Fototransistor-optocoupler Broadcom HCPL-2730-000E DIP-8 Darlington DC

Broadcom HCPL-2730-000E is a DIP-8 phototransistor optocoupler with a Darlington output stage engineered for galvanic isolation of DC signals. The device separates the input LED from the phototransistor output to provide reliable electrical isolation between low-voltage control circuitry and the isolated side. It is intended for interfacing logic-level signals, microcontroller inputs, and other low-speed digital lines where DC isolation and input-to-output protection are required.

Advantages

The Darlington output configuration delivers higher current gain than a single transistor, enabling stronger output drive for downstream logic or pull-down requirements while maintaining low input LED current. The DIP-8 package supports easy through-hole mounting for prototyping and legacy circuit designs. The optocoupler provides stable performance for low-frequency digital isolation and reduces the risk of ground loops by preserving galvanic separation between circuits.

Suitable for

• Isolation of microcontroller digital inputs and outputs
• Signal level translation between different logic domains
• Power-supply feedback and control loop isolation
• Industrial control interfaces with low-speed digital signals

Key specifications

• Package: 8-pin DIP (through-hole)
• Output type: Phototransistor with Darlington configuration
• Function: DC signal isolation / low-speed digital isolation
• Input: Infrared LED drive required; low input current operation
• Isolation: Galvanic isolation between input LED and output transistor
• Mounting: Through-hole PCB mounting

How to use

Place the device in a through-hole footprint on the PCB following correct pin orientation for input LED and output transistor pins. Drive the input LED from the control side with an appropriate current-limiting resistor sized to the required LED drive current. On the isolated side, connect the phototransistor output to the target logic or pull-up/pull-down network according to the required logic levels. Observe recommended absolute maximum ratings for input current and output voltage when designing the surrounding circuit to ensure reliable isolation and long-term operation.

Recommendations

For reliable operation, use a suitable current-limiting resistor on the input LED and verify that the output pull-up or pull-down network matches the expected logic thresholds. Allow for proper creepage and clearance distances on the PCB to maintain the isolation rating, and avoid exposing the device to temperatures or voltages beyond its specified limits.