2.2.2
Summary Description
NEXSYS Solid State Relays are available individually (SSR), Series A (4 Pin), or in a combination of four (SSRCH), Series C (8 Pin), see Figure 2.2.2.0-A and Figure 2.2.2.0-B. The Solid-State Relays perform custom digital and analog signal control, as well as audio and data signal switching. The broad operating voltage range affords use in numerous applications from simple polarity reversal to logic gate functions like AND, OR, and BUFFER. The Solid-State Relays perform similar functions to a stand-alone mechanical relay without the challenges of external packaging. While Solid State Relays include the advantages of a solid-state design with opto-isolation, high reliability, and low power consumption.
The Solid State Relays feature an integrated electronic circuit to perform signal buffering, optical isolation, and surge-suppression between inputs and outputs, eliminating possible sneak paths. The NEXSYS Solid State Relay (SSR1, SSR2, SSR3, SSRC) is a commercial-off-the-shelf (COTS) item. This standard catalog hardware includes features to allow for flexible interface design solutions while also meeting aircraft performance standards. The SSR is designed, tested, and qualified to MIL-PRF-22885/116, MIL-PRF-22885/117, DO-160 and MIL-STD-461 requirements. Specifications are available in our MIL-PRF and DO-160 Documents page, and the qualification table is available in Appendix A.
Input Characteristics
NEXSYS Solid State Relays have two control bridge types. The SSR1, SSR2, and SSRC have a bidirectional control bridge which allows DC voltages to be applied in either direction for polarity insensitive design flexibility. The SSR3H has a unidirectional control buffer, which is ideal for applications where current flow is only required in one direction. The SSR3H input circuitry is diode isolated and buffered for reliable operation. The SSRs are available in multiple operating voltages for custom switching control, as indicated below. See additional sections for specific details concerning the Input/Output (I/O) interface.
IN (PIN 2, 3), Single SSR1 and SSR2: High (H) 28V (Nom.), 6.3 mA (Nom.); Mid (M) 14V (Nom.), 6.2 mA (Nom.); and Low (L) 5V (Nom.), 12.1 mA (Nom.).
IN (PIN 2, 3), Single SSR3H: High (H) 28V (Nom.), 10 mA (Nom.), 8V (Min.), 7 mA (Nom.).
Note: PIN 2 and 3 are polarity sensitive. PIN 2 is for (+) input and PIN 3 is for (-) input.
IN (PIN 4, 5), Combination SSR: High (H) 28V (Nom.) 25 mA (Max).
Output Characteristics
NEXSYS Solid State Relays feature isolated Switch (SW) outputs to perform functions that may originate from remote inputs or switch closures. Solid State Relay switch outputs are fused and surge-protected against transients and overload conditions, see Figure 2.2.2.3-A (Operating Parameters) for electrical load rating types.
SW (PIN 1, 4), Single SSR1 and SSR2: SPST, Normally-Open (SSR1), and Normally-Closed (SSR2).
SW (PIN 1, 4), Single SSR3H: SPST, Normally-Open (NO). PIN 1 and 4 are polarity sensitive. PIN 1 is for (+) input and PIN 4 is for (-) input. DC Voltage only.
SW/COM (PIN 1, 2, 3, 8, 7, 6), Combination SSRCH: Four SPST, Normally-Open (1) and Normally-Closed (2).
Configuration Options
NEXSYS Solid State Relays are specified individually (SSR), or in a combination of four (SSRCH). The SSRCH configuration is internally connected to reduce external splices and to perform synchronized switching. SSRs power-up in a known state, either Normally-Open (SSR1 & SSR3H) or Normally-Closed (SSR2). With operating voltage applied across the inputs, the Normally-Open (NO) SPST switch closes to conduct the connected signal, and the Normally-Closed (NC) SPST switch opens. The following configuration options are available for Single (SSR) SSRs, including SSR1, SSR2, and SSR3H.
2.2.2.1 Single (SSR)
Single SSR: Series A (4 Pin) single SSRs are available in Normally-Open (SSR1 & SSR3H) and Normally-Closed (SSR2) versions. SSR1 and SSR2 have three nominal input voltage options; Low (+5 VDC), Mid (+14 VDC), and High (+28 VDC). SSR3H is exclusively available with a nominal input voltage of +28 VDC.
The current draw of the three voltage options for SSR1 and SSR2 is 12.1 mA (+5 VDC), 6.2 mA (+14 VDC), and 6.3 mA (+28 VDC), see Figure 2.2.2.1-A. The current draw for SSR3H is 10 mA (+28 VDC).
Normally Open (NO): 0.75 A (Resistive) max output load capacity*
SSR1H: Normally-Open (NO) SPST Closes when +18 to 32 VDC is applied across the inputs.
SSR1M: Normally-Open (NO) SPST Closes when +8 to 18 VDC is applied across the inputs.
SSR1L: Normally-Open (NO) SPST Closes when +4 to 6 VDC is applied across the inputs.
Normally Closed (NC): 0.25 A (Resistive) maximum output load capacity*
SSR2H: Normally-Closed (NC) SPST Opens when +18 to 32 VDC is applied across the inputs.
SSR2M: Normally-Closed (NC) SPST Opens when +8 to 18 VDC is applied across the inputs.
SSR2L: Normally-Closed (NC) SPST Opens when +4 to 6 VDC is applied across the inputs.
High Current Normally Open (NO): 5 A (Resistive) maximum output load capacity**
SSR3H: Normally-Open (NO) SPST Closes when +8 to +32 VDC is applied across the IN+ and IN- inputs.
*The outputs switch up to +32 VDC or 28 VAC (VRMS) and are surge-protected against transients and overload conditions via a Very Fast Acting fuse.**The output switches up to +32 VDC and is surge-protected against transients and overload conditions via a Very Fast Acting fuse.
Signal Description
For a description of the input and output functions of the Single SSR (SSR1 & SSR2) component, see Figure 2.2.2.1-B (SSR3H) see Figure 2.2.2.1-C.
| Signals | Pins | Normally Open (NO) Logic Functions SSR1H, SSR1M & SSR1L |
Normally Closed (NC) Logic Functions SSR2H, SSR2M & SSR2L |
Comments |
| IN | 2 & 3 | Input: Active when DC voltage applied across PINS 2 and 3. |
DC Voltage can be applied in either direction. See Note 1. |
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| SW | 1 & 4 | Output: Conductive between pins 1 and 4 in either polarity when Input is active. Output is high impedance when input is off. | Output: High impedance between pins 1 and 4 when Input is active. Output is conductive in either polarity when input is off. | Approx. 0.5 volt drop at 0.75 A load between pins 1 and 4 when conducting. See Note 2. |
| Notes | ||||
| Signals | Pins | Normally Open (NO) Logic Functions SSR3H |
Comments |
| IN + | 2 | Input: Active when positive DC voltage applied across PINS 2 and 3. |
DC Voltage only +32 VDC Max |
| IN - | 3 | ||
| OUT + | 1 | Output: Conductive from pins 1 and 4 when Input is active. | Output is polarity sensitive. Applying current in the reverse direction can destroy the output driver. |
| OUT - | 4 | ||
| Notes | |||
2.2.2.2 Combination (SSRC)
Combination SSRCH: The output load capacity ratings of the Normally-Open (NO) and Normally-Closed (NC) SSRCH configurations and the switch logic performs identically to the Single SSR. However, the internal connections differ in three switching options with multiple combinations of NO (denoted by a 1) and NC (denoted by a 2) switch contacts; see Figure 2.2.2.2-A, Figure 2.2.2.2-C, and Figure 2.2.2.2-E. The most common configurations are listed below in the tables in bold text; see Figure 2.2.2.2-B, Figure 2.2.2.2-D, and Figure 2.2.2.2-F.
Four Switch, Single Common: Four (4) SPST contacts, configured with a single, internally spliced common, see Figure 2.2.2.2-A and Figure 2.2.2.2-B.
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| Configuration (SSRCH/ABCD) | Common A & B, internally spliced |
| SSRCH/1111 | 4 NO SPST |
| SSRCH/2222 | 4 NC SPST |
| SSRCH/1122 | 2 NO and 2 NC SPST, grouped |
| SSRCH/1212 | 2 NO and 2 NC SPST, collated |
| SSRCH/2121 | 2 NC SPST and 2 NO SPST, collated |
| SSRCH/1112 | 3 NO SPST, grouped and 1 NC SPST |
| SSRCH/1121 | 1 NC SPST between 3 NO SPST |
| SSRCH/1211 | 1 NC SPST between 3 NO SPST |
| SSRCH/1221 | 2 NO SPST, split and 2 NC SPST, grouped |
| SSRCH/1222 | 1 NO SPSTand 3 NC SPST, grouped |
| SSRCH/2111 | 1 NC SPSTand 3 NO SPST, grouped |
| SSRCH/2112 | 2 NC SPST, split and 2 NO SPST, grouped |
| SSRCH/2122 | 1 NO SPSTbetween 3 NC SPST |
| SSRCH/2211 | 2 NC SPST and 2 NO SPST, grouped |
| SSRCH/2212 | 1 NO SPSTbetween 3 NC SPST |
| SSRCH/2221 | 3 NC SPST, grouped and 1 NO SPST |
Dual Switch Pair: Four (4) SPST contacts (two pairs), configured with a single, internally spliced common per pair, see Figure 2.2.2.2-C and Figure 2.2.2.2-D.
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| Configuration (SSRCH/AB/CD) | Common A | Common B |
| SSRCH/11/11 | 2 NO SPST | 2 NO SPST |
| SSRCH/11/22 | 2 NO SPST | 2 NC SPST |
| SSRCH/12/12 | 1 NO, 1 NC SPST | 1 NO, 1 NC SPST |
| SSRCH/22/22 | 2 NC SPST | 2 NC SPST |
| SSRCH/21/21 | 1 NC SPST and 1 NO SPST | 1 NC SPST and 1 NO SPST |
| SSRCH/11/12 | 2 NO SPST | 1 NO SPST and 1 NC SPST |
| SSRCH/11/21 | 2 NO SPST | 1 NC SPST and 1 NO SPST |
| SSRCH/12/11 | 1 NO SPST and 1 NC SPST | 2 NO SPST |
| SSRCH/12/21 | 1 NO SPST and 1 NC SPST | 1 NO SPST and 1 NC SPST |
| SSRCH/12/22 | 1 NO SPST and 1 NC SPST | 2 NC SPST |
| SSRCH/21/11 | 1 NC SPST and 1 NO SPST | 2 NO SPST |
| SSRCH/21/12 | 1 NC SPST and 1 NO SPST | 1 NO SPST and 1 NC SPST |
| SSRCH/21/22 | 1 NC SPST and 1 NO SPST | 2 NC SPST |
| SSRCH/22/11 | 2 NC SPST | 2 NO SPST |
| SSRCH/22/12 | 2 NC SPST | 1 NO SPST and 1 NC SPST |
| SSRCH/22/21 | 2 NC SPST | 1 NC SPST and 1 NO SPST |
Three Switch, Single Common, One Switch Single Common: Three (3) SPST contacts configured with a single, internally spliced common and one (1) SPST contact, configured with a single, internally spliced common, see Figure 2.2.2.2-E and Figure 2.2.2.2-F.
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| Configuration (SSRCH/ABC/D) | Common A | Common B |
| SSRCH/111/2 | 3 NO SPST | 1 NC SPST |
| SSRCH/222/1 | 3 NC SPST | 1 NO SPST |
| SSRCH/111/1 | 3 NO SPST | 1 NO SPST |
| SSRCH/112/1 | 2 NO SPST, grouped and 1 NC SPST | 1 NO SPST |
| SSRCH/112/2 | 2 NO SPST, grouped and 1 NC SPST | 1 NC SPST |
| SSRCH/121/1 | 2 NO SPST, split and 1 NC SPST | 1 NO SPST |
| SSRCH/121/2 | 2 NO SPST, split and 1 NC SPST | 1 NC SPST |
| SSRCH/122/1 | 1 NO SPST and 2 NC SPST, grouped | 1 NO SPST |
| SSRCH/122/2 | 1 NO SPST and 2 NC SPST, grouped | 1 NC SPST |
| SSRCH/211/1 | 1 NC SPST and 2 NO SPST, grouped | 1 NO SPST |
| SSRCH/211/2 | 1 NC SPST and 2 NO SPST, grouped | 1 NC SPST |
| SSRCH/212/1 | 2 NC SPST, split and 1 NC SPST | 1 NO SPST |
| SSRCH/212/2 | 2 NC SPST, split and 1 NC SPST | 1 NC SPST |
| SSRCH/221/1 | 2 NC SPST, grouped and 1 NO SPST | 1 NO SPST |
| SSRCH/221/2 | 2 NC SPST, grouped and 1 NO SPST | 1 NC SPST |
| SSRCH/222/2 | 3 NC SPST | 1 NC SPST |
Signal Description
For a description of the input and output functions of the Combination SSR (SSRCH) component, see Figure 2.2.2.2-G.
| Signals |
Pins | Logic Functions Normally Open (1)* | Logic Functions Normally Closed (2)** |
| A, B, C, and D | 1 (A), 3 (B), 8 (C), 6 (D) |
Shorted to Common A or B when the inputs (IN) are Active | Shorted to Common A or B when the inputs (IN) are not Active |
| Common | 2 (COM A) 7 (COM B) |
Signal Common A and B | |
| IN | 4 & 5 | Active when +28 VDC is applied across the inputs (IN) | |
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Notes
* 1 = Normally Open (NO) SSR ** 2 = Normally Closed (NC) SSR |
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2.2.2.3
| Description | Parameters (SSR1 and SSR2) | SSR3H | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| +28 VDC Input | +14 VDC Input | +5 VDC Input | +28 VDC Input | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Input/Output Parameters | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Maximum Voltage On | +32 VDC | +18 VDC | +6 VDC | +32 VDC | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Nominal Voltage On | +28 VDC | +14 VDC | +5VDC | +28 VDC | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Minimum Voltage On | +18 VDC | +8 VDC | +4 VDC | +8 VDC | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Voltage Off (Maximum) | +6 VDC | +4 VDC | +2 VDC | +1.5 VDC | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Typical Operation Current | 6.3 mA (SSR1 /SSR2) 25 mA (SSRCH) |
6.2 mA | 12.1 mA | 10 mA | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Typical Input Impedance at 25°C | 4,444 ohms (SSR1 / SSR2) 1,111 ohms (SSRCH) |
2,258 ohms | 413 ohms | 2800 ohms | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Turn On Time Maximum at 25°C | 3 ms | 3 ms | 5 ms | 0.15 ms | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Turn Off Time Maximum at 25°C | 0.5 ms | 0.5 ms | 0.5 ms | 0.4 ms | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Maximum Output Voltage | +32 VDC or 28 VAC (VRMS) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Minimum Output Voltage | N/A | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Output Parameters | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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For Qualification Summary, see Appendix A