HA-2420, HA-2425
Test Circuits and Waveforms (Continued)
+5V
EN
HI-508A
MUX
SINE WAVE
INPUT
IN2
IN1
IN3
IN4
IN5
IN6
IN7
IN8
A2
HA-2420/2425
-IN
V
O
OUT
GND
+IN
OUT
S/H
HOLD
HOLD
S/H
CONTROL CAP
CONTROL
SAMPLE
C
V
H
INP-P
OUTPUT
A0
A1
∆V
S/H CONTROL INPUT
∆t
NOTE: Compute hold mode feedthrough attenuation from the formula:
HOLD
V
OUT
----------------------------------
Feedthrough Attenuation = 20log
V
HOLD
IN
NOTE: Measure the slope of the output during hold, ∆V/∆t,
and compute drift current from: I = C ∆V/∆t.
Where V
OUT
sinewave during the hold mode.
HOLD = Peak-to-Peak value of output
D
H
FIGURE 3. DRIFT CURRENT TEST
FIGURE 4. HOLD MODE FEEDTHROUGH ATTENUATION
Schematic Diagram
OFFSET ADJ.
V+
R
R
Q
Q
1
2
64
Q
89
J
63
Q
Q
58
Q
Q
Q
29
30
65
Q
Q
17
23
Q
5
Q
Q
106
90
Q
66
Q
2
Q
72
Q
4
82
59
Q
Q
Q
R
74
45
46
J
R
61
Q
P
73
Q
Q
7
9
Q
91
Q
105
Q
87
Q
51
Q
Q
52
Q
15
Q
Q
6
C
7
Q
H
47
Q
Q
Q
48
11
Q
53
Q
54
49
Q
50
27
D
1
Q
75
Q
19
Q
20
21
Q
8
Q
31
C
3
Q
R
32
15pF
9
Q
Q
100
R
8
OUT
Q
101
Q
Q
3
24
Q
Q
33 34
Q
R
18
10
56
Q
25
Q
10
Q
Q
38
13
Q
77
S/H
Q
Q
35
76
CONTROL
Q
Q
55
22
Q
C
26
4
Q
Q
83
Q
69
67
GND
J
60
Q
68
R
121
Q
12
Q
14
GND
Q
78
J
86
R
11
Q
83
Q
Q
Q
39
40
Q
Q
79
70
J
Q
57
41
Q
103
Q
42
43
Q
102
Q
44
Q
Q
71
Q
80
62
Q
16
R
14
R
13
Q
81
-IN
+IN
V-
5-4
INTERSIL [ Intersil ]
