Datasheet

AD7528
REV. B–8–
C681e–0–9/98
PRINTED IN U.S.A.
DIGITALLY CONTROLLED DUAL TELEPHONE
ATTENUATOR
In this configuration the AD7528 functions as a 2-channel digi-
tally controlled attenuator. Ideal for stereo audio and telephone
signal level control applications. Table IV gives input codes vs.
attenuation for a 0 dB to 15.5 dB range.
Input Code = 256 ⫻ 10 exp
−






Attenuation dB,
20
V
IN
B
V
OUT
A
V
IN
A
DATA BUS
DAC A/DAC B
CS
WR
AD7528
DB0
DB7
DAC A
DAC B
V
DD
V
OUT
B
A1
A2
SUGGESTED
OP AMP: AD644
Figure 15. Digitally Controlled Dual Telephone Attenuator
Table IV. Attenuation vs. DAC A, DAC B Code for the Circuit
of Figure 15
Attn. DAC Input Code In Attn. DAC Input Code In
dB Code Decimal dB Code Decimal
0.0 1 1 1 1 1 1 1 1 255 88.0 0 1 1 0 0 1 1 0 102
0.5 1 1 1 1 0 0 1 0 242 88.5 0 1 1 0 0 0 0 0 96
1.0 1 1 1 0 0 1 0 0 228 89.0 0 1 0 1 1 0 1 1 91
1.5 1 1 0 1 0 1 1 1 215 89.5 0 1 0 1 0 1 1 0 86
2.0 1 1 0 0 1 0 1 1 203 10.0 0 1 0 1 0 0 0 1 81
2.5 1 1 0 0 0 0 0 0 192 10.5 0 1 0 0 1 1 0 0 76
3.0 1 0 1 1 0 1 0 1 181 11.0 0 1 0 0 1 0 0 0 72
3.5 1 0 1 0 1 0 1 1 171 11.5 0 1 0 0 0 1 0 0 68
4.0 1 0 1 0 0 0 1 0 162 12.0 0 1 0 0 0 0 0 0 64
4.5 1 0 0 1 1 0 0 0 152 12.5 0 0 1 1 1 1 0 1 61
5.0 1 0 0 1 0 0 0 0 144 13.0 0 0 1 1 1 0 0 1 57
5.5 1 0 0 0 1 0 0 0 136 13.5 0 0 1 1 0 1 1 0 54
6.0 1 0 0 0 0 0 0 0 128 14.0 0 0 1 1 0 0 1 1 51
6.5 0 1 1 1 1 0 0 1 121 14.5 0 0 1 1 0 0 0 0 48
7.0 0 1 1 1 0 0 1 0 114 15.0 0 0 1 0 1 1 1 0 46
7.5 0 1 1 0 1 1 0 0 108 15.5 0 0 1 0 1 0 1 1 43
For further applications information the reader is referred to
Analog Devices Application Note on the AD7528.
20-Lead Cerdip (Q-20)
0.97 (24.64)
0.935 (23.75)
SEATING
PLANE
0.02 (0.5)
0.016 (0.41)
0.07 (1.78)
0.05 (1.27)
0.15 (3.8)
0.125 (3.18)
0.20 (5.0)
0.14 (3.56)
0.11 (2.79)
0.09 (2.28)
20
110
11
0.28 (7.11)
0.24 (6.1)
PIN 1
0.14 (3.56)
0.125 (3.17)
158
08
0.32 (8.128)
0.29 (7.366)
0.011 (0.28)
0.009 (0.23)
LEAD NO. 1 IDENTIFIED BY DOT OR NOTCH
LEADS ARE SOLDER OR TIN-PLATED KOVAR OR ALLOY 42
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
20-Lead Plastic DIP (N-20)
SEATING
PLANE
0.021 (0.533)
0.015 (0.381)
0.065 (1.66)
0.045 (1.15)
0.11 (2.79)
0.09 (2.28)
0.145 (3.683)
MIN
0.125 (3.175)
MIN
20
110
11
PIN 1
1.07 (27.18) MAX
0.255 (6.477)
0.245 (6.223)
0.32 (8.128)
0.30 (7.62)
0.011 (0.28)
0.009 (0.23)
0.135 (3.429)
0.125 (3.17)
158
08
LEAD NO. 1 IDENTIFIED BY DOT OR NOTCH
LEADS ARE SOLDER OR TIN-PLATED KOVAR OR ALLOY 42
20-Lead SOIC (R-20)
SEATING
PLANE
0.0118 (0.30)
0.0040 (0.10)
0.0192 (0.49)
0.0138 (0.35)
0.1043 (2.65)
0.0926 (2.35)
0.0500
(1.27)
BSC
0.0125 (0.32)
0.0091 (0.23)
0.0500 (1.27)
0.0157 (0.40)
88
08
0.0291 (0.74)
0.0098 (0.25)
3 458
11
20
10
1
0.5118 (13.00)
0.4961 (12.60)
0.4193 (10.65)
0.3937 (10.00)
0.2992 (7.60)
0.2914 (7.40)
PIN 1
20-Lead Plastic Leaded Chip Carrier (P-20A)
0.021 (0.53)
0.013 (0.33)
0.032 (0.81)
0.026 (0.66)
0.180 (4.47)
0.165 (4.19)
0.12 (3.05)
0.09 (2.29)
0.020 (0.51) MIN
0.025 (0.64)
MIN
0.060 (1.53)
MIN
3
PIN 1
IDENTIFIER
4
19
18
8
9
14
13
TOP VIEW
(PINS DOWN)
0.356 (9.04)
0.350 (8.89)
SQ
0.048 (1.21)
0.042 (1.07)
0.02
(0.51)
MAX
0.050
(1.27)
BSC
0.02 (0.51)
MAX
0.395 (10.02)
0.385 (9.78)
SQ