an1406

ISL54209EVAL1Z Evaluation Board
User’s Manual
®
Application Note
Description
July 14, 2008
AN1406.0
Picture of Evaluation Board (Top View)
The ISL54209EVAL1Z evaluation board is designed to
provide a quick and easy method for evaluating the
ISL54209 USB/Audio Switch IC.
The ISL54209 device is an unique IC. To use this evaluation
board properly requires a thorough knowledge of the
operation of the IC. Refer to the data sheet for an
understanding of the functions and features of the device.
Studying the device’s truth-table along with its pinout
diagram on page 2 of the ISL54209 data sheet is the best
way to get a quick understanding of how the part works.
A picture of the main evaluation board is shown in Figure 1.
The ISL54209 TDFN IC is soldered onto the evaluation
board. It is located in the center of the board and is
designated as U1.
The ISL54209 IC has two modes of operation called Audio
mode and USB mode. The evaluation board contains
standard Audio and USB connectors to allow the user to
easily interface with the IC to evaluate its functions, features,
and performance in the two modes of operation.
For example, when the board is properly powered, a
headphone can be plugged into the headphone jack (J7) and
a stereo source, such as a MP3 player, can be connected at
the RCA connectors J3 (AUDIO LEFT) and J4 (AUDIO
RIGHT) to play music through the audio switches of the IC
(Figure 2). You can then turn-off the audio source, remove
the headphones, configure the logic for USB operation and
then attach a USB cable from a computer to the USB
connector J1 (USB TO HOST). This will establish a
connection from the computer through the USB switches of
the IC to the USB device connected at the USB connector J2
(USB TO DEVICE), to send and receive data.
This application note will guide the user through the process
of configuring and using the evaluation board to evaluate the
ISL54209 device in both the Audio mode and the USB
mode.
Features
• Standard USB Connectors
• RCA Audio Input Jacks and Headphone Speaker Jack
• Convenient Test Points and Connections for Test
Equipment
1
FIGURE 1. ISL54209EVAL1Z EVALUATION BOARD
Board Architecture/Layout
Basic Layout of Evaluation Board
The basic layout of the main board is as follows: Refer to
Figure 1.
1. Power and Ground connections are at the top of the
board (J10 and J11).
2. Logic control connections are at the top of the board (J12
and J13).
3. Audio Source Inputs are at the lower right side of the
board (J3 - J6). Audio outputs are at the lower left side of
the board (J7, J8, J9). Connector J7 is a standard
headphone jack for connecting a 32Ω headphone.
4. USB connection to an upstream host controller
(Computer) is made at connector J1, located on left
under-side of the board. USB connection to a
downstream USB device is made at connector J2,
located on right underside of the board.
5. Located in the center of the board is the ISL54209 IC
(U1). The evaluation board has a pin 1 dot, to show how
the IC should be oriented onto the evaluation board. The
IC pin 1 indicator dot needs to be aligned with the
evaluation board pin 1 dot indicator.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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Application Note 1406
Power Supply
The DC power supply connected at banana jacks J10 (VDD)
and J11 (GND) provides power to the part. The IC requires a
2.7V to 5.5V DC power supply for proper operation. The
power supply should be capable of delivering 100µA of
current.
Logic Control
The state of the ISL54209 device is determined by the
voltage at the IN pin and the CTRL pin.
Access to the CTRL pin is through the banana jack J12
(CTRL).
Access to the IN pin is through banana jack J13 (IN) when
jumper JP3 is in position 2 to 3 and through the USB J1
(USB TO HOST) connector VBUS line when the jumper JP3
is in position 2 to 1.
The following control pins are 1.8V logic compatible which
allows for control via a standard µcontroller.
Logic “0” (LOW) when ≤ 0.5V or floating
Logic “1” (HIGH) when ≥ 1.4V
Note: The evaluation board has the option of putting a 4MΩ
pull-down resistor from the IN pin to ground by putting a
jumper at JP4. However it is not required for the ISL54209
part because the IN and CTRL pins have internal 4MΩ
pull-down resistor. These resistors pull the logic pins to
ground when J13, J1, or J12 are floated.
If IN is driven LOW and CTRL is HIGH the part will be in the
Audio mode. The audio switches will be ON and the USB
switches will be OFF.
If IN is driven HIGH and CTRL = X (don’t care) the part will
be in the USB mode. The USB switches will be ON and the
audio switches will be OFF.
If IN is LOW and CTRL = LOW the part will be in the Low
Power mode. In Low Power mode all switches are OPEN
and the part will draw around 1nA of current.
SETTING UP THE EVALUATION BOARD TO USE THE
COMPUTER VBUS VOLTAGE TO DRIVE THE “IN’ PIN
Rather than using a logic controller to control the IN logic pin
through the J13 (IN) banana jack, you can directly drive the
IN pin using the VBUS voltage from the computer through the
USB J1 (USB TO HOST) connector.
To control the part through the J1 connector make the
following connections:
1. Install jumper JP3 at location 2 to 1. This connects the
Vbus line of the J1 USB connector to the IN pin of the
part. Note: With the jumper in this position the J13
banana jack is no longer connected to the IN pin of the
part.
2. A 500kΩ resistor should be put in series with the IN pin if
the VBUS voltage is greater than the VDD voltage. This
resistor is not on the evaluation board. There is an
2
internal diode in the IC from the IN pin to VDD that will get
forward biased and draw current as the voltage at the IN
pin exceeds the VDD voltage. With VBUS = 5.25V and
VDD = 3.3V, this resistor will limit the current to around
2.76µA and the voltage at the IN pin will be around 3.6V
which is well above the VinH minimum level of 1.4V
required for proper operation.
When the computer is not connected at J1, the internal
pull-down will pull the IN pin low putting the ISL54209 in the
Audio mode or Low Power mode depending on the condition
of the CTRL pin.
When a USB cable from the computer is connected at J1,
the voltage at the IN pin will be driven high and the part will
automatically go into the USB mode.
Audio Inputs
The evaluation board has two audio inputs labeled AUDIO
LEFT (J3 or J5) and AUDIO RIGHT (J4 or J6). Each of these
inputs have a BNC connector wired in parallel with a RCA
jack connector. You can connect an audio source/generator
at either the BNC connector or the RCA connector.
In a typical application, the left and right outputs of a stereo
source, such as an MP3 player, would be connected to the
RCA jacks J3 and J4, respectfully.
Over a signal range of ±1V (0.707Vrms) these switches have
an extremely low rON resistance variation. They can pass
ground referenced audio signals with very low distortion
(<0.05% THD+N) when delivering 15.6mW into a 32Ω
headphone speaker load. A 3Vp-p signal is acceptable but
performance will degrade.
The audio input channels are AC coupled with 100µF
capacitors. These capacitors remove any DC voltage from
the audio signals and reference them to ground of the
device. If the audio source being connected to the evaluation
board already has internal AC coupling capacitors at the
output of its drivers then the capacitors on the evaluation
board should be shorted out (replaced with 0Ω resistors).
This will prevent further attenuation of the low frequency
content of the audio signal due to the increase of the
high-pass corner frequency resulting from the evaluation
board capacitor in series with the audio source capacitor.
Audio Outputs
The evaluation board has a standard headphone jack
labeled HEADPHONE JACK (J7). A 32Ω stereo headphone
should be plugged into this jack.
The BNC connector J8 (COM-) is in parallel with the audio
left line of the headphone jack and the D- line of the J1 (USB
To HOST) connector. The BNC connector J9 (COM+) is in
parallel with the audio right line of the headphone jack and
the D+ line of the J1 (USB To DEVICE) connector. These
BNC connectors can be used to connect resistive loads
and/or test equipment to evaluate the performance of the IC.
July 14, 2008
Application Note 1406
USB Connections
A “B” type USB receptacle labeled “USB TO HOST” (J1) is
located on the left under-side of the board. This receptacle
should be connected using a standard USB cable to the
upstream USB host controller which is usually a PC
computer or hub. When this connection is made and the IN
logic control is driven HIGH, the ISL54209 device will go into
USB mode. The USB switches will be turned ON.
headphone speaker jack, J7. This will prevent the audio load
from interfering with USB signal transmission. The main
purpose of the ISL54209 device is to allow the use of a
common USB and Audio Headphone Connector in Personal
Media Players and other portable battery powered
equipment. Either a headphone will be in the common
connector to play music or a USB cable from a computer will
be in the common connector to transmit digital data
(ie: MP3), into the memory of the Media Player.
An “A” type USB receptacle labeled USB TO DEVICE (J2) is
located on the right underside of the board. The USB device
can be plugged directly into this receptacle or through a
standard USB cable.
The BNC connector J8 (COM-) is in parallel with the D- line
of the J1 USB connector. The BNC connector J9 (COM+) is
in parallel with the D+ line of the J1 USB connector.
In USB mode, the USB host controller and USB device will
be connected through the internal USB switches of the IC.
The USB switches are bi-directional which allow the host
(computer) and downstream USB device to both send and
receive data.
Note: Before connecting the USB host controller at
connector J1, the headphones must be removed from the
The BNC connector J14 (D-) is in parallel with the D- line of
the J2 USB connector. The BNC connector J15 (D+) is in
parallel with the D+ line of the J2 USB connector. If you want
to use the J14 and J15 BNC connectors you must populate
R1 and R2 with 0Ω resistors. These BNC connectors can be
used to connect test equipment to evaluate the performance
of the IC.
BOARD COMPONENT DEFINITIONS
DESIGNATOR
DESCRIPTION
U1
ISL54209IRUZ IC
J1
“B” type USB Receptacle
J2
“A” type USB Receptacle
J3, J5
Left Stereo Audio Input
J4, J6
Right Stereo Audio Input
J7
Headphone Speaker Jack
J8
COM- BNC Connector
J9
COM+ BNC Connector
J10
VDD Positive Connection
J11
VDD GND Connection
J12
CTRL Logic Control
J13
IN Logic Control
J14
D- BNC Connector
J15
D+ BNC Connector
JP1, JP2
D-/D+ Differential Probe Connection
JP3
IN Pin Connector Selection
Jumper Position 2 to 3 Control through J13
Jumper Position 2 to 1 Control through J1
JP4
Connect 4MΩ Pull-down Resistor to IN Pin
3
July 14, 2008
Application Note 1406
LOGIC
CONTROL
DC POWER
SUPPLY
+3.3V
+
-
COMPUTER
USB PORT
IN
USB DEVICE
USB PORT
GND
VDD
J10
J13
J11
JP3
JP4
USB TO HOST
3 2
J1
JP2
CTRL
J12
USB
TO
DEVICE
J14
1
U1
J2
JP1
J15
J7
HEADPHONE
JACK
J8
AUDIO LEFT
J5
J3
J6
J4
L
AUDIO
SOURCE
J9
COM - COM +
AUDIO RIGHT
R
ISL54209EVAL1Z EVALUATION BOARD
FIGURE 2. BASIC EVALUATION TEST SETUP BLOCK DIAGRAM
Using The Board (Refer to Figure 2)
Lab Equipment
The equipment, external supplies and signal sources
needed to operate the board are listed below:
1. +3V to 5V dc Power Supply
2. Stereo Audio Source (MP3/Radio/CD Player) or Audio
Generator
3. Headphone Set or Audio Analyzer/Oscilloscope
4. Two Standard USB Cables
5. Computer with USB Port
6. USB Device (i.e. USB Memory Stick, MP3 Player with
USB Port, etc.)
Initial Board Setup Procedure
1. Attach the main evaluation board to a DC power supply
at J10 (VDD) and J11 (GND). Positive terminal at J10 and
negative terminal at J11. The supply should be capable of
delivering 3V to 5V and 100mA of current. Set the supply
voltage to 3.3V.
2. Connect the stereo audio source left channel to J3 RCA
connector or J5 BNC connector and right channel to J4
RCA connector or J6 BNC connector.
3. Connect the USB device to the USB “B” type receptacle,
J2 (USB TO DEVICE).
4
Audio Mode Operation
1. Install headphone in the headphone jack, J7. No USB
cable should be connected at the J1 (USB TO HOST)
connector.
2. Logic Control: Put CTRL = Logic “1” and IN = Logic “0”.
You will now be in Audio mode (3Ω audio switches are
ON).
3. Turn the audio source ON. You should hear the music in
the headphones.
4. You can observe the audio signals at the output of the IC
on an oscilloscope or audio analyzer by using the J8 and
J9 BNC connectors. Connect to J8 for Left audio and J9
for right audio.
USB Mode Operation
1. Turn OFF audio stereo source.
2. Remove headphone from J7 Headphone Jack.
3. Logic Control: Put CTRL = Logic “X” and IN = Logic “1”.
You will now be in USB mode (5Ω USB switches are ON).
4. Connect USB cable from computer USB port to the USB
“A” type receptacle, J1 (USB TO HOST) on the evaluation
board. The computer should indicate that it is connected
to the USB device connected at the J2 connector.
5. You will now be able to send and receive data between
the computer and USB device.
6. You can observe the D- and D+ USB digital signals on an
oscilloscope or other test equipment by connecting to the
J8, J14, J9 and J15 BNC connectors or various test
points located on the board. See “Test Points” on page 5.
July 14, 2008
Application Note 1406
7. Remove the 0Ω resistors R1, R2, R3, R4 when evaluating
the performance (i.e. eye diagram, etc.) of the high speed
USB signal. Removal of these resistors disconnects the
headphone jack (J7) and BNC connectors (J8, J9, J14,
J15) from the USB differential lines. These components
when connected will degrade the USB signal. These
components will not be there in an actual application.
If you disconnect the USB cable from J1 and take the IN pin
LOW, the IC will return to Audio mode. You can now plug the
headphone set into headphone jack, turn the audio source
ON to once again play music.
5
Test Points
The board has various test points for connecting probes to
make measurements. The test points available are
described in Table1.
TABLE 1.
DESIGNATOR
DESCRIPTION
TP1
VDD Test Point
TP2
Ground Test Point
TP3
VBUS Test Point
TP4
Audio Left Input Test Point
TP5
Audio Right Input Test Point
JP1
D-/D+ Differential Probe Connection - USB
Device Side of Switch
JP2
D-/D+ Differential Probe Connection - COM Side
of Switch
July 14, 2008
Application Note 1406
J6
J4
AUDIO LEFT
J5
J2
MOUNT
J3
USB
TO
DEVICE
MOUNT
CTRL
J12
A
A
5
1
2
3
4
6
J15
1
D-
D+
A
J14
AUDIO RIGHT
Board Schematic
DNP
100µF
C4
TP5
TP4
0
1
10
2
9
U1
3 DFN10 8
4 GENERIC 7
PACK
5
6
EP
0
A
J11
R6
TP2
R7
TP3
100µF
R1
C3
JP1
1
2
3
4
A
DNP
R2
A
A
COM1
COM2
JP2
1
2
3
4
JP3
0.1µF
10µF
C2
TP1
0
R4
3 USB 2
J1
1
4
J9
COM+
J8
COM-
HEADPHONE
JACK J7
A
USB
TO
HOST
A
R5
4.3M
J13
IN
JP4
TP10
R3
1
4
3
5
2
C1
VDD
VDD
0
J10
C5
GND
OPEN
Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to
verify that the Application Note or Technical Brief is current before proceeding.
For information regarding Intersil Corporation and its products, see www.intersil.com
6
July 14, 2008
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