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Texas Instruments LM3411AM5X-5.0/NOPB
- Part No.:
- LM3411AM5X-5.0/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3411AM5X-5.0/NOPB.pdf
- Description:
- IC VREF SHUNT 0.5% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:801
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Product details
Overview
LM3411AM5X-5.0/NOPB from Texas Instruments is a precision 5-V fixed-output shunt regulator with ±0.5% initial tolerance (A-grade), designed to drive optocouplers in isolated DC-DC feedback loops. It features an open-emitter NPN output capable of 15 mA sink current, internal bandgap reference with curvature correction, and externally accessible COMP pin for loop compensation. It operates across –40°C to +125°C and is used in flyback converters delivering 5 V at up to 1.5 A.
For engineers reviewing the LM3411AM5X-5.0/NOPB datasheet, LM3411AM5X-5.0/NOPB pinout, LM3411AM5X-5.0/NOPB application, or LM3411AM5X-5.0/NOPB equivalent, key selection criteria include regulation accuracy over temperature, optocoupler drive capability, COMP pin accessibility for stability tuning, and SOT-23 package compatibility with space-constrained isolated power supplies.
Technical Context
The LM3411AM5X-5.0/NOPB implements a precision shunt regulation architecture using an internally compensated op-amp, trimmed bandgap reference, and integrated NPN output transistor. Its regulation voltage is set by internal feedback resistors (70–118 kΩ) and stabilized via external RC compensation between COMP and OUT pins.
It functions as a secondary-side voltage reference and error amplifier in isolated topologies-sensing output voltage at +IN relative to GND, then sinking current from OUT into an optocoupler LED to adjust primary-side PWM duty cycle. The no-connection pin (Pin 3) is thermally tied to PCB for improved heat transfer.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Regulation Voltage | 5.000 V ±0.5% at 25°C; ±1% over –40°C to +125°C - ensures stable feedback reference without trimming |
| Output Current Range | 20 μA to 15 mA - supports direct optocoupler LED drive across light-load to full-load conditions |
| Quiescent Current | 85–110 μA at 25°C - enables high-efficiency operation in standby and light-load modes |
| Output Saturation Voltage | 1.0–1.2 V at 15 mA - defines minimum headroom needed across optocoupler LED for reliable turn-on |
| Transconductance (Gm) | 3.3 mA/mV (typ.) at 25°C, 1–15 mA range - determines loop gain and transient response sensitivity |
| Output Noise | 80 μVRMS, 10 Hz–10 kHz - low noise preserves regulation accuracy in sensitive feedback paths |
| Thermal Resistance (RθJA) | 178.6°C/W - defines maximum power dissipation limit (300 mW at 25°C ambient) for SOT-23 layout |
Pinout & Package
LM3411AM5X-5.0/NOPB is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for surface-mount assembly in space-constrained power supplies.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| +IN (Pin 1) | Input sensing node | Connects to regulated output rail; voltage sensed here determines regulation point (5.0 V) |
| GND (Pin 2) | Reference ground | Common return for internal reference, amplifier, and external compensation network |
| NC (Pin 3) | No internal connection | Must be soldered to PCB copper pour for thermal conduction-no electrical function |
| COMP (Pin 4) | Inverting input of error amplifier | Accepts external RC compensation to stabilize closed-loop bandwidth and phase margin |
| OUT (Pin 5) | Open-emitter NPN collector | Sinks current into optocoupler LED; requires external pull-up to bias voltage (e.g., VCC) |
Key Features
| Feature | Design Value |
|---|---|
| Trimmed bandgap reference | Ensures ±0.5% initial accuracy and <±1% drift over –40°C to +125°C without external calibration |
| Integrated error amplifier | Provides programmable loop gain and phase compensation via COMP pin-eliminates need for external op-amp |
| Optocoupler-optimized output | Open-emitter NPN structure delivers 15 mA sink current with low saturation voltage (1.2 V max), directly driving common opto-LEDs |
| Internal feedback resistor network | Factory-trimmed 70–118 kΩ divider sets exact 5.0 V regulation-removes external resistor tolerance and layout errors |
| Thermally enhanced SOT-23 | Pin 3 NC terminal provides mechanical/thermal anchor to PCB-enables 300 mW power handling in compact footprint |
Applications
| Isolated Flyback Converter | Precision Buck Regulator |
|---|---|
Use Scenario: 5-V, 250-mA isolated flyback supply with input 15 V, operating at 80 kHz and requiring full input/output galvanic isolation. IC Role / Device Role / Timing Role: Secondary-side voltage reference and optocoupler driver-senses output at +IN, sinks current from OUT into opto-LED to modulate primary PWM duty cycle. Use Value: Enables ±0.5% output regulation without trim pots or precision resistors; COMP pin allows stability tuning for varying transformer leakage and load dynamics. | Use Scenario: 5-V, 1-A buck converter using LM2575, where line/load regulation must stay within ±1 mV across 8–18 V input and 100 mA–1 A load. IC Role / Device Role / Timing Role: Precision feedback reference and error amplifier-replaces internal LM2575 reference to improve accuracy and enable remote sensing. Use Value: Achieves ±0.5% output tolerance at 25°C and ±1% over temperature-eliminates need for 1% feedback resistors or post-production trimming. |
| High-Current Isolated Flyback | Precision LDO Regulator |
Use Scenario: 5-V, 1.5-A isolated flyback using LM2577 PWM controller, where secondary-side regulation must reject switching ripple and transients. IC Role / Device Role / Timing Role: Secondary-side reference and gain stage-provides voltage reference, error amplification, and optocoupler drive while isolating control loop from primary-side noise. Use Value: Internal RC filtering (1 Ω + 100 nF) minimizes ripple-induced regulation error; 80 μVRMS noise ensures stable feedback under dynamic load steps. | Use Scenario: 5-V, 1-A low-dropout linear regulator built with LM2941, requiring ±0.5% output accuracy and remote load sensing. IC Role / Device Role / Timing Role: High-accuracy voltage reference and error amplifier-replaces LM2941's internal reference to improve regulation and enable Kelvin sensing. Use Value: Delivers ±0.5% output at 25°C and ±1% over –40°C to +125°C-achieves near-perfect load regulation without 1% resistors or manual adjustment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDBVR | Adjustable 2.5 V reference (requires two external resistors); 100 mA sink capability; higher quiescent current (2–4 mA) | Requires external resistor network for 5 V setting; better suited for non-isolated or high-current feedback | Select when adjustable output or higher sink current is required; avoid if board space or trimming tolerance are constraints |
| LM4040C50IDBZR | Fixed 5.0 V shunt reference only (no amplifier or drive transistor); 15 mA max sink; no COMP pin or active drive capability | Cannot drive optocouplers directly; needs external transistor for isolation feedback | Select only for simple voltage monitoring or non-isolated reference; not suitable as drop-in replacement for optocoupler-driven feedback |
Compared with TL431ACDBVR and LM4040C50IDBZR, LM3411AM5X-5.0/NOPB uniquely integrates precision reference, error amplifier, and optocoupler driver in one SOT-23 package-reducing component count, eliminating resistor tolerance errors, and enabling stable isolated feedback without external gain stages.
Availability
LM3411AM5X-5.0/NOPB is available at Aetrix Electronics and suitable for isolated flyback converters, precision buck regulators, high-current DC-DC modules, and industrial LDO designs requiring stable component supply with guaranteed long-term sourcing.
Supply support for LM3411AM5X-5.0/NOPB 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
Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The LM3411 product line was developed specifically for precision secondary-side regulation in isolated power supplies-integrating reference, amplifier, and driver to simplify feedback design and improve system-level accuracy without trimming.
FAQ
What is the primary function of LM3411AM5X-5.0/NOPB in a power supply?
The LM3411AM5X-5.0/NOPB serves as a precision 5-V shunt regulator and optocoupler driver on the secondary side of isolated DC-DC converters. It senses output voltage at its +IN pin, compares it to an internal bandgap reference, and sinks current from its OUT pin into an optocoupler LED to adjust primary-side PWM duty cycle-enabling accurate, stable regulation without external trimming components.
Does LM3411AM5X-5.0/NOPB require external resistors to set its output voltage?
No. LM3411AM5X-5.0/NOPB has factory-trimmed internal feedback resistors (70–118 kΩ) that fix the regulation voltage at 5.000 V with ±0.5% initial tolerance. Unlike adjustable references such as TL431, it does not require external resistors-eliminating resistor tolerance errors, layout sensitivity, and calibration steps during manufacturing.
Can LM3411AM5X-5.0/NOPB drive standard optocouplers directly?
Yes. LM3411AM5X-5.0/NOPB features an open-emitter NPN output capable of sinking up to 15 mA with a saturation voltage of ≤1.2 V at full load. This allows direct drive of common optocouplers like PC817 or SFH615A without additional transistors-provided the optocoupler's forward voltage and CTR are compatible with the available bias voltage and current.
How is loop compensation implemented for LM3411AM5X-5.0/NOPB?
Loop compensation is implemented via the COMP pin (Pin 4), which exposes the inverting input of the internal error amplifier. A single capacitor (typically 10–100 nF) is connected between COMP and OUT to provide dominant-pole compensation. This external RC network stabilizes the closed-loop response and adjusts phase margin-critical for maintaining stability across varying transformer leakage inductance and load conditions.
What is the role of Pin 3 (NC) on LM3411AM5X-5.0/NOPB?
Pin 3 is a no-internal-connection terminal but must be soldered to PCB copper for thermal conduction. It acts as a thermal pad-improving heat transfer from the die to the board-and helps maintain junction temperature within limits (TJ ≤125°C) during continuous 15 mA operation. Leaving Pin 3 unconnected degrades thermal performance and may trigger premature thermal shutdown or reliability issues.
LM3411AM5X-5.0/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- SC-74A, SOT-753
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 15 mA
- Tolerance:
- ±0.5%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 80µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 115 µA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM3411AM5X-5.0/NOPB FAQ
1.How can I place an order for LM3411AM5X-5.0/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3411AM5X-5.0/NOPB 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 LM3411AM5X-5.0/NOPB reliable?
The price and inventory of LM3411AM5X-5.0/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3411AM5X-5.0/NOPB is usually 5 days.
3.What payment methods are accepted for LM3411AM5X-5.0/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3411AM5X-5.0/NOPB transactions.
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LM3411AM5X-5.0/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3411AM5X-5.0/NOPB 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 LM3411AM5X-5.0/NOPB?
For technical support, including LM3411AM5X-5.0/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3411AM5X-5.0/NOPB requirements.
6.How does Aetrix verify that LM3411AM5X-5.0/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3411AM5X-5.0/NOPB 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 LM3411AM5X-5.0/NOPB meets industry standards.
7.What is the process for return or replacement of LM3411AM5X-5.0/NOPB?
All LM3411AM5X-5.0/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3411AM5X-5.0/NOPB, 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 LM3411AM5X-5.0/NOPB part is unused and in its original packaging.
Return procedure for LM3411AM5X-5.0/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3411AM5X-5.0/NOPB Tags
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