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6-Channel Electronic Volume Controller IC PT2258
DESCRIPTION
PT2258 is a 6-Channel Electronic Volume Controller IC utilizing CMOS Technology specially designed
for the new generation of AV Multi-Channel Audio System. PT2258 provides an I2C Control Interface,
an attenuation range of 0 to -79dB at 1dB/step, low noise, and high channel separation. Housed in 20
pins, DIP or SOP, PT2258's pin assignments and application circuit are optimized for easy PCB Layout
and cost saving advantages.
FEATURES
· CMOS Technology
· Low Power Consumption
· Least External Components
· Attenuation Range: 0 to -79dB at 1dB/step
· Operating Voltage: 5 to 9 V
· Low Noise, S/N Ratio>100dB (A-weighting)
· High Channel Separation
· I2C Bus Control Interface
· Selectable Address
· 6-Channel Outputs
· Available in 20 pins, DIP or SOP
APPLICATIONS
· AV Surround Audio Equipment
· Car Audio
· Mini Compo
· Computer Multi-Media Speaker
· Other Audio Equipments
PT2258 V1.2 -1- July, 2005
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6-Channel Electronic Volume Controller IC PT2258
BLOCK DIAGRAM
IN1
1d B/ s t e p
+ OUT 1
10 dB /S t ep -
Ref
1d B/s te p
10 dB /S t ep +
- OUT 2
IN2
IN3
1d B/ s t e p
+
10 dB /S t ep - OUT 3
Ref
1d B/s te p
10 dB /S t ep +
- OUT 4
IN4
IN5
1d B/s te p
+
10 dB /S t ep - OUT 5
Ref
1d B/ s t e p
10 dB /S t ep +
- OUT 6
IN6
Vc c
COD E1
COD E2 C ontr ol unit Ref +
-
REF
DGN D SDA SCL GND
PT2258 V1.2 -2- July, 2005
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6-Channel Electronic Volume Controller IC PT2258
PIN CONFIGURATION
IN1 1 20 OUT 1
IN2 2 19 OUT 2
IN3 3 18 OUT 3
CODE 2 4 17 CODE 1
DGND 5 16 VCC
P T 2 25 8
SCL 6 15 REF
SDA 7 14 GND
IN4 8 13 OUT 4
IN5 9 12 OUT 5
IN6 10 11 OUT 6
PT2258 V1.2 -3- July, 2005
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6-Channel Electronic Volume Controller IC PT2258
PIN DESCRIPTION
Pin Name I/O Description Pin No.
Channel Input No. 1.
IN1 I 1
Connect a Capacitor to Audio Source
Channel Input No. 2
IN2 I 2
Connect a Capacitor to Audio Source
Channel Input No. 3
IN3 I 3
Connect a Capacitor to Audio Source
CODE2 - Refer to Address Code Section 4
DGND - Digital Ground 5
SCL I I2C Clock Input 6
SDA I I2C Data Input 7
Channel Input No. 4
IN4 I 8
Connect a Capacitor to Audio Source
Channel Input No. 5
IN5 I 9
Connect a Capacitor to Audio Source
Channel Input No. 6
IN6 I 10
Connect a Capacitor to Audio Source
Channel Output No. 6
OUT6 O 11
Connect a Capacitor to the Next Stage
Channel Output No. 5
OUT5 O 12
Connect a Capacitor to the Next Stage
Channel Output No. 4
OUT4 O 13
Connect a Capacitor to the Next Stage
GND - Ground 14 14
Reference Voltage= 1/2 Vcc
REF - 15
Connect a Capacitor to the Ground
VCC - Power Supply Input 16 16
CODE1 - Refer to the Address Code Section 17
Channel Output No. 3
OUT3 O 18
Connect a Capacitor to the Next Stage
Channel Output No. 2
OUT2 O 19
Connect a Capacitor to the Next Stage
Channel Output No. 1
OUT1 O 20
Connect a Capacitor to the Next Stage
PT2258 V1.2 -4- July, 2005
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6-Channel Electronic Volume Controller IC PT2258
FUNCTION DESCRIPTION
BUS INTERFACE
Data are transmitted to and from the microprocessor to the PT2258 via the SDA and SCL. The SDA
and SCL make up the BUS Interface. It should be noted that the pull-up resistors must be connected to
the positive supply voltage.
DATA VALIDITY
A data on the SDA Line is considered valid and stable only when the SCL Signal is in HIGH State. The
HIGH and LOW States of the SDA Line can only change when the SCL signal is LOW. Please refer to
the figure below.
D ATA
CLK
D a t a Lin e D a ta
S ta b le , C h a ng e
D a t a Va lid A llo w e d
START AND STOP CONDITIONS
A Start Condition is activated when
1. the SCL is set to HIGH and
2. SDA shifts from HIGH to LOW State.
The Stop Condition is activated when
1. SCL is set to HIGH and
2. SDA shifts from LOW to HIGH State.
Please refer to the timing diagram below.
CLK
DATA
Start Stop
BYTE FORMAT
Every byte transmitted to the SDA Line consists of 8 bits. Each byte must be followed by an
Acknowledge Bit. The MSB is transmitted first.
PT2258 V1.2 -5- July, 2005
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6-Channel Electronic Volume Controller IC PT2258
ACKNOWLEDGE
During the Acknowledge Clock Pulse, the master (µP) puts a resistive HIGH level on the SDA Line.
The peripheral (audio processor) that acknowledges has to pull-down (LOW) the SDA line during the
Acknowledge Clock Pulse so that the SDA Line is in a Stable Low State during this Clock Pulse.
Please refer to the diagram below.
The audio processor that has been addressed has to generate an Acknowledge after receiving each
byte, otherwise, the SDA Line will remain at the High Level during the ninth (9th) Clock Pulse. In this
case, the master transmitter can generate the STOP Information in order to abort the transfer.
CLK 1 2 3 4 7 8 9
DATA MSB
A cknowledgment
Start
from R eceiver
TRANSMISSION WITHOUT ACKNOWLEDGE
If you want to avoid the acknowledge detection of the audio processor, a simpler µP transmission may
be used. Wait one clock and do not check the slave acknowledge of this same clock then send the new
data. If you use this approach, there are greater chances of faulty operation as well as decrease in
noise immunity.
INTERFACE PROTOCOL
The interface protocol consists of the following:
· A Start bit
· A Chip Address Byte
· ACK=Acknowledge bit
· A Data byte
· A Stop bit
Please refer to the diagram below:
P T2258 A DD RE SS
MS B FIRS T B YTE LS B MS B LS B MS B LS B
S TA RT 1 0 0 0 1 0 0 0 A CK DATA A CK DATA A CK S TOP
DATA TRA NS MITTE D (N-BY TES + A CK NOW LE DGE )
Notes:
1. ACK=Acknowledge
2. Max. Clock Speed=100K Bits/s
PT2258 V1.2 -6- July, 2005
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6-Channel Electronic Volume Controller IC PT2258
PT2258 ADDRESS CODE
PT2258 Address Code depends on the state of CODE1 (Pin No.17) and CODE2 (Pin No.4).
If CODE1 or CODE2 is connected to Vcc, then CODE1 or CODE2 is set to "1". If CODE1 or CODE2 is
connected to the Ground, it is set to "0". Please refer to the information below:
Condition 1:
CODE1 CODE2
1 1
Then, PT2258 Address Code is 8 CH:
1 0 0 0 1 1 0 0
MSB LSB
Condition 2:
CODE1 CODE2
1 0
Then, PT2258 Address Code is 88 H:
1 0 0 0 1 0 0 0
MSB LSB
Condition 3:
CODE1 CODE2
0 1
Then, PT2258 Address Code is 84 H:
1 0 0 0 0 1 0 0
MSB LSB
Condition 4:
CODE1 CODE2
0 0
Then, PT2258 Address Code is 80H:
1 0 0 0 0 0 0 0
MSB LSB
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6-Channel Electronic Volume Controller IC PT2258
I2C BUS INTERFACE START TIME
After Power is turned ON, PT2258 needs to wait for a short time in order to insure stability. The waiting
time period for PT2258 to send I2C Bus Signal is at least 200ms. If the waiting time period is less than
200ms, I2C Control may fail. Please refer to the diagram below.
V
POWER ON
90% VDD
VDD
At least 200ms
SDA/SCL
PT2258 V1.2 -8- July, 2005
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6-Channel Electronic Volume Controller IC PT2258
PT2258 CONTROL SOFTWARE PROCEDURE
1. In order to ensure exact operation under any operating voltage, it is recommended an instruction to
clear the register "C0H" must be transmitted first. Please refer to the following diagram:
Start 1 0 0 0 1 0 0 0 Ack 1 1 0 0 0 0 0 0 Ack Stop
2258 Address Clear Register
2. The PT2258 function register does not have any default settings. After clearing the register, an initial
value must send in order to each register. If a register does has not been set, it is possible that no
sound will be output.
3. When adjusting the volume of PT2258, it is necessary to send a multiple of 10dB followed by a 1dB
code to the attenuator in sequence. If this sequence is not followed, or if only a 10dB or 1dB value is
sent, the IC may not operate normally. Please refer to the diagram below:
Volume setting -42dB
Start 1 0 0 0 1 0 0 0 Ack 1 1 0 1 0 1 0 0 ACK 1 1 1 0 0 0 1 0 Ack Stop
PT2258 Address -40dB -2dB
Start 1 0 0 0 1 0 0 0 Ack 1 1 1 0 0 0 1 0 Ack 1 1 0 1 0 1 0 0 ACK Stop
PT2258 Address -2dB -40dB
The two methods above are both acceptable.
Warning!! The following transmission method is not permitted.
Send only a 10dB attenuation value:
Start 1 0 0 0 1 0 0 0 Ack 1 1 0 1 0 1 0 0 ACK Stop
PT2258 Address -40dB
Send only a 10dB attenuation value:
Start 1 0 0 0 1 0 0 0 Ack 1 1 1 0 0 0 1 0 ACK Stop
PT2258 Address -2dB
Do not send a 10dB code without simultaneously with a 1dB code or in combination with other
instruction codes.
Start 1 0 0 0 1 0 0 0 Ack 1 1 1 0 0 0 1 0 Ack 1 1 1 1 1 0 0 1 ACK 1 1 0 1 0 1 0 0 ACK Stop
PT2258 Address -2dB All CH mute -40dB
PT2258 V1.2 -9- July, 2005
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6-Channel Electronic Volume Controller IC PT2258
DATA BYTES DESCRIPTION
FUNCTION BITS
MSB LSB FUNCTION
1 1 1 0 A3 A2 A1 A0 6-Channel, -1dB/step
1 1 0 1 0 B2 B1 B0 6-Channel, -10dB/step
0 0 0 1 A3 A2 A1 A0 Channel No. 3, -1dB/step
0 0 0 0 0 B2 B1 B0 Channel No. 3, -10dB/step
0 0 1 1 A3 A2 A1 A0 Channel No. 4, -1dB/step
0 0 1 0 0 B2 B1 B0 Channel No. 4, -10dB/step
0 1 0 1 A3 A2 A1 A0 Channel No. 2, -1dB/step
0 1 0 0 0 B2 B1 B0 Channel No. 2, -10dB/step
0 1 1 1 A3 A2 A1 A0 Channel No. 5, -1dB/step
0 1 1 0 0 B2 B1 B0 Channel No. 5, -10dB/step
1 0 0 1 A3 A2 A1 A0 Channel No. 1, -1dB/step
1 0 0 0 0 B2 B1 B0 Channel No. 1, -10dB/step
1 0 1 1 A3 A2 A1 A0 Channel No. 6, -1dB/step
1 0 1 0 0 B2 B1 B0 Channel No. 6, -10dB/step
6-Channel, Mute
1 1 1 1 1 0 0 M When M= 1, Mute On
When M=0, Mute Off
ATTENUATION UNIT BIT
A3/--- A2/B2 A1/B1 A0/B0 Attenuation Value(dB)
0 0 0 0 0/0
0 0 0 1 -1/-10
0 0 1 0 -2/-20
0 0 1 1 -3/-30
0 1 0 0 -4/-40
0 1 0 1 -5/-50
0 1 1 0 -6/-60
0 1 1 1 -7/-70
1 0 0 0 -8/-
1 0 0 1 -9/-
Note: Ax=-1dB/step, Bx=-10dB/step
PT2258 V1.2 - 10 - July, 2005
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6-Channel Electronic Volume Controller IC PT2258
ABSOLUTE MAXIMUM RATINGS
Parameter Symbol Ratings Unit
Supply Voltage Vs 12 V
Operation Temperature Topr -40+85
Storage Temperature Tstg -65+150
ELECTRICAL CHARACTERISTICS
(VDD=9V, VI=1Vrms, f=1KHz, Temp=27 )
Parameter Symbol Conditions Min. Typ. Max. Unit
Supply Voltage VDD 5 9 10 V
Supply Current Is 7 10 12 mA
Input Impedance RIN FL, FR, CTR, SUB, SL, SR 22 33 42 K
Max. Input Voltage VCL Volume=0dB, THD=1% - 2.8 3.0 Vrms
Channel Separation Sc 90 100 110 dB
Volume Control Range Crange - 79 - dB
Max. Attenuation Avmax - -79 - dB
Attenuation Step Astep - 1 - dB
Attenuation Error EA Volume=0-50dB -1.0 0 +1.0 dB
Mute Attenuation AMUTE A-weighting 90 95 98 dB
Total Harmonic
THD Volume=0dB, input 200mVrms 0.003 0.005 0.01 %
Distortion
Output Noise Noise A-weighting - 3 5 µV
Signal-Noise Ratio S/N 0dB=1Vrms, A-weighting 100 105 110 dB
Output Impedance Ro - 600 900
Output Gain Go -0.5 0 +0.5 dB
FL, FR, CENTER, SUB, SL, SR
Max. Output Voltage Vomax 2.3 2.5 2.8 Vrms
THD=1%
I2C Section
Bus Low Input Level VIL 0 2.4 2.5 V
Bus High Input Level VIH 2.8 3.0 VDD V
Bus Initialization TINIT Cref=10µF - 250 300 mS
PT2258 V1.2 - 11 - July, 2005
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6-Channel Electronic Volume Controller IC PT2258
APPLICATION CIRCUIT
INPUT 10 µ F 10 µ F OUT PUT
+ 1 IN1 OUT1 20 +
10 µ F 10 µ F
100K + 2 IN2 OUT 2 19 + 100K
10 µ F 10 µ F
100K + 3 IN3 OUT 3 18 + 100K
VC C
100K CODE2 CODE1 17 100K
4
+
5 DGND VCC 16 0.1 µ F 10 µ F
I 2C Bus
6 SCL REF 15 +
MCU Cref
7 SDA GND 14 10 µ F
10 µ F 10 µ F
+ IN4 OUT 4 13 +
8
10 µ F 10 µ F
100K + 9 IN5 OUT 5 12 + 100K
10 µ F 10 µ F
100K + 10 IN6 OUT6 11 + 100K
100K 100K
PT 2258
Address=88Hex
D G N D AG N D
PT2258 V1.2 - 12 - July, 2005
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6-Channel Electronic Volume Controller IC PT2258
ORDER INFORMATION
Valid Part Number Package Type Top Code
PT2258 20 Pins, DIP, 300mil PT2258
PT2258-S 20 Pins, SOP, 300mil PT2258-S
PT2258 (L) 20 Pins, DIP, 300mil PT2258
PT2258-S (L) 20 Pins, SOP, 300mil PT2258-S
Notes:
1. (L), (C) or (S) = Lead Free
2. The Lead Free mark is put in front of the date code.
PT2258 V1.2 - 13 - July, 2005
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6-Channel Electronic Volume Controller IC PT2258
PACKAGE INFORMATION
20 PINS, DIP, 300MIL
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6-Channel Electronic Volume Controller IC PT2258
Symbol Min. Nom. Max.
A - - 0.210
A1 0.015 - -
A2 0.115 0.130 0.195
b 0.014 0.018 0.022
b1 0.014 0.018 0.020
b2 0.045 0.060 0.070
b3 0.030 0.039 0.045
c 0.008 0.010 0.014
c1 0.008 0.010 0.011
D 0.980 1.030 1.060
D1 0.005 - -
E 0.300 0.310 0.325
E1 0.240 0.250 0.280
e - 0.100 bsc. -
eA - 0.300 bsc. -
eB - - 0.430
eC 0.000 - 0.060
L 0.115 0.130 0.150
Notes:
1. All dimensions are in INCHES.
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension "A", "A1" and "L" are measured with the package seated in JEDEC Seating Plane Gauge
GS-3
4. "D", "D1" and "E1" dimensions do not include mold flash or protrusions. Mold flash or protrusions
shall not exceed 0.010 inch.
5. "E" and "eA" measured with the leads constrained to be perpendicular to datum -c- .
6. "eB" and "eC" are measured at the lead tips with the leads unconstrained.
7. N is the number of the terminal positions (N=20)
8. Pointed or rounded lead tips are preferred to ease insertion.
9. "b2" and "b3" maximum dimensions are not include dambar protrusions. Dambar protrusions shall
not exceed 0.010 inch (0.25mm)
10. Distance between leads including dambar protrusions to be 0.005 inch minimum.
11. Datum plane -H- coincident with the bottom of lead, where lead exits body.
12. Refer to JEDEC MS-001, Variation AD.
JEDEC is the trademark of JEDEC SOLID STATE TECHNOLOGY ASSOCIATION.
PT2258 V1.2 - 15 - July, 2005
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6-Channel Electronic Volume Controller IC PT2258
20 PINS, SOP, 300MIL
Symbol Min. Nom. Max.
A 2.35 - 2.65
A1 0.10 - 0.30
B 0.33 - 0.51
C 0.23 - 0.32
D 12.60 - 13.00
E 7.40 - 7.60
e - 1.27 bsc. -
H 10.00 - 10.65
h 0.25 - 0.75
L 0.40 - 1.27
0 - 8
PT2258 V1.2 - 16 - July, 2005
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6-Channel Electronic Volume Controller IC PT2258
Notes:
1. Dimensioning and tolerancing per ANSI Y14.5M-1982.
2. Dimension "D" does not include mold flash, protrusions or gate burrs. Mold Flash, protrusion or gate
burrs shall not exceed 0.15 mm (0.006 in) per side.
3. Dimension "E" does not include interlead flash or protrusions. Interlead flash or protrusions shall not
exceed 0.25 mm (0.010 in) per side.
4. The chamfer on the body is optional. It is not present, a visual index feature must be located within
the crosshatched area.
5. "L" is the length of the terminal for soldering to a substrate.
6. N is the number of the terminal positions (N=20)
7. The lead width "B" as measured 0.36 mm (0.014 in) or greater above the seating plane, shall not
exceed a maximum value of 0.61 mm (0.24 in).
8. Controlling dimension: MILLIMETER.
9. Refer to JEDEC MS-013, Variation AC.
JEDEC is the trademark of JEDEC SOLID STATE TECHNOLOGY ASSOCIATION.
PT2258 V1.2 - 17 - July, 2005