THAT1510 ETC, THAT1510 Datasheet - Page 5

• Manufacturer Part Number: THAT1510
• Description: Low Noise/ High Performance Microphone Preamplifier IC
• Manufacturer: ETC

600031 Rev. 7/23/02
Preliminary Information
tempco of the internal resistors (±20 ppm/°C typi-
cal).
Noise Performance
significantly lower noise at low gains than similar IC
microphone preamps. At zero dB gain, equivalent in-
put noise of the THAT 1510 is 55 nV/ÖHz, nearly
6 dB better than competitive IC designs.
usual topology of the THAT 1512 results in an equiv-
alent input noise of 34 nV/ÖHz at zero dB gain, which
makes it comparable to some of the better discrete
designs currently available. At 1 kHz, the equivalent
input noise for both devices is 1 nV/ÖHz at 60 dB
gain.
Inputs
V+ and V- of the THAT 1510/1512. These diodes re-
duce the likelihood of accidental ESD/EOS damage to
the IC. Other diodes across the base-emitter junc-
tions of the input transistors prevent reverse bias of
these junctions and consequent degradation of their
noise performance.
ing, so a dc bias connection is required to maintain
the inputs within the IC's input common-mode range.
Thoughtful design results in these devices having
Protection diodes are employed at all pins except
The inputs of the THAT 1510 and1512's are float-
In+
In-
6k8
C1
470p
C2
470p
R6
+48V
THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: [phone]; Fax: [phone]; Web: www.thatcorp.com
47p
C3
R5
6k8
47u
47u
C5
C4
Figure 4. Typical 1510 / 1512 Circuit with Phantom Power
51R
51R
R3
R4
R1
1k
R2
1k
The un-
1N5818
1N5818
1N757
D1
D4
D3
Four different schemes are shown in Figures 2, 3, 4,
and 5. Note that the values of R1 and R2 in these fig-
ures should be kept small to minimize pickup of un-
wanted noise and interference. A value of 1 kW is
often used, since some microphones require a differ-
ential input impedance of this magnitude. Unfortu-
nately, one would usually desire a significantly higher
common mode input impedance to minimize the
common mode degradation caused by unbalanced
source impedances.
which allows higher common mode input impedance
while maintaining a lower differential source imped-
ance.
Reference Terminal
put signal, and is normally connected to analog
ground. If necessary, the "Ref" pin can be used for
offset correction or DC level shifting. A non-zero ref-
erence source resistance will reduce the IC's com-
mon-mode
10 kW/R
Phantom Power
phones. A phantom power circuit is shown in Fig-
ure 4.
protect the THAT 1510/1512 from transient voltages
1N757
D5
1N5818
D6
1N5818
D2
The "Ref" pin provides the reference for the out-
Phantom power is required for condensor micro-
REF
Diodes D1 through D6 are necessary to
.
rejection
RG
2
8
1
3
-In
RG2
RG1
+In
Figure 5 shows a technique
-15
(CMR)
V-
+15
V+
100n
Ref
C9
100n
C6
Out
by
THAT 1510
U1
6
the
Out
ratio
Page 5
of