Analog Devices SSM2142S, SSM2142P Datasheet

FUNCTIONAL BLOCK DIAGRAM

+OUT FORCE

– OUT FORCE

– OUT SENSE

+OUT SENSE

10kΩ

10kΩ

50Ω

50Ω

V

IN

GND

ALL RESISTORS 30kΩ
UNLESS OTHERWISE
INDICATED

REV. B

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.

a

Balanced Line Driver

SSM2142

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

FEATURES
Transformer-Like Balanced Output
Drives 10 V RMS Into a 600 V Load
Stable When Driving Large Capacitive Loads and Long

Cables

Low Distortion

0.006% typ 20 Hz–20 kHz, 10 V RMS into 600 V

High Slew Rate

15 V/ms typ

Low Gain Error

(Differential or Single-Ended); 0.7% typ
Outputs Short-Circuit Protected
Available In Space-Saving 8-Pin Mini-DIP Package
Low Cost

APPLICATIONS
Audio Mix Consoles
Distribution Amplifiers
Graphic and Parametric Equalizers
Dynamic Range Processors
Digital Effects Processors
Telecommunications Systems
Industrial Instrumentation
Hi-Fi Equipment

GENERAL DESCRIPTION

The SSM2142 is an integrated differential-output buffer
amplifier that converts a single-ended input signal to a balanced
output signal pair with high output drive. By utilizing low noise
thermally matched thin film resistors and high slew rate
amplifiers, the SSM2142 helps maintain the sonic quality of
audio systems by eliminating power line hum, RF interference,
voltage drops, and other externally generated noise commonly
encountered with long audio cable runs. Excellent rejection of
common-mode noise and offset errors is achieved by laser
trimming of the onboard resistors, assuring high gain accuracy.
The carefully designed output stage of the SSM2142 is capable
of driving difficult loads, yielding low distortion performance
despite extremely long cables or loads as low as 600 Ω, and is
stable over a wide range of operating conditions.

Based on a cross-coupled, electronically balanced topology, the
SSM2142 mimics the performance of fully balanced
transformer-based solutions for line driving. However, the
SSM2142 maintains lower distortion and occupies much less
board space than transformers while achieving comparable
common-mode rejection performance with reduced parts count.

The SSM2142 in tandem with the SSM2141 differential
receiver establishes a complete, reliable solution for driving and
receiving audio signals over long cables. The SSM2141 features
an Input Common-Mode Rejection Ratio of 100 dB at 60 Hz.
Specifications demonstrating the performance of this typical
system are included in the data sheet.

REV. B

SSM2142–SPECIFICATIONS

Parameter Symbol Conditions Min Typ Max Units

INPUT IMPEDANCE Z

IN

10 kΩ

INPUT CURRENT I

IN

VIN = ±7.071 V ±750 ±900 µA
GAIN, DIFFERENTIAL 5.8 5.98 dB
GAIN, SINGLE-ENDED Single-Ended Mode 5.7 5.94 dB
GAIN ERROR, DIFFERENTIAL RL = 600 Ω 0.7 2 %
POWER SUPPLY REJECTION

RATIO STATIC PSRR VS = ±13 V to ±18 V 60 80 dB
OUTPUT COMMON-MODE REJECTION OCMR See Test Circuit; f = 1 kHz –38 –45 dB
OUTPUT SIGNAL BALANCE RATIO SBR See Test Circuit; f = 1 kHz –35 –40 dB
TOTAL HARMONIC DISTORTION

Plus Noise THD+N 20 Hz to 20 kHz, 0.006 %

VO = 10 V rms, RL = 600 Ω
SIGNAL-TO-NOISE RATIO SNR VIN = 0 V –93.4 dBu
HEADROOM HR CLIP Level = 10.5 V rms +93.4 dBu
SLEW RATE SR 15 V/µs
OUTPUT COMMON-MODE

VOLTAGE OFFSET

1

V

OOS

RL = 600 Ω –250 25 250 mV
DIFFERENTIAL OUTPUT

VOLTAGE OFFSET V

OOD

RL = 600 Ω –50 15 50 mV
DIFFERENTIAL OUTPUT

VOLTAGE SWING VIN = ±7.071 V ±13.8 ±14.14 V

OUTPUT IMPEDANCE Z

O

45 50 55 Ω

SUPPLY CURRENT I

SY

Unloaded, VIN = 0 V 5.5 7.0 mA
OUTPUT CURRENT, SHORT CIRCUIT I

SC

60 70 mA

NOTES

1

Output common-mode offset voltage can be removed by inserting dc blocking capacitors in the sense lines. See Applications Information.

Specifications subject to change without notice.

(VS = 618 V, –408C ≤ TA ≤ +858C, operating in differential mode unless otherwise
noted. Typical characteristics apply to operation at TA = +258C.)

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±18 V

Storage Temperature . . . . . . . . . . . . . . . . . . –60°C to +150°C

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

Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . +150°C

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

Output Short Circuit Duration (Both Outputs) . . . . Indefinite

*Stresses above those listed under “Absolute Maximum Ratings” may cause

permanent damage to the device. These are stress ratings only; the functional
operation of the device at these or any other conditions above those indicated in the
operational sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.

ORDERING GUIDE

Operating Package Package

Model Temperature Range Description Option

SSM2142P –40°C to +85°C Plastic DIP N-8
SSM2142S* –40°C to +85°C SOL R-16

*For availability of SOIC package, contact your local sales office.

PIN CONNECTIONS

8-Pin Plastic DIP

(P Suffix)

–2–

16-Pin Wide Body SOL

(S Suffix)

– FORCE

– SENSE

GROUND

V

IN

+ FORCE
+ SENSE
+V

–V

NC
NC

NC
NC

NC
NC

NC

NC

1

2
3

4
5

6

7

8

16

15

14

13

12

11

10

9