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 […]
TLV7011 Series Comparator from Texas Instruments
Digital is not everything: in real life, one sometimes needs a comparator. Texas Instruments recently-introduced TLV70x1 series provide a cheap and space-conscious solution for this problem.
The traditional knee-jerk reaction to a problem requiring a comparator is a great indicator of your age; some will grab an LM324, others will go for an LM741. Both of these are opamps, who require quite a bit of external “diddling” before they can act as a reliable comparator. This not only increases BOM size and cost, but also wastes space on the board.
TI’s TLV70x1 family is a set of four ICs, each of which contain one comparator. The most outstanding attribute is the small size; the Extra Small Outline No-Lead (aka X2SON) package, described here, is but 0.8×0.8mm small. For prototyping, a classic SOT23 case is also available, which can be soldered by hand with some practice.
Generally, the parts are optimized to limit BOM changes. First of all, a supply voltage range of 1.6V to 5.5V means that the chip is very likely to “blend into” your environment. Benefit number two is an internal hysteresis to the – temperature dependent – tune of 4mV, thereby eliminating the need for a feedback resistor. One ambivalent aspect of the TLV70xx family is their capability to drive and sink insane amounts of current. Short-circuit values are in the range of 50mA, which means that most LEDs and even longer PCB traces can be driven directly. Of course, this also means that a bypass capacitor is recommended – the knife cuts both ways.
Greetings from the Kelly family
Traditionally, small part number deviations meant a change in the amount of chips in the case. This is not the case for the TLV family: the TLV7011 and 7031 have push-pull outputs, while the other ones use the open-drain principle. Furthermore, TLV7011 and TLV7021 use 5 Microamps of current and offer a propagation delay of 260ns, while the TLV7031 and TLV7041 need 335 Nanoamps at 3 Microseconds of propagation. Be aware that the TLV70xx series, being quite young, shows a tremendous price spread: as of this writing, quantity one prices range from 17 to more than 50 cents. Furthermore, finding datasheets can be difficult. But, as always, OEMsecrets to the rescue – simply follow the links in the table for more comparator goodness!