| Characteristic | Single-Ended Input | Differential Input |
|---|---|---|
| Number of Signal Lines | 1 signal line + common ground | 2 signal lines (AIN+ and AIN-) |
| Reference | System GND as reference | Voltage difference between signal lines |
| Typical Circuit | Signal→ADC→GND | Signal+→ADC+, Signal-→ADC- |
| Characteristic | Single-Ended Input | Differential Input |
|---|---|---|
| Common-Mode Rejection | No rejection capability | Rejects common-mode noise (CMRR>60dB) |
| Ground Loop Impact | Severely affected by ground potential differences | Tolerates ±10V ground potential differences |
| EMI Sensitivity | High (requires shielded cables) | Low (twisted pair sufficient) |
| Characteristic | Single-Ended Input | Differential Input |
|---|---|---|
| Effective Signal Amplitude | Actual signal voltage value | Voltage difference between signal lines |
| Small Signal Measurement | Not suitable (<10mV, prone to interference) | Suitable (can measure μV-level signals) |
| Long-Distance Transmission | ≤10 meters (severe signal attenuation) | ≥100 meters (maintains accuracy) |
| Characteristic | Single-Ended Input | Differential Input |
|---|---|---|
| Circuit Complexity | Simple (saves 1 wire) | More complex (requires differential amplifier) |
| ADC Requirements | Standard single-ended ADC | True differential input ADC |
| Cost | Low (saves 30% wiring cost) | High (component cost increases by 50%+) |
| Scenario | Single-Ended Input Applications | Differential Input Applications |
|---|---|---|
| Industrial Control | Cabinet-mounted sensors (temperature/humidity) | Remote motor current monitoring |
| Consumer Electronics | Mobile phone battery voltage detection | Professional audio equipment XLR input |
| Medical Devices | Non-critical parameter monitoring | ECG/EEG bioelectric signal acquisition |
| Test & Measurement | Low-speed data acquisition (<1kHz) | Vibration/strain precision measurement |
| Issue Type | Single-Ended Input Performance | Differential Input Performance |
|---|---|---|
| Ground Wire Break | Complete signal failure | Continues working (detects difference) |
| EMI Interference | Significant signal fluctuation | Remains stable (noise canceled) |
| Power Supply Noise | Directly superimposed on signal | Rejected by common-mode suppression |
graph TD A[Signal transmission distance>10m?] -->|Yes| B[Must choose differential] A -->|No| C{Signal amplitude<10mV?} C -->|Yes| B C -->|No| D{Strong electromagnetic interference?} D -->|Yes| B D -->|No| E[Single-ended more economical]
Prefer differential input when:
Transmission distance >10 meters
Signal <10mV
High-interference environments (industrial/medical)
Consider single-ended input when:
Short-distance (<1m) board-level signals
Cost-sensitive consumer electronics
Simple applications with signal amplitude >100mV
Key fundamental difference:
Single-ended: Absolute measurement of "signal vs ground"
Differential: Relative measurement of "signal vs signal"
Note: Modern high-precision systems (e.g., 24-bit ADC acquisition) use differential conversion technology internally even with single-ended physical interfaces to enhance performance.
