TS4974
1W differential audio power amplifier
with up/down digital volume control pins
Features
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■
■
■
■
■
■
■
■
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Operates from V
CC
= 2.5 V to 5.5 V
Zero pop & click
1 W output power @ V
CC
= 5 V, THD = 1%,
F = 1 kHz, with 8
Ω
load
Ultra-low consumption in standby mode (2 µA
max.)
85 dB PSRR @ 217Hz
16-step digital volume control
Two discrete up and down volume control pins
Gain range from -33 dB to + 12 dB
Integrated debouncing system
Ultra-fast start-up time: 15 ms typ.
DFN10 3x3 mm (pitch 0.5)
VIN-
DFN10 (3x3)
Pin connections (top view)
VIN+
Applications
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Mobile phones (cellular / cordless)
PDAs
Laptop/notebook computers
Portable audio devices
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Description
At 3.3 V, the TS4974 is a dual power audio
amplifier capable of delivering 380 mW of
continuous RMS output power into a 8
Ω
bridged-
tied loads with 1% THD+N. An external standby
mode control reduces the supply current to less
than 2 µA. An internal over-temperature shutdown
protection is provided.
The TS4974 has been designed for high quality
audio applications such as mobile phones and
minimizes the number of external components
necessary.
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BYPASS
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1
2
3
4
5
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10
9
8
7
6
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t(
VCC
VOUT-
VOUT+
UP / DVC
DOWN / DVC
STANDBY
GND
The TS4974 features 16-step digital volume
control through two discrete Up and Down control
pins. The start-up gain is internally fixed to
-12 dB. An integrated debounce system prevents
voltage spikes on the UP/DOWN pins during
volume control mode from being taken into
account during a debounce time of 10 ms (typ).
May 2007
Rev 4
1/25
www.st.com
25
Contents
TS4974
Contents
1
2
3
4
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Typical application schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Low frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Assumptions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Wake-up time (t
WU
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Volume setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Notes on PSRR measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5
6
7
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
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Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
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2/25
TS4974
Absolute maximum ratings
1
Absolute maximum ratings
Table 1.
Symbol
V
CC
V
i
T
oper
T
stg
T
j
R
thja
P
d
ESD
ESD
Latch-up
Supply voltage
(1)
Input voltage
(2)
Operating free air temperature range
Storage temperature
Maximum junction temperature
Thermal resistance junction to ambient
(3)
Power dissipation
Human body model
Machine model
Latch-up immunity
Lead temperature (soldering, 10sec)
Absolute maximum ratings
Parameter
Value
6
GND to V
CC
-40 to + 85
-65 to +150
150
200
Unit
V
V
°C
°C
Internally limited
(4)
1. All voltage values are measured with respect to the ground pin.
2. The magnitude of input signal must never exceed V
CC
+ 0.3 V / GND - 0.3 V.
3. Device is protected in case of over temperature by a thermal shutdown active @ 150° C.
4. Exceeding the power derating curves during a long period, may provoke abnormal operation.
Table 2.
Symbol
V
CC
Operating conditions
Supply voltage
V
STBY
b
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P
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Standby voltage input:
Device ON
Device OFF
Volume control UP/DOWN voltage input:
UP/DOWN mode ON
UP/DOWN mode OFF
Load resistor
Thermal shutdown temperature
Thermal resistance junction to ambient
(1)
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200
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°C
°C/W
kV
V
mA
°C
200
260
Parameter
Value
2.5 to 5.5
1.5
≤
V
STBY
≤
V
CC
GND
≤
V
STBY
≤
0.4
0
≤
V
U/D
≤
0.3xV
CC,
0.7xV
CC
≤
V
U/D
≤
V
CC
≥
8
150
80
Unit
V
V
V
U/D
R
L
V
Ω
°C
°C/W
T
SD
R
thja
1. With heat sink surface = 125 mm
2
.
3/25
Typical application schematics
TS4974
2
Typical application schematics
Figure 1.
Typical application schematics for the TS4974
VCC
Rpu1
Volume DOWN
S1
470k
VCC
Rpu2
470k
VCC
Volume UP
S2
Cs
Rpd1
470k
Rpd1
470k
1µF
U1
Vin-
P1
Cin1
DIGITAL VOLUME
CONTROL
1
330nF
Cin2
Vin-
2
330nF
Vin+
Vin+
3
P2
Cb
1µF
BYP ASS
Table 3.
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ro
P
e
Rpu1, Rpu2
Rpd1, Rpd2
C
IN
External component descriptions
Functional description
Pair of pull-up (Rpu1, Rpu2) or pull down (Rpd1, Rpd2) resistors that are
connected to the digital volume control pins
UP/DVC and DOWN/DVC.
See
Section 4.9: Volume setting on page 20.
Input coupling capacitors that block the DC voltage at the amplifier input
terminal. They form together with the amplifier’s differential input impedance
Z
IN
a first order high pass filter with a -3dB cut-off frequency
(f
cut-off
= 1 / (2 x
π
x Z
IN
x C
IN
)).
See
Section 4.2: Low frequency response on page 16.
Supply bypass capacitor that provides power supply filtering.
See
Section 4.4: Decoupling of the circuit on page 19.
Bypass pin capacitor that provides half supply filtering.
See
Section 4.4: Decoupling of the circuit on page 19.
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TS4974 DFN10
O
-
STBY
4
STBY control
Components
C
S
C
B
4/25
5
GND
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BIAS
STBY
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Vout-
Vout+
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8
DOWN
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8 Ohms
UP
Vcc
10
7
6
Speaker
TS4974
Electrical characteristics
3
Table 4.
Symbol
I
CC
I
STBY
I
U/D
V
oo
P
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Electrical characteristics
V
CC
= +5 V, GND = 0 V, T
amb
= 25° C (unless otherwise specified)
Parameter
Supply current, no input signal, no load
Standby current
No input signal, V
STBY
= GND, R
L
= 8Ω
Volume control UP/DOWN current
0
≤
V
U/D
≤
0.3 V
CC
Output offset voltage
No input signal, R
L
= 8
Ω,
G=0 dB, floating inputs
Output power
THD = 1% max, f = 1 kHz, R
L
= 8Ω
0.8
Min.
Typ.
3.2
300
10
5
1
20
Max.
3.85
2000
Unit
mA
nA
µA
Total harmonic distortion + noise
THD + N Po = 500 mW rms,
20 Hz < F < 20 kHz, R
L
= 8
Ω,
G = 0 dB, C
b
= 1 µF, C
in
= 330 nF
PSRR
Power supply rejection ratio
(1)
F = 217Hz, RL = 8Ω)
V
ripple
= 200 mV
pp
, input grounded, C
b
=1 µF, C
in
=330 nF, G=0 dB
Common mode rejection ratio
(2)
F = 217 Hz, R
L
= 8
Ω,
V
incm
= 200 mV
pp
, C
b
= 1 µF, C
in
= 330 nF, G= 0 dB
Signal-to-noise ratio (weighted A, G= 0 dB)
(R
L
= 8
Ω,
THD + N
≤
0.5%, 20 Hz < F < 20 kHz)
CMRR
SNR
Gs
G
Gain step
size
Start up gain (
when powered up from V
CC
-
see
Section 4.9:
Volume setting on page 20)
Gain range
Gain
Tolerance between theoretical gain set and real gain
accuracy
O
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t
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V
N
Z
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0.5
85
61
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t(
W
%
dB
mV
dB
100
-12
-33
3
-1
10
+1
+12
dB
dB
dB
dB
dB
ms
Wake-up time
C
b
=1 µF
Output voltage noise F = 20 Hz to 20 kHz, R
L
= 8
Ω,
G= 0 dB
Unweighted
A-weighted
Differential input impedance
Debouncing time
48
21
14
60
10
220
3200
75
µV
RMS
kΩ
ms
ms
ms
t
debounce
t
autorepeat
Time between volume changes
t
range
During autorepeat mode, necessary time to cover the whole gain
range
1. Dynamic measurements - 20*log(rms(V
out
)/rms(V
ripple
)). V
ripple
is an added sinus signal to V
CC
@ F = 217 Hz.
2. Dynamic measurements - 20*log(rms(Vout)/rms(Vincm)).
5/25
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