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Texas Instruments LM4121AIM5-1.2/NOPB
- Part No.:
- LM4121AIM5-1.2/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM4121AIM5-1.2/NOPB.pdf
- Description:
- IC VREF SERIES 0.2% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:226
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Product details
Overview
LM4121AIM5-1.2/NOPB from Texas Instruments is a precision micropower low-dropout voltage reference IC delivering a fixed 1.25 V output with ±0.2% initial accuracy, 50 ppm/°C temperature coefficient, and ±5 mA source/sink capability in a 5-pin SOT-23 package. It operates from 1.8 V to 12 V input, draws only 160 µA typical supply current, and features an enable pin for power-down mode (<2 µA). It is used in portable instrumentation, battery-powered data acquisition, and precision regulators where stable, low-power reference voltage is critical.
For engineers reviewing the LM4121AIM5-1.2/NOPB datasheet, LM4121AIM5-1.2/NOPB pinout, LM4121AIM5-1.2/NOPB application, or LM4121AIM5-1.2/NOPB equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation insights, and two confirmed alternative parts with documented functional and application-level differences.
Technical Context
The LM4121AIM5-1.2/NOPB implements a bandgap-based voltage reference architecture with internal trimming for high initial accuracy and low thermal drift. Its enable pin controls a high-impedance analog switch that disconnects the reference core from the output stage, reducing quiescent current to <2 µA without compromising turn-on time or output stability.
It supports bidirectional load current (±5 mA), enabling use as both a sourcing and sinking reference in active feedback networks. The REF pin (Pin 1) is dedicated to the 1.25 V fixed-output variant and must remain unconnected - unlike the ADJ variant's Pin 1, which serves as the adjust node - ensuring correct biasing and noise performance per the 1.25 V option's electrical characteristics table.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.25 V ±0.2% (Grade A), enabling direct replacement of 1.25 V references in ADC/DAC biasing and LDO feedback without external resistors. |
| Tempco | 50 ppm/°C over −40°C to +125°C, ensuring ≤0.625 mV total drift across full industrial range - critical for 12-bit+ measurement accuracy. |
| Supply Current | 160 µA typical, allowing >1-year operation on a 200 mAh coin cell in always-on sensor nodes with periodic sampling. |
| Enable Threshold | VH = 1.5 V min, VL = 0.4 V max - compatible with 1.8 V and 3.3 V logic families without level-shifting. |
| Load Drive | ±5 mA sink/source capability permits direct driving of op-amp inputs, comparator references, or small MOSFET gates without buffering. |
| Noise (0.1–10 Hz) | 20 µVPP, supporting sub-16-bit resolution in precision weigh scales and medical front-ends where low-frequency noise dominates error budget. |
| Min Input Voltage | 1.8 V at 5 mA load, enabling operation from single Li-ion cells (2.7–4.2 V) or 2-cell alkaline (2.4–3.2 V) with margin for dropout. |
Pinout & Package
SOT-23-5 (DBV) package: 2.9 mm × 1.6 mm × 1.45 mm body, gull-wing leads, RoHS-compliant matte tin (Sn) finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (REF) | Reference Node | Internal 1.25 V tap - must be left unconnected for LM4121AIM5-1.2/NOPB; connecting it causes undefined behavior or damage. |
| Pin 2 (GND) | Ground Reference | Primary return path for load current and internal bias; requires low-impedance connection to minimize ground bounce in mixed-signal systems. |
| Pin 3 (EN) | Enable Control | Analog-input shutdown pin: ≥1.5 V enables output; ≤0.4 V disables output and reduces IQ to <2 µA - no external pull-up required if driven by CMOS. |
| Pin 4 (IN) | Positive Supply | Input voltage rail (1.8–12 V); accepts ceramic bypass capacitors ≥0.022 µF; no input cap needed unless line transients present. |
| Pin 5 (OUT) | Reference Output | Stable 1.25 V source/sink node; requires 0.022–0.047 µF ceramic capacitor (ESR 0.1–0.5 Ω) for guaranteed stability per TI application notes. |
Key Features
| Feature | Design Value |
|---|---|
| Micropower Operation | 160 µA typical supply current enables multi-year battery life in IoT edge sensors and portable meters. |
| Low Dropout | Operates down to 1.8 V input at full 5 mA load - supports direct regulation from single-cell batteries without pre-regulation. |
| Enable-Controlled Power-Down | Reduces supply current to <2 µA while preserving output settling time <10 µs upon re-enable - ideal for duty-cycled systems. |
| High Accuracy & Stability | ±0.2% initial tolerance + 50 ppm/°C tempco + 100 ppm long-term drift (1000 hrs) ensures calibration integrity in field-deployed equipment. |
| Robust Output Drive | ±5 mA bidirectional current capability eliminates need for external buffer op-amps in most 12-bit data converter reference designs. |
Applications
| Portable Medical Sensors | Battery-Powered Data Loggers |
|---|---|
Use Scenario: Continuous glucose monitor (CGM) with integrated ADC measuring electrochemical current at sub-µA levels. IC Role / Device Role / Timing Role: Provides ultra-stable 1.25 V reference for 16-bit SAR ADC, directly setting full-scale input range. Use Value: 20 µVPP low-frequency noise and 50 ppm/°C tempco ensure <0.01% measurement error across body temperature range (32–42°C). |
Use Scenario: Environmental sensor node logging temperature/humidity every 10 minutes using a microcontroller and sigma-delta ADC. IC Role / Device Role / Timing Role: Supplies precision reference to ADC during brief active periods; enabled only during conversion to minimize average current. Use Value: 160 µA operating current + <2 µA shutdown current extends CR2032 battery life beyond 3 years at 10-min sampling interval. |
| Industrial Process Transmitters | Automotive Cabin Sensors |
Use Scenario: 4–20 mA loop-powered pressure transmitter operating in harsh factory environments (−40°C to +85°C). IC Role / Device Role / Timing Role: Serves as primary voltage reference for DAC generating loop current setpoint; also biases signal conditioning amplifiers. Use Value: Guaranteed 50 ppm/°C tempco over −40°C to +125°C ensures <0.1% full-scale error across ambient extremes without recalibration. |
Use Scenario: Occupancy detection module in automotive HVAC control using IR proximity sensing and low-power MCU. IC Role / Device Role / Timing Role: Supplies reference to analog front-end amplifier and ADC measuring IR photodiode current. Use Value: 1.8 V minimum input voltage allows direct connection to vehicle's 2.8–3.3 V always-on rail, eliminating extra LDO and saving board space. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| REF3012AIDBZR | Fixed 1.2 V output, 50 ppm/°C tempco, 50 µA supply current, no enable pin. | Lacks power-down capability; lower supply current but incompatible where dynamic enable control is required. | Select when lowest possible quiescent current is prioritized and enable functionality is unnecessary. |
| MAX6012BEUR+T | Fixed 1.2 V output, 75 ppm/°C tempco, 35 µA supply current, no enable pin, ±3 mA drive. | Higher tempco and lower drive strength limit use in high-accuracy or high-load applications; smaller footprint (SOT23-3). | Select for ultra-low-power, space-constrained designs where ±0.5% total error budget accommodates higher tempco. |
Compared with REF3012AIDBZR and MAX6012BEUR+T, the LM4121AIM5-1.2/NOPB uniquely combines enable control, ±5 mA drive, and 1.25 V output in a standard SOT-23-5 - making it the only choice for applications requiring programmable reference activation and robust load handling without external circuitry.
Availability
LM4121AIM5-1.2/NOPB is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered data loggers, and industrial process transmitters requiring stable component supply and long-lifecycle support.
Supply support for LM4121AIM5-1.2/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 leader specializing in analog and embedded processing technologies, with decades of expertise in precision analog ICs and industrial-grade reliability.
The LM4121 series was designed specifically for battery-constrained, high-accuracy applications demanding micropower operation, low-voltage compatibility, and robust enable-controlled power management - targeting portable instrumentation and industrial sensing.
FAQ
What is the output voltage tolerance of the LM4121AIM5-1.2/NOPB over temperature?
The LM4121AIM5-1.2/NOPB has an initial accuracy of ±0.2% at 25°C and a guaranteed temperature coefficient of 50 ppm/°C over −40°C to +125°C. This results in a maximum total output variation of ±0.625 mV (±0.05%) across the full extended temperature range, confirmed in the Electrical Characteristics table for LM4121A-1.250V under boldface limits.
Can the LM4121AIM5-1.2/NOPB be used with a 1.8 V supply?
Yes - the LM4121AIM5-1.2/NOPB is specified to operate with input voltages as low as 1.8 V at 5 mA load, as stated in the Absolute Maximum Ratings and Electrical Characteristics tables. This makes it suitable for direct use with single Li-ion or 2-cell alkaline supplies without intermediate regulation.
Is the REF pin (Pin 1) required to be connected on the LM4121AIM5-1.2/NOPB?
No - the REF pin (Pin 1) on the LM4121AIM5-1.2/NOPB must be left unconnected. Per the PIN DESCRIPTIONS section, this pin is only used on the adjustable version (LM4121-ADJ); connecting it on the 1.25 V fixed version may cause malfunction or damage.
What is the typical startup time for the LM4121AIM5-1.2/NOPB after enabling?
The LM4121AIM5-1.2/NOPB achieves output regulation within 10 µs after the enable pin transitions from low to high, as shown in Figure 12 (Enable Response) of the datasheet. This fast wake-up supports high-efficiency duty-cycled systems such as wireless sensor nodes and portable test equipment.
Does the LM4121AIM5-1.2/NOPB require an output capacitor, and if so, what value?
Yes - the LM4121AIM5-1.2/NOPB requires a minimum 0.022 µF ceramic output capacitor for guaranteed stability, as specified in the APPLICATION HINTS section. Capacitors between 0.022 µF and 0.047 µF (ESR 0.1–0.5 Ω) are recommended; larger values up to 1 µF are permitted but require tantalum construction and additional compensation per Figure 34 guidance.
LM4121AIM5-1.2/NOPB 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):
- 1.25V
- Voltage - Output (Max):
- -
- Current - Output:
- 5 mA
- Tolerance:
- ±0.2%
- Temperature Coefficient:
- 50ppm/°C
- Noise - 0.1Hz to 10Hz:
- 20µVp-p
- Noise - 10Hz to 10kHz:
- 30µVrms
- Voltage - Input:
- 1.5V ~ 12V
- Current - Supply:
- 275µA
- Current - Cathode:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM4121AIM5-1.2/NOPB FAQ
1.How can I place an order for LM4121AIM5-1.2/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM4121AIM5-1.2/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 LM4121AIM5-1.2/NOPB reliable?
The price and inventory of LM4121AIM5-1.2/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM4121AIM5-1.2/NOPB is usually 5 days.
3.What payment methods are accepted for LM4121AIM5-1.2/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM4121AIM5-1.2/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM4121AIM5-1.2/NOPB?
LM4121AIM5-1.2/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM4121AIM5-1.2/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 LM4121AIM5-1.2/NOPB?
For technical support, including LM4121AIM5-1.2/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM4121AIM5-1.2/NOPB requirements.
6.How does Aetrix verify that LM4121AIM5-1.2/NOPB is sourced from the original manufacturer or authorized distributors?
All LM4121AIM5-1.2/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 LM4121AIM5-1.2/NOPB meets industry standards.
7.What is the process for return or replacement of LM4121AIM5-1.2/NOPB?
All LM4121AIM5-1.2/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM4121AIM5-1.2/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 LM4121AIM5-1.2/NOPB part is unused and in its original packaging.
Return procedure for LM4121AIM5-1.2/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM4121AIM5-1.2/NOPB Tags
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