TS4994
1W differential input/output audio power amplifier
with selectable standby
Features
Pin connections (top view)
■
Differential inputs
■
Near-zero pop & click
■
100dB PSRR @ 217Hz with grounded inputs
■
Operating range from VCC = 2.5V to 5.5V
■
1W rail-to-rail output power @ VCC = 5V,
THD = 1%, F = 1kHz, with 8Ω load
■
90dB CMRR @ 217Hz
■
Ultra-low consumption in standby mode (10nA)
■
Selectable standby mode (active low or active
high)
■
Ultra fast startup time: 15ms typ.
■
Available in DFN10 3x3 (0.5mm pitch) &
MiniSO-8
■
All lead-free packages
TS4994IQT - DFN10
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 (except in the MiniSO-8 version). An
internal thermal shutdown protection is also
provided, making the device capable of sustaining
short-circuits.
The device is equipped with common mode
feedback circuitry allowing outputs to be always
1
10
VO+
VIN -
2
9
VDD
STBY MODE
3
8
N/C
VIN +
4
7
GND
BYPASS
5
6
VO-
TS4994IST - MiniSO-8
Description
The TS4994 is an audio power amplifier capable
of delivering 1W of continuous RMS output power
into an 8Ω load @ 5V. Due to its differential inputs,
it exhibits outstanding noise immunity.
STBY
STBY
1
8
VIN-
2
7
Vcc
VO+
VIN+
3
6
GND
BYPASS
4
5
VO-
biased at VCC/2 regardless of the input common
mode voltage.
The TS4994 is designed for high quality audio
applications such as mobile phones and requires
few external components.
Applications
■
Mobile phones (cellular / cordless)
■
Laptop / notebook computers
■
PDAs
■
Portable audio devices
Order codes
Part number
Temperature range
TS4994IQT
Package
DFN10
-40°C to +85°C
TS4994IST
December 2006
Packing
Marking
K994
Tape & reel
MiniSO-8
Rev 6
K994
1/35
www.st.com
35
Contents
TS4994
Contents
1
Application component information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 5
3
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5
6
2/35
4.1
Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.2
Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.3
Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.4
Low and high frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.5
Calculating the influence of mismatching on PSRR performance . . . . . . 23
4.6
CMRR performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.7
Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.8
Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.9
Wake-up time: tWU
4.10
Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.11
Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.12
Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.13
Demoboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.1
DFN10 package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.2
MiniSO-8 package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
TS4994
Application component information
Components
Functional description
Cs
Supply bypass capacitor that provides power supply filtering.
Cb
Bypass capacitor that provides half supply filtering.
Rfeed
Feedback resistor that sets the closed loop gain in conjunction with Rin
AV = closed loop gain = Rfeed/Rin.
Rin
Inverting input resistor that sets the closed loop gain in conjunction with Rfeed.
Cin
Optional input capacitor making a high pass filter together with Rin.
(FCL = 1/(2πRinCin).
Figure 1.
Typical application, DFN10 version
VCC
+
Rfeed1
20k
9
Cs
1u
GND
VCC
Cin1
+
Diff. input -
220nF 20k
Cin2 Rin2
+
GND
Rin1
220nF 20k
Diff. Input +
Optional
+
1
Application component information
2 Vin-
-
4 Vin+
+
Vo+ 10
Vo6
8 Ohms
5 Bypass
Bias
Cb
1u
Standby
Mode
Stdby
GND
1
7
GND
3
GND
TS4994IQ
Rfeed2
20k
GND VCC
GND VCC
3/35
Application component information
Figure 2.
TS4994
Typical application, MiniSO-8 version
VCC
+
Rfeed1
20k
7
Cs
1u
GND
VCC
Cin1
+
Diff. input -
220nF 20k
Cin2 Rin2
+
GND
Rin1
2 Vin-
-
3 Vin+
+
Vo+ 8
Vo5
220nF 20k
8 Ohms
4 Bypass
+
Diff. Input +
Optional
Bias
Cb
1u
Standby
Stdby
GND
1
6
GND
GND
TS4994IS
Rfeed2
20k
GND VCC
4/35
TS4994
Absolute maximum ratings and operating conditions
2
Absolute maximum ratings and operating conditions
Table 1.
Absolute maximum ratings
Symbol
VCC
Vi
Parameter
Supply voltage (1)
Input voltage
(2)
Value
Unit
6
V
GND to VCC
V
Toper
Operating free air temperature range
-40 to + 85
°C
Tstg
Storage temperature
-65 to +150
°C
150
°C
120
215
°C/W
internally limited
W
2
kV
Machine model
200
V
Latch-up immunity
200
mA
Lead temperature (soldering, 10sec)
260
°C
Value
Unit
Tj
Maximum junction temperature
Rthja
Thermal resistance junction to ambient
DFN10
MiniSO-8
Pdiss
Power dissipation
(3)
Human body model
ESD
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.
Operating conditions
Symbol
Parameter
VCC
Supply voltage
2.5 to 5.5
V
VSM
Standby mode voltage input:
Standby active LOW
Standby active HIGH
VSM=GND
VSM=VCC
V
1.5 ≤ VSTBY ≤ VCC
GND ≤ VSTBY≤ 0.4 (1)
V
VSTBY
Standby voltage input:
Device ON (VSM = GND) or device OFF (VSM = VCC)
Device OFF (VSM = GND) or device ON (VSM = VCC)
TSD
Thermal shutdown temperature
150
°C
RL
Load resistor
≥8
Ω
Thermal resistance junction to ambient
DFN10 (2)
MiniSO-8
80
190
°C/W
Rthja
1. The minimum current consumption (ISTBY) is guaranteed when VSTBY = GND or VCC (i.e. supply rails) for the whole
temperature range.
2. When mounted on a 4-layer PCB.
5/35
Electrical characteristics
TS4994
3
Electrical characteristics
Table 3.
Electrical characteristics for VCC = +5V, GND = 0V, Tamb = 25°C (unless otherwise
specified)
Symbol
ICC
ISTBY
Voo
Parameter
Min.
Typ.
Max.
Unit
Supply current
No input signal, no load
4
7
mA
Standby current
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
0.1
10
mV
VCC - 0.9
V
VICM
Input common mode voltage
CMRR ≤ -60dB
0.6
Pout
Output power
THD = 1% Max, F= 1kHz, RL = 8Ω
0.8
1
W
THD + N
Total harmonic distortion + noise
Pout = 850mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
0.5
%
PSRRIG
Power supply rejection ratio with inputs grounded(1)
F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
Vripple = 200mVPP
100
dB
CMRR
Common mode rejection ratio
F = 217Hz, RL = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
Vic = 200mVPP
90
dB
SNR
Signal-to-noise ratio (A-weighted filter, AV = 2.5)
RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz
100
dB
GBP
Gain bandwidth product
RL = 8Ω
2
MHz
VN
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
tWU
Wake-up time(2)
Cb =1μF
6
5.5
12
10.5
33
28
1.5
1
15
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
μVRMS
ms
TS4994
Table 4.
Electrical characteristics
Electrical characteristics for VCC = +3.3V (all electrical values are guaranteed with
correlation measurements at 2.6V and 5V), GND = 0V, Tamb = 25°C (unless otherwise
specified)
Symbol
ICC
ISTBY
Voo
Parameter
Min.
Typ.
Max.
Unit
Supply current no input signal, no load
3
7
mA
Standby current
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
0.1
10
mV
VCC - 0.9
V
VICM
Input common mode voltage
CMRR ≤ -60dB
0.6
Pout
Output power
THD = 1% max, F= 1kHz, RL = 8Ω
300
380
mW
THD + N
Total harmonic distortion + noise
Pout = 300mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
0.5
%
PSRRIG
Power supply rejection ratio with inputs grounded(1)
F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
Vripple = 200mVPP
100
dB
CMRR
Common mode rejection ratio
F = 217Hz, RL = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
Vic = 200mVPP
90
dB
SNR
Signal-to-noise ratio (A-weighted filter, AV = 2.5)
RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz
100
dB
GBP
Gain bandwidth product
RL = 8Ω
2
MHz
VN
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
tWU
Wake-up time(2)
Cb =1μF
6
5.5
12
10.5
33
28
1.5
1
15
μVRMS
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
Table 5.
Electrical characteristics for VCC = +2.6V, GND = 0V, Tamb = 25°C (unless otherwise
specified)
Symbol
ICC
ISTBY
Voo
TS4994
Parameter
Min.
Typ.
Max.
Unit
Supply current
No input signal, no load
3
7
mA
Standby current
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
0.1
10
mV
VCC- 0.9
V
VICM
Input common mode voltage
CMRR ≤-60dB
0.6
Pout
Output power
THD = 1% max, F= 1kHz, RL = 8Ω
200
250
mW
THD + N
Total harmonic distortion + noise
Pout = 225mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
0.5
%
PSRRIG
Power supply rejection ratio with inputs grounded(1)
F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
Vripple = 200mVPP
100
dB
CMRR
Common mode rejection ratio
F = 217Hz, RL = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF
Vic = 200mVPP
90
dB
SNR
Signal-to-noise ratio (A-weighted filter, AV = 2.5)
RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz
100
dB
GBP
Gain bandwidth product
RL = 8Ω
2
MHz
VN
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
tWU
Wake-up time(2)
Cb =1μF
6
5.5
12
10.5
33
28
1.5
1
15
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.
8/35
μVRMS
ms
TS4994
Electrical characteristics
Current consumption vs. power
supply voltage
Figure 4.
4.0
4.0
No load
3.5 Tamb=25°C
3.5
Current Consumption (mA)
Current Consumption (mA)
Figure 3.
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Current consumption vs. standby
voltage
3.0
Standby mode=0V
2.5
Standby mode=5V
2.0
1.5
1.0
Vcc = 5V
No load
Tamb=25°C
0.5
0
1
2
3
4
0.0
5
0
1
2
Power Supply Voltage (V)
Current consumption vs. power
supply voltage
Figure 6.
3.5
3.0
3.0
2.5
2.5
Standby mode=0V
Standby mode=3.3V
2.0
1.5
1.0
Vcc = 3.3V
No load
Tamb=25°C
0.5
0.0
0.0
0.6
1.2
1.8
2.4
Current Consumption (mA)
Current Consumption (mA)
Figure 5.
4
5
Standby mode=0V
Standby mode=2.6V
2.0
1.5
1.0
Vcc = 2.6V
No load
Tamb=25°C
0.5
0.0
0.0
3.0
Current consumption vs. standby
voltage
0.6
Standby Voltage (V)
Figure 7.
3
Standby Voltage (V)
1.2
1.8
2.4
Standby Voltage (V)
Differential DC output voltage vs.
common mode input voltage
Figure 8.
Power dissipation vs. output power
1000
Av = 1
Tamb = 25°C
Voo (mV)
Power Dissipation (W)
0.6
100
Vcc=3.3V
Vcc=2.5V
10
Vcc=5V
1
RL=8Ω
0.4
0.2
RL=16Ω
0.1
0.01
0.0
Vcc=5V
F=1kHz
THD+N
