Rev. 0.8 / Oct. 2007

13

3.2.4 Differential Input AC logic Level

3.2.5 Differential AC output parameters

Symbol

Parameter

Min.

Max.

Units

Notes

ac differential input voltage

0.5

VDDQ + 0.6

V

1

ac differential cross point voltage

0.5 * VDDQ - 0.175

0.5 * VDDQ + 0.175

V

2

1. VIN(DC) specifies the allowable DC execution of each input of differential pair such as CK, CK, DQS, DQS,

LDQS, LDQS, UDQS and UDQS.

2. VID(DC) specifies the input differential voltage |VTR -VCP | required for switching, where VTR is the true input

(such as CK, DQS, LDQS or UDQS) level and VCP is the complementary input (such as CK, DQS, LDQS

or UDQS) level. The minimum value is equal to VIH(DC) - V IL(DC).

Note:

1. VID(AC) specifies the input differential voltage |VTR -VCP | required for switching, where VTR is the true input

signal (such as CK, DQS, LDQS or UDQS) and VCP is the complementary input signal (such as CK, DQS, LDQS

or UDQS). The minimum value is equal to V IH(AC) - V IL(AC).

2. The typical value of VIX(AC) is expected to be about 0.5 * VDDQ of the transmitting device and VIX(AC) is

expected to track variations in VDDQ . VIX(AC) indicates the voltage at which differential input signals must

cross.

Symbol

Parameter

Min.

Max.

Units Notes

ac differential cross point voltage

0.5 * VDDQ - 0.125 0.5 * VDDQ + 0.125

V

1

Note:

1. The typical value of VOX(AC) is expected to be about 0.5 * V DDQ of the transmitting device and VOX(AC) is

expected to track variations in VDDQ . VOX(AC) indicates the voltage at whitch differential output signals

must cross.

Crossing point

< Differential signal levels >