TURUL LLC

FLT-001

Mini Filter

Compact active low-pass filter for sensor signals before your MCU ADC. Breadboard-friendly 2.54 mm headers, six DIP-selectable cutoffs.

Tindie Etsy
Mini Filter PCB, top view
Top view
Board back — HOST and SENSOR pads
Back — HOST / SENSOR
Mini Filter in ESD bag with reference label
In bag + label

Click a photo to enlarge. Package contents: User's Guide §2.

Ordering options

Option A — Op-amp (precision / stability)

  • 0 — No op-amp populated
  • 1 — Microchip MCP6022
  • 2 — Microchip MCP6V27
  • 3 — Microchip MCP6002
  • 4 — TI OPA2333
  • 5 — TI OPA2350
  • 6 — MCP6002 class

Option B — Supply protection1

  • 0 — No supply protection
  • 1 — OVP + reverse-polarity on power input
  1. Protects the op-amp from supply abuse (wrong voltage, reversed power). This is not signal or input protection. When populated (Option B = 1), the over-voltage trip level is set with ±0.1% resistors — tighter than the 1% parts in the filter path — so the clamp stays at the designed threshold. More details in the User's Guide.

Golden reference — Rev A

Characterization updated 2026-08-10 10:30:16

Cutoff Golden fc1 DIP switches2
1 Hz 0.997 Hz SW1 pos 1 ON, pos 2–4 OFF (1000)
10 Hz 10.15 Hz SW1 pos 1–2 ON, pos 3–4 OFF (1100)
100 Hz 102.48 Hz SW1 pos 1–3 ON, pos 4 OFF (1110)
1 kHz 1.04 kHz SW1 pos 1–4 ON (1111)
10 kHz 10.19 kHz SW1 pos 1–4 OFF (0000)
23.4 kHz 23.09 kHz SW1 pos 1 OFF, pos 2–4 ON (0111)
  1. Golden fc — corner frequency at −3 dB relative to passband gain, measured on three reference boards (Rev A).
  2. DIP switch setting on SW1 — pos 1 through pos 4 are the four levers on that package; the four-digit pattern (e.g. 0111) lists pos 1→pos 4 left to right (1 = ON). More details in the User's Guide.

Frequency response — golden reference

Mean of three golden boards; open a PASS serial (?sn=) to overlay your unit. Use the legend to show individual golden boards.

DC linearity — golden reference

Unloaded Vin→Vout at 0 Hz — full factory sweep (100 mV steps, plus fine steps above 4.9 V). Open a PASS serial (?sn=) to overlay your unit. Not the same as loaded use through the 1 kΩ output resistor.

Transfer curve — Vin vs Vout

DC error — (Vout − Vin) vs Vin

Deviation from ideal unity gain in millivolts (Δ = Vout − Vin). Vertical scale ±8 mV (2 mV ticks). Shaded green band ±5 mV = factory PASS limit; red zones = outside PASS. White dashed line = 0 mV (ideal unity). Full 0…5 V horizontal range.

Setpoint summary — selected steps (Δ in mV)

Golden mean vs your unit at selected summary setpoints (when ?sn=).

Set (V) Golden mean Δ
0.00 +0.2 mV
0.10 0.0 mV
1.00 −0.4 mV
2.00 −0.3 mV
3.00 −0.6 mV
4.00 +0.5 mV
4.90 −0.6 mV
4.95 0.0 mV
4.96 −0.4 mV
4.97 −0.6 mV
4.98 −0.6 mV

User's Guide

Pinout, breadboard fit, DIP switch settings, ordering options, and factory certificate — on a separate page so this product view stays fast.

Open User's Guide