2
AN1369.0
February 3, 2009
the BNC connectors J13-J14 located on the bottom right side
of the board.
Note: There are 500k
Ω
logic pull-down resistors on the INx
control pins. In external control mode when the digital logic
input lines are left in a floating state, these pull-down resistors
bias the logic inputs to ground.
Switch Terminals
The evaluation board contains components to interface with
all six terminals of the Dual SPDT switch (four terminals for
the SPST switches). The common (COM) terminals of the
switch are located on the right side of the evaluation board.
The Normally Open (NO) and Normally Closed (NC) terminals
of the switch are located on the left side of the evaluation
board. All switch terminals include both RCA jacks and BNC
connectors. The COM terminals also include a headphone
jack (HJ1) for connecting a stereo headphone or line level
plug.
Note: There are 10k
Ω
pull-down resistors on the NCx and
NOx pins of the evaluation board (R21, R22, R23, and R26).
They will need to be depopulated if the user does not desire to
have them.
Refer to Table 1 for a list of the connections on the
ISL540XXEVAL1Z and the associated pin of the IC. The
evaluation board also includes Test Points for convenient
locations to probe specific pins on the IC.
TABLE 1. BOARD COMPONENT TABLE
Note: All switch terminals on the evaluation board have
place holders that can have surface mounted components
placed either in series with the switch path or shunted to
ground. Jumpers on these components allow flexible
configurations. Refer to the Evaluation Board Schematics
located on page 4 for clarification.
Power Supply
The DC power supply connected at banana jacks J1 (V
CC
)
and J2 (GND) provides power to the evaluation board. The
evaluation board requires a +1.8V to +6.5V DC power
supply for proper operation. The power supply should be
capable of delivering 100µ
A
of current.
Logic Control
The state of the ISL540XX IC is determined by the Truth
Table as defined in their respective datasheet. When in
manual operation mode, the logic being toggled by the
SPST switches (S1-S2) will always drive the voltage of the
logic pin to V
CC
for a HIGH and GND for a LOW. In external
control mode, the voltages being driven by an external
source must meet appropriate V
IH
and V
IL
levels as defined
in the datasheet.
The control pins are 1.8V logic compatible up to a +3.3V
supply, which allows for control via a standard µcontroller.
Logic “0” (LOW) when
≤
0.5V (or floating)
Logic “1” (HIGH) when
≥
1.4V
When operating above +3.3V supply, refer to the datasheet
for appropriate logic levels to drive the logic pins. It is always
recommended to drive the logic pins to the positive supply
rail (V
CC
) and GND to minimize power consumption.
Logic States
INPUT SELECT (INX) PINS
If the INx Pins are logic “HIGH”, then the NOx switches are
turned ON and the NCx switches are turned OFF. If the INx
Pins are logic “LOW”, then the NCx switches are turned ON
and the NCx switches are turned OFF.
CLICK AND POP OPERATION (ISL54062, ISL54063,
ISL54064 ONLY)
Single supply audio sources are biased at a DC offset that
generates transients during power ON/OFF of the audio
source. This DC offset is coupled through a blocking
capacitor that is need to remove the DC bias to the speaker,
causing a transient voltage at the load. For example, when
the source is OFF and suddenly turned ON with a DC offset,
the capacitor will develop a voltage equal to the DC offset.
This voltage gets discharged by the speaker causing a click
and pop noise. The ISL54062, ISL54063, and ISL54064 ICs
integrate circuitry to eliminate click and pop noises to the
speaker.
For proper operation of Click and Pop elimination, the switch
terminal that is being connected to the speaker should be
connected through the integrated shunt resistor before
DEVICE
PIN
EVALUATION BOARD
CONNECTION
TEST
POINT
APPLICABLE
IC
V
CC
J1
TP1
All
GND
J2
TP2
All
IN1
S2, J13
TP8
All
IN2
S1, J14
TP9
All
NO1
J11, J12
TP7
ISL54059,
ISL54060,
ISL54062,
ISL54063
NC1
J5, J6
TP4
ISL54059,
ISL54061,
ISL54062,
ISL54064
COM1
J3, J4, HJ1
TP3
All
NO2
J15, J16
TP10
ISL54059,
ISL54060,
ISL54062,
ISL54063
NC2
J7, J8
TP5
ISL54059,
ISL54061,
ISL54062,
ISL54064
COM2
J9, J10, HJ1
TP6
All
Application Note 1369
