A1458 Optocoupler Datasheet [best] May 2026

However, based on common optocoupler naming conventions and visual similarities, here are the three most likely components you might be looking for, along with a summary of their datasheets:

Common Failure Modes and Troubleshooting

Based on field application notes from the datasheet, here are common issues:

  1. Output stuck LOW:

    • Cause: LED always on (shorted driver or missing resistor).
    • Fix: Verify voltage across LED (should be ~1.2V). Check if current limit resistor is present.

  2. Output stuck HIGH:

    • Cause: LED open circuit or phototransistor damaged.
    • Fix: Measure forward voltage on input. If >1.4V at 10mA, the LED may be open. Replace unit.

  3. Slow or erratic switching:

    • Cause: Pull-up resistor too high (e.g., 100kΩ).
    • Fix: Reduce to 10kΩ or lower. Check for stray capacitance on output node (>50pF will degrade speed).

  4. Reduced CTR after soldering:

    • Cause: Excessive heat during reflow soldering.
    • Fix (from datasheet reflow profile): Peak temperature ≤260°C for ≤10 seconds.

6. Electrical Characteristics (Ta = 25°C)

| Parameter | Symbol | Test Condition | Min | Typ | Max | Unit | |--------------------------|--------|-------------------------|-----|-----|-----|-------| | LED forward voltage | VF | IF = 20 mA | 1.1 | 1.2 | 1.4 | V | | LED reverse current | IR | VR = 6 V | - | - | 10 | µA | | Collector dark current | ICEO | VCE = 20 V, IF = 0 | - | - | 100 | nA | | Current transfer ratio | CTR | IF = 5 mA, VCE = 5V | 50 | 300 | 600 | % | | Collector-emitter sat. | VCE(sat)| IF = 10 mA, IC = 2 mA | - | 0.2 | 0.4 | V | | Isolation resistance | RISO | VIO = 500 Vdc | 10¹¹| - | - | Ω | | Capacitance (input-output)| CIO | f = 1 MHz | - | 1.0 | - | pF | a1458 optocoupler datasheet

Part 8: Layout and Design Guidelines

Based on recommendations in the A1458 optocoupler datasheet and industry best practices:

  1. Keep Input and Output Separate: Do not route high-voltage or noisy traces under the optocoupler. Maintain a physical and electrical gap.
  2. Creepage on PCB: On the PCB, ensure at least 4 mm clearance between input-side copper and output-side copper (more for >250V applications).
  3. Slotted PCB: For high isolation (>5kV), consider a slot in the PCB under the optocoupler.
  4. Bypass Capacitors: Place a 0.1 μF ceramic capacitor near the output VCC and ground (if using external pull-up) to reduce switching noise.
  5. Current Limit: Never drive the LED directly from a voltage source without a series resistor. A small change in voltage leads to a large change in current – potentially destructive.