English

BL6211
1.25 Watt Fully Differential Audio Power Amplifier With
Internal Feedback Resistors
1
FEATURES
Fully differential amplifier
Improved PSRR at 217Hz(VDD>3.0V)
86dB (typ)
Power output at 5.0V & 1% THD
1.25W (typ)
Power output at 3.6V & 1% THD
0.6W (typ)
Ultra low shutdown current
0.01μA (typ)
Improved pop & click circuitry eliminates noises during turn-on and turn-off transitions
Thermal overload protection circuitry
No output coupling capacitors, bootstrap capacitors required
Unity-gain stable
External gain configuration capability
Available in space-saving package: 9-bump micro SMD and 8-pin MSOP8
2
GENERAL DESCRIPTION
The BL6211 is a fully differential audio power amplifier designed for portable communication device
applications. It is capable of delivering 1.25 watt of continuous average power to an 8Ω BTL load with
less than 1% distortion (THD+N) from a 5V battery voltage. It operates from 2.2 to 5.5V.
Features like 86dB PSRR at 217Hz, improved RF-rectification immunity, the space-saving 8-pin MSOP8
and 9-bump micro SMD package, the advanced pop & click circuitry, a minimal count of external
components and low-power shutdown mode make BL6211 ideal for wireless handsets.
The BL6211 is unity-gain stable, and the gain can be configured by external input resistors and internal
feedback resistors.
3
APPLICATIONS
Wireless handsets
Portable audio devices
PDAs, Handheld computers
http://www.belling.com.cn
BL6211
4
TYPICAL APPLICATION
CS
1μF
VDD
Differential Audio Input
0.39μF
Ci
20kΩ
Ri
Rf
40kΩ
IN-
VIH
SHUTDOWN
VIL
Ci
0.39μF
Bias VDD/2
Circuitry
BYPASS
C B 1μF
C B is optional
GND
5
VO2
40kΩ
20kΩ
Figure 1
RL
8Ω
+
IN+
Ri
VO1
+
BL6211
-
Rf
Typical Audio Amplifier Application Circuit
ORDER INFORMATION
Table 1.
Order information
Part Number
Marking
Package
Shipping
BL6211ITLX
AAG
9 Bump micro SMD
3000 pcs / Tape & Reel
BL6211MM
ABG
8-pin MSOP8
3000 pcs / Tape & Reel
http://www.belling.com.cn
BL6211
6
PIN DESCRIPTIONS
6.1 Pin Diagram (Top View)
Mini Small O utline (MSO P8) Package
(Top View)
SHUTDOWN
BYP ASS
IN+
IN-
1
8
2
7
3
6
4
5
MSO P8 Marking
VO2
EG
ABG
GND
VDD
VO1
E - Die Run Traceability
G - Date Code
ABG - BL6211MM ROHS
Figure 2
Pin Diagram of BL6211
6.2 Pin Definitions and Functions
Table 2.
Pin Definitions and Functions
MSOP8
9-Bump
micro SMD
Symbol
Type
1
C3
SHUTDOWN
I
Shutdown Pin, active low.
2
C1
BYPASS
I
Common mode voltage. Connect a bypass
capacitor to GND for common mode voltage
filtering. The bypass capacitor is optional.
3
A3
IN+
I
Positive differential input.
4
A1
IN-
I
Negative differential input.
http://www.belling.com.cn
Functions
BL6211
7
MSOP8
9-Bump
micro SMD
Symbol
Type
5
A2
VO1
O
Positive differential output.
6
B3
VDD
I
Power supply
7
B1,B2
GND
I
Ground.
8
C2
VO2
O
Negative differential output.
Functions
OPERATION CONDITIONS AND ELECTRICAL CHARACTERISTICS
7.1 Absolute Maximum Ratings (note 1)
Supply voltage, VDD……………………………………………-0.3V to 6.0V
Input voltage…………………………………………….-0.3V to VDD +0.3V
Storage Temperature..………………………………………...-65℃ to 150℃
Power Dissipation (note2)………………………………….Internally Limited
ESD Parameters:
ESD Protection (HBM, 1.5kΩ and 100pF in series)………….………...2000V
ESD Protection (MM, 200pF, no resistor) ................………………........200V
Junction temperature, TJ……………………………………....-40℃ to 150℃
Thermal Resistance θJA (micro SMD)…………………………… ..220℃/W
Thermal Resistance θJC (MSOP)………………………………… …56℃/W
Thermal Resistance θJA (MSOP)………………………………… ..190℃/W
Lead Temperature (Soldering, 10 sec)…………………………………. 300℃
Note1: stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device.
These are stress ratings only, and functional operation of the device at these or any other conditions beyond those
indicated under “recommended operating conditions” is not implied. Exposure to absolute maximum rated conditions
for extended periods may affect device reliability.
Note2: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX, θJA, and
the ambient temperature TA. The maximum allowable power dissipation is PDMAX=(TJMAX-TA)/θJA or the number
given in Absolute Maximum Ratings, whichever is lower.
7.2 Operation Conditions
Table 3.
Operation Conditions
Parameter
Symbol
Min
Power Supply Voltage
VDD
Operating Temperature Range
TA
http://www.belling.com.cn
Typ
Max
Unit
2.2
5.5
V
-40
85
℃
BL6211
7.3 Electrical Characteristics
Table 4.
VDD=5V (The following specifications apply for 8Ωload，AV=1V/V，TA=25℃, unless
otherwise specified.)
Parameter
Symbol
Conditions
Typ
Max
VIN=0V, no load
2.5
5
VIN=0V, RL=8Ω
4
8
0.01
1
Quiescent Power
Supply Current
IDD
Shutdown Current
ISD
VSHUTDOWN=GND
Output Power
PO
THD=1%(max);
Total Harmonic
Distortion + Noise
THD+N
PO=0.6Wrms;
Min
f=1kHz
f=1kHz
Unit
mA
µA
1.25
W
0.02
%
Vripple=200mV sine p-p
Power Supply
Rejection Ratio
PSRR
f=217Hz (note1)
-88
f=1kHz (note1)
-83
f=217Hz (Note2)
-83
F=1KHz (Note2)
-83
Common Mode
Rejection Ratio
CMRR
f=217Hz
Output Offset
VOS
VIN=0V
Shutdown Voltage
Input High
VSDIH
Shutdown Voltage
Input Low
VSDIL
Closed Loop Gain
AV
Note1: Unterminated input
Note2: 10Ωterminated input
http://www.belling.com.cn
VCM=200mVPP
dB
-78
2
dB
8
1.5
36kΩ
Ri
mV
V
40kΩ
Ri
0.5
V
44kΩ
Ri
V/V
BL6211
Table 5.
VDD=3.6V (The following specifications apply for 8Ωload，AV=1V/V，TA=25℃, unless
otherwise specified.)
Parameter
Symbol
Conditions
Typ
Max
VIN=0V, no load
2
4.5
VIN=0V, RL=8Ω
3.5
7.5
0.01
1
Quiescent Power
Supply Current
IDD
Shutdown Current
ISD
VSHUTDOWN=GND
Output Power
PO
THD=1%(max);
Total Harmonic
Distortion + Noise
THD+N
PO=0.4Wrms;
Min
f=1kHz
f=1kHz
Unit
mA
µA
0.6
W
0.02
%
Vripple=200mV sine p-p
Power Supply
Rejection Ratio
PSRR
f=217Hz (note1)
-86
f=1kHz (note1)
-83
f=217Hz (Note2)
-83
F=1KHz (Note2)
-83
Common Mode
Rejection Ratio
CMRR
f=217Hz
Output Offset
VOS
VIN=0V
Shutdown Voltage
Input High
VSDIH
Shutdown Voltage
Input Low
VSDIL
Closed Loop Gain
Gain
Note1: Unterminated input
Note2: 10Ωterminated input
http://www.belling.com.cn
VCM=200mVPP
dB
-76
2
dB
8
1.5
36kΩ
Ri
mV
V
40kΩ
Ri
0.5
V
44kΩ
Ri
V/V
BL6211
8
TYPICAL CHARACTERISTICS
Output Power vs Supply Voltage
RL=8Ω
Power Dissipation vs Output Power
2.0
0.7
1.8
0.6
Power Disspation(W)
Output Power(W)
1.6
1.4
1.2
THD+N=10%
1.0
THD+N=1%
800m
600m
0.5
0.4
0.3
VDD=5V
f=1KHz
0.2
THD+N ≤1%
400m
RL=8Ω
0.1
200m
0
2.2
0
2.5
3
3.5
4
4.5
5
0
5.5
0.2
0.3
0.6
0.25
0.2
0.15
VDD=3.6V
f=1KHz
0
1.0
1.2
MSOP
0.4
0.3
0.2
Micro SMD
0.1
RL=8Ω
0
0.8
0.5
THD+N ≤1%
0.05
0.6
Power Derating Curve
0.7
Power Disspation(W)
Power Disspation(W)
Power Dissipation vs Output Power
0.35
0.1
0.4
Output Power(W)
Supply Voltage(V)
0.2
0.4
Output Power(W)
http://www.belling.com.cn
0.6
0.8
0
0
20
40
60
80
100
120
Ambient Temperature (℃)
140
160
BL6211
THD+N vs Frequency
VDD=3.6V, RL=8Ω,PO=400mW
10
10
1
1
THD+N (%)
THD+N (%)
THD+N vs Frequency
VDD=5V, RL=8Ω,PO=600mW
0.1
0.01
0.1
0.01
0.001
0.001
20
100
1K
10K 20K
20
100
Frequency (Hz)
10
1
1
20kHz
0.1
1kHz
THD+N (%)
THD+N (%)
10
0.1
0.01
0.01
0.001
100
1K
Frequency (Hz)
http://www.belling.com.cn
10K 20K
THD+N vs Output Power
VDD=5V, RL=8Ω
THD+N vs Frequency
VDD=2.5V, RL=8Ω,PO=150mW
20
1K
Frequency (Hz)
10K 20K
20Hz
0.001
10m
100m
Output Power (W)
1
2
BL6211
THD+N vs Output Power
VDD=3.6V, RL=8Ω
THD+N vs Output Power
VDD=2.5V, RL=8Ω
10
1
20kHz
0.1
1kHz
THD+N (%)
THD+N (%)
10
20Hz
0.01
1
20kHz
0.1
1kHz
0.01
0.001
10m
100m
20Hz
0.001
10m
1
100m
Output Power (W)
PSRR vs Frequency
VDD=3.6V, RL=8Ω,input 10Ω Terminated
0
0
-10
-10
-20
-20
-30
-30
PSRR (dB)
PSRR (dB)
PSRR vs Frequency
VDD=5.0V, RL=8Ω,input 10Ω Terminated
-40
-50
-60
1
Output Power (W)
C(BYPASS)=0μF
-70
-40
-50
-60
C(BYPASS)=0μF
-70
-80
C(BYPASS)=0.47μF
-90
-80
C(BYPASS)=0.47μF
-90
C(BYPASS)=1μF
-100
C(BYPASS)=1μF
-100
20
100
1K
Frequency (Hz)
http://www.belling.com.cn
10K 20K
20
100
1K
Frequency (Hz)
10K 20K
BL6211
PSRR vs Common Mode voltage
VDD=3.6V, RL=8Ω, 217Hz, 200mVPP
0
0
-10
-10
-20
-20
-30
-30
PSRR (dB)
-40
-50
-60
-40
-50
-60
-70
-70
-80
-80
-90
-90
-100
-100
0
1
2
3
4
0
5
200
40
160
160
30
120
120
20
80
80
10
Gain
40
0
3.6
3
220
Phase
180
140
100
Gain
60
0
-10
20
-20
-20
-80
-30
-60
-40
-40
-80
Phase
Gain (dB)
200
0
2
Closed Loop Frequency Response
Phase (O)
Gain (dB)
Open Loop Frequency Response
40
1
DC Common-Mode Voltage (V)
DC Common-Mode Voltage (V)
-120
-40
-100
-160
-160
-50
-140
-200
-200
10M
-60
-120
100
1k
10k
100K
Frequency (Hz)
http://www.belling.com.cn
1M
100
1k
10k
100K
Frequency (Hz)
1M
-180
10M
Phase (O)
PSRR (dB)
PSRR vs Common Mode voltage
VDD=5.0V, RL=8Ω, 217Hz, 200mVPP
BL6211
9
APPLICATION INFORMATION
9.1 Fully Differential Amplifier Description
The BL6211 is a fully differential amplifier with differential inputs and outputs. The fully differential
amplifier consists of a differential amplifier and a common mode amplifier. The differential amplifier
ensures that the amplifier outputs a differential voltage that is equal to the differential input times the gain.
The common mode feedback ensures that the common-mode voltage at the output is biased around
VDD/2 regardless of the common-mode voltage at the input.
The BL6211 provides a "bridged mode" output configuration (bridge-tied-load, BTL). This means the
output signals at Vo1 and Vo2 that are 180° out of phase with respect to each other. Bridged mode
operation is different from the single-ended output configuration that connects the load between the
amplifier output and ground. A bridged amplifier design has distinct advantages over the single-ended
output configuration: it provides differential drive to the load, thus doubling maximum possible output
swing for a specific supply voltage. Four times the output power is possible compared with a single-ended
output configuration under the same conditions. This increase in attainable output power assumes that the
amplifier is not current limited or clipped.
9.2 Advantages of Fully Differential Amplifier
Input and output coupling capacitor not required: A fully differential amplifier with good CMRR, the
BL6211 allows the input signal to be biased at voltage other than mid-supply of the BL6211, the
common-mode feedback circuit adjusts for it, and the outputs are still biased at mid-supply of the
BL6211.
Mid-supply bypass capacitor, CBYPASS not required: The fully differential amplifier does not require a
bypass capacitor. It is because any shift in the mid-supply affects both positive and negative channels
equally and cancels the differential output. However, removing the bypass capacitor slightly worsens
power supply rejection ration, but a slightly decrease of PSRR may be acceptable when an additional
component can be eliminated.
Better RF-immunity: GSM handsets save power by turning on and shutting off the RF transmitter at a rate
of 217Hz. The transmitted signal is picked-up on input and output traces. The fully differential amplifier
reduces the RF rectification much better than the typical audio amplifier.
http://www.belling.com.cn
BL6211
9.3 Applications
From Figure 3 to Figure 5 show application schematics for differential and single-ended inputs.
CS
1μF
VDD
Differential Audio Input
20kΩ
Ri
Rf
40kΩ
IN-
VO1
VIH
SHUTDOWN
VIL
C B 1μF
C B is optional
Ri
+
BL6211
-
Bias VDD/2
Circuitry
BYPASS
IN+
+
40kΩ
20kΩ
GND
Figure 3
http://www.belling.com.cn
Rf
Typical Differential Input Application
RL
8Ω
VO2
BL6211
CS
1μF
VDD
Differential Audio Input
0.39μF
Ci
20kΩ
Ri
Rf
40kΩ
IN-
VO1
VIH
SHUTDOWN
VIL
C B 1μF
C B is optional
Ci
0.39μF
Ri
+
BL6211
-
Bias VDD/2
Circuitry
BYPASS
IN+
40kΩ
GND
http://www.belling.com.cn
VO2
+
20kΩ
Figure 4
RL
8Ω
Rf
Differential Input Application With Input Capacitors
BL6211
CS
1μF
VDD
Audio
Input
0.39μF
Ci
20kΩ
Ri
Rf
40kΩ
IN-
VO1
VIH
SHUTDOWN
VIL
C B 1μF
C B is optional
Ci
0.39μF
+
BL6211
-
Bias VDD/2
Circuitry
BYPASS
RL
8Ω
VO2
+
IN+
Ri
40kΩ
20kΩ
GND
Figure 5
Rf
Single-Ended Input Application
9.4 Proper Selection of external Components
9.4.1
Input Resistor (Ri)
The input (Ri) and internal feedback resistors, Rf=40kΩ, set the gain of the amplifier according to
Equation 1:
Gain= 40kΩ/ Ri
(1)
In order to optimize the THD+N and SNR performance, The BL6211 should be used in low closed-loop
gain configuration. Ri should be in range from 1kΩ to 100kΩ. Resistor matching is very important for
fully differential amplifiers. The balance of the output on the common mode voltage depends on matched
ratios of the resistors. CMRR, PSRR, and the second harmonic distortion is increased if resistor is not
matched. Therefore, it is recommended to use 1% tolerance resistors or better to keep the performance
optimized.
9.4.2
Input Capacitor (Ci)
The input coupling capacitor blocks the input DC voltage. The BL6211 does not require input coupling
capacitors if using a differential input source that is biased from 0.5V to VDD-0.8V. Use 1% tolerance or
better resistors if not using input coupling capacitors. In the single-ended input application an input
capacitor, Ci, is required to allow the amplifier to bias the input signal to the proper dc level.
The Ci and Ri form a high-pass filter with the corner frequency determined in Equation 2.
fC =
http://www.belling.com.cn
1
2πRiCi
(2)
BL6211
-3dB
fC
Special care should be taken to the value of Ci because it directly affects the low frequency performance
of the system. For example, assuming Ri is 20kΩ and the specification calls for a flat response down to
100Hz. From Equation 2, Ci is 0.08uF, so Ci would likely choose a value in the range of 0.068µF to
0.47µF. A further consideration for Ci is the leakage path from the input source through the input network
(Ri, Ci) and the feedback resistor (Rf) to the load. This leakage current creates a DC offset voltage that
reduces useful headroom, especially in high gain applications. For this reason, a ceramic capacitor is the
best choice.
9.4.3
Bypass Capacitor (CBYPASS) and Start-Up Time
Connecting a capacitor to BYPASS pin filters any noise into this pin and increases the PSRR
performance. CBYPASS also determines the rise time of VO1 and VO2, the larger the capacitor, the slower
the rise time, the BL6211 start to work after the CBYPASS voltage reaches the mid-supply voltage. This
capacitor can also minimize the pop & click noise during turn-on and turn-off transitions, the larger the
capacitor, the smaller the pop & click noise, 1µF capacitor is recommended for CBYPASS.
9.4.4
Decoupling Capacitor (CS)
Power supply decoupling is critical for low THD+N and high PSRR performance. A low
equivalent-series-resistance (ESR) ceramic capacitor, typically 0.1µF to 1µF, placed as close as possible
to VDD pin make the device works better. For filtering lower frequency noise signals, a 10µF or greater
capacitor placed near the audio power amplifier also helps, but it is not required in most applications
because of the high PSRR of this device.
9.5 USING LOW-ESR CAPACITORS
Low-ESR capacitors are recommended. A real capacitor can be modeled simply as a resistor in series
with an ideal capacitor. The voltage drop across this resistor minimizes the beneficial effects of the
capacitor in the circuit. The lower the equivalent value of this resistance the more the real capacitor
behaves like an ideal capacitor.
9.6 POWER DISSIPATION
Power dissipation is a major concern when designing a successful amplifier, whether the amplifier is
bridged or single-ended. Equation 3 states the maximum power dissipation point for a single-ended
amplifier operating at a given supply voltage and driving a specified output load.
PDMAX =
http://www.belling.com.cn
(VDD )2
(2π
2
RL )
Single-Ended
(3)
BL6211
However, a direct consequence of the increased power delivered to the load by a bridge amplifier is an
increase in internal power dissipation versus a single-ended amplifier operating at the same conditions.
PDMAX = 4 ∗
(VDD )2
(2π
2
RL )
Bridge-Ended
(4)
Since the BL6211 has bridged outputs, the maximum internal power dissipation is 4 times that of a
single-ended amplifier. Even with this substantial increasing in power dissipation, the BL6211 does not
require additional heat-sinking under most operating conditions and output loading. From Equation 4,
assuming a 5V power supply and an 8Ω load, the maximum power dissipation point is 625mW. The
maximum power dissipation point obtained from Equation 4 must not be greater than the power
dissipation results from Equation 5:
PDMAX = (TJMAX − TA ) / θ JA
(5)
Depending on the ambient temperature, TA, of the system surroundings, Equation 5 can be used to find
the maximum internal power dissipation supported by the IC packaging. If the result of Equation 4 is
greater than that of Equation 5, then either the supply voltage must be decreased, the load impedance
increased, the ambient temperature reduced, or the θJA reduced with heat-sinking. In many cases, larger
traces near the output, VDD, and GND pins can be used to lower the θJA. The larger areas of copper
provide a form of heat-sinking allowing higher power dissipation. Recall that internal power dissipation is
a function of output power. If the typical operation is not around the maximum power dissipation point,
the BL6211 can operate at higher ambient temperatures.
9.7
SHUTDOWN FUNCTION
In order to reduce power consumption while not in use, the BL6211 contains shutdown circuitry that is
used to turn off the amplifier’s bias circuitry. The shutdown pin should be tied to a definite voltage to
avoid unwanted state changes. In many applications, a microcontroller or microprocessor output is used
to control the shutdown circuitry, which provides a quick, smooth transition to shutdown. Another
solution is to use a single-throw switch in conjunction with an external pull-down resistor. This scheme
guarantees that the shutdown pin will not float, thus preventing unwanted state changes.
9.8 PCB LAYOUT
The residual resistance of the PCB trace between the amplifier output pins and the speaker causes a
voltage drop, which results in power dissipated in the PCB trace and not in the speaker as desired.
Therefore, to maintain the highest speaker power dissipation and widest output voltage swing, PCB trace
that connects the amplifier output pins to the speaker must be as wide as possible.
Poor power supply regulation adversely affects maximum output power. A poorly regulated supply’s
output voltage decreases with increasing load current. Reduced supply voltage causes decreased
headroom, output signal clipping, and reduced output power. Even with tightly regulated supplies, power
supply trace resistance creates the same effects as poor supply regulation. Therefore, making the power
supply trace as wide as possible helps to maintain full output voltage swing.
It is very important to keep the BL6211 external components very close to the BL6211 to limit noise
pickup.
http://www.belling.com.cn
BL6211
10
PHYSICAL DIMENSIONS
SYMM
cL
9x
0.275
0.250
SYMM cL
(0.5)
DIMENSIONS ARE IN MILLIMETERS
(0.5)
LAND PATTERN RECOMMENDATION
B
X3
X2
SYMM
cL
C
BUMP
3
SYMM
cL
X1
2
0.5
1
BUMP A1 CORNER
SILICON
0.265
0.215
C
9x
0.31
0.29
B
0.5
0.005 S C AS BS
9-Bump micro SMD
Part Number BL6211ITLX
X1=1.514±0.03 X2=1.514±0.03 X3=0.600±0.075
A
A
BL6211
(continued)
PHYSICAL DIMENSIONS
DIMENSIONS ARE IN MILLIMETERS
LAND P ATTERN
RECOMMENDATION
B
3±0.1
8
5
C
4.8
1.02
4.9±0.15
3±0.1
0.41
0.65
PIN 1
IDENT
1
4
6× 0.65
0.86
1.09 MAX
0.1
A
0.06-0.15
TYP
0.3
+0.10
0.18±0.05
TYP
-0.05
0.05
M
B
S
C
S
0.953 T YP
Mini Small Outline (MSOP8)
Part Number BL6211MM
http://www.belling.com.cn
GAGE PLANE
R 0.13
TYP
R 0.13
TYP
0.25
A
0.53±0.12
TYP
SEATING
PLANE
0o-6o
TYP