查询SSM2250RM-R2供应商
Mono 1.5 W/Stereo 250 mW
FEATURES
Part of SoundMAX® audio solution for desktop computers
Mono 1.5 W differential or stereo 250 mW output
Single-supply operation: 2.7 V to 6 V
Low shutdown current = 60 μA
PC99 compliant
Low distortion: 0.2% THD at 1.5 W
Wide bandwidth: 4 MHz
Unity-gain stable
APPLICATIONS
Desktop, portable, and palmtop computers
Sound cards
Communication headsets
2-way communications
Hand-held games
GENERAL DESCRIPTION
The SSM2250 is intended for use in desktop computers that
have basic audio functions. It is also ideal for any audio system
that needs to provide both an internal monaural speaker and
a stereo line or headphone output. Combined with an AC97
codec, it provides a PC audio system that meets the PC99
requirements. The SSM2250 is compact and requires a minimum of external components.
The SSM2250 features an audio amplifier capable of delivering
1.5 W of low distortion power into a mono 4 Ω bridge-tied load
(BTL) or 2 × 90 mW into stereo 32 Ω single-ended load (SE)
headphones. Both amplifiers provide rail-to-rail outputs for
maximum dynamic range from a single supply. The balanced
output provides maximum output from a 5 V supply and
eliminates the need for a coupling capacitor.
The SSM2250 can automatically switch between an internal
mono speaker and external headphones. The device can run
from a single supply, ranging from 2.7 V to 6 V, with an active
supply current of 9 mA typical. The ability to shut down the
amplifiers (60 μA shutdown current) makes the SSM2250 an
ideal speaker amplifier for battery-powered applications.
LEFT IN
BYPASS CAP
RIGHT IN
V
G
N
Power Amplifier
SSM2250
PIN CONFIGURATIONS
1
LEFT IN
SE/BTL 3
GND 4
2
SSM2250
TOP VIEW
(Not to Scale)
SHUTDOWN
RIGHT IN 5
Figure 1. 10-Lead MSOP Pin Configuration
(RM Suffix)
114
NC
LEFT IN
SHUTDOWN
SE/BTL
+GND
RIGHT IN
SSM2250
78
NC
NC = NO CONNECT
Figure 2. 14-Lead TSSOP Pin Configuration
(RU Suffix)
FUNCTIONAL BLOCK DIAGRAM
A1
A3
CLICK AND POP
DD
REDUCTION
D
BIAS
Figure 3.
SWITCHING
CIRCUITRY
10
LEFT OUT/BTL–
9
V
DD
BTL+
8
7
BYPASS
6
RIGHT OUT
NC
LEFT OUT/BTL
V
DD
BTL+
BYPASS
RIGHT OUT
NC
A2
V
DD
-001
00359-002
LEFT SE/
MONO BTL
OUT–
MONO BTL
OUT+
V
DD
RIGHT
SE OUT
BTL/SE
SELECT
SHUTDOWN
00359-003
The SSM2250 is specified over the industrial (−40°C to +85°C)
temperature range. It is available in a 14-lead TSSOP and a
10-lead, surface mount MSOP package.
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 © 2005 Analog Devices, Inc. All rights reserved.
SSM2250
TABLE OF CONTENTS
Features .............................................................................................. 1
Electrical Characteristics, V
= 2.7 V..........................................3
S
Applications....................................................................................... 1
General Description ......................................................................... 1
Pin Configurations ........................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Electrical Characteristics, V
= 5.0 V......................................... 3
S
REVISION HISTORY
6/05—Rev. 0 to Rev. A
Updated Format..................................................................Universal
Updated Ordering Guide............................................................... 12
10/99—Revision 0: Initial Version
Absolute Maximum Ratings ............................................................4
ESD Caution...................................................................................4
Typical Perfor m a n c e Characte r i stics ..............................................5
Product Overview .............................................................................7
Typical Application .......................................................................7
Outline Dimensions ....................................................................... 12
Ordering Guide .......................................................................... 12
Rev. A | Page 2 of 12
SSM2250
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS, VS = 5.0 V
VS = 5.0 V, VCM = 2.5 V, TA = 25°C, unless otherwise noted.
Table 1.
Parameter Symbol Conditions Min Typ Max Unit
DEVICE CHARACTERISTICS
Output Offset Voltage V
Large Signal Voltage Gain A
Output Power P
OS
VO
OUT
BTL mode: RL = 8 Ω, THD < 1% 1,000 mW
Output Impedance Z
OUT
SHUTDOWN INPUT
Input Voltage High V
Input Voltage Low V
IH
IL
POWER SUPPLY
Supply Current I
S
SE mode 6.4 mA
Supply Current/Amplifier I
S
DYNAMIC PERFORMANCE
Slew Rate SR RL = 100 kΩ, CL = 50 pF 4 V/μs
Gain Bandwidth Product GBP 4 MHz
Phase Margin Фo 84 Degrees
NOISE PERFORMANCE
Voltage Noise Density e
n
BTL mode; AV = 2; BTL+ to BTL− 4 100 mV
RL = 2 kΩ 2 V/mV
SE mode: RL = 32 Ω, THD < 1% 90 mW
0.1 Ω
IS < 100 μA 2.0 V
IS > 1 mA 0.8 V
BTL mode 6.4 mA
60 μA
f = 1 kHz 45 nV/√Hz
ELECTRICAL CHARACTERISTICS, VS = 2.7 V
VS = 2.7 V, VCM = 1.35 V, TA = 25°C, unless otherwise noted.
Table 2.
Parameter Symbol Conditions Min Typ Max Unit
DEVICE CHARACTERISTICS
Output Offset Voltage V
Large Signal Voltage Gain A
Output Power P
OS
VO
OUT
BTL mode: RL = 8 Ω, THD < 1% 300 mW
Output Impedance Z
OUT
SHUTDOWN INPUT
Input Voltage High V
Input Voltage Low V
IH
IL
POWER SUPPLY
Supply Current I
S
SE mode 6.4 mA
Supply Current/Amplifier I
S
DYNAMIC PERFORMANCE
Slew Rate SR RL = 100 kΩ, CL = 50 pF 4 V/μs
Gain Bandwidth Product GBP 4 MHz
Phase Margin Фo 84 Degrees
NOISE PERFORMANCE
Voltage Noise Density e
n
BTL mode; AV = 2; BTL+ to BTL− 4 100 mV
RL = 2 kΩ 2 V/mV
SE mode: RL = 32 Ω, THD < 1% 25 mW
0.1 Ω
IS < 100 μA 2.0 V
IS > 1 mA 0.8 V
BTL mode 6.4 mA
32 μA
f = 1 kHz 45 nV/√Hz
Rev. A | Page 3 of 12
SSM2250
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Supply Voltage 6 V
Differential Input Voltage
1
±5 V
Common-Mode Input Voltage ±6 V
ESD Susceptibility 2000 V
Storage Temperature Range
All Packages −65°C to +150°C
Operating Temperature Range
All Packages −40°C to +85°C
Junction Temperature Range
All Packages −65°C to +165°C
Lead Temperature Range (Soldering, 60 sec) 300°C
1
Differential input voltage or ±VS, whichever is lower.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Stresses above those indicated under Absolute Maximum
Ratings may cause permanent damage to the device. This is a
stress rating only; functional operation of the device at these or
any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Table 4.
Package Type θ
1
JA
θ
JC
Unit
10-Lead MSOP (RM) 200 44 °C/W
14-Lead TSSOP (RU) 180 35 °C/W
1
θJA is specified for worst-case conditions; that is, θJA is specified for the device
soldered in circuit board for surface mount packages.
Rev. A | Page 4 of 12
SSM2250
TYPICAL PERFORMANCE CHARACTERISTICS
10
VS = 5V
BTL MODE
= 8Ω
R
L
= 1μF
C
B
= 1W
P
OUT
= 2
A
V
1
VS = 5V
SE MODE
RL = 32Ω
C
= 1μF
B
P
= 60mW
OUT
A
= 1
V
1
TOTAL HARMONIC DISTORTION (%)
0.1
20 20k100 1k 10k
FREQUENCY (Hz)
Figure 4. BTL Out THD + N vs. Frequency
10
VS = 2.7V
BTL MODE
= 8Ω
R
L
C
= 1μF
B
= 0.25W
P
OUT
= 2
A
V
1
TOTAL HARMONIC DISTORTION (%)
0.1
20 20k100 1k 10k
FREQUENCY (Hz)
Figure 5. BTL Out THD + N vs. Frequency
00359-004
00359-005
0.1
TOTAL HARMONIC DISTORTION (–%)
0.01
20 20k100 1k 10k
FREQUENCY (Hz)
Figure 7. SE Out THD + N vs. Frequency
1
VS= 2.7V
SE MODE
= 32Ω
R
L
= 1μF
C
B
= 15mW
P
OUT
= 1
A
V
0.1
TOTAL HARMONIC DISTORTION (%)
0.01
20 20k100 1k 10k
20 20k100 1k 10k
FREQUENCY (Hz)
FREQUENCY
Figure 8. SE Out THD + N vs. Frequency
00359-007
00359-008
10
VS = VARIES
BTL MODE
R
= 8Ω
L
C
= 1μF
B
V
= 1kHz
IN
A
= 2
V
1
TOTAL HARMONIC DISTORTION (%)
0.1
10m 2100m 1
OUTPUT POWER (W)
Figure 6. THD + N vs. Output Power
2.7V
3.3V
5.0V
00359-006
Rev. A | Page 5 of 12
TOTAL HARMONIC DISTORTION (%)
10
SE MODE
= 32Ω
R
L
= 1μF
C
B
= 1kHz
V
IN
1
0.1
0.01
10 200100
2.7V
3.3V
OUTPUT POWER (mW)
Figure 9. BTL Out THD + N vs. Output Power
5V
00359-009
SSM2250
10
1
VS = 5V
BTL MODE
= 8Ω
R
L
= 1μF
C
B
= 20Hz
V
IN
= 2
A
V
10
0.1
1
VS = 5V
SE MODE
= 32Ω
R
L
= 1μF
C
B
= 20Hz
V
IN
= 1
A
V
TOTAL HARMONIC DISTORTION (%)
0.1
10m 2100m 1
OUTPUT POWER (W)
Figure 10. BTL Out THD + N vs. Output Power at 20 Hz
10
VS = 5V
BTL MODE
= 8Ω
R
L
= 1μF
C
B
= 20kHz
V
IN
= 2
A
V
1
TOTAL HARMONIC DISTORTION (%)
0.1
10m 2100m 1
OUTPUT POWER (mW)
Figure 11. BTL Out THD + N vs. Output Power at 20 kHz
00359-010
00359-011
TOTAL HARMONIC DISTORTION (%)
0.01
10 200100
OUTPUT POWER (W)
Figure 12. SE Out THD + N vs. Output Power at 20 Hz
10
VS = 5V
SE MODE
= 8Ω
R
L
= 1μF
C
B
= 20kHz
V
IN
= 1
A
V
1
0.1
TOTAL HARMONIC DISTORTION (%)
0.01
10 200100
OUTPUT POWER (mW)
Figure 13. SE Out THD + N vs. Output Power at 20 kHz
00359-012
00359-013
Rev. A | Page 6 of 12
SSM2250
PRODUCT OVERVIEW
The SSM2250 is a low distortion power amplifier that can
drive a set of stereo headphones or a single 8 Ω loudspeaker. It
contains three rail-to-rail output op amps, click-and-pop reduction biasing, and all necessary switching circuitry. In SE (singleended) mode, the device automatically mutes the internal 8 Ω
speaker. In BTL (bridge-tied load) mode, the internal speaker
is activated.
In BTL mode, the SSM2250 can achieve 1 W continuous output
into 8 Ω at ambient temperatures up to 40°C. The power
derating curve shown in
proper operation at higher ambient temperatures. For a
standard 14-lead TSSOP package, typical junction-to-ambient
temperature thermal resistance (θ
board and 140°C/W on a 4-layer board.
Figure 17 should be observed for
) is 180°C/W on a 2-layer
JA
The SSM2250 can operate from a 2.7 V to a 5.5 V single supply.
The rail-to-rail outputs can be driven to within 400 mV of
either supply rail while supplying a sustained output current
of 350 mA into 8 Ω. The device is unity-gain stable and requires
no external compensation capacitors. The SSM2250 can be
configured for gains of up to 40 dB.
TYPICAL APPLICATION
In SE mode, the device operates similarly to a high current
output, dual op amp. A1 and A3 are independent amplifiers
with a gain of −R2/R1. The outputs of A1 and A3 are used to
drive the external headphones plugged into the headphone jack.
Amplifier A2 is shut down to a high output impedance state.
This prevents current from flowing through the 8 Ω internal
speaker, thereby muting it.
Although the gains of A1 and A3 can be set independently,
it is recommended that the feedback and feedforward resistor
around both amplifiers be equal. This prevents one channel
from becoming louder than the other.
In BTL mode, the current into the right in pin is directed to the
input of A1. This effectively sums the left in and right in audio
signals. The A2 amplifier is activated and configured with a
fixed gain of A
figuration that drives the internal speaker. Because the BTL
output voltages swing opposite to each other, the gain to the
speaker in BTL mode is twice the gain of SE mode. The voltage
across the internal speaker can be written
SPEAKER
The bridged output configuration offers the advantage of a
more efficient power transfer from the input to the speaker.
Because both outputs are symmetric, the dc voltage bias across
the 8 Ω internal speaker is 0. This eliminates the need for a
coupling capacitor at the output. In BTL mode, the A3 amplifier
is shut down to conserve power.
= −1. This produces a balanced output con-
V
2
()
VVV
RIGHTLEFT
R
(1)
××+=
2
1
R
Internal Speaker/External Headphones Automatic
Switching
Pin 4 on the SSM2250 controls the switching between the BTL
mode and the SE mode. Logic low to Pin 4 activates BTL mode,
while logic high activates SE mode. The configuration shown in
Figure 14 provides the appropriate logic voltages to Pin 4,
muting the internal speaker when headphones are plugged into
the jack.
A stereo headphone jack with a normalizing pin is required for
the application. With no plug inserted, a mechanical spring
connects the normalizing pin to the output pin in the jack.
Once a plug is inserted, this connection is broken.
Figure 14, Pin 4 of the SSM2250 is connected to the nor-
In
malizing pin for the right channel output. This pin, located in
the headphone jack, hits the ring on the headphone plug. A
100 kΩ pull-up resistor to 5 V is also connected at this point.
With a headphone plug inserted, the normalizing pin disconnects from the output pin, and Pin 4 is pulled up to 5 V,
activating SE mode on the SSM2250. This mutes the internal
speaker while driving the stereo headphones.
Once the headphone plug is removed, the normalizing pin
connects to the output pin. This drives the voltage at Pin 4
to 50 mV, as this point is pulled low by the 1 kΩ resistor now
connected to the node. The SSM2250 goes into BTL mode,
deactivating the right SE amplifier to prevent the occurrence
of any false mode switching.
It is important to connect Pin 4 and the 100 kΩ pull-up resistor
to the normalizing pin for the right output in the headphone
jack. Connecting them to the left output normalizing pin results
in improper operation from the device. The normalizing pin to
the left output in the headphone jack should be left open.
Coupling Capacitors
Output coupling capacitors are not required to drive the
internal speaker from the BTL outputs. However, coupling
capacitors are required between the amplifier’s SE outputs and
the headphone jack to drive external headphones. This prevents
dc current from flowing through the headphone speakers,
whose resistances are typically about 80 Ω.
Rev. A | Page 7 of 12
SSM2250
S
R2
20kΩ
R1
NC NC
LEFT IN
HUTDOWN
RIGHT IN
1μF
1μF
20kΩ
R1
20kΩ
NC
2
3
SSM2250
4
5
6
7
20kΩ
NC = NO CONNECT
Figure 14. Typical Application
The output coupling capacitor creates a high-pass filter with a
cutoff frequency of
1
=
f
−
3
dB
π
2
(2)
CR
L
C
where:
R
is the resistance of the headphone.
L
C
is the output coupling capacitor.
C
Although a majority of headphones have approximately 80 Ω of
resistance, the resistance can vary between models and manufacturers. Headphone resistances are commonly between 32 Ω
to 600 Ω. Using a 220 μF capacitor, as shown in
Figure 14, the
worst-case −3 dB corner frequency would be 22 Hz, with a 32 Ω
headphone load. Smaller output capacitors could be used at the
expense of low frequency response to the headphones.
An input coupling capacitor should be used to remove dc bias
from the inputs to the SSM2250. Again, the input coupling
capacitor in combination with the input resistor creates a highpass filter with a corner frequency of
1
=
f
3
dB
−
Using the values shown in
(3)
112
CR
π
Figure 14, where R1 = 20 kΩ and
C1 = 1 μF, creates a corner frequency of 8 Hz. This is acceptable,
as the PC99 audio requirement specifies the computer audio
system bandwidth to be 20 Hz to 20 kHz.
Pin 10 on the SSM2250 provides the proper bias voltage for
the amplifiers. A 0.1 μF capacitor should be connected here to
reduce sensitivity to noise on the power supply. A larger capacitor can be used if more rejection from power supply noise is
required.
141
13
12
11
10
9
8
NC
R2
5V
10μF
–
+
220μF
+
5V
220μF
+
BTL
OUT
100kΩ
1kΩ
1kΩ
NC
00359-014
The SSM2250 has excellent phase margin and is stable even
under heavy loading. Therefore, a feedback capacitor in parallel
with R2 is not required, as it is in some competitors’ products.
Power Dissipation
An important advantage in using a bridged output configuration is that bridged output amplifiers are more efficient than
single-ended amplifiers in delivering power to a load.
1.50
VDD = 5V
1.25
1.00
0.75
0.50
POWER DISSIPATION (W)
0.25
0
0 0.750.500.25 1.00 1.25 1.50
RL = 16Ω
OUTPUT POWER (W)
Figure 15. Power Dissipation vs. Output Power in BTL Mode
2
V
2
P
MAX,DISS
DD
=
(4)
2
R
π
L
Using Equation 4 and the power derating curve in
RL = 4Ω
RL = 8Ω
00359-015
Figure 17,
the maximum ambient temperature can be easily found. This
ensures that the SSM2250 does not exceed its maximum
junction temperature of 150°C.
The power dissipation for a single-ended output application
where an output coupling capacitor is used is shown in
Figure 16.
Rev. A | Page 8 of 12
SSM2250
0.35
VDD = 5V
0.3
0.25
0.2
0.15
0.1
POWER DISSIPATION (W)
0.05
0
0 0.30.20.1 0.4
Figure 16. Power Dissipation vs. Single-Ended Output Power (V
RL = 16Ω
RL = 8Ω
OUTPUT POWER (W)
RL = 4Ω
= 5 V)
DD
00359-016
The maximum power dissipation for a single-ended output is
2
V
P
MAXDISS
,
DD
=
2π
(5)
2
R
L
Because the SSM2250 is designed to drive two single-ended
loads simultaneously, the worst-case maximum power
dissipation in SE mode is twice the value of Equation 5.
A thorough mathematical explanation behind Equation 4 and
Equation 5 is provided in the SSM2211 data sheet.
Example
Given worst-case stereo headphone loads of 32 Ω, the maximum power dissipation of the SSM2250 in SE mode with a 5 V
supply is
2
()
V
P
,
MAXDISS
5
=
2
79
=
322
Ωπ
(6)
mW
Solving for Maximum Ambient Temperature
To protect the SSM2250 against thermal damage, the junction
temperature of the die should not exceed 150°C. The maximum
allowable ambient temperature of the application can be easily
found by solving for the expected maximum power dissipation
in Equation 4 and Equation 5, and using Equation 8.
Continuing from the previous example, the θ
of the SSM2250
JA
14-lead TSSOP package on a 4-layer board is 140°C/W. To
ensure that the SSM2250 die junction temperature stays below
150°C, the maximum ambient temperature can be solved using
Equation 8.
o
150
o
C
61
+=
PCT
×θ−+=
MAXDISSJAMAXAMB
,,
oo
(
×−+=
)
WWCC
633.0/140150
(8)
The maximum ambient temperature must remain below 61°C
to protect the device against thermal damage.
Another method for finding the maximum allowable ambient
temperature is to use the power derating curve in
Figure 17.
The y-axis corresponds to the expected maximum power
dissipation, and the x-axis is the corresponding maximum
ambient temperature. Either method returns the same answer.
1.0
14-LEAD TSSOP
0.8
θ
JA
10-LEAD MSOP
0.6
θ
JA
0.4
= 140°C/W
= 180°C/W
T
= 150°C/W
JMAX
FREE AIR
NO HEAT SINK
With an 8 Ω internal speaker attached, the maximum power
dissipation in BTL mode is (from Equation 4)
2
()
V
52
P
MAXDISS
,
×
=
2
633
=
8
Ωπ
(7)
mW
It can easily be seen that power dissipation from BTL mode
operation is of greater concern than SE mode.
Maximum Output Power
The maximum amount of power that can be delivered to a
speaker is a function of the supply voltage and the resistance of
the speaker.
possible from the SSM2250. Maximum output power is defined
as the point at which the output has greater than 1% distortion.
Rev. A | Page 9 of 12
POWER DISSIPATION (W)
0.2
0
075025 100
Figure 17. Maximum Power Dissipation vs. Ambient Temperature
AMBIENT TEMPERATURE (°C)
5
Figure 17 shows the maximum BTL output power
00359-017
SSM2250
MAXIMUM OUTPUT @ THD 1% (W)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
1.5 5.04.54.03.53.02.52.0
Figure 18. Maximum BTL Output Power vs. V
SUPPLY VOLTAGE (V)
RL = 4Ω
RL =8Ω
RL = 16Ω
00359-018
S
Use Figure 18 to find the minimum supply voltage needed to
achieve a specified maximum undistorted output power.
The output power in SE mode is exactly one-fourth the
equivalent output power in BTL mode. This is because twice the
voltage swing across the two BTL outputs results in 4 × the
power delivered to the load.
Figure 19 shows the maximum
output power in SE mode vs. supply voltage for various
headphone loads.
100
RL = 32Ω
RL = 64Ω
RL = 128Ω
00359-019
S
MAXIMUM OUTPUT @ THD 1% (mW)
75
50
25
0
1.5 5.04.54.03.53.02.52.0
Figure 19. Maximum SE Output Power vs. V
SUPPLY VOLTAGE (V)
Example
An application requires only 500 mW to be output in BTL
mode into an 8 Ω speaker. By inspection, the minimum supply
voltage required is 3.3 V.
Speaker Efficiency and Loudness
The effective loudness of 1 W of power delivered into an 8 Ω
speaker is a function of the efficiency of the speaker. The
efficiency of a speaker is typically rated at the sound pressure
level (SPL) at 1 meter in front of the speaker with 1 W of power
applied to the speaker. Most speakers are between 85 dB and
95 dB SPL at one meter at 1 W of power.
Table 5 shows a com-
parison of the relative loudness of different sounds.
Table 5. Typical Sound Pressure Levels
Source of Sound dB SPL
Threshold of Pain 120
Heavy Street Traffic 95
Cabin of Jet Aircraft 80
Average Conversation 65
Average Home at Night 50
Quiet Recording Studio 30
Threshold of Hearing 0
It can easily be seen that 1 W of power into a speaker can
produce quite a bit of acoustic energy.
Shutdown Feature
The SSM2250 can be put into a low power consumption
shutdown mode by connecting Pin 3 to V
. In shutdown
DD
mode, the SSM2250 has low supply current of 60 μA.
Pin 3 should be connected to ground for normal operation.
Connecting Pin 3 to V
shuts down all amplifiers and puts
DD
all outputs into a high impedance state, effectively muting the
SSM2250. A pull-up or pull-down resistor is not required.
Pin 3 should never be left floating, as this could produce unpredictable results.
PC99-Compliant Computer Audio Reference Design
The schematic shown in Figure 20 is a reference design for a
complete audio system in a computer. The design is compliant
with the PC99 standard for computer audio.
The AD1881A is an AC’97, version 2.1, audio codec, available
from Analog Devices. The stereo output from the AD1881A is
coupled into the SSM2250, which is used to drive a mono
internal speaker and stereo headphones. The internal speaker
switching is controlled by the SSM2250 through the normalizing pin on the headphone jack. The AD1881A controls the
shutdown pin on the SSM2250, and is activated through the
power management software drivers installed on the computer.
For more information, refer to the AD1881A data sheet.
Rev. A | Page 10 of 12
SSM2250
R1
AC CLK
SDATA
OUT
BITCLK
SDATA
IN 0
SYNC
RST#
PCBEEP
MONO
PHONE
AUX
LEFT
AUX
27pF
IN
C6
10μF
24.576MHz
C20
R10
10kΩ
C23
0.1μF
C8
22pF
C11
22pF
Y1
SMT
R12
4.7kΩ
R16
4.7kΩ
0.1μF
R8
47Ω
20kΩ
= 5V
AV
DD
R2
100Ω
= 5V
AV
DD
C7
NC
48 47 46 45 44 43 42 41 40 39 38 37
1
2
3
4
5
6
7
8
9
10
11
C22
12
1μF
R11
1kΩ
13 14 15 16 17 18 19 20 21 22 23 24
C26
1μF
R14
4.7kΩ
R17
4.7kΩ
C2
10μF
NCNCNC NC NC NC NC
NC
NC NC
C29
1μF
C31
1μF
NC = NO CONNECT
C3
0.1μF
AD1881A
MONO OUT
C9
36
1μF
35
34
33
32
31
30
29
28
27
26
25
C24
1μF
C27
1μF
C30
1μF
C32
1μF
C33
1μF
C21
0.1μF
C28
0.001μF
R15
4.7kΩ
R19
4.7kΩ
SSM2250
1
NC NC
2
3
4
5
6
7
NC NC
R6
20kΩ
C10
1μF
C14
1μF
AV
DD
C25
1μF
R5
20kΩ
= 5V
R13
4.7kΩ
R18
4.7kΩ
R7
20kΩ
C12
0.1μF
C15
1μF
14
13
12
AV
11
10
9
8
R9
2kΩ
= 5V
DD
C13
0.047μF
C16
270pF
C16
10μF
C1
10μF
+
R3
1kΩ
C4
10μF
+
C17
270pF
LINE IN RIGHT
LINE IN LEFT
MIC IN
CD RIGHT
CD GND
CD LEFT
Figure 20. PC99 Compliant Audio System Reference Design
TO SPEAKER–
TO SPEAKER+
NC
C5
100μF
+
R4
1kΩ
LINE OUT RIGHT
LINE OUT LEFT
C19
0.1μF
00359-020
Rev. A | Page 11 of 12
SSM2250
OUTLINE DIMENSIONS
3.00 BSC
6
10
3.00 BSC
1
PIN 1
0.50 BSC
0.95
0.85
0.75
0.15
0.00
0.27
0.17
COPLANARITY
0.10
COMPLIANT TO JEDEC STANDARDS MO-187-BA
Figure 21. 10-Lead Mini Small Outline Package [MSOP]
4.90 BSC
5
1.10 MAX
SEATING
PLANE
0.23
0.08
(RM-10)
Dimensions shown in millimeters
5.10
5.00
4.90
8°
0°
0.80
0.60
0.40
1.05
1.00
0.80
4.50
4.40
4.30
PIN 1
14
0.65
BSC
0.15
0.05
COMPLIANT TO JEDEC STANDARDS MO-153-AB-1
0.30
0.19
8
6.40
BSC
71
1.20
MAX
SEATING
PLANE
0.20
0.09
COPLANARITY
0.10
8°
0°
0.75
0.60
0.45
Figure 22. 14-Lead Thin Shrink Small Outline Package [TSSOP]
(RU-14)
Dimensions shown in millimeters
ORDERING GUIDE
Model Temperature Range Package Description Package Option Branding
SSM2250RM-R2 −40°C to +85°C 10-Lead MSOP RM-10 AK
SSM2250RM-REEL −40°C to +85°C 10-Lead MSOP RM-10 AK
SSM2250RMZ-R2
SSM2250RMZ-REEL
SSM2250RU-REEL −40°C to +85°C 14-Lead TSSOP RU-14
SSM2250RUZ-REEL
1
Z = Pb-free part, # denotes Pb-free part; may be top or bottom marked.
1
1
1
−40°C to +85°C 10-Lead MSOP RM-10 AK#
−40°C to +85°C 10-Lead MSOP RM-10 AK#
−40°C to +85°C 14-Lead TSSOP RU-14
© 2005 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
C00359–0–6/05(A)
Rev. A | Page 12 of 12
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