Difference between revisions of "OPTOFAST-2"
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*** That is 26 mA (in the switching range of the transistor) | *** That is 26 mA (in the switching range of the transistor) | ||
* H1 do not short | * H1 do not short | ||
| + | |||
| + | === Direct Drive - Special Option === | ||
| + | |||
| + | [[File:OPTOFAST-2-Schematic-Direct.PNG]] | ||
| + | |||
| + | * Do not install Q1 | ||
| + | * Do not install R1 | ||
| + | * R2 = 150 | ||
| + | ** Input current = LED current = 3.5V/150 Ohms = 23 mA | ||
| + | * Do not install R3 | ||
| + | * Do not install Q1 | ||
| + | * Short H1 | ||
| + | |||
| + | == Output Options == | ||
| + | |||
| + | === Standard Output === | ||
| + | |||
| + | * R17 = 1.2K | ||
| + | ** 5V/1.2K = 4.1mA of output transistor B-E current | ||
| + | ** Leaves 4.7-4.1 mA = 600 uA of output low current | ||
| + | |||
| + | === Open Collector Output - Special Option === | ||
| + | |||
| + | * Do not install R17 | ||
| + | |||
| + | === Fast Option - Standard === | ||
| + | |||
| + | * R13 = 20K (empirically determined from the scope eye) | ||
| + | |||
| + | == Connectors == | ||
| + | |||
| + | === P1 - Input === | ||
| + | |||
| + | 8-pin, right angle, 0.1" pitch | ||
| + | |||
| + | # Vcc (In) | ||
| + | # Vcc (In) | ||
| + | # IN 1 | ||
| + | # IN 2 | ||
| + | # IN 3 | ||
| + | # IN 4 | ||
| + | # GND (In) | ||
| + | # GND (In) | ||
| + | |||
| + | === P2 - Output === | ||
| + | |||
| + | 8-pin, right angle, 0.1" pitch | ||
| + | |||
| + | # Vcc (Out) | ||
| + | # Vcc (Out) | ||
| + | # OUT 1 | ||
| + | # OUT 2 | ||
| + | # OUT 3 | ||
| + | # OUT 4 | ||
| + | # GND (Out) | ||
| + | # GND (Out) | ||
Revision as of 00:00, 10 January 2020
Contents
Features
- Opto-Isolator card
- 4-Channels
- 4N25 Optoisolators
- Input /Output isolation
- Transistor driver for Opto LED reduces required drive from 10 mA to under 500 uA
- Input channels share their own common VCC/Ground
- Output channels share their own common Vcc/Ground
- 8-pin header for input
- 8-pin header for output
- Configuration Options
- Speed enhanced
- Bypass Input transistors
- Remove Output collector resistors
- 49x49mm
- (4) 4-40 mounting holes
Schematic (One channel)
- U1 represents U1-U4 (channels 1-4)
- Q1 represents Q1-Q4 (channels 1-4)
- R1 (VCC) represents R1,R4,R7,R10 (channels 1-4)
- R2 (DIR) represents R2,R5,R8,R11 (channels 1-4)
- R3 (BASE) represents R3,R6,R8,R12 (channels 1-4)
- R13 (FAST) represents R13-R16 (channels 1-4)
- R17 (COLL) represents R17-R20 (channels 1-4)
Input Options
- Refer to schematic for impact of options
Use Input Transistor - Standard Option
- Common VCC in option
- Install transistor Q1
- R1 = 150
- LED current is 3.5V/150 Ohms = 23 mA
- CTR = .20, 4.7 mA
- R2 = Do not populate
- R3 = 10K
- Base drive ~ (Vin - 0.7V)/R3
- At 5V drive this is 4.3V/R3
- Using R3=10K at 5V this is 0.43mA Ib
- HFE (MMBT3904) = 100 min
- That is potentially 43 mA (in the switching range of the transistor)
- Collector resistor and LED voltage drop are current limiter
- At 3.3V drive this is (3.3-0.7)/10K = .26mA Ib
- HFE = 100 min
- That is 26 mA (in the switching range of the transistor)
- H1 do not short
Direct Drive - Special Option
- Do not install Q1
- Do not install R1
- R2 = 150
- Input current = LED current = 3.5V/150 Ohms = 23 mA
- Do not install R3
- Do not install Q1
- Short H1
Output Options
Standard Output
- R17 = 1.2K
- 5V/1.2K = 4.1mA of output transistor B-E current
- Leaves 4.7-4.1 mA = 600 uA of output low current
Open Collector Output - Special Option
- Do not install R17
Fast Option - Standard
- R13 = 20K (empirically determined from the scope eye)
Connectors
P1 - Input
8-pin, right angle, 0.1" pitch
- Vcc (In)
- Vcc (In)
- IN 1
- IN 2
- IN 3
- IN 4
- GND (In)
- GND (In)
P2 - Output
8-pin, right angle, 0.1" pitch
- Vcc (Out)
- Vcc (Out)
- OUT 1
- OUT 2
- OUT 3
- OUT 4
- GND (Out)
- GND (Out)
