Comparators are very sensitive to input noise. For best results, adhere to the following layout guidelines.
- Use a printed-circuit-board (PCB) with a good, unbroken, low-inductance ground plane. Proper grounding (use of a ground plane) helps maintain specified device performance and input/output trace impedances.
- To minimize supply noise, place a decoupling capacitor (0.1-μF ceramic, surface-mount capacitor) directly between VCCI/VCCO and VEE.
- On the inputs and outputs, utilize matched trace lengths to minimize timing skew. Also, minimize trace lengths and maximize ground pour spacings around the input and output traces to limit parasitic capacitance.
- Solder the device directly to the PCB rather than using a socket.
- For slow-moving input signals, take care to prevent parasitic feedback. A small capacitor (1000pF or less) placed between the inputs can help eliminate oscillations in the transition region. This capacitor causes minimal degradation to propagation delay when source impedance is low.
- Use a 100Ω termination resistor across the
device's LVDS outputs.
- Use higher performance substrate materials such as Rogers or High-Speed FR4.
- PCB signal layers from the TLV3604EVM are shown for reference.