Application Note

VISHAY SEMICONDUCTORS
www.vishay.com
Infrared Remote Control Receivers
Application Note
Using Vishay Infrared Receivers in a Wi-Fi Environment
By Michael Laemmlen and John Fisher
In recent years, Wi-Fi connectivity has penetrated most consumer electronic devices used for media reproduction. New TVs,
satellite receiver and cable boxes, and streaming devices are more often than not built with Wi-Fi capabilities at multiple
frequencies: 2.4 GHz and 5 GHz. Most of these appliances continue to support an infrared (IR)-based remote control link, often
even when the device also supports a newer RF-based remote control.
IR remote control receivers are built with highly sensitive wideband input stages and are able to detect signals near the noise
level of their circuitry. In noisy environments, such as with both low- and high-frequency electromagnetic interference (EMI), the
receiver may be noise-triggered, typically manifesting itself in the form of spurious pulses at its output. Most Vishay IR receiver
packages are designed with metal shields to effectively guard the receiver against low-frequency EMI. However, these metal
shields have not proven entirely satisfactory against high-frequency EMI in the GHz range used for Wi-Fi.
Empirical testing has shown that a number of factors play a role in the robustness of a package to RF noise. The internal shield
design, differences in receiver IC design, the automatic gain control (AGC) setting programmed into the chip: all of these factors
affect the receiver’s sensitivity to RF. Metal holders may improve or worsen RF robustness, depending on their design. Adding
RF capacitors between the supply and ground, and between the output and ground, is another proven - albeit expensive method to improve the RF rejection. Such capacitors may serve as an emergency measure once an RF problem is detected
when a design is already in an advanced stage. The primary design goal, however, is to not require them. The most significant
factors governing whether an IR receiver exhibits RF triggered noise are the power level of the RF signal and the distance the
receiver package is mounted away from the RF antenna. Lowering the power and increasing the distance both lower the chance
of disturbance.
In this application note, the effects of all these factors are quantified as an aid to selecting the most appropriate Vishay IR
receivers in Wi-Fi environments. Testing methodology and test data supporting the recommendations are presented.
TEST METHODOLOGY
Test Equipment
The RF signal source used for all the tests was an off-the-shelf WLAN router in combination with a USB network interface
controller (NIC) fulfilling the IEEE 802.11ac specification for 5 GHz and IEEE 802.11n for 2.4 GHz. The USB NIC had a maximum
output power of 200 mW and contained an integrated RF antenna. It was observed in all tests that the device under test (DUT)
was more sensitive to noise at 5 GHz at a power level of 200 mW than to the less powerful noise at 2.4 GHz at 100 mW. A
repeatable RF noise environment was created by placing the test board containing the DUT at a measured distance from the
NIC antenna. A streaming routine was then initiated that sent a large file from the NIC to the router.
Test PCB Layout and Spatial Location with Respect to the RF Antenna
Fig. 1
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APPLICATION NOTE
Bare TSOP38138 mounted on a test PCB
Application Note
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Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
Front of PCB
Back of PCB
(with 1 kΩ pull-up for fast edges, no capacitor)
Fig. 2
Note
• For tests with metal holders, the holders were always connected to GND potential.
The length of each supply and output line was 0.5 m. To avoid coupling effects, no crossovers or turns in leads were allowed.
Fig. 3
The DUT was positioned a known distance from the RF antenna prior to transmission of the RF test pattern.
Revision: 06-Jun-16
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APPLICATION NOTE
Fig. 4
Application Note
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Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
Test Conditions
All measurements were performed in dark ambient. IR receivers contain an AGC that reacts to the ambient light levels. In dark
ambients, the receiver’s gain will settle to its maximum sensitivity level, thus providing a repeatable known state. This maximum
gain level is also the operating condition most susceptible to seeing a disturbance from noise.
Measurement 1: the DUT was mounted at a set distance from the RF antenna. The RF data transmission was then initiated
from the NIC to the router, and any spurious pulses at the output of the IR receiver were counted within 60-second intervals.
This procedure was repeated several times, and an average value was calculated. The test board was then moved to a new
position from the antenna and the test was repeated.
Measurement 2: the distance between the DUT and the RF antenna was adjusted during data transmission to find the
“threshold” distance. The threshold distance is defined as the minimum distance between the DUT and the antenna for which
there is no significant disturbance to the IR receiver. At distances closer than the threshold, spurious pulses became a problem.
At distances equal to and further than the threshold, no noise issues could be observed.
Note
• In all tables, an orange tinted background denotes devices containing the “Aether” receiver IC, the devices with a green tinted background
contain the “Methone” receiver IC. The Methone IC architecture is generally more robust against RF noise.
SUMMARY OF TEST RESULTS: SURFACE-MOUNT PACKAGES
PACKAGE
Panhead
FREQUENCY
(GHz)
2.4
5
Heimdall
2.4
5
2.4
5
Revision: 06-Jun-16
5 cm
3 cm
1 cm
0 cm
THRESHOLD
(cm)
TSOP36338
0
0
0
700
1
TSOP36438
0
0
0
100
1
TSOP6338
0
0
0
0
0
TSOP6438
0
0
0
0
0
TSOP36338
> 20 000
> 20 000
> 20 000
> 20 000
19
TSOP36438
2300
2700
2800
2700
19
TSOP6338
800
15 000
15 000
17 000
11
TSOP6438
30
250
3000
7000
6
TSOP75338
0
0
0
250
1
TSOP75438
0
0
0
170
1
TSOP77338
0
0
0
0
0
TSOP77438
0
0
0
0
0
TSOP75338
9000
9300
15 000
> 20 000
11
TSOP75438
700
1100
1900
2700
11
TSOP77338
0
0
0
0
0
TSOP77438
0
0
0
0
0
TSOP37338
0
0
20
7000
2
TSOP37438
0
0
0
400
1
TSOP57338
0
0
0
0
0
TSOP57438
0
0
0
0
0
TSOP37338
1300
8000
10 000
> 20 000
10
TSOP37438
900
1700
2300
5000
10
TSOP57338
0
0
0
8000
1
TSOP57438
0
0
0
4000
1
3
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APPLICATION NOTE
Belobog
DUT
Application Note
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Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
SUMMARY OF TEST RESULTS: LEADED PACKAGES WITHOUT HOLDER
PACKAGE
Minicast
FREQUENCY
(GHz)
2.4
5
Mold
2.4
5
Minimold
2.4
5
DUT
5 cm
3 cm
1 cm
0 cm
THRESHOLD
(cm)
TSOP38338
0
0
2000
5000
2
TSOP38438
0
0
300
500
2
TSOP58338
0
0
0
0
0
TSOP58438
0
0
0
0
0
TSOP38338
900
4700
12 500
> 20 000
10
TSOP38438
150
600
800
1800
6
TSOP58338
0
0
0
300
1
TSOP58438
0
0
0
300
1
TSOP34338
0
30
12000
15 000
4
TSOP34438
0
20
1200
1300
4
TSOP4338
0
0
0
0
0
TSOP4438
0
0
0
0
0
TSOP34338
< 20 000
< 20 000
< 20 000
< 20 000
18
TSOP34438
2500
3000
3500
4200
16
TSOP4338
0
20
7000
15 500
4
TSOP4438
0
10
1900
3000
4
TSOP33338
0
0
60
3000
2
TSOP33438
0
0
0
80
1
TSOP53338
0
0
0
0
0
TSOP53438
0
0
0
0
0
TSOP33338
2400
16 000
20 000
> 20 000
17
TSOP33438
500
1300
1700
2700
15
TSOP53338
0
0
0
400
1
TSOP53438
0
0
0
400
1
Note
• The results shown in the table for leaded packages without holders are also valid when using these parts in plastic holders. Vishay makes a
wide variety of holders in both plastic and metal. The plastic material has no effect on the RF characteristics. If the base part has acceptable
RF characteristics for an application, it is safe to use the same part in combination with a plastic holder. Metal holders usually will change
the RF characteristics, sometimes for the worse. But with careful design, it can be shown that metal holders can also be constructed that
achieve an even higher robustness than the base part. This is the topic of the next section.
TEST RESULTS OF LEADED PARTS WITH A SELECTION OF METAL HOLDERS
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APPLICATION NOTE
A metal holder is one of the few practical means of changing the RF characteristics of a particular IR receiver once it is already
in production. Given that a holder is often required in many chassis designs in order to accurately position the receiver behind
an IR window, any gains that can be achieved in RF shielding via the holder are then a bonus. A study was undertaken to
compare the RF suppression of the base part with several standard metal holders, these same metal holders modified by
encasing them as fully as possible with copper sheet, and the same metal holders with an additional ground connection on the
front face but without a copper sheet. The testing was only carried out on AGC1 and AGC3 type parts. AGC1 and AGC3 typically
perform worse than AGC4, for example, with respect to RF noise suppression. The rationale for testing with these less robust,
odd-numbered AGCs was to achieve a more easily observable effect from our tests, as a holder design cannot be shown to
improve performance if the base part already fully suppresses the noise. The reader should keep in mind that generally, the
results will be better than those presented here for AGC4 type parts. Vishay recommends using AGC4 whenever the burst
lengths in your data are all longer than 10 carrier cycles.
Application Note
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Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
Minicast Package with Metal Holders CA1, CB1, and CC1
TSOP38138 and TSOP58138 bare parts and with a CA1 holder in three versions:
TSOP38138
TSOP58138
Standard CA1
CA1 holder, Cu shield
CA1 face GND
SUMMARY OF TEST RESULTS
PACKAGE
FREQUENCY
(GHz)
2.4
Minicast CA1
5 cm
3 cm
1 cm
0 cm
THRESHOLD
(cm)
TSOP38138 base part
0
0
10
12 000
2
TSOP38138 CA1 standard
0
0
3
9300
1
TSOP38138 CA1 Cu shield
0
0
12
9000
2
TSOP38138 CA1 face GND
0
0
0
40
1
TSOP58138 base part
0
0
0
0
0
TSOP58138 CA1 standard
0
0
0
0
0
DUT
TSOP58138 CA1 face GND
0
0
0
0
0
140
1800
12 500
> 20 000
8
TSOP38138 CA1 standard
0
130
3900
14 000
5
TSOP38138 CA1 Cu shield
0
285
1700
18 200
5
TSOP38138 CA1 face GND
0
0
700
14 000
2
TSOP58138 base part
0
0
60
2200
2
TSOP58138 CA1 standard
0
0
0
0
0
TSOP58138 CA1 face GND
0
0
0
0
0
TSOP38138 base part
5
5
Document Number: 82752
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ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
APPLICATION NOTE
Revision: 06-Jun-16
Application Note
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Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
TSOP38138 and TSOP58138 bare parts and with a CB1 holder in two versions:
TSOP38138
TSOP58138
Standard CB1
CB1 face GND
SUMMARY OF TEST RESULTS
PACKAGE
FREQUENCY
(GHz)
Minicast CB1
2.4
5 cm
3 cm
1 cm
0 cm
THRESHOLD
(cm)
TSOP38138 base part
5
50
5500
> 20 000
5
TSOP38138 CB1 standard
0
1
600
> 20 000
2
TSOP38138 CB1 face GND
DUT
700
4500
> 20 000
> 20 000
9
TSOP58138 base part
0
0
0
0
0
TSOP58138 CB1 standard
0
0
0
0
0
TSOP58138 CB1 face GND
0
0
0
0
0
> 20 000
> 20 000
> 20 000
> 20 000
25
TSOP38138 CB1 standard
1
250
250
> 20 000
4
TSOP38138 CB1 face GND
0
0
1
> 20 000
1
TSOP58138 base part
0
0
100
> 20 000
2
TSOP58138 CB1 standard
0
0
0
4
0
TSOP58138 CB1 face GND
0
0
0
30
1
TSOP38138 base part
5
6
Document Number: 82752
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ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
APPLICATION NOTE
Revision: 06-Jun-16
Application Note
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Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
TSOP38138 and TSOP58138 bare parts and with a CC1 holder in two versions:
TSOP38138
TSOP58138
Standard CC1
CC1 face GND
SUMMARY OF TEST RESULTS
PACKAGE
FREQUENCY
(GHz)
Minicast CC1
2.4
5 cm
3 cm
1 cm
0 cm
THRESHOLD
(cm)
TSOP38138 base part
0
3
60
2000
2
TSOP38138 CC1 standard
0
0
10 000
> 20 000
3
TSOP38138 CC1 face GND
0
20
4000
> 20 000
4
TSOP58138 base part
0
0
0
0
0
TSOP58138 CC1 standard
0
0
0
0
0
DUT
TSOP58138 CC1 face GND
0
0
0
0
0
14 500
> 20 000
> 20 000
> 20 000
12
TSOP38138 CC1 standard
700
10 000
> 20 000
> 20 000
8
TSOP38138 CC1 face GND
500
13 000
> 20 000
> 20 000
8
TSOP58138 base part
0
0
20
> 20 000
2
TSOP58138 CC1 standard
0
0
0
500
1
TSOP58138 CC1 face GND
0
0
0
6000
1
TSOP38138 base part
5
7
Document Number: 82752
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ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
APPLICATION NOTE
Revision: 06-Jun-16
Application Note
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Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
Mold Package with Metal Holders JH1, CD1, and CZ1
TSOP34338 and TSOP4338 bare parts and with a JH1 holder in two versions:
TSOP34338
TSOP4338
Standard JH1
JH1 face GND
SUMMARY OF TEST RESULTS
PACKAGE
FREQUENCY
(GHz)
Mold JH1
2.4
5 cm
3 cm
1 cm
0 cm
THRESHOLD
(cm)
TSOP34338 base part
0
0
600
10 000
2
TSOP34338 JH1 standard
0
0
3000
16 500
2
TSOP34338 JH1 face GND
0
0
1500
15 000
2
TSOP4338 base part
0
0
0
0
0
TSOP4338 JH1 standard
0
0
0
0
0
TSOP4338 JH1 face GND
0
0
0
0
0
DUT
TSOP34338 base part
5
< 20 000
< 20 000
< 20 000
13
0
0
2
2200
1
TSOP34338 JH1 face GND
0
4
2500
< 20 000
2
TSOP4338 base part
20
4000
16 200
17 600
6
TSOP4338 JH1 standard
0
0
0
1
0
TSOP4338 JH1 face GND
0
0
0
5
0
8
Document Number: 82752
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APPLICATION NOTE
Revision: 06-Jun-16
< 20 000
TSOP34338 JH1 standard
Application Note
www.vishay.com
Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
TSOP34338 and TSOP4338 bare parts and with a CD1 holder in three versions:
TSOP34338
TSOP4338
Standard CD1
CD1 Cu strip
CD1 face GND
SUMMARY OF TEST RESULTS
PACKAGE
FREQUENCY
(GHz)
Mold CD1
2.4
5 cm
3 cm
1 cm
0 cm
THRESHOLD
(cm)
TSOP34338 base part
0
25
6100
12 000
4
TSOP34338 CD1 standard
0
2
9000
17 400
3
TSOP34338 CD1 Cu shield
0
0
6500
13 000
3
TSOP34338 CD1 face GND
0
0
5
70
1
TSOP4338 base part
0
0
0
0
0
TSOP4338 CD1 standard
0
0
0
0
0
TSOP4338 CD1 face GND
0
0
0
0
0
DUT
TSOP34338 base part
5
13 500
> 20 000
> 20 000
17
> 20 000
> 20 000
> 20 000
> 20 000
28
TSOP34338 CD1 Cu shield
22
3600
> 20 000
> 20 000
7
TSOP34338 CD1 face GND
17 500
> 20 000
> 20 000
> 20 000
20
TSOP4338 base part
0
0
13 000
> 20 000
3
TSOP4338 CD1 standard
0
400
17 000
> 20 000
5
TSOP4338 CD1 face GND
0
0
200
8000
2
9
Document Number: 82752
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APPLICATION NOTE
Revision: 06-Jun-16
9000
TSOP34338 CD1 standard
Application Note
www.vishay.com
Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
TSOP34338 and TSOP4338 bare parts and with a CZ1 holder in two versions:
TSOP34338
TSOP4338
Standard CZ1
CZ1 face GND
SUMMARY OF TEST RESULTS
PACKAGE
FREQUENCY
(GHz)
Mold CZ1
2.4
5 cm
3 cm
1 cm
0 cm
THRESHOLD
(cm)
TSOP34338 base part
0
10
2300
11 000
4
TSOP34338 CZ1 standard
0
1
1500
11 000
3
TSOP34338 CZ1 face GND
DUT
300
2500
15 000
> 20 000
8
TSOP4338 base part
0
0
0
0
0
TSOP4338 CZ1 standard
0
0
0
0
0
TSOP4338 CZ1 face GND
5
0
0
0
0
5000
18 000
> 20 000
> 20 000
13
TSOP34338 CZ1 standard
4500
> 20 000
> 20 000
> 20 000
10
TSOP34338 CZ1 face GND
0
15
100
16 500
4
TSOP4338 base part
0
0
8000
> 20 000
2
TSOP4338 CZ1 standard
0
0
500
20 000
2
TSOP4338 CZ1 face GND
0
0
0
500
1
10
Document Number: 82752
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ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
APPLICATION NOTE
Revision: 06-Jun-16
0
TSOP34338 base part
Application Note
www.vishay.com
Vishay Semiconductors
Using Vishay Infrared Receivers in a Wi-Fi Environment
Minimold Package with Metal Holders CA1
TSOP33338 and TSOP53338 bare parts and with a CA1 holder in two versions:
TSOP33338
TSOP53338
Standard CA1
CA1 face GND
SUMMARY OF TEST RESULTS
PACKAGE
FREQUENCY
(GHz)
Minimold CA1
2.4
5 cm
3 cm
1 cm
0 cm
THRESHOLD
(cm)
TSOP33338 base part
0
0
30
2000
2
TSOP33338 CA1 standard
0
0
100
5000
2
TSOP33338 CA1 face GND
0
0
0
3
0
TSOP53338 base part
0
0
0
0
0
TSOP53338 CA1 standard
0
0
0
0
0
TSOP53338 CA1 face GND
0
0
0
0
0
DUT
TSOP33338 base part
22907
19 000
> 20 000
> 20 000
13
0
400
1800
4000
5
TSOP33338 CA1 face GND
1
50
4500
> 20 000
5
TSOP53338 base part
0
0
0
0
0
TSOP53338 CA1 standard
0
0
0
0
0
TSOP53338 CA1 face GND
0
0
0
0
0
11
Document Number: 82752
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
APPLICATION NOTE
Revision: 06-Jun-16
5
5000
TSOP33338 CA1 standard
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