From Newsgroup: sci.electronics.design


Maybe people should post something electronic to SED once in a while.

This isn't very exciting, I admit.

https://www.dropbox.com/scl/fi/8rvu5s91nwha7zlblxgcb/B200_DAC_1.jpg?rlkey=8071q2dkcgjsbwewsyczrg4gg&raw=1

https://www.dropbox.com/scl/fi/d8gqf6o2p16ixyu83cmk4/B200_Output_2.asc?rlkey=fdwnl07gv9aml6mjny1aao1id&dl=0


The challenge here is the dreadful DAC7822 data sheet. Data sheets
keep getting worse.






John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

Maybe people should post something electronic to SED once in a while.

This isn't very exciting, I admit.

https://www.dropbox.com/scl/fi/8rvu5s91nwha7zlblxgcb/B200_DAC_1.jpg?rlkey=8071q2dkcgjsbwewsyczrg4gg&raw=1

https://www.dropbox.com/scl/fi/d8gqf6o2p16ixyu83cmk4/B200_Output_2.asc?rlkey=fdwnl07gv9aml6mjny1aao1id&dl=0

The challenge here is the dreadful DAC7822 data sheet. Data sheets
keep getting worse.

Just downloaded that datasheet,
it has 'OBSOLETE' in big characters displayed on every one of the 12 pages. Indeed a bit mysterious design, no application notes?

There must be other better? 16 bit DAC chips.
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On Mon, 29 Sep 2025 16:02:35 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

Maybe people should post something electronic to SED once in a while.

This isn't very exciting, I admit.

https://www.dropbox.com/scl/fi/8rvu5s91nwha7zlblxgcb/B200_DAC_1.jpg?rlkey=8071q2dkcgjsbwewsyczrg4gg&raw=1
https://www.dropbox.com/scl/fi/d8gqf6o2p16ixyu83cmk4/B200_Output_2.asc?rlkey=fdwnl07gv9aml6mjny1aao1id&dl=0

The challenge here is the dreadful DAC7822 data sheet. Data sheets
keep getting worse.

Just downloaded that datasheet,
it has 'OBSOLETE' in big characters displayed on every one of the 12 pages. >Indeed a bit mysterious design, no application notes?

There must be other better? 16 bit DAC chips.

That's strange. I just reloaded the data sheet from TI and don't see
that.

This

https://www.ti.com/product/DAC7822#order-quality

says status is production+active.

I want to close a control loop inside an FPGA. This DAC is fast, and
the ADC3910S025 is fast. I could run both at 20 MHz.






John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

"john larkin" <jl@glen--canyon.com> wrote in message news:rs7ldk9q7lu4h8tle74qj3toddkqkrgvoa@4ax.com...

Maybe people should post something electronic to SED once in a while.

This isn't very exciting either but not long ago someone asked me if a 12V 1A linear regulator was possible with the
pass transistor's case mounted directly on grounded metal.
So I suggested this with a TIP122. This has been changed so that no other files are needed.

Watch out for line wraps and u symbol issues for C5,7,9,10

Version 4.1
SHEET 1 4960 1688
WIRE -304 -160 -400 -160
WIRE -160 -160 -240 -160
WIRE -160 -144 -160 -160
WIRE -112 -144 -160 -144
WIRE 544 -144 -112 -144
WIRE 736 -144 544 -144
WIRE 832 -144 736 -144
WIRE 896 -144 832 -144
WIRE 992 -144 896 -144
WIRE 1056 -144 992 -144
WIRE 1120 -144 1056 -144
WIRE -400 -112 -400 -160
WIRE -304 -112 -400 -112
WIRE -160 -112 -160 -144
WIRE -160 -112 -240 -112
WIRE 544 -80 544 -144
WIRE 736 -80 736 -144
WIRE -704 -64 -832 -64
WIRE -512 -64 -624 -64
WIRE -448 -64 -512 -64
WIRE -400 -64 -400 -112
WIRE -400 -64 -448 -64
WIRE 832 -64 832 -144
WIRE -304 -48 -352 -48
WIRE -160 -48 -160 -112
WIRE -160 -48 -240 -48
WIRE -832 -16 -832 -64
WIRE -704 -16 -704 -64
WIRE -624 -16 -624 -64
WIRE -448 -16 -448 -64
WIRE -352 0 -352 -48
WIRE -304 0 -352 0
WIRE -160 0 -160 -48
WIRE -160 0 -240 0
WIRE 544 32 544 0
WIRE 624 32 544 32
WIRE -112 48 -112 -144
WIRE -352 64 -352 0
WIRE -304 64 -352 64
WIRE -160 64 -240 64
WIRE 736 80 736 0
WIRE 736 80 688 80
WIRE 832 96 832 16
WIRE -832 112 -832 64
WIRE -704 112 -704 64
WIRE -704 112 -832 112
WIRE -624 112 -624 64
WIRE -512 112 -624 112
WIRE -448 112 -448 48
WIRE -448 112 -512 112
WIRE -352 112 -352 64
WIRE -352 112 -448 112
WIRE -304 112 -352 112
WIRE -160 112 -160 64
WIRE -160 112 -240 112
WIRE -400 192 -400 -64
WIRE -304 192 -400 192
WIRE -160 192 -160 112
WIRE -160 192 -240 192
WIRE 896 208 896 -144
WIRE 992 208 992 -144
WIRE 736 224 736 80
WIRE 832 224 832 176
WIRE 832 224 736 224
WIRE 1120 224 1120 -144
WIRE -400 240 -400 192
WIRE -304 240 -400 240
WIRE -160 240 -160 192
WIRE -160 240 -240 240
WIRE -112 240 -112 112
WIRE -112 240 -160 240
WIRE -80 240 -112 240
WIRE -32 240 -80 240
WIRE 16 240 -32 240
WIRE 96 240 16 240
WIRE 240 240 192 240
WIRE 400 240 240 240
WIRE 432 240 400 240
WIRE 624 240 624 128
WIRE 624 240 432 240
WIRE 656 240 624 240
WIRE 736 240 736 224
WIRE 736 240 720 240
WIRE 16 272 16 240
WIRE 400 272 400 240
WIRE 240 288 240 240
WIRE 544 320 544 32
WIRE 544 320 480 320
WIRE -80 336 -80 240
WIRE 16 368 16 336
WIRE 80 368 16 368
WIRE 144 368 144 304
WIRE 144 368 80 368
WIRE 352 384 352 336
WIRE 480 384 480 320
WIRE 16 400 16 368
WIRE 736 400 736 240
WIRE 544 416 544 320
WIRE 304 448 272 448
WIRE 432 448 400 448
WIRE 448 448 448 336
WIRE 448 448 432 448
WIRE -80 528 -80 416
WIRE -32 528 -80 528
WIRE 16 528 16 480
WIRE 16 528 -32 528
WIRE 240 528 240 368
WIRE 240 528 16 528
WIRE 272 528 272 448
WIRE 272 528 240 528
WIRE 320 528 272 528
WIRE 432 528 432 448
WIRE 432 528 400 528
WIRE 480 528 480 448
WIRE 480 528 432 528
WIRE 544 528 544 480
WIRE 544 528 480 528
WIRE 736 528 736 480
WIRE 736 528 544 528
WIRE 896 528 896 272
WIRE 896 528 736 528
WIRE 992 528 992 272
WIRE 992 528 896 528
WIRE 1120 528 1120 304
WIRE 1120 528 992 528
WIRE 1120 560 1120 528
FLAG 1120 560 0
FLAG 1056 -144 12V1A
FLAG -32 240 Rec
FLAG -32 528 Sens
FLAG -512 -64 vta
FLAG -512 112 vtb
FLAG 432 240 drive
FLAG 80 368 lim
SYMBOL ind -608 80 R180
WINDOW 0 -35 92 Left 2
WINDOW 3 -75 63 Left 2
SYMATTR InstName L2
SYMATTR Value 0.04H
SYMATTR Type ind
SYMBOL ind -720 -32 R0
WINDOW 0 -35 20 Left 2
WINDOW 3 -39 46 Left 2
SYMATTR InstName L1
SYMATTR Value 2H
SYMATTR Type ind
SYMATTR SpiceLine Rser=5
SYMBOL diode -304 -96 R270
WINDOW 0 15 -1 VTop 2
WINDOW 3 2 54 VBottom 2
SYMATTR InstName D1
SYMATTR Value RSX301LAM30
SYMBOL voltage -832 -32 R0
WINDOW 3 -263 37 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
WINDOW 0 14 4 Left 2
SYMATTR Value SINE(0 163 60)
SYMATTR InstName V1
SYMBOL polcap -128 48 R0
SYMATTR InstName C5
SYMATTR Value 1000|
SYMATTR SpiceLine V=25 Irms=1.69 Rser=0.034 Lser=0 mfg="Panasonic" pn="ECA1EFQ102" type="Al electrolytic"
SYMBOL res -64 320 M0
SYMATTR InstName R1
SYMATTR Value 0.51
SYMATTR SpiceLine pwr=1
SYMBOL res 0 384 R0
SYMATTR InstName R2
SYMATTR Value 22k
SYMBOL npn 192 304 M270
WINDOW 0 62 57 VLeft 2
WINDOW 3 -6 147 VLeft 2
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL res 256 272 M0
SYMATTR InstName R3
SYMATTR Value 3.3k
SYMBOL res 416 512 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 22
SYMATTR SpiceLine pwr=2
SYMBOL pnp 688 128 R180
WINDOW 0 42 59 Left 2
WINDOW 3 41 33 Left 2
SYMATTR InstName Q3
SYMATTR Value 2N3906
SYMBOL res 528 -96 R0
SYMATTR InstName R5
SYMATTR Value 2.2k
SYMBOL res 752 -96 M0
SYMATTR InstName R6
SYMATTR Value 1.8k
SYMBOL res 1104 208 R0
SYMATTR InstName R8
SYMATTR Value 12
SYMBOL zener 560 480 R180
WINDOW 0 -40 29 Left 2
WINDOW 3 -159 1 Left 2
SYMATTR InstName D6
SYMATTR Value BZX84C6V2L
SYMBOL cap 880 208 R0
SYMATTR InstName C9
SYMATTR Value 100|
SYMATTR SpiceLine V=16 Irms=4.8 Rser=0.0064 Lser=3.543n mfg="Wnrth Elektronik" pn="870135373001 WCAP-PTHT 6,3 x 11" type="Al
polymer"
SYMBOL cap 496 384 M0
WINDOW 0 -22 -17 Left 2
WINDOW 3 -43 7 Left 2
SYMATTR InstName C8
SYMATTR Value 100n
SYMATTR SpiceLine V=10 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM022R61A104KE01" type="X5R"
SYMBOL res 720 496 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R7
SYMATTR Value 1.5k
SYMBOL cap -240 -176 R90
WINDOW 0 15 63 VBottom 2
WINDOW 3 -14 -5 VTop 2
SYMATTR InstName C1
SYMATTR Value 10n
SYMBOL cap -240 -64 R90
WINDOW 0 14 63 VBottom 2
WINDOW 3 -16 -4 VTop 2
SYMATTR InstName C2
SYMATTR Value 10n
SYMBOL cap -240 48 R90
WINDOW 0 12 62 VBottom 2
WINDOW 3 -15 -4 VTop 2
SYMATTR InstName C3
SYMATTR Value 10n
SYMBOL cap -240 176 R90
WINDOW 0 12 67 VBottom 2
WINDOW 3 -16 -2 VTop 2
SYMATTR InstName C4
SYMATTR Value 10n
SYMBOL polcap 32 336 R180
WINDOW 0 24 57 Left 2
WINDOW 3 24 8 Left 2
SYMATTR InstName C7
SYMATTR Value 10|
SYMATTR SpiceLine V=2.5 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM155R60E106ME16" type="X5R"
SYMBOL TVSdiode -464 -16 R0
WINDOW 0 -36 18 Left 2
WINDOW 3 -119 73 Left 2
SYMATTR InstName D5
SYMATTR Value SMBJ24CA
SYMBOL cap 976 208 R0
SYMATTR InstName C10
SYMATTR Value 0.22|
SYMATTR SpiceLine V=16 Irms=0 Rser=0.0118 Lser=347p mfg="Wnrth Elektronik" pn="885012105017 WCAP-CSGP 0402" type="X5R"
SYMBOL res 848 -80 M0
SYMATTR InstName R9
SYMATTR Value 33k
SYMBOL res 848 80 M0
SYMATTR InstName R10
SYMATTR Value 10k
SYMBOL cap 720 224 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C12
SYMATTR Value 1n
SYMBOL diode -304 16 R270
WINDOW 0 20 -1 VTop 2
WINDOW 3 2 54 VBottom 2
SYMATTR InstName D2
SYMATTR Value RSX301LAM30
SYMBOL diode -240 128 M270
WINDOW 0 20 68 VTop 2
WINDOW 3 2 11 VBottom 2
SYMATTR InstName D3
SYMATTR Value RSX301LAM30
SYMBOL diode -240 256 M270
WINDOW 0 22 67 VTop 2
WINDOW 3 -2 10 VBottom 2
SYMATTR InstName D4
SYMATTR Value RSX301LAM30
SYMBOL npn 400 384 R90
WINDOW 0 -6 61 VRight 2
WINDOW 3 -4 -45 VRight 2
SYMATTR InstName Q4
SYMATTR Value 2N3055
SYMBOL npn 448 272 R90
WINDOW 0 -9 91 VLeft 2
WINDOW 3 -8 39 VLeft 2
SYMATTR InstName Q2
SYMATTR Value 2N3904
TEXT -1104 80 Left 2 !.tran 0 10 1 startup
TEXT -736 -104 Left 2 !K1 L1 L2 0.97

This isn't very exciting, I admit.

https://www.dropbox.com/scl/fi/8rvu5s91nwha7zlblxgcb/B200_DAC_1.jpg?rlkey=8071q2dkcgjsbwewsyczrg4gg&raw=1

https://www.dropbox.com/scl/fi/d8gqf6o2p16ixyu83cmk4/B200_Output_2.asc?rlkey=fdwnl07gv9aml6mjny1aao1id&dl=0

The challenge here is the dreadful DAC7822 data sheet. Data sheets
keep getting worse.

John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On Mon, 29 Sep 2025 16:02:35 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

Maybe people should post something electronic to SED once in a while.

This isn't very exciting, I admit.

https://www.dropbox.com/scl/fi/8rvu5s91nwha7zlblxgcb/B200_DAC_1.jpg?rlkey=8071q2dkcgjsbwewsyczrg4gg&raw=1
https://www.dropbox.com/scl/fi/d8gqf6o2p16ixyu83cmk4/B200_Output_2.asc?rlkey=fdwnl07gv9aml6mjny1aao1id&dl=0

The challenge here is the dreadful DAC7822 data sheet. Data sheets
keep getting worse.

Just downloaded that datasheet,
it has 'OBSOLETE' in big characters displayed on every one of the 12 pages. >>Indeed a bit mysterious design, no application notes?

There must be other better? 16 bit DAC chips.

That's strange. I just reloaded the data sheet from TI and don't see
that.

My error,
I typed DAC7822 in Chromium browser and it found this: https://www.alldatasheet.com/datasheet-pdf/pdf/657266/AD/AD7882.html

This

https://www.ti.com/product/DAC7822#order-quality

says status is production+active.

OK, got that datasheet now, seems a normal R2R DA network, see figure 37.

I want to close a control loop inside an FPGA. This DAC is fast, and
the ADC3910S025 is fast. I could run both at 20 MHz.

I used a simpler 8 bit R2R network with normal resistors connected to my old FPPGA board for analog video output:
https://panteltje.nl/pub/FPGA_board_with_25MHz_VCXO_locked_to_rubidium_10MHz_reference_IMG_3724.GIF
Have not tried what the maximum speed is, but plenty for normal analog video. --- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On Mon, 29 Sep 2025 18:07:17 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

On Mon, 29 Sep 2025 16:02:35 GMT, Jan Panteltje <alien@comet.invalid> >>wrote:

Maybe people should post something electronic to SED once in a while.

This isn't very exciting, I admit.

https://www.dropbox.com/scl/fi/8rvu5s91nwha7zlblxgcb/B200_DAC_1.jpg?rlkey=8071q2dkcgjsbwewsyczrg4gg&raw=1
https://www.dropbox.com/scl/fi/d8gqf6o2p16ixyu83cmk4/B200_Output_2.asc?rlkey=fdwnl07gv9aml6mjny1aao1id&dl=0

The challenge here is the dreadful DAC7822 data sheet. Data sheets
keep getting worse.

Just downloaded that datasheet,
it has 'OBSOLETE' in big characters displayed on every one of the 12 pages. >>>Indeed a bit mysterious design, no application notes?

There must be other better? 16 bit DAC chips.

That's strange. I just reloaded the data sheet from TI and don't see
that.

My error,
I typed DAC7822 in Chromium browser and it found this: >https://www.alldatasheet.com/datasheet-pdf/pdf/657266/AD/AD7882.html

This

https://www.ti.com/product/DAC7822#order-quality

says status is production+active.

OK, got that datasheet now, seems a normal R2R DA network, see figure 37.

The note above fig 41 is especially insightful. TI must use their
dumbest interns to write data sheets.

I want to close a control loop inside an FPGA. This DAC is fast, and
the ADC3910S025 is fast. I could run both at 20 MHz.

I used a simpler 8 bit R2R network with normal resistors connected to my old FPPGA board for analog video output:
https://panteltje.nl/pub/FPGA_board_with_25MHz_VCXO_locked_to_rubidium_10MHz_reference_IMG_3724.GIF
Have not tried what the maximum speed is, but plenty for normal analog video.

Analog video?

I have a prototype board now being built that has a small (efinix T20)
FPGA driving six discrete resistors to make a fast DAC, for a direct-digital-synthsizer experiment.

I could buy a little R-2R network for production, if the idea works.

John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On Mon, 29 Sep 2025 18:07:17 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

On Mon, 29 Sep 2025 16:02:35 GMT, Jan Panteltje <alien@comet.invalid> >>>wrote:

Maybe people should post something electronic to SED once in a while. >>>>>
This isn't very exciting, I admit.

https://www.dropbox.com/scl/fi/8rvu5s91nwha7zlblxgcb/B200_DAC_1.jpg?rlkey=8071q2dkcgjsbwewsyczrg4gg&raw=1
https://www.dropbox.com/scl/fi/d8gqf6o2p16ixyu83cmk4/B200_Output_2.asc?rlkey=fdwnl07gv9aml6mjny1aao1id&dl=0

The challenge here is the dreadful DAC7822 data sheet. Data sheets >>>>>keep getting worse.

Just downloaded that datasheet,
it has 'OBSOLETE' in big characters displayed on every one of the 12 pages. >>>>Indeed a bit mysterious design, no application notes?

There must be other better? 16 bit DAC chips.

That's strange. I just reloaded the data sheet from TI and don't see >>>that.

My error,
I typed DAC7822 in Chromium browser and it found this: >>https://www.alldatasheet.com/datasheet-pdf/pdf/657266/AD/AD7882.html

This

https://www.ti.com/product/DAC7822#order-quality

says status is production+active.

OK, got that datasheet now, seems a normal R2R DA network, see figure 37.

The note above fig 41 is especially insightful. TI must use their
dumbest interns to write data sheets.

I want to close a control loop inside an FPGA. This DAC is fast, and
the ADC3910S025 is fast. I could run both at 20 MHz.

I used a simpler 8 bit R2R network with normal resistors connected to my old FPPGA board for analog video output:
https://panteltje.nl/pub/FPGA_board_with_25MHz_VCXO_locked_to_rubidium_10MHz_reference_IMG_3724.GIF
Have not tried what the maximum speed is, but plenty for normal analog video.

Analog video?

Yes, NTSC and PAL(for Europe),
was before all TV went digital here.
That said I have 4 analog output Sony starlight security cameras running 24/7, being recorded on a Raspberry Pi via a Chinese interface box.
Plus some for experiments
https://panteltje.nl/pub/target_tracking_test_IMG_4688.JPG

I have a prototype board now being built that has a small (efinix T20)
FPGA driving six discrete resistors to make a fast DAC, for a >direct-digital-synthsizer experiment.

The 'limiting' thing is how steady the high voltage on the FPGA pins is due to the loads the resistors form.
So low value resistors give more current load but also more speed.
Else some digital buffer may be needed?

I could buy a little R-2R network for production, if the idea works.

Yes, resistor tolerances would then likely be low.
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On 9/29/2025 11:07 AM, john larkin wrote:

Maybe people should post something electronic to SED once in a while.

ASCII schematics used to make it fun, especially when every post in a
thread had one.
That was even better than alt.binaries.schematics.electronic

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On Thu, 2 Oct 2025 21:40:08 -0400, Tom Del Rosso <fizzbintuesday@that-google-mail-domain.com> wrote:

On 9/29/2025 11:07 AM, john larkin wrote:

Maybe people should post something electronic to SED once in a while.

ASCII schematics used to make it fun, especially when every post in a
thread had one.
That was even better than alt.binaries.schematics.electronic

I hate ascii schematics.

Just sketch or whiteboard and take a pic.

LT Spice .asc posts are OK, a bit of a nuisance to view, if they
actually work. Most are really hideous.



John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
--- Synchronet 3.21a-Linux NewsLink 1.2