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Texas Instruments LM4128AMFX-2.5
- Part No.:
- LM4128AMFX-2.5
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM4128AMFX-2.5.pdf
- Description:
- IC VREF SERIES 0.1% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,885
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Product details
Overview
LM4128AMFX-2.5 from National Semiconductor is a precision micropower series voltage reference in SOT-23-5 package, delivering 2.5 V output with ±0.1% initial accuracy, 75 ppm/°C temperature coefficient, and 60 µA quiescent current. It features an enable pin for 3 µA shutdown mode and supports up to 20 mA load current - ideal for high-accuracy ADC/DAC biasing in portable instrumentation.
For engineers reviewing the LM4128AMFX-2.5 datasheet, LM4128AMFX-2.5 pinout, LM4128AMFX-2.5 application, or LM4128AMFX-2.5 equivalent, key selection considerations include dropout voltage (≤400 mV at 10 mA), stability with capacitive loads up to 10 µF, line regulation (50 ppm/V), load regulation (25–120 ppm/mA), and thermal hysteresis (75 ppm).
Technical Context
The LM4128AMFX-2.5 uses an internal band-gap-derived reference core optimized for low-power operation and minimal thermal drift. Its series architecture eliminates need for external stabilization capacitors while maintaining stability under capacitive loads up to 10 µF.
It integrates an enable control input (EN) referenced to VIN, with defined VIH/VIL thresholds (65%/35% of VIN), and operates across −40°C to +125°C junction temperature. Dropout is specified as VIN − VREF ≥ 400 mV at 10 mA load, supporting battery-powered systems down to ~2.9 V input.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.5 V nominal; ±0.1% initial accuracy at 25°C ensures ≤±2.5 mV absolute error before calibration |
| Temperature Coefficient | 75 ppm/°C max (A grade); contributes ≤±18.75 mV drift over −40°C to +125°C range |
| Quiescent Current | 60 µA typical; enables multi-year battery life in always-on sensor nodes drawing <100 µA total |
| Shutdown Current | 3 µA max when EN = 0 V; reduces system standby power by >95% vs active mode |
| Dropout Voltage | 400 mV max at 10 mA load; allows operation from single Li-ion cell (≥2.9 V) or 3.3 V rail with margin |
| Output Noise | 275 µVPP (0.1–10 Hz); supports 16-bit+ SAR ADCs without additional filtering |
| Load Regulation | 25–120 ppm/mA; maintains <±0.3 mV shift across full 0–20 mA load range |
Pinout & Package
SOT-23-5 package (NS MF05A), surface-mount, 1.6 mm × 2.9 mm footprint with 0.95 mm height. Pin 1 is N/C (no connect), pin 2 is GND, pin 3 is EN, pin 4 is VIN, pin 5 is VREF.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | N/C | No internal connection; must be left floating - not tied to GND or any signal |
| 2 | GND | Reference ground return path; requires low-impedance PCB trace to minimize noise coupling |
| 3 | EN | Enable control input; pulled up internally (~2 µA); drives high (>65% VIN) to activate, low (<35% VIN) to enter 3 µA shutdown |
| 4 | VIN | Input supply; must exceed VREF + 400 mV (≥2.9 V for 2.5 V output) and remain ≤5.5 V |
| 5 | VREF | Precision 2.5 V output; stable with 0–10 µF capacitive loads; bypass capacitor recommended for transient immunity |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-free stability | Operates stably without mandatory output capacitor; eliminates BOM cost and layout area for basic use cases |
| Low dropout operation | Supports 2.5 V reference generation from 2.9 V input - critical for single-cell Li-ion and energy-harvesting systems |
| Enable-controlled shutdown | Reduces supply current from 60 µA to 3 µA, enabling duty-cycled precision sensing with microsecond wake-up |
| High load drive capability | Delivers up to 20 mA output current - sufficient to drive ADC reference inputs, op-amp bias networks, and small DACs directly |
| Thermal hysteresis control | 75 ppm max hysteresis ensures repeatable 2.5 V output after thermal cycling between −40°C and +125°C |
Applications
| Portable Data Acquisition | Automotive Sensor Conditioning |
|---|---|
Use Scenario: Handheld multimeter sampling 16-bit sigma-delta ADC with 2.5 V reference input. IC Role / Device Role / Timing Role: Precision voltage reference providing stable 2.5 V reference for ADC conversion accuracy. Use Value: ±0.1% initial accuracy and 75 ppm/°C tempco ensure <±0.01% full-scale error across operating temperature, meeting Class II meter specs. |
Use Scenario: Tire pressure monitoring system (TPMS) ECU measuring piezoresistive sensor bridge output. IC Role / Device Role / Timing Role: Reference source for ratiometric measurement of bridge voltage against 2.5 V基准. Use Value: AEC-Q100 Grade 1 qualification and −40°C to +125°C operation guarantee reliability in under-hood environments. |
| Battery-Powered IoT Node | Industrial Process Controller |
Use Scenario: LPWAN node with ultra-low-power MCU and 12-bit SAR ADC monitoring environmental sensors. IC Role / Device Role / Timing Role: Micropower reference enabling sleep-mode current <1 µA while retaining fast wake-up reference stability. Use Value: 3 µA shutdown current and 33.2 µs turn-on time allow reference activation only during ADC sampling, minimizing average power. |
Use Scenario: 4–20 mA transmitter module converting analog sensor output using 16-bit DAC with precision reference. IC Role / Device Role / Timing Role: Stable 2.5 V reference for DAC full-scale setting and loop calibration. Use Value: Long-term stability of 50 ppm/1000 hrs ensures calibration validity over 6-month maintenance cycles without field recalibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| REF3025AIDBZR | 2.5 V, ±0.2% initial accuracy, 100 ppm/°C, 50 µA IQ, SOT-23-5 | Lower accuracy and higher tempco than LM4128AMFX-2.5; no enable pin | Select when enable functionality is unnecessary and cost sensitivity outweighs 0.1% accuracy requirement |
| ADR3425ARJZ-R7 | 2.5 V, ±0.1% initial accuracy, 50 ppm/°C, 120 µA IQ, SOT-23-5 | Superior tempco but 2× higher quiescent current; no enable pin | Select when lowest possible thermal drift is critical and system can accommodate higher idle current |
Compared with REF3025AIDBZR and ADR3425ARJZ-R7, the LM4128AMFX-2.5 uniquely combines A-grade accuracy, ultra-low 60 µA supply current, and integrated enable control - making it optimal for battery-constrained, high-precision, and duty-cycled applications where both performance and power efficiency are non-negotiable.
Availability
LM4128AMFX-2.5 is available at Aetrix Electronics and suitable for portable instrumentation, automotive sensor modules, and industrial process controllers requiring stable component supply with guaranteed long-term availability.
Supply support for LM4128AMFX-2.5 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
National Semiconductor was a U.S.-based analog semiconductor company acquired by Texas Instruments in 2011; its precision reference portfolio remains widely deployed in industrial and automotive systems.
The LM4128 series was designed specifically for space-constrained, battery-powered applications demanding high initial accuracy, low drift, and micropower operation - targeting instrumentation, portable test gear, and automotive ECUs.
FAQ
What is the maximum input voltage for LM4128AMFX-2.5?
The LM4128AMFX-2.5 supports a maximum input voltage of 5.5 V. Operation above this level risks damage per Absolute Maximum Ratings. For reliable function, VIN must also stay ≥ VREF + 400 mV (i.e., ≥2.9 V for the 2.5 V output), ensuring adequate headroom for dropout across load and temperature.
Does LM4128AMFX-2.5 require an input capacitor?
Yes - an input capacitor (CIN) is required for stable operation. Per datasheet Application Information, CIN must be ≥ COUT; if no output capacitor is used, CIN must be ≥0.1 µF. Ceramic X5R/X7R types are recommended, and mounting close to the device minimizes parasitic inductance.
Can LM4128AMFX-2.5 drive a 10 µF capacitive load?
Yes - the LM4128AMFX-2.5 is explicitly characterized for stability with capacitive loads up to 10 µF. This eliminates need for isolation resistors in many applications, simplifying design and improving transient response when driving ADC reference inputs or op-amp bias networks.
What is the output noise specification for LM4128AMFX-2.5?
The LM4128AMFX-2.5 delivers 275 µVPP (peak-to-peak) output noise over the 0.1 Hz to 10 Hz bandwidth. This low noise floor supports high-resolution data acquisition systems, including 16-bit SAR and sigma-delta ADCs, without requiring external filtering in most implementations.
Is LM4128AMFX-2.5 qualified for automotive applications?
No - LM4128AMFX-2.5 is the commercial-grade variant. Automotive-qualified equivalents are designated with "Q" suffixes (e.g., LM4128AQ1MFX2.5), which undergo AEC-Q100 Grade 1 qualification and are manufactured on an enhanced automotive production flow. LM4128AMFX-2.5 is rated for −40°C to +125°C but lacks formal automotive qualification.
LM4128AMFX-2.5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- SC-74A, SOT-753
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Reference Type:
- Series
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- ±0.1%
- Temperature Coefficient:
- 75ppm/°C
- Noise - 0.1Hz to 10Hz:
- 275µVp-p
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- 2.9V ~ 5.5V
- Current - Supply:
- 100µA
- Current - Cathode:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM4128AMFX-2.5 FAQ
1.How can I place an order for LM4128AMFX-2.5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM4128AMFX-2.5 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 LM4128AMFX-2.5 reliable?
The price and inventory of LM4128AMFX-2.5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM4128AMFX-2.5 is usually 5 days.
3.What payment methods are accepted for LM4128AMFX-2.5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM4128AMFX-2.5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM4128AMFX-2.5?
LM4128AMFX-2.5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM4128AMFX-2.5 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 LM4128AMFX-2.5?
For technical support, including LM4128AMFX-2.5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM4128AMFX-2.5 requirements.
6.How does Aetrix verify that LM4128AMFX-2.5 is sourced from the original manufacturer or authorized distributors?
All LM4128AMFX-2.5 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 LM4128AMFX-2.5 meets industry standards.
7.What is the process for return or replacement of LM4128AMFX-2.5?
All LM4128AMFX-2.5 units undergo pre-shipment inspection (PSI). If there is an issue with LM4128AMFX-2.5, 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 LM4128AMFX-2.5 part is unused and in its original packaging.
Return procedure for LM4128AMFX-2.5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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