THAT1570/THAT5171
Digitally-Controlled Microphone Preamplifier
Demo Board
User's Guide
Document 600134 Rev 03
Contents
Features/Specifications....................................................................................... 3
Overview ............................................................................................................ 4
Connections ....................................................................................................... 5
Hardware Set-up ................................................................................................. 5
Software Set-up ................................................................................................... 6
Operation ........................................................................................................... 7
Jumper Options ................................................................................................. 7
Appendix A - Schematic...................................................................................... 9
Appendix B - Bill of Materials............................................................................. 10
Appendix C - PCB Layout .................................................................................. 12
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; All rights reserved.
Document 600134 Rev 03
Page 2 of 16
THAT 1570/5171-DEMO User’s Guide
Packing List
(1) THAT1570/5171 DEMO Board PCB Assembly
(1) USB Cable
If you are missing any of the above items please contact us at
support@thatcorp.com.
FCC Warning
This device is only intended for laboratory test environments. It may radiate radio
frequency energy and has not been tested for compliance with subpart J of part
15 of the FCC regulations. Operation of this device in other environments may
cause interference with radio communications.
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; All rights reserved.
Document 600134 Rev 03
Page 3 of 16
THAT 1570/5171-DEMO User’s Guide
Features
•
•
•
•
•
•
•
“Combo” XLR/TRS balanced input with switchable 48V phantom power
Balanced audio output on XLR and TRS connectors
Supports pro audio signal levels: +21dBu input / output
Gain (measured input to output) adjustable in 1dB steps: 0dB, and 8-63dB
USB 1.1 and USB 2.0 compatible control port
Graphical user interface software for controlling 5171 parameters
Prototyping area
Description
The THAT Digitally-Controlled Mic Preamp Demo Board allows developers to
evaluate the performance of the THAT1570 / THAT5171 chipset. The demo
board provides a balanced audio input on a Neutrik “combo” connector with 48V
phantom power, and a balanced audio output on XLR and ¼” TRS connectors.
The supplied graphical user interface (GUI) controls all functions in the 5171 chip
via USB. A prototyping area is available for adding or modifying circuitry.
Specifications
Parameter
Power Supply Voltage
Maximum
±
Input Level
(V+ /V- = 15V)
Maximum
±
Differential Output Level
(V+ /V- = 15V)
Gain (input to output)
Gain error (all settings)
Total Harmonic Distortion
(V
OUT
= +16dBu (5V
RMS
); R
L
= 10kΩ;
C
L
= 10 pF; f = 1kHz; BW = 22 kHz)
Equivalent Input Noise
(main output)
Symbol
V+ - V-
v
in-BAL
V
OUT
A
dB
A
err
THD
Typical
±
15
+21
+21
0
8 to 63 in 1dB steps
±
0.15
0.0003 (0dB gain)
0.0003 (20dB gain)
0.0008 (40dB gain)
0.006 (60dB gain)
1.65 (60dB gain)
1.9 (40dB gain)
5.0 (20dB gain)
22.9 (0dB gain)
1.65 (60dB gain)
1.9 (40dB gain)
4.8 (20dB gain)
20 (0dB gain)
23 (V+ supply)
23 (V- supply)
0.5 (+5V supply)
Units
V
dBu
dBu
dB
dB
%
EIN
nV/√Hz
Equivalent Input Noise
(1570 output)
EIN
nV/√Hz
Supply Current
I
CC
; -I
EE
, I
DD
mA
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; All rights reserved.
Document 600134 Rev 03
Page 4 of 16
THAT 1570/5171-DEMO User’s Guide
THAT1570 / THAT5171 Overview
The THAT1570 and THAT5171 ICs enable digitally-controlled microphone
preamplifier applications with exceptionally high performance. Operating on
maximum +/-17V supplies, the chipset accepts pro audio input levels (+22dBu
max) without an input pad. Gain is adjustable to 5.6dB, and 13.6dB to 68.6dB in
1dB increments (a 5.6dB attenuator at the output offsets the overall gain range to
0dB, and 8-63dB). The 5171’s built-in zero-crossing detector and other patent-
pending techniques for reducing zipper noise enable very smooth and silent gain
changes. A differential servo reduces output offsets to less than 1.5mV. Four
general purpose outputs on the 5171 can be connected to a variety of peripheral
functions, e.g. an input pad, phantom power switch, signal routing switches,
LEDs, etc. The 5171’s addressable SPI interface supports read-back. By separat-
ing the analog mic pre amp front end (THAT1570) from the digital functions and
switched resistor ladder (THAT5171), each IC is optimized for high performance.
The THAT1570 is fabricated using THAT’s complementary dielectric isolation
process and precision laser-trimmed Si-Chrome thin film resistors, yielding
extremely high performance. The THAT5171 is fabricated using a high-voltage
CMOS process, with proprietary techniques for reducing FET switching glitches.
Packaged in 4x4mm QFN16 and 7x7mm QFN32 packages respectively, the
THAT1570 and THAT5171 require very little PCB area.
Block Diagram
CHAS
+48 V
+15 V
GND
- 15 V
+5 V
Power Supply Inputs
+3.3V
REG
+5V
Reset
Switch
RST
TRC
BSY
Vdd
USB
USB
Interface
MUX
Ext
SPI
Conn
U1
T H AT
5171
Con trol
Logic
Vcc
Vcc
Servo
+
-
+
-
Vee
R esistor
N etwork
with FET
Switches
IN2
IN1
Rg1
Vee
SOUT2
SOUT1
SCAP1
SCAP2
DOUT
GPO3
GPO2
GPO1
GPO0
DIN
CS
SCLK
DGnd
LEDs
AGnd
Rg2
SPI Bus
Mic/Line
Input
U2
THAT
1570
Balanced
Output
Driver
Balanced
Output
RFI
Protection
Phantom
Power
Fault
Protection
RFI
Protection
OUTPUT
SECTION
INPUT SECTION
Figure 1 -- Block Diagram of the THAT 1570/5171 Demo Board
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; All rights reserved.
Document 600134 Rev 03
Page 5 of 16
THAT 1570/5171-DEMO User’s Guide
Connections
Power
The USB interface runs on USB bus power, but the rest of the demo board
requires an external power supply. +/-15 V (maximum +/-17V) supplies the
analog circuitry. +48V phantom power is input (not generated on the board) and
switched on and off via the on-board Phantom Power switch. Note that the ground
return for +48V phantom power is via the CHAS (chassis ground) connector. The
+5V input is regulated on board to 3.3V and supplies the digital logic.
Audio Input
The Neutrik combo connector accepts an XLR or ¼” TRS cable. Maximum input
signal level is +21dBu with +/-15V supplies, or +22dBu with +/-17V supplies.
The 1/4” TRS signal path includes a 20dB pad in order to support very high line
levels.
Audio Output
Separate XLR and ¼” TRS connectors are wired in parallel. Maximum output
signal level is +21dBu with +/-15V supplies, or +22dBu with +/-17V supplies.
The differential attenuator/output buffer (U3) adds a small amount of noise and
distortion to the signal and it is therefore recommended that test points TP1-TP3
be used to measure performance of the 1570/5171 ICs.
USB
A PC must be plugged into the demo board via USB in order to control parame-
ters in the 5171 (e.g. gain). Take care not to hot plug the demo board while the
GUI software is running as this will often crash the Windows drivers.
General Purpose Outputs (GPO)
The GPO3:0 pins are connected to header J12. J12 is conveniently located near
the prototyping area, so the user can easily connect optional circuitry to them.
Note that the GPO pins are also connected to LEDs, D1-D4, and pull up and pull
down resistors which set the 5171 device address during reset. Consideration
must be given to how any application circuitry that is added interacts with these
other functions.
Hardware Set-up
1. Connect a power supply to the V+, V-, +5V, +48V, CHAS and GND
connectors. Do not turn on power yet.
2. Plug in the audio input and output
3. Attach a USB cable to the demo board, but do not plug it into the PC yet
4. Turn on the power supply
5. Turn on phantom power to microphone (if appropriate)
6. Plug USB cable into PC. Windows should go through its procedure for discov-
ering the new USB peripheral and loading its driver.
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; All rights reserved.
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