Texas Instruments’ LM4041 – When a Zener Just Doesn’t Cut it

MicroCrystal RV-8803 – A Really Accurate RTC June 17, 2019- RTC chips traditionally were the domain of Maxim and NXP. Switzerland-based MicroCrystal recently made quite a buzz with its RV-8803, which offers simple integration, an I2C interface and extreme accuracy. Let us start out by looking at a system overview. Figure one shows how this I2C RTC is made up internally – interested observers note […]
Analog Devices’ LTM2887 – If a Digital Bus Needs Galvanic Isolation June 15, 2019- In theory, digital buses are intended to connect things to one another. Sadly, one sometimes wants but a logical connection – in many cases, galvanic isolation helps out. Should you ever feel like isolating very fast buses, definitely give the LTM2887 a chance. From a technical point of view, Linear Technologies attempt at entering the […]
AVAGO APDS-9008 or APDS-9005-020 – Keeping an Eye on Ambient Light June 14, 2019- Recent times saw quite a bit of interest for part numbers such as the APDS-9008 or APDS-9005-020 – they are a very interesting type of ambient light sensor. One of the oldest questions in regards to light sensors involves their spectral sensitivity. If a part is to output but one voltage level, the conversion between […]
STMicroelectronics’ LIS2DH12 – Low Power Motion Sensing June 12, 2019- Apple’s iPhone introduced gyroscopic sensors to a wider range – before that, accelerometers were not commonly found in consumer hardware. STM sells excellent parts which, however, get little media attention – time to take a look at the LIS2DH12. Integrating the part into your circuit as an MPU6500 alternative or MPU9500 alternative is not difficult. […]
Panasonic AMG8833 – FLIR for cheap June 7, 2019- FLIR made infrared thermal sensors cool – sadly, their parts are all but cheap (and suffer from export control problems). Panasonic’s Grid-EYE family is a low-resolution alternative which comes at significantly lower cost. From a technical point of view, Panasonic’s image sensor could not be simpler. We are looking at an 8×8 sensor with an […]
DipTronics DTS-62R-V – Small Switch, Very Big (and Very Cheap) June 5, 2019- When yours truly was but a lowly cadet, various US manufacturers produced (pricey but quite reliable) switches. Chinese vendors recently started to catch up – seeing the DTS-62R-V top our customer interest list shows that the run stage of the crawl-walk-run cycle is reached. DipTronics has been around the Asian switch market for ages, exhibiting […]

Finding a good voltage reference is as difficult as asking a cigar afficionado for the perfect smoke – the answer depends on the mood and the character of the individual queried. TI’s LM4041 series provides a “common sense” solution for all those not desperate for the highest accuracy.

From a technical point of view, the LM4041 is but a better zener diode available in various three- and five-terminal SMD housings. This means that the responsibility for current limitation falls solely in the hands of the user – directly connecting the part to a high, unregulated DC voltage rail leads to catastrophic failure. Instead, the simplest possible approach involves a shunt regulator as shown in figure one.

…The protection resistor limits the current flowing through the reference

TI provides an adjustable version of the LM4041, which works via a set of external feedback resistors. In that case, total accuracy depends on both the resistors and the LM4041 – a situation which can become interesting as thermal drift takes place.

In general, TI promises an original accuracy of their 0.1 or 0.2% as shipped, with detailed data given on the influence of temperature changes on system performance. Sadly, TI does not specify much in terms of long-time stability: the maximum information given in the datasheet claims a 125ppm change in voltage output over 1000 hours.
Nevertheless, the part – for sure – is interesting and should be at the back of your mind when working on data acquisition systems.