SGS Thomson Microelectronics TDA7317 Datasheet
TDA7317
FIVEBANDSDIGITALCONTROLLEDGRAPHICEQUALIZER
VOLUMECONTROLIN 0.375dBSTEP
FIVE BANDS STEREO GRAPHIC EQUAL-
IZER
CENTER FREQUENCY, BANDWIDTH, MAX
BOOST/CUT DEFINED BY EXTERNAL COMPONENTS
±14dB CUT/BOOSTCONTROL IN2dB/STEP
ALL FUNCTIONS PROGRAMMABLE VIA SE-
RIALBUS
VERYLOW DISTORTION
VERY LOW NOISE AND DC STEPPING BY
USE OF A MIXED BIPOLAR/CMOS TECHNOLOGY
ORDERING NUMBER: TDA7317
SDIP30
DESCRIPTION
The TDA7317 is a monolithic, digitally controlled
graphicequali zerrealizedin BiCM OS mixedtechnology. The ster eosignal,beforeany filtering,can be at-
BLOCK DIAGRAM
tenuated up to -17.625dB in 0.375dB step.
All the functions can be programmed via serial
bus making easy to build a µPcontrolledsystem.
Signalpath is designedfor verylownoiseanddistortion.
November 1999
1/12
TDA7317
PIN CONNECTION
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
T
op
T
stg
R
tjvins
ELECTRICAL CHARACTERISTICS (T
Supply Voltage 10.2 V
S
Operating Temperature Range -40 to +85 °C
Storage Temperature Range -55 to +150 °C
Thermal Resistance Junction pins max 85
=25°C, VS= 9V, RL= 10KΩ,Rg= 600Ω, f = 1KHz VIN=
amb
1Vrms, all controlsin flat position (AV = 0dB) unlessotherwise specified).
Symbol Parameter Test Condition Min. Typ. Max. Unit
SUPPLY
V
S
I
S
SVR Ripple Rejection f = 300Hz to 10KHz 60 80 dB
Supply Voltage 6 9 10 V
Supply Current 8 14 20 mA
C/W
°
2/12
TDA7317
ELECTRICALCHARACTERISTICS(continued)
Symbol Parameter Test Condition Min. Typ. Max. Unit
INPUT
V
R
I
IN max
I
NS
Input Resistance 20 30 40 KΩ
Max Input Signal THD = 0.3% 2 2.5 V
Input Separation (1) 80 100 dB
VOLUMECONTROL
C
RANGE
A
A
A
V
VMIN
VMAX
STEP
E
A
E
T
DC
Control Range 17.625 dB
Min. Attenuation -0.5 0 0.5 dB
Max. Attenuation 16.7 17.625 18.6 dB
Step Resolution 0.175 0.375 0.575 dB
Attenuation Set Error -1 1 dB
Tracking Error 0.5 dB
DC Steps adjacent attenuation steps 0 3 mV
GRAPHIC EQUALIZER
THD Distortion 0.01 0.1 %
C
s
e
NO
Channel Separation 80 100 dB
Output Noise BW = 20Hz to 20KHz
820µV
flat, AV = 0dB
A curve 6
BW = 20Hz to 20KHzAV =0dB
S/N Signal to Noise Ratio A
B
C
RANGE
step
Step Resolution 1 2 3 dB
Control Range max boost/cut ±12 ±14 ±16 dB
All bands = max. boost
All bands = max. cut
= 0dB; V
V
ref
=1V
RMS
24
6
100 dB
VDC DC Steps Adiacent Control Steps 0.5 3 mV
AUDIO OUTPUTS
RMS
V
µ
µV
V
µ
V
O
R
L
C
L
R
O
V
OUT
Output Voltage THD = 0.3% 2 2.5 V
Output Load Resistance 2 KΩ
Output Load Capacitance 10 nF
Output Resistance 5 10 20
DC Voltage Level 4.2 4.5 4.8 V
BUS INPUTS
V
IL
V
IH
I
IN
V
O
Input Low Voltage 1V
Input High Voltage 3 V
Input Current -5 +5
Output Voltage SDA
IO= 1.6mA 0.4 V
Acknowledge
ADDRESSPIN (Internal 50KΩ pull down resistor)
V
IL
V
IH
NOTE: The input is grounded thru the 2.2µP capacitors
Input Low Voltage 1V
Input High Voltage VCC-1V V
RMS
Ω
A
µ
3/12
TDA7317
DEVICEDESCRIPTION
The TDA7317 is a five bands, digitally controlled
stereo Graphic Equalizer.
The device is intended for high quality audio application in Hi-Fi, TV and car radio systems where
feature like low noise and THD are key factors. A
mixed Bipolar Cmos Technologyallows:
Cmos analog switches for pop free commutations, high frequency op.amp. (GWB = 10MHz)
and high linearity polisilicon resistor for THD =
0.01 (at Vin = 1Vrms) and a S/N ratio of 102dB.
The internal Block Diagramis shownon page1.
The first stage is a volume control. The control
range is 0 to -17.625dBwith 0.375dBstep.
The very high resolution (0.375dB step) allows
the implementation of closed loop amplitude control system completely free from any acustical effect (steppingvariation and pumping effect).
The volume control is followed by a serial five
bands equalizer. Each filtering cell is the biquad
cell shown in fig. 1
The internal resistor string is fixing the boost/cut
value while the buffer makes the Q (quality factor)
and central frequency, set by external components, fully indipendentfrom the internalresistors.
Each filtering cell is realized using only 4 external
components (2 capacitorsand 2 resistors)allowing a flexible selection of centre frequency fo, Q
factor and gain. Here below the basic formulae
and the key features of each band pass filter are
reported:
= center frequency
f
o
Gv = gain/lossat the centerfrequencyf
Gv = 20log(Av)
o
f
o
=
Q
f2− f
1
wheref2,f1= 3dB Bandwidth limits.
(R2⋅C2)+(R2⋅C1)
=
A
v
(R2 ⋅ C1 )+(R2 ⋅ C2 )
√(R1
=
Q
(R2 ⋅C1 )+(R2 ⋅ C2 )
=
f
o
2π ⋅√(R1 ⋅ R2 ⋅
+ (R1⋅
⋅ C1 ⋅ R2 ⋅ C2 )
1
C1⋅ C2)
C1
)
If C1 is fixed, then:
2
Q
R2 =
C2
π⋅C1⋅
2
R1
=
A
− 1− Q
v
f
(A
v
=
Av− 1 −Q
− 1)
o
1
(A
⋅
A
(
2
⋅ C1
2
−1 ) ⋅ Q
v
− 1 −Q2)
v
⋅
R2
2
Likewise, the components’values can be determinedby fixing oneof theother three parameters.
Referring to fig. 1 the suggested R2 value should
be higher than 2KΩin order to have a good THD
(internalop. amp. current limit).
Viceversa the R1 value should be equal or lower
than 51KΩ in order to keep the ”click”(DC step)
very low.
A typical applicationis shownby fig. 2
Fig. 1
4/12
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