TDA7285
STEREO CASSETTE PLAYER AND
MOTOR SPEED CONTROLLER
WIDE OPERATING SUPPLY VOLTAGE (1.8V
to 6V)
HIGH OUTPUT POWER (30mW/32
/3V)
LOW DISTORTION DC VOLUME CONTROL
NO BOUCHEROT CELL
LOW QUIESCENT CURRENT (15mA)
NO INPUT CAPACITORS FOR PREAMPLIFI-
ERS
LOW
MOTOR
REFERENCE
VOLTAGE
(200mV)
DESCRIPTION
The TDA7285 is a monolithic integrated circuit
designed for the portable players market and as-
sembled in a plastic DIP20 and SO20. The inter-
nal functions are: preamplifier, DC volume con-
trol, headphone driver and motor speed control-
ler.
May 1997
BLOCK DIAGRAM
DIP20
SO20
ORDERING NUMBERS:
TDA7285
TDA7285D
1/11
PIN CONNECTION (Top view)
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V
S
Supply Voltage
8
V
I
Omax
Maximum Output Current
70
mA
I
m max
Maximum Motor Current
700
mA
P
tot
Total Power Dissipation T
amb
= 90
C
0.9
W
T
op
Operating Temperature
-20 to +70
C
T
stg
, T
j
Storage and Junction Temperature
-40 to 150
C
THERMAL DATA
Symbol
Description
SO20
DIP20
Unit
R
th j-amb
Thermal Resistance Junction-ambient
150
100
C/W
DC CHARACTERISTICS (T
amb
= 25
C; V
S
= 3V; R
L
= 32
(Headphone) and R
L
= 10K
(Preamplifier);
V
i
= 0; VOL. Control = V
ref
).
Terminal No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Term. Volt. (V)
0
1.5 1.5 1.5 1.5 2.7 1.4
0
2.8
0
1.6
3
3
1.4 1.5 1.5 1.5 1.5 1.5 1.5
TDA7285
2/11
ELECTRICAL CHARACTERISTICS (V
S
= 3V; R
L
= 32
, Vol. Control = 2/3 V
ref (pin 20)
; T
amb
= 25
C; f =
1KHz; unless otherwise specified
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
V
S
Supply Range
1.8
6
V
I
d
Total Quiescent Drain Current
15
22
mA
PLAYBACK AMPLIFIER
G
vo
Open Loop Gain
70
dB
G
v
Close Loop Gain
33
dB
V
O
Output Voltage
THD = 1%
600
750
mV
THD
Total Harmonic Distortion
V
O
= 330mVrms
0.05
0.25
%
I
b
Bias Current
3
A
C
t
Cross Talk
R
S
= 2.2K
; V
O
= 330mVrms
74
dB
e
n
Total Input Noise
R
S
= 2.2K
; B = 22Hz to 22KHz
1.2
V
SVR1
Ripple Rejection
R
S
= 2.2K
; Vr = 100mVrms
f = 100Hz; C
SVR
= 100
F
50
dB
HEADPHONE DRIVER
V
DC
Output DC Voltage
1.4
V
P
O
Output Power
THD = 10%
20
30
mW
P
O1
Transient Output Power
THD = 10% R
L
= 16
50
mW
G
V
Close Loop Gain
P
O
= 5mW
31
dB
Volume Control range
66
75
dB
THD
Total Harmonic Distortion
P
O
= 5mW
0.3
1
%
C
t
Cross Talk
P
O
= 5mW; R
S
= 10K
50
dB
SVR2
Ripple Rejection
R
S
= 600
; Vr = 100mV
f = 100Hz; C
SVR
= 100
F
47
dB
MOTOR SPEED CONTROL
V
ref
Motor Reference Voltage (pin 12)
0.18
0.20
0.22
V
K
Shunt Ratio
I
m
= 100mA
45
50
55
-
V
sat
Residual Voltage
I
m
= 100mA
0.13
0.30
V
V
ref
V
ref
/
V
S
Line Regulation
I
m
= 100mA;
V
S
= 1.8 to 6V
0.20
0.8
%/V
K
K
/
V
S
Voltage Characteristics of Shunt
Ratio
I
m
= 100mA;
V
S
= 1.8 to 6V
0.80
3
%/V
V
ref
V
ref
/
I
m
Load Regulation
I
m
= 30 to 200mA
0.015
0.08
%/mA
K
K
/
I
m
Current Characteristics of Shunt
Ratio
I
m
= 30 to 200mA
0.03
0.1
%/mA
V
ref
V
ref
/
T
amb
Temperature Characteristics of
Reference Voltage
I
m
= 100mA
T
amb
= -20 to +60
C
0.04
%/
C
K
K
/
T
amb
Temperature Characteristics of
Shunt Ratio
I
m
= 100mA
T
amb
= -20 to +60
C
0.02
%/
C
TDA7285
3/11
Figure 1: Test and Application Circuit
Figure 2: P.C. Board and Component Layout of the Circuit of Figure 2 (1:1 scale)
TDA7285
4/11
Figure 3: Quiescent Drain Current vs. Supply
Voltage
Figure 4: Reference voltage V
S
/2 (pin 20) vs.
Supply Voltage
Figure 5: Closed Loop Gain vs. Frequency
(PREAMPLIFIER)
Figure 6: Distortion vs. Frequency
(PREAMPLIFIER)
Figure 7: Supply Voltage Rejection vs.
Frequency (PREAMPLIFIER)
Figure 8: Quiescent Output Voltage vs. Supply
Voltage (DRIVER)
V
S
= 3V
V
O
= 330mVrms
R
L
= 10K
V
S
= 3V
R
S
= 2.2K
V
R
= 100mVrms
C
SVR
= 100
F
TDA7285
5/11
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