Texas Instruments SoundPlus INA1651EVM User Manual
User's Guide
SBOU212–September 2018
INA1651EVM SoundPlus™ High Common-Mode Rejection
Line Receiver Evaluation Module
This user's guide contains information for the INA1651 as well as support documentation for the INA1651
evaluation module (EVM). Included are the performance specifications, set-up procedure, modifications,
measured data, printed circuit board (PCB) layout, schematic, and bill of materials of the INA1651EVM.
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Figure 1. INA1651 SoundPlus™ Evaluation Module (EVM)
INA1651EVM SoundPlus™ High Common-Mode Rejection Line Receiver
Copyright © 2018, Texas Instruments Incorporated
Evaluation Module
1
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Contents
1 Introduction ................................................................................................................... 3
2 EVM Measured Performance Summary.................................................................................. 3
3 Modifications.................................................................................................................. 3
3.1 AC-Coupled Corner Frequency................................................................................... 4
3.2 Filtering the VMID (IN) Pin......................................................................................... 4
3.3 Start-Up Time ....................................................................................................... 5
3.4 Increasing the Common-Mode Input Impedance............................................................... 5
4 Test Setup and Results..................................................................................................... 6
4.1 Power Supply Connections........................................................................................ 6
4.2 Input Connections .................................................................................................. 6
4.3 Output Connections ................................................................................................ 6
4.4 REF A and COM A ................................................................................................. 7
4.5 Common-Mode Rejection Ratio................................................................................... 9
4.6 THD+N vs. Amplitude.............................................................................................. 9
4.7 THD+N vs. Frequency............................................................................................ 10
4.8 Fast-Fourier Transform (FFT) ................................................................................... 11
5 Board Layout................................................................................................................ 12
5.1 Layout............................................................................................................... 12
6 Schematic, Bill of Materials, and Reference............................................................................ 14
6.1 Schematic .......................................................................................................... 14
6.2 Bill of Materials .................................................................................................... 15
6.3 Reference .......................................................................................................... 15
1 INA1651 SoundPlus™ Evaluation Module (EVM)....................................................................... 1
2 Simplified INA1651EVM Schematic....................................................................................... 3
3 RC Charging Rate........................................................................................................... 5
4 J8 Connection for Single-Supply Operation.............................................................................. 7
5 J8 Connection for Dual Supply Operation................................................................................ 8
6 Common-Mode Rejection Ratio (CMRR) Measurement ±15-V Supplies, 1-V
7 THD+N vs. Amplitude Measurement ±15-V Supplies, 1-kHz Output, 22-kHz MBW................................ 9
8 THD+N vs. Frequency Measurement with 1 V
9 THD+N vs. Frequency Measurement With 10 V
10 FFT Measurement 1 kHz, 10-V
11 Top Layer PCB Layout .................................................................................................... 12
12 Bottom Layer PCB Layout ................................................................................................ 13
13 Schematic ................................................................................................................... 14
1 INA1651EVM Measured Performance Summary ....................................................................... 3
2 Final Capacitor Voltage..................................................................................................... 5
3 INA1651EVM Bill of Materials ............................................................................................ 15
Trademarks
SoundPlus is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
List of Figures
Input, 90-kHz MBW........... 9
RMS
Output ±15-V Supplies, 1-V
RMS
Output ±15-V Supplies, 10-V
RMS
Output .............................................................................. 11
RMS
Output, 90-kHz MBW...... 10
RMS
Output, 90-kHz MBW .. 10
RMS
List of Tables
2
INA1651EVM SoundPlus™ High Common-Mode Rejection Line Receiver
Evaluation Module
Copyright © 2018, Texas Instruments Incorporated
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+
±
+
±
VCC
VEE
IN+ A
COM A
IN- A
OUT A
VREF A
VMID (IN)
VMID (OUT)
VCC VEE
VCC VEE
R4
C9
C6 C11
R1
R5
C7
+ INPUT
- INPUT
C10
J8
R2
C8
R3
OUTPUT
Copyright © 2018, Texas Instruments Incorporated
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1 Introduction
The INA1651 is a high common-mode rejection audio line receiver from the SoundPlus line of audio
amplifier products from Texas Instruments. For a full list of electrical characteristics of the INA1651,
please refer to the INA1651 product data sheet (INA165x SoundPlus™ High Common-Mode Rejection
Line Receivers).
2 EVM Measured Performance Summary
A summary of the INA1651EVM performance specifications is provided in Table 1. Specifications are
given for a supply voltage of VS= ±15 V at an ambient temperature of 25°C, unless otherwise noted.
Table 1. INA1651EVM Measured Performance Summary
Specification Test Conditions Measured Performance
Common-Mode Rejection Ratio (CMRR) VIN= 1 V
THD+N at 1 kHz VIN= 22 dBu –121 dB
Second Harmonic V
Start-Up Time 1.5 s
3 Modifications
This EVM is designed to provide access to the features of and measure the performance of the INA1651.
Modifications of the INA1651EVM can be made and include; adjusting the ac-coupled corner frequency,
filtering the VMID (IN) pin, adjusting the start-up time, and increasing the common-mode input impedance.
A simplified schematic of the INA1651EVM is displayed in Figure 2. For a full schematic of the
INA1651EVM, see Figure 13.
OUT
= 10 V
at 1 kHz –90 dB
RMS
, F = 1 kHz –142.86 dBc
RMS
Introduction
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Figure 2. Simplified INA1651EVM Schematic
Copyright © 2018, Texas Instruments Incorporated
INA1651EVM SoundPlus™ High Common-Mode Rejection Line Receiver
Evaluation Module
3
0
f
1
c _ VMID
2 250k C
1
S u : u
R
3
Attenuation
R R
2 3
8
f
1
c _out
2 (R R ) C
2 3
S u u
n
f
1
c _in
C R
7 i
S u u
Modifications
3.1 AC-Coupled Corner Frequency
Capacitors C7 and C9 provide the option to ac couple the input of the INA1651 and capacitor C8 provides
the option to ac couple the output of the INA1651. Equation 1 calculates the high pass corner frequency of
input A and input B due to capacitors, C7 and C9 on the input.
where
• C7= C
• RINis the differential input impedance of the INA1651 (1)
9
Equation 2 calculates the high-pass corner frequency due to capacitor C8 and resistors R2 and R3 on the
output.
Resistors R2 and R3 form a voltage divider on the output of the INA1651 and will attenuate the output
signal. Equation 3 calculates the attenuation on the INA1651 output.
3.2 Filtering the VMID (IN) Pin
Capacitor C10 provides an option to filter the input to the internal reference buffer, VMID (IN). Equation 4
calculates the cut-off frequency due to C10.
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(2)
(3)
(4)
4
INA1651EVM SoundPlus™ High Common-Mode Rejection Line Receiver
Evaluation Module
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Z CC
1
V V 100 mV
³ +
Time Constants (WRC)
Final Capacitor Voltage ()
0 1 2 3 4 5 6
0
10
20
30
40
50
60
70
80
90
100
D001
RC 10
250k CW : u
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3.3 Start-Up Time
Capacitor C10 increases the settling time of the VMID (OUT) pin due to the resistance of the internal
voltage divider for VMID (IN) and C10 creating an RC time constant. Equation 5 calculates one RC time
constant.
Figure 3 displays the rate at which an RC circuit charges to its final value. Notice at one time constant, the
voltage across the capacitor is at 63.2% of its final value.
Modifications
(5)
Figure 3. RC Charging Rate
Table 2 shows the final capacitor voltage at multiple time constants.
To decrease the settling time of the VMID (OUT) voltage the Zener diode, D1, can be populated. The
Zener voltage of the diode should be chosen to be greater than 100 mV more than one half of the supply
voltage. Equation 6 calculates the recommended Zener voltage of the diode (Vz). Note that due to the
leakage current of the Zener diode interacting with the internal voltage divider resistance an error may be
seen on the VMID (OUT) pin.
3.4 Increasing the Common-Mode Input Impedance
The high CMRR of many line receivers can be degraded by source impedance mismatches in the system.
Resistor R4 provides an option to increase the common-mode input impedance of the INA1651 to reduce
the effects of source impedance mismatch. For an explanation on the effects of increasing the commonmode input impedance, refer to section 8.1.2 of the INA1651 product data sheet (SBOS818).
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Table 2. Final Capacitor Voltage
Time Constant (τRC) Final Capacitor Voltage (%)
1 63.2%
2 86.4%
3 95.0%
4 98.1%
5 99.3%
6 99.7%
INA1651EVM SoundPlus™ High Common-Mode Rejection Line Receiver
Copyright © 2018, Texas Instruments Incorporated
(6)
5
Evaluation Module
Test Setup and Results
4 Test Setup and Results
This section describes how to properly connect, set up, and use the INA1651EVM. This section also
includes measured data of the INA1651EVM to display typical performance of the INA1651EVM.
Measurements include:
• Common-mode rejection ratio (CMRR)
• THD+N vs. Amplitude
• THD+N vs. Frequency
• Fast-Fourier Transform (FFT)
The THD+N vs. Amplitude, THD+N vs. Frequency, and FFT measurements were taken using an Audio
Precision APx555. All measurements used ±15-V supplies at an ambient temperature of 25 °C.
4.1 Power Supply Connections
The power supply connections for the INA1651EVM are provided through the use of the banana jacks or
test points located at the top of the EVM. The positive power supply connections are labeled as VCC, the
negative power supply connections are labeled as VEE, and the ground connections are labeled as GND.
For the minimum and maximum supply voltages of the INA1651EVM, refer to the INA1651 product data
sheet (SBOS818).
4.2 Input Connections
Input signals for the input are applied to the INA1651EVM through the use of the female XLR connector
J1 or terminal block J3. The female XLR connector follows the standard female XLR pin out with pin 1
connected to ground, pin 2 connected to the positive input, and pin 3 connected to the negative input. The
terminal block connections are labeled as +IN for the positive input, -IN for the negative input, and GND
for the ground connection.
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4.3 Output Connections
The right and left channel output connections are provided through BNC connectors, J7 and J8, RCA
jacks, J9 and J10, and test points TP3 and TP5, respectively. The right channel outputs are labeled as
RIGHT OUTPUT and the left channel outputs are labeled as LEFT OUTPUT. The RCA jacks provide a
connection to a load while the BNC connectors and test points provide a way to measure the performance
of the INA1651 while a load is connected.
6
INA1651EVM SoundPlus™ High Common-Mode Rejection Line Receiver
Evaluation Module
Copyright © 2018, Texas Instruments Incorporated
SBOU212–September 2018
Submit Documentation Feedback
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