ST X-NUCLEO-IKA01A1 User manual

Chipsmall Limited consists of a professional team with an average of over 10 year of expertise in the distribution
of electronic components. Based in Hongkong, we have already established firm and mutual-benefit business
relationships with customers from,Europe,America and south Asia,supplying obsolete and hard-to-find components
to meet their specific needs.
With the principle of “Quality Parts,Customers Priority,Honest Operation,and Considerate Service”,our business
mainly focus on the distribution of electronic components. Line cards we deal with include
Microchip,ALPS,ROHM,Xilinx,Pulse,ON,Everlight and Freescale. Main products comprise
IC,Modules,Potentiometer,IC Socket,Relay,Connector.Our parts cover such applications as commercial,industrial,
and automotives areas.
We are looking forward to setting up business relationship with you and hope to provide you with the best service
and solution. Let us make a better world for our industry!
Contact us
Tel: [phone] Fax: [phone]
Email & Skype: [email protected]om Web: www.chipsmall.com
Address: A1208, Overseas Decoration Building, #122 Zhenhua RD., Futian, Shenzhen, China
  

October 2015 DocID028405 Rev 1 1/28
28
UM1955
User manual
Getting started with the multifunctional expansion board based on
operational amplifiers for STM32 Nucleo
Introduction
The X-NUCLEO-IKA01A1 is a multifunctional expansion board based on operational
amplifiers. It provides an easy-to-use and affordable solution for different multifunctional use
cases with your STM32 Nucleo board. The X-NUCLEO-IKA01A1 is compatible with the
Arduino™ UNO R3 connector, and supports the addition of other boards that can be
stacked for enhanced applications with an STM32 Nucleo expansion board. It can be used
as a analog front-end by conditioning signals as an actuator to drive LED or coils, or in a
comparator architecture. Thanks to its current-sensing configuration, it allows current
measurement of any device that has a USB port. For this configuration and the
instrumentation amplifier configuration, a highly accurate operational amplifier (TSZ124) is
used. The expansion board also contains Nanopower (TSU104) and Micropower (TSV734)
operational amplifiers for mobile applications.
This user manual describes how to use the predefined configurations of the X-NUCLEO-
IKA01A1 expansion board:
•Instrumentation amplifier structure
•Current sensing with or without USB port
•Photodiode/UV current sensing
•Buffer
•Full wave rectifier
•Constant current LED driver
•Window comparator
The expansion board is also equipped with one prototyping area is powered through the
Arduino UNO R3 connectors.
Figure 1. X-NUCLEO-IKA01A1 multifunctional expansion board
www.st.com

Contents UM1955
2/28 DocID028405 Rev 1
Contents
1 Instrumentation amplifier configuration . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 How to set up the board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Theoretical output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Software and measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Current sensing configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 How to set up the board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3 Theoretical output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4 Software and measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 Buffer configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 How to set up the board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Theoretical output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4 Full wave rectifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1 Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2 How to set up the board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.3 Theoretical output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.4 Measurement example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5 Photodiode/UV sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1 Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
5.2 How to set up the expansion board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
5.3 Measurement example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
5.4 Additional possible use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6 LED driver configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.1 Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.2 How to set up the board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7 Window comparator configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

DocID028405 Rev 1 3/28
UM1955 Contents
28
7.1 Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.2 How to set up the board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.3 Theoretical output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8 Prototyping area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
9 Scenario examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1 Current sensing: motor outside of standard operation . . . . . . . . . . . . . . . 18
9.2 Strain gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.3 Electromyogram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.4 Body detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
10 Operational amplifiers on the expansion board . . . . . . . . . . . . . . . . . . 20
11 Schematic diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
12 Bill of material (BOM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
13 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Instrumentation amplifier configuration UM1955
4/28 DocID028405 Rev 1
1 Instrumentation amplifier configuration
The instrumentation amplifier configuration allows you to amplify a differential signal without
impacting it thanks to the high impedance of operational amplifier input stage. Moreover,
with the high accuracy resistors, this configuration features high rejection to common mode
voltage.
1.1 Schematic diagram
Figure 2 below depicts the circuit schematic of the instrumentation amplifier configuration.
Figure 2. Instrumentation amplifier configuration circuit schematic
1.2 How to set up the board
The instrumentation amplifier section of the expansion board includes several jumpers for
improved versatility. For this configuration, jumpers JP2, JP4 and JP5 must be mounted and
JP6 and JP7 should not be mounted. If the input signal is capacitive, a bias voltage needs to
be added. This configuration is possible by mounting jumpers JP6 and JP7. Once jumpers
have been set in the required configuration, the differential must be connected to pins Inst_n
and Inst_p.




9976=,37$N5N5*1'905S)&
1&
59
1&
5*1'$9UHI*1'76=,37&76=,37%*1'9UHI9UHI05S)&N5N5N5N5Q)&N5N5S)&

-3

-39-3

-3

-3,QVWBQ5JDLQBD5JDLQBE,QVWBS73N5J9EXV*1',2,2,2,2(6'(6'$/&/6&73*1'*63*',

DocID028405 Rev 1 5/28
UM1955 Instrumentation amplifier configuration
28
1.3 Theoretical output
The theoretical output voltage is defined by the following formula:
Equation 1
The operational amplifiers used for this configuration are used with a 5 V power supply.
Thus in order to obtain a range limited to 3.3 V to avoid any damage on the microcontroller
side, a divider bridge has been implemented. This additional structure is recognizable by the
last term in the above formula (composed of R37 and R38). Thanks to this structure, a DC 5
V output voltage is reduced to 3.2 V.
The gain of this instrumentation amplifier structure is defined by:
Equation 2
Note that it is also possible to increase the gain of the configuration by adding an external
resistor on the Rgain_a and Rgain_b pins. When an external resistor is used to change the
gain, jumper JP2 must be unmounted.
With this circuitry, the maximum frequency of the input signal is 850 Hz based on the op-
amp GBP and the circuit gain.
Equation 3
The factor 10 is taken in order to take margin and to properly amplify the signals at the
maximum frequency.
1.4 Software and measurements
The output voltage of the instrumentation amplifier is connected to the pin A1 of the Arduino
UNO R3 connector. The X-CUBE-ANALOG1 software available on www.st.com allows
users to measure this voltage.

Current sensing configuration UM1955
6/28 DocID028405 Rev 1
2 Current sensing configuration
The current sensing configuration allows monitoring of the current that is consumed by an
application. On this expansion board, the operational amplifier is set to a high-side current
sensing structure. This means that the current is measured close to the supply voltage, thus
before the application. Figure 3 illustrates this concept.
Figure 3. High-side current sensing application principle
2.1 Schematic diagram
Figure 4, shows the circuit schematic of the current sensing configuration.
Figure 4. Current sensing configuration circuit schematic
N5I5J
P
5V$Q)&I*1'76=,37'*1'N5I5JN5N5S)&Q)&I,LQ,RXW'XVE*1'05Q)&9EXV''*1'-86%$9EXV'','*1'-0LFUR86%*63*',

DocID028405 Rev 1 7/28
UM1955 Current sensing configuration
28
2.2 How to set up the board
With this expansion board, users can measure the current of a USB-powered device or any
5 V application. It is important not to go beyond 5 V in order to avoid operational amplifier
damage. To help protect the circuit, an ESDAULC6-1U2 unidirectional ESD protection
device has been implemented.
Monitoring USB-powered device current: connect the charger (wall adapter or PC) to the
Micro-USB port. Then connect the bottom USB port to the required device.
Monitoring other application current: it is also possible to measure the current of
applications that are not USB powered. The power supply voltage should be connected to
I
in
, and I
out
should be connected to the power supply voltage pin of the application.
2.3 Theoretical output
The output voltage of the operational amplifier is proportional to the measured current, as
the following formula illustrates:
Equation 4
Therefore,
Equation 5
Similar to the instrumentation amplifier configuration, the operational amplifier for this
configuration is used with a 5 V power supply voltage. Thus, in order to obtain a range
limited to 3.3 V avoid damage on the microcontroller side, a divider bridge has been added.
This additional structure is recognizable by the last term in the above formula (composed by
R30 and R39). Thanks to this structure, a DC 5 V output voltage is reduced to a 3.2 V.
Note that the maximum frequency of this circuit is limited to 330 Hz based on operational
amplifier GBP and the circuit gain.
Equation 6

Current sensing configuration UM1955
8/28 DocID028405 Rev 1
2.4 Software and measurements
The output voltage of the instrumentation amplifier is connected to pin A2 of the Arduino
UNO R3 connector. The X-CUBE-ANALOG1 software, available on www.st.com, allows
users to measure this voltage.
Note that with this predefined configuration, it is possible to measure up to 2.08 A. If a
higher current is drawn through the application, the operational amplifier will be saturated
and thus its output voltage will not reflect the real current.
The following table shows the correspondence between measured current, output voltage
and LSB on ADC.
Table 1. Output parameter values for current sensing configuration
Current (A) Output voltage of
operational amplifier
Voltage after divider
bridge (at A4 node)
Number of LSBs with
12-bit ADC
0.1 240 mV 159 mV 197
0.2 480 mV 317 mV 394
0.5 1.20 V 793 mV 985
1.0 2.40 V 1.586 V 1969
1.5 3.60 V 2.380 V 2954
2.0 4.80 V 3.173 V 3938

DocID028405 Rev 1 9/28
UM1955 Buffer configuration
28
3 Buffer configuration
The buffer configuration allows users to connect a high output impedance circuit to a low
input impedance circuit without disturbing the signal. This function is possible thanks to the
high impedance of the operational amplifier input stage and the operational amplifier output
capabilities. The operational amplifier used for this configuration is the TSV734, which has a
minimum output current of 40 mA.
3.1 How to set up the board
In order to use the buffer configuration on the expansion board, users simply connect their
signal to the “in” pin on the buffer section of the board. The output signal can be retrieved on
the “out” pin in the same board section. The output voltage of the operational amplifier is not
intended to be connected to any microcontroller input on the expansion board since this
configuration is most often used before another circuit.
3.2 Theoretical output
The output voltage of the operational amplifier is equal to its input voltage:
V
out
=V
in
Note that this equation is correct as long as the input voltage stays between 0 V and 3.3 V
(the power supply voltage of the operational amplifier).