Analog Devices SSM2018, SSM2118 Datasheet

FUNCTIONAL BLOCK DIAGRAMS

GENERAL DESCRIPTION

The SSM2018T and SSM2118T represent continuing evolu­tion of the Frey Operational Voltage Controlled Element
(OVCE) topology that permits flexibility in the design of high
performance volume control systems. Voltage (SSM2018T)
and differential current (SSM2118T) output versions are of­fered, both laser-trimmed for gain core symmetry and offset. As
a result, the SSM2018T is the first professional audio quality
VCA to offer trimless operation. The SSM2118T is ideal for
low noise summing in large VCA based systems.

Due to careful gain core layout, the SSM2018T/SSM2118T
combine the low noise of Class AB topologies with the low dis­tortion of Class A circuits to offer an unprecedented level of
sonic transparency. Additional features include differential in­puts, a 140 dB gain range, and a high impedance control port.
The SSM2018T provides an internal current-to-voltage con­verter; thus no external active components are required. The
SSM2118T has fully differential current outputs that permit
high noise-immunity summing of multiple channels.

Both devices are offered in 16-pin plastic DIP and SOIC pack­ages and guaranteed for operation over the extended industrial
temperature range of –40°C to +85°C.

*Protected by U.S. Patent Nos. 4,471,320 and 4,560,947.

FEATURES
117 dB Dynamic Range

0.006% Typical THD+N (@ 1 kHz, Unity Gain)
140 dB Gain Range
No External Trimming Required
Differential Inputs
Complementary Gain Outputs
Buffered Control Port
I–V Converter On-Chip (SSM2018T)
Differential Current Outputs (SSM2118T)
Low External Parts Count
Low Cost

Trimless

Voltage Controlled Amplifiers

SSM2018T/SSM2118T*

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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.

One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106,
U.S.A. Tel: [phone] Fax: [phone]

REV. A

a

V

C

–IN

+IN

V

G

V

1–G

–I

G

–I

1–G

GAIN

CORE

G

1–G

SSM-2018T

V

C

–IN

+IN

+I

G

V

1–G

–I

G

–I

1–G

GAIN

CORE

G

1–G

SSM-2118T

REV. A

–2–

SSM1018T/SSM2118T–SPECIFICATIONS

ELECTRICAL SPECIFICATIONS

Parameter Conditions Min Typ Max Units

AUDIO PERFORMANCE

1

Noise VIN = GND, 20 kHz Bandwidth –95 –93 dBu
Headroom Clip Point = 1% THD+N +22 dBu
Total Harmonic Distortion plus Noise 2nd and 3rd Harmonics Only (+25°C to +85°C)

A

V

= 0 dB, VIN = +10 dBu 0.006 0.025 %

A

V

= +20 dB, VIN = –10 dBu 0.013 0.04 %

AV = –20 dB, VIN = +10 dBu

2

0.013 0.04 %

INPUT AMPLIFIER

Bias Current V

CM

= 0 V 0.25 1 µA

Offset Voltage V

CM

= 0 V 1 15 mV

Offset Current V

CM

= 0 V 10 100 nA

Input Impedance 4MΩ
Common-Mode Range ±13 V
Gain Bandwidth VCA Configuration 0.7 MHz

VCP Configuration 14 MHz

Slew Rate 5V/µs

OUTPUT AMPLIFIER (SSM2018T)

Offset Voltage V

IN

= 0 V, VC = +4 V 1.0 15 mV

Output Voltage Swing I

OUT

= 1.5 mA
Positive +10 +13 V
Negative –10 –14 V

Minimum Load Resistance For Full Output Swing 9 kΩ

CONTROL PORT

Bias Current 0.36 1 µA
Input Impedance 1MΩ
Gain Constant Device Powered in Socket > 60 sec –30 mV/dB
Gain Constant Temperature Coefficient –3500 ppm/°C
Control Feedthrough 0 dB to –40 dB Gain Range ±1 ±4mV
Maximum Attenuation VC = +4 V 100 dB

POWER SUPPLIES

Supply Voltage Range ±5 ±18 V
Supply Current 11 15 mA
Power Supply Rejection Ratio 80 dB

NOTES

1

SSM2118T tested and characterized using OP275 as current-to-voltage converter, see figure next page.

2

Guaranteed by characterization data and testing at AV = 0 dB.

Specifications subject to change without notice.

[VS = ±15 V, AV = 0 dB, RL = 100 kΩ, f = 1 kHz, 0 dBu = 0.775 V rms, simple VCA application

circuit with 18 kΩ resistors, –VIN floating, and Class AB gain core bias (RB = 150 kΩ), –40°C < TA < +85°C, unless otherwise noted. Typical
specifications apply at TA = +25°C.]

REV. A

–3–

SSM2018T/SSM2118T

ABSOLUTE MAXIMUM RATINGS

1

Supply Voltage

Dual Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .±18 V

Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±V

S

Operating Temperature Range . . . . . . . . . . . . .–40°C to +85°C

Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C

Junction Temperature (T

J

) . . . . . . . . . . . . . . . . . . . . . +150°C

Lead Temperature (Soldering, 60 sec) . . . . . . . . . . . . . +300°C

THERMAL CHARACTERISTICS

Thermal Resistance

2

16-Pin Plastic DIP

θ

JA

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76°C/W

θ

JC

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33°C/W

16-Pin SOIC

θ

JA

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92°C/W

θ

JC

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27°C/W

TRANSISTOR COUNT

Number of Transistors

SSM2018T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

SSM2118T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

ESD RATINGS

883 (Human Body) Model . . . . . . . . . . . . . . . . . . . . . . . 500 V

EIAJ Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 V

1

Stresses above those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those indicated in the
operation section of this specification is not implied. Exposure to absolute maxi­mum rating conditions for extended periods may affect device reliability.

2

θJA is specified for worst-case conditions, i.e., θJA is specified for device in socket

for P-DIP and device soldered in circuit board for SOIC package.

ORDERING GUIDE

Model Temperature Range Package Option*

SSM2018TP –40°C to +85°C N-16
SSM2018TS –40°C to +85°C R-16
SSM2118TP –40°C to +85°C N-16
SSM2118TS –40°C to +85°C R-16

*N = Plastic DIP; R = SOL.

PIN CONFIGURATIONS

16-Lead Plastic DIP

and SOL

16-Lead Plastic DIP

and SOL

+I

1–G

V+ BAL

COMP 1

+IN
–IN

MODE
V

C

V–

–I

1–G

–I

G

V

G

GND

COMP 2 COMP 3

1
2

16
15

5
6
7

12
11
10

3
4

14
13

89

TOP VIEW

(Not to Scale)

SSM2018T

V

1–G

+I

1–G

V+

BAL

COMP 1

+IN
–IN

MODE
V

C

V–

–I

1–G

GND

COMP 2 COMP 3

1
2

16
15

5
6
7

12
11
10

3
4

14
13

89

TOP VIEW

(Not to Scale)

SSM2118T

V

1–G

–I

G

+I

G

SSM2018T Typical Application Circuit

SSM2118T Typical Application Circuit

1µF

18k

V

IN+

V–

150k

A1

10k

10k

18k

18k

500k

50pF

V

OUT

GLOBAL

SYMMETRY

TRIM

FROM

ADDITIONAL

SSM2118Ts

V–

1µF

18k

V

IN–

47pF

1µF

3k

V

CONTROL

V+

50pF

*

470k

OPTIONAL
TRIM

47k

47k

A1, A2: OP275

1
2

5
6
7

3
4

8

16
15

12
11
10

14
13

9

SSM2118T

A2

1k

*

FOR MORE THAN 2 SSM2118Ts

WARNING!

ESD SENSITIVE DEVICE

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 the SSM2018T/SSM2118T 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.

V+

1µF

150k

18k

V+

18k

V

IN+

1µF

18k

V

IN–

47pF

1µF

50pF

1k

V

CONTROL

3k

V

OUT

V–

1
2

16
15

5
6
7

12
11
10

3
4

14
13

89

SSM2018T

–4–

SSM2018T/SSM2118T–Typical Characteristics

REV. A

0.1

0.010

0.001

THD + N – %

20 100 1k 10k

20k

FREQUENCY – Hz

AV = +20dB

AV = –20dB

AV = 0dB

TA = +25°C
V

S

= ±15V

R

F

= 18kΩ

Figure 1. SSM2018T THD + N Frequency (80 kHz Low-Pass
Filter, for A

V

= 0 dB, VIN = 3 V rms; for AV = +20 dB,

V

IN

= 0.3 V rms; for AV = –20 dB, VIN = 3 V rms)

100

0

0.025

30

10

20

0.000

60

40

50

70

80

90

0.0200.0150.0100.005

DISTORTION – %

UNITS

TA = +25°C
AV = 0dB
300 UNITS
V

IN

= 10dBu

VS = ±15V

Figure 2. SSM2018T Distortion Distribution

1

0.1

0.010

0.001

THD + N – %

0.1

11020

AMPLITUDE – V

RMS

TA = +25°C
R

F

= 18kΩ

V

S

= ±15V

Figure 3. SSM2018T THD + N vs. Amplitude (Gain = 0 dB,
f

IN

= 1 kHz, 80 kHz Low-Pass Filter)

1

0.1

0.010

0.001

THD + N – %

10m

0.1 1 2

AMPLITUDE – V

RMS

TA = +25°C
V

S

= ±15V

R

F

= 18kΩ

Figure 4. SSM2018T THD + N vs. Amplitude
(Gain = +20 dB, f

IN

=1 kHz, 80 kHz Low-Pass Filter)

1.0

0.01

0.001
–60 –40 20–20

0.1

040

TA = +25°C
V

S

= ±15V

R

F

= 18kΩ

GAIN – dB

THD + N – %

Figure 5. SSM2018T THD + N vs. Gain (fIN = 1 kHz;
for –60 dB

≤

AV ≤ –20 dB, VIN = 10 V rms;

for 0 dB

≤

AV ≤ +20 dB, VIN = 1 V rms)

THD + N – %

0.1

0.001

0 ±12

0.01

TA = +25°C
R

F

= 18kΩ

±3 ±6 ±9 ±15 ±18

SUPPLY VOLTAGE – Volts

Figure 6. SSM2018T THD + N vs. Supply Voltage
(A

V

= 0 dB, VIN = 1 V rms, fIN = 1 kHz, 80 kHz

Low-Pass Filter)

REV. A

–5–

SSM2018T/SSM2118T

LOAD RESISTANCE – Ω

MAXIMUM OUTPUT SWING – V

PEAK

±15

±12

0

100 1k 100k10k

±9

±6

±3

RF = 18kΩ
TA = +25°C
V

S

= ±15V

Figure 10. SSM2018T Maximum Output Swing vs.
Load Resistance, (THD = 1 % max)

100

0

40

30

10

–60

20

–80

60

40

50

70

80

90

200–20–40

TA = +25°C
V

S

= ±15V

GAIN – dB

OUTPUT OFFSET – mV

Figure 11. SSM2018T Output Offset vs. Gain

+10

0

–15

1k 1M100k10k100

–5

–10

+5

FREQUENCY – Hz

TA = +25°C
VS = ±15V

GAIN – dB

0

–135

–45

–90

PHASE – Degrees

GAIN

PHASE

Figure 12. SSM2018T Gain/Phase vs. Frequency

Figure 7. SSM2018T Noise Density vs. Frequency

0

±15

±5

±5

±10

0

±20

±20±15±10

SUPPLY VOLTAGE – Volts

OUTPUT VOLTAGE SWING – V

PEAK

RL = ∞Ω

RL = 10kΩ

RF = 18kΩ
T

A

= +25°C

Figure 8. SSM2018T Maximum Output Swing vs.
Supply Voltage (THD = 1% max)

FREQUENCY – Hz

MAXIMUM OUTPUT SWING – V

PEAK

RL = ∞

RL = 10k

RF = 18kΩ
T

A

= +25°C

V

S

= ±15V

±9

0

1k 10k 100k

±3

±6

±12

±15

Figure 9. SSM2018T Maximum Output Swing vs.
Frequency (THD = 1 % max)

500

300

0

100 100k10k1k10

200

100

400

FREQUENCY – Hz

NOISE DENSITY – nV/√Hz

TA = +25°C
VS = ±15V