TS4998IQT [STMICROELECTRONICS]
2 x 1W differential input stereo audio amplifier; 2× 1W差分输入的立体声音频放大器
| 型号： | TS4998IQT |
| 厂家： | 
ST |
| 描述： | 2 x 1W differential input stereo audio amplifier |
| 文件： | 总33页 (文件大小：480K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
TS4998
2 x 1W differential input stereo audio amplifier
Features
QFN16 4x4mm
■ Operating range from V = 2.7V to 5.5V
CC
■ 1W output power per channel @ V =5V,
CC
THD+N=1%, R =8Ω
L
■ Ultra low standby consumption: 10nA typ.
■ 80dB PSRR @ 217Hz with grounded inputs
■ High SNR: 106dB(A) typ.
■ Fast startup time: 45ms typ.
■ Pop&click-free circuit
■ Dedicated standby pin per channel
■ Lead-free QFN16 4x4mm package
Pin connections (top view)
Applications
■ Cellular mobile phones
■ Notebook and PDA computers
■ LCD monitors and TVs
■ Portable audio devices
Description
The TS4998 is designed for top-class stereo
audio applications. Thanks to its compact and
power-dissipation efficient QFN16 package with
exposed pad, it suits a variety of applications.
With a BTL configuration, this audio power
amplifier is capable of delivering 1W per channel
of continuous RMS output power into an 8Ω load
@ 5V.
Each output channel (left and right), also has its
own external controlled standby mode pin to
reduce the supply current to less than 10nA per
channel. The device also features an internal
thermal shutdown protection.
The gain of each channel can be configured by
external gain setting resistors.
December 2007
Rev 1
1/33
www.st.com
33
Contents
TS4998
Contents
1
2
3
4
Typical application schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . . 21
Low frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Footprint recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Standby control and wake-up time tWU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.10 Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.11 Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.12 Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.13 Notes on PSRR measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5
6
7
QFN16 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2/33
TS4998
Typical application schematics
1
Typical application schematics
Figure 1 shows a typical application for the TS4998 with a gain of +6dB set by the input
resistors.
Figure 1.
Typical application schematics
VCC
Cs
1uF
Optional
Diff. input L- Cin1
P1
U1
Rin1
25k
TS4998
Vcc
330nF
1
2
4
3
LIN-
LOUT-
LOUT+
ROUT-
12
11
9
Left Speaker
-
Cin2
Rin2
25k
LEFT
P2
LIN+
RIN-
RIN+
+
-
8 Ohms
Diff. input L+ 330nF
Diff. input R- Cin3
Rin3
25k
Right Speaker
P3
RIGHT
330nF
ROUT+ 10
+
8 Ohms
Cin4
P4
Rin4
25k
Diff. input R+ 330nF
14
Bypass
BIAS
STBY
GND
GND
TS4998 - QFN16
1uF
Cb
Table 1.
External component descriptions
Functional description
Components
Input resistors that set the closed loop gain in conjunction with a fixed internal
feedback resistor (Gain = Rfeed/RIN, where Rfeed = 50kΩ).
RIN
Input coupling capacitors that block the DC voltage at the amplifier input
terminal. Thanks to common mode feedback, these input capacitors are
optional. However, if they are added, they form with RIN a 1st order high pass
filter with -3dB cut-off frequency (fcut-off = 1 / (2 x π x RIN x CIN)).
CIN
CS
CB
Supply bypass capacitors that provides power supply filtering.
Bypass pin capacitor that provides half supply filtering.
3/33
Absolute maximum ratings
TS4998
2
Absolute maximum ratings
Table 2.
Symbol
Absolute maximum ratings
Parameter
Value
Unit
VCC
Vin
Supply voltage (1)
6
GND to VCC
-40 to + 85
-65 to +150
150
V
V
Input voltage (2)
Toper
Tstg
Tj
Operating free air temperature range
Storage temperature
°C
°C
Maximum junction temperature
Thermal resistance junction to ambient
Power dissipation
°C
Rthja
Pd
120
°C/W
Internally limited
Human body model (3)
Digital pins STBYL, STBYR
2
1.5
ESD
ESD
kV
Machine model
200
200
V
Latch-up immunity
mA
1. All voltage values are measured with respect to the ground pin.
2. The magnitude of the input signal must never exceed VCC + 0.3V / GND - 0.3V.
3. All voltage values are measured from each pin with respect to supplies.
Table 3.
Symbol
Operating conditions
Parameter
Value
Unit
VCC
Supply voltage
2.7 to 5.5
V
V
VICM
Common mode input voltage range
GND to VCC - 1V
Standby voltage input:
VSTBY
V
Device ON
Device OFF
1.3 ≤ VSTBY ≤ VCC
GND ≤ VSTBY ≤0.4
RL
Load resistor
≥ 4
≥ 1
Ω
ROUT/GND Output resistor to GND (VSTBY = GND)
MΩ
°C
TSD
Thermal shutdown temperature
150
Thermal resistance junction to ambient
QFN16(1)
45
85
Rthja
°C/W
QFN16(2)
1. When mounted on a 4-layer PCB with vias.
2. When mounted on a 2-layer PCB with vias.
4/33
TS4998
Electrical characteristics
3
Electrical characteristics
Table 4.
Symbol
V
= +5V, GND = 0V, T
= 25°C (unless otherwise specified)
CC
amb
Parameter
Min.
Typ.
Max.
Unit
Supply current
No input signal, no load, left and right channel active
ICC
ISTBY
Voo
7.4
9.6
mA
Standby current (1)
No input signal, VSTBYL = GND, VSTBYR = GND, RL = 8Ω
10
1
2000
35
nA
mV
mW
%
Output offset voltage
No input signal, RL = 8Ω
Output power
THD = 1% max, F = 1kHz, RL = 8Ω
Po
800
1000
0.5
Total harmonic distortion + noise
Po = 700mWrms, G = 6dB, RL = 8Ω, 20Hz ≤ F ≤ 20kHz
THD + N
Power supply rejection ratio(2), inputs grounded
RL = 8Ω, G = 6dB, Cb = 1µF, Vripple = 200mVpp
F = 217Hz
F = 1kHz
PSRR
CMRR
dB
dB
80
75
Common mode rejection ratio(3)
RL = 8Ω, G = 6dB, Cb = 1µF, Vincm = 200mVpp
57
57
F = 217Hz
F = 1kHz
Signal-to-noise ratio
A-weighted, G = 6dB, Cb = 1µF, RL = 8Ω
(THD + N ≤ 0.5%, 20Hz < F < 20kHz)
SNR
108
dB
dB
Channel separation, RL = 8Ω, G = 6dB
F = 1kHz
F = 20Hz to 20kHz
Crosstalk
105
80
Output voltage noise, F = 20Hz to 20kHz, RL = 8Ω, G=6dB
Cb = 1µF
VN
µVrms
V/V
15
10
Unweighted
A-weighted
60kΩ
40kΩ
50kΩ
---------------
---------------
---------------
Gain value (RIN in kΩ)
Gain
R
R
R
IN
IN
IN
tWU
Wake-up time (Cb = 1µF)
Standby time (Cb = 1µF)
46
10
ms
µs
tSTBY
Phase margin at unity gain
RL = 8Ω, CL = 500pF
ΦM
65
Degrees
GM
Gain margin, RL = 8Ω, CL = 500pF
Gain bandwidth product, RL = 8Ω
15
dB
GBP
1.5
MHz
1. Standby mode is active when VSTBY is tied to GND.
2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the sinusoidal signal superimposed upon VCC
3. Dynamic measurements - 20*log(rms(Vout)/rms(Vincm)).
.
5/33
Electrical characteristics
TS4998
Table 5.
Symbol
V
= +3.3V, GND = 0V, T
= 25°C (unless otherwise specified)
CC
amb
Parameter
Min.
Typ.
Max.
Unit
Supply current
No input signal, no load, left and right channel active
ICC
ISTBY
Voo
6.6
8.6
mA
Standby current (1)
No input signal, VSTBYL = GND, VSTBYR = GND, RL = 8Ω
10
1
2000
35
nA
mV
mW
%
Output offset voltage
No input signal, RL = 8Ω
Output power
THD = 1% max, F = 1kHz, RL = 8Ω
Po
370
460
0.5
Total harmonic distortion + noise
Po = 300mWrms, G = 6dB, RL = 8Ω, 20Hz ≤ F ≤ 20kHz
THD + N
Power supply rejection ratio(2), inputs grounded
RL = 8Ω, G = 6dB, Cb = 1µF, Vripple = 200mVpp
F = 217Hz
F = 1kHz
PSRR
CMRR
dB
dB
80
75
Common mode rejection ratio(3)
RL = 8Ω, G = 6dB, Cb = 1µF, Vincm = 200mVpp
57
57
F = 217Hz
F = 1kHz
Signal-to-noise ratio
A-weighted, G = 6dB, Cb = 1µF, RL = 8Ω
(THD + N ≤ 0.5%, 20Hz < F < 20kHz)
SNR
104
dB
dB
Channel separation, RL = 8Ω, G = 6dB
F = 1kHz
F = 20Hz to 20kHz
Crosstalk
105
80
Output voltage noise, F = 20Hz to 20kHz, RL = 8Ω, G=6dB
Cb = 1µF
VN
µVrms
V/V
15
10
Unweighted
A-weighted
40kΩ
50kΩ
60kΩ
---------------
---------------
---------------
Gain value (RIN in kΩ)
Gain
R
R
R
IN
IN
IN
tWU
Wake-up time (Cb = 1µF)
Standby time (Cb = 1µF)
47
10
ms
µs
tSTBY
Phase margin at unity gain
RL = 8Ω, CL = 500pF
ΦM
65
Degrees
GM
Gain margin, RL = 8Ω, CL = 500pF
Gain bandwidth product, RL = 8Ω
15
dB
GBP
1.5
MHz
1. Standby mode is active when VSTBY is tied to GND.
2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the sinusoidal signal superimposed upon VCC
3. Dynamic measurements - 20*log(rms(Vout)/rms(Vincm)).
.
6/33
TS4998
Electrical characteristics
Table 6.
Symbol
V
= +2.7V, GND = 0V, T
= 25°C (unless otherwise specified)
CC
amb
Parameter
Min.
Typ.
Max.
Unit
Supply current
No input signal, no load, left and right channel active
ICC
ISTBY
Voo
6.2
8.1
mA
Standby current (1)
No input signal, VSTBYL = GND, VSTBYR = GND, RL = 8Ω
10
1
2000
35
nA
mV
mW
%
Output offset voltage
No input signal, RL = 8Ω
Output power
THD = 1% max, F = 1kHz, RL = 8Ω
Po
220
295
0.5
Total harmonic distortion + noise
Po = 200mWrms, G = 6dB, RL = 8Ω, 20Hz ≤ F ≤ 20kHz
THD + N
Power supply rejection ratio(2), inputs grounded
RL = 8Ω, G = 6dB, Cb = 1µF, Vripple = 200mVpp
F = 217Hz
F = 1kHz
PSRR
CMRR
dB
dB
76
73
Common mode rejection ratio(3)
RL = 8Ω, G = 6dB, Cb = 1µF, Vincm = 200mVpp
57
57
F = 217Hz
F = 1kHz
Signal-to-noise ratio
A-weighted, G = 6dB, Cb = 1µF, RL = 8Ω
(THD + N ≤ 0.5%, 20Hz < F < 20kHz)
SNR
102
dB
dB
Channel separation, RL = 8Ω, G = 6dB
F = 1kHz
F = 20Hz to 20kHz
Crosstalk
105
80
Output voltage noise, F = 20Hz to 20kHz, RL = 8Ω, G=6dB
Cb = 1µF
VN
µVrms
V/V
15
10
Unweighted
A-weighted
60kΩ
40kΩ
50kΩ
---------------
---------------
---------------
Gain value (RIN in kΩ)
Gain
R
R
R
IN
IN
IN
tWU
Wake-up time (Cb = 1µF)
Standby time (Cb = 1µF)
46
10
ms
µs
tSTBY
Phase margin at unity gain
RL = 8Ω, CL = 500pF
ΦM
65
Degrees
GM
Gain margin, RL = 8Ω, CL = 500pF
Gain bandwidth product, RL = 8Ω
15
dB
GBP
1.5
MHz
1. Standby mode is active when VSTBY is tied to GND.
2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the sinusoidal signal superimposed upon VCC
3. Dynamic measurements - 20*log(rms(Vout)/rms(Vincm)).
.
7/33
Electrical characteristics
TS4998
Table 7.
Index of graphics
Description
Figure
Page
THD+N vs. output power
Figure 2 to 13
Figure 14 to 19
Figure 20 to 28
Figure 29
page 9 to page 10
page 11
THD+N vs. frequency
PSRR vs. frequency
page 12 to page 13
page 13
PSRR vs. common mode input voltage
CMRR vs. frequency
Figure 30 to 35
Figure 36
page 13 to page 14
page 14
CMRR vs. common mode input voltage
Crosstalk vs. frequency
Figure 37 to 39
Figure 40 to 45
page 14 to page 15
page 15 to page 16
SNR vs. power supply voltage
Differential DC output voltage vs. common mode input
voltage
Figure 46 to 48
page 16
Current consumption vs. power supply voltage
Current consumption vs. standby voltage
Standby current vs. power supply voltage
Frequency response
Figure 49
page 16
Figure 50 to 52
Figure 53
page 17
page 17
Figure 54 to 56
Figure 57
page 17 to page 18
page 18
Output power vs. load resistance
Output power vs. power supply voltage
Power dissipation vs. output power
Power derating curves
Figure 58 to 59
Figure 60 to 62
Figure 63
page 18
page 18 to page 19
page 19
8/33
TS4998
Electrical characteristics
Figure 2.
THD+N vs. output power
Figure 3.
THD+N vs. output power
10
10
RL = 4
G = +6dB
F = 1kHz
Ω
RL = 4
G = +12dB
F = 1kHz
Ω
Vcc=5V
Vcc=5V
Cb = 1
BW < 125kHz
μF
Cb = 1
BW < 125kHz
1
μF
Vcc=3.3V
Vcc=3.3V
1
Tamb = 25°C
Tamb = 25°C
Vcc=2.7V
Vcc=2.7V
0.1
0.1
0.01
1E-3
0.01
1E-3
0.01
0.1
1
0.01
0.1
1
Output power (W)
Output power (W)
Figure 4.
THD+N vs. output power
Figure 5.
THD+N vs. output power
10
10
RL = 8
Ω
RL = 8Ω
G = +6dB
F = 1kHz
G = +12dB
F = 1kHz
Vcc=5V
Vcc=5V
Cb = 1
BW < 125kHz
μ
F
Cb = 1
BW < 125kHz
1
μF
1
Vcc=3.3V
Vcc=2.7V
Vcc=3.3V
Vcc=2.7V
Tamb = 25
°
C
Tamb = 25°C
0.1
0.1
0.01
1E-3
0.01
1E-3
0.01
0.1
1
0.01
0.1
1
Output power (W)
Output power (W)
Figure 6.
THD+N vs. output power
Figure 7.
THD+N vs. output power
10
10
RL = 16Ω
RL = 16Ω
G = +6dB
F = 1kHz
G = +12dB
F = 1kHz
Vcc=5V
Vcc=5V
Cb = 1μF
BW < 125kHz
Tamb = 25°C
Cb = 1
BW < 125kHz
1
μF
1
Tamb = 25°C
Vcc=3.3V
Vcc=2.7V
Vcc=3.3V
Vcc=2.7V
0.1
0.1
0.01
1E-3
0.01
1E-3
0.01
0.1
1
0.01
0.1
1
Output power (W)
Output power (W)
9/33
Electrical characteristics
TS4998
Figure 8.
THD+N vs. output power
Figure 9.
THD+N vs. output power
10
10
RL = 4
G = +6dB
F = 10kHz
Ω
RL = 4Ω
G = +12dB
F = 10kHz
Vcc=5V
Vcc=5V
Cb = 1
BW < 125kHz
μ
F
Cb = 1
BW < 125kHz
1
μF
Vcc=3.3V
Vcc=3.3V
1
Tamb = 25
°
C
Tamb = 25°C
Vcc=2.7V
Vcc=2.7V
0.1
0.1
0.01
1E-3
0.01
1E-3
0.01
0.1
1
0.01
0.1
1
Output power (W)
Output power (W)
Figure 10. THD+N vs. output power
Figure 11. THD+N vs. output power
10
10
RL = 8
Ω
RL = 8Ω
G = +6dB
F = 10kHz
G = +12dB
F = 10kHz
Vcc=5V
Vcc=5V
Vcc=3.3V
Vcc=2.7V
Cb = 1
μ
F
Cb = 1
BW < 125kHz
1
μF
BW < 125kHz
Tamb = 25
1
Vcc=3.3V
Vcc=2.7V
°
C
Tamb = 25°C
0.1
0.1
0.01
1E-3
0.01
1E-3
0.01
0.1
1
0.01
0.1
1
Output power (W)
Output power (W)
Figure 12. THD+N vs. output power
Figure 13. THD+N vs. output power
10
10
RL = 16Ω
G = +6dB
F = 10kHz
RL = 16Ω
G = +12dB
F = 10kHz
Vcc=5V
Vcc=5V
Cb = 1μF
BW < 125kHz
Cb = 1
BW < 125kHz
1
μF
1
Vcc=3.3V
Vcc=2.7V
Tamb = 25°C
Tamb = 25°C
Vcc=3.3V
Vcc=2.7V
0.1
0.1
0.01
1E-3
0.01
1E-3
0.01
0.1
1
0.01
0.1
1
Output power (W)
Output power (W)
10/33
TS4998
Electrical characteristics
Figure 14. THD+N vs. frequency
Figure 15. THD+N vs. frequency
10
10
RL = 4
G = +12dB
Cb = 1
BW < 125kHz
Tamb = 25
Ω
RL = 4
G = +6dB
Cb = 1
BW < 125kHz
Tamb = 25
Ω
Vcc=5V
Pout=950mW
μ
F
μ
F
Vcc=5V
Pout=950mW
°
C
°
C
1
1
Vcc=3.3V
Vcc=3.3V
Pout=430mW
Pout=430mW
0.1
0.1
0.01
Vcc=2.7V
Pout=260mW
Vcc=2.7V
Pout=260mW
0.01
100
1000
Frequency (Hz)
10000
100
1000
Frequency (Hz)
10000
Figure 16. THD+N vs. frequency
Figure 17. THD+N vs. frequency
10
10
RL = 8
G = +6dB
Cb = 1
BW < 125kHz
Tamb = 25
Ω
RL = 8
G = +12dB
Cb = 1
BW < 125kHz
Tamb = 25
Ω
μ
F
μ
F
Vcc=5V
Pout=700mW
Vcc=5V
Pout=700mW
°
C
°
C
1
1
Vcc=3.3V
Pout=300mW
Vcc=3.3V
Pout=300mW
Vcc=2.7V
Vcc=2.7V
Pout=200mW
Pout=200mW
0.1
0.1
0.01
0.01
100
1000
10000
100
1000
10000
Frequency (Hz)
Frequency (Hz)
Figure 18. THD+N vs. frequency
Figure 19. THD+N vs. frequency
10
10
RL = 16
G = +6dB
Cb = 1
BW < 125kHz
Tamb = 25
Ω
RL = 16
G = +12dB
Cb = 1
BW < 125kHz
Tamb = 25
1
Ω
μ
F
μF
Vcc=5V
Pout=450mW
Vcc=5V
Pout=450mW
°
C
°C
1
Vcc=3.3V
Pout=200mW
Vcc=3.3V
Pout=200mW
Vcc=2.7V
Vcc=2.7V
Pout=120mW
Pout=120mW
0.1
0.1
0.01
0.01
100
1000
10000
100
1000
10000
Frequency (Hz)
Frequency (Hz)
11/33
Electrical characteristics
TS4998
Figure 20. PSRR vs. frequency
Figure 21. PSRR vs. frequency
0
0
Vcc = 5V
Vripple = 200mVpp
Vcc = 5V
Vripple = 200mVpp
-10
-10
G = +6dB
Cb = 1 F, Cin = 4.7
Inputs Grounded
Tamb = 25
G = +12dB
Cb = 1 F, Cin = 4.7
Inputs Grounded
Tamb = 25
-20
-30
-40
-50
-60
-70
-80
-90
-100
-20
-30
-40
-50
-60
-70
-80
-90
-100
μ
μ
F
μ
μF
°
C
°C
100
1000
Frequency (Hz)
10000
10000
10000
100
1000
Frequency (Hz)
10000
Figure 22. PSRR vs. frequency
Figure 23. PSRR vs. frequency
0
0
Vcc = 3.3V
Vripple = 200mVpp
Vcc = 5V
Vripple = 200mVpp
-10
-10
G = +6dB
Cb = 1
Inputs Floating
Tamb = 25
μF
-20
-30
-40
-50
-60
-70
-80
-90
-100
-20
Cb = 1
Inputs Grounded
Tamb = 25
μF, Cin = 4.7μF
-30
-40
-50
-60
-70
-80
-90
-100
°
C
°
C
100
1000
100
1000
Frequency (Hz)
10000
Frequency (Hz)
Figure 24. PSRR vs. frequency
Figure 25. PSRR vs. frequency
0
0
Vcc = 3.3V
Vripple = 200mVpp
Vcc = 3.3V
Vripple = 200mVpp
-10
-10
Cb = 1
Inputs Floating
Tamb = 25
μF
G = +12dB
Cb = 1 F, Cin = 4.7
Inputs Grounded
Tamb = 25
-20
-30
-40
-50
-60
-70
-80
-90
-100
-20
-30
-40
-50
-60
-70
-80
-90
-100
μ
μF
°
C
°
C
100
1000
Frequency (Hz)
100
1000
10000
Frequency (Hz)
12/33
TS4998
Electrical characteristics
Figure 26. PSRR vs. frequency
Figure 27. PSRR vs. frequency
0
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
Vcc = 2.7V
Vripple = 200mVpp
Vcc = 2.7V
Vripple = 200mVpp
G = +12dB
-10
G = +6dB
Cb = 1 F, Cin = 4.7
Inputs Grounded
Tamb = 25
-20
-30
-40
-50
-60
-70
-80
-90
-100
μ
μ
F
Cb = 1
Inputs Grounded
Tamb = 25
μF, Cin = 4.7μF
°
C
°C
100
1000
Frequency (Hz)
10000
100
1000
Frequency (Hz)
10000
Figure 28. PSRR vs. frequency
Figure 29. PSRR vs. common mode input
voltage
0
0
Vcc = 2.7V
Vripple = 200mVpp
Vripple = 200mVpp
F = 217Hz, G = +6dB
-10
-10
Cb = 1
Inputs Floating
Tamb = 25
μF
Cb = 1μF, RL ≥ 8Ω
Tamb = 25°C
-20
-30
-40
-50
-60
-70
-80
-90
-100
-20
-30
-40
-50
-60
-70
-80
-90
°
C
Vcc=3.3V
Vcc=2.7V
Vcc=5V
100
1000
10000
0
1
2
3
4
5
Common Mode Input Voltage (V)
Frequency (Hz)
Figure 30. CMRR vs. frequency
Figure 31. CMRR vs. frequency
0
0
Vcc = 5V
Vcc = 5V
RL
G = +6dB
Vic = 200mVpp
Cb = 1
≥
8
Ω
RL ≥ 8Ω
G = +12dB
Vic = 200mVpp
-10
-20
-30
-40
-50
-60
-70
-10
-20
-30
-40
-50
-60
-70
μ
F, Cin = 4.7
μ
F
Cb = 1
μF, Cin = 4.7μF
Tamb = 25°C
Tamb = 25°C
100
1000
Frequency (Hz)
10000
100
1000
Frequency (Hz)
10000
13/33
Electrical characteristics
TS4998
Figure 32. CMRR vs. frequency
Figure 33. CMRR vs. frequency
0
0
Vcc = 3.3V
Vcc = 3.3V
RL
G = +6dB
Vic = 200mVpp
Cb = 1
≥
8
Ω
RL ≥ 8Ω
G = +12dB
Vic = 200mVpp
-10
-20
-30
-40
-50
-60
-70
-10
-20
-30
-40
-50
-60
-70
μ
F, Cin = 4.7
μ
F
Cb = 1
μF, Cin = 4.7μF
Tamb = 25°C
Tamb = 25°C
100
1000
Frequency (Hz)
10000
100
1000
Frequency (Hz)
10000
Figure 34. CMRR vs. frequency
Figure 35. CMRR vs. frequency
0
0
Vcc = 2.7V
Vcc = 2.7V
RL ≥ 8Ω
G = +6dB
Vic = 200mVpp
Cb = 1μF, Cin = 4.7μF
Tamb = 25°C
RL ≥ 8Ω
G = +12dB
Vic = 200mVpp
-10
-20
-30
-40
-50
-60
-70
-10
-20
-30
-40
-50
-60
-70
Cb = 1
μF, Cin = 4.7μF
Tamb = 25°C
100
1000
Frequency (Hz)
10000
100
1000
Frequency (Hz)
10000
Figure 36. CMRR vs. common mode input
voltage
Figure 37. Crosstalk vs. frequency
0
20
Vripple = 200mVpp
F = 217Hz, G = +6dB
RL = 4
G = +6dB
Cin = 1 F, Cb = 1
Tamb = 25
Ω
-10
-20
10
Cb = 1
μ
F, RL
≥
8
Ω
μ
μF
0
-10
-20
-30
-40
-50
-60
-70
-80
-30
Tamb = 25°C
°
C
-40
-50
Vcc=5V
Vcc=3.3V
Vcc=2.7V
-60
Vcc=3.3V
Vcc=2.7V
-70
-80
-90
-100
-110
-120
Vcc=5V
0
1
2
3
4
5
100
1000
Frequency (Hz)
10000
Common Mode Input Voltage (V)
14/33
TS4998
Electrical characteristics
Figure 38. Crosstalk vs. frequency
Figure 39. Crosstalk vs. frequency
0
0
-10
RL = 8
G = +6dB
Cin = 1 F, Cb = 1
Tamb = 25
Ω
RL = 16
G = +6dB
Cin = 1 F, Cb = 1
Tamb = 25
Ω
-10
-20
-20
μ
μ
F
μ
μF
-30
-30
°
C
°C
-40
-40
-50
-50
Vcc=5V
Vcc=5V
-60
-60
Vcc=3.3V
Vcc=2.7V
Vcc=3.3V
Vcc=2.7V
-70
-70
-80
-80
-90
-90
-100
-110
-120
-100
-110
-120
100
1000
Frequency (Hz)
10000
100
1000
Frequency (Hz)
10000
Figure 40. SNR vs. power supply voltage
Figure 41. SNR vs. power supply voltage
110
108
106
104
102
100
98
110
108
106
104
102
100
98
A - Weighted filter
96
A - weighted filter
F = 1kHz
96
F = 1kHz
94
92
90
94
92
90
G = +6dB, RL = 4
THD + N < 0.5%
Ω
G = +6dB ,RL = 8
THD + N < 0.5%
Ω
Tamb = 25
4.5 5.0
Supply Voltage (V)
°
C
Tamb = 25
4.5 5.0
Supply Voltage (V)
°C
2.5
3.0
3.5
4.0
5.5
2.5
3.0
3.5
4.0
5.5
Figure 42. SNR vs. power supply voltage
Figure 43. SNR vs. power supply voltage
110
108
106
104
102
100
98
110
108
106
104
102
100
98
A - Weighted filter
96
Unweighted filter (20Hz to 20kHz)
F = 1kHz
96
94
92
90
F = 1kHz
94
92
90
G = +6dB ,RL = 16
THD + N < 0.5%
Ω
G = +6dB, RL = 4
THD + N < 0.5%
Ω
Tamb = 25
°C
Tamb = 25
°C
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Supply Voltage (V)
Supply Voltage (V)
15/33
Electrical characteristics
TS4998
Figure 44. SNR vs. power supply voltage
Figure 45. SNR vs. power supply voltage
110
108
106
104
102
100
98
110
108
106
104
102
100
98
Unweighted filter (20Hz to 20kHz)
96
Unweighted filter (20Hz to 20kHz)
F = 1kHz
96
F = 1kHz
94
92
90
94
G = +6dB, RL = 8
THD + N < 0.5%
Ω
G = +6dB, RL = 16
THD + N < 0.5%
Ω
92
Tamb = 25
°
C
Tamb = 25
°C
90
2.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
3.0
3.5
4.0
4.5
5.0
5.5
Supply Voltage (V)
Supply Voltage (V)
Figure 46. Differential DC output voltage vs.
common mode input voltage
Figure 47. Differential DC output voltage vs.
common mode input voltage
Vcc = 5V
G = +6dB
Tamb = 25
Vcc = 3.3V
G = +6dB
Tamb = 25°C
1000
100
10
1000
100
10
°
C
1
1
0.1
0.1
0.01
1E-3
0.01
1E-3
0
1
2
3
4
5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Common Mode Input Voltage (V)
Common Mode Input Voltage (V)
Figure 48. Differential DC output voltage vs.
common mode input voltage
Figure 49. Current consumption vs. power
supply voltage
8
Vcc = 2.7V
1000
No load
G = +6dB
Tamb = 25°C
Tamb = 25°C
7
6
5
4
3
2
1
0
100
10
Both channels active
One channel active
1
0.1
0.01
1E-3
0.0
0.5
1.0
1.5
2.0
2.5
0
1
2
3
4
5
Common Mode Input Voltage (V)
Power Supply Voltage (V)
16/33
TS4998
Electrical characteristics
Figure 50. Current consumption vs. standby Figure 51. Current consumption vs. standby
voltage
voltage
8
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
Both channels active
One channel active
Both channels active
One channel active
Vcc = 5V
No load
Tamb = 25
Vcc = 3.3V
No load
°
C
Tamb = 25
°C
0
1
2
3
4
5
0.0
0.5
1.0
1.5
2.0
2.5 3.0
Standby Voltage (V)
Standby Voltage (V)
Figure 52. Current consumption vs. standby Figure 53. Standby current vs. power supply
voltage
voltage
7
6
5
4
3
2
1
0
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
No load
Tamb = 25
°
C
Both channels active
One channel active
Vcc = 2.7V
No load
Tamb = 25
°C
0.0
0.5
1.0
1.5
2.0 2.5
0
1
2
3
4
5
Standby Voltage (V)
Power Supply Voltage (V)
Figure 54. Frequency response
Figure 55. Frequency response
14
14
13
12
11
10
9
13
12
11
10
9
Cin=4.7
μ
F, Rin=12k
Ω
Cin=4.7μF, Rin=12kΩ
Cin=680nF, Rin=12k
Cin=4.7 F, Rin=24k
Ω
Cin=680nF, Rin=12k
Ω
8
8
7
7
μ
Ω
Cin=4.7 F, Rin=24kΩ
μ
6
6
5
5
4
4
Vcc = 5V
Po = 700mW
Vcc = 3.3V
Po = 300mW
3
3
Cin=330nF, Rin=24k
100
Ω
Cin=330nF, Rin=24k
100
Ω
2
2
ZL = 8
Ω + 500pF
ZL = 8
Ω + 500pF
1
1
Tamb = 25
°
C
Tamb = 25
°
C
0
0
20
20k
20
20k
10000
1000
10000
1000
Frequency (Hz)
Frequency (Hz)
17/33
Electrical characteristics
TS4998
Figure 56. Frequency response
Figure 57. Output power vs. load resistance
14
1800
1600
1400
1200
1000
800
THD+N = 1%
F = 1kHz
Cin=4.7μF, Rin=12kΩ
13
12
11
10
9
Vcc=5.5V
Vcc=5V
Cb = 1
BW < 125kHz
Tamb = 25
μF
Vcc=4.5V
Vcc=4V
Vcc=3.3V
Vcc=3V
°
C
Cin=680nF, Rin=12k
Ω
8
7
Cin=4.7μF, Rin=24kΩ
6
5
600
4
Vcc = 2.7V
Po = 200mW
400
3
Cin=330nF, Rin=24k
100
Ω
2
ZL = 8
Ω + 500pF
200
1
Vcc=2.7V
Tamb = 25
°
C
0
0
20
20k
1000
10000
4
8
12
16
20
24
28
32
Frequency (Hz)
Load Resistance (Ω)
Figure 58. Output power vs. power supply
voltage
Figure 59. Output power vs. power supply
voltage
1800
2200
F = 1kHz
Cb = 1μF
F = 1kHz
Cb = 1μF
2000
1600
1800
1600
1400
1200
1000
800
BW < 125 kHz
Tamb = 25°C
BW < 125 kHz
Tamb = 25
1400
°C
RL=4Ω
RL=4
Ω
1200
1000
800
600
400
200
0
RL=8Ω
RL=16Ω
RL=32Ω
5.0
RL=8
Ω
600
RL=16
Ω
400
200
RL=32
5.0
Ω
0
2.5
2.5
3.0
3.5
4.0
4.5
5.5
3.0
3.5
4.0
Vcc (V)
4.5
5.5
Vcc (V)
Figure 60. Power dissipation vs. output power Figure 61. Power dissipation vs. output power
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
600
550
500
450
400
350
300
250
200
150
100
50
RL=4
Ω
RL=4
Ω
RL=8
Ω
RL=8
Ω
RL=16
Ω
RL=16
Ω
Vcc = 5V
F = 1kHz
THD+N < 1%
Vcc = 3.3V
F = 1kHz
THD+N < 1%
0
0
200 400
600
800 1000 1200 1400 1600
0
100
200
300
400
500
600
700
Output Power (mW)
Output Power (mW)
18/33
TS4998
Electrical characteristics
Figure 62. Power dissipation vs. output power Figure 63. Power derating curves
400
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Mounted on 4-layer PCB
with vias
350
300
250
200
150
100
50
RL=4
Ω
Mounted on 2-layer PCB
with vias
RL=8
Ω
RL=16
Ω
Vcc = 2.7V
F = 1kHz
THD+N < 1%
No Heat sink -AMR value
0
0
25
50
75
100
C)
125
150
0
50 100 150 200 250 300 350 400 450
Ambiant Temperature (
°
Output Power (mW)
19/33
Application information
TS4998
4
Application information
4.1
General description
The TS4998 integrates two monolithic full-differential input/output power amplifiers with two
selectable standby pins dedicated for each channel. The gain of each channel is set by
external input resistors.
4.2
Differential configuration principle
The TS4998 also includes a common mode feedback loop that controls the output bias
value to average it at V /2 for any DC common mode input voltage. This allows maximum
CC
output voltage swing, and therefore, to maximize the output power. Moreover, as the load is
connected differentially instead of single-ended, output power is four times higher for the
same power supply voltage.
The advantages of a full-differential amplifier are:
●
●
●
High PSRR (power supply rejection ratio),
High common mode noise rejection,
Virtually no pops&clicks without additional circuitry, giving a faster startup time
compared to conventional single-ended input amplifiers,
●
●
Easier interfacing with differential output audio DAC,
No input coupling capacitors required due to common mode feedback loop.
In theory, the filtering of the internal bias by an external bypass capacitor is not necessary.
However, to reach maximum performance in all tolerance situations, it is recommended to
keep this option.
The only constraint is that the differential function is directly linked to external resistor
mismatching, therefore you must pay particular attention to this mismatching in order to
obtain the best performance from the amplifier.
4.3
Gain in typical application schematic
A typical differential application is shown in Figure 1 on page 3.
The value of the differential gain of each amplifier is dependent on the values of external
input resistors R
to R
and of integrated feedback resistors with fixed value. In the flat
IN1
IN4
region of the frequency-response curve (no C effect), the differential gain of each channel
IN
is expressed by the relation given in Equation 1.
Equation 1
V
O+ – VO-
Rfeed
50kΩ
RIN
AV = ------------------------------------------------------ = -------------- = -------------
diff
Diffinput+ – Diffinput-
= R expressed in kΩ and R = 50kΩ (value of internal
feed
RIN
where R = R
= R
= R
IN
IN1
IN2
IN3
IN4
feedback resistors).
20/33
TS4998
Application information
Due to the tolerance on the internal 50kΩfeedback resistors, the differential gain will be in
the range (no tolerance on R ):
IN
40kΩ
60kΩ
-------------
≤
-------------
≤AV
diff
RIN
RIN
The difference of resistance between input resistors of each channel have direct influence
on the PSRR, CMRR and other amplifier parameters. In order to reach maximum
performance, we recommend matching the input resistors R , R , R , and R with a
IN1
IN2
IN3
IN4
maximum tolerance of 1%.
Note:
For the rest of this section, Av will be called A to simplify the mathematical expressions.
diff
V
4.4
Common mode feedback loop limitations
As explained previously, the common mode feedback loop allows the output DC bias voltage
to be averaged at V /2 for any DC common mode bias input voltage.
CC
Due to the V
limitation of the input stage (see Table 3 on page 4), the common mode
ICM
feedback loop can fulfil its role only within the defined range. This range depends upon the
values of V , R and R (AV). To have a good estimation of the V value, use the
CC
IN
feed
ICM
following formula:
Equation 2
VCC × RIN + 2 × Vic × Rfeed
--------------------------------------------------------------------------
VCC × RIN + 2 × Vic × 50kΩ
--------------------------------------------------------------------------
2 × (RIN + 50kΩ)
VICM
=
=
(V)
2 × (RIN + Rfeed
)
with V in volts, R in kΩ and
CC
IN
Diffinput+ + Diffinput-
------------------------------------------------------
2
Vic
=
(V)
The result of the calculation must be in the range:
GND ≤VICM≤ VCC – 1V
Due to the +/-20% tolerance on the 50kΩ feedback resistors R
(no tolerance on R ), it is
also important to check that the VICM remains in this range at the tolerance limits:
feed
IN
VCC × RIN + 2 × Vic × 40kΩ
--------------------------------------------------------------------------
2 × (RIN + 40kΩ)
VCC × RIN + 2 × Vic × 60kΩ
--------------------------------------------------------------------------
(V)
≤VICM
≤
2 × (RIN + 60kΩ)
If the result of the V
used.
calculation is not in this range, an input coupling capacitor must be
ICM
Example: V = 2.7V, AV = 2, and V = 2.2V.
CC
ic
With internal resistors R
= 50kΩ, calculated external resistors are R = R
/AV = 25kΩ,
feed
feed
IN
V
= 2.7V and V = 2.2V, which gives V
= 1.92V. Taking into account the tolerance on
CC
ic
ICM
the feedback resistors, with R
= 40kΩ the common mode input voltage is V
= 1.87V
feed
ICM
and with R
= 60kΩ, it is V
= 1.95V.
feed
ICM
These values are not in range from GND to V - 1V = 1.7V, therefore input coupling
CC
capacitors are required. Alternatively, you can change the V value.
ic
21/33
Application information
TS4998
4.5
Low frequency response
The input coupling capacitors block the DC part of the input signal at the amplifier inputs. In
the low frequency region, C starts to have an effect. C and R form a first-order high
IN
IN
IN
pass filter with a -3dB cut-off frequency.
1
----------------------------------------------
FCL
=
(Hz)
2 × π × RIN × CIN
with R expressed in Ω and C expressed in F.
IN
IN
So, for a desired -3dB cut-off frequency we can calculate C :
IN
1
-----------------------------------------------
CIN
=
(F)
2 × π × RIN × FCL
From Figure 64, you can easily establish the C value required for a -3 dB cut-off frequency
IN
for some typical cases.
Figure 64. -3dB lower cut-off frequency vs. input capacitance
Tamb=25°C
Rin=6.2k
G~18dB
Ω
100
Rin=12k
G~12dB
Ω
10
Rin=24k
G~6dB
Ω
0.1
0.2
0.4
0.6
0.8
1
Input Capacitor Cin (
μ
F)
22/33
TS4998
Application information
4.6
Power dissipation and efficiency
Assumptions:
●
●
Load voltage and current are sinusoidal (V and I
)
out
out
Supply voltage is a pure DC source (V
)
CC
The output voltage is:
Vout = Vpeak sinωt (V)
and
Vout
------------
(A)
Iout
=
RL
and
2
Vpeak
--------------------
(W)
Pout
=
2RL
Therefore, the average current delivered by the supply voltage is:
Equation 3
Vpeak
----------------
IccAVG = 2
(A)
πRL
The power delivered by the supply voltage is:
Equation 4
Psupply = VCC IccAVG (W)
Therefore, the power dissipated by each amplifier is:
= P - P (W)
P
diss
supply
out
2 2VCC
----------------------
Pdiss
=
P
out–Pout(W)
π RL
and the maximum value is obtained when:
and its value is:
∂Pdiss
--------------------
= 0
∂Pout
Equation 5
2Vcc2
π2RL
Pdissmax =
(W)
Note:
This maximum value is only dependent on the power supply voltage and load values.
23/33
Application information
TS4998
The efficiency is the ratio between the output power and the power supply:
Equation 6
Pout
πVpeak
4Vcc
------------------ --------------------
η=
=
Psupply
The maximum theoretical value is reached when V
= V , so:
CC
peak
π
η= ---- = 78.5%
4
The TS4998 is stereo amplifier so it has two power amplifiers. Each amplifier produces heat
due to its power dissipation. Therefore, the maximum die temperature is the sum of each
amplifier’s maximum power dissipation. It is calculated as follows:
●
●
●
P
P
= Power dissipation of left channel power amplifier
= Power dissipation of right channel power amplifier
diss 1
diss 2
Total P
=P
+ P
(W)
diss 2
diss
diss 1
In most cases, P
= P
, giving:
diss 1
diss 2
4 2VCC
----------------------
TotalPdiss = 2 × Pdiss1
=
Pout–2Pout(W)
π RL
The maximum die temperature allowable for the TS4998 is 150°C. In case of overheating, a
thermal shutdown protection set to 150°C, puts the TS4998 in standby until the temperature
of the die is reduced by about 5°C.
To calculate the maximum ambient temperature T
allowable, you need to know:
amb
●
●
●
the power supply voltage value, V
CC
the load resistor value, R
L
the package type, R
THJA
Example: V =5V, R =8Ω, R QFN16=85°C/W (with 2-layer PCB with vias).
THJA
CC
L
Using the power dissipation formula given in Equation 5, the maximum dissipated power per
channel is:
P
= 633mW
dissmax
And the power dissipated by both channels is:
Total P
= 2 x P
= 1266mW
dissmax
dissmax
T
is calculated as follows:
amb
Equation 7
T
amb= 150° C – RTJHA × TotalPdissmax
Therefore, the maximum allowable value for T
is:
amb
T
= 150 - 85 x 2 x 1.266=42.4°C
amb
If a 4-layer PCB with vias is used, R
QFN16 = 45°C/W and the maximum allowable
THJA
value for T
in this case is:
amb
T
= 150 - 45 x 2 x 1.266 = 93°C
amb
24/33
TS4998
Application information
4.7
Footprint recommendation
Footprint soldering pad dimensions are given in Figure 72 on page 30. As discussed in the
previous section, the maximum allowable value for ambient temperature is dependent on
the thermal resistance junction to ambient R
power dissipation.
. Decreasing the R
value causes better
THJA
THJA
Based on best thermal performance, it is recommended to use 4-layer PCBs with vias to
effectively remove heat from the device. It is also recommended to use vias for 2-layer PCBs
to connect the package exposed pad to heatsink cooper areas placed on another layer.
For proper thermal conductivity, the vias must be plated through and solder-filled. Typical
thermal vias have the following dimensions: 1.2mm pitch, 0.3mm diameter.
Figure 65. QFN16 footprint recommendation
4.8
Decoupling of the circuit
Two capacitors are needed to correctly bypass the TS4998: a power supply bypass
capacitor C and a bias voltage bypass capacitor C .
S
b
The C capacitor has particular influence on the THD+N at high frequencies (above 7kHz)
S
and an indirect influence on power supply disturbances. With a value for C of 1µF, one can
S
expect THD+N performance similar to that shown in the datasheet.
In the high frequency region, if C is lower than 1µF, then THD+N increases and
S
disturbances on the power supply rail are less filtered.
On the other hand, if C is greater than 1µF, then those disturbances on the power supply
S
rail are more filtered.
The C capacitor has an influence on the THD+N at lower frequencies, but also impacts
b
PSRR performance (with grounded input and in the lower frequency region).
25/33
Application information
TS4998
4.9
Standby control and wake-up time tWU
The TS4998 has two dedicated standby pins (STBYL, STBYR). These pins allow to put
each channel in standby mode or active mode independently. The amplifier is designed to
reach close to zero pop when switching from one mode to the other.
When both channels are in standby (V
= V
= GND), the circuit is in shutdown
STBYR
STBYL
mode. When at least one of the two standby pins is released to put the device ON, the
bypass capacitor C starts to be charged. Because C is directly linked to the bias of the
b
b
amplifier, the bias will not work properly until the C voltage is correct. The time to reach this
b
voltage is called the wake-up time or t
and is specified in Table 4 on page 5, with C =1µF.
WU
b
During the wake-up phase, the TS4998 gain is close to zero. After the wake-up time, the
gain is released and set to its nominal value. If C has a value different from 1µF, then refer
b
to the graph in Figure 66 to establish the corresponding wake-up time.
When a channel is set to standby mode, the outputs of this channel are in high impedance
state.
Figure 66. Typical startup time vs. bypass capacitor
100
Tamb=25°C
90
80
70
60
50
40
30
Vcc=2.7V
Vcc=3.3V
Vcc=5V
0.0
0.5
1.0
1.5
2.0
2.5 3.0
3.5
F)
4.0
4.5
Bypass Capacitor Cb (
μ
4.10
Note:
4.11
Shutdown time
When the standby command is activated (both channels put into standby mode), the time
required to put the two output stages of each channel in high impedance and the internal
circuitry in shutdown mode is a few microseconds.
In shutdown mode when both channels are in standby, the Bypass pin and L +, L -, R +,
IN
IN
IN
R - pins are shorted to ground by internal switches. This allows a quick discharge of C and
IN
IN
b
C
capacitors.
Pop performance
Due to its fully differential structure, the pop performance of the TS4998 is close to perfect.
However, due to mismatching between internal resistors R , external resistors R and
feed
IN
26/33
TS4998
Application information
external input capacitors C , some noise might remain at startup. To eliminate the effect of
IN
mismatched components, the TS4998 includes pop reduction circuitry. With this circuitry,
the TS4998 is close to zero pop for all possible common applications.
In addition, when the TS4998 is in standby mode, due to the high impedance output stage in
this configuration, no pop is heard.
4.12
Single-ended input configuration
It is possible to use the TS4998 in a single-ended input configuration. However, input
coupling capacitors are needed in this configuration. The schematic diagram in Figure 67
shows an example of this configuration for a gain of +6dB set by the input resistors.
Figure 67. Typical single-ended input application
VCC
Cs
1uF
U1
Diff. input L- Cin1
P1
Rin1
25k
TS4998
Vcc
330nF
1
2
4
3
LIN-
LOUT-
LOUT+
ROUT-
12
11
9
Left Speaker
-
Cin2
Rin2
25k
LEFT
LIN+
RIN-
RIN+
+
-
8 Ohms
330nF
Diff. input R- Cin3
P2
Rin3
25k
Right Speaker
RIGHT
330nF
ROUT+ 10
+
8 Ohms
Cin4
Rin4
25k
330nF
14
Bypass
BIAS
STBY
GND
GND
TS4998 - QFN16
1uF
Cb
The component calculations remain the same for the gain. In single-ended input
configuration, the formula is:
V
O+ – VO-
--------------------------
=
Rfeed
= -------------- = -------------
RIN RIN
50kΩ
AvSE
Ve
with R expressed in kΩ.
IN
27/33
Application information
TS4998
4.13
Notes on PSRR measurement
What is the PSRR?
The PSRR is the power supply rejection ratio. The PSRR of a device is the ratio between a
power supply disturbance and the result on the output. In other words, the PSRR is the
ability of a device to minimize the impact of power supply disturbance to the output.
How is the PSRR measured?
The PSRR is measured as shown in Figure 68.
Figure 68. PSRR measurement
Vripple
Vcc
U1
Cin1
Rin1
Rin2
Rin3
Rin4
TS4998
Vcc
4.7uF
Cin2
1
2
4
3
LIN-
LOUT-
LOUT+
ROUT-
12
11
9
-
RL
8Ohms
LEFT
LIN+
RIN-
RIN+
+
-
4.7uF
Cin3
RL
8Ohms
RIGHT
4.7uF
Cin4
ROUT+ 10
+
4.7uF
14
Bypass
BIAS
STBY
GND
GND
TS4998 - QFN16
1uF
Cb
Principles of operation
●
●
●
The DC voltage supply (V ) is fixed
CC
The AC sinusoidal ripple voltage (V
) is fixed
ripple
No bypass capacitor C is used
S
The PSRR value for each frequency is calculated as:
RMS(Output)
RMS(Vripple)
PSRR = 20 × Log
(dB)
----------------------------------
RMS is an rms selective measurement.
28/33
TS4998
QFN16 package information
5
QFN16 package information
In order to meet environmental requirements, STMicroelectronics offers these devices in
®
ECOPACK packages. These packages have a Lead-free second level interconnect. The
category of second level interconnect is marked on the package and on the inner box label,
in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics
trademark. ECOPACK specifications are available at: www.st.com.
Figure 69. QFN16 package
Figure 70. QFN16 pinout (top view)
29/33
QFN16 package information
TS4998
Figure 71. QFN16 4x4mm package mechanical data
Dimensions
Millimeters (mm)
Ref
Min
Typ
0.9
Max
A
A1
A3
b
0.8
1.0
0.02
0.20
0.25
4.0
0.05
0.18
3.85
2.1
0.30
4.15
2.6
D
*
D2
E
3.85
2.1
4.0
4.15
2.6
E2
e
* The Exposed Pad is connected to Ground.
0.65
0.40
K
0.2
L
0.30
0.11
0.50
r
Figure 72. QFN16 footprint soldering pad
Footprint data
Ref
mm
A
B
C
D
E
F
4.2
4.2
0.65
0.35
0.65
2.70
30/33
TS4998
Ordering information
6
Ordering information
Table 8.
Order code
TS4998IQT
Order codes
Temperature range
-40°C to +85°C
Package
Packaging
Tape & reel
Marking
QFN16 4x4mm
K998
31/33
Revision history
TS4998
7
Revision history
Table 9.
Date
20-Dec-2007
Document revision history
Revision
Changes
1
Initial release.
32/33
TS4998
Please Read Carefully:
Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the
right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any
time, without notice.
All ST products are sold pursuant to ST’s terms and conditions of sale.
Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no
liability whatsoever relating to the choice, selection or use of the ST products and services described herein.
No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this
document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products
or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such
third party products or services or any intellectual property contained therein.
UNLESS OTHERWISE SET FORTH IN ST’S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED
WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS
OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT.
UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE, ST PRODUCTS ARE NOT
RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING
APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY,
DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE
GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER’S OWN RISK.
Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void
any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any
liability of ST.
ST and the ST logo are trademarks or registered trademarks of ST in various countries.
Information in this document supersedes and replaces all information previously supplied.
The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners.
© 2007 STMicroelectronics - All rights reserved
STMicroelectronics group of companies
Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan -
Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America
www.st.com
33/33
相关型号：
TS4999
Filter-free stereo 2.8 W class D audio power amplifier with selectable 3D sound effects
STMICROELECTR
TS4999EIJT
Filter-free stereo 2.8 W class D audio power amplifier with selectable 3D sound effects
STMICROELECTR
©2020 ICPDF网 联系我们和版权申明