National Semiconductor LM4121 Precision Micropower Low Dropout Voltage Reference
Summary
This precision, micropower voltage reference provides highly accurate voltage output (1.25V or adjustable) for reliable power supply solutions. Designed for battery-powered and portable applications, it features ultra-low quiescent current, low dropout performance, and exceptional stability across vast temperature ranges (−40°C to +125°C). Ideal for industrial control, data acquisition systems, communications, and medical equipment requiring consistent performance from limited power sources.
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LM recision icropow er Low ropout Voltage eference
LM4121 Precision Micropower Low Dropout Voltage Reference General Description Features (LM4121-1.2)
The LM4121 is precision bandgap voltage reference avail- Small SOT23-5 package
able in fixed 1.25V and adjustable version with up to m A Low voltage operation current source and sink capability. High output voltage accuracy: 0.2%
This series reference operates with input voltages as low as Source and Sink current output: ±5 m A
1.8V and up to 12V consuming µA (Typ.) supply current. Supply current: µA Typ. In power down mode, device current drops to less than µA.
Low Temperature Coefficient: ppm/˚C
The LM4121 comes in two grades and Standard. The best Enable pin grade devices (A) have an initial accuracy of 0.2%, while the
Output voltages: 1.25V and Adjustable
standard have an initial accuracy of 0.5%, both with
Industrial temperature Range: −40˚C to +85˚C
tempco of 50ppm/˚C guaranteed from −40˚C to +125˚C.
(For extended temperature range, −40˚C to 125˚C,
The very low operating voltage, low supply current and
contact National Semiconductor)
power-down capability of the LM4121 makes this product an ideal choice for battery powered and portable applications.
Applications
The device performance is guaranteed over the industrial
Portable, battery powered equipment
temperature range (−40˚C to +85˚C), while certain specs are
Instrumentation and process control
guaranteed over the extended temperature range (−40˚C to
Automotive Industrial
+125˚C). Please contact National for full specifications over
the extended temperature range. The LM4121 is available in Test equipment
standard 5-pin SOT-23 package. Data acquisition systems
Precision regulators Battery chargers stations Communications Medical equipment
Connection Diagram
LM4121-1.2 Block Diagram
DS101291-2
Refer to the Ordering Information Table in this Data Sheet for Specific Part Number
SOT23-5 Surface Mount Package
DS101291-1
Resistors are removed on the LM4121-ADJ †LM4121-ADJ only
DS101291-35
National Semiconductor Corporation DS101291 www.national.com
Page Summary Contents For National Semiconductor LM4121 Precision Micropower Low Dropout Voltage Reference
Manual Details
| Brand | National |
|---|---|
| Pages | 16 |
| File Size | 436.50 KB |
| Published | May 29, 2026 |
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Frequently Asked Questions
What is the device's supply current draw during power-down mode?
The device current drops to less than 2 µA when operating in power-down mode.
How does the initial accuracy differ between Grade A and Standard grades?
Grade A devices guarantee an initial accuracy of 0.2%, while standard grade devices have an initial accuracy of 0.5%.
What is the minimum input voltage required for operation?
The reference operates with input voltages starting as low as 1.8V (when sourcing/sinking current).
Can this component withstand high temperatures?
Yes, it offers an extended temperature range of -40°C to +125°C, making it suitable for automotive and industrial applications.