FEATURES
• High CMRR: typ. 90 dB at 60 Hz
• Extremely high common-mode input
impedance
• Maintains balance under real-world
conditions
• Transformer-like performance in an IC
• Excellent audio performance
• Wide bandwidth: typ. > 22 MHz
• High slew rate: typ. 12 V/us
• Low distortion: typ. 0.0005 % THD
• Low noise: typ. -106 dBu
• Several gains: 0 dB, -3 dB, & -6 dB
InGenius High-CMRR
Balanced Input Line Receiver ICs
THAT 1200, 1203, 1206
APPLICATIONS
• Balanced Audio Line Receivers
• Instrumentation Amplifiers
• Differential Amplifiers
• Transformer Front-End Replacements
• ADC Front-Ends
Description
The THAT 1200-series InGenius balanced
line receivers overcome a serious limitation of
conventional balanced input stages: poor com-
mon mode rejection in real-world applications.
While conventional input stages measure well in
the lab and perform well on paper, they fail to
live up to their CMRR specs when fed from even
slightly unbalanced source impedances — a
common situation in almost any pro sound envi-
ronment. This is because conventional stages
have low common-mode input impedance, which
interacts with imbalances in source impedance to
unbalance common-mode signals, making them
indistinguishable from desired, balanced signals.
Developed by Bill Whitlock of Jensen Trans-
formers, the patented InGenius input stage uses
clever bootstrapping to raise its common-mode
input impedance into the megohm range without
the noise penalty from the obvious solution of
using high-valued resistors. Like transformers,
InGenius line receivers maintain their high
CMRR over a wide range of source impedance
imbalances — even when fed from single-ended
sources. But unlike transformers, these wide
bandwidth solid state devices offer dc-coupling,
low distortion, and transparent sound in a small
package at reasonable cost.
R6
IN-
R7
R8
IN+
R9
OA1
+1
R10
24K
R11
24K
+1
OA2
CM IN
R1
OA4
+1
R3
R2
OA3
-
+
R4
R5
24K
CM OUT
Vcc
Vee
Vout
REF
Part no.
THAT1200
THAT1203
THAT1206
Cb
R6 , R9
0
7k
7k
R7 , R8
24 k
17 k
17 k
R1 , R3
6k
6k
7k
R2 , R4
6k
6k
5k
Figure 1. THAT 1200-series equivalent circuit diagram
Pin Name
DIP Pin
SO Pin
Ref 1
1
In- 2
2
In+ 3
3
Vee 4
4
CM In
5
5
Vout
6
6
Vcc 7
7
CM Out
8
8
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 Numbers, 5,568,561 and 6,160,451. Additional patents pending.
InGenius is a registered trademark of THAT Corporation.
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 © 2017, THAT Corporation; All rights reserved; Doc 600033 Rev 01
