BL6311

BL6311
3 Watt Mono Filter-Free Class-D Audio Power Amplifier
Features
Efficiency With an 8-Ω Speaker:
88% at 400 mW
80% at 100 mW
2.6mA Quiescent Current
0.4µA Shutdown Current
Optimized PWM Output Stage Eliminates LC Output Filter
Internally Generated 250-kHz Switching Frequency Eliminates Capacitor and
Resistor
Improved PSRR (−75 dB) and Wide Supply Voltage (2.5 V to 5.5 V) Eliminates
Need for a Voltage Regulator
Fully Differential Design Reduces RF Rectification and Eliminates Bypass
Capacitor
Improved CMRR Eliminates Two Input Coupling Capacitors
Available in space-saving package: 9-bump WLCSP
General Description
The BL6311 is a 3-W high efficiency filter-free class-D audio power amplifier in
a wafer chip scale package (WCSP) that requires only three external components.
Features like 88% efficiency, −75dB PSRR, and improved RF-rectification
immunity make the BL6311 ideal for cellular handsets. In cellular handsets, the
earpiece, speaker phone, and melody ringer can each be driven by the BL6311.
Applications
Mobile phone、PDA
MP3/4、PMP
Portable electronic devices
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- Page 1 of 1 -
Ver1.3
BL6311
Pin Diagrams
1
2
3
A
IN+
GND
VO-
B
VDD
PVDD
PGND
C
IN-
SDB
VO+
top view
Pin Description
Pin #
A1
A2
A3
B1
B2
B3
C1
C2
C3
Name
IN+
GND
VOVDD
PVDD
PGND
INSDB
VO+
Description
Positive differential input
Power Ground
Negative BTL output
Power Supply
Power Supply
Power Ground
Negative differential input
Shutdown terminal (low active)
Positive BTL output
Function Block Diagram
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- Page 2 of 2 -
Ver1.3
BL6311
Av1 = 150k/Ri
(B1)
VDD
150k
(B2)
PVDD
(C1)
IN-
(A3)
Vo-
PWM Modulator and
Power Driver
Amp1
(A1)
IN+
(C3)
Vo+
Av2 = 2 V/V
(B3)
PGND
150k
(C2)
SDB
ShutDown
Control
300k
Start up &
Protection
Bias &
Reference
OSC &
RAMP
Notes: Total Voltage Gain = Av1 × Av 2 = 2 ×
(A2)
GND
OC
Detect
150k
RI
Figure 1. Function Block Diagram
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- Page 3 of 3 -
Ver1.3
BL6311
Application Circuit
VDD
Ri
Vi-
+
Differential
Input
Vi+
+
)
p
o
Lo
TL
B
&d
e
Ms
Wo
Pl
C
(
To Battery
Cs
Vo+
Vo-
Ri
GND
Bias &
ShutDown
SDB
OSC &
RAMP
Figure 2. BL6311 Application Schematic With Differential Input
VDD
Ci
Ri
Vi-
+
Differential
Input
Vi+
Ci
+
)
p
Lo
o
T
BL
&d
Me
s
W
Po
l
C
(
To Battery
Cs
Vo+
Vo-
Ri
GND
Bias &
ShutDown
SDB
OSC &
RAMP
Figure 3. BL6311 Application Schematic With Differential Input and Input Capacitors
VDD
Ci
Single-ended
Input
Ri
Vi-
+
Vi+
+
)
p
Lo
o
T
BL
&d
Me
s
W
Po
l
C
(
To Battery
Cs
Vo+
Vo-
Ri
Ci
GND
SDB
Bias &
ShutDown
OSC &
RAMP
Figure 4. BL6311 Application Schematic With Single-Ended Input
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- Page 4 of 4 -
Ver1.3
BL6311
Electrical Characteristics
The following specifications apply for the circuit shown in Figure 5.
TA = 25℃, unless otherwise specified.
Symb
Spec
Units
Parameter
Conditions
ol
Min. Typ. Max.
ISD
Shutdown Current
IQ
Quiescent Current
VOS
Output Offset Voltage
PSRR
Power Supply Rejection Ratio
CMRR Common Mode Rejection Ratio
FSW
AV
RSDB
ZI
TWU
rDS(on)
Modulation frequency
Voltage gain
VIN=0V, VSDB=0V, No Load
0.4
VDD = 2.5V, VIN = 0V, No Load
2.0
VDD = 3.6V, VIN = 0V, No Load
2.6
VDD = 5.5V, VIN = 0V, No Load
VIN = 0V, AV = 2V/V,
VDD = 2.5V to 5.5V
3.0
8
2
25
VDD = 2.5V to 5.5V
VDD = 2.5V to 5.5V,
VIC = VDD/2 to 0.5V,
VIC = VDD/2 to VDD - 0.8V
VDD = 2.5V to 5.5V
-75
dB
-68
dB
VDD = 2.5V to 5.5V
Resistance from SDB to GND
Input impedance
Wake-up time from shutdown
uA
mA
mV
200
250
300
kHz
285k
RI
300k
RI
315k
RI
V/V
158
kΩ
kΩ
mS
142
VDD = 3.6V
VDD = 2.5V
Drain-Source resistance (on-state) VDD = 3.6V
VDD = 5.5V
2
300
150
1
700
500
400
mΩ
Operating Characteristics
VDD = 5V, RI = 150kΩ, TA = 25℃, unless otherwise specified.
Symb
Spec
Parameter
Conditions
Units
ol
Min. Typ. Max.
PO
THD+N
SNR
Output Power
THD+N=10%, f=1KHz, RL = 4Ω
THD+N=1%, f=1KHz, RL = 4Ω
THD+N=10%, f=1KHz, RL = 8Ω
THD+N=1%, f=1KHz, RL = 8Ω
Total Harmonic
Po=1.0Wrms, f=1kHz, RL = 8Ω
Distortion + Noise
Signal-to-Noise ratio VDD=5V, Po=1.0Wrms, RL = 8Ω
3.0
2.4
1.7
1.4
W
0.19
%
97
dB
VDD = 3.6V, RI = 150kΩ, TA = 25℃, unless otherwise specified.
Spec
Symb
Parameter
Conditions
Units
ol
Min. Typ. Max.
PO
THD+N
Output Power
Total Harmonic
Distortion + Noise
Supply ripple
rejection ratio
THD+N=10%, f=1KHz, RL = 4Ω
THD+N=1%, f=1KHz, RL = 4Ω
THD+N=10%, f=1KHz, RL = 8Ω
THD+N=1%, f=1KHz, RL = 8Ω
1.5
1.2
0.9
0.7
W
Po=0.5Wrms, f=1kHz, RL = 8Ω
0.19
%
-68
dB
48
36
uVRMS
-70
dB
VDD = 3.6V, input ac-grounded with CI = 2uF
f=217Hz, V(Ripple)=200mVPP
V = 3.6V, input ac-grounded No weighting
Vn
Output voltage noise DD
with CI = 2uF, f=20~20kHz
A weighting
Common Mode
CMRR
VDD = 3.6V, VIC = 1 VPP, f=217Hz
Rejection Ratio
KSVR
VDD = 2.5V, RI = 150kΩ, TA = 25℃, unless otherwise specified.
Parameter
Conditions
Spec
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- Page 5 of 5 -
Units
Ver1.3
BL6311
Symb
ol
Symb
ol
THD+N
Parameter
Conditions
Spec
THD+N=10%, f=1KHz, RL = 4Ω
THD+N=1%, f=1KHz, RL = 4Ω
THD+N=10%, f=1KHz, RL = 8Ω
THD+N=1%, f=1KHz, RL = 8Ω
Total Harmonic
Distortion + Noise
Min.
Units
0.7
Typ.
Max.
0.55
0.4
0.3
Po=0.2Wrms, f=1kHz, RL = 8Ω
0.19
%
Test Circuit
Ci
Ri
IN+
Signal input
from
measurement
2uF
VO+
150K
Vin
BL6311
Ci
30KHz
LPF
RL
Ri
IN2uF
Output
to
measurement
VO
VO-
150K
Shutdown
signal
SDB
VDD
GND
CS
1uF
Power +
Supply
-
Figure 5. BL6311 test set up circuit
VO+
100
47nF
VO
VO-
100
47nF
30kHz LPF
Figure 6. 30-kHz LPF for BL6311 test
Notes: 1>. CS should be placed as close as possible to VDD/GND pad of the
device
2>. Ci should be shorted for any Common-Mode input voltage measurement
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- Page 6 of 6 -
Ver1.3
BL6311
3>. A 33uH inductor should be used in series with RL for efficiency
measurement
4>. The 30 kHz LPF (shown in figure 5) is required even if the analyzer has
an internal LPF
Component Recommended
Due to the weak noise immunity of the single-ended input application, the
differential input application should be used whenever possible. The typical
component values are listed in the table:
RI
CI
CS
150 k
3.3 nF
1 uF
(1) CI should have a tolerance of ±10% or better to reduce impedance
mismatch.
(2) Use 1% tolerance resistors or better to keep the performance optimized,
and place the RI close to the device to limit noise injection on the highimpedance nodes.
Input Resistors (RI) & Capacitors (CI)
The input resistors (RI) set the total voltage gain of the amplifier according to Eq1
Gain =
2 × 150kΩ
RI
V 
 
V 
Eq1
The input resistor matching directly affects the CMRR, PSRR, and the second
harmonic distortion cancellation.
If a differential signal source is used, and the signal is biased from 0.5V ~ VDD0.8V (shown in Figure2), the input capacitor (CI) is not required.
If the input signal is not biased within the recommended common-mode input
range in differential input application (shown in Figure3), or in a single-ended input
application (shown in Figure4), the input coupling capacitors are required.
If the input coupling capacitors are used, the RI and CI form a high-pass filter
(HPF). The corner frequency (fC) of the HPF can be calculated by Eq2
fC =
1
2π ⋅ RI ⋅ C I
(Hz )
Eq 2
Decoupling Capacitor (CS)
A good low equivalent-series-resistance (ESR) ceramic capacitor (CS), used as
power supply decoupling capacitor (CS), is required for high power supply rejection
(PSRR), high efficiency and low total harmonic distortion (THD). Typically CS is
1µF, placed as close as possible to the device VDD pin.
Typical Performance Characteristics
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- Page 7 of 7 -
Ver1.3
BL6311
Audio Precision
04/23/08 14:58:01
20
10
5
2
%
1
0.5
0.2
0.1
6m
10m
20m
50m
100m
200m
500m
1
2
3
W
Sweep
Trace
Color
Line Style
Thick
Data
1
2
3
4
1
1
1
1
Cyan
Green
Yellow
Red
Solid
Solid
Solid
Solid
1
1
1
1
Analyzer.THD+N
Analyzer.THD+N
Analyzer.THD+N
Analyzer.THD+N
Ratio
Ratio
Ratio
Ratio
B
B
B
B
Axis
Com m ent
Left
Left
Left
Left
2.5v
3v
3.6v
5v
Figure7 THDN vs PO (RL=4ohm, f=1kHz, Gain=2)
Audio Precision
20
10
5
%
2
1
0.5
0.2
0.1
5m
10m
20m
50m
100m
200m
500m
1
W
Sweep
Trace
Color
Line Style
Thick
Data
Axis
Comment
1
2
3
4
1
1
1
1
Magenta
Red
Yellow
Green
Solid
Solid
Solid
Solid
1
1
1
1
.Analyzer.THD+N Ratio B
.Analyzer.THD+N Ratio B
.Analyzer.THD+N Ratio B
.Analyzer.THD+N Ratio B
Left
Left
Left
Left
2.5V
3V
3.6V
5V
Figure8 THDN vs PO (RL=8ohm, f=1kHz, Gain=2)
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- Page 8 of 8 -
Ver1.3
BL6311
Audio Precision
100
10
1
%
0.1
0.01
0.001
0.0001
20
50
100
200
500
1k
2k
5k
10k
20k
Hz
Sweep Trace Color
1
2
3
1
1
1
Line Style Thick Data
Green Solid
Cyan Solid
Yellow Solid
1
1
1
Axis Comment
Analyzer.THD+N Ratio B Left
Analyzer.THD+N Ratio B Left
Analyzer.THD+N Ratio B Left
Po=25mW
Po=250mW
Po=1w
Figure9 THDN vs Frequency (VDD=5V RL=8ohm Gain=2 CI=2uF)
Audio Precision
10
1
%
0.1
0.01
20
50
100
200
500
1k
2k
5k
10k
20k
Hz
Sweep
Trace
Color
Line Style
Thick
Data
Axis
1
2
3
1
1
1
Green
Cyan
Yellow
Solid
Solid
Solid
1
1
1
Analyzer.THD+N Ratio B
Analyzer.THD+N Ratio B
Analyzer.THD+N Ratio B
Left
Left
Left
Comment
Figure10 THDN vs Frequency (VDD=3.6V RL=8ohm Gain=2 CI=2uF)
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- Page 9 of 9 -
Ver1.3
BL6311
Audio Precision
10
1
%
0.1
0.01
20
50
100
200
500
1k
2k
5k
10k
20k
Hz
Sweep Trace Color
1
2
3
1
1
1
Line Style Thick Data
Green Solid
Cyan
Solid
Yellow Solid
1
1
1
Axis
Analyzer.THD+N Ratio B Left
Analyzer.THD+N Ratio B Left
Analyzer.THD+N Ratio B Left
Comment
Po=15mW
Po=75mW
po=200mW
Figure11 THDN vs Frequency (VDD=2.5V RL=8ohm Gain=2 CI=2uF)
Audio Precision
-40
-60
d
B
-80
-100
-120
20
50
100
200
500
1k
2k
5k
10k
20k
Hz
Sweep Trace Color
1
2
3
1
1
1
Line Style Thick Data
Blue
Solid
Green Solid
Red
Solid
1
1
1
Axis
Analyzer.Crosstalk B Left
Analyzer.Crosstalk B Left
Analyzer.Crosstalk B Left
Comment
5V
3.6V
2.5V
Figure12 PSRR vs Frequency (RL=4ohm, Input ac-grounded)
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- Page 10 of 10 -
Ver1.3
BL6311
Audio Precision
psrr
04/23/08 14:02:31
-40
-60
d
B
-80
-100
-120
20
50
100
200
500
1k
2k
5k
10k
20k
10k
20k
Hz
Sweep Trace Color
1
2
3
1
1
1
Line Style Thick Data
Cyan Solid
Green Solid
Yellow Solid
1
1
1
Axis Comment
Analyzer.Crosstalk B Left 5v
Analyzer.Crosstalk B Left 3.6v
Analyzer.Crosstalk B Left 2.5v
Figure13 PSRR vs Frequency (RL=8ohm, Input ac-grounded)
Audio Precision
-40
-60
d
B
-80
-100
-120
20
50
100
200
500
1k
2k
5k
Hz
Sweep Trace Color
1
2
3
1
1
1
Line Style Thick Data
Blue
Solid
Green Solid
Red
Solid
1
1
1
Axis
Analyzer.Crosstalk B Left
Analyzer.Crosstalk B Left
Analyzer.Crosstalk B Left
Comment
5V
3.6V
2.5V
Figure14 PSRR vs Frequency (RL=8ohm, Input floating)
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- Page 11 of 11 -
Ver1.3
BL6311
Efficiency vs Po
1
0.9
Efficiency %
0.8
0.7
0.6
0.5
0.4
0.3
0.2
Vdd=5V
Vdd=2.5
0.1
0
0
0.02 0.05 0.1 0.15 0.2 0.25 0.4 0.5 0.6 0.8
1
Po
1.2
Figure15 GSM Power Supply Rejection vs Time
(RL=8Ω
Ω+33uH)
Supply Current vs Po
0.3
Vdd=5V
Vdd=2.5V
0.25
IDD (A)
0.2
0.15
0.1
0.05
0
0
0.02
0.05
0.1
0.15
0.2
0.25
0.4
0.5
0.6
0.8
1
1.2
Po (W)
Figure16 Supply Current vs Output Power (RL=8Ω
Ω
+33uH)
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- Page 12 of 12 -
Ver1.3
BL6311
Audio Precision
06/30/08 10:50:51
200m
40m
100m
20m
0
V
0
V
-100m
-20m
-200m
-40m
0
5m
10m
15m
20m
25m
30m
s
Sweep
Trace
Color
Line Style
Thick Data
Axis
1
1
1
2
Cyan
Green
Solid
Solid
1
1
Left
Right
FFT.ChA Amplitude
FFT.ChB Amplitude
Comment
Figure17 GSM Power Supply Rejection vs Time
Audio Precision
-20
+100
+75
-40
+50
V
D
D
(
d
B
V
)
-60
+25
V
o
+0
-80
(
-25
-100
-50
-75
-120
d
B
V
)
-100
-140
-125
0
200
400
600
800
1k
1.2k
1.4k
1.6k
1.8k
2k
Hz
Sweep Trace Color
1
1
1
2
Line Style Thick Data
Cyan Solid
Green Solid
1
1
Axis
Comment
FFT.ChAAmplitude Left
FFT.ChBAmplitude Right
Figure18 GSM Power Supply Rejection vs Frequency
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- Page 13 of 13 -
Ver1.3
BL6311
Package Dimensions
9 Bump WLCSP Dimensions
(mm)
REF
A1
A2
A3
D
D1
E
E1
b
CCC
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- Page 14 of 14 -
MIN
0.215
0.355
0.020
1.485
1.485
0.300
TYP MAX
0.235 0.255
0.380 0.405
0.035 0.050
1.500 1.515
0.500
1.500 1.515
0.500
0.320 0.340
0.080
Ver1.3