ISL54057 Intersil Corporation, ISL54057 Datasheet - Page 7

• Manufacturer Part Number: ISL54057
• Description: Differential 4 to 1 Analog Multiplexer
• Manufacturer: Intersil Corporation

Test Circuits and Waveforms
Detailed Description
The ISL54057 analog switch offer precise switching
capability from a single 1.6V to 3.6V supply with low
on-resistance (0.41Ω) and high speed operation
(t
suited to portable battery powered equipment thanks to the
low operating supply voltage (1.6V), low power consumption
(0.17µW), low leakage currents (60nA max) , and the tiny
µ
flatness provide very low insertion loss and distortion to
applications that require signal reproduction.
Supply Sequencing And Overvoltage Protection
With any CMOS device, proper power supply sequencing is
required to protect the device from excessive input currents
which might permanently damage the IC. All I/O pins contain
ESD protection diodes from the pin to V+ and to GND (see
Figure 7). To prevent forward biasing these diodes, V+ must
be applied before any input signals, and the input signal
voltages must remain between V+ and GND.
If these conditions cannot be guaranteed, then precautions
must be implemented to prohibit the current and voltage at
the logic pin and signal pins from exceeding the maximum
ratings of the switch. The following two methods can be used
to provided additional protection to limit the current in the
event that the voltage at a signal pin or logic pin goes below
ground or above the V+ rail.
TQFN package. The ultra low on-resistance and Ron
ON
SIGNAL
GENERATOR
Crosstalk is measured between adjacent channels with one channel
ON and the other channel OFF.
Signal direction through switch is reversed and worst case values
are recorded.
ANALYZER
= 27ns, t
FIGURE 5. CROSSTALK TEST CIRCUIT
OFF
R
L
Channel
Select
0V or V+
= 18ns). The devices are especially well
COM
A
ADD1
ADD0
V+
x
B
7
C
GND
COM
INH
B
(Continued)
A
x
50Ω
N.C.
ISL54057
Logic inputs can be protected by adding a 1kΩ resistor in
series with the logic input (see Figure 7). The resistor limits
the input current below the threshold that produces
permanent damage, and the sub-microamp input current
produces an insignificant voltage drop during normal
operation.
This method is not acceptable for the signal path inputs.
Adding a series resistor to the switch input defeats the
purpose of using a low R
diodes to the signal pins as shown in Figure 7 will shunt the
fault current to the supply or to ground thereby protecting the
switch. These schottky diodes must be sized to handle the
expected fault current.
IMPEDANCE
ANALYZER
OPTIONAL
PROTECTION
RESISTOR
OPTIONAL
SCHOTTKY
DIODE
OPTIONAL
SCHOTTKY
DIODE
FIGURE 6. CAPACITANCE TEST CIRCUIT
FIGURE 7. OVERVOLTAGE PROTECTION
Ax or Bx
ADD
INH
ON
or
X
switch. Connecting schottky
COMA or COMB
V+
Ax or Bx
GND
V+
C
GND
ADD1
ADD0
INH
September 29, 2006
0V or V+
V
COMX
Channel
Select
FN6379.0