Datasheet

AC and DC output Measurement levels
Output Driver DC Electrical Characteristics
The DDR4 driver supports two different R
ON
values. These R
ON
values are referred as strong(low R
ON
) and
weak mode(high R
ON
). A functional representation of the output buffer is shown in the figure below. Output
driver impedance R
ON
is defined as follows:
The individual pull-up and pull-down resistors (R
ONPu
and R
ONPd
) are defined as follows:
R
ONPu
=
V
DDQ
- Vout
| I out |
under the condition that RONPd is off
R
ONPd
=
Vout
| I out |
under the condition that RONPu is off
To other
circuitry like
VSSQ
Chip In Drive Mode
R
ONPu
I
Pu
DQ
VDDQ
Output Drive
I
Pd
R
ONPd
I
out
V
out
Figure 179. Output driver
AS4C256M16D4
Confidential
- 186 of 201 -
Rev.1.0 Aug.2019