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Analog Devices Inc. LT1371IR#TRPBF
- Part No.:
- LT1371IR#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LT1371IR#TRPBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 3A DDPAK-7
- Quantity:
- Payment:
- Shipping:
Inventory:4,845
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Product details
Overview
LT1371IR#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 regulates positive or negative outputs, features 1.245V reference voltage, 4mA typical quiescent current, and operates down to 2.7V input voltage - ideal for compact laptop computer supplies and dual-output flyback converters.
For engineers reviewing the LT1371IR#TRPBF datasheet, LT1371IR#TRPBF pinout, LT1371IR#TRPBF application, or LT1371IR#TRPBF equivalent, key selection considerations include its 3A internal switch current limit, ±2.49V negative feedback reference, 12µA shutdown supply current, synchronization capability up to 800kHz, and thermal design implications of its 7-lead DD package with exposed tab.
Technical Context
The LT1371IR#TRPBF implements current-mode control with adaptive anti-saturation driver circuitry, enabling rapid switch turn-off and minimizing driver dissipation. Its error amplifier features nonlinear transconductance (1100–1900 µmho) that increases 10× when FB exceeds VREF by 40mV, reducing output overshoot during startup or overload recovery.
Oscillator frequency shifting (5:1 reduction below 0.6V FB) protects external components under overload, while VC pin serves triple function: loop compensation node, soft-start control point, and current-limit adjustment interface. The device supports external synchronization between 600kHz–800kHz and enters idle mode when VC is pulled below 0.8V threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 450–550 kHz (typ. 500 kHz); enables use of small 4.7µH inductors and reduces filter component size. |
| Integrated Switch Current Limit | 3.0–5.4 A (duty-cycle dependent); provides pulse-by-pulse overcurrent protection without external sensing. |
| Reference Voltage (FB) | 1.230–1.260 V; sets output voltage via resistor divider; low drift (0.03%/V line regulation) ensures stable regulation across input range. |
| Negative Feedback Reference (NFB) | –2.540 to –2.440 V; enables direct negative output regulation without external op-amps or level-shifting circuits. |
| Quiescent Supply Current | 4 mA typ.; minimizes no-load power loss in battery-powered systems like portable computing supplies. |
| Shutdown Supply Current | 12 µA typ.; allows ultra-low-power standby mode in always-on embedded subsystems. |
| Minimum Input Voltage | 2.4–2.7 V; supports single-cell Li-ion or multi-cell NiMH operation without pre-regulation. |
| Output Switch Breakdown Voltage | 35 V; defines maximum allowable VSW swing; constrains usable output voltage in boost configurations. |
Pinout & Package
LT1371IR#TRPBF is housed in a 7-lead plastic DD (R) package with exposed conductive tab thermally and electrically connected to GND. The tab must be soldered directly to a large copper area on the PCB for thermal management (θJA = 30°C/W with 0.5 in² ground plane).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| TAB | Thermal & Electrical Ground | Primary heat path; must be connected to PCB ground plane for thermal performance and EMI control. |
| 1 - GND | Signal Ground Reference | Return path for internal bias circuits; tie directly to ground plane near IC body. |
| 2 - VIN | Input Supply Input | Bypass with ≥10µF low-ESR capacitor; undervoltage lockout activates below 2.5V. |
| 3 - S/S | Shutdown / Sync Dual Function | Logic-low (≤0.6V) enables shutdown (12µA IQ); 600–800kHz AC signal synchronizes switching. |
| 4 - VSW | Power Switch Collector | High-di/dt node; keep trace short and wide to minimize ringing and EMI radiation. |
| 5 - GND | Second Ground Terminal | Provides low-inductance return for high-frequency switch current; connect to same ground plane as Pin 1 and TAB. |
| 6 - NFB | Negative Output Feedback Input | Senses –2.49V reference; bias current (–30µA typ.) must be accounted for in resistor divider design. |
| 7 - FB | Positive Output Feedback Input | Senses 1.245V reference; input current ≤550nA allows high-value dividers with minimal error. |
| 8 - VC | Error Amplifier Output / Compensation | External RC network sets loop stability; clamping controls soft-start and current limit. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode control architecture | Enables immediate line transient response and simplifies loop compensation across wide input/output ranges. |
| Nonlinear error amplifier transconductance | Reduces output overshoot by 10× gain increase at startup/overload - eliminates need for external soft-start circuitry. |
| Oscillator frequency shifting | 5:1 frequency reduction below 0.6V FB prevents component stress during sustained overload or short-circuit conditions. |
| Dual polarity regulation capability | Single IC regulates both +12V and –12V outputs simultaneously using FB and NFB pins - reduces BOM count in dual-rail systems. |
| Adaptive anti-saturation driver | Monitors switch saturation onset in real time and adjusts drive current to minimize VCE(sat) and switching losses. |
| Logic-level shutdown & sync interface | Eliminates need for level translators; S/S pin accepts standard CMOS/TTL signals for system-level power sequencing. |
Applications
| Laptop Computer Power Supply | Dual-Output Flyback Converter |
|---|---|
|
Use Scenario: Generating 12V rail from 5V USB-C or 3.3V system bus in ultraportable notebooks with strict size and efficiency constraints. IC Role / Device Role / Timing Role: Primary DC-DC controller implementing boost topology with integrated 3A switch and 500kHz oscillator. Use Value: Enables compact layout using 4.7µH inductor and surface-mount tantalum output capacitors, achieving >85% efficiency at 0.7A load. |
Use Scenario: Simultaneous generation of isolated +15V and –15V rails for op-amp biasing in industrial data acquisition modules. IC Role / Device Role / Timing Role: Single-controller flyback regulator using FB and NFB pins for independent positive/negative output regulation. Use Value: Eliminates second controller IC and associated compensation networks, reducing solution size by 35% and BOM cost by $0.82. |
| Inverting DC-DC Supply | Programmable Negative Bias Generator |
|
Use Scenario: Converting 3.3V logic supply into –5V for RS-232 transceivers or analog sensor biasing in space-constrained IoT edge nodes. IC Role / Device Role / Timing Role: Inverting topology controller with NFB pin regulating –2.49V reference and VC pin enabling adjustable current limit. Use Value: Achieves –5.02V ±1.2% accuracy across 10mA–200mA load with no external op-amp or charge pump. |
Use Scenario: Generating user-adjustable negative bias (–3V to –12V) for LCD contrast control or photodiode reverse bias in medical handheld devices. IC Role / Device Role / Timing Role: Programmable inverting regulator where FB and NFB pins are used with DAC-controlled divider to set output voltage. Use Value: Supports 12-bit voltage resolution via digital potentiometer interface on VC pin, maintaining <1% line/load regulation. |
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 3.3MHz switching frequency; 2.5A switch; requires external compensation; no NFB pin. | Optimized for ultra-small footprint (2mm × 3mm DFN); unsuitable for dual-polarity or inverting designs. | Select when board area is critical and only positive output regulation is needed; avoid if negative rail support is required. |
| TPS55340RTER | 40V input rating; 5A switch; integrated FET driver; no negative feedback capability; 2.2MHz fixed frequency. | Targeted at automotive and industrial 12V/24V input systems; lacks NFB functionality and sub-3V start-up. | Choose for higher input voltage robustness and higher output current; not drop-in compatible due to different pinout and missing NFB function. |
Compared with LT1371IR#TRPBF, LT3573EDD#TRPBF offers smaller solution size but sacrifices dual-polarity regulation and low-voltage operation, while TPS55340RTER delivers higher power and input voltage range but removes the unique NFB-based negative output capability central to LT1371IR#TRPBF's value in mixed-rail systems.
Availability
LT1371IR#TRPBF is available at Aetrix Electronics and suitable for laptop computer supplies, dual-output flyback converters, inverting DC-DC supplies, and programmable negative bias generators requiring stable component supply across extended temperature and long production lifecycles.
Supply support for LT1371IR#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT1371 product line was developed specifically for high-efficiency, multi-topology DC-DC conversion in space- and power-constrained portable electronics, emphasizing integration of 3A switching, dual-polarity feedback, and ultra-low quiescent current.
FAQ
What is the maximum output voltage achievable with LT1371IR#TRPBF in boost configuration?
The LT1371IR#TRPBF has a 35V output switch breakdown voltage (BVSW). In boost topology, maximum safe output voltage is limited to ≤32V to maintain margin against transients and ensure reliable operation. Exceeding this risks switch avalanche failure, especially under load step or thermal stress. Always verify VSW stress with worst-case duty cycle and input ripple in final design.
Can LT1371IR#TRPBF regulate both positive and negative outputs simultaneously?
Yes, the LT1371IR#TRPBF supports simultaneous regulation of positive and negative outputs using its dedicated FB and NFB pins - as demonstrated in the "Dual Output Flyback Converter with Overvoltage Protection" reference design. When both pins are active, the IC prevents either rail from exceeding its setpoint, making it suitable for split-rail analog circuitry without secondary controllers.
What is the purpose of the VC pin on LT1371IR#TRPBF, and how is it used in practice?
The VC pin on LT1371IR#TRPBF is the error amplifier output and serves three critical functions: (1) frequency compensation node (via RC network), (2) soft-start control point (capacitor coupling enables controlled ramp-up), and (3) current limit adjustment interface (external clamp reduces peak switch current). Its voltage ranges from ~1V (light load) to ~1.9V (full load), and pulling it below 0.8V forces idle mode.
Does LT1371IR#TRPBF require external components for synchronization, and what is the valid frequency range?
No external components are required for synchronization of LT1371IR#TRPBF - the S/S pin accepts a logic-level square wave directly. Valid synchronization frequency is guaranteed from 600kHz to 800kHz; operation above 700kHz may reduce slope compensation amplitude and risk subharmonic oscillation at >50% duty cycle. For robust sync, use clean TTL/CMOS waveform with <10ns rise/fall times.
How does the LT1371IR#TRPBF handle thermal management in the 7-lead DD package?
The LT1371IR#TRPBF in the 7-lead DD (R) package relies on its exposed conductive tab for primary heat dissipation. Thermal resistance is specified as θJA = 30°C/W when soldered to 0.5 in² of 1 oz copper over an internal ground plane. Layout must connect the tab and all GND pins directly to this plane; insufficient copper area or poor solder joint quality can raise junction temperature beyond 125°C, triggering thermal shutdown.
LT1371IR#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- 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:
- DDPAK-7
LT1371IR#TRPBF FAQ
1.How can I place an order for LT1371IR#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1371IR#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 LT1371IR#TRPBF reliable?
The price and inventory of LT1371IR#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1371IR#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1371IR#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1371IR#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1371IR#TRPBF?
LT1371IR#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1371IR#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 LT1371IR#TRPBF?
For technical support, including LT1371IR#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1371IR#TRPBF requirements.
6.How does Aetrix verify that LT1371IR#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1371IR#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 LT1371IR#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1371IR#TRPBF?
All LT1371IR#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1371IR#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 LT1371IR#TRPBF part is unused and in its original packaging.
Return procedure for LT1371IR#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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