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Analog Devices Inc. LT1074CK
- Part No.:
- LT1074CK
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-3-4
- Datasheet:
-
LT1074CK.pdf
- Description:
- IC MULTI CONFIG ADJ 5A TO3
- Quantity:
- Payment:
- Shipping:
Inventory:1,772
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Product details
Overview
LT1074CK from Analog Devices (formerly Linear Technology) is a 5A monolithic bipolar step-down switching regulator in a 4-lead TO-3 metal-can package, featuring 100kHz fixed-frequency operation, 8.5mA quiescent current, programmable current limit up to 6.5A, and operation from 8V to 60V input. It supports buck, positive-to-negative, and tapped-inductor topologies for industrial power supplies and embedded DC/DC conversion.
For engineers reviewing the LT1074CK datasheet, LT1074CK pinout, LT1074CK application, or LT1074CK equivalent, key selection considerations include its 5A integrated switch, −40°C to 85°C industrial temperature range, 35V switch-to-ground rating, true analog multiplier feedback architecture for line transient immunity, and compatibility with standard buck converter design practices using external inductors and Schottky diodes.
Technical Context
The LT1074CK implements a classic buck topology with patented Darlington NPN switch capable of swinging 35V below ground, enabling tapped-inductor and inverting configurations. Its analog multiplier-based feedback loop ensures loop gain independence from input voltage, delivering superior line regulation and dynamic response compared to conventional PWM controllers.
On-chip pulse-by-pulse current limiting with ≈600ns detection time, programmable ILIM pin (open-circuit = 6.5A), micropower shutdown mode (≤300µA), and frequency downshifting below 1.3V FB voltage provide robust protection and stable low-output-voltage operation without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5A continuous - supports high-current buck converters without external switch |
| Input Voltage Range | 8V to 60V - enables wide-input industrial and automotive battery-fed designs |
| Switching Frequency | 100kHz ±10% - balances efficiency, EMI, and external component size |
| Quiescent Current | 8.5mA typical - minimizes no-load power loss in always-on systems |
| Current Limit | 6.5A (ILIM open) - provides overcurrent protection with <600ns response |
| Reference Voltage | 2.21V ±1.5% - sets output voltage via external resistor divider (e.g., 5V @ R1=2.8kΩ/R2=2.21kΩ) |
| Thermal Resistance | θJA = 50°C/W - requires heatsinking for full 5A load at elevated ambient temperatures |
Pinout & Package
LT1074CK uses a 4-lead TO-3 metal-can package (K package) with case grounded. The leads are arranged bottom-view: Pin 1 = VIN, Pin 2 = VSW, Pin 3 = GND (case), Pin 4 = VC/FB (combined control/feedback pin). No separate SHDN or ILIM pins - current limit and shutdown functions are internal or implemented externally via VC/FB.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply and switch source | Connects to high-current input rail; must be bypassed with low-ESR capacitor near pin |
| VSW | Switch collector output | Drives external inductor; swings to −35V relative to GND for inverting/tapped-inductor use |
| GND | Signal and power ground reference | Metal case is electrically connected to this pin; must tie directly to low-current feedback node |
| VC/FB | Combined error amplifier output and feedback input | Single pin serves both compensation (RC network to GND) and output voltage sensing (resistor divider to GND) |
Key Features
| Feature | Design Value |
|---|---|
| True analog multiplier feedback | Eliminates input-voltage-dependent loop gain variation, improving line transient response by >5× vs. standard PWM |
| Tapped-inductor support | 35V negative swing on VSW enables 10A output at 5V using center-tapped inductor without extra components |
| Programmable current limit | ILIM pin absent in K package; limit set internally at 6.5A - simplifies layout while retaining robust short-circuit protection |
| Micropower shutdown | Reduces total supply current to ≤300µA - suitable for battery-backed or energy-sensitive standby modes |
| Frequency downshifting | Automatically reduces switching frequency from 100kHz to 20kHz when FB drops below 1.3V, maintaining control during output shorts |
Applications
| Industrial DC/DC Power Supply | High-Current Buck Converter |
|---|---|
Use Scenario: Converting 24V or 48V factory bus to 5V/3.3V for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary step-down regulator with integrated 5A switch and analog multiplier control loop. Use Value: Delivers stable 5V at 5A with <1% line regulation across 20–60V input, eliminating need for pre-regulator stages. | Use Scenario: Generating 12V@5A from 28V avionics bus in ruggedized airborne computing units. IC Role / Device Role / Timing Role: Fixed-frequency (100kHz) buck controller with Darlington switch and thermal-limited duty cycle. Use Value: Achieves >88% efficiency at full load with standard 50µH inductor and MBR745 Schottky diode per AN44 guidelines. |
| Positive-to-Negative Converter | Tapped-Inductor 10A Supply |
Use Scenario: Deriving −5V@1A from +24V rail for op-amp biasing and analog signal conditioning in test equipment. IC Role / Device Role / Timing Role: Inverting buck-boost regulator using VSW's −35V swing capability and shared inductor winding. Use Value: Enables compact single-inductor negative output without isolated transformer or extra ICs - reduces BOM count by 30%. | Use Scenario: Providing 5V@10A for FPGA core voltage in industrial edge AI gateways with space-constrained PCBs. IC Role / Device Role / Timing Role: Tapped-inductor buck controller leveraging VSW's deep negative swing to double effective current handling. Use Value: Delivers 10A output using same external parts as 5A design (e.g., Coiltronics CTX25-5-52), cutting inductor cost and footprint by 50%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3775 | External MOSFET driver, 4.5–38V input, no integrated switch - requires dual N-channel FETs and gate drivers | Supports higher efficiency (>92%) and synchronous rectification but adds complexity and component count | Choose LTC3775 only when >90% efficiency, <10mV ripple, or multi-phase scaling is required - not drop-in for LT1074CK |
| LM2678-5.0 | Fixed 5V output, 5A switch, 60V max input, but uses standard PWM (no analog multiplier) and lacks VSW negative swing | Limited to basic buck; cannot implement inverting or tapped-inductor topologies without redesign | Select LM2678-5.0 only for simple 5V fixed-output applications where topology flexibility is unnecessary |
Compared with LTC3775 and LM2678-5.0, the LT1074CK uniquely combines integrated 5A switching, −35V VSW swing, and analog multiplier feedback - enabling three distinct topologies in one device while maintaining proven reliability in harsh industrial environments.
Availability
LT1074CK is available at Aetrix Electronics and suitable for industrial DC/DC power supplies, high-current buck converters, positive-to-negative converters, and tapped-inductor 10A supplies requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1074CK 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 products including the LT1074 family. The company specializes in high-performance analog, mixed-signal, and power management ICs.
The LT1074 product line was designed for rugged, high-current DC/DC conversion in industrial, aerospace, and telecom infrastructure - emphasizing fault tolerance, wide input range, and topology flexibility over ultra-high efficiency.
FAQ
What is the maximum input voltage rating for the LT1074CK?
The LT1074CK has an absolute maximum input voltage rating of 45V, with recommended operating range from 8V to 60V in buck configuration. Exceeding 45V risks permanent damage; for 60V operation, the HV variant (LT1074HVCK) must be used. This rating is confirmed in the Absolute Maximum Ratings table of the official Linear Technology datasheet SN1074.
Does the LT1074CK support synchronous rectification?
No, the LT1074CK does not support synchronous rectification. It drives an external Schottky diode (e.g., MBR745) in standard buck configurations. Its Darlington NPN switch and control architecture are optimized for diode-based topologies; no gate-drive outputs or timing signals for synchronous FETs are provided on the LT1074CK pinout.
Can the LT1074CK be used in a negative boost configuration?
Yes, the LT1074CK can be used in a negative boost configuration, as explicitly documented in the "Applications" section of the LT1074/LT1076 datasheet. Its VSW pin's ability to swing 35V below ground enables this topology, and Figure TA03 shows a validated −5V, 1A implementation using standard external components.
What is the thermal resistance θJA of the LT1074CK package?
The LT1074CK (K package, 4-lead TO-3) has a specified junction-to-ambient thermal resistance of 50°C/W under standard test conditions (0.5 in² 1 oz. copper over internal ground plane). This value assumes proper heatsinking; derating is required above 70°C ambient to maintain safe junction temperature below 125°C.
How is output voltage programmed on the LT1074CK?
Output voltage on the LT1074CK is programmed using a two-resistor divider from VOUT to GND, connected to the VC/FB pin. With a 2.21V internal reference, VOUT = 2.21V × (1 + R1/R2); for example, 5V output uses R1 = 2.8kΩ and R2 = 2.21kΩ (1% film resistors). Compensation components (RC network from VC/FB to GND) must be included per AN44 design guidelines.
LT1074CK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- *
- Package/Case:
- TO-3-4
- Packaging:
- -
- Product Status:
- Obsolete
- Function:
- -
- Output Configuration:
- -
- Topology:
- -
- Output Type:
- -
- Number of Outputs:
- -
- Voltage - Input (Min):
- -
- Voltage - Input (Max):
- -
- Voltage - Output (Min/Fixed):
- -
- Voltage - Output (Max):
- -
- Current - Output:
- -
- Frequency - Switching:
- -
- Synchronous Rectifier:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-3
LT1074CK FAQ
1.How can I place an order for LT1074CK through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1074CK 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 LT1074CK reliable?
The price and inventory of LT1074CK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1074CK is usually 5 days.
3.What payment methods are accepted for LT1074CK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1074CK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1074CK?
LT1074CK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1074CK 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 LT1074CK?
For technical support, including LT1074CK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1074CK requirements.
6.How does Aetrix verify that LT1074CK is sourced from the original manufacturer or authorized distributors?
All LT1074CK 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 LT1074CK meets industry standards.
7.What is the process for return or replacement of LT1074CK?
All LT1074CK units undergo pre-shipment inspection (PSI). If there is an issue with LT1074CK, 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 LT1074CK part is unused and in its original packaging.
Return procedure for LT1074CK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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