Herotek S2S0518A4 0.5–18GHz SPDT PIN Diode Switch
The Herotek S2S0518A4 is a broadband SPDT PIN diode switch designed to route RF and microwave signals between two output paths over the 0.5–18GHz frequency range.
It combines wideband operation, 40dB minimum isolation and 100ns typical switching speed in a connectorized module with removable SMA connectors. The S2S0518A4 does not include an integral driver and is suitable for systems that already provide the required external PIN diode control current.
S2S0518A4 Specifications
| Parameter | Specification |
| Manufacturer | Herotek |
| Model | S2S0518A4 |
| Product Type | SPDT PIN Diode RF Switch |
| Switch Configuration | Single Pole Double Throw |
| Frequency Range | 0.5–18GHz |
| Maximum Insertion Loss, 0.5–2GHz | 1.3dB |
| Maximum Insertion Loss, 2–8GHz | 1.6dB |
| Maximum Insertion Loss, 8–18GHz | 2.2dB |
| Minimum Isolation | 40dB |
| Maximum VSWR | 2.0:1 |
| Typical Switching Speed | 100ns |
| Maximum Average Input Power | 1W |
| Isolation Port Type | Reflective |
| Integral Driver | No |
| RF Connectors | Removable SMA female |
| Operating Temperature | −55°C to +125°C |
| Storage Temperature | −65°C to +125°C |
S2S0518A4 vs S2D0518A4
The S2S0518A4 and S2D0518A4 have the same RF frequency range, insertion-loss limits, isolation and VSWR. The difference is the control configuration.
| Model | Frequency | Isolation | Integral Driver | Recommended Use |
| S2S0518A4 | 0.5–18GHz | 40dB minimum | No | System already has a PIN diode driver |
| S2D0518A4 | 0.5–18GHz | 40dB minimum | Yes | TTL-controlled system requiring an integrated driver |
The S2D0518A4 uses TTL control with external positive and negative DC supplies, while the S2S0518A4 requires direct current control.
Alternative Isolation Options
Herotek also lists higher-isolation versions within the same 0.5–18GHz family:
| Model | Minimum Isolation | Maximum Insertion Loss at 8–18GHz | Integral Driver |
| S2S0518A4 | 40dB | 2.2dB | No |
| S2S0518A5 | 55dB | 2.5dB | No |
| S2S0518A6 | 60dB | 3.0dB | No |
The S2S0518A4 offers the lowest insertion loss of these three non-driver models. The A5 and A6 versions provide higher isolation but introduce additional loss, particularly at higher frequencies.
Selection Considerations
The S2S0518A4 is a practical choice when the design requires:
Broadband switching from 500MHz to 18GHz
SPDT routing between two microwave signal paths
At least 40dB isolation
Switching speed around 100ns
Up to 1W average input power
External control rather than an integrated TTL driver
Removable connectors for drop-in installation
Before ordering, confirm the required isolation, insertion-loss budget, RF power, control-current capability and whether reflective isolated ports are acceptable.
Ordering Information
DataStorageIC supports international inquiries for the Herotek S2S0518A4 and related PIN diode switches, including:
S2S0518A4 price and lead-time confirmation
Datasheet and technical specification requests
S2S0518A4 versus S2D0518A4 selection
Higher-isolation A5 and A6 alternatives
International quotations and delivery support
Please provide the required quantity, destination country, target delivery date and control-interface requirements when requesting a quote.
Frequently Asked Questions
What frequency range does the Herotek S2S0518A4 cover?
The S2S0518A4 operates from 0.5GHz to 18GHz.
Does the S2S0518A4 include an integral driver?
No. It requires an external control circuit providing approximately ±40mA control current. The S2D0518A4 is the corresponding version with an integral driver.
What is the isolation of the S2S0518A4?
Herotek specifies a minimum isolation of 40dB across the operating frequency range.
What is the maximum insertion loss?
Maximum insertion loss is 1.3dB from 0.5–2GHz, 1.6dB from 2–8GHz and 2.2dB from 8–18GHz.
Is the S2S0518A4 absorptive or reflective?
It is a reflective SPDT switch. The isolated RF port is not internally terminated.
What input power can the switch handle?
Herotek specifies a maximum average input power of 1W.
