ANALOG DEVICES SSM2211 Service Manual

Low Distortion, 1.5 W Audio

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FEATURES

1.5 W output with THD + N < 1%
Differential bridge-tied load output
Single-supply operation: 2.7 V to 5.5 V
Functions down to 1.75 V
Wide bandwidth: 4 MHz
Highly stable phase margin: >80°
Low distortion: 0.2% THD + N @ 1 W output
Excellent power supply rejection

APPLICATIONS

Portable computers
Personal wireless communicators
Hands-free telephones
Speaker phones
Intercoms
Musical toys and talking games

GENERAL DESCRIPTION

The SSM22111 is a high performance audio amplifier that
delivers 1 W rms of low distortion audio power into a bridge­connected 8 Ω speaker load (or 1.5 W rms into a 4 Ω load).

The SSM2211 operates over a wide temperature range and is
specified for single-supply voltages between 2.7 V and 5.5 V.
When operating from batteries, it continues to operate down to

1.75 V. This makes the SSM2211 the best choice for unregulated
applications, such as toys and games.

Featuring a 4 MHz bandwidth and distortion below 0.2% THD
+ N @ 1 W, superior performance is delivered at higher power
or lower speaker load impedance than competitive units.
Furthermore, when the ambient temperature is at 25°C, THD +
N < 1%, and V
delivers a 1.5 W output.

1

Protected by U.S. Patent No. 5,519,576.

Rev. E

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.

= 5 V on a four-layer PCB, the SSM2211

S

Power Amplifier

SSM2211

FUNCTIONAL BLOCK DIAGRAM

IN–

IN+

BYPASS

SHUTDOWN

The low differential dc output voltage results in negligible
losses in the speaker winding and makes high value dc blocking
capacitors unnecessary. The battery life is extended by using
shutdown mode, which typically reduces quiescent current
drain to 100 nA.

The SSM2211 is designed to operate over the −40°C to +85°C
temperature range. The SSM2211 is available in 8-lead SOIC
(narrow body) and LFCSP (lead frame chip scale) surface­mount packages. The advanced mechanical packaging of the
LFCSP models ensures lower chip temperature and enhanced
performance relative to standard packaging options.

Applications include personal portable computers, hands-free
telephones and transceivers, talking toys, intercom systems, and
other low voltage audio systems requiring 1 W output power.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2008 Analog Devices, Inc. All rights reserved.

BIAS

SSM2211

V– (GND)

Figure 1.

A

V

OUT

V

B

OUT

00358-001

SSM2211

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TABLE OF CONTENTS

Features .............................................................................................. 1

Applications ....................................................................................... 1

Functional Block Diagram .............................................................. 1

General Description ......................................................................... 1

Revision History ............................................................................... 2

Electrical Characteristics ................................................................. 3

Absolute Maximum Ratings ............................................................ 5

Thermal Resistance ...................................................................... 5

ESD Caution .................................................................................. 5

Pin Configurations and Function Descriptions ........................... 6

Typical Performance Characteristics ............................................. 7

Product Overview ........................................................................... 14

Thermal Performance—LFCSP ................................................ 14

Typical Applications ....................................................................... 15

Bridged Output vs. Single-Ended Output Configurations ... 15

Speaker Efficiency and Loudness ............................................. 15

Power Dissipation....................................................................... 16

Output Voltage Headroom ........................................................ 17

Automatic Shutdown-Sensing Circuit ..................................... 17

Shutdown-Circuit Design Example ......................................... 18

Start-Up Popping Noise ............................................................. 18

SSM2211 Amplifier Design Example .................................. 18

Single-Ended Applications ........................................................ 19

Driving Two Speakers Single Endedly ..................................... 19

Evaluation Board ........................................................................ 20

LFCSP PCB Considerations ...................................................... 20

Outline Dimensions ....................................................................... 21

Ordering Guide .......................................................................... 22

REVISION HISTORY

4/08—Rev. D to Rev. E

Changes to Features .......................................................................... 1

Changes to General Description .................................................... 1

Changes to Supply Current in Table 1 and Table 2 ...................... 3

Changes to Supply Current in Table 3 ........................................... 4

Changes to Absolute Maximum Ratings ....................................... 5

Changes to Figure 41 ...................................................................... 14

Changes to Equation 7, Equation 8, and Equation 10 ............... 16

Changes to Figure 47 ...................................................................... 17

Changes to Automatic Shutdown-Sensing Circuit Section ...... 18

Changes to SSM2211Amplifier Design Example Section ......... 19

Changes to Driving Two Speakers Single Endedly Section ...... 20

Changes to Figure 50 ...................................................................... 20

Changes to Evaluation Board Section .......................................... 20

Changes to Figure 51 ...................................................................... 20

Changes to Ordering Guide .......................................................... 22

11/06—Rev. C to Rev. D

Updated Format .................................................................. Universal

Changes to General Description .................................................... 1

Changes to Electrical Characteristics ............................................ 3

Changes to Absolute Maximum Ratings ....................................... 5

Added Table 6 .................................................................................... 6

Changes to Figure 32 ...................................................................... 11

Changes to the Product Overview Section ................................. 14

Changes to the Output Voltage Headroom Section ................... 17

Changes to the Start-Up Popping Noise Section ........................ 18

Changes to the Evaluation Board Section ................................... 20

Updated Outline Dimensions ....................................................... 21

Changes to Ordering Guide .......................................................... 21

10/04—Data Sheet Changed from Rev. B to Rev. C

Updated Format .................................................................. Universal

Changes to General Description ..................................................... 1

Changes to Table 5 ............................................................................. 4

Deleted Thermal Performance—SOIC Section ........................... 8

Changes to Figure 31 ...................................................................... 10

Changes to Figure 40 ...................................................................... 12

Changes to Thermal Performance—LFCSP Section ................. 13

Deleted Figure 52, Renumbered Successive Figures .................. 14

Deleted Printed Circuit Board Layout—SOIC Section ............. 14

Changes to Output Voltage Headroom Section ......................... 16

Changes to Start-Up Popping Noise Section .............................. 17

Changes to Ordering Guide .......................................................... 20

10/02—Data Sheet Changed from Rev. A to Rev. B

Deleted 8-Lead PDIP ......................................................... Universal

Updated Outline Dimensions ....................................................... 15

5/02—Data Sheet Changed from Rev. 0 to Rev. A

Edits to General Description ........................................................... 1

Edits to Package Type ....................................................................... 3

Edits to Ordering Guide ................................................................... 3

Edits to Product Overview ............................................................... 8

Edits to Printed Circuit Board Layout Considerations ............. 13

Added section Printed Circuit Board Layout

Considerations—LFCSP ................................................................ 14

Rev. E | Page 2 of 24

SSM2211

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ELECTRICAL CHARACTERISTICS

VDD = 5.0 V, TA = 25°C, RL = 8 Ω, CB = 0.1 µF, VCM = VDD/2, unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

GENERAL CHARACTERISTICS

Differential Output Offset Voltage V
Output Impedance Z

SHUTDOWN CONTROL

Input Voltage High VIH ISY = <100 mA 3.0 V
Input Voltage Low VIL ISY = normal 1.3 V

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = 4.75 V to 5.25 V 66 dB
Supply Current ISY V
Supply Current, Shutdown Mode ISD Pin 1 = VDD (see Figure 32), −40°C ≤ TA ≤ +85°C 0.1 1 μA

DYNAMIC PERFORMANCE

Gain Bandwidth Product GBP 4 MHz
Phase Margin ΦM 86 Degrees

AUDIO PERFORMANCE

Total Harmonic Distortion THD + N P = 0.5 W into 8 Ω, f = 1 kHz 0.15 %
Total Harmonic Distortion THD + N P = 1.0 W into 8 Ω, f = 1 kHz 0.2 %
Voltage Noise Density en f = 1 kHz 85

AVD = 2, −40°C ≤ TA ≤ +85°C 4 50 mV

OOS

0.1 Ω

OUT

A = V

OUT

B = 2.5 V, −40°C ≤ TA ≤ +85°C 9.5 20 mA

OUT

nV√Hz

VDD = 3.3 V, TA = 25°C, RL = 8 Ω, CB = 0.1 µF, VCM = VDD/2, unless otherwise noted.

Table 2.

Parameter Symbol Conditions Min Typ Max Unit

GENERAL CHARACTERISTICS

Differential Output Offset Voltage V
Output Impedance Z

SHUTDOWN CONTROL

Input Voltage High VIH ISY = <100 μA 1.7 V
Input Voltage Low VIL ISY = normal 1 V

POWER SUPPLY

Supply Current ISY V
Supply Current, Shutdown Mode ISD Pin 1 = VDD (see Figure 32), −40°C ≤ TA ≤ +85°C 0.1 1 μA

AUDIO PERFORMANCE

Total Harmonic Distortion THD + N P = 0.35 W into 8 Ω, f = 1 kHz 0.1 %

AVD = 2, −40°C ≤ TA ≤ +85°C 5 50 mV

OOS

0.1 Ω

OUT

A = V

OUT

B = 1.65 V, −40°C ≤ TA ≤ +85°C 5.2 20 mA

OUT

Rev. E | Page 3 of 24

SSM2211

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VDD = 2.7 V, TA = 25°C, RL = 8 Ω, CB = 0.1 µF, VCM = VDD/2, unless otherwise noted.

Table 3.

Parameter Symbol Conditions Min Typ Max Unit

GENERAL CHARACTERISTICS

Differential Output Offset Voltage V
Output Impedance Z

SHUTDOWN CONTROL

Input Voltage High VIH ISY = <100 mA 1.5 V
Input Voltage Low VIL ISY = normal 0.8 V

POWER SUPPLY

Supply Current ISY V
Supply Current, Shutdown Mode ISD Pin 1 = VDD (see Figure 32), −40°C ≤ TA ≤ +85°C 0.1 1 μA

AUDIO PERFORMANCE

Total Harmonic Distortion THD + N P = 0.25 W into 8 Ω, f = 1 kHz 0.1 %

AVD = 2 5 50 mV

OOS

0.1 Ω

OUT

A = V

OUT

B = 1.35 V, −40°C ≤ TA ≤ +85°C 4.2 20 mA

OUT

Rev. E | Page 4 of 24

SSM2211

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ABSOLUTE MAXIMUM RATINGS

Absolute maximum ratings apply at TA = 25°C, unless
otherwise noted.

Table 4.

Parameter Rating

Supply Voltage 6 V
Input Voltage VDD
Common-Mode Input Voltage VDD
ESD Susceptibility 2000 V
Storage Temperature Range −65°C to +150°C
Operating Temperature Range −40°C to +85°C
Junction Temperature Range −65°C to +165°C
Lead Temperature, Soldering (60 sec) 300°C

Stresses above those listed 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.

THERMAL RESISTANCE

is specified for the worst-case conditions, that is, a device

θ

JA

soldered in a circuit board for surface-mount packages.

Table 5. Thermal Resistance

Package Type θJA Unit

8-Lead LFCSP_VD (CP-Suffix)1 50 °C/W

8-Lead SOIC_N (S-Suffix)2 121 °C/W

1

For the LFCSP_VD, θJA is measured with exposed lead frame soldered to the PCB.

2

For the SOIC_N, θJA is measured with the device soldered to a four-layer PCB.

ESD CAUTION

Rev. E | Page 5 of 24

SSM2211

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PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

PIN 1

1SHUTDOWN

SHUTDOWN

BYPASS

IN+

IN–

1

SSM2211

2

3

TOP VIEW

(Not to Scale)

4

V

B

8

OUT

V–

7

6

V+

V

A

5

OUT

00358-002

2BYPASS

3IN+

4IN–

INDICATO R

SSM2211

TOP VIEW

(Not to Scale)

Figure 2. 8-Lead SOIC_N Pin Configuration (R-8) Figure 3. 8-Lead LFCSP_VD Pin Configuration (CP-8-2)

Table 6. Pin Function Descriptions

Pin No. Mnemonic Description

1 SHUTDOWN Shutdown Enable.
2 BYPASS Bypass Capacitor.
3 IN+ Noninverting Input.
4 IN− Inverting Input.
5 V

A Output A.

OUT

6 V+ Positive Supply.
7 V− Negative Supply.
8 V

B Output B.

OUT

8V

7V–

6V+

5V

OUT

OUT

B

A

00358-003

Rev. E | Page 6 of 24

SSM2211

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TYPICAL PERFORMANCE CHARACTERISTICS

10

1

TA = 25°C
V

= 5V

DD

A

= 2 (BTL)

VD

R

= 8Ω

L

P

= 500mW

L

CB = 0

10

1

TA = 25°C
V

= 5V

DD

A

= 2 (BTL)

VD

R

= 8Ω

L

P

= 1W

L

CB = 0

CB = 0.1μF

THD + N (%)

CB = 1μF

0.1

0.01
20 100 20k

FREQUENCY (Hz)

1k 10k

Figure 4. THD + N vs. Frequency

10

CB = 0

1

CB = 1μF

THD + N (%)

0.1
TA = 25°C

V

= 5V

DD

A

= 10 (BTL)

VD

R

= 8Ω

L

P

= 500mW

L

0.01
20 100 20k

CB = 0.1μF

1k 10k

FREQUENCY (Hz)

Figure 5. THD + N vs. Frequency

10

00358-004

00358-005

CB = 0.1μF

THD + N (%)

0.1

CB = 1μF

0.01
20 100 20k

FREQUENCY (Hz)

1k 10k

Figure 7. THD + N vs. Frequency

10

CB = 0

1

THD + N (%)

CB = 1μF

0.1
TA = 25°C

V

= 5V

DD

A

= 10 (BTL)

VD

R

= 8Ω

L

P

= 1W

L

0.01
20 100 20k

CB = 0.1μF

1k 10k

FREQUENCY (Hz)

Figure 8. THD + N vs. Frequency

10

00358-007

00358-008

CB = 0.1μF

1

CB = 1μF

THD + N (%)

0.1
TA = 25°C

V

= 5V

DD

A

= 20 (BTL)

VD

R

= 8Ω

L

P

= 500mW

L

0.01
20 100 20k

FREQUENCY (Hz)

1k 10k

00358-006

Figure 6. THD + N vs. Frequency

Rev. E | Page 7 of 24

CB = 0.1μF

1

CB = 1μF

THD + N (%)

0.1
TA = 25°C

V

= 5V

DD

A

= 20 (BTL)

VD

R

= 8Ω

L

P

= 1W

L

0.01
20 100 20k

FREQUENCY (Hz)

1k 10k

Figure 9. THD + N vs. Frequency

00358-009

SSM2211

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10

TA = 25°C
V

= 5V

DD

A

= 2 (BTL)

VD

R

= 8Ω

L

FREQUENCY = 20Hz
C

= 0.1μF

B

1

10

1

TA = 25°C
V

= 3.3V

DD

A

= 2 (BTL)

VD

R

= 8Ω

L

P

= 350mW

L

CB = 0

THD + N (%)

0.1

0.01
20n 0.1 2

10

TA = 25°C

= 5V

V

DD

= 2 (BTL)

A

VD

= 8Ω

R

L

FREQUENCY = 1kHz
C

= 0.1μF

B

1

THD + N (%)

0.1

0.01
20n 0.1 2

10

TA = 25°C
V

= 5V

DD

A

= 2 (BTL)

VD

R

= 8Ω

L

FREQUENCY = 20kHz
C

= 0.1μF

B

1

P

(W)

OUTPUT

Figure 10. THD + N vs. P

P

(W)

OUTPUT

Figure 11. THD + N vs. P

OUTPUT

OUTPUT

THD + N (%)

0.1

CB = 1μF

1

00358-010

0.01
20 100 20k

CB = 0.1μF

FREQUENCY (Hz)

1k 10k

00358-013

Figure 13. THD + N vs. Frequency

10

CB = 0

1

THD + N (%)

1

00358-011

CB = 1μF

0.1

0.01
20 100 20k

CB = 0.1μF

TA = 25°C
V

DD

A

VD

R

= 8Ω

L

P

= 350mW

L

FREQUENCY (Hz)

1k 10k

= 3.3V
= 10 (BTL)

00358-014

Figure 14. THD + N vs. Frequency

10

1

CB = 0.1μF

THD + N (%)

0.1

0.01
20n 0.1 2

P

(W)

OUTPUT

Figure 12. THD + N vs. P

OUTPUT

1

00358-012

Rev. E | Page 8 of 24

CB = 1μF

THD + N (%)

0.1
TA = 25°C

V

= 3.3V

DD

A

= 20 (BTL)

VD

R

= 8Ω

L

P

= 350mW

L

0.01
20 100 20k

FREQUENCY (Hz)

1k 10k

Figure 15. THD + N vs. Frequency

00358-015