THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com
THAT 1200, 1203, 1206
Description
The THAT 1200 series of InGenius balanced
line receivers are designed to overcome a serious
limitation of conventional balanced input stages
— notoriously poor common mode rejection in
real world applications. While conventional input
stages may exhibit good rejection characteristics
in the lab and on paper, they perform poorly
when fed from even slightly unbalanced source
impedances — a common situation in almost any
pro sound environment.
Developed by Bill Whitlock of Jensen Trans-
formers, the patented InGenius input stage uses a
unique bootstrap circuit to raise its common-
mode input impedance into the megohm range,
but without the noise penalty that comes from
high-valued resistors. InGenius line receivers
maintain their high CMRR over a wide range of
source impedance imbalances — even when fed
from single-ended sources.
THAT Corporation
InGenius
c226
High-CMRR
Balanced Input Line Receiver
FEATURES
c183 High common-mode rejection
(typical 90 dB at 60 Hz) maintained
under real-world conditions
c183 Excellent solution for hum and
groundloop suppression
c183 Transformer-like noise rejection in
an 8-pin IC, at fraction of
transformer cost and size
APPLICATIONS
c183 Balanced input stages
c183 Summing amplifiers
c183 Transformer front-end
replacements
c183 ADC front-ends
+1
+1
R1 R2
R3 R4
IN-
IN+
REF
CM OUT
Vcc
Vee
Vout+1
-
+
CM IN
Cb
R5
Ra
Rb
Rc
Rd
OA1
OA2
OA3OA4
Figure 1. THAT1200-series equivalent circuit diagram
Pin Name DIP Pin SO Pin
Ref 1 3
In- 2 4
In+ 3 5
Vee 4 6
CM In 5 11
Vout 6 12
Vcc 7 13
CM Out 8 14
Table 1. 1200-series pin assignments
Gain Plastic DIP Plastic SO
0 dB 1200P 1200S
-3 dB 1203P 1203S
-6 dB 1206P 1206S
Table 2. Ordering information
Protected under U.S. Patent No. 5,568,561 and other patents pending.
InGenius
c226
is a trademark of THAT Corporation.
600033 Rev 0A