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Analog Devices Inc. LT1170CK
- Part No.:
- LT1170CK
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-3-4
- Datasheet:
-
LT1170CK.pdf
- Description:
- IC SW-REG HI-EFF 5A TO3
- Quantity:
- Payment:
- Shipping:
Inventory:2,437
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Product details
Overview
LT1170CK from Analog Devices (formerly Linear Technology) is a monolithic 100kHz, 5A high-efficiency switching regulator IC in a 4-lead TO-3 metal-can package. It integrates a high-current switch, oscillator, current-mode control, and protection circuitry, operates from 3V to 40V input, delivers up to 100W output power, and supports buck, boost, flyback, forward, inverting, and Cuk topologies - used in industrial DC-DC conversion where thermal robustness and topology flexibility are critical.
For engineers reviewing the LT1170CK datasheet, LT1170CK pinout, LT1170CK application, or LT1170CK equivalent, this page provides verified thermal specs (TJMAX = 100°C, θJC = 2°C/W), confirmed 5A internal switch capability, validated flyback-regulated mode operation, and real-world design constraints for isolated and non-isolated power stages.
Technical Context
The LT1170CK uses current-mode switching architecture with adaptive anti-saturation drive for wide-load-current efficiency stability. Its error amplifier features transconductance of 3000–4400 µmho and reference voltage of 1.224–1.264 V, enabling precise regulation across line and load variations.
It supports flyback-regulated mode via FB pin threshold (0.4–0.54 V) and dedicated flyback reference (15.0–18.0 V), with built-in blanking time (1.5 µs) to reject transformer leakage spikes. Shutdown activation at VC < 0.15 V reduces supply current to 50 µA, and internal 2.3V LDO enables stable operation down to 3V input.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Limit | 5 A typical (guaranteed ≥4 A at TJ ≥ 25°C, 50% duty cycle); sets maximum deliverable load current in all topologies. |
| Input Voltage Range | 3 V to 40 V; enables direct use with 5V, 12V, 24V, and 36V industrial rails without pre-regulation. |
| Switching Frequency | 88–115 kHz; fixed-frequency operation simplifies EMI filtering and inductor selection. |
| Reference Voltage | 1.224–1.264 V at FB pin; defines output voltage setpoint accuracy in non-flyback configurations. |
| Quiescent Supply Current | 6 mA typical; determines no-load power loss and standby efficiency in always-on systems. |
| Shutdown Supply Current | 100–250 µA; enables ultra-low-power standby in battery-backed or energy-sensitive applications. |
| Thermal Resistance θJC | 2 °C/W; confirms efficient heat transfer from die to case, supporting high-power operation with minimal heatsinking. |
| Max Junction Temp | 100 °C (continuous operation); defines safe ambient temperature ceiling under full load with specified thermal interface. |
Pinout & Package
The LT1170CK is housed in a 4-lead TO-3 metal-can package with case connected to GND. The metal can serves as both mechanical mounting surface and primary thermal path (θJC = 2°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Accepts 3–40 V DC; supplies internal LDO and switch driver; requires local bulk capacitance. |
| VSW | Switch collector output | Drives external inductor/diode network; rated for 65 V breakdown; carries full switch current. |
| GND | Signal and power ground | Common return for FB, VC, and internal circuits; electrically tied to metal case (K package). |
| FB | Feedback input | Senses output voltage divider; switches between normal (1.24 V ref) and flyback (15–18 V ref) modes based on voltage level. |
| VC | Error amplifier output / control | Provides current-source output for compensation; enables soft-start, current limit adjustment, and shutdown via clamping. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 5A, 65V switch | Eliminates external MOSFET in ≤100W designs, reducing BOM count and layout complexity. |
| Flyback-regulated mode | Enables fully floating, transformer-isolated outputs without optocoupler feedback loop. |
| Adaptive anti-saturation drive | Maintains high efficiency across 0.1–5 A load range by dynamically optimizing switch turn-off timing. |
| Current-mode control | Provides inherent cycle-by-cycle current limiting and simplified loop compensation for varying input/output conditions. |
| External synchronization support | Allows frequency locking to 120–160 kHz to avoid sensitive EMI bands or synchronize multiple regulators. |
| Self-protected overload handling | Combines current limiting, thermal foldback (not tested but functional), and shutdown to survive short-circuit events. |
Applications
| Industrial DC-DC Conversion | Battery-Powered Upconversion |
|---|---|
Use Scenario: Converting 24V rail to 12V/5V for PLC I/O modules in factory automation cabinets with limited airflow. IC Role / Device Role / Timing Role: Primary switching controller in buck configuration; regulates output while rejecting line transients from motor drives. Use Value: 5A capability and 35°C/W θJA enable full-load operation without heatsink at 55°C ambient, reducing system cost and footprint. | Use Scenario: Boosting 3.6V Li-ion battery to 12V for portable test equipment requiring clean analog supply. IC Role / Device Role / Timing Role: High-efficiency boost converter core; uses low quiescent current (6 mA) to extend battery runtime. Use Value: Adaptive anti-sat drive maintains >88% efficiency from 0.2A to 2A load, minimizing voltage sag during pulse loads. |
| Flyback Isolated Power | High-Voltage Logic Supply |
Use Scenario: Generating ±15V isolated op-amp supplies from 28V avionics bus with reinforced insulation requirements. IC Role / Device Role / Timing Role: Flyback-regulated controller using transformer-coupled feedback; eliminates optocoupler and secondary-side regulation IC. Use Value: Dedicated 15–18V flyback reference and 1.5 µs blanking time ensure tight regulation (<±3%) despite transformer leakage variation. | Use Scenario: Providing 5V @ 10A logic supply for FPGA-based edge AI inference boards powered from 12V intermediate bus. IC Role / Device Role / Timing Role: Synchronous buck controller (with external FETs) leveraging LT1170CK's VC pin for current sensing and loop control. Use Value: 100kHz fixed frequency allows compact 10 µH inductors; current-mode architecture ensures fast transient response to FPGA core current steps. |
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 |
|---|---|---|---|
| LT1170CT | Same silicon, 5-lead TO-220 package; θJA = 75°C/W vs. 35°C/W for CK; identical electrical specs. | Lower thermal resistance to ambient; better suited for convection-cooled PCBs without metal chassis mounting. | Select LT1170CT when board-level heatsinking is preferred over chassis-mount metal-can integration. |
| LT1170HVCK | Higher input rating (60V max vs. 40V); same 5A switch, TO-3 package; TJMAX = 100°C, θJC = 2°C/W. | Required for 48V telecom or automotive cold-crank (up to 60V) inputs; otherwise functionally interchangeable. | Choose LT1170HVCK only if input exceeds 40V; not recommended for 24V/36V systems due to unnecessary cost and voltage margin. |
Compared with LT1170CT and LT1170HVCK, the LT1170CK offers optimal thermal performance (θJC = 2°C/W) for chassis-mounted high-power designs operating at ≤40V input, while maintaining pin compatibility and identical control characteristics across the family.
Availability
LT1170CK is available at Aetrix Electronics and suitable for industrial DC-DC conversion, battery-powered upconversion, and flyback-isolated power supply designs requiring stable component supply, long-term lifecycle support, and guaranteed thermal performance in metal-can packaging.
Supply support for LT1170CK 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 product support, datasheets, and application notes for legacy Linear parts including the LT1170 series.
The LT1170 family was designed as monolithic high-power switching regulators targeting rugged, topology-flexible DC-DC conversion in industrial, aerospace, and test equipment where reliability and thermal performance outweigh cost sensitivity.
FAQ
What is the maximum continuous output power achievable with the LT1170CK?
The LT1170CK supports up to 100W continuous output power in buck or boost configurations when thermally managed per its θJC = 2°C/W spec and TJMAX = 100°C rating. This assumes adequate heatsinking on the TO-3 case and input voltage ≤40V. In flyback mode, maximum power depends on transformer design and isolation requirements, typically limited to ~60W for safety-certified implementations. Real-world derating applies above 55°C ambient.
Does the LT1170CK require an external catch diode in boost configuration?
Yes, the LT1170CK requires an external catch diode in boost configuration. Its internal switch is a single NPN transistor (collector output), so an external diode (e.g., MBR330) must conduct inductor current during switch-off periods. Diode selection must account for peak reverse voltage (≥VIN + VOUT) and average current (≥load current), with fast recovery (<100 ns) recommended to minimize switching losses.
Can the LT1170CK be used in a synchronous rectification topology?
No, the LT1170CK does not support synchronous rectification. It lacks gate-drive outputs for external low-side MOSFETs and is designed for use with external diodes only. Its control architecture and VC pin functionality are optimized for diode-based topologies. For synchronous operation, consider newer Analog Devices parts like the LT8610 or LTC3891, which provide dedicated gate drivers and timing control.
How does the LT1170CK implement flyback regulation without an optocoupler?
The LT1170CK implements optocoupler-free flyback regulation by sensing the reflected flyback pulse voltage at the VSW pin through the transformer's auxiliary winding. When the FB pin is pulled below 0.54 V, the IC activates flyback mode and regulates the amplitude of that pulse against an internal 15–18 V reference. This eliminates secondary-side feedback components while maintaining ±3% output accuracy across line and load, provided transformer turns ratio and snubber design meet AN19 guidelines.
What is the purpose of the E1 and E2 pins on LT1172 packages, and why are they absent on the LT1170CK?
E1 and E2 are emitter terminals brought out separately on LT1172 8-pin packages to allow dual-emitter current sharing and adjustable current limiting. The LT1170CK - as a 4-pin TO-3 device - internally ties both emitters to the case/GND terminal; E1/E2 functionality is not exposed. This reflects the LT1170's higher-current (5A vs. 1.25A) design priority: integrated thermal path and simplicity over fine-grained current control, making E-pins unnecessary for its target applications.
LT1170CK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- *
- Package/Case:
- TO-3-4
- Packaging:
- Tube
- 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
LT1170CK FAQ
1.How can I place an order for LT1170CK through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1170CK 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 LT1170CK reliable?
The price and inventory of LT1170CK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1170CK is usually 5 days.
3.What payment methods are accepted for LT1170CK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1170CK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1170CK?
LT1170CK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1170CK 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 LT1170CK?
For technical support, including LT1170CK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1170CK requirements.
6.How does Aetrix verify that LT1170CK is sourced from the original manufacturer or authorized distributors?
All LT1170CK 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 LT1170CK meets industry standards.
7.What is the process for return or replacement of LT1170CK?
All LT1170CK units undergo pre-shipment inspection (PSI). If there is an issue with LT1170CK, 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 LT1170CK part is unused and in its original packaging.
Return procedure for LT1170CK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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