4N33 Optocoupler Photodarlington Output High Gain DIP-6
The 4N33 is an optically coupled isolator that pairs a gallium arsenide infrared LED with a silicon photodarlington sensor. It converts light from the input LED into a proportional electrical response at the photodarlington, allowing a drive circuit to control a separated load circuit without direct electrical connection. This optical link preserves signal integrity while preventing ground loops and reducing interference between sections of a system.
Inside the device, the photodarlington stage amplifies the photocurrent generated by the LED, producing an output current and voltage sufficient to drive subsequent circuitry. The intrinsic high-gain behavior of the photodarlington makes the part easy to interface, minimizing the need for extra amplification stages in many designs. Signal transitions are handled with predictable propagation characteristics so it can be used where controlled switching is required.
Encapsulated in a compact, standard plastic DIP-6 package, the 4N33 supports conventional through-hole assembly and straightforward PCB layout. The physical separation between LED and detector, along with insulating materials, provides electrical isolation that helps protect sensitive electronics and users from unwanted voltages. Overall, the 4N33 offers a simple, robust way to achieve electrical isolation with an optically mediated switching element and reliable operation.
Features:
- Very high current transfer ratio (≥ 500 % min).
- High isolation resistance (typical 10¹¹ Ω).
- Standard plastic DIP package (DIP-6).
Specifications:
| Parameter | Value |
|---|---|
| Input reverse voltage (VR): | 3 V |
| Input forward current (IF, absolute max): | 60 mA |
| Input forward voltage (VF, IF = 50 mA): | 1.25 V |
| Collector-Emitter breakdown (BVCEO): | 30 V |
| Collector (load) current, max (IC): | 100 mA |
| Collector-Emitter saturation voltage (VCE(sat)): | 1 V |
| Current Transfer Ratio (CTR, IF = 10 mA, VCE = 10 V): | ≥ 500 % |
| Turn-on time (ton, VCC = 10 V, IC = 50 mA): | ≤ 5 µs |
| Turn-off time (toff, IF = 200 mA, RL = 180 Ω): | ≤ 100 µs |
| Isolation test voltage (VISO): | 5300 VRMS |
| Isolation resistance (VIO = 500 V, 25 °C): | ≥ 10¹² Ω |
| Operating temperature (Tamb): | −55 to +100 °C |
Pinout:
Footprint:
Applications:
- Replacement for reed relays.
- Replacement for mercury relays.
Package Contents:
- 1x 4N33 Optocoupler Photodarlington Output High Gain DIP-6