EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: Smokey on July 09, 2023, 09:04:16 am
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Find an interesting/useful part?
Think other people will also think it's interesting and/or useful?
Post it here.
Chip of the day!
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LM7705 Low-Noise Negative Bias Generator
https://www.ti.com/lit/ds/symlink/lm7705.pdf (https://www.ti.com/lit/ds/symlink/lm7705.pdf)
3V-5.25V Input
-0.23V Out at about 20mA
Good for those "RRIO" opamps if you actually need actual RRIO
Only $0.86 in 1s at Digikey
https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262 (https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262)
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I like OPA991 family (or the 992 upgrade). Quite a universal opamp.
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LM7705 Low-Noise Negative Bias Generator
https://www.ti.com/lit/ds/symlink/lm7705.pdf (https://www.ti.com/lit/ds/symlink/lm7705.pdf)
3V-5.25V Input
-0.23V Out at about 20mA
Good for those "RRIO" opamps if you actually need actual RRIO
Only $0.86 in 1s at Digikey
https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262 (https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262)
I like this one LM27762
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LM7705 Low-Noise Negative Bias Generator
https://www.ti.com/lit/ds/symlink/lm7705.pdf (https://www.ti.com/lit/ds/symlink/lm7705.pdf)
3V-5.25V Input
-0.23V Out at about 20mA
Good for those "RRIO" opamps if you actually need actual RRIO
Only $0.86 in 1s at Digikey
https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262 (https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262)
I like this one LM27762
Nice. That must be a new part. it's not in webbench yet.
One thing to watch out for is the positive output is just LDO down regulated from the input voltage, and the negative output is inverted from the input voltage and then LDO regulated. So you can't have +/-5V from a 3.3V input (even though it sort of looks that way from the banner specs).
If you actually need +/-5V from something like 3.3V input, this would work:
TPS65133
https://www.digikey.com/en/products/detail/texas-instruments/TPS65133DPDR/ (https://www.digikey.com/en/products/detail/texas-instruments/TPS65133DPDR/)
https://www.ti.com/lit/ds/symlink/tps65133.pdf (https://www.ti.com/lit/ds/symlink/tps65133.pdf)
QTY UNIT PRICE
1 $2.56
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I have several favourites, but the latest is the TI LM2660 (and LM2662). Not new, but to me they are.
+/-5 V from a single USB +5 V input with just two caps.
I love it!
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LM7705 Low-Noise Negative Bias Generator
https://www.ti.com/lit/ds/symlink/lm7705.pdf (https://www.ti.com/lit/ds/symlink/lm7705.pdf)
3V-5.25V Input
-0.23V Out at about 20mA
Good for those "RRIO" opamps if you actually need actual RRIO
Only $0.86 in 1s at Digikey
https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262 (https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262)
Um all that work for -0.23V? I am confused... The ICL7660 came out in 1980 and gave more, like -5V.
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LM7705 Low-Noise Negative Bias Generator
https://www.ti.com/lit/ds/symlink/lm7705.pdf (https://www.ti.com/lit/ds/symlink/lm7705.pdf)
3V-5.25V Input
-0.23V Out at about 20mA
Good for those "RRIO" opamps if you actually need actual RRIO
Only $0.86 in 1s at Digikey
https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262 (https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262)
Um all that work for -0.23V? I am confused... The ICL7660 came out in 1980 and gave more, like -5V.
There is a good answer to this one. Say you are using a single supply opamp like the TL900x series:
https://www.ti.com/lit/ds/symlink/tlv9002.pdf (https://www.ti.com/lit/ds/symlink/tlv9002.pdf)
It has a supply range up to 5.5V. If you are already running it from a +5V rail and all you need to actually output 0V, then you only have at most -0.5V that the negative rail can be. Since you only need about -20mV for the supposedly RRIO to be able to drive to 0V, the -0.23V of the LM7705 is more than enough to keep the opamp in the recommended operation range and drive 0V out.
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Magic little SOT23-6 dual complementary MOSFETS....pick your poison.
Typically pins 2 and 5 are Gate inputs which makes them a challenge to route but certainly not impossible, even with home etching. :phew:
Used them for power device gate drivers for years and some will warn you about shoot through but never had this issue.
I use them at logic levels as both a driver and level shifter for which they have been brilliant, even gate driving 200A IGBT's. :o
Gate charge is typically very low so with care driving them from 4000 IC's is simple.
Just one randomly selected:
https://www.farnell.com/datasheets/2300062.pdf (https://www.farnell.com/datasheets/2300062.pdf)
YMMV
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I like OPA991 family (or the 992 upgrade). Quite a universal opamp.
TI are iterating on "universal opamp" with others like OPAx828, or chopper OPAx189 lots of progress with analog capabilities still growing.
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LM7705 Low-Noise Negative Bias Generator
https://www.ti.com/lit/ds/symlink/lm7705.pdf (https://www.ti.com/lit/ds/symlink/lm7705.pdf)
3V-5.25V Input
-0.23V Out at about 20mA
Good for those "RRIO" opamps if you actually need actual RRIO
Only $0.86 in 1s at Digikey
https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262 (https://www.digikey.com/en/products/detail/texas-instruments/LM7705MMX-NOPB/2020262)
Um all that work for -0.23V? I am confused... The ICL7660 came out in 1980 and gave more, like -5V.
There is a good answer to this one. Say you are using a single supply opamp like the TL900x series:
https://www.ti.com/lit/ds/symlink/tlv9002.pdf (https://www.ti.com/lit/ds/symlink/tlv9002.pdf)
It has a supply range up to 5.5V. If you are already running it from a +5V rail and all you need to actually output 0V, then you only have at most -0.5V that the negative rail can be. Since you only need about -20mV for the supposedly RRIO to be able to drive to 0V, the -0.23V of the LM7705 is more than enough to keep the opamp in the recommended operation range and drive 0V out.
Yes, but it's not just about being enough for the job - it can achieve a significantly lower output ripple than the venerable ICL7660. Hence why it's marketed as "low noise".
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Currently I'm quite pleasantly surprised by the abilities of the ESP32-S3 chip. Only downside I've seen so far is the crappy ADC but other than that the software ecosystem is nice, well documented and the chip is very capable.
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Currently I'm quite pleasantly surprised by the abilities of the ESP32-S3 chip. Only downside I've seen so far is the crappy ADC but other than that the software ecosystem is nice, well documented and the chip is very capable.
You are right, the ESP32's in general are great other than the ADC. Super low cost and unlike other MCU suppliers (Microchip, TI and STM), I could get ESP32-C3's during COVID - and that is the reason I used them in two projects, albeit at risk. Also used an ESP32-S3-WROOM. You can calibrate the ADC's but still they are mediocre at best. No good for accurate analogue measurements, but I did use it on one project for a non-critical battery fuel gauge (could not get fuel gauge chips during COVID) and it was OK.
Espressif's BLE documentation is a dog's breakfast. Their hardware datasheets has ambiguity in them and is missing some detail that would be found in, say, TI and Analog Devices datasheets. The ecosystem is satisfactory but not great. Mind you I recently found a glaring pin-out error in Texas Instruments two year-old chip that no-one at TI had even picked up. The pinout list showed input pin for CAN bus data incorrectly described as a chip enable pin :wtf: TI's documentation QA is in trouble if such an error can exist for two years before they know about it. Overall Espressif does a reasonable job with their English documentation, considering it is a Chinese company.
No complaints though, because ESP32's got me out of a bind during COVID. Super low cost, which is good for high volume cost-sensitive projects. Plus I learnt to use a new MCU.
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Currently I'm quite pleasantly surprised by the abilities of the ESP32-S3 chip. Only downside I've seen so far is the crappy ADC but other than that the software ecosystem is nice, well documented and the chip is very capable.
You are right, the ESP32's in general are great other than the ADC. Super low cost and unlike other MCU suppliers (Microchip, TI and STM), I could get ESP32-C3's during COVID - and that is the reason I used them in two projects, albeit at risk. Also used an ESP32-S3-WROOM. You can calibrate the ADC's but still they are mediocre at best. No good for accurate analogue measurements, but I did use it on one project for a non-critical battery fuel gauge (could not get fuel gauge chips during COVID) and it was OK.
Espressif's BLE documentation is a dog's breakfast. Their hardware datasheets has ambiguity in them and is missing some detail that would be found in, say, TI and Analog Devices datasheets. The ecosystem is satisfactory but not great. Mind you I recently found a glaring pin-out error in Texas Instruments two year-old chip that no-one at TI had even picked up. The pinout list showed input pin for CAN bus data incorrectly described as a chip enable pin :wtf: TI's documentation QA is in trouble if such an error can exist for two years before they know about it. Overall Espressif does a reasonable job with their English documentation, considering it is a Chinese company.
No complaints though, because ESP32's got me out of a bind during COVID. Super low cost, which is good for high volume cost-sensitive projects. Plus I learnt to use a new MCU.
Which TI chip? I get it fixed.
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Find an interesting/useful part?
Think other people will also think it's interesting and/or useful?
Post it here.
Chip of the day!
No thanks, I want them to be available tomorrow ;D
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Find an interesting/useful part?
Think other people will also think it's interesting and/or useful?
Post it here.
Chip of the day!
You know, that's difficult. You can submit documentation feedback as shown in the attachment.
No thanks, I want them to be available tomorrow ;D
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I don't think documentation feedback will help with supply.
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Currently I'm quite pleasantly surprised by the abilities of the ESP32-S3 chip. Only downside I've seen so far is the crappy ADC but other than that the software ecosystem is nice, well documented and the chip is very capable.
You are right, the ESP32's in general are great other than the ADC. Super low cost and unlike other MCU suppliers (Microchip, TI and STM), I could get ESP32-C3's during COVID - and that is the reason I used them in two projects, albeit at risk. Also used an ESP32-S3-WROOM. You can calibrate the ADC's but still they are mediocre at best. No good for accurate analogue measurements, but I did use it on one project for a non-critical battery fuel gauge (could not get fuel gauge chips during COVID) and it was OK.
Espressif's BLE documentation is a dog's breakfast. Their hardware datasheets has ambiguity in them and is missing some detail that would be found in, say, TI and Analog Devices datasheets. The ecosystem is satisfactory but not great. Mind you I recently found a glaring pin-out error in Texas Instruments two year-old chip that no-one at TI had even picked up. The pinout list showed input pin for CAN bus data incorrectly described as a chip enable pin :wtf: TI's documentation QA is in trouble if such an error can exist for two years before they know about it. Overall Espressif does a reasonable job with their English documentation, considering it is a Chinese company.
No complaints though, because ESP32's got me out of a bind during COVID. Super low cost, which is good for high volume cost-sensitive projects. Plus I learnt to use a new MCU.
Which TI chip? I get it fixed.
The ISOW1044BDFMR. I did report it about 3 weeks ago, and to TI's credit they fixed it immediately and re-released the document. Pin 3 was listed as a chip enable when it was in fact a transmit data line.
I find it incredible no-one else has ever used this chip, of if they have, they are too busy or self-centred to report the error. Mind you, if I reported every bug in Altium, I'd never get any work done.
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I like OPA991 family (or the 992 upgrade). Quite a universal opamp.
TI are iterating on "universal opamp" with others like OPAx828, or chopper OPAx189 lots of progress with analog capabilities still growing.
Wow. Those are some impressive specs.. but at $6.30 in 1s... Not quite universal prices...
https://www.digikey.com/en/products/detail/texas-instruments/OPA4189IDR/15857137 (https://www.digikey.com/en/products/detail/texas-instruments/OPA4189IDR/15857137)
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The ISOW1044BDFMR. I did report it about 3 weeks ago, and to TI's credit they fixed it immediately and re-released the document. Pin 3 was listed as a chip enable when it was in fact a transmit data line.
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Datasheet from TI shows revision date of Dec 2021. Pinout for Pin3 shows it correctly as TXD. (Enable shows as Pin8).
https://www.ti.com/lit/ds/symlink/isow1044.pdf (https://www.ti.com/lit/ds/symlink/isow1044.pdf)
TI document control almost certainly is ISO9001, which makes revising a document but not bumping the revision essentially impossible.
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Currently I'm quite pleasantly surprised by the abilities of the ESP32-S3 chip. Only downside I've seen so far is the crappy ADC but other than that the software ecosystem is nice, well documented and the chip is very capable.
You are right, the ESP32's in general are great other than the ADC. Super low cost and unlike other MCU suppliers (Microchip, TI and STM), I could get ESP32-C3's during COVID - and that is the reason I used them in two projects, albeit at risk. Also used an ESP32-S3-WROOM. You can calibrate the ADC's but still they are mediocre at best. No good for accurate analogue measurements, but I did use it on one project for a non-critical battery fuel gauge (could not get fuel gauge chips during COVID) and it was OK.
Espressif's BLE documentation is a dog's breakfast. Their hardware datasheets has ambiguity in them and is missing some detail that would be found in, say, TI and Analog Devices datasheets. The ecosystem is satisfactory but not great. Mind you I recently found a glaring pin-out error in Texas Instruments two year-old chip that no-one at TI had even picked up. The pinout list showed input pin for CAN bus data incorrectly described as a chip enable pin :wtf: TI's documentation QA is in trouble if such an error can exist for two years before they know about it. Overall Espressif does a reasonable job with their English documentation, considering it is a Chinese company.
No complaints though, because ESP32's got me out of a bind during COVID. Super low cost, which is good for high volume cost-sensitive projects. Plus I learnt to use a new MCU.
Which TI chip? I get it fixed.
The ISOW1044BDFMR. I did report it about 3 weeks ago, and to TI's credit they fixed it immediately and re-released the document. Pin 3 was listed as a chip enable when it was in fact a transmit data line.
I find it incredible no-one else has ever used this chip, of if they have, they are too busy or self-centred to report the error. Mind you, if I reported every bug in Altium, I'd never get any work done.
I was pleasantly surprised at TI’s responsiveness to datasheet errors. I once found an error in the website description of some weird version of the 5534 op-amp (perhaps a mil-spec version or somethinf), where it was described as a quad op-amp (it’s a single). They fixed it right away.
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The UTI (universal transducer interface) from Smartec.
https://smartec-sensors.eu/cms/pages/products/uti-interface.php
It can measure capacitance down to a 2pF range (14-bit resolution) over long cables, more or less regardless of cable capacitance. I used it (in the 0-300pF range) to measure the level of liquid xenon in a cryostat through 3m of coax cable (at 100pF/m). Measurements reproducible down to 0.02pF with averaging.
It can also do resistance, e.g. for PT1000’s.
Downside is that it’s hard to find. None of the major distributors carry it any more, so you have to find a small local distributor.
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The UTI (universal transducer interface) from Smartec.
https://smartec-sensors.eu/cms/pages/products/uti-interface.php (https://smartec-sensors.eu/cms/pages/products/uti-interface.php)
Nice. Quite a useful part, unfortunate name...
Along the same lines, TI has the TDC7200 for ultrasonic timing measurements.
https://www.ti.com/product/TDC7200 (https://www.ti.com/product/TDC7200)
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The UTI (universal transducer interface) from Smartec.
https://smartec-sensors.eu/cms/pages/products/uti-interface.php (https://smartec-sensors.eu/cms/pages/products/uti-interface.php)
Nice. Quite a useful part, unfortunate name...
Ain't that the truth! ;D
Along the same lines, TI has the TDC7200 for ultrasonic timing measurements.
https://www.ti.com/product/TDC7200 (https://www.ti.com/product/TDC7200)
Neat!
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Chip of the day = TMP1075
https://www.ti.com/lit/ds/symlink/tmp1075.pdf (https://www.ti.com/lit/ds/symlink/tmp1075.pdf)
https://www.digikey.com/en/products/detail/texas-instruments/TMP1075NDRLR/15222310 (https://www.digikey.com/en/products/detail/texas-instruments/TMP1075NDRLR/15222310)
$0.64 in 1s, $0.25 in 4000s.
-40°C ~ 125°C Range, I2C Interface, Tiny SOT-563 package, Thermal Alert Output. Measure thermal load or ambient temp with a cutout.
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TMP1075
$0.64 in 1s, $0.25 in 4000s.
-40°C ~ 125°C Range, I2C Interface, Tiny SOT-563 package, Thermal Alert Output. Measure thermal load or ambient temp with a cutout.
... NIST traceable tested!
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I like OPA991 family (or the 992 upgrade). Quite a universal opamp.
TI are iterating on "universal opamp" with others like OPAx828, or chopper OPAx189 lots of progress with analog capabilities still growing.
Wow. Those are some impressive specs..
THD + noise 0.00006% :scared:
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Meanwhile they provide PowerPAD packages for opamps to reduce self-heating. Amazing how improvements in analog technology still continue.
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I'm not sure if this is officially a chip of the day considering I haven't personally use it yet... but
(https://mm.digikey.com/Volume0/opasdata/d220001/medias/images/4274/MFG_PowerPAK-8X8LR_View2.jpg)
SQJQ184ER-T1_GE3
https://www.digikey.com/en/products/detail/vishay-siliconix/SQJQ184ER-T1-GE3/16181886 (https://www.digikey.com/en/products/detail/vishay-siliconix/SQJQ184ER-T1-GE3/16181886)
https://www.vishay.com/docs/71298/sqjq184er.pdf (https://www.vishay.com/docs/71298/sqjq184er.pdf)
QTY UNIT PRICE EXT PRICE
1 $3.53000 $3.53
10 $2.96500 $29.65
100 $2.39890 $239.89
500 $2.13232 $1,066.16
1,000 $1.82579 $1,825.79
N-Channel MOSFET, 80V, 1.4mOhm Rds-on, 430A Id25, 600W 8-PowerSMD
That is a serious little FET!
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This one could be super useful.....
TPL5110QDDCRQ1
It's a timer/power gating high side switch chip. So for example if you want to only power up your system every x seconds, do something, then power down to save batteries. Timer intervals from 100ms to 7200s and 35nA quiescent current draw for this chip. Could be super useful if your system doesn't have a deep sleep mode or otherwise lots of quiescent current.
https://www.digikey.com/en/products/detail/texas-instruments/TPL5110QDDCRQ1/6816812 (https://www.digikey.com/en/products/detail/texas-instruments/TPL5110QDDCRQ1/6816812)
https://www.ti.com/lit/ds/symlink/tpl5110-q1.pdf (https://www.ti.com/lit/ds/symlink/tpl5110-q1.pdf)
QTY UNIT PRICE EXT PRICE
1 $0.88000 $0.88
100 $0.61560 $61.56
1,000 $0.40148 $401.48
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App note of the day...
https://www.ti.com/lit/an/snvaa85/snvaa85.pdf (https://www.ti.com/lit/an/snvaa85/snvaa85.pdf)
"How to Implement a Simple Constant Current Regulation Scheme to a PCM Based Buck"
Sort of a cool hack to add CC to a buck regulator with PCM.