ETC BA3101

10W Stereo Class D Audio
Power Amplifier
BA3101
Data Sheet
Rev.1.0, 2009.08.01
Biforst Technology Inc.
Page 0 of 7
BA3101
10W Stereo Class D Audio Power Amplifier
10W Stereo Class D Audio Power Amplifier
GENERAL DESCRIPTION
The BA3101 is a 12V class D amplifier from Biforst Technology. BA3101 provide volume
control with four selectable gain settings. BA3101 is a 10-W (per channel) with lower supply
current and fewer external components for driving bridged-tied stereo speaker directly.
BA3101 operates with high efficiency energy conversion up to 89% (8-Ω Load) so that the
external heat sink can be eliminated while playing music. Two gain select pins, GAIN0 and
GAIN1, control the two controllable gain values, with firm gain selections are 20dB, 26dB, 32dB,
36dB.
BA3101 also integrates Anti-Pop, Output Short & Over-Heat Protection Circuitry to ensure
device reliability. This device output are completely protected from shorts to ground or supply pin
as well as protected from Output Pin to Output Pin short. All the output short protection features
are auto restore and auto monitor.
FEATURE
9.2W Per Channel Into 8-Ω Speakers (THD+N = [email protected])
10.8W Per Channel into 8-Ω Speakers (THD+N = [email protected])
Operation Voltage From 8V To 15V
Maximum Power Efficiency Into 8-Ω, 89%
Total four selectable, firm-gain solution
Differential input
Automatic monitor and restore scheme for short and over heat protection
Clock synchronization master/slave for multiple Class D device
Eliminates output clamp and bypass capacitors
Package is SMD 7mm * 7mm 48 Pins TQFP-with Exposed Thermal Pad
APPLICATION
LCD TV
LCD Monitor
Powered Speaker
Hi-Fi Audio System
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BA3101
10W Stereo Class D Audio Power Amplifier
These devices have limited built-in ESD protection. The lead should be shorted together or the device placed in
conductive foam during storage or handling to prevent electrostatic damage to the device.
ABSOLUTE MAXIMUM RATINGS
Over operating free-air temperature range, unless otherwise specified (* 1)
SYMBOL
PARAMETER
VALUE
UNIT
VDD, PVDDL, PVDDR
Supply voltage
-0.3 to 15
V
VI( SHUTDOWN , MUTE)
Input voltage
-0.3 to VCC+0.3
V
Input voltage
-0.3 to VREG+0.5
V
Operating free-air temperature range
-40 ~ +85
o
-40 to +150
o
o
VI(GAIN0, GAIN1, RINN,
RINP, LINN, LINP, MSTR/ SLV ,
SYNC)
TA
TJ
(* 2)
Operating junction temperature range
C
C
TSTG
Storage temperature range
-65 to 85
C
R(Load)
Minimum load resistance
8
Ω
Electrostatic discharge
Human body model
±2
kV
Electrostatic discharge
Machine model
±200
V
( *1): Stress beyond those listed at “absolute maximum rating” table may cause permanent damage to the device. These are
stress rating ONLY. For functional operation are strongly recommend follow up “recommended operation conditions” table.
( *2): BA3101 package embedded with an exposed thermal PAD underside of package. The exposed PAD performs the function
of heat sink and it have to be connected to a thermally dissipating plane for power dissipation. Failure to do so will result in the
device going into thermal protection shutdown.
PACKAGE DISSPATION RATINGS
PACKAGE
θja(junction to ambient air)
θjc(junction to case)
TQFP 48 pin with Expose Pad
35.24
7.14
UNIT
℃
mW/
*This data was taken using 1 oz copper pad that is soldered directly to FR-4 PCB. The thermal pad must be soldered to the thermal land on PCB.
RECOMMENDED OPERATING CONDITIONS
Over operating free-air temperature range, unless otherwise specified
SYMBOL
PARAMETER
VDD
Supply voltage
TEST CONDITION
VDD
,PVDDL,PVDDR
SPECIFICATION
MIN
MAX
8
15
UNIT
V
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BA3101
SYMBOL
VIH
VIL
IIH
10W Stereo Class D Audio Power Amplifier
PARAMETER
High level input
voltage
Low level input
voltage
High level input
current
Low level input
current
VOH
VOL
fOSC
TA
High level output
voltage
MIN
,MSTR/ SLV ,SYNC,GAIN0,
GAIN1,MUTE
SHUTDOWN ,MSTR/ SLV ,SYNC MUTE,
GAIN0,GAIN1
V =V ,V =15 V
MUTE,V =V ,V =15 V
V =V ,V =15 V
V =V ,V =15 V
V =0 V,V =12 V
FAULT,I =1 mA,
SHUTDOWN
I
DD
REG
I
DD
FAULT
0.8
2
2
DD
1
OL=-1
uA
80
DD
,I
V
150
DD
OH
voltage
V
DD
I
Low level output
Oscillator frequency
DD
UNIT
MAX
2.0
DD
I
I
IIL
SPECIFICATION
TEST CONDITION
uA
V
VREG-0.6
,
mA
,MSTR/ SLV = 2 V
ROSC Resistor = 100 kΩ
Operating free-air
temperature
AGND +0.4
V
250
300
kHZ
- 40
85
o
C
DC CHARACTERISTICS
TA = 25
℃, VDD= 12V, RL = 8Ω, Gain =20dB (unless otherwise noted)
SYMBOL
VREG
VBYP
|PSRR|
PARAMETER
5V internal supply
voltage
Bypass reference
for input amplifier
DC power supply
rejection ratio
Drain-Source
RDS(ON)
TEST CONDITION
on –state
resistance
G
TYP
MAX
No load
4.5
5
5.5
V
No load
1.15
1.25
1.35
V
VDD=12V, PO=8W,
GAIN0=L
Gain
GAIN0=H
UNIT
MIN
VDD=12V, input AC tie ground, Gain=36dB
RL=8Ω
SPECIFICATION
70
High Side
365
Low Side
365
GAIN1=L
20
GAIN1=H
26
GAIN1=L
32
GAIN1=H
36
dB
mΩ
dB
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BA3101
10W Stereo Class D Audio Power Amplifier
SPECIFICATION
SYMBOL
PARAMETER
TEST CONDITION
TON
Turn-On time
C(VBYP)=1µF, SHUTDOWN =H
25
ms
TOFF
Turn-Off time
C(VBYP)=1µF, SHUTDOWN =L
0.1
ms
Quiescent
MIN
SHUTDOWN =H, MUTE=L, no load, no
TYP
MAX
UNIT
24
filter, no snubber
ICC
Mute mode
SHUTDOWN =H, MUTE=H, no load, no
mA
11
filter, no snubber
Shutdown mode
SHUTDOWN =L, no load, no filter, no
200µA
snubber
AC CHARACTERISTICS
TA = 25
℃, VDD= 12V, RL = 8Ω, Gain =20dB (unless otherwise noted)
SYMBOL
|Ksvr|
THD+N
|Crosstalk|
PO
PARAMETER
TEST CONDITION
Supply ripple
200mVPP ripple from 20Hz-1kHz, input AC
rejection
tie ground
Total harmonic
distortion and noise
Crosstalk between
L/R channel
Continuous output
power
f=1kHz
SPECIFICATION
MIN
TYP
MAX
UNIT
70
dB
f=1kHz, PO=5W
0.17
%
Vo=1VRMS,f=1kHz
90
dB
THD+N=1%
7.4
THD+N=10%
9.2
VDD=13V,THD+N=10%
10.8
W
SNR
Signal to noise ratio
THD+N=1%, A-weighted, f=1kHz
93
dB
VN
Output noise
22Hz to 22kHz, A-weighted filter
150
µV
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BA3101
10W Stereo Class D Audio Power Amplifier
VDD
VDD
FAULT
MUTE
SHUTDOWN_B
N.C.
ROUTP
ROUTP
ROUTN
ROUTN
N.C.
GND
48
47
46
45
44
43
42
41
40
39
38
37
PIN ASSIGNMENTS
GND
1
36
RINN
2
35
PVDDR
RINP
3
34
PVDDR
GND
4
33
PVSSR
LINP
5
32
PVSSR
31
N.C.
30
N.C.
BA-3101
Exposed-Thermal PAD
GND
23
24
N.C.
22
GND
21
GND
LOUTN
25
LOUTN
12
20
GND
LOUTP
PVDDL
19
SYNC
26
18
PVDDL
11
N.C.
MSTR/SLV_B
LOUTP
PVSSL
27
17
28
10
GND
9
16
GAIN1
VBYP
PVSSL
VREG
29
15
8
14
GAIN0
13
7
GND
6
ROSC
LINN
GAIN0
PIN DESCRIPTION
Pin No.
Pin
I/O Pad Function
Type
Power ground
1
GND
POWER
2
RINN
Input
Right channel negative audio signal input
3
RINP
Input
Right channel positive audio signal input
4
GND
POWER
5
LINP
Input
Left channel positive audio signal input
6
LINN
Power
Left channel negative audio signal input
7~8
GAIN0
Input
Gain control input to select least significant bit
9
GAIN1
Input
Gain control input to select most significant bit
10
MSTR/ SLV
11
SYNC
12 ~ 13 GND
Power ground
Determine clock operating mode. While this pin is H state, BA3101
operates in clock master mode, SYNC outputs operating clock, otherwise
the operating mode is clock Slave mode, SYNC pin accept clock input.
Could be input or output clock to synchronize multiple class D devices.
Input/Output
I/O direction is decided by “MSTR/ SLV ” pin.
Input
Power
Power ground
Input/Output External resistor for current control
14
ROSC
15
VREG
Output
5V voltage regulation output for internal reference.
16
VBYP
Output
Bias reference voltage output, need connect an external capacitor.
17
GND
Power
Power ground
18
NC
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BA3101
10W Stereo Class D Audio Power Amplifier
19 ~ 20 LOUTP
Output
Left channel positive output
21 ~ 22 LOUTN
Output
Left channel negative output
24 ~ 25 GND
Power
Power ground
26 ~ 27 PVDDL
Power
Power supply for left channel output
28 ~ 29 PVSSL
Power
Power ground for left channel output
32 ~ 33 PVSSR
Power
Power ground for right channel output
34 ~ 35 PVDDR
Power
Power supply for right channel output
36 ~ 37 GND
Power
Power ground
39 ~ 40 ROUTN
Output
Right channel negative output
41 ~ 42 ROUTP
Output
Right channel negative output
23
NC
30 ~ 31 NC
38
NC
43
NC
44
SHUTDOWN_B
Input
45
MUTE
Input
46
FAULT
Output
47 ~ 48 VDD
Exposed Thermal
PAD
Power
Shutdown signal for IC (L state = disabled, H state= normal). TTL logic
levels with compliance to VDD.
Signal to instantly disable output; Signal is TTL logic level compatible and
compliance with VDD.
Fault status indicator. HIGH = short-circuit fault. LOW = fault-free. Only
reports short-circuit faults.
Power supply.
The thermal pad have to be soldered and be connect to the PCB large
ground copper area.
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BA3101
10W Stereo Class D Audio Power Amplifier
FUNCTIONAL BLOCK DIAGRAM
TEST SETUP FOR PERFORMANCE MEASUREMENTS
+
AP SYS-2722
(Analog Generator)
-
OUTP
INP
BA3101
Demo
Board OUTN
INN
+
Load
AP
AUX-0025
AP SYS-2722
-
(Analog Analyzer)
10uF
Power
Supply
Page 7 of 7
BA3101
10W Stereo Class D Audio Power Amplifier
Note: This connection diagram shows single channel configuration. All graphs were measured by BA3101 demo board. Two 22µH
inductors are used in series with load resistor to emulate the speaker for efficiency measurement.
TYPICAL CHARACTERISTICS
Table of Graphs
Figure No.
Description
1
THD+N vs. Output Power
Gain=20dB,Load=8Ω,VDD=12V
2
THD+N vs. Output Frequency
Gain=20dB,Load=8Ω,VDD=12V
3
Crosstalk vs. Frequency
4
Gain and Phase
5
Output Power vs. Supply Voltage
Gain=20dB,Load=8Ω
6
Output Power vs. Current
Gain=32dB,Load=8Ω
7
Efficiency
Gain=32dB,Load=8Ω,VDD=12V
Gain=20dB,Load=8Ω,VDD=12V,
THD+N=1%
Gain=32dB,Load=8Ω,VDD=12V,
CIN=10µF,VIN=0.1V
Important notice: Power above 10 W may require increased heatsinking.
Figure 1.
THD+N vs Output Power
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BA3101
10W Stereo Class D Audio Power Amplifier
Figure 2.
Figure 3.
THD+N vs Frequency
Crosstalk vs Frequency
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BA3101
10W Stereo Class D Audio Power Amplifier
Figure 4. Gain and Phase Shift vs Frequency
Figure 5. Output Power vs Supply
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BA3101
10W Stereo Class D Audio Power Amplifier
Figure 6. Supply Current vs Output Power
Figure 7. Efficiency
FUNCTION DESCRIPTION
Output Filter Application Note
Design the BA3101 without the filter if the traces from amplifier to speaker are short (< 10cm), where
the speaker is in the same enclosure as the amplifier is a typical application for class D without a filter.
Many applications require a ferrite bead filter. The ferrite filter reduces EMI around 30MHz. When
selecting a ferrite bead, choose one with high impedance at high frequencies, but low impedance at low
frequencies.
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BA3101
10W Stereo Class D Audio Power Amplifier
Use an LC output filter if there are low frequency (<1 MHz) EMI sensitive circuits and there are long
wires from the amplifier to the speaker.
Figure 8. Typical LC Output Filter, Speaker Impedance=8Ω
Figure 9. Typical Ferrite Chip Bead Output Filter, Speaker Impedance=8Ω
Inductors used in LC filters must be selected carefully. A significant change in inductance at the peak
output current of the BA3101 will cause increased distortion. The change of inductance at currents up to
the peak output current must be less than 0.1µH per amp to avoid this. Also note that smaller inductors
than 33µH may cause an increase in distortion above what is shown in preceding graphs of THD versus
frequency and output power. In all cases, avoid using inductors which value are less than 22µH.
Capacitors used in LC filters must also be selected carefully. A significant change in capacitance at
the peak output voltage of the BA3101 will cause increased distortion. LC filter capacitors should have DC
voltage ratings of at least twice the peak application voltage (the power supply voltage). In all cases, it is
strongly recommended using capacitors with good temperature ratings like X5R.
Output Snubbers
In Figure 11, the 470pF capacitors in series with 22Ω resistors from the outputs of the BA3101 to
switching snubbers. They smooth switching transitions and reduce overshoot and ringing. By doing so
they improve THD+N at lower power levels and they improve EMC by 2 to 4 dB at middle frequencies.
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BA3101
10W Stereo Class D Audio Power Amplifier
They increase quiescent current by 3mA to 11mA depending on power supply voltage.
Figure 10. Output Snubbers
Over-Heat Protection
Over-Heat protection on the BA3101 prevents damage to the device when the internal die junction
temperature exceeds 150°C. Once the die temperature exceeds the thermal set point, the device enters
the shutdown state and the outputs are disabled. The device will back to normal operation when die
temperature is reduced without external system interaction.
Output Short Protection
The BA3101 has output short circuit protection circuitry on the outputs that prevents damage to the
device during output-to-output short, output-to-GND short and output-to-VDD short. BA3101 enter the
shutdown state and the outputs are disabled when detects output short. This is a latched fault and must be
reset by cycling the voltage on SHUTDOWN pin or MUTE pin, or by cycling the power off and then back
on. This clears the short circuit flag and allows for normal operation if the short was removed. If the short
was not removed, the protection circuitry would active again.
Internal 5V reference
The VREG terminal (pin 15) is the output of an internally generated 5V supply, used for the oscillator,
preamplifier, and gain control circuitry. It is highly recommended to place a 10nF~100nF capacitor close to
the pin to keep the internal regulator stable. This regulated voltage should be used to connect GAIN0,
GAIN1, MSTR/ SLV , and MUTE terminals only. Do not use it to drive external circuitry.
Bypass Capacitor
The internal bias generator (VBYP) nominally provides a 1.25V bias for the preamplifier stages using
internally. The input coupling capacitors and this internal voltage reference allow the inputs to be biased
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BA3101
10W Stereo Class D Audio Power Amplifier
within the optimal common-mode range of the input preamplifiers. The value of the capacitor on the VBYP
terminal (pin 16) is critical related to amplifier performance. During power up or recovery from the
shutdown state, this capacitor determines the rate at which the amplifier starts up. Using a larger value of
VBYP capacitor can increase amplifier start-up time but should not exceed 10µF.
Selection of ROSC
The class D output switching frequency can be controlled by ROSC and COSC by the following equation:
f OUT =
1
2 × ROSC × C OSC
ROSC is an external resistance connected to pin 14 that is nominally 100kΩ. COSC is an internal
capacitor that is nominally equal to 18 pF. Variation over fabrication process and temperature can result in
a ±15% change in this capacitor value. For example, if ROSC is fixed at 100kΩ, the frequency from device
to device with this fixed resistance could vary from 300 kHz to 250 kHz including the variations of ROSC
resistor.
LOW-ESR Capacitors
Low-ESR capacitors are high recommended for this application. Generally a practical capacitor can
be modeled simply as a resistor in series with an ideal capacitor. The voltage drop across this unwanted
resistor can eliminate the effects of the ideal capacitor. Place low ESR capacitors on supply circuitry can
improve THD+N performance.
Decoupling Capacitors
BA3101 requires appropriate power decoupling to minimize the output total harmonic distortion (THD).
Power supply decoupling also prevents intrinsic oscillations for long lead lengths between the amplifier
and the speaker. The optimum decoupling is achieved by using two capacitors of different types that target
different types of noise on the power supply lines. For higher frequency spikes, or digital hash on the rail, a
good low ESR ceramic capacitor, for example 0.1µF to 10µF, placed as close as possible to PVDD_A
pins works best. For filtering lower frequency noise, a larger low ESR aluminum electrolytic capacitor of
220µF or greater placed near the audio power amplifier is also recommended. The 220µF capacitor also
serves as local storage capacitor for supplying current during heavy duty on the amplifier outputs. The
PVDD_A terminals provide the power to the output transistors, so a 220µF or larger capacitor should be
placed on each channel PVDD_A terminal. A 10µF ceramic capacitor on each VDD terminal is also
recommended.
Gain Settings
The gain of the BA3101 can be set by GAIN0 and GAIN1 pins. The gain ratios listed in Table are
implemented by changing the taps on the feedback resistors in the preamplifier stage. Since the gain
settings are controlled by ratios of input resistor and feedback resistor of the preamplifier, the gain ratio
may varies with different VDD supply. Note the amplifier gain ratio is obtained at 12V VDD supply.
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BA3101
10W Stereo Class D Audio Power Amplifier
Gain 1
Gain 0
Gain Ratio
1
1
36dB
1
0
32dB
0
1
26dB
0
0
20dB
Table 1. BA3101 Gain Ratio
Differential Input
The differential input stage of the amplifier can cancel any common-mode noise coupled from input
paths. To use the BA3101 with a differential signal source, connect the positive output of the audio source
to the INP input and the negative output from the audio source to the INN input. To use the BA3101 with a
single-ended signal source, ac ground the INP or INN input through a coupling capacitor equal in value to
the input capacitor on INN or INP and apply the audio source to either input. In single-ended input
configuration, the unused inputs should be ac grounded at the audio source instead of at the IC input for
better noise performance.
SHUTDOWN OPERATION
The BA3101 employs a shutdown mode of operation designed to reduce supply current to the
absolute minimum level during periods of nonuse for power conservation. This terminal should be held
high during normal operation when the amplifier is in normal operating. Pulling low causes the output
drivers shutdown and the amplifier to enter a low-current state. Do not leave it unconnected, because
there is no weakly pulling resistor inside the amplifier. Remember that to place the amplifier in the
shutdown state prior to removing the power supply voltage so that power-off pop noise can be eliminated.
MSTR/ SLV and SYNC Operation
The MSTR/ SLV and SYNC terminals can be used to synchronize the frequency of the class D
output switching. When the MSTR/ SLV terminal is high, the output switching frequency is determined by
the selection of the resistor connected to the ROSC terminal. The SYNC terminal becomes an output
in this mode, and the frequency of this output is also determined by the selection of the ROSC resistor.
This TTL compatible, push-pull output can be connected to another BA3101, configured in the slave mode.
The output switching is synchronized to avoid any beat frequencies that could occur in the audio band
when two class D amplifiers in the same system produces switching noises on VDD supply. When
MSTR/ SLV terminal is in low state, the output switching frequency is determined by the incoming square
wave on the SYNC input. The SYNC terminal becomes an input in this mode and accepts a TTL
compatible square wave from another BA3101 configured in the master mode or from an external GPIO. If
connecting to an external GPIO, recommended frequencies are 225 kHz to 325 kHz for proper device
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BA3101
10W Stereo Class D Audio Power Amplifier
operation.
SAMPLE APPLICATION CIRCUIT
Figure 11. Stereo Class D with Differential Inputs
Figure 12. Stereo Class D with Single-Ended Inputs
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BA3101
10W Stereo Class D Audio Power Amplifier
PACKAGE DIMENSION
TQFP-48-EP
Page 17 of 7
BA3101
10W Stereo Class D Audio Power Amplifier
CONTACT INFORMATION
Biforst Technology Inc.
3F-3, No.32, Tai Yuen St., Jubei City, Hsin-Chu, Taiwan, R.O.C.
Tel: 886-3-552-6521; Fax: 886-3-552-6558; Email: [email protected]
Revision History
Version
Date
Page
Description
0.2
2009.06.24
Preliminary Release
1.0
2009.08.01
Initial Release
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