TS4994EIJT [STMICROELECTRONICS]
1.2 W differential input/output audio power amplifier with selectable standby; 1.2 W差分输入/输出音频功率放大器可选择待机
| 型号： | TS4994EIJT |
| 厂家： | 
ST |
| 描述： | 1.2 W differential input/output audio power amplifier with selectable standby |
| 文件： | 总35页 (文件大小：674K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
TS4994FC
1.2 W differential input/output audio power amplifier
with selectable standby
Features
TS4994EIJT - Flip-chip (9 bumps)
■ Differential inputs
Gnd
■ Near-zero pop & click
■ 100dB PSRR @ 217Hz with grounded inputs
■ Operating range from VCC = 2.5V to 5.5V
VO-
Bypass
VIN+
VO+
7
6
9
5
■ 1.2W rail-to-rail output power @ VCC = 5V,
THD = 1%, F = 1kHz, with 8Ωload
Stdby
VIN-
4
3
8
1
■ 90dB CMRR @ 217Hz
2
■ Ultra-low consumption in standby mode (10nA)
■ Selectable standby mode (active low or active
VCC
Stdby Mode
high)
■ Ultra fast startup time: 15ms typ.
The device is equipped with common mode
feedback circuitry allowing outputs to be always
■ Available in 9-bump flip-chip (300mm bump
diameter)
biased at V /2 regardless of the input common
CC
■ Lead-free package
mode voltage.
The TS4994 is designed for high quality audio
applications such as mobile phones and requires
few external components.
Description
The TS4994 is an audio power amplifier capable
of delivering 1W of continuous RMS output power
into an 8Ωload @ 5V. Due to its differential inputs,
it exhibits outstanding noise immunity.
Applications
■ Mobile phones (cellular / cordless)
■ Laptop / notebook computers
■ PDAs
An external standby mode control reduces the
supply current to less than 10nA. An STBY
MODE pin allows the standby to be active HIGH
or LOW. An internal thermal shutdown protection
is also provided, making the device capable of
sustaining short-circuits.
■ Portable audio devices
Order codes
Part number
Temperature range
Package
Packaging
Marking
FC9 with back
coating
TS4994EIKJT
TS4994EIJT
A94
A94
-40°C, +85°C
Tape & reel
Lead free flip-chip9
December 2006
Rev 2
1/35
www.st.com
35
Contents
TS4994FC
Contents
1
2
3
4
Application component information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . . 23
Low and high frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Calculating the influence of mismatching on PSRR performance . . . . . . 25
CMRR performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Wake-up time: tWU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4.10 Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.11 Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.12 Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5
6
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2/35
TS4994FC
Application component information
1
Application component information
Components
Functional description
Cs
Cb
Supply bypass capacitor that provides power supply filtering.
Bypass capacitor that provides half supply filtering.
Feedback resistor that sets the closed loop gain in conjunction with Rin
AV = closed loop gain = Rfeed/Rin.
Rfeed
Rin
Inverting input resistor that sets the closed loop gain in conjunction with Rfeed
.
Optional input capacitor making a high pass filter together with Rin.
(FCL = 1/(2πRinCin).
Cin
Figure 1.
Typical application
VCC
+
Cs
1u
Rfeed1
20k
2
GND
VCC
Diff. input -
Cin1
Rin1
3
Vin-
-
Vo+ 5
20k
220nF
Cin2
Rin2
Vo-
7
1
8
Vin+
GND
+
20k
220nF
8 Ohms
Diff. Input +
Bypass
Bias
+
Optional
Cb
1u
Standby
GND
6
Mode
9
Stdby
4
TS4994IJ
GND
Rfeed2
20k
GND
GNDVCC GNDVCC
3/35
Absolute maximum ratings and operating conditions
TS4994FC
2
Absolute maximum ratings and operating conditions
Table 1.
Symbol
Absolute maximum ratings
Parameter
Value
Unit
VCC
Vi
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
°C
°C/W
W
Maximum junction temperature
Thermal resistance junction to ambient (3)
Power dissipation
Rthja
Pdiss
250
internally limited
2
Human body model
kV
V
ESD
Machine model
200
Latch-up immunity
200
mA
°C
Lead temperature (soldering, 10sec)
260
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. The device is protected by a thermal shutdown active at 150°C.
Table 2.
Symbol
Operating conditions
Parameter
Value
Unit
VCC
Supply voltage
2.5 to 5.5
V
Standby mode voltage input:
VSM
V
V
Standby active LOW
Standby active HIGH
VSM=GND
VSM=VCC
Standby voltage input:
VSTBY
Device ON (VSM = GND) or device OFF (VSM = VCC
Device OFF (VSM = GND) or device ON (VSM = VCC
)
)
1.5 ≤ VSTBY ≤ VCC
GND ≤ VSTBY≤ 0.4 (1)
TSD
RL
Thermal shutdown temperature
Load resistor
150
≥ 4
°C
Ω
Rthja
Thermal resistance junction to ambient
100
°C/W
1. The minimum current consumption (ISTBY) is guaranteed when VSTBY = GND or VCC (i.e. supply rails) for the whole
temperature range.
4/35
TS4994FC
Electrical characteristics
= 25°C (unless otherwise
3
Electrical characteristics
Table 3.
Electrical characteristics for V = +5V, GND = 0V, T
CC
amb
specified)
Symbol
Parameter
Min.
Typ.
Max.
Unit
Supply current
No input signal, no load
ICC
4
7
mA
Standby current
ISTBY
No input signal, VSTBY = VSM = GND, RL = 8Ω
No input signal, VSTBY = VSM = VCC, RL = 8Ω
10
1000
nA
Differential output offset voltage
No input signal, RL = 8Ω
Voo
VICM
0.1
10
mV
V
Input common mode voltage
CMRR ≤ -60dB
0.6
0.8
VCC - 0.9
Output power
THD = 1% Max, F= 1kHz, RL = 8Ω
Pout
1.2
0.5
W
%
Total harmonic distortion + noise
Pout = 850mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
THD + N
Power supply rejection ratio with inputs grounded(1)
PSRRIG F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
100
90
dB
dB
Vripple = 200mVPP
Common mode rejection ratio
CMRR
F = 217Hz, RL = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
Vic = 200mVPP
Signal-to-noise ratio (A-weighted filter, AV = 2.5)
RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz
SNR
GBP
100
2
dB
Gain bandwidth product
RL = 8Ω
MHz
Output voltage noise, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
Unweighted, AV = 1
A-weighted, AV = 1
Unweighted, AV = 2.5
A-weighted, AV = 2.5
Unweighted, AV = 7.5
A-weighted, AV = 7.5
Unweighted, Standby
A-weighted, Standby
6
5.5
12
10.5
33
28
1.5
1
VN
μVRMS
Wake-up time(2)
Cb =1μF
tWU
15
ms
1. Dynamic measurements - 20*log(rms(Vout)/rms (Vripple)). Vripple is the super-imposed sinus signal relative to VCC
2. Transition time from standby mode to fully operational amplifier.
.
5/35
Electrical characteristics
TS4994FC
Table 4.
Electrical characteristics for V = +3.3V (all electrical values are guaranteed with
CC
correlation measurements at 2.6V and 5V), GND = 0V, T
= 25°C (unless otherwise
amb
specified)
Symbol
Parameter
Min.
Typ.
Max.
Unit
ICC
Supply current no input signal, no load
3
7
mA
Standby current
ISTBY
No input signal, VSTBY = VSM = GND, RL = 8Ω
No input signal, VSTBY = VSM = VCC, RL = 8Ω
10
1000
nA
Differential output offset voltage
No input signal, RL = 8Ω
Voo
VICM
0.1
10
mV
V
Input common mode voltage
CMRR ≤ -60dB
0.6
VCC - 0.9
Output power
THD = 1% max, F= 1kHz, RL = 8Ω
Pout
300
500
0.5
mW
%
Total harmonic distortion + noise
Pout = 300mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
THD + N
Power supply rejection ratio with inputs grounded(1)
PSRRIG F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
100
90
dB
dB
Vripple = 200mVPP
Common mode rejection ratio
CMRR
F = 217Hz, RL = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
Vic = 200mVPP
Signal-to-noise ratio (A-weighted filter, AV = 2.5)
RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz
SNR
GBP
100
2
dB
Gain bandwidth product
RL = 8Ω
MHz
Output voltage noise, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
Unweighted, AV = 1
A-weighted, AV = 1
Unweighted, AV = 2.5
A-weighted, AV = 2.5
Unweighted, AV = 7.5
A-weighted, AV = 7.5
Unweighted, Standby
A-weighted, Standby
6
5.5
12
10.5
33
28
1.5
1
VN
μVRMS
Wake-up time(2)
Cb =1μF
tWU
15
ms
1. Dynamic measurements - 20*log(rms(Vout)/rms (Vripple)). Vripple is the super-imposed sinus signal relative to VCC
2. Transition time from standby mode to fully operational amplifier.
.
6/35
TS4994FC
Table 5.
Electrical characteristics
= 25°C (unless otherwise
amb
Electrical characteristics for V = +2.6V, GND = 0V, T
CC
specified)
Symbol
Parameter
Min.
Typ.
Max.
Unit
Supply current
No input signal, no load
ICC
3
7
mA
Standby current
ISTBY
No input signal, VSTBY = VSM = GND, RL = 8Ω
No input signal, VSTBY = VSM = VCC, RL = 8Ω
10
1000
nA
Differential output offset voltage
No input signal, RL = 8Ω
Voo
VICM
0.1
10
mV
V
Input common mode voltage
CMRR ≤-60dB
0.6
V
CC- 0.9
Output power
THD = 1% max, F= 1kHz, RL = 8Ω
Pout
200
300
0.5
mW
%
Total harmonic distortion + noise
Pout = 225mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
THD + N
Power supply rejection ratio with inputs grounded(1)
PSRRIG F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
100
90
dB
dB
Vripple = 200mVPP
Common mode rejection ratio
CMRR
F = 217Hz, RL = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
Vic = 200mVPP
Signal-to-noise ratio (A-weighted filter, AV = 2.5)
RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz
SNR
GBP
100
2
dB
Gain bandwidth product
RL = 8Ω
MHz
Output voltage noise, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
Unweighted, AV = 1
A-weighted, AV = 1
Unweighted, AV = 2.5
A-weighted, AV = 2.5
Unweighted, AV = 7.5
A-weighted, AV = 7.5
Unweighted, Standby
A-weighted, Standby
6
5.5
12
10.5
33
28
1.5
1
VN
μVRMS
Wake-up time(2)
Cb =1μF
tWU
15
ms
1. Dynamic measurements - 20*log(rms(Vout)/rms (Vripple)). Vripple is the super-imposed sinus signal relative to VCC
2. Transition time from standby mode to fully operational amplifier.
.
7/35
Electrical characteristics
TS4994FC
Figure 2.
Current consumption vs. power
supply voltage
Figure 3.
Current consumption vs. standby
voltage
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
No load
Tamb=25
°
C
Standby mode=0V
Standby mode=5V
Vcc = 5V
No load
Tamb=25°C
0
1
2
3
4
5
0
1
2
3
4
5
Power Supply Voltage (V)
Standby Voltage (V)
Figure 4.
Current consumption vs. standby Figure 5.
voltage
Current consumption vs. standby
voltage
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Standby mode=0V
Standby mode=0V
Standby mode=3.3V
Standby mode=2.6V
Vcc = 3.3V
No load
Tamb=25
Vcc = 2.6V
No load
Tamb=25
°C
°C
0.0
0.6
1.2
1.8
2.4
3.0
0.0
0.6
1.2
1.8
2.4
Standby Voltage (V)
Standby Voltage (V)
Figure 6.
Differential DC output voltage vs.
common mode input voltage
Figure 7.
Power dissipation vs. output power
1000
100
10
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Av = 1
Tamb = 25
Vcc=5V
F=1kHz
THD+N<1%
°C
RL=4
Ω
Vcc=3.3V
Vcc=5V
Vcc=2.5V
1
RL=8Ω
0.1
RL=16
Ω
0.01
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Output Power (W)
Common Mode Input Voltage (V)
8/35
TS4994FC
Figure 8.
Electrical characteristics
Power dissipation vs. output power Figure 9.
Power dissipation vs. output power
0.40
0.6
0.5
0.4
0.3
0.2
0.1
Vcc=3.3V
F=1kHz
THD+N<1%
Vcc=2.6V
F=1kHz
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
RL=4Ω
THD+N<1%
RL=4Ω
RL=8Ω
RL=8
Ω
RL=16
Ω
RL=16
Ω
0.0
0.0
0.0
0.1
0.2
Output Power (W)
0.3
0.4
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Output Power (W)
Figure 10. Output power vs. power supply
voltage
Figure 11. Output power vs. power supply
voltage
2.4
2.0
RL = 4
F = 1kHz
BW < 125kHz
Tamb = 25
Ω
RL = 8Ω
F = 1kHz
BW < 125kHz
Tamb = 25°C
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
THD+N=10%
°C
THD+N=10%
THD+N=1%
THD+N=1%
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
Vcc (V)
Vcc (V)
Figure 12. Output power vs. power supply
voltage
Figure 13. Output power vs. power supply
voltage
1.2
0.6
RL = 16
Ω
RL = 32
Ω
F = 1kHz
BW < 125kHz
Tamb = 25°C
F = 1kHz
BW < 125kHz
Tamb = 25°C
1.0
0.8
0.6
0.4
0.2
0.0
0.5
0.4
0.3
0.2
0.1
0.0
THD+N=10%
THD+N=10%
THD+N=1%
THD+N=1%
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
Vcc (V)
4.5
5.0
5.5
Vcc (V)
9/35
Electrical characteristics
TS4994FC
Figure 14. Power derating curves
Figure 15. Open loop gain vs. frequency
0
1.2
60
40
20
0
Heat sink surface
(See demoboard)
≈
100mm2
1.0
Gain
-40
-80
-120
-160
-200
0.8
0.6
0.4
Phase
Vcc = 5V
ZL = 8 + 500pF
-20
-40
No Heat sink
25
0.2
0.0
Ω
Tamb = 25
°C
0.1
1
10
100
1000
10000
0
50
75
100
125
Ambiant Temperature ( C)
Frequency (kHz)
Figure 16. Open loop gain vs. frequency
Figure 17. Open loop gain vs. frequency
0
0
60
60
Gain
Gain
-40
-40
40
20
0
40
20
0
-80
-80
Phase
Phase
-120
-160
-200
-120
-160
-200
Vcc = 3.3V
ZL = 8 + 500pF
Vcc = 2.6V
ZL = 8 + 500pF
-20
-20
Ω
Ω
Tamb = 25
°C
Tamb = 25
°C
-40
0.1
-40
0.1
1
10
100
1000
10000
1
10
100
1000
10000
Frequency (kHz)
Frequency (kHz)
Figure 18. Closed loop gain vs. frequency
Figure 19. Closed loop gain vs. frequency
10
0
0
10
0
0
Phase
Phase
Gain
Gain
-40
-80
-120
-160
-200
-40
-80
-120
-160
-200
-10
-20
-30
-40
-10
-20
-30
-40
Vcc = 5V
Av = 1
ZL = 8
Vcc = 3.3V
Av = 1
ZL = 8Ω + 500pF
Ω
+ 500pF
Tamb = 25
°C
Tamb = 25
°C
0.1
1
10
100
1000
10000
0.1
1
10
100
1000
10000
Frequency (kHz)
Frequency (kHz)
10/35
TS4994FC
Electrical characteristics
Figure 20. Closed loop gain vs. frequency
Figure 21. PSRR vs. frequency
10
0
0
0
-10
-20
-30
-40
Phase
Vcc = 5V
Vripple = 200mVpp
Inputs = Grounded
Gain
-40
-80
-120
-160
-200
Av = 1, Cin = 4.7
μF
RL
≥ 8Ω
-10
-20
-30
-40
Cb=0.1μF
-50 Tamb = 25
°C
-60
-70
-80
-90
Cb=0.47μF
Cb=1μF
Vcc = 2.6V
Av = 1
ZL = 8
-100
Ω
+ 500pF
°C
Cb=0
-110
-120
Tamb = 25
0.1
1
10
100
1000
10000
20
100
1000
Frequency (Hz)
10000 20k
Frequency (kHz)
Figure 22. PSRR vs. frequency
Figure 23. PSRR vs. frequency
0
0
-10
-20
-30
-40
-10
-20
-30
-40
Vcc = 3.3V
Vripple = 200mVpp
Inputs = Grounded
Vcc = 2.6V
Vripple = 200mVpp
Inputs = Grounded
Av = 1, Cin = 4.7
μF
Av = 1, Cin = 4.7
μF
RL
≥
8Ω
RL
≥ 8Ω
Cb=0.1μF
Cb=0.1μF
-50 Tamb = 25
°C
-50 Tamb = 25
°C
-60
-70
-80
-90
-60
-70
-80
-90
Cb=0.47
μF
Cb=0.47
μF
Cb=1μF
Cb=1μF
-100
-100
Cb=0
Cb=0
-110
-120
-110
-120
20
20
100
1000
Frequency (Hz)
10000 20k
100
1000
Frequency (Hz)
10000 20k
Figure 24. PSRR vs. frequency
Figure 25. PSRR vs. frequency
0
0
-10
-20
-30
-40
-10
-20
-30
-40
Vcc = 5V
Vripple = 200mVpp
Inputs = Grounded
Vcc = 3.3V
Vripple = 200mVpp
Inputs = Grounded
Av = 2.5, Cin = 4.7
μF
Av = 2.5, Cin = 4.7
μF
RL
≥
8Ω
RL
≥ 8Ω
Cb=0.1μF
Cb=0.1μF
-50 Tamb = 25
°C
-50 Tamb = 25
°C
-60
-70
-80
-90
Cb=0.47
μF
-60
-70
-80
-90
Cb=0.47
μF
Cb=1μF
Cb=1μF
Cb=0
Cb=0
-100
-100
-110
-120
-110
-120
20
20
100
1000
Frequency (Hz)
10000 20k
100
1000
Frequency (Hz)
10000 20k
11/35
Electrical characteristics
TS4994FC
Figure 26. PSRR vs. frequency
Figure 27. PSRR vs. frequency
0
0
-10
-10
-20
-30
-40
Vcc = 5V
Vripple = 200mVpp
Inputs = Floating
Vcc = 2.6V
Vripple = 200mVpp
Inputs = Grounded
-20
-30
Rfeed = 20k
Ω
Av = 2.5, Cin = 4.7
RL
Tamb = 25
μF
-40
RL
≥ 8Ω
≥ 8Ω
Cb=0.1μF
Cb=0.1μF
-50
-50 Tamb = 25
°C
°C
-60
Cb=0.47
μF
-60
-70
-80
-90
Cb=0.47
μF
-70
Cb=1μF
Cb=1μF
-80
-90
Cb=0
-100
-110
-120
-100
Cb=0
-110
-120
20
20
100
1000
Frequency (Hz)
10000 20k
100
1000
Frequency (Hz)
10000 20k
Figure 28. PSRR vs. frequency
Figure 29. PSRR vs. frequency
0
0
-10
-20
-30
-40
-10
-20
-30
-40
Vcc = 3.3V
Vripple = 200mVpp
Inputs = Floating
Vcc = 2.6V
Vripple = 200mVpp
Inputs = Floating
Rfeed = 20k
Ω
Rfeed = 20k
Ω
RL
≥
8Ω
RL
≥ 8Ω
Cb=0.1μF
Cb=0.1μF
-50 Tamb = 25
°C
-50 Tamb = 25
°C
-60
-70
-80
-90
-60
-70
-80
-90
Cb=0.47
μF
Cb=0.47
μF
Cb=1μF
Cb=1μF
-100
-100
Cb=0
Cb=0
-110
-120
-110
-120
20
20
100
1000
Frequency (Hz)
10000 20k
100
1000
Frequency (Hz)
10000 20k
Figure 30. PSRR vs. common mode input
voltage
Figure 31. PSRR vs. common mode input
voltage
0
Vcc = 3.3V
0
-20
Vcc = 5V
Vripple = 200mVpp
Inputs Grounded
F = 217Hz
Vripple = 200mVpp
Inputs Grounded
F = 217Hz
-20
Av = 1
Av = 1
-40
RL
≥ 8Ω
-40
RL
≥ 8Ω
Cb=1
Cb=0.47
Cb=0.1
μF
Cb=1
Cb=0.47
Cb=0.1
μF
Tamb = 25
°
C
Tamb = 25
°
C
μ
F
F
μ
F
F
-60
-80
μ
-60
μ
Cb=0
Cb=0
-80
-100
-100
0.0
0.6
1.2
1.8
2.4
3.0
0
1
2
3
4
5
Common Mode Input Voltage (V)
Common Mode Input Voltage (V)
12/35
TS4994FC
Electrical characteristics
Figure 32. PSRR vs. common mode input
voltage
Figure 33. CMRR vs. frequency
0
0
Vcc = 2.5V
Vripple = 200mVpp
Inputs Grounded
F = 217Hz
-10
Vcc = 5V
-20 Vic = 200mVpp
-20
Av = 1, Cin = 470μF
-30
RL
≥ 8Ω
Cb=1μF
Av = 1
-40
≥ 8Ω
-40
-50
Tamb = 25°C
Cb=0.47μF
RL
Cb=0.1μF
Tamb = 25°C
-60
Cb=0
-60
-80
Cb=1
Cb=0.47
Cb=0.1
μF
-70
Cb=0
μ
F
-80
μF
-90
-100
-110
-120
-100
0.0
0.5
1.0
1.5
2.0
2.5
20
100
1000
Frequency (Hz)
10000 20k
10000 20k
10000 20k
Common Mode Input Voltage (V)
Figure 34. CMRR vs. frequency
Figure 35. CMRR vs. frequency
0
0
-10
-10
-20
Vcc = 2.6V
Vic = 200mVpp
Av = 1, Cin = 470
Vcc = 3.3V
-20 Vic = 200mVpp
μF
Av = 1, Cin = 470
RL
Tamb = 25
μF
-30
-40
-30
RL
≥ 8Ω
≥ 8Ω
Cb=1μF
Cb=1μF
-40
Tamb = 25
°C
°
C
Cb=0.47
μ
F
F
Cb=0.47μF
Cb=0.1
Cb=0
-50
-50
Cb=0.1
μ
μF
-60
-60
Cb=0
-70
-70
-80
-80
-90
-90
-100
-110
-120
-100
-110
-120
20
20
100
1000
10000 20k
100
1000
Frequency (Hz)
Frequency (Hz)
Figure 36. CMRR vs. frequency
Figure 37. CMRR vs. frequency
0
0
Vcc = 5V
Vic = 200mVpp
Av = 2.5, Cin = 470
Vcc = 3.3V
Vic = 200mVpp
Av = 2.5, Cin = 470μF
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
μF
RL
≥
8Ω
RL
≥ 8Ω
Tamb = 25
°
C
Tamb = 25°C
Cb=1
μF
Cb=1μF
Cb=0.47
μ
F
Cb=0.47μF
Cb=0.1μF
Cb=0.1μF
Cb=0
Cb=0
20
20
100
1000
Frequency (Hz)
10000 20k
100
1000
Frequency (Hz)
13/35
Electrical characteristics
TS4994FC
Figure 38. CMRR vs. frequency
Figure 39. CMRR vs. common mode input
voltage
0
0
-20
Vcc = 2.6V
Vic = 200mVpp
Av = 2.5, Cin = 470
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
Vcc=3.3V
Vcc=2.5V
μ
F
RL
≥ 8Ω
Tamb = 25
°C
Vic = 200mVpp
F = 217Hz
-40
Cb=1
Cb=0.47
Cb=0.1
Cb=0
μF
Av = 1, Cb = 1
RL
Tamb = 25
μF
μ
F
-60
≥ 8Ω
μF
°
C
-80
-100
Vcc=5V
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
20
100
1000
Frequency (Hz)
10000 20k
Common Mode Input Voltage (V)
Figure 40. CMRR vs. common mode input
voltage
Figure 41. THD+N vs. output power
10
0
RL = 4
F = 20Hz
Av = 1
Cb = 1μF
BW < 125kHz
Tamb = 25
Ω
Vcc=2.6V
Vcc=3.3V
Vcc=3.3V
-20
-40
Vcc=2.5V
1
0.1
Vic = 200mVpp
F = 217Hz
Av = 1, Cb = 0
Vcc=5V
°C
-60
RL
≥ 8Ω
Tamb = 25
°C
-80
-100
0.01
Vcc=5V
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
1E-3
0.01
0.1
1
Common Mode Input Voltage (V)
Output Power (W)
Figure 42. THD+N vs. output power
Figure 43. THD+N vs. output power
10
10
RL = 4
F = 20Hz
Av = 2.5
Ω
RL = 4Ω
F = 20Hz
Av = 7.5
Cb = 1μF
BW < 125kHz
Tamb = 25
Vcc=2.6V
Vcc=3.3V
Vcc=2.6V
Vcc=3.3V
Cb = 1
μ
F
1
0.1
1
0.1
BW < 125kHz
Tamb = 25
Vcc=5V
°C
°C
Vcc=5V
0.01
1E-3
0.01
1E-3
0.01
0.1
1
0.01
0.1
1
Output Power (W)
Output Power (W)
14/35
TS4994FC
Electrical characteristics
Figure 44. THD+N vs. output power
Figure 45. THD+N vs. output power
10
10
1
RL = 8
F = 20Hz
Av = 1
Ω
RL = 8Ω
F = 20Hz
Av = 2.5
Vcc=2.6V
Vcc=3.3V
Vcc=5V
Vcc=2.6V
Vcc=3.3V
Vcc=5V
1
0.1
Cb = 1
BW < 125kHz
Tamb = 25
μ
F
Cb = 1
BW < 125kHz
Tamb = 25
μF
°C
°C
0.1
0.01
0.01
1E-3
1E-3
1E-3
1E-3
0.01
0.1
1
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 46. THD+N vs. output power
Figure 47. THD+N vs. output power
10
10
RL = 8
F = 20Hz
Av = 7.5
Cb = 1μF
BW < 125kHz
Tamb = 25
Ω
RL = 16
F = 20Hz
Av = 1
Ω
Vcc=2.6V
Vcc=3.3V
Vcc=2.6V
Vcc=3.3V
Vcc=5V
1
0.1
Cb = 1
BW < 125kHz
Tamb = 25
μF
1
0.1
°C
°C
Vcc=5V
0.01
0.01
1E-3
1E-3
1E-3
0.01
0.1
1
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 48. THD+N vs. output power
Figure 49. THD+N vs. output power
10
10
Vcc=2.6V
RL = 16
F = 20Hz
Av = 2.5
Ω
RL = 16Ω
F = 20Hz
Av = 7.5
Vcc=2.6V
Vcc=3.3V
Vcc=3.3V
1
0.1
1
0.1
Cb = 1
BW < 125kHz
Tamb = 25
μF
Cb = 1
BW < 125kHz
Tamb = 25
μF
Vcc=5V
°C
°C
Vcc=5V
0.01
1E-3
0.01
1E-3
1E-3
0.01
0.1
1
1E-3
0.01
0.1
1
Output Power (W)
Output Power (W)
15/35
Electrical characteristics
TS4994FC
Figure 50. THD+N vs. output power
Figure 51. THD+N vs. output power
10
10
RL = 4
F = 1kHz
Av = 1
Cb = 1μF
BW < 125kHz
Tamb = 25
Ω
RL = 4
F = 1kHz
Av = 2.5
Cb = 1μF
BW < 125kHz
Ω
Vcc=2.6V
Vcc=3.3V
Vcc=2.6V
Vcc=3.3V
1
0.1
1
0.1
Vcc=5V
°C
Tamb = 25
°C
Vcc=5V
0.01
0.01
1E-3
1E-3
0.01
0.1
1
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 52. THD+N vs. output power
Figure 53. THD+N vs. output power
10
10
RL = 4
F = 1kHz
Av = 7.5
Ω
RL = 8Ω
F = 1kHz
Av = 1
Cb = 1μF
BW < 125kHz
Tamb = 25
Vcc=2.6V
Vcc=3.3V
Vcc=2.6V
Vcc=3.3V
Cb = 1
μ
F
1
0.1
BW < 125kHz
Tamb = 25
Vcc=5V
1
°C
°C
Vcc=5V
0.1
0.01
1E-3
0.01
0.1
1
1E-3
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 54. THD+N vs. output power
Figure 55. THD+N vs. output power
10
10
RL = 8
Ω
RL = 8Ω
F = 1kHz
Av = 2.5
F = 1kHz
Av = 7.5
Cb = 1μF
BW < 125kHz
Vcc=2.6V
Vcc=3.3V
Vcc=2.6V
Vcc=3.3V
Cb = 1μF
1
0.1
1
0.1
BW < 125kHz
Tamb = 25
°C
Tamb = 25
°C
Vcc=5V
Vcc=5V
0.01
0.01
1E-3
1E-3
0.01
0.1
1
0.01
0.1
1
Output Power (W)
Output Power (W)
16/35
TS4994FC
Electrical characteristics
Figure 56. THD+N vs. output power
Figure 57. THD+N vs. output power
10
10
1
Vcc=2.6V
Vcc=3.3V
RL = 16
F = 1kHz
Av = 1
Ω
RL = 16Ω
F = 1kHz
Av = 2.5
Vcc=2.6V
Vcc=3.3V
1
0.1
Cb = 1
BW < 125kHz
Tamb = 25
μF
Cb = 1
BW < 125kHz
Tamb = 25
μF
Vcc=5V
°C
°C
Vcc=5V
0.1
0.01
0.01
1E-3
1E-3
1E-3
1E-3
0.01
0.1
1
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 58. THD+N vs. output power
Figure 59. THD+N vs. output power
10
10
RL = 4
F = 20kHz
Av = 1
Cb = 1μF
BW < 125kHz
Tamb = 25
Ω
RL = 16
F = 1kHz
Av = 7.5
Cb = 1μF
BW < 125kHz
Tamb = 25
Ω
Vcc=2.6V
Vcc=3.3V
Vcc=2.6V
Vcc=3.3V
1
0.1
1
0.1
Vcc=5V
°C
°C
Vcc=5V
0.01
0.01
1E-3
0.01
0.1
1
1E-3
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 60. THD+N vs. output power
Figure 61. THD+N vs. output power
10
10
Vcc=2.6V
RL = 4
F = 20kHz
Av = 2.5
Ω
RL = 4Ω
F = 20kHz
Av = 7.5
Vcc=2.6V
Vcc=3.3V
Vcc=5V
Vcc=3.3V
Cb = 1
BW < 125kHz
Tamb = 25
μ
F
Cb = 1
BW < 125kHz
Tamb = 25
μF
Vcc=5V
°C
°C
1
1
0.1
1E-3
0.1
1E-3
0.01
0.1
1
0.01
0.1
1
Output Power (W)
Output Power (W)
17/35
Electrical characteristics
TS4994FC
Figure 62. THD+N vs. output power
Figure 63. THD+N vs. output power
10
10
RL = 8
F = 20kHz
Ω
RL = 8Ω
F = 20kHz
Vcc=2.6V
Av = 1
Cb = 1
BW < 125kHz
Tamb = 25
Av = 2.5
Vcc=2.6V
Vcc=3.3V
Vcc=3.3V
Vcc=5V
μF
Cb = 1μF
BW < 125kHz
Tamb = 25°C
1
1
°C
Vcc=5V
0.1
0.1
1E-3
0.01
0.1
1
1E-3
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 64. THD+N vs. output power
Figure 65. THD+N vs. output power
10
10
RL = 8
F = 20kHz
Av = 7.5
Ω
RL = 16
F = 20kHz
Av = 1
Cb = 1μF
BW < 125kHz
Tamb = 25
Ω
Vcc=2.6V
Vcc=3.3V
Vcc=2.6V
Vcc=3.3V
Cb = 1
BW < 125kHz
Tamb = 25
μF
1
0.1
°C
°C
1
Vcc=5V
Vcc=5V
0.1
0.01
1E-3
1E-3
0.01
0.1
1
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 66. THD+N vs. output power
Figure 67. THD+N vs. output power
10
10
RL = 16
F = 20kHz
Av = 2.5
Ω
RL = 16Ω
F = 20kHz
Av = 7.5
Vcc=2.6V
Vcc=2.6V
Vcc=3.3V
Vcc=5V
Vcc=3.3V
Vcc=5V
Cb = 1μF
Cb = 1
BW < 125kHz
Tamb = 25
μF
1
0.1
BW < 125kHz
Tamb = 25
°C
°C
1
0.1
0.01
1E-3
0.01
0.1
1
1E-3
0.01
0.1
1
Output Power (W)
Output Power (W)
18/35
TS4994FC
Electrical characteristics
Figure 68. THD+N vs. frequency
Figure 69. THD+N vs. frequency
10
10
RL = 4
Av = 1
Cb = 1
Bw < 125kHz
Tamb = 25
Ω
RL = 4
Av = 7.5
Cb = 1
Bw < 125kHz
Tamb = 25
Ω
μF
μF
1
0.1
1
Vcc=2.6V, Po=350mW
°C
°C
0.1
0.01
Vcc=2.6V, Po=350mW
0.01
1E-3
Vcc=5V, Po=1W
100
Vcc=5V, Po=1W
100
20
1000
10000 20k
20
1000
10000 20k
Frequency (Hz)
Frequency (Hz)
Figure 70. THD+N vs. frequency
Figure 71. THD+N vs. frequency
10
10
RL = 8
Av = 1
Cb = 1
Bw < 125kHz
Tamb = 25
Ω
RL = 8
Av = 7.5
Cb = 1
Bw < 125kHz
Ω
μF
μF
1
0.1
1
0.1
°C
Tamb = 25°C
Vcc=2.6V, Po=225mW
Vcc=5V, Po=850mW
Vcc=5V, Po=850mW
0.01
1E-3
Vcc=2.6V, Po=225mW
0.01
20
100
1000
10000 20k
20
100
1000
Frequency (Hz)
10000 20k
Frequency (Hz)
Figure 72. THD+N vs. frequency
Figure 73. THD+N vs. frequency
10
10
RL = 16
Av = 1
Ω
RL = 16
Av = 7.5
Cb = 1μF
Bw < 125kHz
Tamb = 25
Ω
Cb = 1μF
1
0.1
1
0.1
Bw < 125kHz
Tamb = 25
°C
°C
Vcc=5V, Po=600mW
Vcc=2.6V, Po=155mW
0.01
1E-3
0.01
1E-3
Vcc=5V, Po=600mW
Vcc=2.6V, Po=155mW
20
100
1000
10000 20k
20
100
1000
Frequency (Hz)
10000 20k
Frequency (Hz)
19/35
Electrical characteristics
TS4994FC
Figure 74. THD+N vs. output power
Figure 75. THD+N vs. output power
10
10
RL = 4
Ω
RL = 4Ω
Vcc = 5V
Av = 1
Cb = 0
BW < 125kHz
Tamb = 25°C
Vcc = 5V
Av = 7.5, Cb = 0
BW < 125kHz
F=20kHz
F=1kHz
F=20kHz
F=1kHz
1
0.1
Tamb = 25°C
1
F=20Hz
F=20Hz
0.1
0.01
1E-3
0.01
0.1
1
1E-3
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 76. THD+N vs. output power
Figure 77. THD+N vs. output power
10
10
RL = 4
Ω
RL = 4Ω
Vcc = 2.6V
Vcc = 2.6V
Av = 1, Cb = 0
BW < 125kHz
F=20kHz
Av = 7.5, Cb = 0
BW < 125kHz
Tamb = 25°C
1
0.1
Tamb = 25
°C
1
F=20kHz
F=20Hz
F=1kHz
F=1kHz
0.1
0.01
F=20Hz
1E-3
1E-3
0.01
Output Power (W)
0.1
1E-3
0.01
Output Power (W)
0.1
Figure 78. THD+N vs. output power
Figure 79. THD+N vs. output power
10
10
RL = 8
Ω
RL = 8Ω
Vcc = 5V
Av = 1
Cb = 0
BW < 125kHz
Tamb = 25°C
Vcc = 5V
Av = 7.5, Cb = 0
BW < 125kHz
F=20kHz
F=1kHz
F=20kHz
F=1kHz
1
0.1
1
0.1
Tamb = 25°C
F=20Hz
0.01
F=20Hz
0.01
0.01
1E-3
1E-3
0.01
0.1
1
0.1
1
Output Power (W)
Output Power (W)
20/35
TS4994FC
Electrical characteristics
Figure 80. THD+N vs. output power
Figure 81. THD+N vs. output power
10
10
RL = 8
Ω
RL = 8Ω
Vcc = 2.6V
Vcc = 2.6V
Av = 1, Cb = 0
BW < 125kHz
Av = 7.5, Cb = 0
BW < 125kHz
Tamb = 25°C
1
0.1
F=20kHz
1
Tamb = 25
°C
F=20kHz
F=1kHz
F=1kHz
0.1
0.01
0.01
F=20Hz
F=20Hz
1E-3
1E-3
0.01
Output Power (W)
0.1
1E-3
0.01
Output Power (W)
0.1
Figure 82. THD+N vs. output power
Figure 83. THD+N vs. output power
10
10
RL = 16
Ω
RL = 16Ω
Vcc = 5V
Vcc = 5V
Av = 1, Cb = 0
BW < 125kHz
Av = 7.5, Cb = 0
BW < 125kHz
Tamb = 25°C
1
0.1
F=20kHz
F=1kHz
1
0.1
F=20kHz
F=1kHz
Tamb = 25
°C
0.01
F=20Hz
F=20Hz
0.01
1E-3
1E-3
0.01
0.1
1
1E-3
0.01
0.1
1
Output Power (W)
Output Power (W)
Figure 84. THD+N vs. output power
Figure 85. THD+N vs. output power
10
10
RL = 16
Ω
RL = 16Ω
Vcc = 2.6V
Vcc = 2.6V
Av = 1, Cb = 0
BW < 125kHz
Av = 7.5, Cb = 0
BW < 125kHz
Tamb = 25°C
1
0.1
F=20kHz
F=1kHz
1
0.1
Tamb = 25
°C
F=20kHz
F=20Hz
F=1kHz
0.01
1E-3
F=20Hz
0.01
1E-3
0.01
Output Power (W)
0.1
1E-3
0.01
Output Power (W)
0.1
21/35
Electrical characteristics
TS4994FC
Figure 86. SNR vs. power supply voltage with Figure 87. SNR vs. power supply voltage with
unweighted filter A-weighted filter
110
105
100
95
110
105
100
95
RL=16
Ω
RL=16
Ω
RL=8Ω
RL=4Ω
RL=8Ω
RL=4Ω
90
90
Av = 2.5
Cb = 1
THD+N < 0.7%
Av = 2.5
Cb = 1μF
THD+N < 0.7%
Tamb = 25
μ
F
85
85
Tamb = 25
°
C
°C
80
80
2.5
3.0
3.5
4.0
4.5
5.0
2.5
3.0
3.5
4.0
4.5
5.0
Power Supply Voltage (V)
Power Supply Voltage (V)
Figure 88. Startup time vs. bypass capacitor
20
Tamb=25°C
Vcc=5V
15
10
5
Vcc=3.3V
Vcc=2.6V
0
0.0
0.4
0.8
1.2
1.6
2.0
Bypass Capacitor Cb ( F)
22/35
TS4994FC
Application information
4
Application information
4.1
Differential configuration principle
The TS4994 is a monolithic full-differential input/output power amplifier. The TS4994 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 the device to always have a
CC
maximum output voltage swing, and by consequence, maximize the output power.
Moreover, as the load is connected differentially, compared to a single-ended topology, the
output is four times higher for the same power supply voltage.
The advantages of a full-differential amplifier are:
●
●
●
Very high PSRR (power supply rejection ratio).
High common mode noise rejection.
Virtually zero pop without additional circuitry, giving a faster start-up time compared
with 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. But, to reach maximum performance in all tolerance situations, it is better to
keep this option.
The main disadvantage is:
●
As the differential function is directly linked to the mismatch between external resistors,
paying particular attention to this mismatch is mandatory in order to get the best
performance from the amplifier.
4.2
Gain in typical application schematic
A typical differential application is shown in Figure 1 on page 3.
In the flat region of the frequency-response curve (no C effect), the differential gain is
in
expressed by the relation:
V
O+ – VO
Rfeed
Rin
AV = ------------------------------------------------------ = --------------
diff
Diffinput+ – Diffinput-
where R = R = R and R
= R
= R
.
in
in1
in2
feed
feed1
feed2
Note:
For the rest of this section, Av will be called A to simplify the expression.
diff V
4.3
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
However, due to V
limitation of the input stage (see Table 3 on page 5), the common
ICM
mode feedback loop can play its role only within a defined range. This range depends upon
23/35
Application information
TS4994FC
the values of V , R and R
(AV). To have a good estimation of the V value, use the
ICM
CC
in
feed
following formula:
VCC × Rin + 2 × Vic × Rfeed
-------------------------------------------------------------------------
VICM
=
(V)
2 × (Rin + Rfeed
)
with
Diffinput+ + Diffinput-
------------------------------------------------------
2
Vic
=
(V)
The result of the calculation must be in the range:
0.6V ≤VICM≤ VCC – 0.9V
If the result of the V
used.
calculation is not in this range, an input coupling capacitor must be
ICM
Example: With V =2.5V, R = R
= 20k and V = 2V, we find V
= 1.63V. This is
ICM
CC
in
feed
ic
higher than 2.5V - 0.9V = 1.6V, so input coupling capacitors are required. Alternatively, you
can change the V value.
ic
4.4
Low and high frequency response
In the low frequency region, C starts to have an effect. C forms, with R , a high-pass filter
in
in
in
with a -3dB cut-off frequency. F is in Hz.
CL
1
FCL
=
(Hz)
2× π×Rin ×Cin
In the high-frequency region, you can limit the bandwidth by adding a capacitor (C
) in
feed
parallel with R
. It forms a low-pass filter with a -3dB cut-off frequency. F is in Hz.
feed
CH
1
FCH
=
(Hz)
2× π×Rfeed ×Cfeed
While these bandwidth limitations are in theory attractive, in practice, because of low
performance in terms of capacitor precision (and by consequence in terms of mismatching),
they deteriorate the values of PSRR and CMRR.
The influence of mismatching on PSRR and CMRR performance is discussed in more detail
in the following sections.
Example: A typical application with input coupling and feedback capacitor with F = 50Hz
CL
and F = 8kHz. We assume that the mismatching between R
and C
can be
CH
in1,2
feed1,2
neglected. If we sweep the frequency from DC to 20kHz we observe the following with
respect to the PSRR value:
●
From DC to 200Hz, the C impedance decreases from infinite to a finite value and the
in
C
impedance is high enough to be neglected. Due to the tolerance of C
, we
feed
in1,2
24/35
TS4994FC
Application information
must introduce a mismatch factor (R x C ≠ R x C ) that will decrease the PSRR
in1
in
in2
in2
performance.
●
●
From 200Hz to 5kHz, the C impedance is low enough to be neglected when
in
compared with R and the C
impedance is high enough to be neglected as well. In
in,
feed
this range, we can reach the PSRR performance of the TS4994 itself.
From 5kHz to 20kHz, the C impedance is low to be neglected when compared to R
in
in,
and the C
impedance decreases to a finite value. Due to tolerance of C
, we
feed
feed1,2
introduce a mismatching factor (R
PSRR performance.
x C
≠ R
x C
) that will decrease the
feed1
feed1
feed2
feed2
4.5
Calculating the influence of mismatching on PSRR
performance
For calculating PSRR performance, we consider that C and C
have no influence. We
feed
in
use the same kind of resistor (same tolerance) and ΔR is the tolerance value in %.
The following PSRR equation is valid for frequencies ranging from DC to about 1kHz.
The PSRR equation is (ΔR in %):
⎡
⎢
⎣
⎤
⎥
⎦
ΔR×100
(10000 − ΔR2)
PSRR ≤ 20 ×Log
(dB)
This equation doesn't include the additional performance provided by bypass capacitor
filtering. If a bypass capacitor is added, it acts, together with the internal high output
impedance bias, as a low-pass filter, and the result is a quite important PSRR improvement
with a relatively small bypass capacitor.
The complete PSRR equation (ΔR in %, C in microFarad and F in Hz) is:
b
ΔR × 100
--------------------------------------------------------------------------------------------------------
PSRR ≤20 × log
(dB)
2
2
2
(1000 – ΔR ) × 1 + F × C × 22.2
b
Example: With ΔR = 0.1% and C = 0, the minimum PSRR is -60dB. With a 100nF bypass
b
capacitor, at 100Hz the new PSRR would be -93dB.
This example is a worst case scenario, where each resistor has extreme tolerance. It
illustrates the fact that with only a small bypass capacitor, the TS4994 provides high PSRR
performance.
Note also that this is a theoretical formula. Because the TS4994 has self-generated noise,
you should consider that the highest practical PSRR reachable is about -110dB. It is
therefore unreasonable to target a -120dB PSRR.
25/35
Application information
TS4994FC
The three following graphs show PSRR versus frequency and versus bypass capacitor C in
b
worst-case conditions (ΔR = 0.1%).
Figure 89. PSRR vs. frequency (worst case
Figure 90. PSRR vs. frequency (worst case
conditions)
conditions)
0
-10
-20
0
-10
-20
Vcc = 3.3V, Vripple = 200mVpp
Av = 1, Cin = 4.7
Vcc = 5V, Vripple = 200mVpp
Av = 1, Cin = 4.7μF
μF
-30
-30
ΔR/R = 0.1%, RL ≥ 8Ω
ΔR/R = 0.1%, RL ≥ 8Ω
Tamb = 25°C, Inputs = Grounded
-40
-40
Tamb = 25°C, Inputs = Grounded
Cb=0
Cb=0
-50
-50
-60
-60
-70
-70
Cb=0.1μF
Cb=0.1μF
-80
-80
-90
-90
-100
-110
-120
-130
-140
-100
-110
-120
-130
-140
Cb=1
μF
Cb=0.47
μ
F
Cb=1
μF
Cb=0.47μF
20
20
100
1000
10000 20k
100
1000
10000 20k
Frequency (Hz)
Frequency (Hz)
Figure 91. PSRR vs. frequency (worst case
conditions)
0
-10
-20
Vcc = 2.5V, Vripple = 200mVpp
Av = 1, Cin = 4.7
μF
-30
ΔR/R = 0.1%, RL ≥ 8Ω
Tamb = 25°C, Inputs = Grounded
-40
Cb=0
-50
-60
-70
Cb=0.1μF
-80
-90
-100
-110
-120
-130
-140
Cb=1
μF
Cb=0.47μF
20
100
1000
10000 20k
Frequency (Hz)
26/35
TS4994FC
Application information
The two following graphs show typical applications of the TS4994 with a random selection of
four ΔR/R values with a 0.1% tolerance.
Figure 92. PSRR vs. frequency with random
choice condition
Figure 93. PSRR vs. frequency with random
choice condition
0
0
-10
-20
-10
-20
Vcc = 5V, Vripple = 200mVpp
Av = 1, Cin = 4.7
R/R 0.1%, RL
Tamb = 25 C, Inputs = Grounded
Vcc = 2.5V, Vripple = 200mVpp
Av = 1, Cin = 4.7
R/R 0.1%, RL
Tamb = 25 C, Inputs = Grounded
μ
≥
F
8
μF
≥ 8Ω
Δ
≤
Ω
Δ
≤
-30
-30
°
°
-40
-40
-50
-50
-60
-60
Cb=0
Cb=0
Cb=0.1μF
Cb=0.1μF
-70
-70
-80
-80
-90
-90
-100
-110
-120
-130
-140
-100
-110
-120
-130
-140
Cb=1
μF
Cb=0.47
μ
F
Cb=1
μF
Cb=0.47μF
20
20
100
1000
10000 20k
100
1000
10000 20k
Frequency (Hz)
Frequency (Hz)
4.6
CMRR performance
For calculating CMRR performance, we consider that C and C
have no influence. C
b
in
feed
has no influence in the calculation of the CMRR.
We use the same kind of resistor (same tolerance) and ΔR is the tolerance value in %.
The following CMRR equation is valid for frequencies ranging from DC to about 1kHz.
The CMRR equation is (ΔR in %):
⎡
⎢
⎣
⎤
⎥
⎦
ΔR × 200
(10000 − ΔR2 )
CMRR ≤ 20 × Log
(dB)
Example: With ΔR = 1%, the minimum CMRR is -34dB.
This example is a worst case scenario where each resistor has extreme tolerance. Ut
illustrates the fact that for CMRR, good matching is essential.
As with the PSRR, due to self-generated noise, the TS4994 CMRR limitation is about
-110dB.
Figure 94 and Figure 95 show CMRR versus frequency and versus bypass capacitor C in
b
worst-case conditions (ΔR=0.1%).
27/35
Application information
TS4994FC
Figure 94. CMRR vs. frequency (worst case
conditions)
Figure 95. CMRR vs. frequency (worst case
conditions)
0
0
-10
-20
-30
-40
-50
-60
Vcc = 2.5V
Vic = 200mVpp
Av = 1, Cin = 470μF
Vcc = 5V
-10 Vic = 200mVpp
Av = 1, Cin = 470
R/R = 0.1%, RL
Tamb = 25
μF
≥ 8Ω
ΔR/R = 0.1%, RL
≥ 8Ω
Δ
-20
-30
-40
-50
-60
Tamb = 25
°C
°
C
Cb=1
Cb=0
μ
F
Cb=1μF
Cb=0
20
20
100
1000
Frequency (Hz)
10000 20k
100
1000
Frequency (Hz)
10000 20k
Figure 96 and Figure 97 show CMRR versus frequency for a typical application with a
random selection of four ΔR/R values with a 0.1% tolerance.
Figure 96. CMRR vs. frequency with random Figure 97. CMRR vs. frequency with random
selection condition selection condition
0
0
Vcc = 5V
Vic = 200mVpp
Vcc = 2.5V
Vic = 200mVpp
-10
-10
-20 Av = 1, Cin = 470
R/R 0.1%, RL
Tamb = 25
μ
≥
F
8
-20 Av = 1, Cin = 470
R/R 0.1%, RL
Tamb = 25
μF
≥ 8Ω
Δ
≤
Ω
Δ
≤
-30
-40
-50
-60
-70
-80
-90
-30
-40
-50
-60
-70
-80
-90
°C
°C
Cb=1
Cb=0
μF
Cb=1
Cb=0
μF
20
20
100
1000
Frequency (Hz)
10000 20k
100
1000
Frequency (Hz)
10000 20k
4.7
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 = V
sinωt (V)
peak
and
Vout
------------
Iout
=
(A)
RL
28/35
TS4994FC
Application information
and
2
Vpeak
--------------------
(W)
Pout
=
2RL
Therefore, the average current delivered by the supply voltage is:
Equation 1
Vpeak
----------------
(A)
ICC
= 2
AVG
The power delivered by the supply voltage is:
Psupply = VCC ⋅ ICC
πRL
(W)
AVG
Therefore, the power dissipated by each amplifier is:
Pdiss = Psupply – Pout (W)
Equation 2
2 2VCC
----------------------
Pout–Pout
Pdiss
=
π RL
and the maximum value is obtained when:
∂Pdiss
----------------- = 0
∂Pout
and its value is:
Equation 3
2Vcc2
π2RL
Pdissmax =
(W)
Note:
This maximum value is only dependent on the power supply voltage and load values.
The efficiency is the ratio between the output power and the power supply:
Equation 4
Pout
πVpeak
4VCC
------------------ --------------------
η=
=
Psupply
The maximum theoretical value is reached when V
= V , so:
CC
peak
π
----
η=
= 78.5%
4
The maximum die temperature allowable for the TS4994 is 125°C. However, in case of
overheating, a thermal shutdown set to 150°C, puts the TS4994 in standby until the
temperature of the die is reduced by about 5°C.
29/35
Application information
TS4994FC
To calculate the maximum ambient temperature T
allowable, you need to know:
amb
●
●
●
The value of the power supply voltage, V
CC
The value of the load resistor, R
L
The R
value for the package type
thja
Example: V = 5V, R = 8Ω, R
= 100°C/W (100mm² copper heatsink)
CC
L
thja-flipchip
Using the power dissipation formula given above in Equation 3 this gives a result of:
= 633mW
P
dissmax
T
is calculated as follows:
amb
Equation 5
T
amb= 125° C – RTJHA × Pdissmax
Therefore, the maximum allowable value for T is:
amb
T
= 125-80x0.633=62°C
amb
4.8
Decoupling of the circuit
Two capacitors are needed to correctly bypass the TS4994. A power supply bypass
capacitor C and a bias voltage bypass capacitor Cb.
s
C has particular influence on the THD+N in the high frequency region (above 7kHz) and an
s
indirect influence on power supply disturbances. With a value for C of 1µF, you can expect
s
similar THD+N performance to that shown in the datasheet.
In the high frequency region, if C is lower than 1µF, it increases THD+N, and disturbances
s
on the power supply rail are less filtered.
On the other hand, if C is higher than 1µF, the disturbances on the power supply rail are
s
more filtered.
C has an influence on THD+N at lower frequencies, but its function is critical to the final
b
result of PSRR (with input grounded and in the lower frequency region).
4.9
Wake-up time: tWU
When the standby is released to put the device ON, the bypass capacitor C is not charged
b
immediately. As C is directly linked to the bias of the amplifier, the bias will not work
b
properly until the C voltage is correct. The time to reach this voltage is called the wake-up
b
time or t
and is specified in Table 3 on page 5, with C =1µF. During the wake-up time, the
WU
b
TS4994 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 other than 1µF, refer to the graph in Figure 88 on page 22 to establish the
b
wake-up time.
30/35
TS4994FC
Application information
4.10
Shutdown time
When the standby command is set, the time required to put the two output stages in high
impedance and the internal circuitry in shutdown mode is a few microseconds.
Note:
In shutdown mode, the Bypass pin and Vin+, Vin- pins are short-circuited to ground by
internal switches. This allows a quick discharge of the C and C capacitors.
b
in
4.11
Pop performance
Due to its fully differential structure, the pop performance of the TS4994 is close to perfect.
However, due to mismatching between internal resistors R , R , and external input
in
feed
capacitors C , some noise might remain at startup. To eliminate the effect of mismatched
in
components, the TS4994 includes pop reduction circuitry. With this circuitry, the TS4994 is
close to zero pop for all possible common applications.
In addition, when the TS4994 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 TS4994 in a single-ended input configuration. However, input
coupling capacitors are needed in this configuration. The schematic in Figure 98 shows an
example of this configuration.
Figure 98. Single-ended input typical application
VCC
+
Cs
1u
Rfeed1
20k
2
GND
VCC
Ve
Cin1
Rin1
3
Vin-
-
Vo+
Vo-
5
7
20k
220nF
Cin2
Rin2
1
8
Vin+
+
20k
+
220nF
8 Ohms
GND
Bypass
Bias
Cb
1u
Standby
GND
6
Mode
9
Stdby
4
TS4994IJ
GND
Rfeed2
20k
GND
GNDVCC GND VCC
The component calculations remain the same, except for the gain. In single-ended input
configuration, the formula is:
VO+ − VO− Rfeed
AvSE
=
=
Ve
Rin
31/35
Package information
TS4994FC
5
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.
Flip-chip package (9 bumps)
Dimensions in millimeters unless otherwise indicated.
Figure 99. Pinout (top view)
Gnd
VO-
Bypass
VIN+
VO+
7
6
9
5
Stdby
VIN-
4
3
8
1
2
VCC
Stdby Mode
* Balls are underneath
Figure 100. Marking (top view)
E
A94
YWW
32/35
TS4994FC
Package information
Figure 101. Dimensions
●
●
●
●
Die size: 1.63mm x 1.63mm ± 30µm
1.63 mm
Die height (including bumps): 600µm
Bumps diameter: 315µm ±50µm
Bump diameter before reflow: 300µm
±10µm
1.63 mm
●
●
●
●
●
Bump height: 250µm ±40µm
Back coating height: 40µm ±10µm
Die height: 350µm ±20µm
Pitch: 500µm ±50µm
0.5mm
0.5mm
Coplanarity: 60µm max
∅ 0.25mm
100µm
600µm
Figure 102. Tape & reel dimensions
1.5
4
1
1
A
A
8
Die size X + 70µm
4
All dimensions are in mm
User direction of feed
33/35
Revision history
TS4994FC
6
Revision history
Table 6.
Date
Document revision history
Revision
Changes
17-Mar-2005
12-Dec-2006
1
2
Initial release.
Template update.
34/35
TS4994FC
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35/35
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