MIL-STD-1553B DATA BUS COUPLER
Vibran Technologies offers MIL-STD-1553B compliant Data Bus Couplers designed for defence, aerospace, and mission-critical embedded applications.
A Data Bus Coupler is a small interface module used to connect each Remote Terminal or Node to the main data bus while protecting the bus from faults. It includes Bus-In and Bus-Out lines for the main bus and one or more stub ports that connect to equipment.
Each stub uses a coupling transformer and two isolation resistors, which help maintain the correct bus impedance, reduce signal reflections, and provide electrical isolation. This design ensures that if a stub or terminal becomes shorted or fails, the main bus continues to work normally without interruption.
Couplers with connectors attached directly into the housing are called connectorized Data Bus Couplers, offering simpler installation and better reliability. Overall, VIBRAN couplers ensures clean signal transmission, proper impedance matching, and fault protection for the entire data bus system.
| Parameter | Description |
|---|---|
| Transformer Turns Ratio | 1:1.41 (with ±3%) as per MIL-T-21038 |
| Transformer Common Mode Rejection(CMR) | > 55dB @ 1MHz with 10VRMS as per MIL-T-21038 |
| Transformer Open Circuit Impedance (75 kHz to 1 MHz) | |Z| > 10 kΩ min at 25°C as per MIL-T-21038 |
| Transformer Waveform Integrity (Droop) | 20% max (250 kHz square wave with 90ns±5%) maximum rise and fall time) as per MIL-T-21038 |
| Isolation Resistors in series | 59 Ω with ± 1% |
| Insulation resistance (Winding to Winding) | Ri > 1000 MΩ with a 250 VDC test voltage |
| Overshoot and Ringing | ±1.0V Peak (250 kHz square wave with 100 ns max rise and fall time) as per MIL-T-21038 |
| Stub Voltage | 1Vpp to 14Vpp (Transformer Coupled) |
| Transformer Primary DC Resistance | < 2.7 Ω as per MIL-T-21038 |
| Transformer Secondary DC Resistance | < 2 Ω as per MIL-T-21038 |
| Primary Parallel Inductance | > 40mH |
| Primary Shunt Capacitance | < 35pF |
| Inter Winding Capacitance | < 45pF |
| Primary Leakage inductance | < 6μH |
| Shield continuity | < 100mΩ |
| Termination | 78Ω ±2%, 1W (Optional) |
| Insulation Resistance |
> 1000 MW at 250 VDC (Bus/Stub) > 1000 MW at 500 VDC (Inner contacts/Shield) |
| Connector Type | BJ77 (Jack type/socket contact Bayonet coupled-Triax) |
| Operating Temperature | -50°C to +125°C |
| Storage Temperature | -50°C to +125°C |
| Body Case | Aluminium 6061 with Black Anodization |
| Coupler Module |
Encapsulated with the following components --> Coupler Transformer to MIL-T-21038 --> Fault protection Resistors to MIL-R-39007 |
| Weight |
VT 1002 <110 grams (2-Stub) VT 1004 < 180grams (4-Stub) |
Note: The cost between 1 & 2 and 3 & 4 stub couplers is negligible, hence we don’t manufacture 1 & 3 stub couplers.