HS400 reference load

The circuit in Figure 14 shows the reference load used to define the HS400 Device Output Timings and overshoot

/ undershoot parameters.

The reference load is made up by the transmission line and the CREFERENCE capacitance.

The reference load is not intended to be a precise representation of the typical system environment nor a

depiction of the actual load presented by a production tester.

System designers should use IBIS or other simulation tools to correlate the reference load to system

environment. Manufacturers should correlate to their production test conditions.

Delay time (td) of the transmission line has been introduced to make the reference load independent from

the PCB technology and trace length.

Figure 14: HS400 reference load

8.3 Bus Signal Levels

As the bus can be supplied with a variable supply voltage, all signal levels are related to the supply voltage.

Figure 15: Bus Signal Levels

Open-drain Mode Bus Signal Level

Table 21: Open-drain Bus Signal Level

Parameter

Symbol

Min.

Max.

Unit

Conditions

Output HIGH voltage

VOH

VDD – 0.2

V

IOH = -100 μA

Output LOW voltage

VOL

0.3

V

IOL = 2 mA

The input levels are identical with the push-pull mode bus signal levels.

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