Audio Accessory ICs for Mobile Devices
Voice/Audio
Mixer & Selector IC
BU7831KN
No.10087EAT02
●Description
BU7831KN is the sound path selector which include 3 stereo inputs, Stereo headphone amp, 600Ω driver amp, and
2stereooutputs. Each output have a mixer and an attenuator, you can set the variable audio path setting. The variable audio
source can connect to Headphone and speaker through this LSI.
●Feature
1) It has 3stereo inputs.
2) It has analog mixer on each input.
3) It matches for the application used the Headphone because it has 16Ω audio driver.
4) 16Ω driver has the pop-noise less function.
5) The attenuator of 16Ω driver has soft changing and muting function.
6) It has 600Ω driver for external output.
7) It included stereo output for stereo speaker.
8) VQFN20 small package
●Applications
It is for portable equipments with audio player.
●Absolute
maximum ratings
Parameter
Supply voltage
Power dissipation
Operating temperature range
Storage temperature range
*1
Reduce by 5.3 mW/
℃
over 25
℃
Symbol
VDD
Pd
Topr
Tstg
Ratings
-0.3½4.5
530
*1
-30½+85
-55½+125
Unit
V
mW
℃
℃
●Recommended
operating range
Parameter
Supply voltage
Symbol
VDD
Ratings
Min.
2.5
Typ.
3.0
Max.
3.3
Unit
V
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© 2010 ROHM Co., Ltd. All rights reserved.
1/16
2010.09 - Rev.A
BU7831KN
●Electric
Characteristics
Unless otherwise specified,
・Analog
Part
Parameter
Stand-by current
Operation current 1
Operation current 2
Technical Note
Ta=25
℃,AVDD=DVDD=3.0V
Symbol
Istb
Idd1
Idd2
Limits
Min.
-
-
-
-
-
-
2.0
2.0
Typ.
-
0.26
2.3
0.05
10
-94
-
-
Max.
3
0.42
3.7
0.5
-
-80
-
-
Unit
µA
mA
mA
%
mW
dBV
Vp-p
Vp-p
Conditions
Stand-by mode
BIAS part. No signal
ST1R, ST1L to HPR, HPL
Exclude Idd1, No signal
Vo=-10dBV, 20kHzL PF
THD=10%, RL=16Ω
JIS A weighting
THD≦1%, RL=10kΩ
THD≦1%, RL=600Ω
Total harmonic distortion 1 (HPL, HPR) THDhp1
Output power 1(HPL, HPR)
Output Noise Voltage 1 (HPL, HPR)
Maximum output level 1 (SPL, SPR)
Maximum output level 2 (EXTO)
・Digital
input (DC)
Parameter
Input L level voltage
Input H level voltage
Input current
・CPU
interface
Parameter
Cycle Time
Input Data Hold Time
Input Data Setup Time
Chip Select Setup Time
Chip Select Hold Time
Symbol
tcyc
tdh
tds
tcs
tch
Symbol
V
IL
V
IH
I
IN
PO1
V
NO
VO
MAX1
VO
MAX2
Limits
Min.
-
2.1
-
Typ.
-
-
-
Max.
0.7
-
±2
Unit
V
V
µA
Conditions
0V, 3V force
Limits
Min.
250
50
50
50
50
Typ.
-
-
-
-
-
Max.
-
-
-
-
-
Unit
ns
ns
ns
ns
ns
Conditions
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© 2010 ROHM Co., Ltd. All rights reserved.
2/16
2010.09 - Rev.A
BU7831KN
●Reference
Data (Unless otherwise specified, Ta=25
℃,AVDD=DVDD=3.0V)
1.0
CIRCUIT CURRENT : ICC(mA)
10
CIRCUIT CURRENT : ICC(mA)
10
Technical Note
STAND BY CURRENT : Ist(μA)
0.8
8
8
0.6
6
6
0.4
4
2
4
0.2
2
0.0
2.0
2.5
3.0
3.5
4.0
4.5
SUPPLY VOLTAGE : VDD(V)
0
2.0
2.5
3.0
3.5
4.0
4.5
SUPPLY VOLTAGE : VDD(V)
0
2.0
2.5
3.0
3.5
4.0
4.5
SUPPLY VOLTAGE : VDD(V)
Fig.1 Stand-by current
Fig.2 Operation current
At Headphone AMP part
100.00
100.00
Fig.3 Operation current
Of All blocks
100.00
1.00
1.00
EXTO : THD+N (%)
HPL : THD+N (%)
HPR : THD+N (%)
10.00
10.00
10.00
1.00
0.10
0.10
0.10
0.01
-100
-80
-60
-40
-20
0
INPUT LEVEL : VIN (dBV)
0.01
-100
-80
-60
-40
-20
0
INPUT LEVEL : VIN (dBV)
0.01
-100
-80
-60
-40
-20
0
INPUT LEVEL : VIN (dBV)
Fig.4 Total harmonic
Distortion (HPL)
100.00
100.00
Fig.5 Total Harmonic
Distortion (HPR)
20
0
Fig.6 Total Harmonic
Distortion (EXTO)
10.00
SPL : THD+N (%)
SPR : THD+N (%)
10.00
HPL : LINEARITY (dBV)
-80
-60
-40
-20
0
-20
-40
-60
-80
1.00
1.00
0.10
0.10
0.01
-100
-80
-60
-40
-20
0
INPUT LEVEL : VIN (dBV)
0.01
-100
INPUT LEVEL : VIN (dBV)
-100
-100
-80
-60
-40
-20
0
INPUT LEVEL : VIN (dBV)
Fig.7 Total Harmonic
Distortion (SPL)
20
0
HPR : LINEARITY (dBV)
-20
-40
-60
-80
-100
-100
-80
-60
-40
-20
0
INPUT LEVEL : VIN (dBV)
20
0
-20
-40
-60
-80
-100
-100
Fig.8 Total Harmonic
Distortion (SPR)
20
0
SPL : LINEARITY (dBV)
-20
-40
-60
-80
-100
-80
-60
-40
-20
0
-100
Fig.9 Linearity (HPL)
EXTO : LINEARITY (dBV)
-80
-60
-40
-20
0
INPUT LEVEL : VIN (dBV)
INPUT LEVEL : VIN (dBV)
Fig.10 Linearity (HPR)
Fig.11 Linearity (EXTO)
Fig.12 Linearity (SPL)
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© 2010 ROHM Co., Ltd. All rights reserved.
3/16
2010.09 - Rev.A
BU7831KN
20
0
SPR : LINEARITY (dBV)
Technical Note
-70
-75
-80
Noise [dBV]
Noise [dBV]
-70
-75
-80
-85
-90
-95
-100
-105
2.0
2.5
3.0
3.5
4.0
4.5
-110
2.0
2.5
3.0
3.5
4.0
4.5
SUPPLY VOLTAGE : VDD(V)
-20
-40
-60
-80
-100
-100
-80
-60
-40
-20
0
INPUT LEVEL : VIN (dBV)
-85
-90
-95
-100
-105
-110
SUPLLY VOLTAGE : VDD(V)
Fig.13 Linearity (SPR)
Fig.14 Output Noise (HPL)
Fig.15 Output Noise (HPR)
-70
-75
-80
Noise [dBV]
Noise [dBV]
-70
-75
-80
-70
-75
-80
Noise [dBV]
2.5
3.0
3.5
4.0
4.5
-85
-90
-95
-100
-105
-110
2.0
2.5
3.0
3.5
4.0
4.5
SUPLLY VOLTAGE : VDD(V)
-85
-90
-95
-100
-105
-110
2.0
SUPLLY VOLTAGE : VDD(V)
-85
-90
-95
-100
-105
-110
2.0
2.5
3.0
3.5
4.0
4.5
SUPLLY VOLTAGE : VDD(V)
Fig.16 Output Noise (EXTO)
Fig.17 Output Noise (SPL)
Fig.18 Output Noise (SPR)
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© 2010 ROHM Co., Ltd. All rights reserved.
4/16
2010.09 - Rev.A
BU7831KN
●Block
Diagram, Recommended application circuit, Pin assign
2.5½3.3V
Technical Note
+
VDD
VSS
ST1L
Other
Source
PCM
CODEC
ST2L
ST1R
ATT1L
0½
‐28dB
2dBstep
ATT1R
0½
‐28dB
2dBstep
ATT2L
0/
‐6dB
ST2R
ATT2R
0/
‐6dB
ST3L
ATT3L
MIXSEL
1
MIXSEL2
ATT4L
0½
‐28dB
2dBstep
－
＋
SPL
ATT4R
0½
‐28dB
2dBstep
－
＋
Stereo
Speaker
Amp
SPR
Stereo
Tuner
MIXSEL3
ATT5
0½
‐28dB
2dBstep
－
＋
External
600Ω
EXTO
MIXSEL4
ATT6L
0½
‐28dB
2dBstep
＋
－
16Ω
+
HPL
100 µF
StereoHeadPhone
Stereo
Melody
ST3R
0/
‐6dB
MIXSEL5
ATT6R
0½‐28dB
2dBstep
＋
－
16Ω
+
100 µF
ATT3R
0/
‐6dB
BIAS
HPR
Serial
Control
CVCOM
NRST SCLK SDATA NCS
CSTEP
CSTART
+
4.7 µF
1 µF
1 µF
RESET
CPU I/F
CPU
Fig.19 Application circuit example
VDD
15
VSS
14
HPR
13
CSTEP
12
CVCOM
11
HPL 16
10 ST3L
CSTART 17
9 ST3R
EXTO 18
BU7831KN
8 ST2L
SPR 19
7
ST2R
SPL 20
1
SCLK
2
SDATA
3
NCS
4
NRST
5
ST1R
6
ST1L
Fig.20 Pin Assign
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© 2010 ROHM Co., Ltd. All rights reserved.
5/16
2010.09 - Rev.A
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