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Texas Instruments LM4128CMFX-4.1
- Part No.:
- LM4128CMFX-4.1
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM4128CMFX-4.1.pdf
- Description:
- IC VREF SERIES 0.5% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
LM4128CMFX-4.1 from Texas Instruments (formerly National Semiconductor) is a precision micropower series voltage reference in SOT-23-5 package, delivering 4.096 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 high-resolution ADC/DAC biasing in portable instrumentation and battery-powered data acquisition systems.
For engineers reviewing the LM4128CMFX-4.1 datasheet, LM4128CMFX-4.1 pinout, LM4128CMFX-4.1 application, or LM4128CMFX-4.1 equivalent, key selection considerations include dropout voltage (≤400 mV at 10 mA), line regulation (100 ppm/V), load regulation (25–120 ppm/mA), 0.1–10 Hz noise (350 µVPP), and thermal hysteresis (75 ppm) over −40°C to +125°C.
Technical Context
The LM4128CMFX-4.1 uses a band-gap–derived reference core optimized for low-power, high-stability operation in space-constrained designs. Its series architecture eliminates need for external stabilization capacitors while maintaining stability with capacitive loads up to 10 µF - enabling direct drive of SAR ADC reference inputs without added buffering.
It integrates an enable control path with 35% VIN low-level threshold and 65% VIN high-level threshold, allowing seamless integration into power-gated subsystems. The device operates from VIN = VREF + 400 mV to 5.5 V, supporting single-supply 5 V or Li-ion–based systems without LDO pre-regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 4.096 V nominal - matches 12-bit full-scale ADC reference for exact binary scaling (e.g., 4096 LSB = 4.096 V). |
| Initial Accuracy | ±0.5% at 25°C - corresponds to ±20.5 mV absolute error, sufficient for 10-bit system accuracy without calibration. |
| Tempco | 100 ppm/°C max - contributes ≤±12.3 mV drift over −40°C to +125°C, critical for uncalibrated industrial sensor front-ends. |
| Quiescent Current | 60 µA - enables >1-year battery life in 10 µA sleep-cycle IoT sensors using periodic wake-up sampling. |
| Dropout Voltage | 400 mV at 10 mA - allows operation from 4.5 V supply in automotive body-control modules with minimal headroom loss. |
| Shutdown Current | 3 µA - reduces standby power by 20× vs active mode, essential for energy-harvesting applications. |
| Output Noise | 350 µVPP (0.1–10 Hz) - limits effective resolution to ~14.5 bits in precision weigh-scale amplifiers. |
Pinout & Package
SOT-23-5 package (NS package number MF05A), 1.6 mm × 2.8 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 floating; internal disconnect prevents parasitic coupling or leakage paths. |
| 2 | GND | Analog ground reference - requires low-impedance connection to clean AGND plane to minimize noise injection into reference node. |
| 3 | EN | Active-high enable input - driven high (>65% VIN) to activate; pulled low (<35% VIN) or grounded to enter 3 µA shutdown state. |
| 4 | VIN | Unregulated input supply - must exceed VREF + 400 mV; accepts up to 5.5 V; bypassed externally with ≥0.1 µF ceramic capacitor. |
| 5 | VREF | Precision 4.096 V output - drives ADC reference pins, DAC bias networks, or comparator thresholds; stable with 0–10 µF capacitive loads. |
Key Features
| Feature | Design Value |
|---|---|
| Enable-controlled shutdown | Reduces supply current from 60 µA to 3 µA - enables duty-cycled operation in battery-powered DAQ nodes. |
| Capacitor-free stability | Eliminates mandatory output capacitor - simplifies layout and avoids ESR-related instability in high-reliability medical sensors. |
| Low dropout voltage | 400 mV at 10 mA - permits direct use after 3.3 V LDOs or coin-cell sources without additional regulation stages. |
| Indefinite short-circuit protection | Limits output current to 75 mA - protects device during PCB test probe faults or accidental VREF-to-GND shorts. |
| Thermal hysteresis | 75 ppm - ensures repeatable 4.096 V output after thermal cycling in automotive under-hood environments. |
Applications
| Portable Data Loggers | Industrial PLC Analog Inputs |
|---|---|
Use Scenario: Battery-operated environmental sensor node recording temperature, humidity, and pressure at 1-minute intervals. IC Role / Device Role / Timing Role: Provides stable 4.096 V reference for 16-bit sigma-delta ADC converting sensor signals with <1 LSB drift over temperature. Use Value: 60 µA quiescent current extends CR2032 battery life beyond 2 years; enable pin synchronizes reference activation with ADC conversion window. |
Use Scenario: Modular I/O card in programmable logic controller accepting 4–20 mA current-loop field signals. IC Role / Device Role / Timing Role: Supplies precision reference for 24-bit ADC measuring shunt voltage with 0.01% total unadjusted error (TUE). Use Value: 100 ppm/°C tempco ensures <0.05% gain error across −25°C to +70°C cabinet range; SOT-23-5 footprint saves board space in dense backplane modules. |
| Medical Patient Monitors | Automotive Battery Management Systems |
Use Scenario: Portable ECG module digitizing biopotential signals with 1 µV resolution and DC-coupled baseline stability. IC Role / Device Role / Timing Role: Reference source for low-noise instrumentation amplifier and 12-bit successive-approximation ADC. Use Value: 350 µVPP (0.1–10 Hz) noise enables sub-microvolt signal integrity; long-term stability of 50 ppm/1000 hrs maintains calibration between service intervals. |
Use Scenario: Cell-voltage monitoring IC in 12S lithium-ion pack, requiring accurate 4.096 V reference for 16-bit ADC per cell. IC Role / Device Role / Timing Role: Precision reference for isolated analog front-end measuring individual cell voltages in BMS stack. Use Value: −40°C to +125°C operating range supports under-hood deployment; 400 mV dropout enables direct use from 4.5 V auxiliary rail without extra regulator. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| REF3040AIDBZR | 4.096 V, ±0.2% initial accuracy, 50 ppm/°C, 50 µA IQ, SOT-23-3 (no EN pin) | Higher accuracy and lower tempco, but lacks enable control and uses 3-pin package - requires external logic for power gating. | Select when highest stability is required and shutdown control is implemented elsewhere in system. |
| MAX6029AEUR+T | 4.096 V, ±0.2% initial accuracy, 75 ppm/°C, 35 µA IQ, SOT-23-5 with EN pin | Lower quiescent current and better tempco than LM4128CMFX-4.1, but rated only to +85°C ambient (not +125°C junction). | Select for commercial-grade portable equipment where extended temperature range is not required. |
Compared with REF3040AIDBZR and MAX6029AEUR+T, the LM4128CMFX-4.1 offers the widest temperature range (−40°C to +125°C) and integrated enable functionality in a 5-pin SOT-23, making it uniquely suited for automotive and industrial applications demanding both ruggedness and power-state control.
Availability
LM4128CMFX-4.1 is available at Aetrix Electronics and suitable for portable instrumentation, industrial PLC analog inputs, medical patient monitors, and automotive battery management systems requiring stable component supply with guaranteed long-term availability.
Supply support for LM4128CMFX-4.1 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, micropower precision applications - emphasizing low dropout, capacitor-free stability, and grade-scalable accuracy for instrumentation, test equipment, and automotive subsystems.
FAQ
What is the maximum load current supported by the LM4128CMFX-4.1?
The LM4128CMFX-4.1 supports up to 20 mA output current while maintaining specified accuracy and regulation. This capability allows direct driving of multiple ADC reference inputs or moderate-current bias networks without external buffers. At 20 mA load, dropout remains within 400 mV, and load regulation is bounded at 120 ppm/mA - ensuring predictable performance in multi-channel data acquisition systems.
Does the LM4128CMFX-4.1 require an input capacitor?
Yes, the LM4128CMFX-4.1 requires a minimum 0.1 µF ceramic input capacitor (X5R/X7R) for stable operation. When an output capacitor is used, the input capacitor must be ≥ its value. Larger input capacitors (e.g., 4.7–22 µF) reduce output noise and startup overshoot. This requirement is explicitly stated in the Application Information section and verified across all operating conditions in the datasheet.
What is the function of Pin 1 (N/C) on the LM4128CMFX-4.1?
Pin 1 of the LM4128CMFX-4.1 is a no-connect (N/C) terminal - it is internally unconnected and must be left floating. Routing traces to or placing solder on Pin 1 may introduce parasitic capacitance or leakage paths that degrade reference accuracy or long-term stability. The datasheet explicitly states "No connect pin, leave floating" in the Pin Descriptions table.
Can the LM4128CMFX-4.1 operate from a 3.3 V supply?
No, the LM4128CMFX-4.1 cannot operate from a 3.3 V supply. Its minimum input voltage is VREF + 400 mV = 4.496 V. Operation requires VIN ≥ 4.5 V - typically supplied from a 5 V rail or regulated 4.8–5.5 V source. Attempting to power it from 3.3 V will result in output collapse and undefined behavior, as confirmed by the Absolute Maximum Ratings and Operating Ratings sections.
How does the enable pin (Pin 3) interface with standard logic levels?
The enable pin (Pin 3) of the LM4128CMFX-4.1 uses ratio-based thresholds: VIL ≤ 35% VIN (disable) and VIH ≥ 65% VIN (enable). For a 5 V supply, this translates to <1.75 V (low) and >3.25 V (high). It is compatible with 3.3 V CMOS outputs when VIN = 5 V, but not directly with 1.8 V logic without level shifting - a detail confirmed in the Electrical Characteristics table under VIL/VIH parameters.
LM4128CMFX-4.1 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):
- 4.096V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- ±0.5%
- Temperature Coefficient:
- 100ppm/°C
- Noise - 0.1Hz to 10Hz:
- 350µVp-p
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- 4.496V ~ 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-4.1 FAQ
1.How can I place an order for LM4128CMFX-4.1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM4128CMFX-4.1 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-4.1 reliable?
The price and inventory of LM4128CMFX-4.1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM4128CMFX-4.1 is usually 5 days.
3.What payment methods are accepted for LM4128CMFX-4.1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM4128CMFX-4.1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM4128CMFX-4.1?
LM4128CMFX-4.1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM4128CMFX-4.1 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-4.1?
For technical support, including LM4128CMFX-4.1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM4128CMFX-4.1 requirements.
6.How does Aetrix verify that LM4128CMFX-4.1 is sourced from the original manufacturer or authorized distributors?
All LM4128CMFX-4.1 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-4.1 meets industry standards.
7.What is the process for return or replacement of LM4128CMFX-4.1?
All LM4128CMFX-4.1 units undergo pre-shipment inspection (PSI). If there is an issue with LM4128CMFX-4.1, 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-4.1 part is unused and in its original packaging.
Return procedure for LM4128CMFX-4.1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM4128CMFX-4.1 Tags
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AZ431LANTR-G1
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