Many A1458 variants carry UL 1577, VDE 0884 (reinforced insulation), and CSA approvals. Always check the specific datasheet for regulatory marks if your design requires safety certification. Part 7: Typical Application Circuits (From Datasheet Examples) The A1458 optocoupler datasheet often includes reference circuits. Here are two common ones. Circuit 1: Digital Logic Isolation (High → Low) Scenario: Isolating a 24V PLC output to a 3.3V microcontroller input.
For digital logic interfaces (e.g., 5V to 3.3V), ranks A or B are sufficient. For analog applications or low I_F drive (e.g., 1 mA from a battery-powered MCU), ranks C or D provide higher sensitivity. Part 5: Switching Characteristics (Speed) The A1458 is not an ultra-high-speed device (like a logic gate optocoupler, e.g., 6N137), but it is adequate for most power supply feedback and low-speed data isolation (< 50 kHz). a1458 optocoupler datasheet
| Parameter | Symbol | Conditions | Value | Unit | |-----------|--------|-------------|-------|------| | Isolation Voltage | V_ISO | Ta=25°C, 60Hz, 1 sec | 5,000 | Vrms | | Isolation Resistance | R_IO | V_IO = 500V | 10^12 (min) | Ω | | Isolation Capacitance | C_IO | V_IO = 0V, f=1MHz | 0.8 (typ) | pF | Many A1458 variants carry UL 1577, VDE 0884
| Parameter | Symbol | Conditions | Typ | Max | Unit | |-----------|--------|-------------|-----|-----|------| | Rise Time | t_r | V_CE = 2V, I_C = 2mA, R_L = 100Ω | 4 | 18 | μs | | Fall Time | t_f | Same as above | 3 | 18 | μs | | Turn-On Time | t_on | I_F = 10 mA to I_C = 2mA | 5 | 20 | μs | | Turn-Off Time | t_off | Same | 4 | 20 | μs | Here are two common ones
| Model | CTR (%) | V_CEO (V) | t_on/t_off (μs) | Isolation (Vrms) | Best For | |-------|---------|-----------|-----------------|------------------|-----------| | | 50-600 | 80 | 5/4 | 5,000 | General purpose, wide CTR | | PC817 | 50-600 | 35 | 4/3 | 5,000 | SMPS feedback (lower V_CEO) | | 4N35 | 100 (min) | 30 | 10/10 | 5,000 | Hobbyist, older designs | | 6N137 | - (logic) | 7 | 0.075 | 5,000 | High-speed data (10 Mbps) |
Inside the package, pin 1 connects to the LED’s anode, pin 2 to its cathode. The phototransistor sits with its collector on pin 4 and emitter on pin 3. There is no base pin exposed; base current is generated solely by illumination.