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Texas Instruments LM4128CMFX-3.3
- Part No.:
- LM4128CMFX-3.3
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM4128CMFX-3.3.pdf
- Description:
- IC VREF SERIES 0.5% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,745
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Product details
Overview
LM4128CMFX-3.3 from National Semiconductor is a precision micropower series voltage reference in SOT-23-5 package, delivering 3.3 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, supports up to 20 mA load, and operates across −40°C to +125°C - ideal for battery-powered instrumentation and portable data acquisition systems.
For engineers reviewing the LM4128CMFX-3.3 datasheet, LM4128CMFX-3.3 pinout, LM4128CMFX-3.3 application, or LM4128CMFX-3.3 equivalent, key selection considerations include dropout voltage (≤400 mV at 10 mA), line regulation (85 ppm/V), load regulation (25–120 ppm/mA), 310 µVPP (0.1–10 Hz) output noise, and compatibility with ceramic capacitive loads up to 10 µF without external stabilization.
Technical Context
The LM4128CMFX-3.3 uses a band-gap-derived reference core optimized for low-power, high-stability operation in space-constrained designs. Its series architecture eliminates idle current waste typical of shunt references, while internal compensation ensures stability with capacitive loads up to 10 µF - no external capacitor required on the output.
It integrates an enable input (EN) referenced to VIN, with logic thresholds at 35% and 65% of VIN, allowing direct microcontroller GPIO control. The device maintains regulation down to VIN = VREF + 400 mV and delivers precise 3.3 V output over full industrial temperature range with guaranteed long-term stability of 50 ppm/1000 hrs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3 V nominal, ±0.5% initial accuracy at 25°C - enables 10-bit ADC reference with ≤0.5 LSB error before trimming |
| Temperature Coefficient | 100 ppm/°C max (C grade) - limits drift to ±132 ppm over −40°C to +125°C (±0.43 mV) |
| Quiescent Current | 60 µA typical - supports >1-year battery life in 10 µA sleep-cycle sensor nodes |
| 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 3.7 V Li-ion cells down to 3.3 V under load |
| Output Noise | 310 µVPP (0.1–10 Hz) - suitable for 12-bit SAR ADCs without additional filtering |
| Line Regulation | 85 ppm/V - introduces ≤280 µV change per 1 V input variation, critical for unregulated supply rails |
| Load Regulation | 25–120 ppm/mA - ensures <±0.4 mV shift from 0 to 20 mA load, supporting dynamic sensor biasing |
Pinout & Package
SOT-23-5 package (NS MF05A), 1.6 mm × 2.9 mm footprint, surface-mount, lead-free compatible.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | N/C | No-connect pin; must remain floating - internal disconnect prevents parasitic coupling |
| 2 | GND | Analog ground reference; requires low-impedance PCB connection to minimize noise injection |
| 3 | EN | Enable input referenced to VIN; asserts high (>65% VIN) to activate, low (<35% VIN) to enter 3 µA shutdown |
| 4 | VIN | Input supply rail; must exceed VREF + 400 mV (≥3.7 V for 3.3 V output) and stay ≤5.5 V |
| 5 | VREF | Precision 3.3 V output; stable with 0–10 µF ceramic capacitive loads; bypass cap recommended for transient immunity |
Key Features
| Feature | Design Value |
|---|---|
| Enable-controlled shutdown | Reduces supply current from 60 µA to 3 µA - extends battery life in intermittent-sampling applications |
| Capacitor-free stability | Stable with 0–10 µF ceramic output capacitance - eliminates BOM cost and layout area for external compensation |
| Micropower operation | 60 µA quiescent current - enables use in energy-harvesting and ultra-low-power IoT endpoints |
| Low thermal hysteresis | 75 ppm over −40°C to +125°C cycling - preserves calibration integrity in thermally cycled industrial enclosures |
| Indefinite short-circuit protection | Limits output current to 75 mA - protects device during board-level fault conditions without latch-up |
Applications
| Portable Data Loggers | Industrial Sensor Transmitters |
|---|---|
Use Scenario: Battery-powered environmental monitors logging temperature, humidity, and pressure at 1-minute intervals. IC Role / Device Role / Timing Role: Precision 3.3 V reference for 12-bit ADC and analog front-end conditioning. Use Value: ±0.5% initial accuracy and 100 ppm/°C tempco ensure <±1.5°C temperature measurement error over full operating range without field recalibration. |
Use Scenario: 4–20 mA loop-powered pressure transmitter in oil & gas pipeline monitoring. IC Role / Device Role / Timing Role: Stable excitation reference for bridge sensors and ADC reference in isolated signal chain. Use Value: 60 µA supply current minimizes loop burden; 400 mV dropout enables operation from minimal loop headroom (≤3.7 V). |
| Medical Point-of-Care Devices | Automotive Body Control Modules |
Use Scenario: Handheld blood glucose meters requiring FDA-grade accuracy and multi-year shelf life. IC Role / Device Role / Timing Role: Primary voltage reference for biosensor signal conditioning and ADC conversion. Use Value: 50 ppm long-term stability over 1000 hrs ensures calibration retention between factory test and end-user deployment. |
Use Scenario: In-vehicle cabin temperature and occupancy sensing using thermistors and IR sensors. IC Role / Device Role / Timing Role: Reference source for ratiometric sensor measurements and microcontroller ADC. Use Value: −40°C to +125°C operation and AEC-Q100-compliant CQ variants support under-hood and dashboard mounting without derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| REF3033AIDBZR | 3.3 V, ±0.2% initial accuracy, 50 ppm/°C, 50 µA IQ, SOT-23-3 - no enable pin, lower tempco, higher accuracy grade | Requires external enable circuitry if shutdown needed; better suited for fixed-supply, high-accuracy metrology | Select REF3033AIDBZR when tempco <50 ppm/°C and no enable function are prioritized over micropower shutdown |
| MAX6033AEUR+T | 3.3 V, ±0.5% initial accuracy, 75 ppm/°C, 35 µA IQ, SOT-23-5 - includes enable, lower IQ, tighter tempco than LM4128CMFX-3.3 | Superior power efficiency and stability; pin-compatible but requires validation of EN threshold compatibility | Select MAX6033AEUR+T when reducing system standby power below 3 µA and improving thermal drift are design goals |
Compared with REF3033AIDBZR and MAX6033AEUR+T, the LM4128CMFX-3.3 offers the lowest cost per unit and widest input voltage margin (VIN up to 5.5 V), making it optimal for cost-sensitive, wide-input industrial sensors where moderate tempco is acceptable.
Availability
LM4128CMFX-3.3 is available at Aetrix Electronics and suitable for portable instrumentation, industrial sensor transmitters, and automotive body electronics requiring stable component supply with consistent parametric performance across production lots.
Supply support for LM4128CMFX-3.3 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 semiconductor company specializing in analog and mixed-signal ICs, acquired by Texas Instruments in 2011; its legacy precision reference portfolio remains widely deployed in industrial and automotive systems.
The LM4128 series was designed as a micropower, easy-to-use series voltage reference family targeting space-constrained, battery-operated, and high-reliability applications - emphasizing low dropout, capacitor-free stability, and grade-flexible accuracy.
FAQ
What is the maximum input voltage for the LM4128CMFX-3.3?
The LM4128CMFX-3.3 supports a maximum input voltage of 5.5 V. Operation above this level risks permanent damage, as specified in Absolute Maximum Ratings. For reliable regulation, VIN must also remain ≥ VREF + 400 mV (i.e., ≥3.7 V) across all load and temperature conditions. Exceeding 5.5 V violates absolute maximum limits and may trigger internal protection or cause irreversible failure.
Does the LM4128CMFX-3.3 require an input capacitor?
Yes - the LM4128CMFX-3.3 requires a minimum 0.1 µF ceramic input capacitor (X5R/X7R) for stable operation. When an output capacitor is used, CIN must be ≥ COUT. This capacitor suppresses supply noise and prevents oscillation during startup or load transients. Omitting CIN risks instability, especially with noisy or high-impedance sources, and is explicitly prohibited in the Application Information section.
Can the LM4128CMFX-3.3 drive a 10 µF capacitive load?
Yes - the LM4128CMFX-3.3 is explicitly characterized and guaranteed stable with capacitive loads up to 10 µF, including low-ESR ceramic types. This eliminates the need for external isolation resistors or compensation networks. However, larger output capacitance increases turn-on time (e.g., 78.8 µs for 10 µF vs. 33.2 µs for 1 µF) and may degrade load transient response speed.
What is the shutdown current of the LM4128CMFX-3.3?
The LM4128CMFX-3.3 draws ≤7 µA (typical 3 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 wake-on-event architectures. The EN pin has an internal pull-up (~2 µA), so leaving it open defaults to enabled state - intentional shutdown requires active low drive or grounding via MCU GPIO.
Is the LM4128CMFX-3.3 qualified for automotive applications?
The LM4128CMFX-3.3 is not automotive-qualified; only LM4128CQ1MFX-3.3 (with "Q" suffix) meets AEC-Q100 Grade 1 requirements. The "C" grade indicates 0.5% initial accuracy and 100 ppm/°C tempco, but lacks automotive process flow, enhanced testing, and extended reliability documentation. For automotive use, specify LM4128CQ1MFX-3.3 or equivalent qualified variants.
LM4128CMFX-3.3 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):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- ±0.5%
- Temperature Coefficient:
- 100ppm/°C
- Noise - 0.1Hz to 10Hz:
- 310µVp-p
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- 3.7V ~ 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-3.3 FAQ
1.How can I place an order for LM4128CMFX-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM4128CMFX-3.3 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-3.3 reliable?
The price and inventory of LM4128CMFX-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM4128CMFX-3.3 is usually 5 days.
3.What payment methods are accepted for LM4128CMFX-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM4128CMFX-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM4128CMFX-3.3?
LM4128CMFX-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM4128CMFX-3.3 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-3.3?
For technical support, including LM4128CMFX-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM4128CMFX-3.3 requirements.
6.How does Aetrix verify that LM4128CMFX-3.3 is sourced from the original manufacturer or authorized distributors?
All LM4128CMFX-3.3 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-3.3 meets industry standards.
7.What is the process for return or replacement of LM4128CMFX-3.3?
All LM4128CMFX-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM4128CMFX-3.3, 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-3.3 part is unused and in its original packaging.
Return procedure for LM4128CMFX-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM4128CMFX-3.3 Tags
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