FUNCTIONAL BLOCK DIAGRAM

+OUT FORCE

– OUT FORCE

– OUT SENSE

+OUT SENSE

10k

Ω

10k

Ω

50

Ω

50

Ω

GND

ALL RESISTORS 30k

Ω

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: 617/329-4700

Fax: 617/326-8703

FEATURES

Transformer-Like Balanced Output

Drives 10 V RMS Into a 600

Load

Stable When Driving Large Capacitive Loads and Long

Cables

Low Distortion

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

High Slew Rate

15 V/ s 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.