Categories
kicad-symbol

OPA858, OPA855, OPA859

High-speed op-amps from TI, in a somewhat challenging WSON8-package...

OPA858 is a 5.5 GHz GBWP FET-input amplifier (stable at gains >= 7V/V), and the OPA859 looks like a slower 1.8 GHz unity-gain stable version.

OPA855 is a 8 GHz bipolar input opamp, gain >=7V/V.

These should be useful where OPA847 and OPA659 were used previously, e.g. in high-speed transimpedance amplifiers.

Categories
kicad-footprint

SO-20 Texas PowerPAD

SO-20 PowerPAD footprint as used by e.g. OPA569

Categories
kicad-symbol

LTC1562

LTC1562 quad op-amp for building active filters at 10 kHz to 150 kHz.

Categories
Electronics

Pulse distribution amplifier rise-time measurement

With a longish BNC-cable between a PDA-output and a 4 GHz oscilloscope we see a 10%-to-90% rise-time of <700 ps.

Categories
Time and Frequency

clock-transition scan at 128x speedup

Recorded at 2x speed with OBS from the youtube live-stream, then converted to MP4 with VLC, then run twice through Garmin Virb Edit producing 8x speedup both times.

Categories
Time and Frequency

88Sr+ clock transition in a low magnetic field

Live-stream from the VTT MIKES ion-clock lab

We've completed a second magnetic shielding layer, based on the same plywood+METGLAS concept as the first shield. This should further shield the 88Sr+ ion from unwanted magnetic field fluctuations. To further reduce the DC-field we've now applied a counter-field using a few milliAmps of current through three coils that surround the ion trap.

When the Zeeman components are this close together (the field is <0.4 uT) it is fairly quick to scan over the components. Here we see the four innermost pairs of peaks +/-C1 through +/-C4 of the clock-transition at 445 THz (674nm red light!). One scan runs in about one hour - and will be plotted on top of the older scans. We shoot 100 pulses of the laser-light at the ion and the height of the bar shows how many times we successfully drove the ion into the dark clock-state.

Categories
Electronics

Multiplexer S/N 4

Slight design changes to the RF Multiplexer design.

Front panel buttons B1 and B2 now extend out of the front-panel and are easily accessible. Pressing the buttons advances the state of the MUX1 and MUX2 boards.

Transmission bandwidth. This MUX has 50-Ohm impedance relays, and the 3dB bandwidth is around 1.0-1.2 GHz.
Inside of MUX-box. Two 1:8 boards with BNC connectors side-by-side. Arduino MKRZERO and Ethernet Shield on the right. A simple carrier board distributes SPI-signals from the Arduino to the MUX-boards and provides front-panel pushbuttons and LEDs. Top center is a 230VAC to 5VDC powersupply. Top left 230VAC input.

Categories
woodworking

Plywood box glueup

Kiilto B3 glue with 15mm x 15mm triangle-profile in the corners. Using a helper-profile with a plastic release-film worked quite well for clamping.

Categories
woodworking

More laser cutting

2mm plywood cut with 50W CO2 laser

Laser cut plywood test-project: a 2V geodesic sphere, diameter 200mm. Next is sanding the triangles a bit and then figuring out how to connect them neatly together.

Categories
woodworking

Torsion-box workbench with parfguide hole-pattern

(Built a few months ago, but better blog late than never..)

Here's a 1600mm-by-930 mm workbench built from two sheets (1220mm x 2440mm, 4-by-8 metric feet) of 15mm plywood. It's a torsion-box design with the top and bottom sheets separated by 240mm. The sides have rounded openings that create storage-bays for tools etc. The top has 20mm diameter holes drilled using the parfguide-system (it uses pythagoras 3-4-5 triangles to get the holes reasonably accurately positioned). The hole-grid is 10x17 so there are 170 holes in total. Assembled using pocket-hole screws.

Here's a rough sketch of the dimensions. The dimensions were chosen to fit my workshop, so that it could be built from two 1220mm-by-2440mm sheets, and the dimensions rounded to fit the 96mm-by-96mm parfguide hole pattern nicely.

Sketch of dimensions.

The pieces needed can be cut from two sheets of plywood, resulting in two top/bottom pieces, two long-sides, two short-sides, and four internal dividers. I only used two of the dividers.

sketch of how to cut the pieces from a sheet of plywood.

There are a lot of torsion-box or "Paulk workbench" builds out there, here are some links: