Datasheet

Full
Range
Step
VREF_val_tol
VREF
(VDDQ DC)
VREF
Voltage
Time
t1
VREFmin
VREFmax
Figure 50. VREF full step from VREFmin to VREFmax case
Full
Range
Step
VREF_val_tol
VREF
(VDDQ DC)
VREF
Voltage
Time
t1
VREFmin
VREFmax
Figure 51. VREF full step from VREFmax to VREFmin case
Table 26. DQ Internal VREF Specifications
Symbol
Parameter
Min.
Typ.
Max.
Unit
Note
VREF_max_R1
V
REF
max operating point range1
92%
-
-
V
DDQ
1,10
VREF_min_R1
V
REF
min operating point range1
-
-
60%
V
DDQ
1,10
VREF_max_R2
V
REF
max operating point range2
77%
-
-
V
DDQ
1,10
VREF_min_R2
V
REF
min operating point range2
-
-
45%
V
DDQ
1,10
VREF step
V
REF
Stepsize
0.50%
0.65%
0.80%
V
DDQ
2
VREF_set_tol
V
REF
Set Tolerance
-1.625%
0.00%
1.625%
V
DDQ
3,4,6
-0.15%
0.00%
0.15%
V
DDQ
3,5,7
VREF_time
V
REF
Step Time
-
-
150
ns
8,11
VREF_val_tol
V
REF
Valid tolerance
-0.15%
0.00%
0.15%
V
DDQ
9
Note 1. V
REF
DC voltage referenced to V
DDQ_DC
. V
DDQ_DC
is 1.2V.
Note 2. V
REF
stepsize increment/decrement range. V
REF
at DC level.
Note 3. V
REF_new
= V
REF_old
+ n x V
REF_step
; n = number of step; if increment use “+”; If decrement use “-”.
Note 4. The minimum value of V
REF
setting tolerance = V
REF_new
- 1.625% x V
DDQ
. The maximum value of V
REF
setting tolerance = V
REF_new
+ 1.625% x V
DDQ
for n>4.
Note 5. The minimum value of V
REF
setting tolerance = V
REF_new
- 0.15% x V
DDQ
. The maximum value of V
REF
setting tolerance = V
REF_new
+ 0.15% x V
DDQ
for n>4.
Note 6. Measured by recording the min and max values of the V
REF
output over the range, drawing a straight line between those points
and comparing all other V
REF
output settings to that line.
Note 7. Measured by recording the min and max values of the V
REF
output across 4 consecutive steps (n = 4), drawing a straight line
between those points and comparing all other V
REF
output settings to that line.
Note 8. Time from MRS command to increment or decrement one step size up to full range of V
REF
.
Note 9. Only applicable for DRAM component level test/characterization purpose. Not applicable for normal mode of operation. V
REF
valid
is to qualify the step times which will be characterized at the component level.
Note 10. DRAM range1 or 2 set by MRS bit MR6, A6.
Note 11. If the V
REF
monitor is enabled, V
REF_time
must be derated by: +10ns if DQ load is 0pF and an additional +15ns/pF of DQ loading.
AS4C256M16D4
Confidential
- 64 of 201 -
Rev.1.0 Aug.2019