BL6110

BL6110
Features
Mono Class-D Audio Power Amplifier；
No LC filter for optional PWM output；
Minimum external component；
Internally Generated 250kHz Switching
Frequency；
Externally configurable gain；
Efficiency at 3.6V supply, 8Ω speaker：
400mW, 88%(typ)；
100mW, 80%(typ)；
Low Quiescent current ,2.5mA (typ)；
Low power S D N Mode, 0.3µA(typ)；
Wide supply voltage range: 2.5 ～5.5 V
Operating Voltage；
Excellent PSRR(-75dB)，Better CMRR
(-63dB)，High SNR( -99dB)；
Click-Pop Suppression Circuity/Short
-circuit/Thermal-Overload Protection；
Space-saving Packaging :Wafer Chip
Scale Packaging(WCSP)；
2.5W Filterless ClassClassD Audio Power Amplifier
Overview
The BL6110 is a 2.5-W high efficiency
filter-free class-D audio power amplifier
(class-D amp) in wafer chip scale package
(WCSP) that requires only three external
components. Features like 90% efficiency,
–75-dB PSRR, improved RF-rectification
immunity, and total PCB area small than 9
mm make the BL6110 class-D amp ideal for
cellular handsets. A fast start-up time of 1 ms
with minimal pop makes the BL6110 ideal for
PDA applications.
In cellular handsets, the earpiece, speaker
phone, and melody ringer can each be driven
by the BL6110. The BL6110 allows
independent gain while summing signals from
seperate sources, and has a low 40 µV noise
floor, A-weighted.
The structure of BL6110 include:
Preamplifier、PWM、FEEBACK、DRIVER、
Vref and Bias、Ramp and Clock、Protection
Logic 、 SDN and NMOS/PMOS Driver
Transistor and so on.
Application
Cellular Phones MP3 Players
PDA
Portable Audio
Portable Electronic Devices
Portable Computer
Cs
A1
A2
A3
INP
GND
VON
B1
B2
B3
VDD
PVDD
GND
C1
C2
C3
INN
SDN
VOP
Supply
Ri
INP
Differential
Audio Input
Signla
VON
BL6110
Ri
INN
VOP
SDN
SDN
GND
Typical Application
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Typical Package: 9-PUMP WCSP
-1Total 9 Pages
1/24/2008
2.5W Filterless ClassClassD Audio Power Amplifier
BL6110
1
Function Diagram
FEEDBACK
VOP
INP
MPW
Preamplifier
DRIVER
INN
VON
FEEDBACK
SDN
2
BIAS AND REF
RAMP AND CLOCK
Protect logic
PIN Description
PIN PUMP.
Name
C1
INN
I
Negative Differential Input.
A1
INP
I
Positive Differential Input.
B1
VDD
I
Analog Positive Supply. Range: 2.5 V – 5.5 V.
C3
VOP
O
Positive BTL Output.
A2,B3
GND
I
Analog Ground
A3
VON
O
Negative BTL Output.
C2
SD N
I
The device enters in S D N Mode when a low
level is applied on this pin. An internal
300 k resistor will force the device in
S D N mode if no signal is applied to this pin. It
also helps to save space and cost.
B2
PVDD
O
Power Analog Positive Supply. Range: 2.5 V –
5.5 V
3
PERFORMANCE
Type
Description
CHARACTERISTICS
Electrical Characteristics (TA=25℃
℃)
Parameter
Symb
ol
Test Condition
VOS output offset
voltage （measured
differentially）
http://www.belling.com.cn
VI=0,AV=2V/V,VDD=2.5V
Measure
Pin
Min
Typ
Max
Unit
1
15
mV
to5.5v
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1/24/2008
BL6110
PSRR
2.5W Filterless ClassClassD Audio Power Amplifier
VDD=2.5V to5.5V
-75
VDD=2.5V
-67
-56
dB
-49
dB
to5.5V,VIC=VDD/2 to
CMRR
0.5V,VIC=VDD/2 to
VDD-0.8V
IH High-level input
μA
90
VDD = 5.5 V, VI = 5.8 V
current
Low-level
IL
VDD = 5.5 V, VI =-0.3 V
5
μA
input current
I(Q) Quiescent
VDD = 5.5V, no load
3.0
VDD = 3.6V, no load
2.6
VDD = 2.5V, no load
2.2
3.2
mA
current
I(SD) Shutdown
V S D N =0.35V, VDD=2.5V
Current
to5.5V
rDS(on)Static
0.3
VDD = 2.5V
700
VDD = 3.6V
500
VDD = 5.5V
400
2.7
1.5
μA
mΩ
drain-source
on-state
resistance
V S D N =0.4V
Output impedance
in
>1
kΩ
S D N
f(SW) Switch
VDD=2.5V to5.5V
200
250
300
VDD=2.5V to5.5V
285k Ω
RI
300k Ω
RI
315k Ω
RI
kHz
frequency
Gain
Resistance
300
kΩ
from SDN to GND
Operating Characteristic（
（TA=25℃
℃,Gain=2V/V,RL=8Ω
Ω）
Parameter
PO Output
Meas
Symb
Test Condition
ol
ure
Min
Typ
Max
Unit
Pin
THD + N = 10%, f = 1
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VDD = 5V
-3Total 9 Pages
2.5
W
1/24/2008
BL6110
Power
kHz, RL = 4Ω
2.5W Filterless ClassClassD Audio Power Amplifier
VDD = 3.6V
1.3
VDD = 2.5V
0.52
VDD = 5V
2.08
VDD = 3.6V
1.06
VDD = 2.5V
0.42
VDD = 5V
1.45
VDD = 3.6V
0.73
VDD = 2.5V
0.33
VDD = 5V
1.19
VDD = 3.6V
0.59
VDD = 2.5V
0.26
THD + N = 1%, f = 1
kHz, RL = 4Ω
THD + N = 10%, f = 1
kHz, RL =8Ω
THD + N = 1%, f = 1
kHz, RL =8Ω
THD+N Total
V = 5 V, Po = 1 W, R L= 8Ω, f = 1 kHz
0.18%
harmonic
V = 3.6 V, Po = 0.5 W, RL = 8Ω, f = 1
0.19%
kHz
distortion plus
V = 2.5 V, Po = 200 mW, RL = 8Ω, f =
noise
KSVR
0.20%
1 kHz
f = 217 Hz,
Supply
ripple rejection
VDD=3.6V,Input AC
V = 200
grounded with Ci=2μF
(RIPPLE)
-70
dB
mVpp
ratio
SNR Signal to
VDD = 5 V, PO = 1 W, RL = 8Ω
noise ratio
Vn Output
VDD = 3.6 V, f = 20
No
Voltage noise
Hz to 20 kHz,Inputs
weighting
99
dB
48
μ
VRMS
ac-grounded with Ci =
2 µF
A weighting
36
f=217Hz
-63
CMRR
Common mode
VDD=3.6V,VIC=1VPP
dB
rejection ratio
ZI Input
142
150
158
kΩ
impedance
Start-up time
from
1
ms
S D N
VDD = 3.6 V
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-4Total 9 Pages
1/24/2008
2.5W Filterless ClassClassD Audio Power Amplifier
BL6110
TEST SET UP FOR GRAPHS
Ci
Audio
Input
Signal
Ri
INP
Ci
VON
BL6110
Ri
INN
VOP
VP
Power
Supply
Load
30kHz
Low
Pass
Filter
Measur
ement
Input
GND
4.7uF
NOTES：
1.Unless otherwise noted, C= 1uF and R= 150 kΩ. Thus, the gain setting is 2 V/V and the cutoff
frequency of the input high pass filter is set to 1 Hz. Input capacitors are shorted for CMRR
measurements.
2.To closely reproduce a real application case, all measurements are performed using the
following loads: R L = 8Ω means Load = 15 uH + 8 + 15u H
R L = 4Ω means Load = 15 uH + 4+ 15 uH
3.For Efficiency measurements, the optional 30 kHz filter is used. An RC low pass filter is
selected with (100Ω , 47 nF) on each PWM output.
4
Description Information
The basic structure of the BL6110 is composed of one analog preamplifier, Feedback, a pulse
width modulator, DRIVER, Ramp and Clock, Vref and Bias, Protection Logic and SDN. The first
stage is externally configurable with gain setting resistor R and the other stage is fixed. The load is
driven differentially through two output stages NMOS/PMOS.
The differential PWM output signal is a digital image of the analog audio input signal. The
human ear is a band pass filter regarding acoustic waveforms, the typical values of which are 20
Hz and 22kHz. Thus, the user will hear only the amplified audio input signal within the frequency
range. The switching frequency and its harmonics are fully filtered. The inductive parasitic
element of the loudspeaker helps to guarantee a superior distortion value.
The output PMOS and NMOS transistors of the amplifier have been designed to deliver the
output power of the specifications without clipping. The channel resistance (R dson ) of the
NMOS and PMOS transistors is typically 0.4.
Short –circuit、Thermal-Overload Protection、Power supply detecting is applied to protect
from the die damaging. When the temperature increase 150±10℃, The BL6110 is shutdown
automotive; When Power Supply is small than 1.9V, The BL6110 do stop work automotive. After
these protection is generated, the BL6110 need only 1ms to work normally resetting SDN.
The BL6110 features comprehensive click-and-pop suppression that eliminates audible
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-5Total 9 Pages
1/24/2008
BL6110
2.5W Filterless ClassClassD Audio Power Amplifier
transients on start-up and shutdown. While in shutdown, the H-bridge is in a high-impedance state.
During startup or power-up, the input amplifiers are muted and an internal loop sets the modulator
bias voltages to the correct levels, preventing clicks and pops when the H-bridge is subsequently
enabled. For 1ms following startup, a soft-start function gradually inmates the input amplifiers.
5
Application Information
BL6110 Filterless Operation
Traditional Class D amplifiers require an output filter to recover the audio signal from the
amplifier’s output. The filters add cost, increase the solution size of the amplifier, and can
decrease efficiency and THD+N performance. The traditional PWM scheme uses large differential
output swings (2 x V DD peak-to-peak) and causes large ripple currents. Any parasitic resistance
in the filter components results in a loss of power, lowering the efficiency.
The BL6110 does not require an output filter. The device relies on the inherent inductance of
the speaker coil and the natural filtering of both the speaker and the human ear to recover the
audio component of the square-wave output. Eliminating the output filter results in a smaller, less
costly, more efficient solution. Because the frequency of the BL6110 output is well beyond the
bandwidth of most speakers, voice coil movement due to the square-wave frequency is very small.
Although this movement is small, a speaker not designed to handle the additional power can be
damaged. For optimum results, use a speaker with a series inductance >10µH. Typical 8Ω
speakers exhibit series inductances in the 20µH to 100µH range.
Voltage Gain
The first stage is an analog Preamplifier. The second stage is a PWM: the output of the first
stage is compared with a periodic Ramp signal. The output PWM gives a pulse width modulation
signal (PWM). The third and last stage is the direct conversion of the PWM signal with MOS
transistors H bridge into a powerful output signal with low impedance capability.
With an 8Ω load, the total gain of the device is typically set to:
300K Ω
Ri
Input Capacitor Selection (Ci )
An input capacitor( Ci) in conjunction with the input resistance(Ri) of the BL6110 forms a
highpass filter that removes the DC bias from an incoming signal. The AC coupling capacitor
allows the amplifier to bias the signal to an optimum DC level. Assuming zero source impedance,
the -3dB point of the highpass filter is given by:
FC =
1
2 × π × Ri × Ci
Choose Ci so f -3dB is well below the lowest frequency of interest. Setting f-3dB too high affects
the low frequency response of the amplifier. Use capacitors whose dielectrics have low-voltage
coefficients, such as tantalum or aluminum electrolytic. Capacitors with high-voltage coefficients,
such as ceramics, may result in increased distortion at low frequencies. If a ceramic capacitor is
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-6Total 9 Pages
1/24/2008
2.5W Filterless ClassClassD Audio Power Amplifier
BL6110
selected due to size constraints, use the largest package possible to minimize voltage coefficient
effects.
DC-Coupled Input
The input amplifier can accept DC-coupled inputs that are biased within the amplifier’s
common-mode range. DC coupling eliminates the input-coupling capacitors, reducing component
count to potentially one external component. However, the low-frequency rejection of the
capacitors is lost, allowing low-frequency signals to feed through to the load.
Cs
Supply
Ri
INP
Differential
Audio Input
Signla
VON
BL6110
Ri
INN
VOP
SDN
SDN
GND
BL6110 DC-Coupled Input
Differential Input
The BL6110 features a differential input structure, making it compatible with many CODECs,
and offering improved noise immunity over a single-ended input amplifier. In devices such as
cellular phones, high-frequency signals from the RF transmitter can be picked up by the
amplifier’s input traces. The signals appear at the amplifier’s inputs as common-mode noise. A
differential input amplifier amplifies the difference of the two inputs; any signal common to both
inputs is canceled.
Cs
S u pp l y
Ci
Ri
IN P
D i ff e r en t ia l
A u di o In p u t
S i gn l a
Ci
VO N
BL6110
Ri
INN
VO P
SD N
SD N
GND
BL6110 Differential Input
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-7Total 9 Pages
1/24/2008
BL6110
2.5W Filterless ClassClassD Audio Power Amplifier
Single-Ended Input
The BL6110 can be configured as a single-ended input amplifier by capacitively coupling
either input to GND and driving the other input. Note that the single-ended voltage range of the
BL6110 is small. This limits the achievable output power for this device. Use higher gain versions
if higher output power is desired in a single-ended application.
Cs
Supply
Ci
Ri
INP
Single-Ended
Audio Input
Signla
Ci
VON
BL6110
Ri
INN
VOP
SDN
SDN
GND
BL6110 Single-Ended Input
6
PCB Application Layout
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-8Total 9 Pages
1/24/2008
BL6110
7
2.5W Filterless ClassClassD Audio Power Amplifier
Package
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-9Total 9 Pages
1/24/2008