Intersil ISL54211EVAL1Z User Manual

®

ISL54211EVAL1Z

Evaluation Board User’s Manual

Application Note February 13, 2009

Description

The ISL54211EVAL1Z evaluation board is designed to
provide a quick and easy method for evaluating the
ISL54211 USB/Audio Switch IC.

The ISL54211 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 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 ISL54211 TDFN IC is soldered onto the evaluation
board. It is located in the center of the board and is
designated as U1.

The ISL54211 IC has three modes of operation called Audio
mode, USB mode and Mute 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 these 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.
See 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
ISL54211 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

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Picture of Evaluation Board (Top View)

FIGURE 1. ISL54211EVAL1Z EVALUATION BOARD

Board Architecture/Layout

Basic Layout of Evaluation Board

The basic layout of the main board is as follows: Refer to
Figure 1.

• Power and Ground connections are at the top of the board
(J10 and J11).

• Logic control connections are at the top of the board (J12
and J13).

• Audio Source Inputs are at the lower right side of the
board (J3 to 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 32

• USB connection to an upstream host controller
(Computer) is made at connector J1, located on left under­side of the board. USB connection to a downstream USB
device is made at connector J2, located on right under­side of the board.

• Located in the center of the board is the ISL54211 IC (U1).
The evaluation board has a pin 1 dot, to show how the IC
should be oriented on to the evaluation board. The IC pin
1 indicator dot needs to be aligned with the evaluation
board pin 1 dot indicator.

Ω headphone.

1

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

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Copyright Intersil Americas Inc. 2009. All Rights Reserved

Application Note 1408

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 5.0V DC power supply for proper operation. The
power supply should be capable of delivering 100

µA of

current.

Logic Control

The state of the ISL54211 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 V
is in position 2 to 1.

These 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 4M
pull-down resistor from the IN pin to ground by putting a
jumper at JP4. However it is not required for the ISL54211
part because the IN and CTRL pins have internal 4MΩ
pull-down resistors. 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 is LOW, the part will be in the MUTE
mode. In MUTE mode all switches are OPEN.

SETTING UP THE EVALUATION BOARD TO USE THE
COMPUTER V

VOLTAGE TO DRIVE THE “IN’ PIN

BUS

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 V

voltage from the computer through the

BUS

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
V

line of the J1 USB connector to the IN pin of the part.

BUS

Note: With the jumper in this position the J13 banana jack is
no longer connected to the IN pin of the part.

2. A 500k
the V

Ω resistor should be put in series with the IN pin if

voltage is greater than the VDD voltage. This

BUS

series resistor is not on the evaluation board. There is an
internal diode in the IC from the IN pin to VDD that will get

line when the jumper JP3

BUS

Ω

forward biased and draw current as the voltage at the IN pin
exceeds the VDD voltage. With V

3.3V, this resistor will limit the current to around 2.76

= 5.25V and VDD =

BUS

μA and

the voltage at the IN pin will be around 3.6V which is well
above the VinH min level of 1.4V required for proper
operation.

When the computer is not connected at J1, the internal pull­down will pull the IN pin low putting the ISL54211 in the
Audio mode or Mute 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.

When the USB cable is disconnected from the J1 connector
the voltage at the IN pin will be pulled low by the pull-down
resistor and return to the Audio mode or Mute mode
depending on the condition of the CTRL pin.

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 connect to the
RCA jacks J3 and J4, respectfully.

Over a signal range of
have an extremely low r

±1V (0.707V

resistance variation. They can

ON

) these switches

RMS

pass ground referenced audio signals with very low
distortion (<0.05% THD+N) when delivering 15.6mW into a
32W

headphone speaker load. A 3V

signal is acceptable

P-P

but performance will degrade.
The audio channels are AC coupled with 100µF capacitors.

These caps 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
AC coupling capacitors at the output of its drivers then the
capacitors on the evaluation board should be shorted out
(replaced with 0 Ω 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 32
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

W stereo headphone

2

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February 13, 2009

Application Note 1408

the D+ line of the J1 (USB To HOST) connector. These BNC
connectors can be used to connect resistive loads and/or
test equipment to evaluate the performance of the IC.

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
up-stream 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 ISL54211 device will go into
USB mode. The USB switches will be turned ON.

An “A” type USB receptacle labeled USB TO DEVICE (J2) is
located on the right under-side of the board. The USB device
can be plugged directly into this receptacle or through a
standard USB cable.

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
headphone speaker jack, J7. This will prevent the audio load
from interfering with USB signal transmission.

The main purpose of the ISL54211 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, such as
music, into the memory of the media player.

Board Component Definitions

TABLE 1. BOARD COMPONENT DEFINITIONS

DESIGNATOR DESCRIPTION

U1 ISL54211IRUZ 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 Negative 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 - 3 Control through J13
Jumper Position 2 - 1 Control through J1

JP4 Connect 4MΩ Pull-down Resistor to IN Pin

Not required for the ISL54211 part.

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.

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.

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