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
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
for
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
Pin Diagrams
9 Bump WLCSP Marking
(Top View)
9 Bump WLCSP Package
(Top View)
1
2
3
IN+
GND
VO-
1
2
3
A
A
B
B
VDD
PVDD
PGND
C
IN-
SDB
VO+
6311
YYWW
C
YY - Year Code
WW - Week Code
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- Page 1 of 14 -
Ver1.6
BL6311
Pin Description
Pin #
Name
Description
A1
IN+
Positive differential input
A2
GND
Power Ground
A3
VO-
Negative BTL output
B1
VDD
Power Supply
B2
PVDD
Power Supply
B3
PGND
Power Ground
C1
IN-
Negative differential input
C2
SDB
Shutdown terminal (low active)
C3
VO+
Positive BTL output
Function Block Diagram
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 2 of 14 -
Ver1.6
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 3 of 14 -
Ver1.6
BL6311
Absolute Maximum Ratings
Supply voltage
-0.3V to 6V
Input voltage
-0.3V to VDD+0.3V
Junction Temperature
-40
to +150
Storage Temperature
-65
to +150
Note: Stresses beyond those listed under “absolute maximum ratings” may cause permanent
damage to the device.
Recommended Operating Conditions
Min
Max
Unit
Supply Voltage
2.5
5.5
V
Shutdown Voltage Input High
1.3
VDD
V
Shutdown Voltage Input Low
0
0.4
V
Electrical Characteristics
The following specifications apply for the circuit shown in Figure 5.
TA = 25 , unless otherwise specified.
Symbol
ISD
IQ
Parameter
Shutdown Current
Quiescent Current
VOS
Output Offset Voltage
PSRR
Power Supply Rejection Ratio
Conditions
Spec
Min.
Typ.
Max.
VIN=0V, VSDB=0V, No Load
0.4
2
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
3.0
8
2
25
VIN = 0V, AV = 2V/V,
VDD = 2.5V to 5.5V
VDD = 2.5V to 5.5V
Units
uA
mA
mV
-75
dB
-68
dB
VDD = 2.5V to 5.5V,
CMRR Common Mode Rejection Ratio
VIC = VDD/2 to 0.5V,
VIC = VDD/2 to VDD - 0.8V
FSW
Modulation frequency
VDD = 2.5V to 5.5V
200
250
300
kHz
AV
Voltage gain
VDD = 2.5V to 5.5V
285k
RI
300k
RI
315k
RI
V/V
RSDB
ZI
Resistance from SDB to GND
300
Input impedance
TWU
rDS(on)
Wake-up time from shutdown
142
150
VDD = 3.6V
1
VDD = 2.5V
700
Drain-Source resistance (on-state) VDD = 3.6V
500
VDD = 5.5V
400
kΩ
158
kΩ
mS
mΩ
Operating Characteristics
VDD = 5V, RI = 150kΩ, TA = 25
Symbol
Parameter
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, unless otherwise specified.
Conditions
- Page 4 of 14 -
Spec
Min.
Typ.
Max.
Units
Ver1.6
BL6311
PO
THD+N
SNR
Total Harmonic
Distortion + Noise
3.0
THD+N=1%, f=1KHz, RL = 4Ω
2.4
THD+N=10%, f=1KHz, RL = 8Ω
1.7
THD+N=1%, f=1KHz, RL = 8Ω
1.4
Po=1.0Wrms, f=1kHz, RL = 8Ω
0.19
%
97
dB
Signal-to-Noise ratio VDD=5V, Po=1.0Wrms, RL = 8Ω
W
VDD = 3.6V, RI = 150kΩ, TA = 25 , unless otherwise specified.
Symbol
PO
THD+N
KSVR
Vn
CMRR
Output Power
THD+N=10%, f=1KHz, RL = 4Ω
Parameter
Output Power
Total Harmonic
Distortion + Noise
Spec
Conditions
Min.
THD+N=1%, f=1KHz, RL = 4Ω
1.2
THD+N=10%, f=1KHz, RL = 8Ω
0.9
THD+N=1%, f=1KHz, RL = 8Ω
0.7
Po=0.5Wrms, f=1kHz, RL = 8Ω
0.19
%
-68
dB
rejection ratio
f=217Hz, V(Ripple)=200mVPP
Rejection Ratio
Units
1.5
VDD = 3.6V, input ac-grounded with CI = 2uF
Common Mode
Max.
THD+N=10%, f=1KHz, RL = 4Ω
Supply ripple
Output voltage noise
Typ.
VDD = 3.6V, input ac-grounded No weighting
48
with CI = 2uF, f=20~20kHz
36
A weighting
VDD = 3.6V, VIC = 1 VPP, f=217Hz
W
uVRMS
-70
dB
VDD = 2.5V, RI = 150kΩ, TA = 25 , unless otherwise specified.
Symbol
PO
THD+N
Parameter
Output Power
Total Harmonic
Distortion + Noise
Conditions
Spec
Min.
Typ.
THD+N=10%, f=1KHz, RL = 4Ω
0.7
THD+N=1%, f=1KHz, RL = 4Ω
0.55
THD+N=10%, f=1KHz, RL = 8Ω
0.4
THD+N=1%, f=1KHz, RL = 8Ω
0.3
Po=0.2Wrms, f=1kHz, RL = 8Ω
0.19
Max.
Units
W
%
Test Circuit
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- Page 5 of 14 -
Ver1.6
BL6311
Ci
Ri
IN+
2uF
Signal input
from
measurement
VO+
150K
Vin
BL6311
Ci
Ri
IN2uF
30
LP
RL
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
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.
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- Page 6 of 14 -
Ver1.6
BL6311
(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 high-impedance 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 ~ VDD-0.8V (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 ⋅ R I ⋅ 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
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)
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- Page 7 of 14 -
Ver1.6
BL6311
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)
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)
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- Page 8 of 14 -
Ver1.6
BL6311
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
Comment
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
Po=25mW
Po=125mW
Po=500mW
Figure10. THDN vs Frequency (VDD=3.6V 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
1
2
3
Green Solid
Cyan
Solid
Yellow Solid
1
1
1
Line Style Thick Data
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)
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- Page 9 of 14 -
Ver1.6
BL6311
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)
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
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)
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- Page 10 of 14 -
Ver1.6
BL6311
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
Figure14. PSRR vs Frequency (RL=8ohm, Input floating)
fficiency vs Po
1
0 9
0
fficiency
0
0
0 5
0
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
Po
0 5 0
0
1
1 2
Figure15. Efficiency vs Po (RL=8 +33uH)
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- Page 11 of 14 -
Ver1.6
BL6311
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
0 5
0
0
1
1 2
Po (W)
Figure16. Supply Current vs Output Power (RL=8 +33uH)
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- Page 12 of 14 -
Ver1.6
BL6311
Audio Precision
300m
40m
200m
20m
100m
V
0
0
-100m
V
-20m
-200m
-40m
-300m
0
5m
10m
15m
20m
25m
30m
s
Sweep
Trace
Color
Line Style
Thick
Data
Axis
Comment
1
1
1
2
Green
Cyan
Solid
Solid
1
1
FFT.ChA Amplitude
FFT.ChB Amplitude
Left
Right
GSM signal added to VDD
Vout
Figure17. GSM Power Supply Rejection vs Time
Audio Precision
-20
+100
-40
+50
-60
d
B
V
-80
d
B
V
+0
-100
-50
-120
-140
-100
-160
250
500
750
1k
1.25k
1.5k
1.75k
2k
Hz
Sweep
Trace
Color
Line Style
Thick
Data
Axis
Comment
1
1
1
2
Green
Cyan
Solid
Solid
1
1
FFT.ChA Amplitude
FFT.ChB Amplitude
Left
Right
GSM signal added to VDD
VOUT
Figure18. GSM Power Supply Rejection vs Frequency
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- Page 13 of 14 -
Ver1.6
BL6311
Package Dimensions
9 Bump WLCSP Dimensions (mm)
REF
MIN
TYP
MAX
A1
0.215
0.235
0.255
A2
0.355
0.380
0.405
A3
0.020
0.035
0.050
D
1.490
1.520
1.550
D1
E
0.500
1.490
E1
b
CCC
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- Page 14 of 14 -
1.520
1.550
0.500
0.300
0.320
0.340
0.080
Ver1.6