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Texas Instruments LM4128CMFX-1.8
- Part No.:
- LM4128CMFX-1.8
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM4128CMFX-1.8.pdf
- Description:
- IC VREF SERIES 0.5% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,455
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Product details
Overview
LM4128CMFX-1.8 from Texas Instruments (formerly National Semiconductor) is a precision micropower series voltage reference in SOT-23-5 package, delivering 1.8 V output with ±0.5% initial accuracy, 100 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 battery-powered instrumentation and portable data acquisition systems.
For engineers reviewing the LM4128CMFX-1.8 datasheet, LM4128CMFX-1.8 pinout, LM4128CMFX-1.8 application, or LM4128CMFX-1.8 equivalent, key selection considerations include dropout voltage (400 mV at 10 mA), line regulation (30 ppm/V), load regulation (25–120 ppm/mA), output noise (170 µVPP, 0.1–10 Hz), and thermal hysteresis (75 ppm).
Technical Context
The LM4128CMFX-1.8 uses a band-gap–derived reference core optimized for low-power operation and capacitive-load stability without external compensation. Its series architecture eliminates idle current waste typical of shunt references, enabling efficient use in low-IQ systems.
It integrates an enable input (EN) that controls internal biasing, allowing transition between active mode (60 µA IQ) and shutdown mode (3–7 µA). The device maintains regulation over −40°C to +125°C junction temperature and accepts input voltages from (VREF + 400 mV) to 5.5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 1.8 V nominal; ±0.5% initial accuracy at 25°C ensures ≤9 mV absolute error in precision ADC/DAC biasing. |
| Temperature Coefficient | 100 ppm/°C max over −40°C to +125°C; contributes ≤21.6 ppm drift across full range, critical for industrial sensor calibration. |
| Quiescent Current | 60 µA typical; enables multi-year battery life in always-on monitoring nodes drawing <100 µA system current. |
| Dropout Voltage | 400 mV max at 10 mA load; allows operation from 2.2 V supply, compatible with single-cell Li-ion or two-cell alkaline systems. |
| Enable Function | EN pin supports 3–7 µA shutdown; reduces system standby power by >95% versus active mode-essential for duty-cycled IoT sensors. |
| Output Noise | 170 µVPP (0.1–10 Hz); meets 16-bit ADC reference noise budget (<200 µVPP) without filtering overhead. |
| Load Regulation | 25–120 ppm/mA; holds output within ±2.4 µV/mA variation-sufficient for stable biasing of op-amps and transimpedance amplifiers. |
Pinout & Package
SOT-23-5 package (NS package number MF05A), 1.6 mm × 2.9 mm footprint, 1.1 mm height, gull-wing leads. RoHS-compliant, rated for −40°C to +125°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | N/C | No-connect pin; must remain unconnected and floating-no routing or grounding permitted. |
| 2 | GND | Analog ground reference; requires low-impedance connection to main system ground plane to minimize noise coupling. |
| 3 | EN | Active-high enable input; driven ≥65% of VIN to activate; ≤35% of VIN to enter 3–7 µA shutdown state. |
| 4 | VIN | Input supply rail; must exceed VREF + 400 mV (≥2.2 V) and stay ≤5.5 V; bypassed with ≥0.1 µF ceramic capacitor. |
| 5 | VREF | Precision 1.8 V output; capable of sourcing up to 20 mA; stable with capacitive loads ≤10 µF and ESR <1 Ω. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-free stability | Operates stably without output capacitor and supports up to 10 µF capacitive load-eliminates need for external compensation network. |
| Micropower operation | 60 µA supply current enables integration into sub-100 µA energy-harvesting or coin-cell–powered systems. |
| Low dropout | 400 mV dropout at 10 mA allows direct regulation from low-voltage rails (e.g., 2.4 V LiFePO4 or 2.5 V LDO outputs). |
| Shutdown control | Enable pin reduces current to 3–7 µA-critical for extending battery life in wake-sleep architectures like wireless sensor nodes. |
| High-grade precision | C-grade accuracy (±0.5%) and tempco (100 ppm/°C) provide cost-optimized performance for industrial-grade measurement front-ends. |
Applications
| Portable Data Loggers | Battery-Powered Medical Sensors |
|---|---|
Use Scenario: Continuous 16-bit analog sensing of temperature, pressure, or ECG signals in handheld diagnostic devices powered by CR2032 or AAA batteries. IC Role / Device Role / Timing Role: Provides stable 1.8 V reference for SAR ADC and signal-chain op-amps, ensuring consistent LSB size across battery discharge cycle. Use Value: 60 µA IQ and 3 µA shutdown extend operational life beyond 2 years on a single coin cell; 170 µVPP noise avoids post-acquisition digital filtering. |
Use Scenario: Wearable pulse oximeter with optical front-end requiring precise DC biasing and low-noise analog signal conditioning. IC Role / Device Role / Timing Role: Supplies regulated 1.8 V to photodiode TIA and ADC reference inputs, maintaining SNR integrity during motion-induced supply ripple. Use Value: 400 mV dropout enables direct use of partially discharged 2.4 V Li-ion cells; 100 ppm/°C tempco ensures <0.2% gain drift across patient body temperature range. |
| Industrial Process Transmitters | Automotive Cabin Air Quality Modules |
Use Scenario: 4–20 mA loop-powered field transmitter measuring humidity or gas concentration in factory automation environments (−40°C to +85°C ambient). IC Role / Device Role / Timing Role: Precision 1.8 V reference for microcontroller ADC and analog output DAC, referenced against isolated 3.3 V system rail. Use Value: −40°C to +125°C junction rating and 75 ppm thermal hysteresis ensure repeatable calibration after thermal cycling; EN pin enables firmware-controlled self-test sequences. |
Use Scenario: In-cabin CO₂ and VOC sensor module operating from vehicle 12 V battery via buck converter (2.5 V output), subject to engine-start voltage dips. IC Role / Device Role / Timing Role: Supplies stable 1.8 V reference to NDIR detector amplifier and microcontroller ADC-immune to input ripple due to low line regulation (30 ppm/V). Use Value: Stable operation down to VIN = 2.2 V prevents reference collapse during cold-cranking events; AEC-Q100–qualified variants available (LM4128CQ1MFX-1.8). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| REF3018AIDBZR | 1.8 V, ±0.2% initial accuracy, 50 ppm/°C, 50 µA IQ, SOT-23-3 (no EN pin) | No enable function; fixed output; lower tempco but higher grade cost | Select when shutdown control is unnecessary and tighter long-term stability (50 ppm/°C) justifies premium pricing. |
| MAX6029AEUR+T | 1.8 V, ±0.5% initial accuracy, 75 ppm/°C, 35 µA IQ, SOT-23-3 (no EN) | Lacks enable pin; lower IQ but no shutdown mode; slightly better tempco than LM4128C | Choose for ultra-low-power designs where enable functionality is omitted and 75 ppm/°C tempco is required at C-grade cost point. |
Compared with REF3018AIDBZR and MAX6029AEUR+T, the LM4128CMFX-1.8 uniquely combines enable control, SOT-23-5 packaging, and C-grade precision at a balanced BOM cost-making it optimal for space-constrained, battery-gated systems needing both low IQ and active power management.
Availability
LM4128CMFX-1.8 is available at Aetrix Electronics and suitable for portable medical sensors, industrial data loggers, and automotive cabin air quality modules requiring stable component supply across extended production lifecycles.
Supply support for LM4128CMFX-1.8 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 acquired National Semiconductor in 2011 and maintains full product support, datasheets, and application engineering for legacy references including the LM4128 family.
The LM4128 series was designed specifically for space-constrained, battery-operated precision analog systems-emphasizing micropower operation, capacitive-load stability, and grade-flexible accuracy across industrial and automotive temperature ranges.
FAQ
What is the maximum input voltage for LM4128CMFX-1.8?
The LM4128CMFX-1.8 supports a maximum input voltage of 5.5 V. Operation above this level risks permanent damage per Absolute Maximum Ratings. For reliable regulation, VIN must be ≥2.2 V (VREF + 400 mV) and ≤5.5 V, with recommended input bypassing using ≥0.1 µF ceramic capacitor close to the VIN pin.
Does LM4128CMFX-1.8 require an output capacitor?
No, the LM4128CMFX-1.8 is stable without an output capacitor and is certified for capacitive loads up to 10 µF. An output capacitor (e.g., 1 µF ceramic) is optional but improves load transient response-especially when switching between light and heavy loads. Avoid arbitrarily large values (>10 µF) as they increase turn-on time and degrade transient behavior.
What is the shutdown current of LM4128CMFX-1.8?
The LM4128CMFX-1.8 draws 3–7 µA in shutdown mode when the EN pin is held low (≤35% of VIN). This ultra-low standby current enables multi-year battery life in intermittently active systems such as wireless sensor nodes or portable test equipment with sleep-wake cycles.
Can LM4128CMFX-1.8 drive a 20 mA load continuously?
Yes, the LM4128CMFX-1.8 is rated for continuous 20 mA output current. However, power dissipation must be verified: at 20 mA and 400 mV dropout, PD = 8 mW. With θJ-A = 220°C/W (SOT-23-5), junction temperature rise is <2°C-well within the −40°C to +125°C rating. Ensure adequate PCB copper for thermal relief in high-ambient environments.
Is LM4128CMFX-1.8 qualified for automotive applications?
The base LM4128CMFX-1.8 is not AEC-Q100 qualified. However, the pin-compatible automotive-grade variant LM4128CQ1MFX-1.8 is AEC-Q100 Grade 1 qualified (−40°C to +125°C) and manufactured on an automotive flow with enhanced defect detection. Use LM4128CQ1MFX-1.8 for under-hood or cabin modules requiring automotive reliability certification.
LM4128CMFX-1.8 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):
- 1.8V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- ±0.5%
- Temperature Coefficient:
- 100ppm/°C
- Noise - 0.1Hz to 10Hz:
- 170µVp-p
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- 2.2V ~ 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
LM4128CMFX-1.8 FAQ
1.How can I place an order for LM4128CMFX-1.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM4128CMFX-1.8 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 LM4128CMFX-1.8 reliable?
The price and inventory of LM4128CMFX-1.8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM4128CMFX-1.8 is usually 5 days.
3.What payment methods are accepted for LM4128CMFX-1.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM4128CMFX-1.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM4128CMFX-1.8?
LM4128CMFX-1.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM4128CMFX-1.8 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 LM4128CMFX-1.8?
For technical support, including LM4128CMFX-1.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM4128CMFX-1.8 requirements.
6.How does Aetrix verify that LM4128CMFX-1.8 is sourced from the original manufacturer or authorized distributors?
All LM4128CMFX-1.8 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 LM4128CMFX-1.8 meets industry standards.
7.What is the process for return or replacement of LM4128CMFX-1.8?
All LM4128CMFX-1.8 units undergo pre-shipment inspection (PSI). If there is an issue with LM4128CMFX-1.8, 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 LM4128CMFX-1.8 part is unused and in its original packaging.
Return procedure for LM4128CMFX-1.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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