11-13
CHUNG-YU WU
Conventional Weighted-Current-Source D/A Converter
YU-CHUNG |
13-11 |
WU |
|
11-15
CHUNG-YU WU
Two-Stage Weighted Current Array D/A Converter
YU-CHUNG |
15-11 |
WU |
|
11-16
CHUNG-YU WU
I1 = K (W/L)(Va-Vth1)2
IN = K (W/L)(Va-VthN)2
(VthN-Vth1) may be as large as 80 mV due to the oxide thinning effect.
Conventional switched current source.
YU-CHUNG |
16-11 |
WU |
|
11-18
CHUNG-YU WU
Spice Monte-Carlo simulation results for (a) Conventional weighted current sources; (b) current sources with threshold-voltage compensation.
11-20
CHUNG-YU WU
CKs
Din |
D |
VB1
DB
VB1
Vdd
out
out |
in VB1 |
in |
|
VB1 |
|
Vss
(a)
(b)
(a) The circuit; (b) The SPICE simulated output waveforms of the input driver with high logic-threshold.
11-21
CHUNG-YU WU
16I |
8I |
4I |
2I |
I |
I |
Symmetrical layout configuration of each 5-bit current array.
Compact |
Symmetry |
||
|
|
|
|
|
M2 |
|
M2 |
M2 M2
Mc
M2 Mc
M2 |
M2 |
Different layout arrangement for the devices M2 and Mc in each current source: (a) 4-cell unit; (b) 5-cell unit.
11-22
CHUNG-YU WU
Differential linearity error of the D/A converter
Integral linearity error of the D/A converter.