ETC TS4890IS

TS4890
RAIL TO RAIL OUTPUT 1W AUDIO POWER AMPLIFIER WITH
STANDBY MODE
■ OPERATING FROM VCC = 2.2V to 5.5V
■ 1W RAI L TO RAIL OUTPUT POWER @
PIN CONNECTIONS (Top View)
Vcc=5V, THD=1%, f=1kHz, with 8Ω Load
TS4890IS, TS4890IST - MiniSO8
■ ULTRA LOW CONSUMPTION IN STANDBY
MODE (10nA)
■ 75dB PSRR @ 217Hz from 5 to 2.2V
■ POP & CLICK REDUCTION CIRCUITRY
■ ULTRA LOW DISTORTION (0.1%)
■ UNITY GAIN STABLE
■ AVAILABLE IN MiniSO8 & SO8
Standby
1
8
VOUT2
Bypass
2
7
GND
VIN+
3
6
VCC
VIN-
4
5
VOUT1
DESCRIPTION
The TS4890 (MiniSO8 & SO8) is an Audio Power
Amplifier capable of delivering 1W of continuous
RMS. ouput power into 8Ω load @ 5V.
This Audio Amplifier is exhibiting 0.1% distortion
level (THD) from a 5V supply for a Pout = 250mW
RMS. An external standby mode control reduces
the supply current to less than 10nA. An internal
thermal shutdown protection is also provided.
The TS4890 have been designed for high quality
audio applications such as mobile phones and to
minimize the number of external components.
TS4890ID, TS4890IDT - SO8
Standby
1
8
VOUT2
Bypass
2
7
GND
VIN+
3
6
VCC
VIN-
4
5
VOUT1
The unity-gain stable amplifier can be configured
by external gain setting resistors.
APPLICATIONS
TYPICAL APPLICATION SCHEMATIC
■ Mobile Phones (Cellular / Cordless)
■ Laptop / Notebook Computers
■ PDAs
■ Portable Audio Devices
Cfeed
Rfeed
ORDER CODE
TS4890IST
TS4890IDT
Rin
-40, +85°C
S
3
VinVin+
-
Vout1 5
+
RL
8 Ohms
Vcc
D
•
•
4
2
Bypass
1
Standby
Av=-1
+
Rstb
Cb
Vout2
8
Bias
GND
Part Number
Package
Cs
Vcc
Audio
Input
Cin
Temperature
Range
Vcc
6
TS4890
7
S = MiniSO Package (MiniSO) - also available in Tape & Reel (ST)
D = Small Outline Package (SO) - also available in Tape & Reel (DT)
November 2001
1/31
TS4890
ABSOLUTE MAXIMUM RATINGS
Symbol
VCC
Vi
Supply voltage
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
Tj
R thja
Pd
ESD
ESD
1.
2.
3.
4.
Parameter
1)
Maximum Junction Temperature
Thermal Resistance Junction to
SO8
MiniSO8
°C/W
Ambient3)
175
215
See Power Derating Curves
Fig. 24
2
200
Class A
260
Power Dissipation 4)
Human Body Model
Machine Model
Latch-up Immunity
Lead Temperature (soldering, 10sec)
W
kV
V
°C
All voltages values are measured with respect to the ground pin.
The magnitude of input signal must never exceed VCC + 0.3V / GND - 0.3V
Device is protected in case of over temperature by a thermal shutdown active @ 150°C.
Exceeding the power derating curves during a long period may involve abnormal working of the device.
OPERATING CONDITIONS
Symbol
Parameter
Value
Unit
VCC
Supply Voltage
2.2 to 5.5
V
VICM
Common Mode Input Voltage Range
GND + 1V to VCC
V
VSTB
Standby Voltage Input :
Device ON
Device OFF
1.5 ≤ VSTB ≤ V CC
GND ≤ V STB ≤ 0.5
V
RL
R thja
Load Resistor
4 - 32
Thermal Resistance Junction to Ambient
SO8
MiniSO8
1. This thermal resistance can be reduced with a suitable PCB layout (see Power Derating Curves Fig. 24)
2/31
Ω
°C/W
1)
150
190
TS4890
ELECTRICAL CHARACTERISTICS
VCC = +5V, GND = 0V, Tamb = 25°C (unless otherwise specified)
Symbol
Typ.
Max.
Unit
Supply Current
No input signal, no load
6
8
mA
Standby Current 1)
No input signal, Vstdby = GND, RL = 8Ω
10
1000
nA
Voo
Output Offset Voltage
No input signal, RL = 8Ω
5
20
mV
Po
Output Power
THD = 1% Max, f = 1kHz, RL = 8Ω
1
W
0.15
%
Power Supply Rejection Ratio2)
f = 217Hz, RL = 8Ω, RFeed = 22KΩ, Vripple = 200mV rms
77
dB
ΦM
Phase Margin at Unity Gain
RL = 8Ω, CL = 500pF
70
Degrees
GM
Gain Margin
RL = 8Ω, CL = 500pF
20
dB
GBP
Gain Bandwidth Product
RL = 8Ω
2
MHz
ICC
ISTANDBY
THD + N
PSRR
Parameter
Min.
Total Harmonic Distortion + Noise
Po = 250mW rms, Gv = 2, 20Hz < f < 20kHz, RL = 8Ω
1. Standby mode is actived when Vstdby is tied to GND
2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the surimposed sinus signal to Vcc @ f = 217Hz
VCC = +3.3V, GND = 0V, Tamb = 25°C (unless otherwise specified)
Symbol
Typ.
Max.
Unit
Supply Current
No input signal, no load
5.5
8
mA
Standby Current 1)
No input signal, Vstdby = GND, RL = 8Ω
10
1000
nA
Voo
Output Offset Voltage
No input signal, RL = 8Ω
5
20
mV
Po
Output Power
THD = 1% Max, f = 1kHz, RL = 8Ω
450
mW
Total Harmonic Distortion + Noise
Po = 250mW rms, Gv = 2, 20Hz < f < 20kHz, RL = 8Ω
0.15
%
Power Supply Rejection Ratio2)
f = 217Hz, RL = 8Ω, RFeed = 22KΩ, Vripple = 200mV rms
77
dB
ΦM
Phase Margin at Unity Gain
RL = 8Ω, CL = 500pF
70
Degrees
GM
Gain Margin
RL = 8Ω, CL = 500pF
20
dB
GBP
Gain Bandwidth Product
RL = 8Ω
2
MHz
ICC
ISTANDBY
THD + N
PSRR
Parameter
Min.
1. Standby mode is actived when Vstdby is tied to GND
2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the surimposed sinus signal to Vcc @ f = 217Hz
3/31
TS4890
VCC = 2.6V, GND = 0V, Tamb = 25°C (unless otherwise specified)
Symbol
Typ.
Max.
Unit
Supply Current
No input signal, no load
5
8
mA
Standby Current 1)
No input signal, Vstdby = GND, RL = 8Ω
10
1000
nA
Voo
Output Offset Voltage
No input signal, RL = 8Ω
5
20
mV
Po
Output Power
THD = 1% Max, f = 1kHz, RL = 8Ω
260
mW
Total Harmonic Distortion + Noise
Po = 200mW rms, Gv = 2, 20Hz < f < 20kHz, RL = 8Ω
0.15
%
Power Supply Rejection Ratio2)
f = 217Hz, RL = 8Ω, RFeed = 22KΩ, Vripple = 200mV rms
77
dB
ΦM
Phase Margin at Unity Gain
RL = 8Ω, CL = 500pF
70
Degrees
GM
Gain Margin
RL = 8Ω, CL = 500pF
20
dB
GBP
Gain Bandwidth Product
RL = 8Ω
2
MHz
ICC
ISTANDBY
THD + N
PSRR
Parameter
Min.
1. Standby mode is actived when Vstdby is tied to GND
2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the surimposed sinus signal to Vcc @ f = 217Hz
VCC = 2.2V, GND = 0V, Tamb = 25°C (unless otherwise specified)
Symbol
Typ.
Max.
Unit
Supply Current
No input signal, no load
5
8
mA
Standby Current 1)
No input signal, Vstdby = GND, RL = 8Ω
10
1000
nA
Voo
Output Offset Voltage
No input signal, RL = 8Ω
5
20
mV
Po
Output Power
THD = 1% Max, f = 1kHz, RL = 8Ω
180
mW
Total Harmonic Distortion + Noise
Po = 200mW rms, Gv = 2, 20Hz < f < 20kHz, RL = 8Ω
0.15
%
Power Supply Rejection Ratio2)
f = 217Hz, RL = 8Ω, RFeed = 22KΩ, Vripple = 100mV rms
77
dB
ΦM
Phase Margin at Unity Gain
RL = 8Ω, CL = 500pF
70
Degrees
GM
Gain Margin
RL = 8Ω, CL = 500pF
20
dB
GBP
Gain Bandwidth Product
RL = 8Ω
2
MHz
ICC
ISTANDBY
THD + N
PSRR
Parameter
Min.
1. Standby mode is actived when Vstdby is tied to GND
2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the surimposed sinus signal to Vcc @ f = 217Hz
4/31
TS4890
Components
Functiona l Description
Rin
Inverting input resistor which sets the closed loop gain in conjunction with Rfeed. This resistor also
forms a high pass filter with Cin (fc = 1 / (2 x Pi x Rin x Cin))
Cin
Input coupling capacitor which blocks the DC voltage at the amplifier input terminal
Rfeed
Feed back resistor which sets the closed loop gain in conjunction with Rin
Cs
Supply Bypass capacitor which provides power supply filtering
Cb
Bypass pin capacitor which provides half supply filtering
Cfeed
Rstb
Gv
Low pass filter capacitor allowing to cut the high frequency
(low pass filter cut-off frequency 1 / (2 x Pi x Rfeed x Cfeed))
Pull-down resistor which fixes the right supply level on the standby pin
Closed loop gain in BTL configuration = 2 x (Rfeed / Rin)
REMARKS
1. All measurements, except PSRR measurements, are made with a supply bypass capacitor Cs = 100µF.
1. External resistors are not needed for having better stability when supply @ Vcc down to 3V. The
quiescent current still remains the same.
2. The standby response time is about 1µs.
5/31
TS4890
Fig. 1 : Open Loop Frequency Response
Fig. 2 : Open Loop Frequency Response
0
-80
Gain (dB)
20
-100
-120
0
-140
40
Gain (dB)
-60
Phase
Vcc = 5V
ZL = 8 Ω + 560pF
Tamb = 25 C
Gain
-40
Phase (Deg)
40
60
-80
20
-100
-120
0
-140
-160
-180
-20
-180
-200
-40
0.3
1
10
100
1000
10000
-200
-220
-40
0.3
1
10
Fig. 3 : Open Loop Frequency Response
0
Vcc = 3.3V
RL = 8Ω
Tamb = 25 C
10000
80
-40
-60
-100
-120
20
-140
0
Vcc = 3.3V
ZL = 8Ω + 560pF
Tamb = 25 C
Gain
60
-160
Phase (Deg)
Phase
-20
Phase
100
1000
10000
-140
-160
-180
-20
-200
-220
-240
-40
0.3
1
10
Frequency (kHz)
80
1000
10000
80
0
-20
Vcc = 2.6V
ZL = 8Ω + 560pF
Tamb = 25 C
Gain
-40
60
-60
-100
20
-120
-140
0
-160
40
Gain (dB)
Phase
-200
-100
20
-120
-140
0
-160
-180
-200
-20
-220
1
10
100
Frequency (kHz)
6/31
1000
10000
-240
-40
-80
Phase
-180
-20
-20
-60
-80
Phase (Deg)
Gain (dB)
40
-40
0.3
-240
Fig. 6 : Open Loop Frequency Response
0
Vcc = 2.6V
RL = 8Ω
Tamb = 25 C
Gain
100
Frequency (kHz)
Fig. 5 : Open Loop Frequency Response
60
-60
-120
-220
10
-40
-100
20
0
-200
1
-20
-80
40
-180
-40
0.3
-220
0
-20
-80
40
Gain (dB)
1000
Fig. 4 : Open Loop Frequency Response
Gain (dB)
80
Gain
100
Frequency (kHz)
Frequency (kHz)
60
-40
-60
Phase
-160
-20
-20
Phase (Deg)
Gain
0
-20
Phase (Deg)
Vcc = 5V
RL = 8Ω
Tamb = 25 C
-220
-40
0.3
1
10
100
Frequency (kHz)
1000
10000
-240
Phase (Deg)
60
TS4890
Fig. 7 : Open Loop Frequency Response
0
0
Vcc = 2.2V
ZL = 8Ω + 560pF
Tamb = 25 C
Gain
-40
60
-60
-100
20
-120
-140
0
-160
40
Gain (dB)
Phase
-80
Phase
-100
-120
20
-140
0
-160
-180
-20
-180
-200
-20
-200
-220
1
10
100
1000
Frequency (kHz)
10000
-220
-240
-40
0.3
Fig. 9 : Open Loop Frequency Response
80
Phase
60
-80
100
-100
80
-120
60
Gain (dB)
Gain
-140
40
-160
20
-180
0
-40
0.3
1
1000
-140
40
-160
20
-180
10000
-200
Vcc = 3.3V
CL = 560pF
Tamb = 25 C
-40
0.3
1
-220
10
100
80
-100
80
Phase
-120
-140
40
-160
20
-180
0
-200
Vcc = 2.6V
CL = 560pF
Tamb = 25 C
100
10000
-240
1000
10000
-80
-100
Phase
-120
60
Gain (dB)
Gain
Phase (Deg)
Gain (dB)
60
Frequency (kHz)
1000
Fig. 12 : Open Loop Frequency Response
-80
10
100
Frequency (kHz)
100
1
-100
0
Fig. 11 : Open Loop Frequency Response
-40
0.3
-240
-120
Frequency (kHz)
-20
10000
Gain
-220
100
100
1000
Frequency (kHz)
Phase
-20
10
10
-80
-200
Vcc = 5V
CL = 560pF
Tamb = 25 C
-20
Phase (Deg)
100
1
Fig. 10 : Open Loop Frequency Response
Gain (dB)
-40
0.3
-40
-60
-80
Phase (Deg)
Gain (dB)
40
-20
Gain
-140
40
-160
20
-180
0
-200
Vcc = 2.2V
CL = 560pF
Tamb = 25 C
-220
-20
-240
-40
0.3
1
Phase (Deg)
Gain
60
80
-20
Phase (Deg)
Vcc = 2.2V
RL = 8Ω
Tamb = 25 C
Phase (Deg)
80
Fig. 8 : Open Loop Frequency Response
-220
10
100
1000
10000
-240
Frequency (kHz)
7/31
TS4890
Fig. 13 : Power Supply Rejection Ratio (PSRR)
vs Power supply
Fig. 14 : Power Supply Rejection Ratio (PSRR)
vs Feedback Capacitor
−30
−50
−60
−20
−30
PSRR (dB)
PSRR (dB)
−40
−10
Vripple = 200mVrms
Rfeed = 22kΩ
Input = floating
RL = 8Ω
Tamb = 25°C
Vcc = 5V to 2.2V
Cb = 1µF & 0.1µF
−40
−50
Vcc = 5 to 2.2V
Cb = 1µF & 0.1µF
Rfeed = 22kΩ
Vripple = 200mVrms
Input = floating
RL = 8Ω
Tamb = 25°C
Cfeed=0
Cfeed=150pF
Cfeed=330pF
−60
−70
−70
−80
10
100
1000
10000
Frequency (Hz)
Fig. 15 : Power Supply Rejection Ratio (PSRR)
vs Bypass Capacitor
−10
Cb=10µF
Vcc = 5 to 2.2V
Rfeed = 22k
Rin = 22k, Cin = 1µF
Rg = 100Ω, RL = 8Ω
Tamb = 25°C
−40
Cb=47µF
−50
1000
10000
Frequency (Hz)
Cin=1µF
100000
Vcc = 5 to 2.2V
Rfeed = 22k, Rin = 22k
Cb = 1µF
Rg = 100Ω , RL = 8Ω
Tamb = 25°C
Cin=330nF
−20
PSRR (dB)
Cb=1µF
−30
PSRR (dB)
100
Fig. 16 : Power Supply Rejection Ratio (PSRR)
vs Input Capacitor
−10
−20
Cfeed=680pF
−80
10
100000
Cin=220nF
−30
−40
−60
Cin=100nF
−50
−70
Cin=22nF
Cb=100µF
−80
10
100
1000
10000
−60
10
100000
100
Frequency (Hz)
Fig. 17 : Power Supply Rejection Ratio (PSRR)
vs Feedback Resistor
−40
Rfeed=110kΩ
Rfeed=47kΩ
−50
−60
Rfeed=22kΩ
−70
−80
10
1.2
1.0
Gv = 2 & 10
Cb = 1 F
F = 1kHz
BW < 125kHz
Tamb = 25 C
8Ω
6Ω
4Ω
0.8
16 Ω
0.6
0.4
0.2
32 Ω
Rfeed=10k Ω
100
1000
Frequency (Hz)
8/31
100000
1.4
Vcc = 5 to 2.2V
Cb = 1µF & 0.1µF
Vripple = 200mVrms
Input = floating
RL = 8Ω
Tamb = 25°C
Output power @ 1% THD + N (W)
PSRR (dB)
−30
10000
Fig. 18 : Pout @ THD + N = 1% vs Supply
Voltage vs RL
−10
−20
1000
Frequency (Hz)
10000
100000
0.0
2.5
3.0
3.5
4.0
Vcc (V)
4.5
5.0
TS4890
Fig. 20 : Power Dissipation vs Pout
1.4
2.0 Gv = 2 & 10
1.8 Cb = 1 F
F = 1kHz
1.6 BW < 125kHz
1.4 Tamb = 25 C
8Ω
4Ω
Power Dissipation (W)
Output power @ 10% THD + N (W)
Fig. 19 : Pout @ THD + N = 10% vs Supply
Voltage vs RL
6Ω
1.2
1.0
16 Ω
0.8
0.6
Vcc=5V
1.2 F=1kHz
THD+N<1%
RL=4Ω
1.0
0.8
0.6
RL=8Ω
0.4
0.4
0.0
2.5
0.2
32 Ω
0.2
3.0
3.5
4.0
4.5
RL=16Ω
0.0
0.0
5.0
0.2
0.4
Vcc (V)
Fig. 21 : Power Dissipation vs Pout
RL=4Ω
Power Dissipation (W)
Power Dissipation (W)
1.0
1.2
1.4
0.40
Vcc=3.3V
F=1kHz
0.5 THD+N<1%
0.4
0.3
0.2
RL=8Ω
Vcc=2.6V
0.35 F=1kHz
THD+N<1%
0.30
0.20
0.15
RL=8Ω
0.05
RL=16Ω
0.2
0.4
RL=4Ω
0.25
0.10
0.1
0.6
RL=16Ω
0.00
0.0
0.8
0.1
0.2
Output Power (W)
0.4
Fig. 24 : Power Derating Curves
0.40
SO8 on
demoboard
RL=4Ω
0.25
0.20
0.15
RL=8Ω
0.10
Power Dissipation (W)
1.2
Vcc=2.6V
0.35 F=1kHz
THD+N<1%
0.30
0.3
Output Power (W)
Fig. 23 : Power Dissipation vs Pout
Power Dissipation (W)
0.8
Fig. 22 : Power Dissipation vs Pout
0.6
0.0
0.0
0.6
Output Power (W)
1.0
MiniSO8 on
demoboard
0.8
0.6
0.4
MiniSO8
SO8
0.2
0.05
0.00
0.0
RL=16Ω
0.0
0.1
0.2
Output Power (W)
0.3
0
25
50
75
100
125
150
Ambiant Temperature (°C)
9/31
TS4890
Fig. 25 : THD + N vs Output Power
Fig. 26 : THD + N vs Output Power
10
Rl = 4 Ω
Vcc = 5V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
RL = 4Ω, Vcc = 5V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz, Tamb = 25 C
THD + N (%)
THD + N (%)
10
1
20kHz
20kHz
1
20Hz
20Hz, 1kHz
0.1
1E-3
0.01
0.1
Output Power (W)
1kHz
0.1
1E-3
1
Fig. 27 : THD + N vs Output Power
1
Fig. 28 : THD + N vs Output Power
10
10
RL = 4Ω, Vcc = 3.3V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
THD + N (%)
THD + N (%)
0.01
0.1
Output Power (W)
1
RL = 4 Ω, Vcc = 3.3V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
20kHz
1
20kHz
0.1
20Hz
1kHz
20Hz, 1kHz
0.1
1E-3
0.01
0.1
Output Power (W)
Fig. 29 : THD + N vs Output Power
1E-3
0.01
0.1
Output Power (W)
1
Fig. 30 : THD + N vs Output Power
10
RL = 4Ω, Vcc = 2.6V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
THD + N (%)
THD + N (%)
10
1
1
RL = 4Ω , Vcc = 2.6V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
1
20kHz
20kHz
20Hz
0.1
1kHz
20Hz, 1kHz
0.1
1E-3
10/31
0.01
0.1
Output Power (W)
1E-3
0.01
0.1
Output Power (W)
TS4890
Fig. 31 : THD + N vs Output Power
Fig. 32 : THD + N vs Output Power
10
10
RL = 4Ω , Vcc = 2.2V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
THD + N (%)
THD + N (%)
RL = 4Ω, Vcc = 2.2V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
1
20kHz
1
20kHz
20Hz
0.1
20Hz, 1kHz
0.1
1E-3
0.01
Output Power (W)
0.1
1E-3
Fig. 33 : THD + N vs Output Power
0.01
Output Power (W)
0.1
Fig. 34 : THD + N vs Output Power
10
10
RL = 8Ω
Vcc = 5V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
1
20Hz, 1kHz
THD + N (%)
THD + N (%)
1kHz
20kHz
RL = 8Ω
Vcc = 5V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
1
20Hz
20kHz
0.1
0.1
1kHz
1E-3
0.01
0.1
Output Power (W)
1E-3
1
1
Fig. 36 : THD + N vs Output Power
Fig. 35 : THD + N vs Output Power
10
10
RL = 8Ω, Vcc = 3.3V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
THD + N (%)
THD + N (%)
0.01
0.1
Output Power (W)
1
20Hz, 1kHz
RL = 8Ω, Vcc = 3.3V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
1
20Hz
20kHz
20kHz
0.1
0.1
1kHz
1E-3
0.01
0.1
Output Power (W)
1
1E-3
0.01
0.1
Output Power (W)
1
11/31
TS4890
Fig. 37 : THD + N vs Output Power
Fig. 38 : THD + N vs Output Power
10
RL = 8Ω, Vcc = 2.6V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
THD + N (%)
THD + N (%)
10
1
20Hz, 1kHz
1
20Hz
1kHz
0.1
1E-3
0.01
0.1
Output Power (W)
1E-3
Fig. 39 : THD + N vs Output Power
10
THD + N (%)
RL = 8Ω, Vcc = 2.2V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
1
1kHz
RL = 8Ω , Vcc = 2.2V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
1
20Hz
20kHz
20kHz
20Hz
0.1
1kHz
0.1
1E-3
0.01
0.1
1E-3
Output Power (W)
0.01
0.1
Output Power (W)
Fig. 41 : THD + N vs Output Power
Fig. 42 : THD + N vs Output Power
10
10
RL = 8Ω, Vcc = 5V, Gv = 10
Cb = 0.1 F, Cin = 1 F
BW < 125kHz, Tamb = 25 C
RL = 8Ω
Vcc = 5V
Gv = 2
Cb = 0.1 F, Cin = 1 F
BW < 125kHz
Tamb = 25 C
20kHz
20Hz
1kHz
THD + N (%)
THD + N (%)
0.01
0.1
Output Power (W)
Fig. 40 : THD + N vs Output Power
10
1
20kHz
20kHz
0.1
THD + N (%)
RL = 8Ω , Vcc = 2.6V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
20Hz
1
20kHz
1kHz
0.1
1E-3
12/31
0.1
0.01
0.1
Output Power (W)
1
1E-3
0.01
0.1
Output Power (W)
1
TS4890
Fig. 43 : THD + N vs Output Power
Fig. 44 : THD + N vs Output Power
10
RL = 8Ω, Vcc = 3.3V, Gv = 10
Cb = 0.1 F, Cin = 1 F
BW < 125kHz, Tamb = 25 C
RL = 8Ω, Vcc = 3.3V
Gv = 2
Cb = 0.1 F, Cin = 1 F
BW < 125kHz
Tamb = 25 C
THD + N (%)
THD + N (%)
10
1
20Hz
20kHz
1
20kHz
20Hz
1kHz
1kHz
0.1
0.1
1E-3
0.01
0.1
Output Power (W)
1
Fig. 45 : THD + N vs Output Power
1
10
RL = 8Ω, Vcc = 2.6V
Gv = 2
Cb = 0.1 F, Cin = 1 F
BW < 125kHz
Tamb = 25 C
RL = 8Ω, Vcc = 2.6V, Gv = 10
Cb = 0.1 F, Cin = 1 F
BW < 125kHz, Tamb = 25 C
1
20Hz
20kHz
1
20kHz
1kHz
20Hz
1kHz
0.1
0.1
1E-3
0.01
0.1
Output Power (W)
1E-3
Fig. 47 : THD + N vs Output Power
10
0.01
Output Power (W)
0.1
Fig. 48 : THD + N vs Output Power
10
RL = 8Ω, Vcc = 2.2V
Gv = 2
Cb = 0.1 F, Cin = 1 F
BW < 125kHz
Tamb = 25 C
RL = 8Ω, Vcc = 2.2V, Gv = 10
Cb = 0.1 F, Cin = 1 F
BW < 125kHz, Tamb = 25 C
THD + N (%)
THD + N (%)
0.01
0.1
Output Power (W)
Fig. 46 : THD + N vs Output Power
THD + N (%)
THD + N (%)
10
1E-3
1
20Hz
20kHz
1
20kHz
1kHz
1kHz
0.1
1E-3
20Hz
0.1
0.01
Output Power (W)
0.1
1E-3
0.01
0.1
Output Power (W)
13/31
TS4890
Fig. 49 : THD + N vs Output Power
Fig. 50 : THD + N vs Output Power
10
10
20kHz
RL = 16Ω , Vcc = 5V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
1
THD + N (%)
THD + N (%)
1
RL = 16Ω, Vcc = 5V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
20kHz
0.1
0.1
1kHz
20Hz, 1kHz
0.01
1E-3
0.01
0.1
Output Power (W)
1
Fig. 51 : THD + N vs Output Power
0.01
1E-3
0.01
0.1
Output Power (W)
10
THD + N (%)
RL = 16Ω, Vcc = 3.3V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
1
20kHz
0.1
1
RL = 16Ω
Vcc = 3.3V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
20kHz
0.1
1kHz
20Hz
20Hz, 1kHz
0.01
1E-3
0.01
Output Power (W)
0.01
1E-3
0.1
Fig. 53 : THD + N vs Output Power
THD + N (%)
THD + N (%)
0.1
10
RL = 16Ω
Vcc = 2.6V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
20kHz
0.1
1
RL = 16Ω
Vcc = 2.6V
Gv = 10
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
20Hz
20kHz
0.1
20Hz, 1kHz
0.01
1E-3
14/31
0.01
Output Power (W)
Fig. 54 : THD + N vs Output Power
10
1
1
Fig. 52 : THD + N vs Output Power
10
THD + N (%)
20Hz
0.01
Output Power (W)
1kHz
0.1
0.01
1E-3
0.01
Output Power (W)
0.1
TS4890
Fig. 55 : THD + N vs Output Power
Fig. 56 : THD + N vs Output Power
1
10
RL = 16Ω Vcc = 2.2V
Gv = 10, Cb = Cin = 1 F
BW < 125kHz, Tamb = 25 C
RL = 16Ω
Vcc = 2.2V
Gv = 2
Cb = Cin = 1 F
BW < 125kHz
Tamb = 25 C
THD + N (%)
THD + N (%)
10
20kHz
20Hz
0.1
1
20kHz
0.1
20Hz
1kHz
0.01
1E-3
1kHz
0.01
Output Power (W)
Fig. 57 : THD + N vs Frequency
1
Pout = 1.2W
100
1000
RL = 4 Ω, Vcc = 5V
Gv = 10
Cb = 1µF
BW < 125kHz
Tamb = 25°C
0.01
20
10000
Pout = 600mW
0.1
100
Frequency (Hz)
1000
Fig. 60 : THD + N vs Frequency
RL = 4Ω , Vcc = 3.3V
Gv = 2
Cb = 1µF
BW < 125kHz
Tamb = 25°C
RL = 4Ω, Vcc = 3.3V
Gv = 10
Cb = 1µF
BW < 125kHz
Tamb = 25°C
THD + N (%)
THD + N (%)
1
Pout = 540mW
Pout = 540mW
Pout = 270mW
0.1
20
100
1000
Frequency (Hz)
10000
Frequency (Hz)
Fig. 59 : THD + N vs Frequency
1
0.1
Pout = 1.2W
RL = 4Ω , Vcc = 5V
Gv = 2
Cb = 1µF
BW < 125kHz
Tamb = 25°C
Pout = 600mW
0.1
20
0.01
Output Power (W)
Fig. 58 : THD + N vs Frequency
THD + N (%)
THD + N (%)
1
0.01
1E-3
0.1
Pout = 270mW
10000
0.1
20
100
1000
10000
Frequency (Hz)
15/31
TS4890
Fig. 61 : THD + N vs Frequency
RL = 4Ω , Vcc = 2.6V
Gv = 2
Cb = 1µF
BW < 125kHz
Tamb = 25°C
RL = 4Ω, Vcc = 2.6V
Gv = 10
Cb = 1µF
BW < 125kHz
Tamb = 25°C
1
Pout = 240mW
THD + N (%)
THD + N (%)
1
Fig. 62 : THD + N vs Frequency
Pout = 240 & 120mW
Pout = 120mW
0.1
20
100
1000
0.1
20
10000
100
Frequency (Hz)
Fig. 63 : THD + N vs Frequency
10000
Fig. 64 : THD + N vs Frequency
RL = 4Ω , Vcc = 2.2V
Gv = 2
Cb = 1µF
BW < 125kHz
Tamb = 25°C
1
THD + N (%)
THD + N (%)
1
1000
Frequency (Hz)
Pout = 175mW
RL = 4Ω, Vcc = 2.2V
Gv = 10
Cb = 1µF
BW < 125kHz
Tamb = 25°C
Pout = 175mW
Pout = 88mW
Pout = 88mW
0.1
20
100
1000
0.1
20
10000
100
Frequency (Hz)
1000
10000
Frequency (Hz)
Fig. 65 : THD + N vs Frequency
Fig. 66 : THD + N vs Frequency
1
Cb = 0.1µF
Cb = 1µF
RL = 8Ω
Vcc = 5V
Gv = 2
Pout = 450mW
BW < 125kHz
Tamb = 25°C
THD + N (%)
THD + N (%)
1
RL = 8Ω
Vcc = 5V
Gv = 2
Pout = 900mW
BW < 125kHz
Tamb = 25°C
Cb = 0.1µF
Cb = 1µF
0.1
20
100
1000
Frequency (Hz)
16/31
10000
0.1
20
100
1000
Frequency (Hz)
10000
TS4890
Fig. 68 : THD + N vs Frequency
RL = 8Ω, Vcc = 5V
Gv = 10
Pout = 900mW
BW < 125kHz
Tamb = 25°C
THD + N (%)
1
Cb = 0.1µF
1
Cb = 0.1µF
Cb = 1µF
Cb = 1µF
0.1
20
0.1
100
1000
Frequency (Hz)
10000
20
100
10000
Fig. 70 : THD + N vs Frequency
1
1
Cb = 0.1µF
Cb = 1µF
RL = 8Ω , Vcc = 3.3V
Gv = 2
Pout = 200mW
BW < 125kHz
Tamb = 25°C
THD + N (%)
THD + N (%)
RL = 8Ω , Vcc = 3.3V
Gv = 2
Pout = 400mW
BW < 125kHz
Tamb = 25°C
0.1
Cb = 0.1µF
Cb = 1µF
0.1
100
1000
10000
20
100
Frequency (Hz)
10000
Fig. 72 : THD + N vs Frequency
Cb = 0.1µF
Cb = 1µF
RL = 8Ω, Vcc = 3.3V
Gv = 10
Pout = 200mW
BW < 125kHz
Tamb = 25°C
1
THD + N (%)
RL = 8 Ω, Vcc = 3.3V
Gv = 10
Pout = 400mW
BW < 125kHz
Tamb = 25°C
1
1000
Frequency (Hz)
Fig. 71 : THD + N vs Frequency
THD + N (%)
1000
Frequency (Hz)
Fig. 69 : THD + N vs Frequency
20
RL = 8Ω, Vcc = 5V
Gv = 10
Pout = 450mW
BW < 125kHz
Tamb = 25°C
THD + N (%)
Fig. 67 : THD + N vs Frequency
Cb = 0.1µF
Cb = 1µF
0.1
0.1
20
100
1000
Frequency (Hz)
10000
20
100
1000
10000
Frequency (Hz)
17/31
TS4890
Fig. 73 : THD + N vs Frequency
Fig. 74 : THD + N vs Frequency
1
1
Cb = 1µF
RL = 8 Ω, Vcc = 2.6V
Gv = 2
Pout = 110mW
BW < 125kHz
Tamb = 25°C
THD + N (%)
THD + N (%)
Cb = 0.1µF
RL = 8Ω , Vcc = 2.6V
Gv = 2
Pout = 220mW
BW < 125kHz
Tamb = 25°C
Cb = 0.1µF
Cb = 1µF
0.1
20
0.1
100
1000
10000
20
100
Frequency (Hz)
Fig. 75 : THD + N vs Frequency
Cb = 0.1µF
RL = 8Ω, Vcc = 2.6V
Gv = 10
Pout = 110mW
BW < 125kHz
Tamb = 25°C
1
Cb = 0.1µF
THD + N (%)
THD + N (%)
10000
Fig. 76 : THD + N vs Frequency
RL = 8Ω, Vcc = 2.6V
Gv = 10
Pout = 220mW
BW < 125kHz
Tamb = 25°C
1
1000
Frequency (Hz)
Cb = 1µF
Cb = 1µF
0.1
0.1
20
100
1000
10000
20
100
Frequency (Hz)
1000
10000
Frequency (Hz)
Fig. 77 : THD + N vs Frequency
Fig. 78 : THD + N vs Frequency
1
1
Cb = 1µF
RL = 8Ω , Vcc = 2.2V
Gv = 2
Pout = 75mW
BW < 125kHz
Tamb = 25°C
THD + N (%)
THD + N (%)
Cb = 0.1µF
RL = 8Ω , Vcc = 2.2V
Gv = 2
Pout = 150mW
BW < 125kHz
Tamb = 25°C
Cb = 0.1µF
Cb = 1µF
0.1
20
0.1
100
1000
Frequency (Hz)
18/31
10000
20
100
1000
Frequency (Hz)
10000
TS4890
Fig. 80 : THD + N vs Frequency
RL = 8Ω , Vcc = 2.2V
Gv = 10
Pout = 150mW
BW < 125kHz
Tamb = 25°C
THD + N (%)
1
Cb = 0.1µF
RL = 8Ω, Vcc = 2.2V
Gv = 10
Pout = 75mW
BW < 125kHz
Tamb = 25°C
1
Cb = 0.1µF
THD + N (%)
Fig. 79 : THD + N vs Frequency
Cb = 1µF
Cb = 1µF
0.1
0.1
20
100
1000
20
10000
100
10000
Fig. 82 : THD + N vs Frequency
Fig. 81 : THD + N vs Frequency
1
1
RL = 16Ω, Vcc = 5V
Gv = 10, Cb = 1µF
BW < 125kHz
Tamb = 25°C
THD + N (%)
RL = 16Ω , Vcc = 5V
Gv = 2, Cb = 1µF
BW < 125kHz
Tamb = 25°C
THD + N (%)
1000
Frequency (Hz)
Frequency (Hz)
Pout = 310mW
0.1
Pout = 620mW
0.1
Pout = 310mW
Pout = 620mW
0.01
20
100
1000
Frequency (Hz)
10000
0.01
20
1000
10000
Frequency (Hz)
Fig. 84 : THD + N vs Frequency
Fig. 83 : THD + N vs Frequency
1
1
THD + N (%)
RL = 16Ω, Vcc = 3.3V
Gv = 2, Cb = 1µF
BW < 125kHz
Tamb = 25°C
THD + N (%)
100
Pout = 270mW
0.1
RL = 16Ω , Vcc = 3.3V
Gv = 10
Cb = 1µF
BW < 125kHz
Tamb = 25°C
Pout = 270mW
0.1
Pout = 135mW
Pout = 135mW
0.01
20
100
1000
Frequency (Hz)
10000
20
100
1000
10000
Frequency (Hz)
19/31
TS4890
Fig. 86 : THD + N vs Frequency
Fig. 85 : THD + N vs Frequency
1
1
RL = 16Ω, Vcc = 2.6V
Gv = 2, Cb = 1µF
BW < 125kHz
Tamb = 25°C
Pout = 160mW
THD + N (%)
THD + N (%)
RL = 16Ω, Vcc = 2.6V
Gv = 10, Cb = 1µF
BW < 125kHz
Tamb = 25°C
0.1
Pout = 80mW
0.1
Pout = 80mW
0.01
20
100
1000
Frequency (Hz)
Pout = 160mW
0.01
20
10000
1000
10000
Frequency (Hz)
Fig. 88 : THD + N vs Frequency
Fig. 87 : THD + N vs Frequency
1
1
RL = 16Ω, Vcc = 2.2V
Gv = 10, Cb = 1µF
BW < 125kHz
Tamb = 25°C
THD + N (%)
RL = 16Ω, Vcc = 2.2V
Gv = 2, Cb = 1µF
BW < 125kHz
Tamb = 25°C
THD + N (%)
100
Pout = 50 & 100mW
0.1
Pout = 50mW
0.1
Pout = 100mW
0.01
20
100
1000
0.01
20
10000
100
Fig. 89 : Signal to Noise Ratio vs Power Supply
with Unweighted Filter (20Hz to 20kHz)
90
90
80
RL=4Ω
RL=8Ω
SNR (dB)
SNR (dB)
RL=16Ω
80
70
Gv = 2
Cb = Cin = 1µF
THD+N < 0.4%
Tamb = 25°C
60
2.5
3.0
3.5
Vcc (V)
20/31
10000
Fig. 90 :Signal to Noise Ratio Vs Power Supply
with Unweighted Filter (20Hz to 20kHz)
100
50
2.2
1000
Frequency (Hz)
Frequency (Hz)
4.0
4.5
5.0
RL=8Ω
70
RL=4Ω
RL=16Ω
Gv = 10
Cb = Cin = 1µF
THD+N < 0.7%
Tamb = 25°C
60
50
2.2
2.5
3.0
3.5
Vcc (V)
4.0
4.5
5.0
TS4890
Fig. 91 : Signal to Noise Ratio vs Power Supply
with Weighted Filter type A
Fig. 92 : Signal to Noise Ratio vs Power Supply
with Weighted Filter Type A
100
110
100
90
90
RL=4Ω
RL=16Ω
SNR (dB)
SNR (dB)
RL=8Ω
80
Gv = 2
Cb = Cin = 1µF
THD+N < 0.4%
Tamb = 25°C
70
60
2.2
2.5
3.0
3.5
Vcc (V)
4.0
4.5
5
6
-15
Icc (mA)
Gain (dB)
Cfeed = 680pF
-10
Cfeed = 2.2nF
-25
10
100
1000
Frequency (Hz)
5.0
Vstandby = Vcc
Tamb = 25°C
3
0
1
2
3
4
5
Vcc (V)
Fig. 96 : Current Consumption vs Standby
Voltage @ Vcc = 3.3V
7
6
6
5
5
4
4
Icc (mA)
Icc (mA)
4.5
4
0
10000
Fig. 95 : Current Consumption vs Standby
Voltage @ Vcc = 5V
3
3
2
2
1
0
0.0
4.0
1
Rin = Rfeed = 22kΩ
Tamb = 25 C
Cin = 82nF
3.5
Vcc (V)
2
Cin = 22nF
-20
3.0
5
Cfeed = 330pF
Cin = 470nF
2.5
Fig. 94 : Current Consumption vs Power
Supply Voltage (no load)
7
-5
Gv = 10
Cb = Cin = 1µF
THD+N < 0.7%
Tamb = 25°C
60
2.2
10
0
RL=4Ω
70
5.0
Fig. 93 : Frequency Response Gain vs Cin, &
Cfeed
RL=8Ω
RL=16Ω
80
Vcc = 5V
Tamb = 25°C
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Vstandby (V)
4.0
4.5
5.0
1
0
0.0
Vcc = 3.3V
Tamb = 25°C
0.5
1.0
1.5
2.0
2.5
3.0
Vstandby (V)
21/31
TS4890
Fig. 97 : Current Consumption vs Standby
Voltage @ Vcc = 2.6V
Fig. 98 : Current Consumption vs Standby
Voltage @ Vcc = 2.2V
6
5
5
4
Icc (mA)
Icc (mA)
4
3
3
2
2
1
1
Vcc = 2.6V
Tamb = 25°C
0
0.0
0.5
1.0
1.5
Vstandby (V)
2.0
Vcc = 2.2V
Tamb = 25 C
0
0.0
2.5
2.0
1.0
Tamb = 25 C
0.9
0.8
Vout1 & Vout2
Clipping Voltage Low side (V)
Vout1 & Vout2
Clipping Voltage High side (V)
1.5
Fig. 100 :Clipping Voltage vs Power Supply
Voltage and Load Resistor
1.0
0.7
0.6
0.5
RL = 4Ω
RL = 8Ω
0.4
0.3
0.2
0.1
0.0
2.2
RL = 16Ω
2.5
3.0
3.5
4.0
Power supply Voltage (V)
22/31
1.0
Vstandby (V)
Fig. 99 : Clipping Voltage vs Power Supply
Voltage and Load Resistor
0.9
0.5
4.5
5.0
Tamb = 25 C
0.8
0.7
0.6
RL = 4Ω
0.5
RL = 8Ω
0.4
0.3
0.2
0.1
0.0
2.2
RL = 16Ω
2.5
3.0
3.5
4.0
Power supply Voltage (V)
4.5
5.0
TS4890
APPLICATION INFORMATION
Fig. 101 : Demoboard Schematic
C1
R2
C2
R1
S1
Vcc
Vcc
Vcc
S2
GND
C6 +
100µ
R3
6
C3
C5
R4
C4
Pos input
S6
Vcc
Neg. input
P1
C7
100n
4
R5
VinVin+
3
-
Vout1 5
C9
+
470µ
+
S5
Positive Input mode
P2
Vcc
2
Bypass
1
Standby
Av=-1
+
R8
10k
Vout2
8
C10
+
470µ
Bias
GND
S8
Standby
GND
S4
GND
S7
R6
-
R7
1.5k
OUT1
S3
D1
PW ON
TS4890
7
+
C11
+
C12
1u
C8
Fig. 102 : SO8 & MiniSO8 Demoboard Components Side
23/31
TS4890
Fig. 103 : SO8 & MiniSO8 Demoboard Top
Solder Layer
The output power is :
Pout =
(2 VoutRMS )2
(W)
RL
For the same power supply voltage, the output
power in BTL configuration is four times higher
than the output power in single ended
configuration.
■ Gain In Typical Application Schematic
(cf. page 1)
In flat region (no effect of Cin), the output voltage
of the first stage is :
Rfeed
Vout1 = −Vin
(V)
Rin
For the second stage : Vout2 = -Vout1 (V)
Fig. 104 : SO8 & MiniSO8 Demoboard Bottom
Solder Layer
The differential output voltage is
Rfeed
Vout 2 − Vout1 = 2 Vin
(V)
Rin
The differential gain named gain (Gv) for more
convenient usage is :
Gv =
Vout 2 − Vout1
Rfeed
=2
Vin
Rin
Remark : Vout2 is in phase with Vin and Vout1 is
180 phased with Vin. It means that the positive
terminal of the loudspeaker should be connected
to Vout2 and the negative to Vout1.
■ Low and high frequency response
■ BTL Configuration Principle
The TS4890 is a monolithic power amplifier with a
BTL output type. BTL (Bridge Tied Load) means
that each end of the load are connected to two
single ended output amplifiers. Thus, we have :
Single ended output 1 = Vout1 = Vout (V)
Single ended output 2 = Vout2 = -Vout (V)
And Vout1 - Vout2 = 2Vout (V)
24/31
In low frequency region, the effect of Cin starts.
Cin with Rin forms a high pass filter with a -3dB cut
off frequency .
FCL =
1
2πRinCin
(Hz)
In high frequency region, you can limit the
bandwidth by adding a capacitor (Cfeed) in
parallel on Rfeed. Its form a low pass filter with a
-3dB cut off frequency .
1
FCH =
(Hz)
2π Rfeed Cfeed
TS4890
■ Power dissipation and efficiency
Hypothesis :
• Voltage and current in the load are sinusoidal
(Vout and Iout)
• Supply voltage is a pure DC source (Vcc)
Regarding the load we have :
VOUT = VPEAK sin ωt (V)
VOUT
( A)
RL
and
2
POUT
V
= PEAK (W)
2 RL
Then, the average current delivered by the supply
voltage is
V
Icc AVG = 2 PEAK (A)
π RL
The power delivered by the supply voltage is
Psupply = Vcc IccAVG (W)
Then, the power dissipated by the amplifier is
Pdiss = Psupply - Pout (W)
Pdiss =
2 2 Vcc
π RL
POUT − POUT (W )
and the maximum value is obtained when
∂Pdiss
=0
∂POUT
and its value is
Pdiss max =
2 Vcc 2
π2RL
π
= 78.5%
4
■ Decoupling of the circuit
Two capacitors are needed to bypass properly the
TS4890. A power supply bypass capacitor Cs and
a bias voltage bypass capacitor Cb.
Cs has especially an influence on the THD+N in
high frequency (above 7kHz) and indirectly on the
power supply disturbances.
With 100µF, you can expect similar THD+N
performances like shown in the datasheet.
and
IOUT =
The maximum theoretical value is reached when
Vpeak = Vcc, so
(W)
If Cs is lower than 100µF, in high frequency
increase THD+N and disturbances on the power
supply rail are less filtered.
To the contrary, if Cs is higher than 100µF, those
disturbances on the power supply rail are more
filtered.
Cb has an influence on THD+N in lower frequency,
but its function is critical on the final result of PSRR
with input grounded in lower frequency.
If Cb is lower than 1µF, THD+N increase in lower
frequency (see THD+N vs frequency curves) and
the PSRR worsens up
If Cb is higher than 1µF, the benefit on THD+N in
lower frequency is small but the benefit on PSRR
is substantial (see PSRR vs. Cb curves).
Note that Cin has a non-negligible effect on PSRR
in lower frequency. Lower is its value, higher is the
PSRR (see fig. 13).
■ Pop and Click performance
In order to have the best performances with the
pop and click circuitry, the formula below must be
follow :
τin ≤ τb
Remark : This maximum value is only depending
on power supply voltage and load values.
With
The efficiency is the ratio between the output
power and the power supply
and
POUT
π VPEAK
η=
=
P sup ply
4 Vcc
τin = (Rin + Rfeed ) × Cin (s)
τb = 50kΩ × Cb (s)
25/31
TS4890
■ Power amplifier design examples
Given :
• Load impedance : 8Ω
• Output power @ 1% THD+N : 0.5W
• Input impedance : 10kΩ min.
• Input voltage peak to peak : 1Vpp
• Bandwidth frequency : 20Hz to 20kHz (0, -3dB)
• THD+N in 20Hz to 20kHz < 0.5% @Pout=0.45W
• Ambient temperature max = 50°C
• SO8 package
First of all, we must calculate the minimum power
supply voltage to obtain 0.5W into 8Ω. See curves
in fig. 15, we can read 3.5V. Thus, the power
supply voltage value min. will be 3.5V.
Following the
equation :
maximum
Pdiss max =
power
2 Vcc2
π2RL
dissipation
(W)
with 3.5V we have Pdissmax=0.31W.
Refer to power derating curves (fig. 24), with
0.31W the maximum ambient temperature will be
100°C. This last value could be higher if you follow
the example layout shows on the demoboard
(better dissipation).
The gain of the amplifier in flat region will be :
GV =
VOUTPP 2 2RLPOUT
=
= 5.65
VINPP
VINPP
We have Rin > 10kΩ. Let’s take Rin = 10kΩ, then
Rfeed = 28.25kΩ. We could use for Rfeed = 30kΩ
in normalized value and the gain will be Gv = 6.
The first amplifier has a gain of
Rfeed
=3
Rin
and the theoretical value of the -3dB cut of higher
frequency is 2MHz/3 = 660kHz.
We can keep this value or limiting the bandwidth
by adding a capacitor Cfeed, in parallel on Rfeed.
Then
CFEED =
1
= 795nF
2π Rin FCL
So, we could use for Cin a 1µF capacitor value that
gives 16Hz.
In Higher frequency we want 20kHz (-3dB cut off
frequency). The Gain Bandwidth Product of the
TS4890 is 2MHz typical and doesn’t change when
the amplifier delivers power into the load.
26/31
2π RFEED FCH
= 265pF
So, we could use for Cfeed a 220pF capacitor
value that gives 24kHz.
Now, we can choose the value of Cb with the
constraint THD+N in 20Hz to 20kHz < 0.5% @
Pout=0.45W. If you refer to the closest THD+N vs
frequency measurement : fig. 71 (Vcc=3.3V,
Gv=10), with Cb = 1µF, the THD+N vs frequency
is always below 0.4%. As the behaviour is the
same with Vcc = 5V (fig. 67), Vcc = 2.6V (fig. 67).
As the gain for these measurements is higher
(worst case), we can consider with Cb = 1µF, Vcc
= 3.5V and Gv = 6, that the THD+N in 20Hz to
20kHz range with Pout = 0.45W will be lower than
0.4%.
In the following tables, you could find three
another examples with values required for the
demoboard.
Remark : components with (*) marking are
optional.
Application n°1 : 20Hz to 20kHz bandwidth and
6dB gain BTL power amplifier.
Components :
In lower frequency we want 20 Hz (-3dB cut off
frequency). Then
CIN =
1
Designator
Part Type
R1
22k / 0.125W
R4
22k / 0.125W
R6
Short Cicuit
R7*
(Vcc-Vf_led)/If_led
R8
10k / 0.125W
C5
470nF
C6
100µF
TS4890
Designator
Part Type
C7
100nF
C9
Short Circuit
C10
Short Circuit
C12
1µF
S1, S2, S6, S7
2mm insulated Plug
10.16mm pitch
S8
3 pts connector 2.54mm
pitch
P1
PCB Phono Jack
D1*
Led 3mm
U1
TS4890ID or TS4890IS
Application n°3 : 50Hz to 10kHz bandwidth and
10dB gain BTL power amplifier.
Components :
Designator
Application n°2 : 20Hz to 20kHz bandwidth and
20dB gain BTL power amplifier.
Part Type
R1
33k / 0.125W
R2
Short Circuit
R4
22k / 0.125W
R6
Short Cicuit
R7*
(Vcc-Vf_led)/If_led
R8
10k / 0.125W
C2
470pF
C5
150nF
C6
100µF
C7
100nF
C9
Short Circuit
C10
Short Circuit
C12
1µF
S1, S2, S6, S7
2mm insulated Plug
10.16mm pitch
S8
3 pts connector 2.54mm
pitch
P1
PCB Phono Jack
D1*
Led 3mm
U1
TS4890ID or TS4890IS
Components :
Designator
Part Type
R1
110k / 0.125W
R4
22k / 0.125W
R6
Short Cicuit
R7*
(Vcc-Vf_led)/If_led
R8
10k / 0.125W
C5
470nF
C6
100µF
C7
100nF
C9
Short Circuit
C10
Short Circuit
C12
1µF
S1, S2, S6, S7
2mm insulated Plug
10.16mm pitch
S8
3 pts connector 2.54mm
pitch
P1
PCB Phono Jack
D1*
Led 3mm
U1
TS4890ID or TS4890IS
Application n°4 : Differential inputs BTL power
amplifier.
In this configuration, we need to place these
components : R1, R4, R5, R6, R7, C4, C5, C12.
We have also : R4 = R5, R1 = R6, C4 = C5.
The gain of the amplifier is :
GVDIFF = 2
R1
(Pos. Input − Neg. Input )
R4
For a 20Hz to 20kHz bandwidth and 6dB gain BTL
power amplifier you could follow the bill of material
below.
27/31
TS4890
Components :
Designator
Part Type
In reality we want a value about -70dB. So, we
need a gain of 34dB !
Now, on fig. 15 we can see the effect of Cb on the
PSRR (input grounded) vs. frequency. With
Cb=100µF, we can reach the -70dB value.
R1
22k / 0.125W
R4
22k / 0.125W
R5
22k / 0.125W
R6
22k / 0.125W
R7*
(Vcc-Vf_led)/If_led
R8
10k / 0.125W
The process to obtain the final curve (Cb=100µF,
Cin=100nF, Rin=Rfeed=22kΩ) is a simple transfer
point by point on each frequency of the curve on
fig. 16 to the curve on fig. 15.
The measurement result is shown on the next
figure.
C4
470nF
Fig. 105 : PSRR changes with Cb
C5
470nF
C6
100µF
C7
100nF
−40
Short Circuit
C10
Short Circuit
C12
1µF
−60
D1*
Led 3mm
−70
S1, S2, S6, S7
2mm insulated Plug
10.16mm pitch
S8
3 pts connector 2.54mm
pitch
P1, P2
PCB Phono Jack
U1
TS4890ID or TS4890IS
(page 8)
We have finished a design and we have chosen for
the components :
• Rin=Rfeed=22kΩ
• Cin=100nF
• Cb=1µF
Now, on fig. 16, we can see the PSRR (input
grounded) vs frequency curves. At 217Hz, we
have a PSRR value of -36dB.
28/31
PSRR (dB)
C9
■ Note on how to use the PSRR curves
Vcc = 5 to 2.2V
Rfeed = 22k, Rin = 22k
Rg = 100Ω , RL = 8Ω
Tamb = 25°C
−30
Cin=100nF
Cb=1µF
−50
10
Cin=100nF
Cb=100µF
100
1000
Frequency (Hz)
10000
100000
TS4890
■ Note on PSRR measurement
■ Principle of operation
What is the PSRR ?
• We fixed the DC voltage supply (Vcc)
• We fixed the AC sinusoidal ripple voltage
(Vripple)
• No bypass capacitor Cs is used
The PSRR is the Power Supply Rejection Ratio.
It’s a kind of SVR in a determined frequency range.
The PSRR of a device, is the ratio between a
power supply disturbance and the result on the
output. We can say that the PSRR is the ability of
a device to minimize the impact of power supply
disturbances to the output.
The PSRR value for each frequency is :
 Rms (Vripple ) 
PSRR(dB) = 20 × Log10 

 Rms (Vs + − Vs − ) 
Remark : The measure of the Rms voltage is not a
Rms selective measure but a full range (2 Hz to
125 kHz) Rms measure. It means that we
measure the effective Rms signal + the noise.
How we measure the PSRR ?
Fig. 106 : PSRR measurement schematic
Rfeed
6
Vcc
Vripple
Vcc
4
Rin
3
VinVin+
-
Vout1 5
Vs-
+
Cin
RL
Bypass
1
Standby
Av=-1
+
Cb
Vout2
8
Vs+
Bias
GND
Rg
100 Ohms
2
TS4890
7
29/31
TS4890
PACKAGE MECHANICAL DATA
8 PINS - PLASTIC MICROPACKAGE (SO)
s
b1
b
a1
A
a2
C
c1
a3
L
E
e3
D
M
5
1
4
F
8
Millimeters
Inches
Dim.
Min.
A
a1
a2
a3
b
b1
C
c1
D
E
e
e3
F
L
M
S
30/31
Typ.
Max.
Min.
Typ.
Max.
0.65
1.75
0.25
1.65
0.85
0.026
0.069
0.010
0.065
0.033
0.35
0.19
0.25
0.48
0.25
0.5
0.014
0.007
0.010
0.019
0.010
0.020
4.8
5.8
5.0
6.2
0.189
0.228
0.197
0.244
0.1
0.004
45° (typ.)
1.27
3.81
3.8
0.4
0.050
0.150
4.0
1.27
0.6
0.150
0.016
8° (max.)
0.157
0.050
0.024
TS4890
PACKAGE MECHANICAL DATA
8 PINS - PLASTIC MICROPACKAGE (miniSO)
k
0,25mm
.010inch
GAGEPLANE
C
SEATING
PLANE
E1
L1
L
c
A
E
A2
A1
4
8
1
e
C
ccc
b
D
5
PIN1IDENTIFICA TION
Dim.
A
A1
A2
b
c
D
E
E1
e
L
L1
k
aaa
Millimeters
Min.
Typ.
0.050
0.780
0.250
0.130
2.900
4.750
2.900
0.100
0.860
0.330
0.180
3.000
4.900
3.000
0.650
0.550
0.950
3d
0.400
0d
Inches
Max.
Min.
Typ.
1.100
0.150
0.940
0.400
0.230
3.100
5.050
3.100
0.002
0.031
0.010
0.005
0.114
0.187
0.114
0.700
0.016
6d
0.100
0d
0.004
0.034
0.013
0.007
0.118
0.193
0.118
0.026
0.022
0.037
3d
Max.
0.043
0.006
0.037
0.016
0.009
0.122
0.199
0.122
0.028
6d
0.004
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31/31