Gennum Corporation LF580 Datasheet

Dual, Continuous, Analog

Highpass Filter

LF580 DATA SHEET

FEATURES

• only 2 small capacitors required

• 200 to 10 kHz adjustable corner frequency

• dual 12 dB/Oct Butterworth filter (24 dB/Oct cascaded)

• 1.1 to 3.0 VDC operating range

• adjustable by a single potentiometer

STANDARD PACKAGING

• 8 pin MICROpac

• 8 pin PLID

®

• Chip (66 x 61mils)

DESCRIPTION

The LF580 continuous analog filter consists of two second
order (12 dB/oct), tunable (0.2 to 10 kHz) highpass Butterworth
filter blocks.

Tracking and corner frequency of each block are controlled
by a single potentiometer. Cascading the two blocks
together results in a single 24dB/oct high pass filter requiring
only two external 0.001 µF capacitors for the filter response.

The output noise of each filter stage is typically 5.6µV.
Cascading the two filter blocks together will produce a
noise level which is

V

= (VN1)2 + (VN2)

N

2

Where VN is the total output noise of both filters, VN1 and
V

is the noise of each filter.

N2

To improve the signal-to-noise ratio of the filter the LF580
should be placed after a preamplifier, provided that the
signal level does not exceed the maximum signal capability
of 50mV

RMS

A

IN

Revision Date: January 2001

V

B

4

8

0.001

All resistors in ohms, all capacitors in microfarads unless otherwise stated

+

AB

_

7

A

OUT

0.001

631

B

IN

BLOCK DIAGRAM

1.8k

+
_

CONTROL

GNDCONTROL

5

B

OUT

Document No. 500 - 73 - 08

GENNUM CORPORATION P.O. Box 489, Stn. A, Burlington, Ontario, Canada L7R 3Y3 tel. [phone]

Web Site: www.gennum.com E-mail: [e-mail]

ABSOLUTE MAXIMUM RATINGS

PIN CONNECTION

PARAMETER VALUE/UNITS

Supply Voltage 5 V DC
Operating Temperature Range -10°C to 50° C
Storage Temperature Range -40°C to 100° C

V

CONTROL

N/C

GND

B

TOP VIEW

4

1

5

8

CAUTION

CLASS 1 ESD SENSITIVITY

ELECTRICAL CHARACTERISTICS

Conditions: Frequency = 1 kHz, Temperature = 25°C, Supply Voltage VB = 1.3 V

Parameter Symbol Conditions Min Typ Max Units
Insertion Loss V
Current Drain I
Corner Frequency f

T

C

Distortion THD V

R
V

IN

CNT

IN

IN

=1 V

=1 V
=1.25 V

Note 1 - 2 3 dB

RMS

= 100 kΩ 200 280 370 µA

Note 2 1300 1650 1900 Hz

RMS

RMS

- 2 5 %

Ouput Noise Note 3 - 8 10 µV
Supply Rejection SR VB = 3.0VDC Note 4 - 45 56 dB

B

B

A

A

OUT

IN

OUT

IN

All parameters and switches remain as shown in Test Circuit unless otherwise stated in "Conditions" column

Notes 1: Insertion Loss = 20 Log(V

2: a) measure output voltage V

b) measure output voltage V

= 1000 x 2

f

C

3: Output Noise = V

modulated with 1V

4: V

Supply Rejection = 20 Log (V

B

(V

V

/

OUT1

OUT2

/100, filter bandwidth 200Hz to 10kHz at 12dB/Oct

OUT

RMS

V

IN

)-12

OUT/VIN

OUT1 (RCNT
OUT2 (RCNT

)

at 1 kHz

)-40

OUT

ATTENUATOR

28dB

=100kΩ)
=10.274kΩ)

0.0011501.82k

82.1

0.001

764

LF580

8

5

31

RL=10k 1000

=100k

R

CNT

R

1.0

B

=4.7

10

+

IC1

40.0 dB

_

100k

+15 V

-15 V

VB=1.3 VDC

DC

DC

V

OUT

500 - 73 - 08

All resistors in ohms, all capacitors in microfarads unless otherwise stated in conditions column

Fig. 1 Test Circuit

2