Analog Devices SSM2142S, SSM2142P Datasheet

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Balanced Line Driver

SSM2142

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

FUNCTIONAL BLOCK DIAGRAM

VIN

	50Ω
	+OUT FORCE
	+OUT SENSE
	10kΩ
	– OUT SENSE
	50Ω
	– OUT FORCE
ALL RESISTORS 30kΩ	10kΩ
UNLESS OTHERWISE
INDICATED
GND

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.

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	(VS = 618 V, –408C ≤ TA ≤ +858C, operating in differential mode unless otherwise
SSM2142–SPECIFICATIONS noted. Typical characteristics apply to operation at TA = +258C.)
Parameter	Symbol	Conditions	Min	Typ	Max	Units
INPUT IMPEDANCE	ZIN			10		kΩ
INPUT CURRENT	IIN	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		VS = ±13 V to ±18 V
RATIO STATIC	PSRR		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		RL = 600 Ω
VOLTAGE OFFSET1	VOOS		–250	25	250	mV
DIFFERENTIAL OUTPUT		RL = 600 Ω
VOLTAGE OFFSET	VOOD		–50	15	50	mV
DIFFERENTIAL OUTPUT		VIN = ±7.071 V	±13.8	±14.14
VOLTAGE SWING						V
OUTPUT IMPEDANCE	ZO		45	50	55	Ω
SUPPLY CURRENT	ISY	Unloaded, VIN = 0 V		5.5	7.0	mA
OUTPUT CURRENT, SHORT CIRCUIT	ISC		60	70		mA

NOTES

1Output 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.

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

PIN CONNECTIONS
8-Pin Plastic DIP	16-Pin Wide Body SOL
(P Suffix)				(S Suffix)
						NC
	NC	1			16
						NC
	NC	2			15
						+ FORCE
	– FORCE	3			14
						+ SENSE
	– SENSE	4			13
						+V
	GROUND	5			12
	VIN					–V
		6			11
	NC	7			10	NC
	NC	8			9	NC

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

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