SCF-2

Features

• Digital Inputs or Outputs
• (2) 3.5mm Jacks
• Scaling resistors
• Schottky Clamping Diodes
• Filter cap
• Ring pin brought to connector
  • Ring pin is not used in Synth applications
  • Card can be used as a 3.5mm breakout (1x5 vertical header mounted to rear)
• (2) 4-40 mounting holes
• 36mmx28mm

Schematic

Used as Digital Input

• 550K input impedance presents light load
• R1/R3 - Input scale resistors
  • Ex: 5.0V control voltage to 3.0 V
• Clipping diodes protect inputs
• R1/C1 create input filter = 2.2mS = 454 Hz

Used as Digital Output

• Drive with 5V low output impedance source
• DNP R3, C1
• Use lower value for R1 (typically 200 Ohms, etc)
• Can leave Clipping Diodes to protect driver

Connectors

J1, J2 - 3.5mm Jacks

• Tip
• Sleeve

J3 - I/O Connector

• 2x4 Header, 0.1"
• Either 2x4 (Stereo) or 1x4 (mono)
  • Install 1x4 on 1,3,5,7 pointing down for breadboard

• Pinout

1. VCC
2. VCC
3. VP1 - Tip J1
4. VR1 - Ring J1 (not used in Synth applications)
5. VP2 - Tip J2
6. VR2 - Ring J2 (not used in Synth applications)
7. GND
8. GND

Build Options

• D1-D3 = Clamping diodes
• R1, R2 = Series resistor
• R3, R4 - scaling resistors
• C1, C2 - Parallel capacitor
• J3, 1x4 or 2x4 (above)

Build as Adapter (No SCF)

• Just install 0 Ohms series resistor at R1, R2

Build as Buffered Connection

• Install series resistors at R1, R2

Build as Filter Without Clamping

• R1/C1 filter
• R2/C2 filter

Mechanicals