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Analog Devices Inc. LT1074IT#PBF
- Part No.:
- LT1074IT#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-220-5
- Datasheet:
-
LT1074IT#PBF.pdf
- Description:
- IC REG BUCK BST ADJ 5.5A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:208
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Product details
Overview
LT1074IT#PBF from Analog Devices (formerly Linear Technology) is a 5A monolithic bipolar step-down switching regulator in TO-220-5 package, operating from 8V to 60V input, delivering adjustable output from 2.5V to 50V at up to 5A continuous, with 100kHz fixed-frequency operation and true analog multiplier-based feedback for fast line transient response. It enables high-current buck, tapped-inductor buck (10A at 5V), positive-to-negative, and negative boost topologies in industrial power supplies.
For engineers reviewing the LT1074IT#PBF datasheet, LT1074IT#PBF pinout, LT1074IT#PBF application, or LT1074IT#PBF equivalent, key selection considerations include its 5A onboard Darlington switch, programmable current limit (6.5A default), 8.5mA quiescent current, micropower shutdown mode, and −40°C to +85°C industrial temperature rating - all critical for rugged DC/DC conversion in embedded power systems.
Technical Context
The LT1074IT#PBF implements a classic buck topology enhanced by an on-chip analog multiplier in the error amplifier feedback loop, making loop gain independent of input voltage and enabling near-instantaneous response to VIN transients. Its Darlington NPN switch supports 40V swing below ground, enabling tapped-inductor configurations and inverting topologies.
It features pulse-by-pulse current limiting with ≈600ns detection time, frequency downshifting (100kHz → 20kHz) when FB drops below 1.3V to maintain control under short-circuit, and a dedicated ILIM pin allowing external resistor programming of current limit down to zero - all implemented without external sense resistors or timing components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5A continuous (onboard switch); supports 10A via tapped-inductor buck configuration |
| Input Voltage Range | 8V to 60V (buck mode); self-boot enables ≥5V operation in inverting/boost modes |
| Switching Frequency | 100kHz nominal; auto-downshifts to 20kHz at low FB voltage to sustain control during short-circuit |
| Current Limit | 6.5A typical (ILIM open); adjustable down to zero via external resistor on ILIM pin |
| Quiescent Current | 8.5mA in normal operation; 140–300µA in micropower shutdown mode |
| Reference Voltage | 2.21V ±1.5% over full temperature range; used for precise output voltage setting via FB divider |
| Operating Temperature | −40°C to +85°C ambient (Industrial grade); junction max 125°C |
Pinout & Package
LT1074IT#PBF is housed in a 5-lead plastic TO-220 package (T package) with tab connected to GND. The case serves as thermal and electrical ground, requiring direct soldering to copper pour for thermal management (θJA = 35°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply & switch emitter | Supplies internal circuitry and serves as high-current switch return path; must be bypassed with low-ESR capacitor close to pin |
| VSW | Switch collector output | Drives external inductor/diode; swings up to 40V below GND - enables inverting and tapped-buck topologies |
| GND | Ground reference | Reference for internal 2.21V bandgap; must connect directly to low-current output node to avoid load regulation error |
| VC | Error amplifier output | Compensation node for loop stability; connects to series RC network from VC to GND for frequency compensation |
| FB/SENSE | Inverting input of error amplifier | Monitors output via resistor divider; 2.21V reference sets regulated output: VOUT = 2.21V × (1 + R1/R2) |
Key Features
| Feature | Design Value |
|---|---|
| Analog multiplier feedback | Eliminates input-voltage dependence in loop gain, enabling <10µs line transient recovery and stable regulation across wide VIN range |
| Programmable current limit | ILIM pin accepts external resistor to set trip point from 0A to 6.5A - no sense resistor required, simplifying PCB layout |
| Micropower shutdown | Reduces supply current to ≤300µA; shutdown threshold at 0.3V (full off) and 2.45V (duty-cycle disable), supporting UVLO and soft-start |
| Frequency downshifting | Automatically lowers switching frequency from 100kHz to 20kHz as FB drops below 1.3V - maintains current control during severe overload or short-circuit |
| 40V negative swing capability | VSW pin rated to −35V vs GND, enabling direct drive of tapped inductors and robust positive-to-negative converter designs |
Applications
| Industrial DC/DC Power Supply | High-Current Tapped-Inductor Buck |
|---|---|
Use Scenario: Converting 24V or 48V factory bus to 5V/3.3V for PLC I/O modules and sensor interfaces under harsh EMI and thermal conditions. IC Role / Device Role / Timing Role: Primary buck controller with integrated 5A switch, handling full load regulation, current limiting, and thermal protection autonomously. Use Value: Eliminates external MOSFET and gate driver; 8.5mA quiescent current extends uptime in standby; industrial temp rating ensures reliability in uncooled enclosures. | Use Scenario: Generating 5V@10A from 24V input for FPGA core power in test equipment where space and component count are constrained. IC Role / Device Role / Timing Role: Controller driving tapped-inductor topology; leverages VSW's −40V swing capability to enable dual-path current delivery. Use Value: Achieves 10A output using single IC and one inductor - reduces BOM cost and board area versus dual-phase discrete solutions. |
| Positive-to-Negative Converter | Field-Deployable Battery-Powered Instrument |
Use Scenario: Generating −5V rail from 12V battery for op-amp biasing and signal conditioning in portable data loggers. IC Role / Device Role / Timing Role: Inverting buck-boost controller; uses LT1074IT#PBF in positive-to-negative configuration with grounded output capacitor. Use Value: No need for isolated transformer or charge-pump IC; 100kHz operation minimizes filter size; self-boot allows start-up from 5V input if battery sags. | Use Scenario: Powering microcontroller, display, and wireless module from 9–36V LiFePO₄ or lead-acid battery in remote environmental monitors. IC Role / Device Role / Timing Role: Main system regulator with programmable current limit and micropower shutdown to extend battery life during sleep cycles. Use Value: 140µA shutdown current enables multi-year operation on 10Ah battery; UVLO hysteresis prevents brownout oscillation during battery discharge. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3632EMSE#PBF | 4A synchronous buck, 3.6–55V input, 1MHz switching, integrated MOSFETs, lower IQ (25µA) | Higher efficiency at light loads; requires external compensation; no negative-swing capability | Preferred for compact, high-efficiency designs where 10A tapped-buck or inverting topologies are not needed |
| LM2678S-5.0/NOPB | 5A buck, 8–40V input, 5V fixed output, 260kHz, no ILIM pin, no analog multiplier feedback | Fixed 5V output only; slower line transient response; no programmable current limit or shutdown control | Suitable for cost-sensitive, fixed-output applications where design flexibility and dynamic performance are secondary |
Compared with LTC3632EMSE#PBF and LM2678S-5.0/NOPB, the LT1074IT#PBF uniquely supports multi-topology operation (buck, inverting, tapped-inductor), offers analog multiplier-based fast line regulation, and provides pin-programmable current limiting - making it irreplaceable for rugged, flexible industrial DC/DC designs requiring >5A scalable output.
Availability
LT1074IT#PBF is available at Aetrix Electronics and suitable for industrial power supplies, field instrumentation, battery-powered test equipment, and ruggedized embedded systems requiring stable component supply and long-term manufacturability.
Supply support for LT1074IT#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 legacy high-performance analog and power management portfolio with full datasheet, application note, and technical support continuity.
The LT1074 product line was designed for robust, topology-flexible DC/DC conversion in industrial, telecom, and instrumentation applications where reliability, wide input range, and multi-configuration capability outweigh the need for ultra-high efficiency or ultra-small footprint.
FAQ
What is the maximum input voltage rating for the LT1074IT#PBF?
The LT1074IT#PBF has an absolute maximum input voltage rating of 45V. Its recommended operating input voltage range in buck configuration is 8V to 60V, enabled by internal self-boot circuitry - but sustained operation above 45V risks exceeding absolute maximum ratings and is not guaranteed. Always observe the 45V VIN limit per Absolute Maximum Ratings table.
Can the LT1074IT#PBF be used in a positive-to-negative converter configuration?
Yes, the LT1074IT#PBF can be configured as a positive-to-negative converter. Its VSW pin is rated to swing 35V below ground, enabling direct connection to the center tap of an inductor or transformer. Application Note AN44 and Figure TA03 in the LT1074/LT1076 datasheet provide validated schematics and component values for −5V@1A operation from 4.5–40V input.
How does the LT1074IT#PBF implement current limiting without an external sense resistor?
The LT1074IT#PBF integrates a current-sense circuit that monitors switch conduction via internal sensing elements. Current limit is set by the voltage on the ILIM pin, driven by an internal 320µA current source. With ILIM open, it self-clamps at ~4.5V, yielding 6.5A typical limit. An external resistor from ILIM to GND scales this limit linearly - no external sense resistor is required.
What is the purpose of the analog multiplier in the LT1074IT#PBF feedback loop?
The analog multiplier in the LT1074IT#PBF multiplies the error amplifier output by a signal inversely proportional to VIN, ensuring the duty cycle command remains independent of input voltage. This makes loop gain constant across the entire input range, resulting in dramatically improved line transient response - typically <10µs recovery - compared to conventional buck controllers.
Does the LT1074IT#PBF require external frequency compensation, and where is it connected?
Yes, the LT1074IT#PBF requires external frequency compensation for stable operation. Compensation is applied between the VC pin and GND using a series RC network (e.g., 10kΩ + 100nF). This network sets the dominant pole and zero to ensure phase margin >45° across load and input variations. The FB pin also connects to the same divider used for output voltage setting.
LT1074IT#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, Flyback
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 45V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 35V
- Current - Output:
- 5.5A (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
LT1074IT#PBF FAQ
1.How can I place an order for LT1074IT#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1074IT#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 LT1074IT#PBF reliable?
The price and inventory of LT1074IT#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1074IT#PBF is usually 5 days.
3.What payment methods are accepted for LT1074IT#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1074IT#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1074IT#PBF?
LT1074IT#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1074IT#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 LT1074IT#PBF?
For technical support, including LT1074IT#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1074IT#PBF requirements.
6.How does Aetrix verify that LT1074IT#PBF is sourced from the original manufacturer or authorized distributors?
All LT1074IT#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 LT1074IT#PBF meets industry standards.
7.What is the process for return or replacement of LT1074IT#PBF?
All LT1074IT#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1074IT#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 LT1074IT#PBF part is unused and in its original packaging.
Return procedure for LT1074IT#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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