TURUL LLC

FLT-001-A-61, SN 260721005

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.

Factory test certificate

Serial 260721005

Result
PASS
PCB revision
Rev A
Test date
2026-07-30
Option A (op-amp)
MCP6002 class
Option B (supply protection)
Supply OVP + reverse-polarity protection

Frequency response check

Passband gain at the golden reference cutoff (−3 dB point) for each DIP setting.

Cutoff Golden fc1 Measured @ golden fc2 DIP switches3
1 Hz 0.997 Hz -2.93 dB SW1 pos 1 ON, pos 2–4 OFF (1000)
10 Hz 10.15 Hz -2.91 dB SW1 pos 1–2 ON, pos 3–4 OFF (1100)
100 Hz 102.48 Hz -2.87 dB SW1 pos 1–3 ON, pos 4 OFF (1110)
1 kHz 1.04 kHz -2.88 dB SW1 pos 1–4 ON (1111)
10 kHz 10.19 kHz -2.88 dB SW1 pos 1–4 OFF (0000)
23.4 kHz 23.09 kHz -2.82 dB 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. Gain of your unit measured at the golden reference cutoff frequency for that DIP setting.
  3. 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.

DC linearity check

Factory DC sweep: 60 setpoints (100 mV steps 0…4.9 V, then 10 mV steps 4.91…5.0 V). This certificate lists selected summary steps — for the full curve, see the DC linearity charts below.

Unloaded 0 Hz transfer at the setpoints below.

Set (V) Vin (V) Vout (V) Δ (mV)1
0.00 -0.001 0.000 +0.5 mV
0.10 0.097 0.098 +0.5 mV
1.00 0.999 0.999 +0.6 mV
2.00 2.000 2.001 +0.5 mV
3.00 3.002 3.002 0.0 mV
4.00 4.003 4.003 0.0 mV
4.90 4.905 4.904 −0.5 mV
4.95 4.957 4.956 −1.1 mV
4.96 4.966 4.965 −1.1 mV
4.97 4.976 4.976 −0.6 mV
4.98 4.986 4.985 −1.1 mV

Max |Δ| across the factory sweep: 1.6 mV (full curve on the charts below).

  1. Unloaded DC transfer at 0 Hz. Δ = Vout − Vin; 0 mV = ideal unity gain. Not the same as loaded use through the 1 kΩ output resistor.

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 + unit 260721005

Golden mean from three reference boards; green star marks your unit at each cutoff. Use the legend to show individual golden boards.

DC linearity — golden reference + unit 260721005

Unloaded Vin→Vout at 0 Hz — full factory sweep (100 mV steps, plus fine steps above 4.9 V). Green line: your factory DC sweep. 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 Unit 260721005 Δ
0.00 +0.2 mV +0.5 mV
0.10 0.0 mV +0.5 mV
1.00 −0.4 mV +0.6 mV
2.00 −0.3 mV +0.5 mV
3.00 −0.6 mV 0.0 mV
4.00 +0.5 mV 0.0 mV
4.90 −0.6 mV −0.5 mV
4.95 0.0 mV −1.1 mV
4.96 −0.4 mV −1.1 mV
4.97 −0.6 mV −0.6 mV
4.98 −0.6 mV −1.1 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