit decreases with duty cycle - e.g., to ~3.7A at 80% duty - and actual load current depends on inductor value, input voltage, and thermal design. Derating is required above 70°C ambient.
Does the LT1506CR-3.3#TRPBF require an external BOOST capacitor?
Yes, the LT1506CR-3.3#TRPBF requires an external BOOST capacitor (typically 10nF–100nF ceramic) connected between BOOST and VIN pins via a Schottky diode (e.g., MBRS330T3). This network generates a voltage higher than VIN to saturate the internal bipolar NPN switch, achieving the specified 0.07Ω on-resistance and >89% efficiency. Omitting it degrades efficiency and increases thermal stress.
Can the LT1506CR-3.3#TRPBF be synchronized to an external clock?
Yes, the LT1506CR-3.3#TRPBF includes a dedicated SYNC pin (pin 5) that accepts logic-level signals (10–90% duty cycle) to synchronize its internal 500kHz oscillator across a 580kHz–1MHz range. When unused, SYNC must be grounded. This feature enables EMI reduction in noise-sensitive systems and timing alignment with other switching regulators on the same board.
What is the purpose of the SENSE pin on the LT1506CR-3.3#TRPBF?
The SENSE pin on the LT1506CR-3.3#TRPBF replaces the FB pin found on adjustable versions and connects directly to the 3.3V output. It closes the regulation loop using an internal 2.42V reference and fixed resistor divider, eliminating external feedback components. Its voltage tolerance is 3.25V–3.35V (±1.5%), and it enables foldback protection - reducing frequency and current limit if output collapses below ~1V.
How does thermal management work for the LT1506CR-3.3#TRPBF in SO-8 package?
The LT1506CR-3.3#TRPBF SO-8 package features a fused GND pin (pin 3) directly bonded to the internal thermal tab. To achieve the specified θJA = 80°C/W, this pin must be soldered to a minimum 0.5 square inch copper area on the PCB's inner or outer layer, preferably connected to a ground plane. Without this, junction temperature rise exceeds safe limits at >2A loads, triggering thermal shutdown.
LT1506CR-3.3#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- 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:
- DDPAK-7
LT1506CR-3.3#TRPBF FAQ
1.How can I place an order for LT1506CR-3.3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1506CR-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 LT1506CR-3.3#TRPBF reliable?
The price and inventory of LT1506CR-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 LT1506CR-3.3#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1506CR-3.3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1506CR-3.3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1506CR-3.3#TRPBF?
LT1506CR-3.3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1506CR-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 LT1506CR-3.3#TRPBF?
For technical support, including LT1506CR-3.3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1506CR-3.3#TRPBF requirements.
6.How does Aetrix verify that LT1506CR-3.3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1506CR-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 LT1506CR-3.3#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1506CR-3.3#TRPBF?
All LT1506CR-3.3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1506CR-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 LT1506CR-3.3#TRPBF part is unused and in its original packaging.
Return procedure for LT1506CR-3.3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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