FEATURES
• Balanced, transformer-like floating
output
• OutSmarts® technology improves
clipping into single-ended loads
• Stable driving long cables and
capacitive loads
• High output: 18Vrms into 600 Ω
• Low noise: -101 dBu
• Low distortion: 0.0007% @ 1kHz
• Industry-standard pinout
Balanced Line Driver ICs
THAT 1280, 1283,T1H2A8T6 a1n6d061,2166046_
APPLICATIONS
• Differential Line Drivers
• Audio Mixing Consoles
• Distribution Amplifiers
• Hi-Fi Equipment
• Audio Equalizers
• Dynamic Range Processors
• Digital Effects Processors
• Telecommunications Systems
• Instrumentation
Description
The THAT 1606 and 1646 are a new generation
of monolithic audio differential line drivers offering
improved performance over conventional cross-
coupled designs. Based on a high-performance, fully
differential opamp and laser-trimmed thin-film
resistors, both families exhibit low noise and
distortion, high slew rate, and wide output swing.
The parts are stable when driving difficult loads, and
have short-circuit protected outputs.
Designed from the ground up in THAT's
complementary dielectric isolation process, both
models incorporate THAT's patented OutSmarts1
technology. This is a dual feedback-loop design that
prevents the excessive ground currents typical of
cross-coupled output stages (CCOS) when clipping
into single-ended loads. OutSmarts uses two
individual negative-feedback loops to separately
control the differential output voltage and common
mode output currents, making the designs
inherently more stable and less sensitive to
component tolerances than common CCOSes. As a
result, THAT's topology prevents the loss of
common-mode feedback that plagues common
CCOS designs when clipping into single-ended loads.
This avoids excessive ground currents that would
otherwise upset power supplies and create
additional distortion, even in adjacent channels.
The 1646 is pin-compatible with the TI DRV134
and DRV135, as well as the Analog Devices
SSM2142. The 1606 offers an advanced common-
mode offset voltage reduction scheme, which
requires a small single capacitor instead of the two
electrolytics required by the 1646 and its pin-
compatible cousins. Additionally, the 1606 features
differential inputs in a space-saving 16-pin QSOP
package. Both parts offer +6 dB gain.
10k
Vcc
In+ 5k Din+
Cin+
Cin-
Gnd 5k Din-
10k
Dout-
Dout+
10k
10k
Vee
THAT 1646
25
Out-
Sns-
10k 20k
10p
CEXT
10k 20k
Sns+
25 CEXT
Out+
1646
1606
Pin
DIP8
SO8
SO16W QSOP16
1
Out- Out-
NC Gnd*
2
Sns-
Sns-
NC
NC
3
Gnd Gnd
Out- Out-
4
In
In
Sns-
Cap1
5
Vee Vee
Gnd Gnd
6 Vcc Vcc In In-
7
Sns+
Sns+
NC
In+
8
Out+
Out+
NC Gnd*
9 — — NC Gnd*
10 — — NC NC
11 — — Vee Vee
12 — — Vcc Vcc
13
—
—
Sns+
Cap2
14
—
—
Out+
Out+
15 — — NC NC
16 — — NC Gnd*
* See "Thermal Considerations" section on page 10
Figure 1. THAT 1646 Equivalent Circuit Diagram
Table 1. THAT 1606/1646 pin assignments
1. For complete details of OutSmarts, see Hebert, Gary K., "An Improved Balanced, Floating Output Driver IC", presented at the 108th AES Convention, February 2000.
Protected under US Patents numbers 4,979,218 and 6,316,970. Additional patents pending. THAT and OutSmarts are registered trademarks of THAT Corporation.
THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA
Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com
Copyright © 2015, THAT Corporation; Document 600078 Rev. 07
