YAC526
EVR3
Electric Variable Resistance 3
Outline
YAC526 (EVR3) is a 2ch high grade digital volume LSI for high-end audio systems.
Owing to its built-in high-quality sound operational amplifier, output with wide dynamic range and low distortion
factor can be obtained.
YAC526 is able to control each channel through a serial data interface in 255 steps at 0.5dB per step, and
daisy chain connection can constitute a multichannel system.
Owing to its zero-cross detection function, the device is able to suppress audible noise that may occur at a quick
volume change.
YAC526 CATALOG
CATALOG No.:LSI-4AC526A2
2003.10
Features
Built-in 2channel high sound quality operational amplifier.
Wide volume range.
31.5dB-95.0dB, MUTE (0.5dB/step, 255 steps)
Maximum input signal amplitude
4.2Vrms (6V power supply)
Low distortion (THD)
0.0002 typ. (Input=1Vrms@1kHz, Gain=0dB
Low residual noise
1.2Vrms typ. (Gain=MUTE, IHF-A)
Power supply voltage
4.75V6.6V
Silicon gate CMOS process.
24-pin plastic SSOP. The plating of pins is lead-free.(YAC526-EZ)
YAC526
Terminal configration
2
24 pin SSOP Top View
SCLK
SDATAO
TE1
DGND
REF
DVSS
AVDD
IN1
IN2
AVSS
1
2
3
4
5
6
7
8
9
10
11
12
SDATAI
CSN
ZCEN2
ZCEN1
OUT1
OUT2
24
23
22
21
20
19
18
17
16
15
14
13
I/O
No.
Name
Function
1
2
3
4
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
DVSS
TE2
TE3
ZCEN1
ZCEN2
CSN
SDATAI
5
Terminal function
I
Minus power supply for digital (-6.0V Typ.)
-
Test terminal (Pull-down) Non connection or connect to DGND terminal.
I
I
Chip select input
I
Serial data input
TE2
TE3
REF1A
REF1B
AVSS
AVDD
REF2A
REF2B
DGND
Digital ground
-
REF
O
SCLK
I
Serial clock input
SDATAO OD
I
I
Test terminal (Pull-down) Non connection or connect to DGND terminal.
Test terminal (Pull-down) Non connection or connect to DGND terminal.
TE1
I
AI
ch2 analog input The output impedance of input signal source is used less than 10k
.
IN2
REF2A
AI
ch2 analog reference voltage input A Connect to ground directly.
REF2B
AI
ch2 analog reference voltage input B Connect to ground directly.
OUT2
AO ch2 analog output
AVDD
Plus power supply for analog (+6.0V Typ.)
-
AVSS
Minus power supply for analog (-6.0V Typ.)
-
AVSS
Minus power supply for analog (-6.0V Typ.)
-
AVDD
Plus power supply for analog (+6.0V Typ.)
-
OUT1
AO ch1 analog output
REF1B
AI
ch1 analog reference voltage input B Connect to ground directly.
REF1A
AI
ch1 analog reference voltage input A Connect to ground directly.
AI
IN1
Note A: analog terminal, OD: Open drain output terminal, "L" level means V
IL
, "H" level means V
IH
.
Zero-cross control input 1. Select one from four types of zero-cross modes including non-zero-
changes at 1 second or more after the rise of CSN signal.
cross mode. When changing zero-cross modes during operation, set the system so that it
Zero-cross control input 2. Select one from four types of zero-cross modes including non-zero-
changes at 1 second or more after the rise of CSN signal.
cross mode. When changing zero-cross modes during operation, set the system so that it
Reference voltage output for digital For attaining stabilization, connect this terminal to
DVSS terminal through a capacitance of 10F or higher (C
REF
).
And please do not use this terminal output for the drive purpose of an external circuit.
Serial data output
Serial data are outputted from this terminal when CSN pin is "L" level. This terminal becomes
high-impedance state when CSN pin is "H". Since it is an open drain output pin, pull it up
connected. Do not allow output current of 1.5mA or over.
through a resistor to the power supply voltage (to be AVDD or less) of a device to be
When avoid the use of this terminal, connect to ground.
ch1 analog input The output impedance of input signal source is used less than 10k
.
When avoid the use of this terminal, connect to ground.
YAC526
3
Block diagram
IN1
REF1A
OUT1
0-95dB
0+31.5dB
OUT2
0-95dB
0+31.5dB
REF2A
IN2
Zero
Crossing
Detector
Zero
Crossing
Detector
Control
Register
S/P
Register
16
TE3
ZCEN1
ZCEN2
SDATAO(OpenDrain)
SDATAI
SCLK
CSN
AVSS
DGND
REF
AVDD
REF1B
REF2B
OPAmp
100
Vol
A:
15k
Vol
B:
10k
TE2
TE1
Vol
A:
15k
Vol
B:
10k
OPAmp
DVSS
100
YAC526
4
Description of functions
Analog functions
Maximum input voltage
The maximum amplitude of the input signal that is inputted to the analog input pin of YAC526 is 4.2Vrms when
power supply voltage is 6V.
For a system to which a signal exceeding the power supply voltage (AVDD/AVSS) may be applied, use
external diodes to suppress the signal to the maximum rating or less.
Maximum output voltage
The maximum output voltage(THD<1
) of the signal that is outputted from the analog output pin of YAC526 is
4.2Vrms when power supply voltage is 6V and no load is connected. The output impedance is 100
(typ.).
Realization of low residual noise system
General audio amplifiers are designed to have input sensitivity of approximately 150mV, and have a gain of
approximately 16dB at the preamplifier (PreAMP) section and approximately 30dB at the main amplifier section
(MainAMP).
The residual noise of YAC526 (Gain=MUTE) is 1.2 Vrms (typ.) which is very small, and the device has positive
side gain (max: 31.5dB). Therefore, by using YAC526 also as "PreAMP", systems with a very small residual noise
and amplification of volume control noise can be configured.
For conventional configurations that need a "PreAMP", even if the residual noise of the volume control itself is
zero, the noise that is produced at the "PreAMP" is amplified by the gain, the noise becomes very high when it is
heard at the speakers.
When the input converted noise of "PreAMP" is 1 V, the conventional configuration produces noise of
approximately 200
V at the speakers. For the configuration that uses YAC526, the noise is 38 V which is very
small.
1Vrms
6.3Vrms
200Vrms
Volume
PreAMP
MainAMP
+16dB
+30dB
YAC526
1.2Vrms
38Vrms
Volume + PreAMP
MainAMP
-+16dB
+30dB
Zin=10k
Residual noise produced by
conventional configuration
Residual noise produced by a
configuration that adopts YAC526
YAC526
5
Digital functions
Serial data interface
Writing of volume control data into YAC526 is performed through a serial interface. SDATAI is a serial data input
pin, SCLK is a clock input pin, and CSN is a chip select pin for writing the value of volume. 16-bit serial data that
is inputted from SDATAI (MSB first) is taken into YAC526 at the rising edge of SCLK when CSN terminal is at
"L" level. The serial data is latched at the rising edge of CSN, and volume value of each channel is set into the
register. The present volume value is outputted from SDATAO pin as serial data. With this data, the control by
using daisy chain connection and verification of the present volume value can be performed easily.
Note that the register value after turning the power supply on is ALL"0" (muted state) and the interface is
enabled after a predetermined period (t
PUP
) has elapsed. (Serial access is prohibited in t
PUP
period.)
CSN
SCLK
SDATAI
SDATAO
D1[15] D1[14] D1[13] D1[12] D1[11] D1[10]
D1[7]
D1[6]
D1[5]
D1[4]
D1[3]
D1[2]
D1[1]
D1[0]
D0[15] D0[14] D0[13] D0[12] D0[11] D0[10]
D0[7]
D0[6]
D0[5]
D0[4]
D0[3]
D0[2]
D0[1]
D0[0]
D1[15]
Assignment of volume control data
D[15:
8]
Channel1
Volume
data
D1[15:0]
is
volume
data
value
to
change.
D[
7:
0]
Channel2
Volume
data
D0[15:0]
is
present
volume
data
value.
Daisy chain
YAC526 is extensible to a multichannel system with daisy chain connection.
For example, by connecting the device with YAC523 (7ch digital volume) through daisy chain, 8.1ch system can
be attained. By connecting SDATAO pin of YAC526 (or YAC523) to SDATAI pin of YAC523 (or YAC526),
YAC526 and YAC523 can be controlled simultaneously without need of a complex addressing.
(It is also possible to connect multiple YAC526.)
The volume data is taken into S/P (serial / parallel) registers of each LSI by setting CSN pin to "L" for 8 clock
period on all channels that are connected with daisy chain. And, by setting CSN pin to "H" after the elapse of 8
clock period on all channels, the data is written from S/P registers of all YAC526 (or YAC523) that are connected
with daisy chain into the control registers simultaneously to change the volume value.
Example: Assignment of volume control data when a combination of YAC526 and YAC523 as described below
is used.
CSN
SCLK
SDATAI
D[71]
D[70]
D[69]
D[68]
D[67]
D[66]
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
D[71:64]
[YAC526]
Channel1
Volume
data
D[63:56]
[YAC526]
Channel2
Volume
data
D[55:48]
[YAC523]
Channel1
Volume
data
D[47:40]
[YAC523]
Channel2
Volume
data
D[39:32]
[YAC523]
Channel3
Volume
data
D[31:24]
[YAC523]
Channel4
Volume
data
D[23:16]
[YAC523]
Channel5
Volume
data
D[15:
8]
[YAC523]
Channel6
Volume
data
D[
7:
0]
[YAC523]
Channel7
Volume
data
CSN
SDATAI
SDATAO
SCLK
YAC523
OUT
IN
5V
5V
CSN
SDATAI
SDATAO
SCLK
YAC526
OUT
IN
2
7
2
7
Controller
Audio source
PDF 
ZIP