Electromagnetic Emission Summary for TriCore AUDO MAX

TriCore™ AudoMax Derivatives
TC1724, TC1728, TC1782,
TC1784, TC1791, TC1793,
TC1798
Elect ro ma gnetic E m is s ion Su m ma r y
AP 3219 3
Test Re po rt
V1.0 2012-02
Mic rocon t rolle rs
Edition 2012-02
Published by
Infineon Technologies AG
81726 Munich, Germany
© 2012 Infineon Technologies AG
All Rights Reserved.
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
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Test Report
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V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
Table of Contents
1
Introduction ........................................................................................................................................ 6
2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
Executive summary ........................................................................................................................... 7
Selected nets for emission comparison ............................................................................................... 7
Test procedure compliance .................................................................................................................. 7
General emission result ....................................................................................................................... 7
Conducted emission result ................................................................................................................... 7
Radiated emission result ...................................................................................................................... 8
PCB design recommendations ............................................................................................................. 8
Microcontroller configuration recommendations .................................................................................. 8
3
3.1
3.2
Emission measurement methods ..................................................................................................... 9
Conducted emission measurement...................................................................................................... 9
Radiated emission measurement....................................................................................................... 10
4
Emission limit curves ...................................................................................................................... 11
5
Microcontroller operation during test ............................................................................................ 13
6
6.1
6.1.1
6.1.2
6.1.3
6.2
6.2.1
6.2.2
6.2.3
6.3
6.3.1
6.3.2
6.3.3
6.4
6.4.1
6.4.2
6.4.3
6.5
6.5.1
6.5.2
6.5.3
6.6
6.6.1
6.6.2
6.6.3
6.7
6.7.1
6.7.2
6.7.3
Conducted emission measurement results .................................................................................. 14
Microcontroller TC1724 ...................................................................................................................... 14
TC1724: Probed nets ......................................................................................................................... 14
TC1724: Result summary .................................................................................................................. 14
TC1724: Conducted emission results ................................................................................................ 15
Microcontroller TC1728 ...................................................................................................................... 17
TC1728: Probed nets ......................................................................................................................... 17
TC1728: Result summary .................................................................................................................. 17
TC1728: Conducted emission results ................................................................................................ 18
Microcontroller TC1782 ...................................................................................................................... 20
TC1782: Probed nets ......................................................................................................................... 20
TC1782: Result summary .................................................................................................................. 20
TC1782: Conducted emission results ................................................................................................ 21
Microcontroller TC1784 ...................................................................................................................... 23
TC1784: Probed nets ......................................................................................................................... 23
TC1784: Result summary .................................................................................................................. 23
TC1784: Conducted emission results ................................................................................................ 24
Microcontroller TC1791 ...................................................................................................................... 26
TC1791: Probed nets ......................................................................................................................... 26
TC1791: Result summary .................................................................................................................. 26
TC1791: Conducted emission results ................................................................................................ 27
Microcontroller TC1793 ...................................................................................................................... 29
TC1793: Probed nets ......................................................................................................................... 29
TC1793: Result summary .................................................................................................................. 29
TC1793: Conducted emission results ................................................................................................ 30
Microcontroller TC1798 ...................................................................................................................... 32
TC1798: Probed nets ......................................................................................................................... 32
TC1798: Result summary .................................................................................................................. 32
TC1798: Conducted emission results ................................................................................................ 33
7
7.1
7.1.1
7.1.2
7.2
7.2.1
7.2.2
7.3
7.3.1
7.3.2
Radiated emission measurement results ...................................................................................... 35
Microcontroller TC1724 ...................................................................................................................... 35
TC1724: Radiated emission result summary ..................................................................................... 35
TC1724: Radiated emission result ..................................................................................................... 35
Microcontroller TC1728 ...................................................................................................................... 36
TC1728: Radiated emission result summary ..................................................................................... 36
TC1728: Radiated emission result ..................................................................................................... 36
Microcontroller TC1782 ...................................................................................................................... 37
TC1782: Radiated emission result summary ..................................................................................... 37
TC1782: Radiated emission result ..................................................................................................... 37
Test Report
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
7.4
7.4.1
7.4.2
7.5
7.5.1
7.5.2
7.6
7.6.1
7.6.2
7.7
7.7.1
7.7.2
Microcontroller TC1784 ...................................................................................................................... 38
TC1784: Radiated emission result summary ..................................................................................... 38
TC1784: Radiated emission result ..................................................................................................... 38
Microcontroller TC1791 ...................................................................................................................... 39
TC1791: Radiated emission result summary ..................................................................................... 39
TC1791: Radiated emission result ..................................................................................................... 39
Microcontroller TC1793 ...................................................................................................................... 40
TC1793: Radiated emission result summary ..................................................................................... 40
TC1793: Radiated emission result ..................................................................................................... 40
Microcontroller TC1798 ...................................................................................................................... 41
TC1798: Radiated emission result summary ..................................................................................... 41
TC1798: Radiated emission result ..................................................................................................... 41
8
8.1
8.2
8.3
Microcontroller configuration impact on emission ...................................................................... 42
Emission influence from exposed die pad ......................................................................................... 42
Emission influence from scaled pad drivers ....................................................................................... 43
Emission influence from clock frequency modulation ........................................................................ 45
9
References ........................................................................................................................................ 46
10
Abbreviations ................................................................................................................................... 47
Test Report
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
1
Introduction
This application note describes the electromagnetic emission (EME) behaviour of all Infineon’s AudoMax
microcontrollers. Table 1 lists their main EME-relevant design and functional features.

All microcontrollers are fabricated in a 90 nm CMOS process.

The lead-frame packages (QFP) offer a centered “e-pad” which must be soldered to the PCB’s ground
plane. The ball-grid array packages (BGA) offer centered VSS balls which should also be soldered to
PCB ground. This centered ground connection additionally serves as heat dissipation. E-pad and center
ground balls help to keep noise current return paths short, thus reducing emission radiation.

The system clock is the operating frequency of the TriCore CPU. Peripherals typically operate at lower
clock rates while the PLL itself generates a higher frequency. Operating a microcontroller at lower clock
rates reduces emission slightly. Because of the unchanged steepness of the clock edges, the general
emission behaviour stays nearly the same.

Some AudoMax devices support frequency modulation of the PLL clock. Note that the special operation
mode of the AudoMax-FMPLL is an enhanced triangular modulation which reduces the accumulated
jitter (or time interval error TIE) significantly, allowing reliable asynchronous serial data communication.
For details please refer to the Infineon microcontroller application note AP32185 [1]. Frequency
modulation of the system clock reduces emission significantly because the RF peak energy is then
distributed along side bands. On Infineon microcontrollers, the modulation amplitude is not limited by
TIE constraints.

All AudoMax devices provide pad driver scaling. The DC driver strength and slew rates can be selected
among two, four, or seven settings, depending on the respective I/O pin’s driver class. For details
please refer to the Infineon microcontroller application note AP32146 [2]. Driver scaling reduces
emission significantly along with slower switching times. Therefore, scaling is limited according to target
data rates and signal integrity.

An embedded linear voltage regulator is implemented on two AudoMax microcontrollers. It helps to
keep switching noise inside the microcontroller.
Product
Package
E-pad
System
clock
Clock
modulation
Scalable
pads
Embedded
voltage reg.
TC1724
QFP-144
soldered to GND
133 MHz
n/a
7 stages
VDD, VDDP
TC1728
QFP-176
soldered to GND
133 MHz
n/a
7 stages
VDD, VDDP
TC1782
QFP-176
soldered to GND
180 MHz
n/a
7 stages
no
TC1784
BGA-292
n/a
180 MHz
n/a
7 stages
no
TC1791
BGA-292
n/a
240 MHz
2.5 %
7 stages
no
TC1793
BGA-416
n/a
270 MHz
3.0 %
7 stages
no
TC1798
BGA-516
n/a
300 MHz
0.8 %
7 stages
no
Table 1
Main feature overview of the microcontrollers under test
For architectural details, please refer to the respective product specifications which can be downloaded from
www.infineon.com.
Test Report
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
2
Executive summary
2.1
Selected nets for emission comparison
The rating of microcontroller emission behaviour given in this document is based on much more comprehensive
measurements. Those are documented in the product-specific emission test reports which are available on
request. To be able to compare the emission characteristics of all AudoMax microcontrollers, the measurement
results provided in chapters 6 and 7 systematically show the emission spectra of:
 conducted emission of core supply domain (VDD 1.3 V),
 conducted emission of I/O supply domain (VDDP 3.3V),
 minimum conducted crosstalk emission found on any tested pin (“quiet pin”),
 maximum conducted crosstalk emission found on any tested pin (“noisy pin”),
 radiated emission of the whole microcontroller facing into a mini-TEM cell.
2.2
Test procedure compliance
All EMI test results presented in this report are obtained from hardware and software test setups compliant to
the “Generic IC EMC Test Specification” (“BISS paper”) [7], open copyright by Robert Bosch GmbH, Infineon
Technologies AG, Continental AG (former Siemens-VDO).
2.3
General emission result
Conducted and radiated emissions of the AudoMax 32-bit microcontrollers stay mostly below the BISS limits for
application-typical operation modes and configurations, which are:
 All function units are active.
 Reduced pad drivers are used.
 FMPLL (clock modulation) is activated.
 Series resistor is used in oscillator circuit between XTAL2 pin and crystal.
2.4
Conducted emission result
BISS limits for conducted emission may be violated for the following cases:

TC1724 on supply net VDD (4 harmonic 533 MHz: +4 dBµV). Thanks to the EVR, VDD is a local net
which is not considered to be critical.

TC1728 on supply net VDD (5 harmonic 666 MHz: +6 dBµV). Thanks to the EVR, VDD is a local net
which is not considered to be critical.

TC1782 on e.g. P2.0 (base frequency 180 MHz and 2 harmonic 360 MHz: +2 dBµV). External filters
should be considered for port pins close to the CPU which leave the application board.

TC1784 on supply net VDD (2 , 3 , 4 harmonic 360-720 MHz: +5..10 dBµV). The power supply
should be routed carefully; at least four PCB layers are recommended.

TC1791 on supply net VDD (system clock divided by 3 = 80 MHz: +3 dBµV).

TC1791 on port pins next to oscillator due to strong oscillator clock crosstalk (oscillator base frequency:
+9 dBµV). Use series resistor (e.g. 1 kΩ) between XTAL2 pin and crystal. Reduce oscillator gain to level
2 if signals are rated critical.

TC1793 worst-case I/O emission might exceed the BISS limit at very low frequencies. External filters
may be considered for port pins which leave the application board.

TC1798 on supply net VDD (system clock divided by 3 = 100 MHz: +3 dBµV).

TC1798 on port pins next to oscillator due to strong oscillator clock crosstalk (oscillator base frequency:
+6 dBµV). Use series resistor (e.g. 1 kΩ) between XTAL2 pin and crystal. Reduce oscillator gain to level
2 if signals are rated critical.
th
th
nd
nd
Test Report
rd
th
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
2.5
Radiated emission result
BISS limits for radiated emission may be violated for the following cases:

TC1724 7 system clock harmonic (933 MHz): +9 dBµV. Note: this emission peak is amplified by
unintended GSM interference. Mere microcontroller emission is less and should stay below the BISS
limit.

TC1728 7 system clock harmonic (933 MHz): +3 dBµV. Note: this emission peak is amplified by
unintended GSM interference. Mere microcontroller emission is less and should stay below the BISS
limit.

TC1782 between 500 and 650 MHz: +2 dBµV.

All other microcontrollers, i.e. those mounted in a ball-grid array package, show no radiated emission
violations of the limit curve.
th
th
2.6
PCB design recommendations
Special care on PCB layout is advisable to prevent supply and I/O noise from being coupled to any antenna
structures on the PCB. General PCB design guidelines are described in detail in the application note AP24026
[3]. Microcontroller-specific PCB design guidelines are described in detail in the related application notes [4]-[9].

Use common GND plane.

Design power islands below or around microcontroller in close vicinity.

Reach lowest possible power/ground impedance by avoiding plane/island cheesing by vias.

Solder the exposed die pad (e-pad) to the GND plane; see also chapter 8.1.

Place decoupling capacitors close to supply pins in a way that current return paths are kept low, and the
noise current is forced to flow through the capacitors.

Keep signal traces short.

Route “high-speed” signal traces as micro-strip or stripline (i.e. use ground shielding).

Avoid signal trace vias through power or ground planes.
2.7
Microcontroller configuration recommendations
Several microcontroller configurations provide significant emission reduction:

Use lowest permissable data rates.

Use weakest permissable pad driver settings; details are provided in chapter 8.2.

Activate the system clock modulation (FMPLL); details are provided in chapter 8.3.
For further recommendations please refer to Infineon’s application notes [1] and [2].
Test Report
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
3
Emission measurement methods
3.1
Conducted emission measurement
The setup used for electromagnetic emission measurement complies fully with the BISS test specification which
can be downloaded from the internet [10]. One test board was designed for every microcontroller under test with
similar layout. The test board is used for conducted and radiated emission measurements.
Conducted emission is measured using the standardized 150  network. This network is used for both port and
power supply emission measurements. Only crosstalk noise is measured; i.e. the port pins under test are never
actively switching. Frequency range is 150 kHz to 1 GHz.
Fig. 1 shows the schematic 150 Ω network connection to the microcontroller (IC under test) and the general
layout of each 150 Ω probing net.
Figure 1
150 Ω probing networks for conducted emission measurement
150 Ω networks are provided for conducted emission measurements according to the international standard IEC
61967 part 4 and the BISS test specification for a set of signals and power supply nets. The electromagnetic
emission comparison of various microcontrollers in this document is based on probing the main digital power
supply nets plus a “best case” and a “worst case” I/O pin. In fact, many more pins have been measured and
documented in the detailed product-specific EMC test reports which are available from Infineon on request.
Test Report
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
3.2
Radiated emission measurement
Radiated emission is measured using the standard mini TEM cell according to the international standard IEC
61967 part 2 and BISS emission test specification. The frequency range is from 150 kHz to 1 GHz.
Figure 2
3.3
Measurement setup for radiated emission
Measurement conditions and instruments
Measurement were performed under well-defined and unchanged conditions to provide a reliable repeatability:
Spectrum analyzer:
Rohde & Schwarz FSP7
Detector type:
Peak detector
Measurement time:
For all measurements, the emission measurement time (10ms) at one
frequency is longer than the test software loop duration.
Pre-Amplifier:
internal
Data generation software:
Rohde & Schwarz EMIPAK 9950
Environment:
Temperature 23°C ± 5°C
Supply:
Nominal voltage ± 5%
For all measurements the noise floor is at least 6dB below the limit.
Spectrum Analyzer
Frequency range
TEM
150 
RBW
150 kHz
to
30 MHz
30 MHz
to
200 MHz
200 MHz
to
1000 MHz
Table 2
10kHz
Sweep time*
ts 
NP  LT  FR
RBW
Spectrum analyzer setting
*) NP = number of points; LT = loop time; FR = frequency range
Test Report
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
4
Emission limit curves
For reference purpose, a respective limit curve is shown in all measured emission spectra. These curves are
taken from the BISS specification [10]. Figures 3 and 4 introduce these 3 limit curves:
 Conducted emission 150 Ω, limit for supply pin emission (i.e. VDDx domains),

Conducted emission 150 Ω, limit for port pin emission (i.e. I/O pins),

Radiated emission, limit for mini-TEM cell emission (not domain or pin specific).
Figure 3
Figure 4
Test Report
BISS limit curves in logarithmic scale
BISS limit curves in linear scale
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
As long as the measured emission stays below the respective limit, the measured supply or signal net is treated
as “clean”. If the measured emission violates the respective limit for one or more frequencies, some more care
must be taken for an EMC-friendly PCB layout. Infineon strongly recommends to use all microcontroller
hardware and software settings as explained in chapter 8. They will provide a significant reduction of
electromagnetic emission. Keep in mind that the usage of reduced pad drivers may be limited with respect to
the required system performance and signal integrity:

Reduce system clock frequency.

Disable unused clocks (e.g. CLKOUT, EXTCLK [automatically disabled after reset]).

Use frequency-modulated system clock (only available on TC1791, TC1793, TC1798) [1].

Reduce output pad driver strength (two, four or seven settings available for all port pins) [2].

Consider Infineon’s general and product-specific PCB design guidelines which propose optimized
power supply layout and decoupling concepts [3]-[9].
Test Report
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
5
Microcontroller operation during test
To get a realistic impression of the microcontroller’s emission potential, an “application-typical” operating mode
was configured during the tests. This means:

Program is executed from on-chip flash memory

CPU and all functional modules are active

System clock output is disabled

High-speed interfaces are active (e.g. FlexRay @ 10 Mbit/s, SPI @ 5 MBit/s, ASC / LIN / CAN @ 500
kBit/s)

Other I/Os run at lower data rates

EBU is active (available on TC1798 only)

All output pad driver strengths are selected matching their data rates, driving 22 pF load. Table 3 shows
the ratio of driver settings (all digital outputs without ADC channels) as it was used for the emission
tests:
TC1724
TC1728
TC1782
TC1784
TC1791
TC1793
TC1798
Driver strength
abs.
%
abs.
%
abs.
%
abs.
%
abs.
%
abs.
%
abs.
%
Weak & Pulldown
0
0
0
0
14
16
0
0
0
0
0
0
0
0
Medium
20
23
30
27
48
56
40
29
24
19
59
27
58
25
Strong-soft
67
77
77
69
24
28
95
68
96
75
153
69
163
71
LVDS
0
0
4
4
0
0
4
3
8
6
8
4
8
4
Total
87
100
111
100
86
100
139
100
128
100
220
100
229
100
Table 3
Pad driver scaling of the microcontrollers under test

Core supply voltage VDD = 1.30 V

I/O supply voltage VDDP = 3.30 V

The system clock is 133/180/240/270/300 MHz according to Table 1.

The crystal frequency is 20 MHz in all cases.

Devices from center fabrication lot were used, operating at nominal voltages and at room temperature.

Emissions are slightly, but negligibly increasing with higher supply voltages and lower ambient
temperature.

The fabrication lot influence is negligible.
Test Report
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6
Conducted emission measurement results
6.1
Microcontroller TC1724
6.1.1
TC1724: Probed nets
Fig. 5 shows the location of the four nets selected for emission measurement:
VDD 1.3V (embedded voltage regulator output)
VDDP 3.3V (embedded voltage regulator output)
P0.4 (min. noise level)
P2.0 (max. noise level)
Figure 5
6.1.2
TC1724 probed nets for electromagnetic emission
TC1724: Result summary
th
The TC1724 fulfills the BISS emission limits on all nets except VDD (4 harmonic: +4 dBµV).
Because of the EVR, VDD is an internal node without external connection to system voltage regulator, ECU
connector or cable. Therefore, the VDD net can be layouted locally, isolating its noise. Take care for short
current return paths through decoupling capacitors.
Test Report
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.1.3
TC1724: Conducted emission results
Fig. 6-9 show the emission measurement results at the four probed nets.
Figure 6
Figure 7
Test Report
TC1724; Application pattern; 133 MHz; VDD conducted
TC1724; Application pattern; 133 MHz; VDDP conducted
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
Figure 8
Figure 9
Test Report
TC1724; Application pattern; 133 MHz; best-case I/O conducted
TC1724; Application pattern; 133 MHz; worst-case I/O conducted
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.2
Microcontroller TC1728
6.2.1
TC1728: Probed nets
Fig. 10 shows the location of the four nets selected for emission measurement:
VDD 1.3V (embedded voltage regulator output)
VDDP 3.3V (embedded voltage regulator output)
P0.9 (min. noise level)
P2.0 (max. noise level)
Figure 10
6.2.2
TC1728 probed nets for electromagnetic emission
TC1728: Result summary
th
The TC1728 fulfills the BISS emission limits on all nets except VDD (5 harmonic: +6 dBµV).
Because of the EVR, VDD is an internal node without external connection to system voltage regulator, ECU
connector or cable. Therefore, the VDD net can be layouted locally, isolating its noise. Take care for short
current return paths through decoupling capacitors.
Test Report
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.2.3
TC1728: Conducted emission results
Fig. 11-14 show the emission measurement results at the four probed nets.
Figure 11
Figure 12
Test Report
TC1728; Application pattern; 133 MHz; VDD conducted
TC1728; Application pattern; 133 MHz; VDDP conducted
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TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
Figure 13
Figure 14
Test Report
TC1728; Application pattern; 133 MHz; best-case I/O conducted
TC1728; Application pattern; 133 MHz; worst-case I/O conducted
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TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.3
6.3.1
Microcontroller TC1782
TC1782: Probed nets
Fig. 15 shows the location of the four nets selected for emission measurement:
VDD 1.3V
VDDP 3.3V
P1.7 (min. noise level)
P2.0 (max. noise level)
Figure 15
6.3.2
TC1782 probed nets for electromagnetic emission
TC1782: Result summary
The TC1728 fulfills the BISS emission limits on all nets except P2.0 (crosstalk on base frequency and 2
harmonic: +2 dBµV).
nd
External filters should be considered for port pins close to the CPU which leave the application board.
Test Report
20
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.3.3
TC1782: Conducted emission results
Fig. 16-19 show the emission measurement results at the four probed nets.
Figure 16
Figure 17
Test Report
TC1782; Application pattern; 180 MHz; VDD conducted
TC1782; Application pattern; 180 MHz; VDDP conducted
21
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
Figure 18
Figure 19
Test Report
TC1782; Application pattern; 180 MHz; best-case I/O conducted
TC1782; Application pattern; 180 MHz; worst-case I/O conducted
22
V1.0, 2012-02
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.4
Microcontroller TC1784
6.4.1
TC1784: Probed nets
Fig. 20 shows the location of the four nets selected for emission measurement:
VDD 1.3V
VDDP 3.3V
P10.12 (min. noise level)
P1.5 (max. noise level)
Figure 20
6.4.2
TC1784 probed nets for electromagnetic emission
TC1784: Result summary
nd
rd
th
The TC1784 violates the BISS emission limits on VDD (2 , 3 , 4 harmonic: +5..10 dBµV).
The TC1784 reaches the BISS emission limits on port pins close to oscillator (e.g. P1.5) due to strong oscillator
clock crosstalk; critical frequency is the oscillator base frequency.
The oscillator should be operated with series resistor (e.g. 1 kΩ) between XTAL2 pin and crystal. Furthermore,
the oscillator gain may be reduced to level 2 (second-strongest value).
The power supply should be routed carefully; at least four PCB layers are recommended.
Test Report
23
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.4.3
TC1784: Conducted emission results
Fig. 21-24 show the emission measurement results at the four probed nets.
Figure 21
Figure 22
Test Report
TC1784; Application pattern; 180 MHz; VDD conducted
TC1784; Application pattern; 180 MHz; VDDP conducted
24
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
Figure 23
Figure 24
Test Report
TC1784; Application pattern; 180 MHz; best-case I/O conducted
TC1784; Application pattern; 180 MHz; worst-case I/O conducted
25
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.5
Microcontroller TC1791
6.5.1
TC1791: Probed nets
Fig. 25 shows the location of the four nets selected for emission measurement:
VDD 1.3V
VDDP 3.3V
P8.2 (min. noise level)
P9.14 (max. noise level)
Figure 25
6.5.2
TC1791 probed nets for electromagnetic emission
TC1791: Result summary
The TC1791 violates BISS emission limits on the power supply net VDD (system clock divided by 3: +3 dBµV).
The system frequency itself touches the BISS limit.
The TC1791 exceeds the BISS emission limits by 9 dBµV on port pins close to oscillator (e.g. P9.14) due to
strong oscillator clock crosstalk; critical frequency is the oscillator base frequency.
The oscillator should be operated with series resistor (e.g. 1 kΩ) between XTAL2 pin and crystal. Furthermore,
the oscillator gain may be reduced to level 2 (second-strongest value).
Test Report
26
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.5.3
TC1791: Conducted emission results
Fig. 26-29 show the emission measurement results at the four probed nets.
Figure 26
Figure 27
Test Report
TC1791; Application pattern; 240 MHz; VDD conducted
TC1791; Application pattern; 240 MHz; VDDP conducted
27
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
Figure 28
Figure 29
Test Report
TC1791; Application pattern; 240 MHz; best-case I/O conducted
TC1791; Application pattern; 240 MHz; worst-case I/O conducted
28
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.6
Microcontroller TC1793
6.6.1
TC1793: Probed nets
Fig. 30 shows the location of the four nets selected for emission measurement:
VDD 1.3V
VDDP 3.3V
P3.1 (min. noise level)
P1.3 (max. noise level)
Figure 30
6.6.2
TC1793 probed nets for electromagnetic emission
TC1793: Result summary
The TC1782 generally fulfills the BISS emission limits on all nets.
Worst-case I/O emission might exceed the BISS limit at very low frequencies. External filters may be considered
for port pins which leave the application board.
Test Report
29
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.6.3
TC1793: Conducted emission results
Fig. 31-34 show the emission measurement results at the four probed nets.
Figure 31
Figure 32
Test Report
TC1793; Application pattern; 270 MHz; VDD conducted
TC1793; Application pattern; 270 MHz; VDDP conducted
30
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
Figure 33
Figure 34
Test Report
TC1793; Application pattern; 270 MHz; best-case I/O conducted
TC1793; Application pattern; 270 MHz; worst-case I/O conducted
31
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.7
Microcontroller TC1798
6.7.1
TC1798: Probed nets
Fig. 35 shows the location of the four nets selected for emission measurement:
VDD 1.3V
VDDP 3.3V
P2.6 (min. noise level)
P9.14 (max. noise level)
Figure 35
6.7.2
TC1798 probed nets for electromagnetic emission
TC1798: Result summary
The TC1798 violates BISS emission limits on the power supply net VDD (system clock divided by 3: +3 dBµV).
The system frequency itself touches the BISS limit.
The TC1798 exceeds the BISS emission limits by 6 dBµV on port pins close to oscillator (e.g. P9.14) due to
strong oscillator clock crosstalk; critical frequency is the oscillator base frequency.
The oscillator should be operated with series resistor (e.g. 1 kΩ) between XTAL2 pin and crystal. Furthermore,
the oscillator gain may be reduced to level 2 (second-strongest value).
Test Report
32
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
6.7.3
TC1798: Conducted emission results
Fig. 36-39 show the emission measurement results at the four probed nets.
Figure 36
Figure 37
Test Report
TC1798; Application pattern; 300 MHz; VDD conducted
TC1798; Application pattern; 300 MHz; VDDP conducted
33
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AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
Figure 38
Figure 39
Test Report
TC1798; Application pattern; 300 MHz; best-case I/O conducted
TC1798; Application pattern; 300 MHz; worst-case I/O conducted
34
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
7
Radiated emission measurement results
7.1
Microcontroller TC1724
7.1.1
TC1724: Radiated emission result summary
th
The TC1724 fulfills the BISS emission limits except 7 system clock harmonic: +9 dBµV.
7.1.2
TC1724: Radiated emission result
Fig. 40 shows the radiated emission measurement result.
Figure 40
TC1724; Application pattern; 133 MHz; radiated
Note: The emission peak at 933 MHz is amplified by unintended GSM interference. Mere microcontroller
emission is less and should stay below the BISS limit.
Test Report
35
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
7.2
Microcontroller TC1728
7.2.1
TC1728: Radiated emission result summary
th
The TC1728 fulfills the BISS emission limits except 7 system clock harmonic: +3 dBµV.
7.2.2
TC1728: Radiated emission result
Fig. 41 shows the radiated emission measurement result.
Figure 41
TC1728; Application pattern; 133 MHz; radiated
Note: The emission peak at 933 MHz is amplified by unintended GSM interference. Mere microcontroller
emission is less and should stay below the BISS limit.
Test Report
36
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
7.3
Microcontroller TC1782
7.3.1
TC1782: Radiated emission result summary
The TC1782 fulfills the BISS emission limits except in the range between 500 and 650 MHz: +2 dBµV.
7.3.2
TC1782: Radiated emission result
Fig. 42 shows the radiated emission measurement result.
Figure 42
Test Report
TC1782; Application pattern; 180 MHz; radiated
37
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
7.4
Microcontroller TC1784
7.4.1
TC1784: Radiated emission result summary
The TC1784 fulfills the BISS emission limits.
7.4.2
TC1784: Radiated emission result
Fig. 43 shows the radiated emission measurement result.
Figure 43
Test Report
TC1784; Application pattern; 180 MHz; radiated
38
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
7.5
Microcontroller TC1791
7.5.1
TC1791: Radiated emission result summary
The TC1791 fulfills the BISS emission limits.
7.5.2
TC1791: Radiated emission result
Fig. 44 shows the radiated emission measurement result.
Figure 44
Test Report
TC1791; Application pattern; 240 MHz; radiated
39
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
7.6
Microcontroller TC1793
7.6.1
TC1793: Radiated emission result summary
The TC1793 fulfills the BISS emission limits.
7.6.2
TC1793: Radiated emission result
Fig. 45 shows the radiated emission measurement result.
Figure 45
Test Report
TC1793; Application pattern; 270 MHz; radiated
40
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
7.7
Microcontroller TC1798
7.7.1
TC1798: Radiated emission result summary
The TC1798 fulfills the BISS emission limits.
7.7.2
TC1798: Radiated emission result
Fig. 46 shows the radiated emission measurement result.
Figure 46
Test Report
TC1798; Application pattern; 300 MHz; radiated
41
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
8
Microcontroller configuration impact on emission
8.1
Emission influence from exposed die pad
Exposed die pads (e-pads) are used in leadframe packages to dissipate the static and dynamic IC power from
the die to the PCB without need for expensive heat sinks. Typical PCB layouts use “thermal vias” to transfer the
heat from the die through the PCB to the GND plane. TC1724, TC1728 and TC1782 offer an e-pad which is
electrically connected to the VSS (ground) net of the microcontroller. Since the standard assembly forms a
conducting connection between the PCB trace or plane and the e-pad, the e-pad must be soldered to the PCB
GND plane. The e-pads of all referenced microcontrollers in this document had been soldered to PCB-GND.
The e-pad provides a lower impedance connection and a shorter current return paths of all VSS supply pads on
the die, because all VSS pads are bonded onto the e-pad surface. By connecting the e-pad to the PCB GND
plane, a very low-ohmic connection between chip-GND and PCB-GND is established. For some electrical nets,
this conducting e-pad connection leads to slightly higher electromagnetic emission, due to easier noise
propagation from the die to the PCB. On the other hand, a disconnected e-pad leads to higher dynamic voltage
drop on the die during operation, thus reducing the margin for reliable operation. The electrical device
specification is nevertheless fulfilled.
The emission results in Fig. 47-50 are obtained from a TC1782 which was assembled in two ways: (1) e-pad
soldered to PCB-GND, and (2) mounted in a socket without conducting e-pad connection. The emission of a
soldered TC1782 without conducting e-pad connection will stay between any two measurement results provided
within one row of the result table.
TC1782 CE VDDC 180MHz APP SOCKET
60
60
55
55
50
50
45
45
40
40
35
35
dBµV
dBµV
TC1782 CE VDDC 180MHz APP
30
25
30
25
20
20
15
15
10
10
5
5
0
0
0
100
200
300
400
500
600
700
800
900
1000
0
100
200
300
400
Frequency/MHz
Figure 47
TC1782; soldered; e-Pad; Application;
VDD conducted; 180 MHz
Figure 48
600
700
800
900
1000
TC1782; Socket; no e-Pad; Application;
VDD conducted; 180 MHz
TC1782 CE P1.7 180MHz APP
TC1782 CE P1.7 180MHz APP SOCKET
60
60
55
55
50
50
45
45
40
40
35
35
dBµV
dBµV
500
Frequency/MHz
30
25
30
25
20
20
15
15
10
10
5
5
0
0
0
100
200
300
400
500
600
700
800
900
1000
0
100
Frequency/MHz
Figure 49
Test Report
TC1782; soldered; e-Pad; Application;
P1.7 conducted; 180 MHz
200
300
400
500
600
700
800
900
1000
Frequency/MHz
Figure 50
42
TC1782; Socket; no e-Pad; Application;
P1.7 conducted; 180 MHz
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
8.2
Emission influence from scaled pad drivers
For emission measurements, so called “application-typical” microcontroller configurations as described in
chapter 5 are used. All function units are active, but the port pin drivers do not use their their strongest default
settings after reset. Instead, weaker driver settings are configured. The actual driver scaling per pin depends on
the data rate this pin must provide with good signal integrity. According Table 3 in chapter 5, none of the pads
are using driver strengths stronger than “strong-soft”. The used “weak”, “medium” and “strong-soft” settings
keep the pad switching emission low and should be preferred in any application. Fast data rates recommend for
strong driver settings, but even here, the microcontrollers provide several sub-settings, depending on the
microcontroller family. Fig. 47 provides a generic overview of emission reduction potential when weaker pad
driver settings are used. The strongest driver (“strong-sharp”, default after reset) serves as the 0dB reference
line. Any pad driver scaling other than “strong-sharp” leads to significant emission reduction up to 30dB
(“weak”). Please note that driver settings “strong-sharp-minus”, “strong-medium-minus” and “strong-slow” are
only available in the TC1782. In addition, the emission reduction numbers in dB should be treated as rough
reference. The real numbers may differ. For details, please refer to the Infineon Application Notes [1] [2].
Figure 51
Emission reduction by pad driver settings for VDDP = 3.3 V and Cload = 22 pF at 25°C
Infineon strongly recommends to use the pad driver scaling feature in order to reduce electromagnetic emission.
The lists of pin-wise driver settings for the microcontrollers under test are given in the microcontroller-specific
full electromagnetic emission reports which are available upon request.
If many port pins are operated using strong pad driver settings, the electromagnetic emission behavior may be
worse than shown in the measurement diagrams within this document.
Test Report
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V1.0, 2012-02
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
The following conducted emission results have been obtained from TC1782. Emission reduction depends on the
pin and the signal integrity constraints. Nevertheless, the following Fig. 40 and 41 indicate up to 10 dB emission
reduction on VDDP and up to 20 dB emission reduction on P0.9.
Test Report
Figure 52
TC1793; Application pattern; 270 MHz; best-case I/O conducted
Figure 53
TC1793; Application pattern; 270 MHz; best-case I/O conducted
44
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
8.3
Emission influence from clock frequency modulation
Unmodulated clocks keep their energy in the narrow-band peaks along the clock harmonic frequencies. Clock
frequency modulation leads to a distribution of the same energy into lower and upper side-bands of those
harmonics. Thus the peak energy of the clock harmonics decreases according to the modulation amplitude.
Unfortunately, standard triangular frequency modulation causes significant time shifts of the clock edges
towards an unmodulated clock with same frequency. For that reason, this clocking technology cannot be applied
to asynchronous data interfaces. Infineon developed an advanced clock modulation technique which offers
similar emission reduction together with a strict limitation of clock edge shift, i.e. the resulting time interval error
TIE stays very low. Details can be found in [1]. Therefore, the FMPLL feature of the AudoMax microcontrollers
TC1791, TC1793 and TC1798 allows proper operation of asynchronous data communication like CAN while
benefitting from up to 20 dB emission reduction, see Fig. 54-59.
Figure 54
Figure 56
Figure 58
Test Report
TC1793; VDD conducted; FMPLL off
Figure 55
TC1793; VDDP conducted; FMPLL off
Figure 57
TC1793; P3.1 conducted; FMPLL off
Figure 59
45
TC1793; VDD conducted; FMPLL on
TC1793; VDDP conducted; FMPLL on
TC1793; P3.1 conducted; FMPLL on
V1.0, 2012-02
AP32193
Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
9
References
These documents can be downloaded from the Infineon microcontroller internet pages www.infineon.com
[1] Application Note AP32185 “Frequency-modulated PLL“; Parameters, effects, programming
[2] Application Note AP32146 “Scalable pads in 90nm microcontrollers“; Timing and emission
[3] Application Note AP24026 “General EMC guidelines for PCB design”
[4] Application Note AP32181 “EMC guidelines for PCB design – TC172x”
[5] Application Note AP32145 “EMC guidelines for PCB design – TC1782”
[6] Application Note AP32161 “EMC guidelines for PCB design – TC1784”
[7] Application Note AP32162 “EMC guidelines for PCB design – TC1791”
[8] Application Note AP32163 “EMC guidelines for PCB design – TC1793”
[9] Application Note AP32164 “EMC guidelines for PCB design – TC1798”
The BISS test specification can be downloaded from http://www.zvei.org/IC_EMC_Test_Specification
[10] Generic IC EMC Test Specification (“BISS paper”),
open copyright by Robert Bosch GmbH, Infineon Technologies AG, Continental AG;
Detailed electromagnetic emission and immunity test reports for all AudoMax microcontrollers are available on
request.
Test Report
46
V1.0, 2012-02
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Electromagnetic Emission Summary
TriCore™ AudoMax Derivatives TC1724, TC1728, TC1782, TC1784, TC1791, TC1793, TC1798
10
Abbreviations
BGA
Ball-grid array IC package
BISS
Bosch/Continental/Infineon IC EMC Test Specification
CPU
Central processing unit
EBU
External bus unit (e.g. external flash or SRAM communication)
EMC
Electromagnetic compatibility
EME
Electromagnetic emission
e-Pad
Exposed die pad
EVR
Embedded voltage regulator
FMPLL
Frequency-modulated phase-locked loop
LDO
Linear voltage regulator output
PCB
Printed circuit board
PLL
Phase-locked loop (e.g. system clock generation)
QFP
Quad flat-pack lead-frame IC package
TIE
Time interval error
Test Report
47
V1.0, 2012-02
w w w . i n f i n e o n . c o m
Published by Infineon Technologies AG
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