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Analog Devices Inc. LT1269CT#PBF
- Part No.:
- LT1269CT#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-220-5
- Datasheet:
-
LT1269CT#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 4A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,528
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Product details
Overview
LT1269CT#PBF from Analog Devices (formerly Linear Technology) is a monolithic 100kHz, 4A high-efficiency switching regulator in a 5-lead TO-220 package, featuring internal power switch, current-mode control, and flyback-regulated floating outputs. It operates from 3.5V to 30V input, delivers up to ~3.5A at 5V in buck mode, and supports boost, buck-boost, and inverting topologies for PC power supplies, battery up-converters, and negative-to-positive converters.
For engineers reviewing the LT1269CT#PBF datasheet, LT1269CT#PBF pinout, LT1269CT#PBF application, or LT1269CT#PBF equivalent, key selection criteria include its 100kHz switching frequency, 4A internal switch, 7mA quiescent current, shutdown threshold of 100µA, and compatibility with standard TO-220 thermal management in high-power DC/DC designs.
Technical Context
The LT1269CT#PBF implements current-mode switching control with adaptive anti-saturation gate drive for wide load-current efficiency stability. Its error amplifier features 1.244V reference voltage (±20mV), 4400µmho transconductance, and clamped output (0.25–2.3V) to ensure robust feedback loop response across line and load transients.
It integrates oscillator, PWM comparator, protection circuitry, and a 0.33Ω typical RDS(on) 4A N-channel power switch. Flyback operation uses a dedicated 16.3V reference (±1.3V) with 6.8V change over 0.05–1mA FB current, enabling fully floating secondary-side regulation without optocouplers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 100kHz typical - enables compact magnetics and predictable EMI filtering with minimal core loss in 100–500kHz band |
| Internal Switch Current Limit | 4A minimum at 50% duty cycle - supports ≥3.5A continuous output in buck configuration with margin |
| Reference Voltage | 1.244V ±20mV - sets precise output voltage via external resistor divider; stable over temperature and line |
| Quiescent Current | 7mA typical - minimizes no-load power loss in always-on systems like industrial controllers |
| Shutdown Supply Current | 100µA typical - enables ultra-low standby power for battery-backed applications |
| Input Voltage Range | 3.5V to 30V - accommodates 5V/12V/24V rails and wide automotive or industrial input variations |
| Max Switch Breakdown Voltage | 60V - allows safe operation with 48V transient spikes and flyback reset margin |
Pinout & Package
LT1269CT#PBF is housed in a 5-lead plastic TO-220 package with exposed tab (θJA = 50°C/W, θJC = 4°C/W), optimized for conduction cooling via heatsink mounting. The tab is electrically connected to the GND pin.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power Input | Connects to unregulated DC source (3.5–30V); decoupling capacitor required near pin |
| VSW | Switch Output | Drives external inductor/diode; connects to drain of internal 4A N-channel MOSFET |
| GND | Power & Signal Ground | Common return for VIN, VSW, FB, VC; tab connection point for thermal and electrical grounding |
| FB | Feedback Input | Senses output voltage via resistor divider; regulates to 1.244V reference; clamp limits to 0.25–2.3V |
| VC | Control Voltage | Accepts error amplifier output; controls duty cycle; <0.3V disables switch (shutdown mode) |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 4A Power Switch | Eliminates external MOSFET and driver, reducing BOM count and layout complexity in 3–5A DC/DC designs |
| Flyback-Regulated Floating Outputs | Enables isolated multi-output supplies without optocouplers or secondary-side regulators using 16.3V FB reference |
| Current-Mode Control | Provides inherent cycle-by-cycle current limiting, fast transient response, and stable operation with wide input/output ranges |
| Adaptive Anti-Saturation Drive | Maintains high efficiency (>90%) from light load to full 4A by dynamically optimizing gate drive timing |
| Shutdown Mode with 100µA IQ | Supports low-power sleep states in portable or energy-sensitive systems without auxiliary LDOs |
Applications
| PC Power Supply with Multiple Outputs | Battery Up-Converter |
|---|---|
Use Scenario: Generating +5V, +12V, and –12V rails from a single 24V input in desktop or embedded computing platforms. IC Role / Device Role / Timing Role: Primary controller in flyback topology; regulates multiple isolated windings using FB pin sensing and internal 100kHz oscillator. Use Value: Achieves >90% efficiency at 0.4–1.5A per rail while eliminating optocouplers and secondary-side references. | Use Scenario: Boosting 3.7V Li-ion battery voltage to 5V/9V/12V for USB peripherals or sensors in portable instrumentation. IC Role / Device Role / Timing Role: Boost converter controller with internal 4A switch; configured for fixed-frequency 100kHz operation to minimize inductor size. Use Value: Delivers up to 3A at 5V from single-cell input with only 7mA quiescent current, extending battery runtime. |
| Negative-to-Positive Converter | High Efficiency Buck Converter |
Use Scenario: Converting –12V supply to +5V for analog front-end circuits in telecom line cards or test equipment. IC Role / Device Role / Timing Role: Inverting buck-boost controller; uses VSW and GND pins to invert polarity while regulating output via FB feedback. Use Value: Provides regulated +5V at 1.5A with no external P-channel switch or level-shifting circuitry. | Use Scenario: Stepping down 24V industrial bus to 5V/3.3V for microcontrollers and I/O in factory automation modules. IC Role / Device Role / Timing Role: Synchronous-capable buck controller; drives external diode or synchronous rectifier; 100kHz frequency balances efficiency and EMI. Use Value: Supports 3.5A output with <0.33Ω RDS(on), enabling >88% efficiency at full load without forced air cooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-current switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1374CS8#PBF | 500kHz, 4.5A buck-only regulator in SO-8; no flyback/inverting support; higher frequency enables smaller inductors | Optimized for space-constrained buck-only designs; lacks multi-topology flexibility of LT1269CT#PBF | Select when board area is critical and only buck conversion is needed; avoid if flyback or inverting topologies are required |
| LT1171CT#PBF | 100kHz, 2.5A regulator in TO-220; same topology support but lower current rating and 40V max input | Suitable for ≤2A outputs; less thermal headroom than LT1269CT#PBF in high-ambient environments | Choose for cost-sensitive 2A designs where 4A capability is unnecessary; verify thermal derating at 100°C ambient |
Compared with LT1374CS8#PBF and LT1171CT#PBF, the LT1269CT#PBF uniquely combines 4A current capability, 100kHz operation, and full topology support (buck, boost, flyback, inverting) in a thermally robust TO-220 package-making it optimal for multi-rail industrial power supplies requiring design flexibility and field-proven reliability.
Availability
LT1269CT#PBF is available at Aetrix Electronics and suitable for PC power supplies, battery-powered up-converters, and industrial buck converters requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LT1269CT#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 power management portfolio with rigorous qualification and long-term product support.
The LT1269CT#PBF belongs to Linear's monolithic switching regulator family designed for rugged, high-current DC/DC conversion in industrial, telecom, and computing applications where thermal performance and topology flexibility are critical.
FAQ
What is the maximum output current achievable with the LT1269CT#PBF in buck configuration?
The LT1269CT#PBF supports up to approximately 3.5A continuous output current in buck mode, derived from its 4A minimum switch current limit and thermal limits of the TO-220 package (θJA = 50°C/W). At 25°C ambient with adequate heatsinking, sustained 3A operation is reliably achievable with >85% efficiency. Higher currents require careful thermal design and derating above 70°C ambient.
Does the LT1269CT#PBF support synchronization to an external clock?
No, the LT1269CT#PBF does not support external clock synchronization. Unlike some later-generation regulators, it uses an internal free-running oscillator set to 100kHz. The datasheet notes that external sync capability is available in the LT1072, but this feature is not implemented in the LT1269CT#PBF. Designers requiring synchronized switching must use alternative parts such as the LT3751 or LTC3891.
Can the LT1269CT#PBF be used in flyback topology with primary-side regulation only?
Yes, the LT1269CT#PBF supports primary-side regulated flyback operation using its dedicated flyback reference voltage of 16.3V (±1.3V) on the FB pin. This allows regulation of isolated secondary outputs without optocouplers or TL431-based feedback networks. The internal 16.3V reference and 6.8V change over FB current range enable accurate sensing of reflected flyback voltage across the transformer auxiliary winding.
What is the purpose of the VC pin on the LT1269CT#PBF, and how is it used in shutdown mode?
The VC pin on the LT1269CT#PBF is the error amplifier output and duty cycle control node. When pulled below 0.3V (typically via external transistor or logic signal), it forces the internal switch into shutdown, reducing total supply current to 100µA typical. In normal operation, VC floats between 0.8V and 1.4V to regulate output; its clamping range (0.25–2.3V) prevents loop instability during transients.
Is the LT1269CT#PBF RoHS compliant and lead-free?
Yes, the LT1269CT#PBF is RoHS compliant and lead-free. The "#PBF" suffix explicitly denotes Pb-free (lead-free) packaging per JEDEC J-STD-609, with NiPdAu lead finish and halogen-free molding compound. It meets EU RoHS Directive 2011/65/EU and Analog Devices' environmental specifications for industrial-grade products.
LT1269CT#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-220-5
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost, Buck-Boost, Flyback
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.5V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 1.244V
- Voltage - Output (Max):
- 60V (Switch)
- Current - Output:
- 4A (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 100°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
LT1269CT#PBF FAQ
1.How can I place an order for LT1269CT#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1269CT#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 LT1269CT#PBF reliable?
The price and inventory of LT1269CT#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1269CT#PBF is usually 5 days.
3.What payment methods are accepted for LT1269CT#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1269CT#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1269CT#PBF?
LT1269CT#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1269CT#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 LT1269CT#PBF?
For technical support, including LT1269CT#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1269CT#PBF requirements.
6.How does Aetrix verify that LT1269CT#PBF is sourced from the original manufacturer or authorized distributors?
All LT1269CT#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 LT1269CT#PBF meets industry standards.
7.What is the process for return or replacement of LT1269CT#PBF?
All LT1269CT#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1269CT#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 LT1269CT#PBF part is unused and in its original packaging.
Return procedure for LT1269CT#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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