Gennum Corporation GL504 Datasheet

A

R

MIC

R

MIC

A

IN

A

OUT

B

IN

MPO

GND

B

OUT

V

B

R

PULL

R

CLIP

6

5

7

8

1

2

3

4

B

BLOCK DIAGRAM

DESCRIPTION

The GL504 is a low current preamplifier designed to drive
the class D series of integrated receivers. This preamp has a
built-in symmetrical peak clipping output limiter, 46 dB of
adjustable gain, and requires few external components.

Composed of two stages, an inverting preamp with gain of
28 dB, and a transconductance block with gain of 18 dB, the
GL504 is easily configured for mid-supply reference as
required by the class D receivers.

The two stages of the GL504 must be AC coupled in order to
maintain the DC bias conditions of each stage. Also, a 48

kΩ resistor, between the output and ground, is used to keep

the receivers at mid-supply reference. The minimal total parts
count, excluding an MPO variable resistor, requires 3

capacitors, a 100 kΩ volume control and the 48 kΩ bias

resistor at the output.

The GL504 is capable of providing a flat frequency response
with very little distortion.

FEATURES

• designed to drive class D integrated receivers

• MPO range externally adjustable

• 150

µA typical current drain

• 46 dB of adjustable gain

• low external parts count

• 8 Pin MICROpac

• 8 Pin PLID

®

• 8 Pin SLT

• Chip (56 x 56 mils)

Au Bump

STANDARD PACKAGING

Document No. 510 - 99 - 06

GL504 - DATA SHEET

Low Current Preamplifier

with Output Limiting

U.S. Patent No. 07/354,327

Revision Date: May 1998

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

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

2

510 - 99 - 06

PARAMETER VALUE / UNITS

Supply Voltage 5 V
Operating Temperature -10°C to +40°C
Storage Temperature -20°C to +70°C

ABSOLUTE MAXIMUM RATINGS

Fig. 1 Test Circuit

PIN CONNECTION

1

4

5

8

A

OUT

B

IN

MPO

GND

A

IN

R

MIC

B

OUT

All resistors in ohms, all capacitors in µF, unless otherwise stated.

V

B

CAUTION

Class 1 ESD Sensitivity

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Amplifier Current I

AMP

RMPO = 0 75 150 225 µA

Microphone Resistance R

MIC

3.0 4.0 5.3 kΩ

Input Referred Noise IRN NFB 0.2 to 10kHz at 12 dB/oct - 2 - µVRMS

Gain A

V

VIN = -80 dBV 44.5 46.5 48.5 dB

MPO Level MPO VIN = -50 dBV -16 -14 -12 dBV

R

MPO

= 0

Change in MPO ∆MPO V

IN

= -50 dBV 10 12 14 dB

R

MPO

= 10 kΩ

Preamp A input Bias Current I

BIAS A

-25 0 +25 nA

Pull-up Resistance R

PULL

40 48 58 kΩ

Gain Loss ∆GAIN R4 = 10 k, V

IN

= -70 dBV, - 0 2.5 dB

RMPO = 50 k

ELECTRICAL CHARACTERISTICS (refer to test circuit) Supply Voltage = 1.3 V, Test Frequency 1kHz

A

B

47k

=1.3 VDC

V

B

OUT

V

0µ1

7

R

PULL

R

CLIP

1

R

MPO

2

3

4

0µ1

R4

6

R

MIC

5

3k9

10

1k

IN

V

0µ22

IN

V

1+40 dB

8

A

100k

I

AMP