TLC7528C, TLC7528E, TLC7528I
DUAL 8-BIT MULTIPLYING
DIGITAL-TO-ANALOG CONVERTERS
SLAS062B – JANUARY 1987 – REVISED MARCH 2000
APPLICATION INFORMATION
C3
47 pF
R5
4
2
REFA
OUTA
–
V
I
DACA
(R )
S
17
30 kΩ
V
DD
3
1
A1
+
RFBA
AGND
R4
8
14–7
Data In
DB0–DB7
30 kΩ
TLC7528
DACB
R3
–
15
16
5
High Pass
Out
CS
20
19
OUTB
A2
10 kΩ
+
WR
(R )
F
RFBB
REFB
DGND
18
6
DACA/DACB
Bandpass Out
DACA1 AND DACB1
C1
1000 pF
–
2
REFA
OUTA
4
DACA
(R )
1
17
A3
+
V
3
1
DD
C2
RFBA
AGND
8
14–7
Data In
DB0–DB7
TLC7528
DACB
1000 pF
–
15
16
5
CS
20
19
OUTB
WR
(R )
2
Low Pass Out
A4
+
RFBB
REFB
DGND
18
6
DACA/DACB
DACA2 and DACB2
Circuit Equations:
C
= C , R = R , R = R
1
2
1
2
4
5
R
R
R
3
4
F
Q
·
R
fb(DACB1)
Where:
R
is the internal resistor connected between OUTB and RFBB
fb
R
F
G
–
R
S
NOTES: A. Op-amps A1, A2, A3, and A4 are TL287.
B. CS compensates for the op-amp gain-bandwidth limitations.
256 (DAC ladder resistance)
C. DAC equivalent resistance equals
DAC digital code
Figure 10. Digitally Controlled State-Variable Filter
13
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TI [ TEXAS INSTRUMENTS ]
