Datasheet
Table 78. Capacitance
Symbol
Parameter
DDR4-2400/2666
Unit
Note
Min.
Max.
C
IO
Input/output capacitance
0.55
1.15
pF
1,2,3
C
DIO
Input/output capacitance delta
-0.1
0.1
pF
1,2,3,11
C
DDQS
Input/output capacitance delta DQS and DQS#
-
0.05
pF
1,2,3,5
C
CK
Input capacitance, CK and CK#
0.2
0.7
pF
1,3
C
DCK
Input capacitance delta CK and CK#
-
0.05
pF
1,3,4
C
I
Input capacitance(CTRL, ADD, CMD pins only)
0.2
0.7
pF
1,3,6
C
DI_CTRL
Input capacitance delta (All CTRL pins only)
-0.1
0.1
pF
1,3,7,8
C
DI_ADD_CMD
Input capacitance delta (All ADD/CMD pins only)
-0.1
0.1
pF
1,2,9,10
C
ALERT
Input/output capacitance of ALERT
0.5
1.5
pF
1,3
C
ZQ
Input/output capacitance of ZQ
-
2.3
pF
1,3,12
C
TEN
Input capacitance of TEN
0.2
2.3
pF
1,3,13
Note 1. This parameter is not subject to production test. It is verified by design and characterization. The silicon only capacitance is
validated by deem bedding the package L and C parasitic. The capacitance is measured with V
DD
, V
DDQ
, V
SS
, V
SSQ
applied with all
other signal pins floating. Measurement procedure TBD. Used to define a differential signal slew-rate.
Note 2. DQ, DM#, DQS, DQS#. Although the DM pins have different functions, the loading matches DQ and DQS.
Note 3. This parameter applies to monolithic devices only; stacked/dual-die devices are not covered here.
Note 4. Absolute value CK-CK#.
Note 5. Absolute value of C
IO
(DQS) - C
IO
(DQS#).
Note 6. C
I
applies to ODT, CS#, CKE, A0-A16, BA0-BA1, BG0, RAS#/A16, CAS#/A15, WE#/A14, ACT# and PAR.
Note 7. C
DI_CTRL
applies to ODT, CS# and CKE.
Note 8. C
DI_CTRL
= C
I
(CTRL) - 0.5 x ( C
I
(CLK) + C
I
(CLK#)).
Note 9. C
DI_ADD_CMD
applies to, A0-A16, BA0-BA1, BG0, RAS#/A16, CAS#/A15, WE#/A14, ACT# and PAR.
Note 10. C
DI_ADD_CMD
= C
I
(ADD_CMD) - 0.5 x ( C
I
(CLK) + C
I
(CLK#)).
Note 11. C
DIO
= C
IO
(DQ,DM) - 0.5 x (C
IO
(DQS) + C
IO
(DQS#)).
Note 12. Maximum external load capacitance on ZQ pin: TBD pF.
Note 13. TEN pin may be DRAM internally pulled low through a weak pull-down resistor to V
SS
. In this case C
TEN
might not be valid and
system shall verify TEN signal with vendor specific information.
AS4C256M16D4
Confidential
- 162 of 201 -
Rev.1.0 Aug.2019