THAT1420 Datasheet, PDF (1/8 Pages) List of Unclassifed Manufacturers – Balanced Line Drivers

T H AT Corporation
FEATURES
· OutSmartsÔ technology tames
clipping behavior into single-ended
loads
· Pin-compatible with SSM2142
· Balanced, floating output delivers
transformer-like behavior
· Stable when driving long cables
and capacitive loads
· THAT 1430 delivers low output
offset voltage using single capacitor
OutSmartsä Balanced Line Drivers
THAT 1420, 1430
APPLICATIONS
· Differential Line Driver
· Audio Mix Consoles
· Distribution Amplifiers
· Audio Equalizers
· Dynamic Range Processors
· Digital Effects Processors
· Telecommunications Systems
· Instrumentation
· Hi-Fi Equipment
Description
The THAT 1420 and 1430 are a new genera-
tion of audio differential line drivers with im-
proved performance over conventional
cross-coupled monolithic designs. Both models
exhibit low noise and distortion, high slew rate,
stability under difficult loads, wide output swing,
and have outputs which are short-circuit pro-
tected.
In addition both models incorporate patented
OutSmartsÔ technology, a dual feedback-loop de-
sign that prevents the excessive ground currents
typical of cross-coupled output stages (CCOS)
when clipping into single-ended loads¹.
To overcome this problem, the THAT 1420
and 1430 use two individual negative-feedback
loops to separately control the differential output
voltage and common mode output currents, mak-
ing the design inherently more stable and less
sensitive to component tolerances than the CCOS.
Most importantly, the dual-feedback design pre-
vents the loss of common-mode feedback that
plagues the CCOS designs, avoiding the excessive
ground currents and overly-distorted output
waveform that can result when driving sin-
gle-ended loads.
Where minimum output offset voltage with
minimum parts count is desired, the THAT 1430
further improves over existing designs. In con-
ventional CCOS circuits, two relatively high-value
electrolytic capacitors are required to reduce the
offset voltage. By contrast, the THAT 1430 topol-
ogy requires only a resistor and a single film or
ceramic capacitor to achieve the same effect at
lower parts count and price.
10k
Vcc
5k
Din+
In+
Cin+
10k
Dout-
Cin- AD & AC
Gnd
5k
Din-
Dout+
10k
10k
Vee
THAT 1420
50
Out-
CEXT
Sens+
10k
20k
10p
10k
20k
Sens-
50
CEXT
Out+
Figure 1. THAT 1420 Equivalent Circuit Diagram
DIP Pin
Number
SO Pin
Number
1420 Pin
Name
1430 Pin
Name
1
3
Out-
Out-
2
4
Sens-
Cap2
3
5
Gnd
Gnd
4
6
In
In
5
11
Vee
Vee
6
12
Vcc
Vcc
7
13
Sens+
Cap1
8
14
Out+
Out+
Table 1. THAT 1420/1430 pin assignments
1. See Gary Hebert’s paper, An Improved Balanced, Floating Output Driver IC, presented at the 108th AES Convention, Feb. 2000
THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: [phone]; Fax: [phone]; Web: www.thatcorp.com