that1570 THAT Corporation, that1570 Datasheet - Page 10

• Manufacturer Part Number: that1570
• Description: Low-noise, Differential Audio Preamplifier Ic
• Manufacturer: THAT Corporation

Document 600132 Rev 01
pad on its bottom. This pad is connected internally
to V
the PCB as shown in Figures 9 and 10. Five thermal
vias should be arranged in the configuration shown
in Figure 10 to provide uniform heat distribution
between the top layer of the PCB to the bottom layer.
THAT1570, stray capacitance to ground or power
planes results in higher gains at high frequencies.
This compromises common-mode rejection at high
frequencies and, in extreme cases, can even lead to
oscillation. Take care to avoid ground and power
planes under and near R
pins and traces.
pickup from power supply currents, which often take
The 1570 QFN package includes a metal thermal
For current feedback amplifiers such as the
The input signal lines are susceptible to magnetic
EE
, and it should be soldered to a thermal pad on
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THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA
A
, R
B
Copyright © 2009, THAT Corporation; All rights reserved.
, R
G
, their associated
PCB Layout Information
Page 10 of 12
the form of half-wave rectified versions of the signal.
Voltage fluctuations on the supply lines can couple
capacitively as well. For this reason, take care not to
run power and input signal lines close and/or paral-
lel to each other.
Minimizing RFI
the input of all the applications schematics should be
located as close as possible to the input connector,
and the ground ends of C
possible to the chassis. When using the additional
RFI protection network C
phantom power circuits Fig. 7 and 8), these compo-
nents should be located as close as possible to the
1570’s input pins.
To minimize RF pickup, the C
Differential Audio Preamplifier IC
1
and C
6
~ C
THAT1570 Low-Noise
2
1
8
tied as closely as
~ C
(shown in the
3
network at