TL441

LOGARITHMIC AMPLIFIER

SLVS328 – OCTOBER 2000

1

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

D Excellent Dynamic Range

D Wide Bandwidth

D Built-In Temperature Compensation

D Log Linearity (30-dB Sections) ...1 dB Typ

D Wide Input Voltage Range

description

This

amplifier

circuit

contains

four

30-dB

logarithmic stages. Gain in each stage is such that

the output of each stage is proportional to the

logarithm of the input voltage over the 30-dB input

voltage range. Each half of the circuit contains two

of these 30-dB stages summed together in one

differential output that is proportional to the sum of the logarithms of the input voltages of the two stages. The

four stages may be interconnected to obtain a theoretical input voltage range of 120-dB. In practice, this permits

the input voltage range typically to be greater than 80-dB with log linearity of

± 0.5-dB (see application data).

Bandwidth is from dc to 40 MHz.

This circuit is useful in data compression and analog compensation. This logarithmic amplifier is used in log IF

circuitry as well as video and log amplifiers.

The TL441 is characterized for operation over 0

°C to 70°C.

Copyright

© 2000, Texas Instruments Incorporated

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

CA2

VCC –

CA2′

A1

Y

Y

A2

VCC +

NC

CB2

CB2′

GND

B1

Z

Z

B2

N PACKAGE

(TOP VIEW)

NC — No internal connection

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.