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Analog Devices Inc. LT1506CR-3.3SYNC#PBF
- Part No.:
- LT1506CR-3.3SYNC#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LT1506CR-3.3SYNC#PBF.pdf
- Description:
- IC REG BUCK 3.3V 4.5A DDPAK-7
- Quantity:
- Payment:
- Shipping:
Inventory:1,221
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Product details
Overview
LT1506CR-3.3SYNC#PBF from Analog Devices (formerly Linear Technology) is a 4.5A, 500kHz fixed-output synchronous buck switching regulator in SO-8 package with integrated 0.07Ω NPN power switch, 3.3V output, and SYNC pin for external oscillator synchronization up to 1MHz. It operates from 4V–15V input, delivers up to 4A continuous load, and targets portable computers and battery-powered systems requiring compact, efficient DC/DC conversion.
For engineers reviewing the LT1506CR-3.3SYNC#PBF datasheet, LT1506CR-3.3SYNC#PBF pinout, LT1506CR-3.3SYNC#PBF application, or LT1506CR-3.3SYNC#PBF equivalent, key selection considerations include its fixed 3.3V SENSE-pin architecture, 500kHz base frequency with 580kHz–1MHz sync range, 20µA shutdown current, 4.5A switch current limit, and thermal shutdown with cycle-by-cycle current limiting.
Technical Context
The LT1506CR-3.3SYNC#PBF implements constant-frequency current-mode control using an internal 500kHz oscillator and peak-current sensing via the SENSE pin. Its bipolar NPN switch is driven by a BOOST capacitor to achieve saturation and low on-resistance (0.07Ω), enabling >89% efficiency at 5V→3.3V conversion.
Synchronization is achieved through logic-level compatible SYNC pin (1.5–2.2V threshold), replacing SHDN functionality in this variant. The device features foldback current limiting and frequency reduction below 1V SENSE voltage, plus dual-threshold shutdown (0.4V full micropower, 2.38V UVLO lockout).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1.5% (3.25–3.35V), sensed directly at SENSE pin for precision regulation without external divider. |
| Switch Current Limit | 4.5A typical (min 4.5A, max 8.5A), cycle-by-cycle protected; derates nonlinearly above 50% duty cycle per slope compensation. |
| Switching Frequency | 500kHz nominal (460–540kHz), synchronizable from 580kHz to 1MHz via external logic signal on SYNC pin. |
| Input Voltage Range | 4.0V to 15V minimum-to-maximum; supports 4V startup with regulated bias under light loads. |
| Shutdown Current | 20µA typical (15–50µA), achieved when SYNC pin is held low (0V), enabling ultra-low-power standby mode. |
| On-Resistance | 0.07Ω typical (0.1Ω max) at 4.5A, enabled by BOOST pin drive; reduces conduction loss and improves thermal performance. |
| Thermal Protection | Internal thermal shutdown activates at junction temperature ≥125°C; SO-8 package θJA = 80°C/W with fused GND tab. |
Pinout & Package
LT1506CR-3.3SYNC#PBF uses an 8-lead plastic SOIC (SO-8) package with fused GND pin attached to internal tab for enhanced thermal dissipation. Pin 1 is VIN, Pin 2 is BOOST, Pin 3 is GND (fused), Pin 4 is VSW, Pin 5 is SYNC, Pin 6 is VC, Pin 7 is SENSE, Pin 8 is NC (no connect).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Input supply and collector of internal NPN switch | Must be bypassed near pin with low-ESR capacitor; high dI/dt edges require short PCB traces to minimize voltage spikes. |
| BOOST (Pin 2) | Boost capacitor drive node | Provides voltage >VIN to saturate NPN switch; requires external 1.5nF capacitor and Schottky diode (e.g., MBRS330T3). |
| GND (Pin 3) | Power and signal reference ground | Fused to internal tab; must connect to large copper area for thermal management and low-impedance return path. |
| VSW (Pin 4) | Emitter of internal NPN switch | Drives inductor; swings negative during off-time-requires external catch diode clamped to −0.8V max. |
| SYNC (Pin 5) | External oscillator synchronization input | Logic-compatible (10–90% duty cycle); enables precise frequency alignment across multiple regulators in distributed systems. |
| VC (Pin 6) | Error amplifier output / current comparator input | Used for loop compensation; also serves as current clamp point-driving it to ground disables switching. |
| SENSE (Pin 7) | Fixed 3.3V output feedback node | Replaces FB pin in -3.3 variants; connects directly to output for accurate regulation without external resistors. |
| NC (Pin 8) | No connect | Not internally bonded; left unconnected per datasheet; no routing or termination required. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 4.5A NPN power switch | Eliminates need for external MOSFET and gate driver; reduces BOM count and layout complexity in space-constrained designs. |
| BOOST-driven saturation | Enables 0.07Ω on-resistance using bipolar process-achieving FET-like efficiency with smaller die area and lower cost. |
| Current-mode control architecture | Delivers fast transient response and inherent stability without complex compensation; supports wide input/output ratios. |
| Frequency and current foldback | Reduces switching frequency and peak current during overload/short-circuit, limiting power dissipation in IC and external components. |
| Thermal shutdown + cycle-by-cycle protection | Prevents damage under sustained overloads or ambient overheating; ensures robust operation in unventilated enclosures. |
Applications
| Portable Computers | Battery-Powered Systems |
|---|---|
Use Scenario: Core voltage regulation for low-power microcontrollers and peripherals in clamshell notebooks and tablets. IC Role / Device Role / Timing Role: Primary 3.3V buck converter supplying SoC I/O rails and USB PHYs with tight load-transient response. Use Value: 4.5A capability and 500kHz switching enable compact 1.8µH inductor use; BOOST architecture sustains >89% efficiency at 5V→3.3V conversion. | Use Scenario: Power management in handheld medical monitors, barcode scanners, and wireless sensors operating from single Li-ion cells. IC Role / Device Role / Timing Role: Main system regulator delivering stable 3.3V from 4–15V battery packs or adapters, with shutdown for sleep-mode current reduction. Use Value: 20µA shutdown current extends battery life; 4V minimum input supports operation down to nearly depleted cells. |
| Battery Charger | Distributed Power |
Use Scenario: Auxiliary 3.3V rail generation in multi-cell Li-ion charger ICs for status LEDs, communication interfaces, and MCU supervision. IC Role / Device Role / Timing Role: Secondary regulator isolated from main charging path, providing clean, ripple-free supply for analog and digital monitoring circuitry. Use Value: Fixed SENSE-pin topology eliminates resistor tolerance errors; current-mode control rejects input ripple from noisy AC/DC adapters. | Use Scenario: Local point-of-load conversion in telecom line cards, industrial PLCs, and modular instrumentation where multiple synchronized rails are required. IC Role / Device Role / Timing Role: Synchronized buck stage slaved to system clock to eliminate beat frequencies and reduce EMI in dense PCB layouts. Use Value: SYNC pin allows deterministic 580kHz–1MHz alignment across multiple LT1506CR-3.3SYNC#PBF units-reducing conducted noise peaks by >10dB. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EDE-3.3#PBF | 4A monolithic buck with 3MHz switching, integrated MOSFETs, and ±1% output accuracy; no BOOST pin or SYNC capability. | Higher frequency enables smaller passive components but lacks synchronization and bipolar efficiency at high current. | Choose LTC3605EDE-3.3#PBF for ultra-compact designs needing <1µH inductors; avoid if system-level sync or >4A peak load is required. |
| TPS54331DR | 3A adjustable buck with 570kHz–750kHz frequency, external COMP pin, and 4.5–28V input; no fixed 3.3V option or BOOST architecture. | Requires external feedback resistors; lower current rating limits use in high-power portable applications. | Choose TPS54331DR for cost-sensitive, non-synchronized 3A designs with wider input range; not drop-in for LT1506CR-3.3SYNC#PBF's 4.5A/3.3V/SYNC requirements. |
Compared with LTC3605EDE-3.3#PBF and TPS54331DR, the LT1506CR-3.3SYNC#PBF uniquely combines 4.5A current capability, fixed 3.3V SENSE-pin accuracy, BOOST-enabled bipolar efficiency, and hardware SYNC-making it optimal for legacy or noise-sensitive 500kHz-synchronized systems where thermal headroom and simplicity are critical.
Availability
LT1506CR-3.3SYNC#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-3.3SYNC#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, serving industrial, automotive, communications, and healthcare markets.
The LT1506 product line was designed as a high-efficiency, low-input-voltage buck regulator family optimized for 4V–15V inputs and portable computing applications-emphasizing thermal robustness, synchronization capability, and integration of bipolar power switches with BOOST drive.
FAQ
What is the minimum input voltage required for LT1506CR-3.3SYNC#PBF to regulate 3.3V output?
The LT1506CR-3.3SYNC#PBF guarantees operation down to 4.0V input (typical 4.3V) while maintaining 3.3V regulation. Below this, internal bias lines lose regulation, causing oscillator frequency drift and reference voltage instability. Actual minimum depends on load current and output voltage-e.g., at 4A load and 3.3V out, 4.2V input is recommended per Typical Performance Characteristics graph G12.
Can LT1506CR-3.3SYNC#PBF be used without the BOOST capacitor?
No-LT1506CR-3.3SYNC#PBF requires the external BOOST capacitor (1.5nF) and Schottky diode (e.g., MBRS330T3) to saturate the internal NPN switch. Omitting it increases on-resistance from 0.07Ω to ~0.13Ω, degrading efficiency by ~5–7% and raising junction temperature significantly under 4A loads.
What is the function of the SENSE pin on LT1506CR-3.3SYNC#PBF?
The SENSE pin on LT1506CR-3.3SYNC#PBF replaces the FB pin in adjustable variants and connects directly to the 3.3V output to close the regulation loop. It senses output voltage with ±0.5% accuracy (3.25–3.35V), eliminating external resistors and associated tolerance errors-critical for precision I/O rail applications.
Does LT1506CR-3.3SYNC#PBF support forced PWM or discontinuous conduction mode?
LT1506CR-3.3SYNC#PBF operates exclusively in forced continuous conduction mode (CCM) due to its constant-frequency current-mode architecture. It does not enter discontinuous mode (DCM) even at light loads-the error amplifier maintains minimum VC voltage (~1V) to sustain switching, ensuring predictable EMI and transient behavior.
How does the SYNC pin affect the shutdown functionality of LT1506CR-3.3SYNC#PBF?
The LT1506CR-3.3SYNC#PBF replaces the SHDN pin with SYNC-so it has no dedicated shutdown control. To disable regulation, drive the VC pin to ground (via open-collector transistor or logic gate), which forces the current comparator inactive. This achieves full shutdown with <1µA quiescent current, distinct from the 20µA standby state when SYNC is low.
LT1506CR-3.3SYNC#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-3.3SYNC#PBF FAQ
1.How can I place an order for LT1506CR-3.3SYNC#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1506CR-3.3SYNC#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-3.3SYNC#PBF reliable?
The price and inventory of LT1506CR-3.3SYNC#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-3.3SYNC#PBF is usually 5 days.
3.What payment methods are accepted for LT1506CR-3.3SYNC#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1506CR-3.3SYNC#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1506CR-3.3SYNC#PBF?
LT1506CR-3.3SYNC#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1506CR-3.3SYNC#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-3.3SYNC#PBF?
For technical support, including LT1506CR-3.3SYNC#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1506CR-3.3SYNC#PBF requirements.
6.How does Aetrix verify that LT1506CR-3.3SYNC#PBF is sourced from the original manufacturer or authorized distributors?
All LT1506CR-3.3SYNC#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-3.3SYNC#PBF meets industry standards.
7.What is the process for return or replacement of LT1506CR-3.3SYNC#PBF?
All LT1506CR-3.3SYNC#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1506CR-3.3SYNC#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-3.3SYNC#PBF part is unused and in its original packaging.
Return procedure for LT1506CR-3.3SYNC#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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