1240P08-U THAT Corporation, 1240P08-U Datasheet - Page 5

• Manufacturer Part Number: 1240P08-U
• Description: Difference Amplifiers Balanced Input Line Receiver 0dB DIP-8
• Manufacturer: THAT Corporation

Specifications of 1240P08-U

• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: 0 C
• Mounting Style: Through Hole
• Operating Temperature Range: 0 C to + 85 C
• Output Current: +/- 25 mA
• Operating Supply Voltage: +/- 18 V
• Package / Case: DIP-8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

THAT 1240 Series
Balanced Line Receiver ICs
maximum common mode input signal for the 1240 is
(2V
the 1243, these figures are (2.4V
(2.4V
(3V
rails, the 1240 will accept up to ~26 V in either
direction. As an ac signal, this is 52 V peak-peak,
18.4 V rms, or +27.5 dBu. With the same supply
rails, the 1243 will accept up to ~31 V in either
direction. As an ac signal, this is 62 V peak-peak,
21.9 V rms, or +29 dBu. With the same supply rails,
the 1246 will accept up to ~39 V in either direction.
As an ac signal, this is 78 V peak-peak, 27.6 V rms,
or +31 dBu.
common-mode signals combine. The maximum
signal that can be accommodated will depend on the
superposition of both differential and common-mode
limitations.
Output Considerations
supplying 25 mA into a short circuit. While they will
survive a short, power dissipation will rise dramati-
cally if the output is shorted. Junction temperature
In+
In-
CC
CC
Following the same reasoning as above, the
Therefore, for common-mode signals and ±15 V
Of course, in the real world, differential and
The 1240-series devices are typically capable of
EE
- 6) V, and (3V
- 4) V, and the minimum is (2V
Figure 3. Representative input protection circuit
47p
C3
In+
+ 4.8) V.
Figure 4. RFI and supply bypassing
V
EE
470p
C4
470p
C5
V
CC
EE
For the 1246, these figures are
R
3
+ 6) V.
Tel: [phone]; Fax: [phone]; Web: www.thatcorp.com
100n
THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA
2
3
C2
100n
C1
In-
In+
V
V
V
R
CC
CC
V
EE
+
-
7
4
EE
4
Sens
Ref
V
1
5
Out
EE
CC
THAT1246/1243/1240
V
U1
CC
EE
6
- 4.8) V, and
Copyright © 2008, THAT Corporation
+ 4) V. For
Ref
Out
Page 5 of 8
must be kept under 125 ºC to maintain the devices’
specifications.
load capacitance.
Power Supply Considerations
tive to the power supply, but they do contain wide
bandwidth opamps. Accordingly, small local bypass
capacitors should be located within a few inches of
the supply pins on these parts, as shown in Figure 4.
Selecting a Gain Variation
structures to suit different applications. The 1246 is
customarily configured for -6 dB gain, but by revers-
ing the resistor connections, can also be configured
for +6 dB. The 1243 is most often configured for
-3 dB gain, but can also be configured for +3 dB.
The choice of input gain is determined by the input
voltage range to be accommodated, and the power
supply voltages used within the circuit.
ratio, the input stage should be selected and config-
ured for the highest possible gain that will ensure
that maximum-level input signals will not clip the
input stage or succeeding stages. For example, with
±18 V supply rails, the 1240-series parts have a
maximum output signal swing of +23 dBu. In order
to
maximum gain for the stage is -1 dB. With ±15 V
supply rails, the maximum output signal swing is
~+21.1 dBu; here, -3 dB is the maximum gain. In
each case, a 1243 configured for -3 dB gain is the
ideal choice.
provide enough headroom at its output to support a
+24 dBu input signal.
-6 dB gain) will increase noise, thus reducing
dynamic range, by attenuating the input signal more
than necessary to support a +24 dBu input.
THAT recommends the -3 dB input configuration
possible only with the 1243 in order to preserve
dynamic range within a reasonable range of power
supply voltages and external headroom limits.
accommodate +24
These devices are stable with up to 300 pF of
The 1240-series parts are not particularly sensi-
The three different parts offer different gain
To minimize noise and maximize signal-to-noise
In fact, for most professional audio applications,
+In
-In
2
3
In+
In-
Figure 5. Zero dB line receiver
The 1240 (0dB gain only) will not
9k
9k
4
7
V
V
CC
EE
The 1246 (configured for
dBu
Document 600035 Rev 04
9k
9k
Sense
input signals,
U1
1240
Vout
Ref
5
6
1
Output
the