1458 Optocoupler Datasheet Link

If you have a component mislabeled as a "1458 optocoupler" in your BOM, here is what it is actually used for:

| Parameter | Symbol | Conditions | Min | Typ | Max | Unit | |-----------|--------|------------|-----|-----|-----|------| | Rise time | ( t_r ) | - | - | 4 | 18 | µs | | Fall time | ( t_f ) | - | - | 3 | 18 | µs | | Turn-on time | ( t_on ) | - | - | 6 | - | µs | | Turn-off time | ( t_off ) | - | - | 5 | - | µs |

Note: Switching times vary with load resistor and transistor biasing.

| Parameter | Symbol | Rating | Unit | |-----------|--------|--------|------| | Forward Current (LED) | I_F | 60 | mA | | Reverse Voltage (LED) | V_R | 6 | V | | Collector-Emitter Voltage | V_CEO | 30 | V | | Emitter-Collector Voltage | V_ECO | 7 | V | | Power Dissipation (Output) | P_out | 150 | mW | | Total Package Dissipation | P_tot | 250 | mW | | Isolation Test Voltage | V_ISO | 5000 | V_RMS | 1458 optocoupler datasheet

Key Insight: Exceeding I_F = 60mA degrades the LED. The isolation voltage (5 kV_RMS) is the primary advantage over non-isolated solutions.

| Parameter | Symbol | Rating | Unit | | :--- | :---: | :---: | :---: | | Input (Emitter) | | | | | Forward Current | $I_F$ | 50 | mA | | Peak Forward Current | $I_FM$ | 1.0 | A | | Reverse Voltage | $V_R$ | 6 | V | | Output (Detector) | | | | | Collector-Emitter Voltage | $V_CEO$ | 35 - 80* | V | | Emitter-Collector Voltage | $V_ECO$ | 6 | V | | Collector Current | $I_C$ | 50 | mA | | Total Device | | | | | Isolation Voltage | $V_ISO$ | 5000 | Vrms | | Operating Temperature | $T_opr$ | -30 to +100 | °C | | Storage Temperature | $T_stg$ | -55 to +125 | °C |

Note: $V_CEO$ varies significantly by manufacturer; always verify the specific brand. If you have a component mislabeled as a

This table is non-negotiable. Exceed these values, and you release the magic smoke.

| Parameter | Symbol | Typical Value (4N35) | | :--- | :--- | :--- | | Forward Current (LED side) | IF | 60 mA | | Reverse Voltage (LED) | VR | 6 V | | Collector-Emitter Voltage | VCEO | 30 V | | Emitter-Collector Voltage | VECO | 7 V | | Power Dissipation (Output) | PC | 150 mW | | Operating Temperature | TOPR | -55°C to +100°C |

Expert Note: If your "1458 optocoupler" has a VCEO lower than 30V, it is not suitable for motor drives. If it is higher (e.g., 70V), it is likely a high-voltage variant like the 4N36. | Parameter | Symbol | Rating | Unit

Since no "1458 optocoupler" exists, we analyze the widely available 4N35 from Vishay or ON Semiconductor.

Note: There is no industry-standard optocoupler with the primary designation "1458." The "1458" is famously a dual operational amplifier (e.g., LM1458, UA1458). This paper addresses that ambiguity, clarifies the likely confusion, and provides a rigorous methodological framework for analyzing an optocoupler datasheet, using a real, similar device (e.g., 4N35) as a practical example.