1606 데이터 시트보기 (PDF) - THAT Corporation

부품명

상세내역

제조사

1606

Balanced Line Driver ICs

THAT Corporation 

THAT1606/1646 Balanced Line Driver ICs

Page 9 of 12

Document 600078 Rev 05

Vcc

Input

Amplifier

Block

(from fig.

5, 6, or 7)

Vcc

Input

Gnd

Vee

U1

Out+

Out-

D3

1N4004

D5

1N4004

D6

1N4004

D4

1N4004

L1

Ferrite Bead

L2

C8

100p

Ferrite Bead

C3

100p

XLR (M)

12

3

Vee

Figure 8. THAT 16x6 applications circuit with output common-mode offset protection, RFI protection, and surge protection

of Figure 8 includes two 100 pF bypass capacitors

C3 and C8 and two ferrite beads, whose purpose is

to redirect this RF energy to the chassis before it can

circulate inside the product's box and couple RF into

other portions of the circuit. The capacitors should

be located as close as possible to the output connec-

tor and connected via a low-inductance path to chas-

sis ground, with the ferrite beads placed very nearby.

These components ensure that RFI current is di-

rected to the chassis and not through the relatively

low-impedance output of the 1606/1646. The bypass

capacitors and ferrite beads will have no effect on the

gain error of these line drivers at audio frequencies.

Output protection

The 1606 and 1646 each incorporate a propri-

etary internal protection scheme, which will suffice

for many situations seen in the field. However, one

might foresee having the line driver's output mistak-

enly plugged directly into a microphone preamplifier

input that has +48V phantom power applied. When

this happens, the ac coupling capacitors on the

preamp's input will discharge into the low-impedance

output of the 1606/1646. This can result in surge

currents of over 2 amperes6. The amount of energy

stored in these capacitors is directly proportional to

the capacitor value, which is, of course, not under the

1606/1646 designer's control. The 1606/1646's in-

ternal protection network will withstand this abuse

for coupling capacitors up to about 33 uF.

To protect against microphone preamplifiers that

incorporate larger values of capacitance, a pair

1N4004 diodes from each output to the supply rails,

as shown in Figure 8, is recommended. This shunts

the discharge current to the power supply bypass

and filter capacitors, thus protecting the output of

the 1606 or 1646.

Closing thoughts

The integrated balanced line driver is one of those

highly useful, cost-effective functional blocks that can

provide significant improvement over discrete de-

signs. The THAT 1646 goes a step or two further by

improving over existing components. Both incorpo-

rate OutSmarts technology to tame the aberrant sin-

gle-ended clipping behavior of conventional

cross-coupled output stages.

For more information on these or other THAT

Corporation integrated circuits, please contact us di-

rectly, or through one of our international distribu-

tors.

6. Hebert, Gary K., Thomas, Frank W., "The 48V Phantom Menace", presented at the 110th Audio Engineering Society Convention, May, 2001

THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA

Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com

Copyright © 2011, THAT Corporation; All rights reserved.

Share Link: