TLC7528C_15 Datasheet, PDF (13/28 Pages) Texas Instruments – DUAL 8-BIT MULTIPLYING DIGITAL-TO-ANALOG CONVERTERS

TLC7528C, TLC7528E, TLC7528I
DUAL 8ĆBIT MULTIPLYING
DIGITALĆTOĆANALOG CONVERTERS
SLAS062E − JANUARY 1987 − REVISED NOVEMBER 2008
APPLICATION INFORMATION
C3
VI
8
Data In
4 _REFA
17
VDD
DACA
(RS)
15
CS
16
WR
5
DGND
TLC7528
DACB
(RF)
6
DACA / DACB
OUTA ²
3
RFBA
AGND ¹
OUTB ²⁰
19
RFBB
REFB ¹⁸
DACA1 AND DACB1
A1
C1
R3
10 kΩ
47 pF
R5
30 kΩ
R4
30 kΩ
A2
High Pass
Out
Bandpass Out
8
Data In
4 REFA
17 _VDD
DACA
(R1)
15 _CS
16 _WR
5 _DGND
TLC7528
DACB
(R2)
6 _{DACA / DACB}
OUTA ²
3
RFBA
AGND ¹
OUTB ²⁰
19
RFBB
REFB ¹⁸
DACA2 and DACB2
1000 pF
A3
C2
1000 pF
A4
Circuit Equations:
C1 = C2, R1 = R2, R4 = R5
Q=
R3
R4
RF
Rfb(DACB1)
Where:
Rfb is the internal resistor connected between OUTB and RFBB
G
−
RF
RS
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
Low Pass Out
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