SLUS634F November 2004 – January 2022 TPS2384
PRODUCTION DATA
The TPS2384 uses a four-point measurment technique using two low level probe signals (typically 4.4 V and 8.8 V) during the discovery process to determine whether a valid PD is present. The use of a multipoint detection method for the PD resistor measurement allows accurate detection even when series steering diodes are present. The low level probe voltages also prevent damage to non-802.3 devices. When a valid PD has been detected the TPS2384 moves to classification. If a valid PD has not been detected the TPS2384 continues to cycle through the discovery process. The waveform in Figure 8-4 shows typical N-pin waveforms for the discovery of a valid PD and the failure to discovery due to a discovery resistor of 15 kΩ and 33 kΩ.