THAT1430 That, THAT1430 Datasheet - Page 6

• Manufacturer Part Number: THAT1430
• Description: (THAT1420 / THAT1430) Balanced Line Drivers
• Manufacturer: That

i
Page 6
tual worst case peak level for various types of music
and speech will be flat out to 5kHz, and roll off at
6dB/octave above this frequency. Thus the peak lev-
els at 20kHz will be 12dB below those at 5kHz.
rate and current drive. Since both outputs can swing
±11V, the V
20kHz, V
As a consequence,
Thus, driving this 40nF cable requires 28mA
(well within the 1420/1403’s capabilities). Figure 4
shows the most basic connection between the THAT
1420 and a typical line receiver (like the THAT
1243). The only external components that are abso-
lutely required are the local 100nF bypass capaci-
tors, and these could, in fact, be shared with another
nearby component. There are no common mode out-
put offset reduction capacitors, and the line driver’s
outputs are connected directly to their respective
=
500
Using these, we can calculate the required slew
dV
dt
100n
100n
In
=
ft
C4
C5
2
Peak
´
p
(
´
30
Peak
5 5
is 5.5V. Therefore,
.
4
3
pF
ft
V
In
Gnd
is actually 22V (below 5kHz), and at
´
+
Vee
Vcc
20
25
Vcc
THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Vee
Figure 5. Basic THAT 1430 application circuit with output common mode offset reduction
kHz
Tel: [phone]; Fax: [phone]; Web: www.thatcorp.com
Cap2
Cap1
pF
ft
+
=
Out-
25
Out+
U1
THAT1430
100n
0 69
.
C1
8
pF
ft
1
m
)
V
s
´
0 69
.
m
V
s
»
28
mA
Peak
1M0
R1
sense inputs. The outputs are also DC coupled to the
line receiver. If large common mode voltages are ex-
pected, the designer may choose to incorporate large,
non-polarized capacitors to isolate the THAT 1420’s
outputs.
circuit.
for common mode offset reduction. This IC is spe-
cially designed to allow common mode offset reduc-
tion with only a small resistor and capacitor, and is
ideal for new designs where space is at a premium.
Other considerations that apply to the THAT 1420
apply to the THAT 1430.
offset reduction, RFI protection and surge protection,
but these last two additions could be added to the
THAT 1430 as well. One should also note that the
THAT 1420 is pin-for-pin compatible with industry
standard line drivers.
dreds of feet in length without becoming unstable,
but attaching such a long cable can act as an antenna
(even for AM stations) which can pick up RFI and di-
rect it into the circuit. C3 and C8 are 100pF capaci-
Figure 5 shows the basic THAT 1430 applications
Figure 6 shows a THAT 1420 with common mode
These line drivers can easily drive cables hun-
2
3
This circuit includes external components
In-
In+
Vee
Vcc
Vcc
Vee
THAT1420/1430 Balanced Line Driver
Ref
Out
U2
THAT1243 or equiv.
C6
100n
C7
100n
6
Preliminary Information
Out