ST TS4909 User Manual
TS4909
Dual mode low power 150mW stereo headphone amplifier
with capacitor-less and single-ended outputs
Features
■ No output coupling capacitors necessary
■ Pop-and-click noise reduction circuitry
■ Operating from V
■ Standby mode active low
■ Output power:
= 2.2V to 5.5V
CC
– 158mW @5V, into 16Ω with 1% THD+N
max (1kHz)
– 52mW @3.0V into 16Ω with 1% THD+N
max (1kHz)
■ Ultra low current consumption: 2.0mA typ.@3V
■ Ultra low standby consumption: 10nA typ.
■ High signal-to-noise ratio: 105 dB typ.@5V
■ High crosstalk immunity: 110dB (F=1kHz) for
single-ended outputs
■ PSRR: 72dB (F=1kHz), inputs grounded, for
phantom ground outputs
■ Low t
■ Available in lead-free DFN10 3x3mm
: 50ms in PHG mode, 100ms in SE mode
WU
Applications
■ Headphone amplifier
■ Mobile phone
■ PDA, portable audio player
Description
The TS4909 is a stereo audio amplifier designed
to drive headphones in portable applications.
The integrated phantom ground is a circuit
topology that eliminates the heavy output coupling
capacitors. This is of primary importance in
portable applications where space constraints are
very high. A single-ended configuration is also
available, offering even lower power consumption
because the phantom ground can be s witched off.
DFN10 (3x3)
Pin connections (top view)
Vin1
Stdby
SE/PHG
Bypass
Vin2
1
1
2
2
3
3
4
4
5
5
10
10
Vdd
9
9
Vout1
8
8
Vout3
7
7
Vout2
6
6
Gnd
Functional block diagram
SE/PHG
Vout1
Vout3
Vout2
Vin1
Stdby
Bypass
Vin2
Vdd
BIAS
Gnd
Pop-and-click noise during switch-on and switchoff phases is eliminated by integrated circuitry.
Specially designed for applications requiring low
power supplies, the TS4909 is capable of
delivering 31mW of continuous average power
into a 32Ω load with less than 1% THD+N from a
3V power supply.
Featuring an active low standby mode, the
TS4909 reduces the supply current to only 10nA
(typ.). The TS4909 is unity ga in stable an d can be
configured by external gain-setting resistors.
September 2007 Rev 8 1/32
www.st.com
32
Contents TS4909
Contents
1 Typical application schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 4
3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.2 Frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3 Gain using the typical application schematics . . . . . . . . . . . . . . . . . . . . . 23
4.4 Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.4.1 Single-ended configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.4.2 Phantom ground configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.4.3 Total power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.5 Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.6 Wake-up time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.7 Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.8 Standby mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2/32
TS4909 Typical application schematics
1 Typical application schematics
Figure 1. Typical applications for the TS4909
Rfeed1
Phantom ground configuration
Vin1
Cin1
330nF
Vin2
330nF
Cin2
Single-ended configuration
20k
20k
Rin1
Standby
Cb
1µF
20k
Rin2
20k
Rfeed2
Rfeed1
20k
BIAS
Vcc
Cs
1µF
Gnd
Vcc
Cs
1µF
SE/PHG
Vout1
Vout3
Vout2
SE/PHG
Vin1
Cin1
20k
Rin1
330nF
Standby
Cb
1µF
Vin2
330nF
20k
Rin2
Cin2
Table 1. Application component information
BIAS
Gnd
20k
Rfeed2
Component Functional description
R
C
R
feed1,2
in1,2
in1,2
C
b
C
s
Inverting input resistor that sets the closed loop gain in conjunction with R
resistor also forms a high pass filter with C
(fc = 1 / (2 x Pi x Rin x Cin)).
in
Input coupling capacitor that blocks the DC voltage at the amplifier’s input term inal.
Feedback resistor that sets the closed loop gain in conjunction with Rin.
= closed loop gain = -R
A
V
feed/Rin
.
Half supply bypass capacitor.
Supply bypass capacitor that provides power supply filtering.
Vout1
Vout3
Vout2
Cout1
Cout2
feed
. This
3/32
Absolute maximum ratings and operating conditions TS4909
2 Absolute maximum ratings and operating conditions
Table 2. Absolute maximum ratings
Symbol Parameter Value Unit
V
CC
V
T
stg
T
R
thja
P
diss
Supply voltage
Input voltage -0.3V to V
i
Storage temperature -65 to +150 °C
Maximum junction temperature 150 °C
j
Thermal resistance junction to ambient DFN10 120 °C/W
Pow e r di ssi p at ion
ESD Human body model (pin to pin) 2 kV
(1)
(2)
DFN10
6V
+0.3V V
CC
1.79 W
ESD
Machine model
220pF - 240pF (pin to pin)
200 V
Latch-up Latch-up immunity (all pins) 200 mA
Lead temperature (soldering, 10 sec) 260 °C
Output current 170
1. All voltage values are measured with respect to the ground pin.
2. Pd is calculated with T
3. Caution: this device is not protected in the event of abnormal operating conditions, such as for example,
short-circuiting between any one output pin and ground, between any one output pin and VCC, and
between individual output pins.
Table 3. Operating conditions
= 25°C, T
amb
junction
= 150°C.
(3)
Symbol Parameter Value Unit
V
T
CC
R
oper
Supply voltage 2.2 to 5.5 V
Load resistor ≥ 16 Ω
L
Operating free air temperature range -40 to + 85 °C
Load capacitor
C
L
= 16 to 100Ω
R
L
R
> 100Ω
L
400
100
Standby voltage input
V
STBY
TS4909 in STANDBY
TS4909 in active state
GND ≤ V
1.35V ≤ V
STBY
STBY
≤ 0.4
≤ V
(1)
CC
Single-ended or phantom ground configuration
V
SE/PHG
R
thja
1. The minimum current consumption (I
2. When mounted on a 4-layer PCB.
voltage Input
TS4909 outputs in single-ended configuration
TS4909 outputs in phantom ground configuration
Thermal resistance junction to ambient DFN10
) is guaranteed at ground for the whole temperature range.
STBY
(2)
V
SE/PHG=VCC
V
SE/PHG
=0
41 °C/W
mA
pF
V
V
4/32
TS4909 Electrical characteristics
3 Electrical characteristics
Table 4. Electrical characteristics at VCC = +5V with GND = 0V and T
amb
= 25°C
(unless otherwise specified)
Symbol Parameter Test conditions Min. Typ. Max. Unit
I
CC
I
STBY
P
out
THD+N
PSRR
I
out
V
O
Supply current
Standby
current
Output power
Total
harmonic
distortion +
noise
=-1)
(A
v
Pow er supply
rejection ratio
Max output
current
Output swing
No input signal, no load, single-ended
No input signal, no load, phantom ground
No input signal, R
THD+N = 1% max, F = 1kHz, R
=32Ω 10 1000 nA
L
= 32Ω, single-ended
L
THD+N = 1% max, F = 1kHz, RL = 16Ω, single-ended
THD+N = 1% max, F = 1kHz, RL = 32Ω, phantom ground
THD+N = 1% max, F = 1kHz, R
RL = 32Ω, P
RL = 16Ω, P
= 32Ω, P
R
L
RL = 16Ω, P
Inputs grounded
V
=200mVpp
ripple
= 60mW, 20Hz ≤ F ≤ 20kHz, single-ended
out
= 90mW, 20Hz ≤ F ≤ 20kHz, single-ended
out
= 60mW , 20Hz ≤ F ≤ 20kHz, phantom ground
out
= 90mW, 20Hz ≤ F ≤ 20kHz, phantom ground
out
(1)
, Av=-1, RL>=16Ω, Cb=1μF, F = 217Hz,
= 16Ω, phantom ground
L
Single-ended output referenced to phantom ground
Single-ended output referenced to ground
THD +N ≤ 1%, R
: RL = 32Ω
V
OL
: RL = 32Ω
V
OH
= 16Ω connected between out and VCC/2 140 mA
L
VOL: RL = 16Ω
VOH: RL = 16Ω
60
95
60
95
666172
4.39
4.17
2.1
3.1
88
158
85
150
0.3
0.3
0.3
0.3
67
0.14
4.75
0.25
4.55
3.2
4.8
0.47
0.69
mA
mW
%
dB
V
A-weighted, A
SNR
Signal-to-
noise ratio
20Hz ≤ F ≤ 20kHz
Single-ended
Phantom ground
R
= 32Ω, Av=-1, phantom ground
L
F = 1kHz
Cross-
talk
Channel
separation
F = 20Hz to 20kHz
= 32Ω, Av=-1, single-ended
R
L
F = 1kHz
F = 20Hz to 20kHz
OO
Output offset
voltage
Wake-up time
Phantom ground configuration, floating inputs, R
Phantom ground configuration
Single-ended configuration
V
t
WU
1. Guaranteed by design and evaluation.
=-1, RL = 32Ω, THD +N < 0.4%,
v
5/32
104
105
-73
-68
-110
-90
=22KΩ 520mV
feed
50
10080160
dB
dB
ms
Electrical characteristics TS4909
Table 5. Electrical characteristics at VCC = +3.0V
with GND = 0V, T
= 25°C (unless otherwise specified)
amb
(1)
Symbol Parameter Test conditions Min. Typ. Max. Unit
I
CC
I
STBY
P
out
THD+N
PSRR
I
out
V
O
Supply current
Standby
current
Output power
T otal harmonic
distortion +
noise
=-1)
(A
v
Power supply
rejection ratio
Max output
current
Output swing
No input signal, no load, single-ended
No input signal, no load, phantom ground
No input signal, R
THD+N = 1% max, F = 1kHz, R
=32Ω 10 1000 nA
L
= 32Ω, single-ended
L
THD+N = 1% max, F = 1kHz, RL = 16Ω, single-ended
THD+N = 1% max, F = 1kHz, R
= 32Ω, phanto m ground
L
THD+N = 1% max, F = 1kHz, RL = 16Ω, phanto m ground
R
= 32Ω, P
L
= 16Ω, P
R
L
RL = 32Ω, P
RL = 16Ω, P
Inputs grounded
V
= 200mVpp
ripple
= 25mW, 20Hz ≤ F ≤ 20kHz, single-ended
out
= 40mW, 20Hz ≤ F ≤ 20kHz, single-ended
out
= 25mW , 20Hz ≤ F ≤ 20kHz, phantom ground
out
= 40mW, 20Hz ≤ F ≤ 20kHz, phantom ground
out
(2)
, Av=-1, RL>=16Ω, Cb=1μF, F = 217 Hz,
Single-ended output referenced to phantom ground
Single-ended output referenced to ground
THD +N ≤ 1%, R
: RL = 32Ω
V
OL
: RL = 32Ω
V
OH
= 16Ω connected between out and VCC/2 82 mA
L
VOL: RL = 16Ω
VOH: RL = 16Ω
2.6
2.45
2.8
20
31
30
52
20
31
30
54
0.3
0.3
0.3
0.3
645970
65
0.12
2.83
0.19
2.70
2
2.8
mA
4.2
mW
0.34
0.49
%
dB
V
=-1, RL = 32Ω, THD +N < 0.4%, 20Hz ≤ F ≤
v
SNR
Signal-to-
noise ratio
A-weighted, A
20kHz
Single-ended
Phantom ground
= 32Ω, Av=-1, phantom ground
R
L
F = 1kHz
Cross-
talk
Channel
separation
F = 20Hz to 20kHz
= 32Ω, Av=-1, single-ended
R
L
F = 1kHz
F = 20Hz to 20kHz
OO
Output offset
voltage
Wake-up time
Phantom ground configuration, floating inputs, R
Phantom ground configuration
Single-ended configuration
feed
V
t
WU
1. All electrical values are guaranteed with correlation measurements at 2.6V and 5V.
2. Guaranteed by design and evaluation.
100
dB
101
-73
-68
dB
-110
-90
=22KΩ 520mV
50
10080160
ms
6/32
TS4909 Electrical characteristics
Table 6. Electrical characteristics at VCC = +2.6V
with GND = 0V, T
Symbol Parameter Test conditions Min. Typ. Max. Unit
= 25°C (unless otherwise specified)
amb
I
CC
I
STBY
P
out
THD+N
PSRR
I
out
V
O
Supply
current
Standby
current
Output power
Total
harmonic
distortion +
noise
=-1)
(A
v
Power supply
rejection ratio
Max output
current
Output swing
No input signal, no load, single-ended
No input signal, no load, phantom ground
No input signal, R
THD+N = 1% max, F = 1kHz, R
=32Ω 10 1000 nA
L
= 32Ω, single-ended
L
THD+N = 1% max, F = 1kHz, RL = 16Ω, single-ended
THD+N = 1% max, F = 1kHz, RL = 32Ω, phantom ground
THD+N = 1% max, F = 1kHz, R
= 32Ω, P
R
L
RL = 16Ω, P
RL = 32Ω, P
= 16Ω, P
R
L
Inputs grounded
V
= 200mVpp
ripple
= 20mW , 20Hz ≤ F ≤ 20kHz, single-ended
out
= 30mW , 20Hz ≤ F ≤ 20kHz, single-ended
out
= 20mW , 20Hz ≤ F ≤ 20kHz, phantom ground
out
= 30mW , 20Hz ≤ F ≤ 20kHz, phantom ground
out
(1)
, Av=-1, RL>=16Ω, Cb=1μF, F = 217Hz,
= 16Ω, phantom ground
L
Single-ended output referenced to phantom ground
Single-ended output referenced to ground
THD +N ≤ 1%, R
: RL = 32Ω
V
OL
: RL = 32Ω
V
OH
= 16Ω connected between out and VCC/2 70 mA
L
VOL: RL = 16Ω
VOH: RL = 16Ω
15
22
15
22
645970
2.25
2.11
1.9
2.8
23
38
23
39
0.3
0.3
0.3
0.3
65
0.11
2.45
0.18
2.32
2.7
4
0.3
0.44
mA
mW
%
dB
V
A weighted, A
SNR
Signal-to-
noise ratio
20Hz ≤ F ≤ 20kHz
Single-ended
Phantom ground
= 32Ω, Av=-1, phantom ground
R
L
F = 1kHz
Cross-
talk
Channel
separation
F = 20Hz to 20kHz
= 32Ω, Av=-1, single-ended
R
L
F = 1kHz
F = 20Hz to 20kHz
OO
Output offset
voltage
Wake-up
time
Phantom ground configuration, floating inputs, R
Phantom ground configuration
Single-ended configuration
V
t
WU
1. Guaranteed by design and evaluation.
=-1, RL = 32Ω, THD +N < 0.4%,
v
99
100
-73
-68
-110
-90
=22KΩ 520mV
feed
50
10080160
dB
dB
ms
7/32
Electrical characteristics TS4909
Table 7. Index of graphics
Description Figure
Open-loop frequency response Figure 2 to 6
Output swing vs. power supply voltage Figure 7
THD+N vs. output power Figure 8 to 23
THD+N vs. frequency Figure 24 to 31
Output power vs. power supply voltage Figure 32 to 35
Output power vs. load resistance Figure 36 to 41
Power dissipation vs. output power Figure 42 to 47
Crosstalk vs. frequency Figure 48 to 53
Signal to noise ratio vs. power supply voltage Figure 54 to 61
Pow er supply rejection ratio vs. frequency Figure 62 to 67
Current consumption vs. power supply voltage Figure 68 and 69
Current consumption vs. standby voltage Figure 70 to 75
Power derating curves Figure 76
8/32
TS4909 Electrical characteristics
Figure 2. Open-loop frequency response Figure 3. Open-loop frequency response
150
125
100
gain
phase
75
50
Gain (dB)
25
0
-25
-50
-1
10
RL=1MΩ, T
=25°C
AMB
10 10
3
5
10
Frequency (Hz)
90
45
0
-45
-90
Phase (°)
-135
-180
-225
-270
7
10
100
75
50
gain
25
0
Gain (dB)
-25
phase
-50
-75
RL=100Ω, CL=400pF, T
-100
-1
10
10 10
AMB
=25°C
3
5
10
10
Frequency (Hz)
Figure 4. Open-loop frequency response Figure 5. Open-loop frequency response
150
125
100
75
50
Gain (dB)
25
0
-25
RL=1MΩ, CL=100pF, T
-50
-1
10
gain
AMB
10 10
Frequency (Hz)
=25°C
3
10
phase
5
90
45
0
-45
-90
Phase (°)
-135
-180
-225
-270
7
10
100
75
50
gain
25
0
-25
phase
Gain (dB)
-50
-75
-100
-1
10
RL=16Ω, T
=25°C
AMB
10 10
3
5
10
10
Frequency (Hz)
90
45
0
-45
-90
-135
-180
-225
-270
7
90
45
0
-45
-90
-135
-180
-225
-270
7
Phase (°)
Phase (°)
Figure 6. Open-loop frequency response Figure 7. Output swing vs. power supply
voltage
100
75
50
25
0
Gain (dB)
-25
-50
-75
-100
-1
10
phase
RL=16Ω, CL=400pF, T
10 10
Frequency (Hz)
AMB
=25°C
3
90
45
gain
0
-45
-90
Phase (°)
-135
-180
-225
5
10
-270
7
10
6
T
=25°C
AMB
5
4
(V)
OL
3
& V
OH
V
2
RL=16
Ω
RL=32
Ω
1
0
23456
Power Supply Voltage (V)
9/32
Electrical characteristics TS4909
Figure 8. THD+N vs. output power Figure 9. THD+N vs. output power
10
Phantom Ground
F=1kHz, RL=16
Av=-1, Tamb=25°C
1
BW=20Hz-120kHz
Ω
Vcc=5V
Vcc=3V
0.1
THD+N (%)
Vcc=2.6V
0.01
1E-3
1E-3 0.01 0.1
Output Power (mW)
0.2
10
Phantom Ground
F=20kHz, RL=16
Av=-1, Tamb=25°C
BW=20Hz-120kHz
Ω
Vcc=5V
1
Vcc=3V
THD+N (%)
Vcc=2.6V
0.1
0.01
1E-3 0.01 0.1
Output Power (mW)
Figure 10. THD+N vs. output power Figure 11. THD+N vs. output power
THD+N (%)
0.01
10
Phantom Ground
F=1kHz, RL=32
Av=-1, Tamb=25°C
1
BW=20Hz-120kHz
0.1
Ω
Vcc=5V
Vcc=3V
Vcc=2.6V
THD+N (%)
10
Phantom Ground
F=20kHz, RL=32
Av=-1, Tamb=25°C
BW=20Hz-120kHz
1
0.1
Ω
Vcc=5V
Vcc=3V
Vcc=2.6V
0.2
1E-3
1E-3 0.01 0.1
Output Power (mW)
0.2
0.01
1E-3 0.01 0.1
Output Power (mW)
Figure 12. THD+N vs. output power Figure 13. THD+N vs. output power
10
Single Ended
F=1kHz, RL=16
Av=-1, Tamb=25°C
1
BW=20Hz-120kHz
Ω
Vcc=5V
Vcc=3V
0.1
THD+N (%)
Vcc=2.6V
0.01
1E-3
1E-3 0.01 0.1
Output Power (mW)
0.2
10
Single Ended
F=20kHz, RL=16
Av=-1, Tamb=25°C
BW=20Hz-120kHz
Ω
Vcc=5V
1
Vcc=3V
THD+N (%)
Vcc=2.6V
0.1
0.01
1E-3 0.01 0.1
Output Power (mW)
0.2
0.2
10/32
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