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Analog Devices Inc. LT1371CSW#TRPBF
- Part No.:
- LT1371CSW#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
LT1371CSW#TRPBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 3A 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,317
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Product details
Overview
LT1371CSW#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic 500kHz current-mode switching regulator IC with integrated 3A power switch, designed for boost, buck, flyback, inverting, and Cuk topologies. It delivers up to 0.8A output current in a 12V boost configuration from 5V input, features 1.245V internal reference, ±2.49V negative feedback reference, and operates down to 2.7V input voltage - ideal for portable laptop power supplies and dual-polarity flyback converters.
For engineers reviewing the LT1371CSW#TRPBF datasheet, LT1371CSW#TRPBF pinout, LT1371CSW#TRPBF application, or LT1371CSW#TRPBF equivalent, key selection criteria include its 500kHz switching frequency, 3A integrated switch, dual positive/negative output regulation capability, shutdown current of 12µA, and SO-20 wide-body package thermal performance (θJA = 50°C/W).
Technical Context
The LT1371CSW#TRPBF implements current-mode control with adaptive anti-saturation driver circuitry that dynamically adjusts gate drive to minimize switch saturation and enable rapid turn-off. Its error amplifier features nonlinear transconductance (1100–1900 µmho), increasing 10× when FB exceeds VREF by 40mV to suppress startup/overload overshoot.
Oscillator frequency shifting (5:1 reduction below 0.6V FB) protects external components during overload, while VC pin serves triple function: compensation node, soft-start control point, and current-limit adjustment interface. The device supports external synchronization from 600–800kHz and includes dedicated SHDN and SYNC pins in the SW package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 450–550 kHz typical; enables use of compact 4.7µH inductors and reduces filter size. |
| Integrated Switch Current Limit | 3.0–5.4 A; provides pulse-by-pulse overcurrent protection without external sensing. |
| Reference Voltage (FB) | 1.245 V ±15 mV; sets positive output voltage via resistor divider with minimal bias current error. |
| Negative Feedback Reference (NFB) | –2.490 V ±50 mV; enables direct regulation of negative outputs without auxiliary amplifiers. |
| Quiescent Supply Current | 4 mA typical; ensures high light-load efficiency in battery-powered systems. |
| Shutdown Supply Current | 12 µA typical; extends battery life during system sleep modes. |
| Minimum Input Voltage | 2.7 V; supports single-cell Li-ion and multi-cell alkaline input sources. |
| Output Switch Breakdown Voltage | 35 V; accommodates 12V boost outputs with margin for transient spikes. |
Pinout & Package
LT1371CSW#TRPBF uses a 20-lead plastic SO wide (SW) package with exposed ground pads (pins 4–7 and 14–17) for enhanced thermal dissipation (θJA = 50°C/W). Ground pins are distributed across both sides to minimize loop inductance and EMI.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC | Compensation / Error Amplifier Output | Interface for RC frequency compensation; controls soft-start, current limit, and loop stability. |
| FB | Positive Feedback Input | Inverting input of main error amplifier; referenced to 1.245V for positive output regulation. |
| NFB | Negative Feedback Input | Connects to –2.49V reference for negative output sensing; includes 100kΩ internal source resistor. |
| GND (Pins 3,4,5,6,14,15,16,17) | Power & Signal Ground | Multiple low-inductance ground paths reduce noise coupling and improve thermal conduction. |
| SHDN | Active-Low Shutdown Control | Pull ≤0.6V to reduce supply current to 12µA; logic-compatible with microcontroller GPIO. |
| SYNC | External Synchronization Input | Accepts 600–800kHz square wave to align switching with system clock and reduce EMI. |
| VIN | Input Supply | Bypass with ≥10µF low-ESR capacitor; UVLO triggers below 2.5V to prevent erratic operation. |
| VSW | Switch Node | Collector of internal 3A NPN switch; requires shortest possible PCB trace to diode/capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode control architecture | Enables immediate line transient response and simplifies loop compensation under varying load/input conditions. |
| Nonlinear error amplifier transconductance | Reduces output voltage overshoot during startup and overload recovery by 10× gain boost at critical threshold. |
| Dual-reference regulation (FB + NFB) | Allows single IC to regulate both positive and negative outputs simultaneously in flyback configurations. |
| Oscillator frequency shifting | Reduces switching frequency 5:1 when FB drops below 0.6V, limiting peak switch current during overload. |
| Adaptive anti-saturation driver | Minimizes switch conduction losses and enables fast turn-off without external snubbers. |
| Logic-level shutdown & sync inputs | Eliminates need for level-shifting circuitry; compatible with 3.3V/5V microcontrollers and FPGA I/O. |
Applications
| Laptop Computer Supplies | Multiple Output Flyback Supplies |
|---|---|
Use Scenario: Step-up conversion from single-cell Li-ion (3.0–4.2V) to 5V/12V rails for USB peripherals and display backlight drivers. IC Role / Device Role / Timing Role: Primary controller in non-isolated boost topology; regulates output using FB pin and manages inductor current via current-mode sensing. Use Value: 4mA quiescent current extends battery runtime; 500kHz switching allows use of 4.7µH shielded inductors under 3mm height. |
Use Scenario: Dual-output isolated flyback converter delivering +12V and –12V from 24V DC input in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Regulates both polarities simultaneously using FB and NFB pins; oscillator frequency shifting prevents transformer saturation during load imbalance. Use Value: Eliminates need for separate regulators or optocoupler feedback loops; maintains ±1% output accuracy across –40°C to 85°C ambient. |
| Inverting Supplies | Boost Regulators |
Use Scenario: Generation of –5V rail from 3.3V system supply in analog sensor signal conditioning circuits. IC Role / Device Role / Timing Role: Configured in inverting topology; NFB pin senses negative output and drives FB pin internally to maintain regulation. Use Value: Achieves –5.0V ±2% with <10mV ripple using standard 10µH inductor and Schottky diode; no external op-amp required. |
Use Scenario: 5V-to-12V boost converter powering Ethernet PHYs and PoE controllers in network edge devices. IC Role / Device Role / Timing Role: High-efficiency switcher with 3A integrated transistor; VC pin used for soft-start to limit inrush into 22µF ×2 output capacitors. Use Value: Delivers 0.7A at 90% efficiency; synchronization to system clock (700kHz) reduces conducted EMI peaks in 150kHz–30MHz band. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3573EDD#TRPBF | Higher 2.5MHz switching frequency; 2.5A switch; requires external compensation; no NFB pin. | Optimized for ultra-compact designs with <2.2µH inductors; lacks native negative output support. | Choose for space-constrained 3.3V-input boost where footprint matters more than dual-polarity capability. |
| TPS55340RTER | 3.5A switch; 1.2MHz fixed frequency; integrated soft-start; no negative feedback pin; TI WEBENCH support. | Targeted at cost-sensitive consumer power; requires external feedback network for negative outputs. | Prefer for high-volume production with TI ecosystem integration, but add external op-amp for –VOUT regulation. |
Compared with LT3573EDD#TRPBF and TPS55340RTER, the LT1371CSW#TRPBF uniquely supports true dual-polarity regulation without external amplifiers, retains legacy 500kHz frequency for EMI filtering compatibility, and offers lower quiescent current (4mA vs ≥6mA) - making it optimal for low-power industrial and portable systems requiring both +V and –V rails.
Availability
LT1371CSW#TRPBF is available at Aetrix Electronics and suitable for laptop computer supplies, multiple-output flyback converters, inverting supplies, and boost regulators requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1371CSW#TRPBF 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 continues to manufacture and support its high-performance power management portfolio with rigorous automotive and industrial qualification standards.
The LT1371 product line was engineered for flexible, high-efficiency DC/DC conversion in portable and industrial equipment - emphasizing dual-polarity regulation, low IQ, and robust thermal design in surface-mount packages.
FAQ
What is the maximum output current achievable with LT1371CSW#TRPBF in a boost configuration?
The LT1371CSW#TRPBF supports up to 0.8A output current in a 5V-to-12V boost application, as verified in the Typical Application diagram (TA02) with 4.7µH inductor and 22µF ×2 output capacitance. This limit arises from thermal constraints (θJA = 50°C/W) and the 3A switch's duty-cycle-dependent current limit - not absolute peak rating. Derating is required above 70°C ambient.
Can LT1371CSW#TRPBF regulate both positive and negative outputs simultaneously?
Yes, the LT1371CSW#TRPBF can regulate both polarities concurrently using FB and NFB pins, as confirmed in the Dual Polarity Output Voltage Sensing section. In such configurations, the IC prevents either output from exceeding its setpoint - e.g., in a dual-output flyback, the unloaded rail is clamped while the loaded rail sags slightly, ensuring safe no-load operation.
What is the purpose of the VC pin on LT1371CSW#TRPBF, and how is it used in practice?
The VC pin on LT1371CSW#TRPBF serves three critical functions: (1) frequency compensation node (RC network sets dominant pole/zero), (2) soft-start control (capacitor coupling enables controlled voltage ramp), and (3) current limit adjustment (external clamp lowers trip threshold). Its voltage ranges from ~1.0V (light load) to ~1.9V (full load), directly reflecting error amplifier output.
Does LT1371CSW#TRPBF support external clock synchronization, and what is the valid frequency range?
Yes, LT1371CSW#TRPBF supports external synchronization via the dedicated SYNC pin (pin 9), with guaranteed operation from 600kHz to 800kHz. The datasheet specifies this range explicitly in Electrical Characteristics and warns against >700kHz operation without increased inductor value due to reduced slope compensation amplitude - a design constraint confirmed in Applications Information.
What package type and thermal characteristics apply to LT1371CSW#TRPBF?
LT1371CSW#TRPBF uses a 20-lead plastic SO wide (SW) package with θJA = 50°C/W and θJC = 4°C/W. Thermal resistance varies with PCB copper area: ~40°C/W with 0.75 in² of 1 oz copper, rising to 50°C/W with 0.33 in². Heat is conducted through pins 4–7 and 14–17 (all GND), not via an exposed pad - distinct from QFN or DFN variants.
LT1371CSW#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost, Cuk, Flyback, Forward Converter, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 1.245V
- Voltage - Output (Max):
- 35V (Switch)
- Current - Output:
- 3A (Switch)
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
LT1371CSW#TRPBF FAQ
1.How can I place an order for LT1371CSW#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1371CSW#TRPBF 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 LT1371CSW#TRPBF reliable?
The price and inventory of LT1371CSW#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1371CSW#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1371CSW#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1371CSW#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1371CSW#TRPBF?
LT1371CSW#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1371CSW#TRPBF 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 LT1371CSW#TRPBF?
For technical support, including LT1371CSW#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1371CSW#TRPBF requirements.
6.How does Aetrix verify that LT1371CSW#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1371CSW#TRPBF 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 LT1371CSW#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1371CSW#TRPBF?
All LT1371CSW#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1371CSW#TRPBF, 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 LT1371CSW#TRPBF part is unused and in its original packaging.
Return procedure for LT1371CSW#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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