The HCPL-1458 (also referred to as the A1458) is a high-speed, logic-gate optocoupler primarily manufactured by Broadcom (formerly Avago/Agilent). It is designed to provide high-speed signal isolation between a circuit's input and output, protecting sensitive low-voltage components from high-voltage transients. Key Technical Specifications
The HCPL-1458 is characterized by its high common-mode rejection and speed, making it suitable for demanding industrial environments. Typical Value Description Data Rate Maximum signal transmission speed Propagation Delay 4 µs (typical) Signal delay time from input to output Isolation Voltage 3750 Vrms to 5300 Vrms Maximum rated isolation Operating Voltage (Vcc) 4.5 V to 5.5 V Standard logic-level supply voltage Operating Temperature -40°C to +85°C Range for industrial applications Current Transfer Ratio 60% (minimum) Ratio of output current to input current Pinout Configuration
The HCPL-1458 is typically housed in an SOP-8 or DIP-8 package. While specific internal diagrams vary by variant, a standard high-speed 8-pin optocoupler often follows this general layout:
Pin 1 & 4: Usually NC (No Connection) or specific anode/cathode pins. Pin 2: Anode (Input LED). Pin 3: Cathode (Input LED). Pin 5: GND (Output side). Pin 6: Vout (Output Signal). Pin 7: NC or Enable. Pin 8: Vcc (Supply Voltage). Common Applications
Industrial Control Systems: Maintaining electrical isolation between microcontrollers and high-power industrial equipment. 1458 optocoupler datasheet
Switch-Mode Power Supplies (SMPS): Used in feedback loops to safely transmit regulation signals across isolation barriers.
Motor Drive Circuits: Protecting low-voltage control systems from the high voltages used in AC or DC motor drives.
Renewable Energy: Isolation in solar inverters and wind turbine controllers. Important Note on the "1458" Part Number
In the electronics industry, "1458" is also a very common designation for the MC1458 or LM1458. However, these are Dual Operational Amplifiers, not optocouplers. If your component is an 8-pin IC used for signal amplification rather than isolation, you are likely looking for the MC1458 Datasheet. MC1458 - STMicroelectronics The HCPL-1458 (also referred to as the A1458
The output side contains a phototransistor that switches on when it detects IR light.
How do you actually use this? Here is a classic example of interfacing a 5V microcontroller with a 12V load.
The Goal: Turn on a 12V relay using a 5V Arduino.
In this setup, when the Arduino sends a HIGH signal, the internal LED lights up. The phototransistor detects this light and closes the circuit, allowing the 12V current to flow through the relay. The Arduino remains electrically isolated from the 12V circuit. use dedicated logic optocouplers (e.g.
Author: Technical Analysis Division Date: October 2023
| Parameter | Symbol | Value (Typical) | Unit | |-----------|--------|----------------|------| | Rise Time | t_r | 2 | µs | | Fall Time | t_f | 2 | µs | | Turn-on Time | t_on | 3 | µs | | Turn-off Time | t_off | 3 | µs |
Note: Standard optocouplers like the 4N35 are slow (µs range). They cannot pass high-speed data (e.g., I²C at 400 kHz or SPI at 10 MHz). For high speed, use dedicated logic optocouplers (e.g., 6N137).