The Dow-Key Microwave 401R-3908 is a high-performance electromechanical coaxial SPDT switch engineered for RF and microwave test, measurement, and communications applications. Operating across DC to 40 GHz, this 50 Ohm switch delivers low insertion loss, exceptional isolation, and switching times of 15 ms maximum. Available in latching or failsafe configurations with multiple coil voltage options, the 401R-3908 withstands one million mechanical cycles minimum and operates reliably across -25°C to +65°C.
## Technical Specifications
• **Frequency Range:** DC to 40 GHz
• **Impedance:** 50 Ohm
• **Configuration:** Single Pole Double Throw (SPDT), electromechanical coaxial
• **Switching Time:** 15 ms maximum
• **Coil Voltage Options:** 12 Vdc (11–14 Vdc), 15 Vdc, 24 Vdc (20–32 Vdc), 28 Vdc (24–32 Vdc)
• **Coil Current (max @ nominal Vdc, 25°C):** 230 mA at 12 Vdc; 135 mA at 24 Vdc; 115 mA at 28 Vdc
• **Operating Temperature:** -25°C to +65°C standard; -55°C to +85°C extended range available
• **Vibration (Operating):** 10 G RMS, 20–2000 Hz
• **Mechanical Shock (Non-Operating):** 30 G, 1/2 Sine, 11 ms
• **Mechanical Life Cycles:** 1,000,000 minimum; 5,000,000 minimum with “U” option
• **Weight:** 1.4 oz (40 g) standard latching model
## Key Features
• Insertion loss from 0.10 dB (DC–1 GHz) to 0.50 dB (18–26.5 GHz)
• Isolation performance ranging 85 dB (DC–1 GHz) to 55 dB (18–26.5 GHz)
• VSWR maximum from 1.10 (DC–1 GHz) to 1.50 (18–26.5 GHz)
• SMA or 2.92 mm (K) connector options
• Configurable circuit options including TTL High, TTL Low, and suppression diodes
• Available with or without indicators
## Typical Applications
Test and measurement systems, communication infrastructure, aerospace and defense platforms requiring rapid RF signal routing with minimal phase distortion.
## Compatibility & Integration
Part of the 401 Series platform offering customizable configurations for voltage, temperature, connector type, and circuit topology to match specific system requirements.
